WO2016028211A1 - Method to detect faults relating to mounting of fuel filters - Google Patents

Method to detect faults relating to mounting of fuel filters Download PDF

Info

Publication number
WO2016028211A1
WO2016028211A1 PCT/SE2015/050883 SE2015050883W WO2016028211A1 WO 2016028211 A1 WO2016028211 A1 WO 2016028211A1 SE 2015050883 W SE2015050883 W SE 2015050883W WO 2016028211 A1 WO2016028211 A1 WO 2016028211A1
Authority
WO
WIPO (PCT)
Prior art keywords
fuel
filter
fuel tank
tank
pump
Prior art date
Application number
PCT/SE2015/050883
Other languages
French (fr)
Inventor
Anders Jonsson
Original Assignee
Scania Cv Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Scania Cv Ab filed Critical Scania Cv Ab
Priority to DE112015003246.0T priority Critical patent/DE112015003246T5/en
Publication of WO2016028211A1 publication Critical patent/WO2016028211A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D27/00—Cartridge filters of the throw-away type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D33/00—Controlling delivery of fuel or combustion-air, not otherwise provided for
    • F02D33/003—Controlling the feeding of liquid fuel from storage containers to carburettors or fuel-injection apparatus ; Failure or leakage prevention; Diagnosis or detection of failure; Arrangement of sensors in the fuel system; Electric wiring; Electrostatic discharge
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
    • F02M37/22—Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines, e.g. arrangements in the feeding system
    • F02M37/32—Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines, e.g. arrangements in the feeding system characterised by filters or filter arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
    • F02M37/22—Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines, e.g. arrangements in the feeding system
    • F02M37/32—Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines, e.g. arrangements in the feeding system characterised by filters or filter arrangements
    • F02M37/42—Installation or removal of filters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
    • B60K15/03—Fuel tanks
    • B60K2015/03118—Multiple tanks, i.e. two or more separate tanks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
    • B60K15/03—Fuel tanks
    • B60K2015/03118—Multiple tanks, i.e. two or more separate tanks
    • B60K2015/03138—Pumping means between the compartments
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
    • B60K15/03—Fuel tanks
    • B60K2015/03236—Fuel tanks characterised by special filters, the mounting thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2200/00—Type of vehicle
    • B60Y2200/10—Road Vehicles
    • B60Y2200/14—Trucks; Load vehicles, Busses
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D2041/224—Diagnosis of the fuel system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/3005—Details not otherwise provided for

Definitions

  • the present invention relates to a method for detection of errors with respect to fitting of a fuel filter in a fuel system for a combustion engine according to claim 1.
  • the invention also relates to a fuel system according to claim 10, a combustion engine with such a fuel system according to claim 13 and a vehicle with such a fuel system accord- ing to claim 14.
  • a combustion engine such as a piston engine, which is driven by diesel or petrol, is equipped with a fuel system to transport fuel from one or several fuel tanks to the combustion engine's injection system.
  • the fuel system may comprise a low pressure circuit and a high pressure circuit, where the low pressure circuit comprises one or several fuel pumps/supply pumps, which may be operated mechanically by the combustion engine or be operated by an electric motor.
  • the fuel pumps create a fuel flow and a pressure to transport the fuel to the high pressure circuit and an accumulator, which may in the form of a so-called common rail, and further to the combustion en- gine's injection system, which supplies the fuel to the combustion engine's combustion chamber.
  • Common rail may be excluded and the fuel system may instead comprise another form of an injection system, for example a piezo- or a unit injection system.
  • Fuel systems also comprise fuel filters for filtration of the fuel before it reaches the combustion engine's injection system.
  • the combustion engine and its injection system are sensitive to impurities and may be negatively impacted if the fuel is too polluted. Impurities may mean solid particles, gas or liquid. Even if the fuel only comprises only a small amount of contaminations, the consequence may be that the combustion engine may not be driven with the fuel or that the injection system is damaged.
  • Fuel systems therefore comprise a fuel filter, which both filters away particles and separates water occurring in the fuel.
  • a fuel filter may, for various reasons, need to be replaced, and when the new fuel filter is fitted, it is important that the fuel filter is fitted correctly and that the fitted fuel filter is intended for the purpose.
  • Each vehicle has a specified type of fuel filter that should be used, and if another type of fuel filter is fitted, there may be consequences, such as operational disruptions and failures.
  • operational disruptions and failures For example, if a fuel filter with a poorer filtering property is fitted, the risk of contaminations reaching and damaging the combustion engine's injection system increases. Similarly, an incorrectly fitted fuel filter may entail that contaminations pass through it and thus reach and damage the combustion engine's injection system, which may cause operational disruptions and failures. How- ever, it is difficult to discover if a fuel filter has been fitted incorrectly, or if the wrong type of fuel filter has been fitted. Often, such errors are not discovered until it is too late, and the operational disruption is already a fact.
  • Document US7615151 shows a system for detection of whether a fuel filter is incor- rectly fitted or missing in a fuel system, wherein the fuel filter comprises a device that determines whether the fuel filter has been fitted in a correct position or in an incorrect position.
  • a magnetically controlled valve is controlled in such a way that the flow through the fuel filter is at least partly blocked.
  • Document EP1143232 shows a device to measure the pressure difference over a fuel filter arranged in connection with the combustion engine.
  • an evaluation device carries out a remedying measure, for example, a signal may be emitted.
  • a pressure difference which falls below the reference pressure may entail that the fuel filter is incorrectly fitted or missing.
  • Pressure sensors are arranged before and after the fuel filter to determine the pressure difference. Such a device requires extra components and is sensitive to disruptions. If any of the pressure sensors should break, errors with respect to the fitting of the fuel filter may no longer be identified.
  • prior art solutions in this field there is thus a need to further develop a method to detect errors relating to the fitting of a fuel filter in a fuel system, which is reliable and cost effective.
  • the objective of the present invention is to achieve a method, which is reliable and cost effective, to detect errors relating to the fitting of a fuel filter in a fuel system.
  • the objective of the present invention is to achieve a method, which minimises the risk of operational disruptions, to detect errors relating to the fitting of a fuel filter in a fuel system.
  • Another objective of the invention is to achieve a fuel system for a combustion engine, wherein detection of errors with respect to the fitting of fuel filters may occur in a reliable and cost effective manner.
  • a method for detection of errors relating to the fitting of a fuel filter in a fuel system for a combustion engine comprises a first fuel tank, a second fuel tank, a first fuel conduit arranged in connection with the first fuel tank and the second fuel tank, a first fuel pump arranged to supply fuel from the second fuel tank to the first fuel tank via the first fuel conduit, a second fuel pump arranged to supply fuel from the first fuel tank to a high pressure circuit in the fuel system, and a first fuel filter arranged downstream of the first fuel pump and upstream of the second fuel pump.
  • the method suitably comprises the steps of defining a tolerance interval for pressure drops over the first fuel filter; of controlling the first fuel pump to supply fuel from the second fuel tank to the first fuel tank via the first fuel filter; of calculating a pressure drop over the first fuel filter and of determining whether an error has arisen when the first fuel filter was fitted, by way of controlling whether the calculated pressure drop for the first fuel filter is within the defined tolerance interval.
  • the defined tolerance interval for the pressure drop over the first fuel filter is preferably based on a reference fuel filter intended for the purpose.
  • the reference fuel filter is a fuel filter that is intended for use in a fuel system and thus meets the desired requirements regarding filtering properties and quality.
  • the defined tolerance interval for the pressure drop over the first fuel filter is the interval, within which the pressure drop ought to be, if a fuel filter intended for this purpose has been correctly fitted. That is to say, the defined tolerance interval for the pressure drop over the first fuel filter is the interval, within which the pressure drop ought to be, if the first fuel filter intended for this purpose is a fuel filter corresponding to the reference fuel filter and has been correctly fitted.
  • the defined tolerance interval may also be based on the fuel type intended for the purpose.
  • the type of fuel used in a fuel system impacts the pressure drop over a certain fuel filter.
  • a certain fuel filter for example, a higher pres- sure drop is obtained when a fuel with a higher viscosity is used, than when a fuel with a lower viscosity is used.
  • bio-diesel has a higher viscosity than diesel and thus the pressure drop over the reference fuel filter would, when bio-diesel is used, differ from the pressure drop when diesel is used.
  • the tolerance interval may be defined with consideration to the type of fuel that is used in the fuel system.
  • the toler- ance interval may be defined by manual feeding into a control device arranged in the fuel system. Alternatively, the tolerance interval is defined automatically in the control device.
  • Errors are suitably considered to have arisen when the first fuel filter was fitted, in the event that the calculated pressure drop for the first fuel filter is outside of the tolerance interval.
  • the tolerance interval is suitably defined as an interval between a maximum value and a minimum value, and if the calculated pressure drop is outside the tolerance interval, this therefore means that the calculated pressure drop either exceeds the maximum value or falls below the minimum value.
  • a detected error indicates that the first fuel filter is incorrectly fitted or that the wrong fuel filter has been fitted.
  • a wrong fuel filter means a fuel filter which does not match the reference fuel filter.
  • a calculated pressure drop below the minimum value of the tolerance interval may indicate that the wrong type of fuel filter is fitted, or that the fuel filter is incorrectly fitted.
  • a calculated pressure drop exceeding the maximum value of the tolerance interval may indicate that the fuel filter is incorrectly fitted, or that a fuel with a higher viscosity than the viscosity of the fuel intended for the reference fuel filter is used.
  • a comparison of the calculated pressure drop with the defined tolerance interval may also detect that the fuel filter is completely missing. A calculated pressure drop falling below the minimum value of the tolerance interval may thus indicate that no fuel filter has been fitted between the first and the second fuel pumps.
  • the first fuel filter may comprise a filter house and a filter element fitted in the filter house.
  • the filter element may thus have been incorrectly fitted, a wrong filter element may have been fitted or no filter element may have been fitted in the filter house.
  • the method according to the present invention is carried out in connection with a fuel filter replacement or a fitting of the first fuel filter.
  • a fuel filter replacement or a fitting of the first fuel filter By actively controlling the first fuel pump to feed fuel through the first fuel filter directly when fitting the first fuel filter, calculating the pressure drop over the first fuel filter and verifying whether it is within a defined tolerance interval, within which the pressure drop ought to be, an efficient manner of detecting errors at an early stage is achieved. This ensures detection of an incorrectly fitted fuel filter or a fitted wrong fuel filter at an early stage, and accordingly the error may be fixed quickly.
  • the fuel filter also has a minimal degree of clogging, so that a reliable calculation of the pressure drop may be achieved.
  • the first fuel filter thus constitutes a so-called pre-filter.
  • the first fuel pump is suitably operated by a first electric motor
  • the second fuel pump is suitably operated by a second electric motor.
  • an electrically operated fuel pump a broader control interval is allowed than with a mechanic pump, which is usually operated and controlled by a combustion engine, and in particular by the engine speed of the combustion engine.
  • An electrically operated fuel pump may be controlled towards other parameters than engine speed, e.g. fuel filter clogging degree and pressure inside the fuel conduits.
  • the pressure drop over the first fuel filter is calculated based on a flow through the first fuel filter.
  • the flow through the first fuel filter is preferably determined by way of measuring changes in the level of fuel in the first fuel tank during a predetermined period of time, which level change is determined with a level sensor arranged in the first fuel tank. By reading the level sen- sor' s signals and thus determining how the fuel volume in the first fuel tank has changed during a certain time, the flow through the first fuel filter may be determined. Alternatively, the flow may be determined by way of measuring how long it takes to fill the first fuel tank with the first fuel pump. According to one aspect of the present invention, the pressure drop over the first fuel filter is calculated based on the rotational speed and/or power consumption of the first fuel pump.
  • the rotational speed of the first fuel pump may be determined by way of measuring the voltage or power consumption of the first electric motor (and thus the first fuel pump). By measuring the first fuel pump's rotational speed and/or power consumption, the flow generated by the first fuel pump may be determined. At the same time, a verification that the first fuel pump functions as desired is obtained. By comparing the actual determined flow through the first fuel filter with the flow generated by the first fuel pump, the pressure drop over the first fuel filter may be calculated.
  • the pressure drop over the first fuel filter is calculated based on the temperature of the fuel in the first fuel tank.
  • the viscosity of the fuel may be determined.
  • the viscosity of the fuel may impact the pressure drop over the first fuel filter, and by having regard to the viscosity the pressure drop may be calculated accurately and reliably.
  • the step of verifying that the calculated pressure drop for the first fuel filter is within the defined tolerance interval com- prises generating an error message when an error has been detected.
  • the error message may suitably be presented in the vehicle to the driver, or in a diagnostic tool at a garage or a service place. Accordingly, the detected error may be made visible and addressed.
  • the error message may be saved in a control device arranged in the vehicle.
  • the step of verifying that the calculated pressure drop or the first fuel filter is within the tolerance interval comprises limiting the fuel supply to the combustion engine when an error has been detected.
  • the fuel supply to the combustion engine may be limited by way controlling the first fuel pump in such a way that the fuel flow to the first fuel tank is limited.
  • the second fuel pump is controlled in such a way that the fuel supply to the high pressure circuit is limited.
  • the fuel supply to the combustion engine By limiting the fuel supply to the combustion engine, the progress of the vehicle is limited as long as the error remains. When the error has been corrected, the limitation of the fuel supply suitably ceases. This prevents that the detected error relating to the fitting of the fuel filter is missed or ignored. This ensures, for example, that a fuel filter with poorer filtering properties than a reference fuel filter intended for the purpose is not used.
  • a method is achieved to detect errors relating to fitting of a fuel filter in a fuel system, which method minimises the risk of operational disruptions.
  • the start of the combustion engine is prevented when the calculated pressure drop is outside the tolerance interval, and errors relating to fitting thus have been detected.
  • a fuel system for a combustion engine, comprising a first fuel tank, a second fuel tank, a first fuel conduit arranged in connection with the first fuel tank and the second fuel tank, a first fuel pump, arranged to feed fuel from the second fuel tank to the first fuel tank through the first fuel conduit, a second fuel pump arranged to feed fuel from the first fuel tank to a high pressure circuit, and a first fuel filter arranged downstream of the first fuel pump and upstream of the second fuel pump.
  • the fuel system also comprises a control device, arranged to provide a defined tolerance interval for a pressure drop over a reference fuel filter intended for this purpose, of controlling the first fuel pump to supply fuel from the second fuel tank to the first fuel tank via the first fuel filter, of calculating a pressure drop over the first fuel filter and determining whether an error has arisen when the first fuel filter was fitted, by way of controlling whether the calculated pressure drop is within the defined tolerance interval.
  • a control device arranged to provide a defined tolerance interval for a pressure drop over a reference fuel filter intended for this purpose, of controlling the first fuel pump to supply fuel from the second fuel tank to the first fuel tank via the first fuel filter, of calculating a pressure drop over the first fuel filter and determining whether an error has arisen when the first fuel filter was fitted, by way of controlling whether the calculated pressure drop is within the defined tolerance interval.
  • the defined tolerance interval may be fed manually into the control device, or alterna- tively it may be defined automatically in the control device.
  • the tolerance interval may for example be stored in the control device when the vehicle is manufactured, and updated when the vehicle's software is updated, for example at service.
  • the control device is preferably arranged to calculate the pressure drop over the first fuel filter based on a flow through the first fuel filter.
  • a level sensor is preferably arranged in the first fuel tank.
  • the control device is suitably arranged in connection with the level sensor and the first fuel pump.
  • the control device is arranged in connection with the first electric motor, which operates the first fuel pump.
  • the control device is arranged in connection with the second electric motor, which operates the second fuel pump. In this manner, the control device may obtain information about the respective fuel pump.
  • the control device may consist of a logic in a combustion engine control device, or alternatively the control device may consist of a separate control device, which is connected with the combustion engine control device.
  • the control device is suitably arranged to calculate the pressure drop over the first fuel filter based on the first fuel pump's rotational speed and/or power consumption.
  • the control device is also suitably arranged to calculate the pressure drop over the first fuel filter based on the temperature of the fuel in the first fuel tank.
  • the control device thus obtains signals from the level sensor, from the first and the second fuel pump and from a temperature sensor in the first fuel tank.
  • the control device may also obtain signals from one or several other control devices in the vehicle, for example the combustion engine control device.
  • the first fuel tank is adapted so that it holds a smaller volume than the second fuel tank. This design entails a less bulky first fuel tank, which is easier to arrange inside a chassis. Thus, a non-bulky fuel system is achieved.
  • the first fuel tank holds 20-50 litres and the second fuel tank holds 300-1,000 litres.
  • a third fuel tank may be arranged in connection with the second fuel tank.
  • the second fuel pump is arranged in the first fuel tank.
  • the second fuel pump is protected from the environment and a natural cooling of the fuel in the first fuel tank is obtained.
  • the first fuel pump and the first fuel filter are also arranged inside the first fuel tank.
  • a computer program is provided to detect errors in relation to the fitting of a fuel filter, wherein said computer program comprises program code to cause the control device or another computer connected to the control device to carry out the method steps according to the present invention.
  • a computer program product comprising program code stored on a me- dium readable by a computer, is provided in order to perform the method steps according to the present invention, when said program code is executed in the control device or in another computer connected to the control device.
  • Said program code may be stored in a non- volatile manner on said computer-readable medium.
  • Fig. 1 shows a schematic side view of a vehicle, which comprises a fuel system according to the present invention
  • Fig. 2 shows a coupling diagram for a fuel system according to the present invention
  • Fig. 3 shows a flow chart of a method to detect errors relating to the fitting of a fuel filter in a fuel system according to the present invention.
  • VENTION Fig. 1 shows a schematic side view of a vehicle 1, which vehicle comprises a fuel system 4 for a combustion engine 2 according to the present invention.
  • the combustion engine 2 is connected to a gearbox 6, which is further connected to the driving wheels 8 of the vehicle 1 via a transmission.
  • the vehicle also comprises a chassis 10.
  • Fig. 2 shows a coupling diagram for a fuel system 4 in a combustion engine 2 according to the present invention.
  • the fuel system 4 comprises a high pressure pump 12, an accumulator in the form of a so-called common rail 14, and an injection system sche- matically displayed in the form of a fuel injector 16, which are arranged in the combustion engine 2 (the combustion engine 2 is displayed in Fig. 1) and which constitute the fuel system's 4 high pressure circuit 18.
  • the common rail may be replaced by another form of an injection system, e.g. a piezo or a unit injection system.
  • the fuel system 4 also comprises a first fuel tank 20, a second fuel tank 22, a first fuel pump 24, arranged to feed fuel from the second fuel tank 22 to the first fuel tank 20 through a first fuel conduit 26, a second fuel pump 28 arranged to feed fuel from the first fuel tank 20 to the high pressure circuit 18, and a first fuel filter 30 arranged downstream of the first fuel pump 24 and upstream of the second fuel pump 28.
  • These components may be arranged at the vehicle's chassis 10 (the chassis 10 is displayed in Fig. 1).
  • a second fuel filter 32 is arranged downstream of the second fuel pump 28 and upstream of the high pressure pump 12 in the fuel system 4.
  • the first fuel filter 30 suitably consists of a pre-filter
  • the second fuel filter 32 suitably consists of a main fuel filter.
  • the fuel system 4 comprises a fuel return conduit 34, through which fuel is returned from the fuel system's 4 high pressure circuit 18 back to the first fuel tank 20.
  • the two fuel tanks 20, 22 are in their respective top parts connected with a ventilation conduit 36, which communicates with the surrounding environment.
  • the ventilation conduit 36 ensures that the pressure in the respective tanks 20, 22 is, and remains, sub- stantially the same and equal to the ambient air pressure, regardless of how much fuel is in the respective tanks.
  • the first fuel tank 20 is adapted so that it holds a smaller volume than the second fuel tank 22, which second fuel tank 22 represents a main fuel tank.
  • the first fuel pump 24 is, according to Fig. 2, arranged between the first fuel tank 20 and the second fuel tank 22.
  • the first fuel pump 24 is operated by a first electric motor Ml.
  • the second fuel pump 28 is operated by a second electrical engine M2 and is arranged inside the first fuel tank 20, and is thus protected from the environment and cooled by the fuel. Between the first fuel tank 20 and the second fuel tank 22 an overflow conduit 38 is arranged, so that fuel may be transported across from the first fuel tank 20 to the second fuel tank 22, if the first fuel tank 20 becomes overfilled.
  • the second fuel pump's 28 main task is to feed the fuel from the first fuel tank 20, via a second fuel conduit 40, through the main fuel filter 32 and further to the high pressure circuit 18. The fuel is then fed, at a high pressure, to the common rail 14 and further along to the injection system 16 of the combustion engine 2.
  • the first fuel filter 30 is preferably a fine mesh, water separating filter.
  • a coarse mesh sieve 42 is arranged, through which the first fuel pump 24 sucks fuel.
  • the coarse mesh sieve 42 filters away particles above a certain predetermined size.
  • the first fuel pump 24 then pressurises the fuel and feeds it through the first fuel filter 30, via the first fuel conduit 26, further along to the first fuel tank 20.
  • the fuel in the first fuel tank 20 has thus passed both a coarse mesh sieve 42 and fine mesh pre-filter 30, which entails that the second fuel pump 28, which is arranged in the first fuel tank 20, is protected against impurities.
  • a control device 44 is arranged in connection with the first fuel pump and the second fuel pump.
  • the control device 44 may be a computer with software suitable for this purpose.
  • Another computer 46 may be connected to the control device 44.
  • the control device 44 is arranged to provide a defined tolerance interval for pressure drops over the first fuel filter 30. Tolerance intervals are suitably based on a reference fuel filter intended for the purpose. That is to say, the defined tolerance interval is a tolerance interval for pressure drops, which should be obtained if a correct first fuel filter has been fitted correctly in the fuel system 4.
  • the defined tolerance interval may be fed manually into the control device 44, or may be automatically defined in the control device 44.
  • control device 44 is arranged to control the first fuel pump 24 to feed fuel from the second fuel tank 22 to the first fuel tank 20, and to calculate a pressure drop over the first fuel filter 30.
  • the control device 44 is also arranged to control that the calculated pressure drop over the first fuel filter 30 is within the defined tolerance interval, and thus to determine whether an error has arisen when the first fuel filter 30 was fitted.
  • the control device 44 is also arranged to generate an error message if an error has been detected.
  • the power consumption or the power output/voltage of the fuel pump's 24 electric motor Ml may be determined.
  • the control device 44 may determine the rotational speed of the first fuel pump 24. The rotational speed may be used by the control device 44 to calculate the pressure drop over the first fuel filter 30.
  • a level sensor 48 is arranged in the first fuel tank 20, in order to identify the fuel level in the first fuel tank 20.
  • the level sensor 48 is arranged in connection with the control device 44.
  • the control device 44 may thus obtain information about level changes in the fuel volume of the first fuel tank 20 during a predetermined time period. With level changes the control device 44 may determine the flow through the first fuel filter 30, and based on the flow the control device 44 may calculate the pressure drop over the first fuel filter 30.
  • the level sensor 48 may be used to determine when the fuel level in the first fuel tank 20 falls below a certain level, so that the first fuel pump 24 is controlled to feed fuel from the second fuel tank 22 to the first fuel tank 20.
  • Fig. 3 shows a flow chart of a method to detect errors relating to the fitting of a fuel filter in a fuel system 4 for a combustion engine 2 according to the present invention.
  • the fuel system 4 is suitably adapted as described in Fig. 2, and thus comprises a first fuel tank 20, a second fuel tank 22, a first fuel conduit 26 arranged in connection with the first fuel tank 20 and the second fuel tank 22, a first fuel pump 24, arranged to feed fuel from the second fuel tank 22 to the first fuel tank 20 through the first fuel conduit 26, a second fuel pump 28, arranged to feed fuel from the first fuel tank 20 to a high pressure circuit 18 in the fuel system 4, and a first fuel filter 30 arranged downstream of the first fuel pump 24 and upstream of the second fuel pump 28.
  • the method comprises the steps to:
  • the defined tolerance interval is preferably based on a reference fuel filter intended for the purpose. In this manner, a tolerance interval, within which the pressure drop ought to be placed is obtained, when a fuel filter for the intended purpose has been fitted correctly.
  • the defined tolerance interval may also be based on the fuel type in the fuel system 4. Thus, the tolerance interval is suitably defined with consideration for the type of fuel filter that is intended for the purpose and/or the type of fuel that is intended for the purpose.
  • the pressure drop over the first fuel filter 30 is calculated in step c) based on a flow through the first fuel filter 30.
  • the flow through the first fuel filter 30 is preferably determined by way of measuring changes in the level of fuel in the first fuel tank 20 during a predetermined period of time, which level change is determined with a level sensor 48, arranged in the first fuel tank 20. By reading the level sensor's 48 signals and thus determining how the fuel volume in the first fuel tank 20 has changed during a certain time, the flow through the first fuel filter 30 may be determined. Al- ternatively, the flow may be determined by way of measuring how long it takes to fill the first fuel tank 20 with the first fuel pump 24.
  • the pressure drop over the first fuel filter 30 is also calculated based on the first fuel pump's 24 rotational speed and/or power consumption.
  • the rotational speed of the first fuel pump 24 may be determined by way of measuring the voltage or power consumption of the first electric motor Ml (and thus the first fuel pump 24). By meas- uring the first fuel pump's 24 rotational speed and/or power consumption, the flow generated by the first fuel pump 24 may be determined. By comparing the actual determined flow through the first fuel filter 30 with the flow generated by the first fuel pump 24, the pressure drop over the first fuel filter 30 may be calculated.
  • the pressure drop over the first fuel filter 30 is also calculated based on the temperature of the fuel in the first fuel tank 20.
  • the viscosity of the fuel may be determined.
  • the viscosity of the fuel may impact the pressure drop over the first fuel filter 30, and by having regard to the viscosity the pressure drop may be calculated accurately and reliably.
  • the step d) comprises generating an error message when an error has been detected.
  • the error message may suitably be presented in the vehicle 1 to the driver, or in a diagnostic tool at a garage or a service place. Accordingly, the detected error may be made visible and addressed.
  • the error message may be saved in a control device 44, arranged in the vehicle 1.
  • the step d) comprises limiting the fuel supply to the combustion engine 2 when an error has been detected.
  • the fuel supply to the combustion engine 2 is limited by way of controlling the first fuel pump 24 in such a way that the fuel flow to the first fuel tank 20 is limited.
  • the second fuel pump 28 is controlled in such a way that the fuel supply to the high pressure circuit 18 is limited.
  • step d) comprises the step of preventing start of the combustion engine 2 when the calculated pressure drop is outside the tolerance interval, and errors relating to fitting of a fuel filter have thus been detected.
  • steps a) - d) are carried out in connection with replacement of the first fuel filter 30 or fitting of the first fuel filter 30.
  • errors relating to the fitting of the fuel filter 30 may be detected at an early stage and the error may be addressed before serious consequences, such as operational disruptions, arise.
  • a computer program P is provided, stored in the control device 44 and/or the computer 46, which program may comprise procedures to detect errors relating to the fitting of a fuel filter according to the method described herein.
  • the program P may be stored in an executable manner, or in a compressed manner, in a memory M and/or a read/write memory R.
  • the invention also relates to a computer program product, comprising program code stored in a medium readable by a computer, to perform the method steps specified above, when said program code is executed in the control device 44, or another computer 46 connected to the control device 44.
  • Said program code may be stored in a non- volatile way on said medium readable by a computer 46.

Abstract

The invention relates to a method for detection of errors relating to the fitting of a fuel filter in a fuel system (4) for a combustion engine (2), which fuel system (4) comprises a first fuel tank (20), a second fuel tank (22), a first fuel conduit (26) arranged in connection with the first fuel tank (20) and the second fuel tank (22), a first fuel pump (24), arranged to feed fuel from the second fuel tank (22) to the first fuel tank (20) through the first fuel conduit (26), a second fuel pump (28), arranged to feed fuel from the first fuel tank (20) to a high pressure circuit (18) in the fuel system (4), and a first fuel filter (30) arranged downstream of the first fuel pump (24) and upstream of the second fuel pump (28). The method comprises the steps to: a) define a tolerance interval for pressure drops over the first fuel filter (30); b) control the first fuel pump (24) to feed fuel from the second fuel tank (22) to the first fuel tank (20) through the first fuel filter (30); c) calculate a pressure drop over the first fuel filter (30); and d) determine if an error has arisen when the first fuel filter (30) was fitted, by verifying whether the calculated pressure drop is within the defined tolerance interval. The invention also relates to a fuel system (4), a combustion engine (2) comprising said fuel system (4) and a vehicle (1) comprising said fuel system (4).

Description

Method to detect faults relating to mounting of fuel filters
BACKGROUND OF THE INVENTION AND PRIOR ART
The present invention relates to a method for detection of errors with respect to fitting of a fuel filter in a fuel system for a combustion engine according to claim 1. The invention also relates to a fuel system according to claim 10, a combustion engine with such a fuel system according to claim 13 and a vehicle with such a fuel system accord- ing to claim 14.
A combustion engine, such as a piston engine, which is driven by diesel or petrol, is equipped with a fuel system to transport fuel from one or several fuel tanks to the combustion engine's injection system. The fuel system may comprise a low pressure circuit and a high pressure circuit, where the low pressure circuit comprises one or several fuel pumps/supply pumps, which may be operated mechanically by the combustion engine or be operated by an electric motor. The fuel pumps create a fuel flow and a pressure to transport the fuel to the high pressure circuit and an accumulator, which may in the form of a so-called common rail, and further to the combustion en- gine's injection system, which supplies the fuel to the combustion engine's combustion chamber. Common rail may be excluded and the fuel system may instead comprise another form of an injection system, for example a piezo- or a unit injection system.
Fuel systems also comprise fuel filters for filtration of the fuel before it reaches the combustion engine's injection system. The combustion engine and its injection system are sensitive to impurities and may be negatively impacted if the fuel is too polluted. Impurities may mean solid particles, gas or liquid. Even if the fuel only comprises only a small amount of contaminations, the consequence may be that the combustion engine may not be driven with the fuel or that the injection system is damaged. Fuel systems therefore comprise a fuel filter, which both filters away particles and separates water occurring in the fuel. A fuel filter may, for various reasons, need to be replaced, and when the new fuel filter is fitted, it is important that the fuel filter is fitted correctly and that the fitted fuel filter is intended for the purpose. Each vehicle has a specified type of fuel filter that should be used, and if another type of fuel filter is fitted, there may be consequences, such as operational disruptions and failures. For example, if a fuel filter with a poorer filtering property is fitted, the risk of contaminations reaching and damaging the combustion engine's injection system increases. Similarly, an incorrectly fitted fuel filter may entail that contaminations pass through it and thus reach and damage the combustion engine's injection system, which may cause operational disruptions and failures. How- ever, it is difficult to discover if a fuel filter has been fitted incorrectly, or if the wrong type of fuel filter has been fitted. Often, such errors are not discovered until it is too late, and the operational disruption is already a fact.
Document US7615151 shows a system for detection of whether a fuel filter is incor- rectly fitted or missing in a fuel system, wherein the fuel filter comprises a device that determines whether the fuel filter has been fitted in a correct position or in an incorrect position. In cases where the fuel filter is incorrectly fitted, a magnetically controlled valve is controlled in such a way that the flow through the fuel filter is at least partly blocked. Such a solution requires specially adapted fuel filters with a complex con- struction, which also makes the fuel system inflexible since only a specific type of filter element may be used in the filter house of the fuel filter.
Document EP1143232 shows a device to measure the pressure difference over a fuel filter arranged in connection with the combustion engine. When the pressure difference is below a reference value, an evaluation device carries out a remedying measure, for example, a signal may be emitted. A pressure difference which falls below the reference pressure may entail that the fuel filter is incorrectly fitted or missing. Pressure sensors are arranged before and after the fuel filter to determine the pressure difference. Such a device requires extra components and is sensitive to disruptions. If any of the pressure sensors should break, errors with respect to the fitting of the fuel filter may no longer be identified. Despite prior art solutions in this field, there is thus a need to further develop a method to detect errors relating to the fitting of a fuel filter in a fuel system, which is reliable and cost effective. SUMMARY OF THE INVENTION
The objective of the present invention is to achieve a method, which is reliable and cost effective, to detect errors relating to the fitting of a fuel filter in a fuel system. The objective of the present invention is to achieve a method, which minimises the risk of operational disruptions, to detect errors relating to the fitting of a fuel filter in a fuel system.
Another objective of the invention is to achieve a fuel system for a combustion engine, wherein detection of errors with respect to the fitting of fuel filters may occur in a reliable and cost effective manner.
These objectives are achieved with a method to detect errors relating to the fitting of fuel filters in a fuel system of the type specified at the beginning, which method is characterised by the features specified in the characterising portion of claim 1.
These objectives are also achieved with a fuel system according to the characterising portion of claim 10, a combustion engine with such a fuel system according to the characterising portion of claim 13, a vehicle with such a fuel system according to the characterising portion of claim 14, a computer program according to claim 15 and a computer program product according to claim 16.
According to one aspect of the present invention, a method for detection of errors relating to the fitting of a fuel filter in a fuel system for a combustion engine is provided, which fuel system comprises a first fuel tank, a second fuel tank, a first fuel conduit arranged in connection with the first fuel tank and the second fuel tank, a first fuel pump arranged to supply fuel from the second fuel tank to the first fuel tank via the first fuel conduit, a second fuel pump arranged to supply fuel from the first fuel tank to a high pressure circuit in the fuel system, and a first fuel filter arranged downstream of the first fuel pump and upstream of the second fuel pump. The method suitably comprises the steps of defining a tolerance interval for pressure drops over the first fuel filter; of controlling the first fuel pump to supply fuel from the second fuel tank to the first fuel tank via the first fuel filter; of calculating a pressure drop over the first fuel filter and of determining whether an error has arisen when the first fuel filter was fitted, by way of controlling whether the calculated pressure drop for the first fuel filter is within the defined tolerance interval. In this manner, a method for detection of errors relating to the fitting of a fuel filter in a fuel system is achieved, which method is flexible, reliable and cost effective.
The defined tolerance interval for the pressure drop over the first fuel filter is preferably based on a reference fuel filter intended for the purpose. The reference fuel filter is a fuel filter that is intended for use in a fuel system and thus meets the desired requirements regarding filtering properties and quality. Thus, the defined tolerance interval for the pressure drop over the first fuel filter is the interval, within which the pressure drop ought to be, if a fuel filter intended for this purpose has been correctly fitted. That is to say, the defined tolerance interval for the pressure drop over the first fuel filter is the interval, within which the pressure drop ought to be, if the first fuel filter intended for this purpose is a fuel filter corresponding to the reference fuel filter and has been correctly fitted. The defined tolerance interval may also be based on the fuel type intended for the purpose. The type of fuel used in a fuel system impacts the pressure drop over a certain fuel filter. For a certain fuel filter, for example, a higher pres- sure drop is obtained when a fuel with a higher viscosity is used, than when a fuel with a lower viscosity is used. For example, bio-diesel has a higher viscosity than diesel and thus the pressure drop over the reference fuel filter would, when bio-diesel is used, differ from the pressure drop when diesel is used. Thus, the tolerance interval may be defined with consideration to the type of fuel that is used in the fuel system. The toler- ance interval may be defined by manual feeding into a control device arranged in the fuel system. Alternatively, the tolerance interval is defined automatically in the control device. Errors are suitably considered to have arisen when the first fuel filter was fitted, in the event that the calculated pressure drop for the first fuel filter is outside of the tolerance interval. The tolerance interval is suitably defined as an interval between a maximum value and a minimum value, and if the calculated pressure drop is outside the tolerance interval, this therefore means that the calculated pressure drop either exceeds the maximum value or falls below the minimum value.
Preferably, a detected error indicates that the first fuel filter is incorrectly fitted or that the wrong fuel filter has been fitted. A wrong fuel filter means a fuel filter which does not match the reference fuel filter. A calculated pressure drop below the minimum value of the tolerance interval may indicate that the wrong type of fuel filter is fitted, or that the fuel filter is incorrectly fitted. A calculated pressure drop exceeding the maximum value of the tolerance interval may indicate that the fuel filter is incorrectly fitted, or that a fuel with a higher viscosity than the viscosity of the fuel intended for the reference fuel filter is used.
A comparison of the calculated pressure drop with the defined tolerance interval may also detect that the fuel filter is completely missing. A calculated pressure drop falling below the minimum value of the tolerance interval may thus indicate that no fuel filter has been fitted between the first and the second fuel pumps.
The first fuel filter may comprise a filter house and a filter element fitted in the filter house. In the event that the calculated pressure drop is outside the defined tolerance interval, the filter element may thus have been incorrectly fitted, a wrong filter element may have been fitted or no filter element may have been fitted in the filter house.
Preferably, the method according to the present invention is carried out in connection with a fuel filter replacement or a fitting of the first fuel filter. By actively controlling the first fuel pump to feed fuel through the first fuel filter directly when fitting the first fuel filter, calculating the pressure drop over the first fuel filter and verifying whether it is within a defined tolerance interval, within which the pressure drop ought to be, an efficient manner of detecting errors at an early stage is achieved. This ensures detection of an incorrectly fitted fuel filter or a fitted wrong fuel filter at an early stage, and accordingly the error may be fixed quickly. At fitting the fuel filter also has a minimal degree of clogging, so that a reliable calculation of the pressure drop may be achieved. This minimises the risk of an incorrectly fitted fuel filter or a fitted wrong fuel filter causing contaminations to move into the injection system of the combustion engine and causing operational disruptions. Detecting errors relating to the fitting of the first fuel filter in the fuel system also minimises the risk of damage to the second fuel pump, downstream of the fuel filter, due to contaminations. The first fuel filter thus constitutes a so-called pre-filter.
The first fuel pump is suitably operated by a first electric motor, and the second fuel pump is suitably operated by a second electric motor. With an electrically operated fuel pump a broader control interval is allowed than with a mechanic pump, which is usually operated and controlled by a combustion engine, and in particular by the engine speed of the combustion engine. An electrically operated fuel pump may be controlled towards other parameters than engine speed, e.g. fuel filter clogging degree and pressure inside the fuel conduits. According to one aspect of the present invention, the pressure drop over the first fuel filter is calculated based on a flow through the first fuel filter. The flow through the first fuel filter is preferably determined by way of measuring changes in the level of fuel in the first fuel tank during a predetermined period of time, which level change is determined with a level sensor arranged in the first fuel tank. By reading the level sen- sor' s signals and thus determining how the fuel volume in the first fuel tank has changed during a certain time, the flow through the first fuel filter may be determined. Alternatively, the flow may be determined by way of measuring how long it takes to fill the first fuel tank with the first fuel pump. According to one aspect of the present invention, the pressure drop over the first fuel filter is calculated based on the rotational speed and/or power consumption of the first fuel pump. Depending on the characteristics of the first fuel pump, one revolution represents a certain amount of fuel being fed with the fuel pump, and the rotational speed of the first fuel pump (revolutions per time unit) thus represents a certain fuel flow. The rotational speed of the first fuel pump may be determined by way of measuring the voltage or power consumption of the first electric motor (and thus the first fuel pump). By measuring the first fuel pump's rotational speed and/or power consumption, the flow generated by the first fuel pump may be determined. At the same time, a verification that the first fuel pump functions as desired is obtained. By comparing the actual determined flow through the first fuel filter with the flow generated by the first fuel pump, the pressure drop over the first fuel filter may be calculated.
According to one aspect of the present invention, the pressure drop over the first fuel filter is calculated based on the temperature of the fuel in the first fuel tank. By detecting the temperature of the fuel in the first fuel tank, with a temperature sensor, the viscosity of the fuel may be determined. The viscosity of the fuel may impact the pressure drop over the first fuel filter, and by having regard to the viscosity the pressure drop may be calculated accurately and reliably.
According to one aspect of the present invention, the step of verifying that the calculated pressure drop for the first fuel filter is within the defined tolerance interval com- prises generating an error message when an error has been detected. The error message may suitably be presented in the vehicle to the driver, or in a diagnostic tool at a garage or a service place. Accordingly, the detected error may be made visible and addressed. The error message may be saved in a control device arranged in the vehicle. According to one aspect of the present invention, the step of verifying that the calculated pressure drop or the first fuel filter is within the tolerance interval comprises limiting the fuel supply to the combustion engine when an error has been detected. The fuel supply to the combustion engine may be limited by way controlling the first fuel pump in such a way that the fuel flow to the first fuel tank is limited. Alternatively, the second fuel pump is controlled in such a way that the fuel supply to the high pressure circuit is limited. By limiting the fuel supply to the combustion engine, the progress of the vehicle is limited as long as the error remains. When the error has been corrected, the limitation of the fuel supply suitably ceases. This prevents that the detected error relating to the fitting of the fuel filter is missed or ignored. This ensures, for example, that a fuel filter with poorer filtering properties than a reference fuel filter intended for the purpose is not used. Thus, a method is achieved to detect errors relating to fitting of a fuel filter in a fuel system, which method minimises the risk of operational disruptions. Alternatively, the start of the combustion engine is prevented when the calculated pressure drop is outside the tolerance interval, and errors relating to fitting thus have been detected. According to one aspect of the present invention, a fuel system is provided for a combustion engine, comprising a first fuel tank, a second fuel tank, a first fuel conduit arranged in connection with the first fuel tank and the second fuel tank, a first fuel pump, arranged to feed fuel from the second fuel tank to the first fuel tank through the first fuel conduit, a second fuel pump arranged to feed fuel from the first fuel tank to a high pressure circuit, and a first fuel filter arranged downstream of the first fuel pump and upstream of the second fuel pump. The fuel system also comprises a control device, arranged to provide a defined tolerance interval for a pressure drop over a reference fuel filter intended for this purpose, of controlling the first fuel pump to supply fuel from the second fuel tank to the first fuel tank via the first fuel filter, of calculating a pressure drop over the first fuel filter and determining whether an error has arisen when the first fuel filter was fitted, by way of controlling whether the calculated pressure drop is within the defined tolerance interval.
The defined tolerance interval may be fed manually into the control device, or alterna- tively it may be defined automatically in the control device. The tolerance interval may for example be stored in the control device when the vehicle is manufactured, and updated when the vehicle's software is updated, for example at service.
The control device is preferably arranged to calculate the pressure drop over the first fuel filter based on a flow through the first fuel filter. A level sensor is preferably arranged in the first fuel tank. The control device is suitably arranged in connection with the level sensor and the first fuel pump. Suitably the control device is arranged in connection with the first electric motor, which operates the first fuel pump. Furthermore, the control device is arranged in connection with the second electric motor, which operates the second fuel pump. In this manner, the control device may obtain information about the respective fuel pump. The control device may consist of a logic in a combustion engine control device, or alternatively the control device may consist of a separate control device, which is connected with the combustion engine control device.
The control device is suitably arranged to calculate the pressure drop over the first fuel filter based on the first fuel pump's rotational speed and/or power consumption. The control device is also suitably arranged to calculate the pressure drop over the first fuel filter based on the temperature of the fuel in the first fuel tank. The control device thus obtains signals from the level sensor, from the first and the second fuel pump and from a temperature sensor in the first fuel tank. The control device may also obtain signals from one or several other control devices in the vehicle, for example the combustion engine control device. Suitably, the first fuel tank is adapted so that it holds a smaller volume than the second fuel tank. This design entails a less bulky first fuel tank, which is easier to arrange inside a chassis. Thus, a non-bulky fuel system is achieved. Preferably, the first fuel tank holds 20-50 litres and the second fuel tank holds 300-1,000 litres. A third fuel tank may be arranged in connection with the second fuel tank.
Suitably, the second fuel pump is arranged in the first fuel tank. In this manner, the second fuel pump is protected from the environment and a natural cooling of the fuel in the first fuel tank is obtained. Alternatively, the first fuel pump and the first fuel filter are also arranged inside the first fuel tank.
According to one aspect of the present invention, a computer program is provided to detect errors in relation to the fitting of a fuel filter, wherein said computer program comprises program code to cause the control device or another computer connected to the control device to carry out the method steps according to the present invention.
Furthermore, a computer program product, comprising program code stored on a me- dium readable by a computer, is provided in order to perform the method steps according to the present invention, when said program code is executed in the control device or in another computer connected to the control device. Said program code may be stored in a non- volatile manner on said computer-readable medium. Other advantages of the invention are set out in the detailed description below.
BRIEF DESCRIPTION OF THE DRAWINGS
Below is a description of, as examples, preferred embodiments of the invention with reference to the enclosed drawings, in which:
Fig. 1 shows a schematic side view of a vehicle, which comprises a fuel system according to the present invention, Fig. 2 shows a coupling diagram for a fuel system according to the present invention, and
Fig. 3 shows a flow chart of a method to detect errors relating to the fitting of a fuel filter in a fuel system according to the present invention.
DETAILED DESCRIPTION OF AN EMBODIMENT ACCORDING TO THE IN¬
VENTION Fig. 1 shows a schematic side view of a vehicle 1, which vehicle comprises a fuel system 4 for a combustion engine 2 according to the present invention. The combustion engine 2 is connected to a gearbox 6, which is further connected to the driving wheels 8 of the vehicle 1 via a transmission. The vehicle also comprises a chassis 10.
Fig. 2 shows a coupling diagram for a fuel system 4 in a combustion engine 2 according to the present invention. The fuel system 4 comprises a high pressure pump 12, an accumulator in the form of a so-called common rail 14, and an injection system sche- matically displayed in the form of a fuel injector 16, which are arranged in the combustion engine 2 (the combustion engine 2 is displayed in Fig. 1) and which constitute the fuel system's 4 high pressure circuit 18. Alternatively, the common rail may be replaced by another form of an injection system, e.g. a piezo or a unit injection system. The fuel system 4 also comprises a first fuel tank 20, a second fuel tank 22, a first fuel pump 24, arranged to feed fuel from the second fuel tank 22 to the first fuel tank 20 through a first fuel conduit 26, a second fuel pump 28 arranged to feed fuel from the first fuel tank 20 to the high pressure circuit 18, and a first fuel filter 30 arranged downstream of the first fuel pump 24 and upstream of the second fuel pump 28. These components may be arranged at the vehicle's chassis 10 (the chassis 10 is displayed in Fig. 1). A second fuel filter 32 is arranged downstream of the second fuel pump 28 and upstream of the high pressure pump 12 in the fuel system 4. The first fuel filter 30 suitably consists of a pre-filter, and the second fuel filter 32 suitably consists of a main fuel filter. Further, the fuel system 4 comprises a fuel return conduit 34, through which fuel is returned from the fuel system's 4 high pressure circuit 18 back to the first fuel tank 20.
The two fuel tanks 20, 22 are in their respective top parts connected with a ventilation conduit 36, which communicates with the surrounding environment. The ventilation conduit 36 ensures that the pressure in the respective tanks 20, 22 is, and remains, sub- stantially the same and equal to the ambient air pressure, regardless of how much fuel is in the respective tanks. The first fuel tank 20 is adapted so that it holds a smaller volume than the second fuel tank 22, which second fuel tank 22 represents a main fuel tank. The first fuel pump 24 is, according to Fig. 2, arranged between the first fuel tank 20 and the second fuel tank 22. The first fuel pump 24 is operated by a first electric motor Ml. The second fuel pump 28 is operated by a second electrical engine M2 and is arranged inside the first fuel tank 20, and is thus protected from the environment and cooled by the fuel. Between the first fuel tank 20 and the second fuel tank 22 an overflow conduit 38 is arranged, so that fuel may be transported across from the first fuel tank 20 to the second fuel tank 22, if the first fuel tank 20 becomes overfilled. The second fuel pump's 28 main task is to feed the fuel from the first fuel tank 20, via a second fuel conduit 40, through the main fuel filter 32 and further to the high pressure circuit 18. The fuel is then fed, at a high pressure, to the common rail 14 and further along to the injection system 16 of the combustion engine 2. The first fuel filter 30 is preferably a fine mesh, water separating filter. In the second fuel tank 22, upstream of the first fuel pump 24, a coarse mesh sieve 42 is arranged, through which the first fuel pump 24 sucks fuel. The coarse mesh sieve 42 filters away particles above a certain predetermined size. The first fuel pump 24 then pressurises the fuel and feeds it through the first fuel filter 30, via the first fuel conduit 26, further along to the first fuel tank 20. The fuel in the first fuel tank 20 has thus passed both a coarse mesh sieve 42 and fine mesh pre-filter 30, which entails that the second fuel pump 28, which is arranged in the first fuel tank 20, is protected against impurities.
A control device 44 is arranged in connection with the first fuel pump and the second fuel pump. The control device 44 may be a computer with software suitable for this purpose. Another computer 46 may be connected to the control device 44. The control device 44 is arranged to provide a defined tolerance interval for pressure drops over the first fuel filter 30. Tolerance intervals are suitably based on a reference fuel filter intended for the purpose. That is to say, the defined tolerance interval is a tolerance interval for pressure drops, which should be obtained if a correct first fuel filter has been fitted correctly in the fuel system 4. The defined tolerance interval may be fed manually into the control device 44, or may be automatically defined in the control device 44. Furthermore, the control device 44 is arranged to control the first fuel pump 24 to feed fuel from the second fuel tank 22 to the first fuel tank 20, and to calculate a pressure drop over the first fuel filter 30. The control device 44 is also arranged to control that the calculated pressure drop over the first fuel filter 30 is within the defined tolerance interval, and thus to determine whether an error has arisen when the first fuel filter 30 was fitted. The control device 44 is also arranged to generate an error message if an error has been detected. With the help of the control device 44, the power consumption or the power output/voltage of the fuel pump's 24 electric motor Ml may be determined. With the power consumption and/or voltage the control device 44 may determine the rotational speed of the first fuel pump 24. The rotational speed may be used by the control device 44 to calculate the pressure drop over the first fuel filter 30.
A level sensor 48 is arranged in the first fuel tank 20, in order to identify the fuel level in the first fuel tank 20. The level sensor 48 is arranged in connection with the control device 44. The control device 44 may thus obtain information about level changes in the fuel volume of the first fuel tank 20 during a predetermined time period. With level changes the control device 44 may determine the flow through the first fuel filter 30, and based on the flow the control device 44 may calculate the pressure drop over the first fuel filter 30. During normal operation of the fuel system 4, the level sensor 48 may be used to determine when the fuel level in the first fuel tank 20 falls below a certain level, so that the first fuel pump 24 is controlled to feed fuel from the second fuel tank 22 to the first fuel tank 20.
Fig. 3 shows a flow chart of a method to detect errors relating to the fitting of a fuel filter in a fuel system 4 for a combustion engine 2 according to the present invention. The fuel system 4 is suitably adapted as described in Fig. 2, and thus comprises a first fuel tank 20, a second fuel tank 22, a first fuel conduit 26 arranged in connection with the first fuel tank 20 and the second fuel tank 22, a first fuel pump 24, arranged to feed fuel from the second fuel tank 22 to the first fuel tank 20 through the first fuel conduit 26, a second fuel pump 28, arranged to feed fuel from the first fuel tank 20 to a high pressure circuit 18 in the fuel system 4, and a first fuel filter 30 arranged downstream of the first fuel pump 24 and upstream of the second fuel pump 28. The method comprises the steps to:
a) define a tolerance interval for pressure drops over the first fuel filter 30;
b) control the first fuel pump 24 to feed fuel from the second fuel tank 22 to the first fuel tank 20 through the first fuel filter 30;
c) calculate a pressure drop over the first fuel filter 30; and
d) determine if an error has arisen when the first fuel filter 30 was fitted, by verifying whether the calculated pressure drop over the first fuel filter 30 is within the defined tolerance interval.
If the calculated pressure drop over the first fuel filter 30 is outside the defined tolerance interval, and an error has thus been detected, the error may be a result of incorrect fitting of the first fuel filter 30 or a wrong fuel filter having been fitted. The defined tolerance interval is preferably based on a reference fuel filter intended for the purpose. In this manner, a tolerance interval, within which the pressure drop ought to be placed is obtained, when a fuel filter for the intended purpose has been fitted correctly. The defined tolerance interval may also be based on the fuel type in the fuel system 4. Thus, the tolerance interval is suitably defined with consideration for the type of fuel filter that is intended for the purpose and/or the type of fuel that is intended for the purpose.
Preferably, the pressure drop over the first fuel filter 30 is calculated in step c) based on a flow through the first fuel filter 30. The flow through the first fuel filter 30 is preferably determined by way of measuring changes in the level of fuel in the first fuel tank 20 during a predetermined period of time, which level change is determined with a level sensor 48, arranged in the first fuel tank 20. By reading the level sensor's 48 signals and thus determining how the fuel volume in the first fuel tank 20 has changed during a certain time, the flow through the first fuel filter 30 may be determined. Al- ternatively, the flow may be determined by way of measuring how long it takes to fill the first fuel tank 20 with the first fuel pump 24. Preferably, the pressure drop over the first fuel filter 30 is also calculated based on the first fuel pump's 24 rotational speed and/or power consumption. The rotational speed of the first fuel pump 24 may be determined by way of measuring the voltage or power consumption of the first electric motor Ml (and thus the first fuel pump 24). By meas- uring the first fuel pump's 24 rotational speed and/or power consumption, the flow generated by the first fuel pump 24 may be determined. By comparing the actual determined flow through the first fuel filter 30 with the flow generated by the first fuel pump 24, the pressure drop over the first fuel filter 30 may be calculated. Preferably, the pressure drop over the first fuel filter 30 is also calculated based on the temperature of the fuel in the first fuel tank 20. By detecting the temperature of the fuel in the first fuel tank 20 with a temperature sensor (not displayed), the viscosity of the fuel may be determined. The viscosity of the fuel may impact the pressure drop over the first fuel filter 30, and by having regard to the viscosity the pressure drop may be calculated accurately and reliably.
Preferably the step d) comprises generating an error message when an error has been detected. The error message may suitably be presented in the vehicle 1 to the driver, or in a diagnostic tool at a garage or a service place. Accordingly, the detected error may be made visible and addressed. The error message may be saved in a control device 44, arranged in the vehicle 1.
Suitably the step d) comprises limiting the fuel supply to the combustion engine 2 when an error has been detected. Suitably, the fuel supply to the combustion engine 2 is limited by way of controlling the first fuel pump 24 in such a way that the fuel flow to the first fuel tank 20 is limited. Alternatively, the second fuel pump 28 is controlled in such a way that the fuel supply to the high pressure circuit 18 is limited. By limiting the fuel supply to the combustion engine 2, the progress of the vehicle 1 is limited as long as the error remains. When the error has been corrected, the limitation of the fuel supply suitably ceases. This ensures, for example, that a fuel filter with poorer filtering properties than a reference fuel filter intended for the purpose is not used. Thus, a method is achieved to detect errors relating to the fitting of a fuel filter in a fuel system 4 that minimises the risk of operational disruptions. Alternatively, step d) comprises the step of preventing start of the combustion engine 2 when the calculated pressure drop is outside the tolerance interval, and errors relating to fitting of a fuel filter have thus been detected.
Suitably steps a) - d) are carried out in connection with replacement of the first fuel filter 30 or fitting of the first fuel filter 30. In this manner, errors relating to the fitting of the fuel filter 30 may be detected at an early stage and the error may be addressed before serious consequences, such as operational disruptions, arise.
According to the invention, a computer program P is provided, stored in the control device 44 and/or the computer 46, which program may comprise procedures to detect errors relating to the fitting of a fuel filter according to the method described herein. The program P may be stored in an executable manner, or in a compressed manner, in a memory M and/or a read/write memory R.
The invention also relates to a computer program product, comprising program code stored in a medium readable by a computer, to perform the method steps specified above, when said program code is executed in the control device 44, or another computer 46 connected to the control device 44.
Said program code may be stored in a non- volatile way on said medium readable by a computer 46.
The components and features specified above may, within the framework of the invention, be combined between different embodiments specified.

Claims

Claims
1. Method for detection of errors relating to the fitting of a fuel filter in a fuel system (4) for a combustion engine (2), which fuel system (4) comprises a first fuel tank (20), a second fuel tank (22), a first fuel conduit (26) arranged in connection with the first fuel tank (20) and the second fuel tank (22), a first fuel pump (24), arranged to supply fuel from the second fuel tank (22) to the first fuel tank (20) via the first fuel conduit (26), a second fuel pump (28), arranged to supply fuel from the first fuel tank (20) to a high pressure circuit (18) in the fuel system (4), and a first fuel filter (30) arranged downstream of the first fuel pump (24) and upstream of the second fuel pump (28), characterised by the following steps:
a) defining a tolerance interval for pressure drops over the first fuel filter (30);
b) controlling the first fuel pump (24) to feed fuel from the second fuel tank (22) to the first fuel tank (20) through the first fuel filter (30);
c) calculating a pressure drop over the first fuel filter (30); and
d) determining if an error has arisen when the first fuel filter (30) was fitted, by verifying whether the calculated pressure drop is within the defined tolerance interval.
2. Method according to claim 1, wherein a detected error indicates that the first fuel filter (30) is incorrectly fitted or that the wrong type of fuel filter has been fitted.
3. Method according to claim 1 or 2, wherein the defined tolerance interval in step a) is based on a reference fuel filter intended for the purpose.
4. Method according to any of the previous claims, wherein the calculated pressure drop in step c) is based on a flow through the first fuel filter (30).
5. Method according to claim 4, wherein the flow through the first fuel filter (30) is determined by way of measuring changes in the level of fuel in the first fuel tank (20) during a predetermined period of time, which level change is determined with a level sensor (48), arranged in the first fuel tank (20).
6. Method according to any of the previous claims, wherein the calculated pressure drop in step c) is based on the rotational speed and/or power consumption of the first fuel filter (24).
7. Method according to any of the previous claims, wherein the calculated pressure drop in step c) is based on the temperature of the fuel in the first fuel tank (20).
8. Method according to any of the previous claims, wherein step d) also comprises generating an error message when an error has been detected.
9. Method according to any of the previous claims, wherein step d) also comprises limiting the fuel supply to the combustion engine (2) when an error has been detected.
10. Fuel system (4) for a combustion engine (2), comprising a first fuel tank (20), a second fuel tank (22), a first fuel conduit (26) arranged in connection with the first fuel tank (20) and the second fuel tank (22), a first fuel pump (24), arranged to feed fuel from the second fuel tank (22) to the first fuel tank (20) through the first fuel conduit (26), a second fuel pump (28), arranged to feed fuel from the first fuel tank (20) to a high pressure circuit (18) in the fuel system (4), and a first fuel filter (30) arranged downstream of the first fuel pump (24) and upstream of the second fuel pump (28), characterised in that a control device (44) is arranged to provide a defined tolerance interval for pressure drops over the first fuel filter (30), to control the first fuel pump (24) to supply fuel from the second fuel tank (22) to the first fuel tank (20) through the first fuel filter (30), to calculate a pressure drop over the first fuel filter (30) and to determine whether an error has arisen when the first fuel filter (30) was fitted, by verifying if the calculated pressure drop is within the defined tolerance interval.
11. Fuel system according to claim 10, wherein a level sensor (48) is arranged in the first fuel tank (20).
12. Fuel system according to claim 11, wherein a control device (44) is arranged in connection with the first fuel pump (24) and the level sensor (48).
13. Vehicle (1), characterised in that it comprises a fuel system (4) according to any of the claims 10-12.
14. Computer program (P) for detection of errors relating to the fitting of a fuel filter in a fuel system (4) for a combustion engine (2), wherein said computer program (P) comprises program code to cause an electronic control device (44), or another computer (46) connected to the electronic control device (44), to perform the steps according to any of claims 1-9.
15. Computer program product, comprising a program code stored in a medium readable by a computer, in order to perform the method steps according to any of claims 1- 9, when said program code is executed in an electronic control device (44) or in another computer (46) connected to the electronic control device (44).
PCT/SE2015/050883 2014-08-21 2015-08-20 Method to detect faults relating to mounting of fuel filters WO2016028211A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE112015003246.0T DE112015003246T5 (en) 2014-08-21 2015-08-20 Method for detecting errors relating to the assembly of fuel filters

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE1450969A SE538255C2 (en) 2014-08-21 2014-08-21 Method for detecting fuel filter mounting errors
SE1450969-9 2014-08-21

Publications (1)

Publication Number Publication Date
WO2016028211A1 true WO2016028211A1 (en) 2016-02-25

Family

ID=20299221

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2015/050883 WO2016028211A1 (en) 2014-08-21 2015-08-20 Method to detect faults relating to mounting of fuel filters

Country Status (3)

Country Link
DE (1) DE112015003246T5 (en)
SE (1) SE538255C2 (en)
WO (1) WO2016028211A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3396140A1 (en) * 2017-04-12 2018-10-31 Volkswagen Aktiengesellschaft Fuel pump module and method for controlling a fuel pump module

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1143232A1 (en) * 2000-04-07 2001-10-10 FILTERWERK MANN & HUMMEL GMBH Monitoring filter insertion
US6672147B1 (en) * 1998-12-14 2004-01-06 Magneti Marelli France Method for detecting clogging in a fuel filter in an internal combustion engine supply circuit
US7615151B2 (en) * 2007-01-25 2009-11-10 Cummins Filtration Ip Inc. Filter with installation integrity and magnetic flow-control

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6672147B1 (en) * 1998-12-14 2004-01-06 Magneti Marelli France Method for detecting clogging in a fuel filter in an internal combustion engine supply circuit
EP1143232A1 (en) * 2000-04-07 2001-10-10 FILTERWERK MANN & HUMMEL GMBH Monitoring filter insertion
US7615151B2 (en) * 2007-01-25 2009-11-10 Cummins Filtration Ip Inc. Filter with installation integrity and magnetic flow-control

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3396140A1 (en) * 2017-04-12 2018-10-31 Volkswagen Aktiengesellschaft Fuel pump module and method for controlling a fuel pump module

Also Published As

Publication number Publication date
SE1450969A1 (en) 2016-02-22
DE112015003246T5 (en) 2017-04-13
SE538255C2 (en) 2016-04-19

Similar Documents

Publication Publication Date Title
US7206720B2 (en) Computer-controlled auxiliary fuel tank system with multi-function monitoring system and user calibration capabilities
US20180245491A1 (en) Virtual Filter Condition Sensor
CN101281053B (en) System for detecting failures in fuel systems
CN102016266A (en) Method for determining air filter condition
US20160018288A1 (en) System for detecting an air filter condition, in particular for combustion engine
US20130312713A1 (en) Apparatus and Method of Determining a Leak Condition of a Fuel System
JP5182012B2 (en) Method for determining clogging life of fuel filter of internal combustion engine and internal combustion engine using the same
WO2016028211A1 (en) Method to detect faults relating to mounting of fuel filters
CN111936738A (en) Abnormality diagnosis device and abnormality diagnosis method
CN111886410B (en) Abnormality diagnosis device and abnormality diagnosis method
EP2312413B1 (en) Fuel filtration monitoring system
WO2014148986A1 (en) Fuel system for combustion engine and a method for exchanging a filter member in a fuel system
WO2014168562A1 (en) Method and device for detecting disruptions in a fuel system
US7710250B2 (en) System and method for verifying fuel cap engagement
US20170335788A1 (en) Method for checking a parameter correlating with a pressure in a pressure-dependent fluid-conveying system, control device and fluid-conveying system
EP2112480A1 (en) Device and method for the correct automatic reading of the engine oil level
SE1350358A1 (en) Combustion engine fuel system and a method for regulating a fuel system
SE539216C2 (en) Method and monitoring unit for detecting fuel system failures for an internal combustion engine
SE538983C2 (en) A method for determining the degree of clogging of a fuel filter in a fuel system
EP1739053B1 (en) Fuel vapour recovery system with temperature sensor and method therefor
JP5240415B2 (en) Rationality diagnosis device for alcohol concentration sensor
SE542773C2 (en) Method for diagonising a fuel filter, and control device therefore
WO2014168563A1 (en) Method and device for functional check of fuel supply conduit
SE540260C2 (en) Fuel system and method for indicating water in fuel by use of a conductivity sensor
WO2017003366A1 (en) Method and system for diagnosing a fuel system ii

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 15833432

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 112015003246

Country of ref document: DE

122 Ep: pct application non-entry in european phase

Ref document number: 15833432

Country of ref document: EP

Kind code of ref document: A1