US3718283A

US3718283A - Fuel injection nozzle units

Info

Publication number: US3718283A
Application number: US00085874A
Authority: US
Inventors: I Fenne
Original assignee: CAV Ltd
Current assignee: CAV Ltd
Priority date: 1969-11-12
Filing date: 1970-11-02
Publication date: 1973-02-27
Anticipated expiration: 1990-02-27
Also published as: DE2052311B2; DE2052311A1; ES193017Y; YU32512B; CA922189A; FR2069337A5; YU275570A; ES193017U; ZA707194B; GB1320920A

Abstract

A fuel injection nozzle unit which includes a valve member slidable under the action of fuel under pressure to allow a restricted flow of fuel through an orifice, the valve member being lifted further by the action of a piston to allow substantially un-restricted flow of fuel through the orifice.

Description

United States Patent 1191 1111 3,718,283

Fenne 1 1 Feb. 27, 1973 FUEL INJECTION NOZZLE UNITS [561 References Cited [75] Inventor: 1V0! Fenne, Greenford, England UNITED STATES PATENTS 1 Assigneel 'g- Limiwd Birmingham, 1,735,718 11/1929 Attendu ..239/533 g an [22] Filed: Nov. 2, 1970 Primary ExaminerLloyd L. King Attorney-Holman & Stern [21] App]. No.: 85,874

[57] ABSTRACT [30] Foreign Application Priority Data A fuel injection nozzle unit which includes a valve member slidable under the action of fuel under pres-- Nov. 12, I969 Great Brltam ..55,39l/69 sure to allow a restricted flow of fuel through an fice, the valve member being lifted further by the ac- [52] US. Cl ..239/533 tion of a piston to allow substantially umrestricted [5 Int. Cl. ..B05b flow of fuel oug e e [58] Field of Search ..239/533 2 Claims, 1 Drawing Figure mmgmwzmu 3 8,

INVENTOR' j 'q i ATTORNEYS FUEL INJECTION NozzLE UNITS BACKGROUND OF THE INVENTION This invention relates to fuel injection nozzle units of the kind intended to be mounted to direct fuel into a combustion chamber of an internal combustion engine and has for its object to provide such a nozzle unit in a form in which the initial rate of flow of fuel to the engine is at a restricted rate.

SUMMARY OF THE INVENTION A nozzle unit in accordance with the invention comprises in combination, an axially movable valve member, a seating with which said valve member cooperates to prevent the flow of fuel through an orifice of the nozzle unit, said valve member having a surface against which the fuel under pressure can act to move said valve member away from the seating, resilient means acting on said valve member to urge it into contact with the seating, a resiliently loaded stop for limiting the extent of movement of the valve member under the action of the fuel pressure acting on said surface, the valve member, when in contact with said stop, acting to permit fuel to flow through said orifice at a restricted rate and a resiliently loaded displaceable piston which is subjected to said fuel under pressure, said piston moving under the action of the fuel to limit the rise in pressure and when the fuel pressure has attained a predetermined value, acting to move the valve member and stop a further amount to permit substantially un-restructed flow of fuel through the orifice.

BRIEF DESCRIPTION OF THE DRAWINGS One example of a fuel injection nozzle unit in accordance with the invention will now be described with reference to the accompanying drawing in which the sole FIGURE shows a sectional side elevation of the nozzle unit.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawing, there is provided a body part in which is formed a cylindrical chamber 11 having an end wall 12. The exterior surface of the end wall is provided with a hollow projection 13 in which are formed orifices 14 through which, in use, fuel can flow to the combustion chamber of an internal combustion engine (not shown). Formed on the interior surface of the end wall is a conical seating 15 with which can co-operate, a complementarily shaped end surface 16 of a cylindrical valve member 16.

The valve member 16 is of stepped form and includes a narrower portion 16a which is adjacent the seating, and a wider intermediate portion 16b which is slidably accommodated within an annular piston 17. Moreover, defined at the junction of the wider and narrower portions, is a stop 25. The piston 17 is slidably mounted within the chamber 11 and is loaded towards the end wall 12 of the chamber by means of a coiled compression spring 18.

There is also provided a stop 19 which is resiliently loaded by means of a coiled compression spring 20 and the extent of movement of the stop 19 towards the end wall 12 is limited by a fixed stop 21 which passes through the stop 19 and has a head portion 22. Located intermediate the head portion 22 and the valve member 16 is a coiled compression spring 23 and the end portion of the stop 19 in the rest position of the nozzle and as is shown, extends beyond the end surface of the head portion 22 of the stop 21.

The chamber 11 in use, is in communication with a fuel pump 24 which is driven by the associated engine. As the pressure within the chamber 11 acts on the piston 17 and moves it against the action of the spring 18, this removes the force exerted by the spring 18 from the valve member 16 and this also moves against the action of the spring 23 into contact with the stop 19. This movement is sufficient to allow fuel to fiow through the orifices 14 at a restricted rate. As the fuel pressure within the chamber 11 increases, the piston 17 continues to move against the action of the spring 18 until it contacts a step 26 defined upon the valve member 16. During this movement, the piston 17' absorbs a large proportion of the pump displacement to prevent an excessive rise in fuel pressure owing to the restricted injection of fuel. As the fuel pressure increases beyond a predetermined value, the valve member 16 together with the stop 19 are moved against the action of the

springs

20 and 23 until the valve member contacts the head portion 22 of the stop. Fuel can now flow through the orifices 14 at a substantially unrestricted rate.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

l. A fuel injection nozzle unit of the kind intended to be mounted to direct fuel into a combustion chamber of an internal combustion engine and comprising in combination a body having a chamber and an end wall, said chamber being in communication with a fuel pump for delivering fuel thereto, a valve member mounted for axial movement in the chamber, a seating for the end wall with which said valve member cooperates to prevent the flow of fuel through an orifice of the end wall communicating with the combustion chamber said valve member having an abutment surface against which the fuel under pressure in the chamber can act to move said valve member axially away from the seating, a resiliently loaded stop located in the path of axial movement of the valve member for limiting the extent of movement of the valve member under the action of the fuel pressure acting on said abutment surface awayv from the seating, the valve member when in contact with said stop acting to permit fuel to flow through said orifice at a restricted rate and an axially displaceable annular piston located in the chamber, said valve member being slidably mounted within the annular piston, and resilient means operably related to said piston urging said piston and said valve member in the direction of the end wall to prevent fuel flow through the orifice, the annular piston resting upon the abutment surface on the valve member so that the resilient means serves to maintain the valve member in closed position on the seating, and upon the fuel pump supplying fuel to the chamber, the pressure acting on the piston removes the action of the resilient means so that the valve member engages the stop to allow fuel flow through the orifice at a restricted rate, and as the pressure of fuel delivered to the chamber increases, the pressure rise in the chamber is minimized by movement of the piston so that fuel continues to flow at a restricted rate through the orifice, a second abutment surface on the valve member spaced axially from the first abutment surface, and a fixed stop in the path of movement of the valve member located at a greater distance from the seating and the resiliently loaded stop, whereby as fuel pressure within the chamber increases, the piston continues its movement against the action of the resilient means away from the end wall until it engages the second abutment surface on the valve member so that the piston prevents an excessive rise in fuel pressure and upon the fuel pressure increasing beyond a predetermined value, the valve member and resiliently loaded stop move together, until the valve member engages the fixed stop to permit substantially unrestricted flow of fuel through the orifice.

2. A fuel injection nozzle unit of the kind intended to be mounted to direct fuel into a combustion chamber of an internal combustion engine and comprising in combination, a body having a chamber and an end wall, a valve member axially movable in the chamber, a seating in the end wall with which the valve member cooperates to prevent fuel flow through an orifice of the end wall communicating with the combustion chamber, means supplying fuel under pressure to the chamber, said valve member having a surface against which the fuel under pressure in the chamber serves to move the valve member away from the seating, a resiliently loaded stop in the path of movement of the valve member to limit the extent of movement of the valve member under the action of the fuel pressure in the chamber acting on said surface, the valve member when in contact with the stop, serving to permit fuel to flow through the orifice at a restricted rate, and a resiliently loaded displaceable annular piston within the chamber and surrounding said valve member, said piston resting on said surface of the valve member when no fuel is supplied to the chamber so that the resilient loading of the piston serves to maintain the valve member in closed position on the seating, said annular piston moving under the action of fuel in the chamber to limit a rise in pressure and upon the fuel pressure attaining a predetermined value, acting to move the valve member and stop a further amount to permit substantially unrestricted fuel flow through the orifice.

Claims

1. A fuel injection nozzle unit of the kind intended to be mounted to direct fuel into a combustion chamber of an internal combustion engine and comprising in combination a body having a chamber and an end wall, said chamber being in communication with a fuel pump for delivering fuel thereto, a valve member mounted for axial movement in the chamber, a seating for the end wall with which said valve member cooperates to prevent the flow of fuel through an orifice of the end wall communicating with the combustion chamber said valve member having an abutment surface against which the fuel under pressure in the chamber can act to move said valve member axially away from the seating, a resiliently loaded stop located in the path of axial movement of the valve member for limiting the extent of movement of the valve member under the action of the fuel pressure acting on said abutment surface away from the seating, the valve member when in contact with said stop acting to permit fuel to flow through said orifice at a restricted rate and an axially displaceable annular piston located in the chamber, said valve member being slidably mounted within the annular piston, and resilient means operably related to said piston urging said piston and said valve member in the direction of the end wall to prevent fuel flow through the orifice, the annular piston resting upon the abutment surface on the valve member so that the resilient means serves to maintain the valve member in closed position on the seating, and upon the fuel pump supplying fuel to the chamber, the pressure acting on the piston removes the action of the resilient means so that the valve member engages the stop to allow fuel flow through the orifice at a restricted rate, and as the pressure of fuel delivered to the chamber increases, the pressure rise in the chamber is minimized by movement of the piston so that fuel continues to flow at a restricted rate through the orifice, a second abutment surface on the valve member spaced axially from the first abutment surface, and a fixed stop in the path of movement of the valve member located at a greater distance from the seating and the resiliently loaded stop, whereby as fuel pressure within the chamber increases, the piston continues its movement against the action of the resilient means away from the end wall until it engages the second abutment surface on the valve member so that the piston prevents an excessive rise in fuel pressure and upon the fuel pressure increasing beyond a predetermined value, the valve member and resiliently loaded stop move together until the valve member engages the fixed stop to permit substantially unrestricted flow of fuel through the orifice.