EP0723077A1

EP0723077A1 - Hydraulically-actuated electronically-controlled fuel injector system

Info

Publication number: EP0723077A1
Application number: EP95308861A
Authority: EP
Inventors: Gregory W. Hefler; Ronald D. Sinogle
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 1995-01-17
Filing date: 1995-12-06
Publication date: 1996-07-24
Also published as: JPH08232798A

Abstract

A hydraulically-actuated electronically-controlled fuel system (10,130,310,410) includes an electronic control module (12,132,312,412) and an actuator portion (22,142,320,420) in fluid communication with a source of high pressure actuating fluid (18,138,313,414). The actuator portion (22,142,320,420) has a solenoid (50,172,172,456) electrically connected with the electronic control module responsive to electrical signals therefrom as well as a poppet valve (58,184,184,458) operably displaced by the solenoid between a first position and a second position. The fuel system (10,130,310,410) also includes an intensification portion (22,146,324,422) having a cylinder (77,210,210,210) with a piston (78,212,212,212) slidably disposed therein which defines in part a pressurization chamber (74,206,206,206) in fluid communication with the actuator portion (22,142,320,420). The pressurization chamber (74,206,206,206) is pressurized by high pressure actuating fluid when the poppet valve (58,184,184,458) is in the second position. The intensification portion (22,146,324,422) also has a plunger (82,216,216,216) defining in part a fuel pressurization chamber (86,220,220,220) which is at least operably engaged by the piston. The fuel system (10,130,310,410) also includes a nozzle portion (24,146,324,422) disposed in the engine head which has a nozzle tip (120,246,246,246) with a valve check (112,248,248,248) slidably disposed therein. The nozzle tip (120,246,246,246) and valve check (112,248,248,248) cooperatively define an annual discharge chamber (118,254,254,254) in fluid communication with the fuel pressurization chamber. The fuel system (10,130,310,410) is configured so that at least one of the actuator portion (22,142,320,420) and the intensification portion (22,146,324,422) are axially offset from the nozzle portion (24,146,324,422).

Description

The present invention relates generally to fuel injection systems and, more particularly, to hydraulically-actuated electronically-controlled fuel injection systems.
An example of a high pressure hydraulically-actuated electronically-controlled fuel injection system is shown in US-A-5,191,867. This type of fuel injector provides precise control of fuel injection timing and quantity. These advantages are particularly beneficial in fuel injection systems used with diesel cycle engines. Fuel injectors of the type disclosed by Glassey et al. are longitudinally configured with substantially all of the components arrayed on a single axis. This includes an actuator portion with an electromagnetic solenoid which operably displaces a poppet valve for selectively pressurizing fuel in the injector with actuation of the solenoid. The injector also has an intensification portion with a piston acted on by the pressurized actuating fluid, the piston in turn acting against a smaller diameter plunger which pressurizes the fuel. Lastly, the injector has a nozzle portion which receives the pressurized fuel. A valve check slidably disposed in the nozzle portion is slidably displaced by highly pressurized fuel to open an injection orifice through which the fuel passes.
As fuel injectors are typically mounted in an engine head which is at a top portion of the engine, the resultant longitudinal, or axial, length of the fuel injector can make it difficult to package in some vehicle applications.
It is desired to provide a high pressure hydraulically-actuated electronically-controlled fuel injection system which can be packaged in confined areas unable to accommodate a unitary fuel injector of the type shown by US-A-5,191,867.
In one aspect of the present invention, a hydraulically-actuated electronically-controlled fuel system includes an electronic control module and an actuator portion in fluid communication with a source of high pressure actuating fluid. The actuator portion has a solenoid electrically connected with the electronic control module responsive to electrical signals therefrom. A poppet valve of the actuator portion is operably displaced by the solenoid between a first position blocking high pressure actuating fluid and a second position communicating high pressure actuating fluid therepast. The fuel system also includes an intensification portion having a cylinder with a piston slidably disposed therein which defines in part a pressurization chamber in fluid communication with the actuator portion. The pressurization chamber is pressurized by the actuator portion when the poppet valve is in the second position. The intensification portion also has a plunger defining an end of a fuel pressurization chamber and which is at least operably engaged by the piston. A working area of the piston is greater than a working area of the plunger, with the plunger operably pressurizing fuel to a pressure greater than the pressure of the hydraulically actuating fluid. The fuel system also includes a nozzle portion disposed in the engine head which has a nozzle tip with a valve check slidably disposed therein. The nozzle tip and valve check cooperatively define an annual discharge chamber in fluid communication with the fuel pressurization chamber. The valve check is biased to a first position engaging a seat of the tip by a spring. The valve check is biased to a second position spaced from the seat and exposing an injection orifice by pressurized fuel acting thereon when the solenoid is in the second position. The fuel system is configured so that at least one of the actuator portion and the intensification portion are axially offset from the nozzle portion.
In one particular aspect of the present invention, a unitary combination of the actuator portion and the intensification portion are offset from the nozzle portion.
In yet another aspect of the present invention, the actuator portion is offset from a unitary intensification portion and nozzle portion disposed in the engine head.
In yet another aspect of the present invention, the actuator portion is offset from the unitary intensification portion and nozzle portion and the actuator portion, as well as the unitary intensification and nozzle portion, are both mounted in the engine head.
In the accompanying drawings:

Figure 1 is a schematic illustration of a first embodiment of a fuel system.
Figure 2 is a diagrammatic enlarged cross sectional view of a unitary actuator and intensification portion of a fuel injection system.
Figure 3 is a diagrammatic enlarged cross sectional view of a nozzle portion of a fuel injection system.
Figure 4 is a schematic illustration of a second embodiment of the fuel injection system.
Figure 5 is a diagrammatic enlarged cross sectional view of an actuator portion of the fuel injection system of Figure 4.
Figure 6 is a diagrammatic enlarged cross sectional view of a unitary intensification and nozzle portion of the fuel injection system of Figure 4.
Figure 7 is a schematic illustration of a third embodiment of the fuel injection system.
Figure 8 is a schematic illustration of a fourth embodiment of a fuel injection system.
Figure 9 is a diagrammatic enlarged cross sectional view of an actuator portion of the fuel injection system of Figure 8.

An exemplary fuel injection system 10 is shown in Figure 1. The system 10 includes an electronic control module (ECM) 12, a manifold block 14, an actuating fluid high pressure pump 16, an actuating fluid supply system 18, and a fuel supply system 20. The fuel injection system 10 also includes an integral actuator/intensification portion 22 and a separate and axially offset nozzle portion 24 of a nonunitized fuel injector. A high pressure fuel line 25 connects the integral actuator/intensification portion 22 with the nozzle portion 24. The aggregation of the portions 22 and 24 is commonly known as a fuel injector.
The nozzle portion 24 is disposed in an engine head 26. The engine head 26 has a fuel return channel 27.
An ECM wiring harness 28 electrically connects the ECM 12 with the integral actuator/intensification portion 22. A manifold cover 29 is placed over a side of the manifold block 14 from which the integral actuator/ intensification portion 22 extends.
The manifold block 14 defines an actuating fluid manifold 30 or channels therein, connected to a high pressure actuating fluid line 32 from the actuating fluid high pressure pump 16 providing fluid communication therebetween. The pump 16 is shown fixed to the manifold 14, but could potentially be formed integrally with the manifold to eliminate the need for the connecting fluid line 32.
The manifold block 14 also defines a fuel manifold 34, or fuel channels therein. The fuel supply system 20 is connected to the fuel manifold 34.
The fuel supply system 20 also includes the fuel line 36 which extends from a fuel sump 38 to a fuel pump 39, and to a fuel filter 40. The fuel line 36 then connects to the manifold block 14.
The actuating fluid supply system 18 includes an actuating fluid low pressure (intake) line 41 extending from an actuating fluid sump 42, to an actuating fluid low pressure pump 44, to an actuating fluid cooler 46, to an actuating fluid filter 48, and finally to the high pressure pump 16.
Additional detail of the integral actuating/intensification portion 22 is shown in Figure 2.
A solenoid assembly 50 has an electrical connector 51 affixed thereto engaged by the wiring harness 28. The solenoid assembly 50 has a fixed stator 52 and a movable armature 54 which operably translates along a longitudinal axis 56. The movable armature 52 is attached by a fastener 57 to a poppet valve 58. The poppet valve 58 is slidably disposed in a valve body 60. A poppet spring 62 disposed between the valve body and the poppet valve 58 biases the poppet valve 58 to a first or closed position against an annular seat 64 on the valve body 60. When the solenoid assembly 50 is energized, the movable armature 54 is displaced toward and against an annular seat on a sleeve 67. An actuating fluid inlet passage 68 in the valve body 60 is in fluid communication with the actuating fluid manifold 30. The inlet passage 68 passes through the valve body 60 at a point below the seat 64 on the body 60.
A drain passage 70 proximate to the solenoid assembly 50 is provided for the actuating fluid.
An intermediate passage 72 provides fluid communication between the inlet passage 68 and a piston pump chamber 74 when the poppet valve 58 is in the second position.
The piston pump chamber 74 defines a piston seat 76 at an end of a piston bore 77, and is in part defined by a piston 78 slidably disposed in the piston bore 77. The piston has a piston working area established by its diameter and also has an elongated skirt 79 extending down into the bore 77. A piston return spring 80 is disposed against the piston inside the skirt 79. Also disposed in part within the piston skirt 79 is a plunger 82 of a plunger working area established by the diameter of the plunger. The diameter of the plunger 82 is smaller than the diameter of the piston 78 hence, the plunger working area is less than the piston working area. The piston cylinder terminates at a barrel 84. The barrel 84 has a bore therethrough in which the plunger 82 is slidably disposed. The plunger and barrel cooperatively define a fuel pressurization chamber 86 at an end of the plunger 82. The barrel 84 has a one way fuel inlet valve 88 which permits entry of fuel into the fuel pressurization chamber 86. A first case 90 surrounds the barrel 84 and joins it to the valve body 60. The first case 90 also defines an annular void 91 around the barrel 84. There is a fuel inlet opening 92 in the first case in fluid communication with the annular void. A first fitting 93 connects to and seals against the first case 90 and the barrel 84.
The high pressure fuel line 25 extends from the first fitting 93 to a second fitting 94.
The second fitting 94 connects to the nozzle portion 24 shown in Figure 3. A second case 96 holds together several axially adjacent components comprising the nozzle portion 24. Adjacent the second fitting 94 is an intermediate plate 98 with an aperture 99 therethrough. Adjacent the intermediate plate 98 is a check stop 100. In the check stop 100 is a one way valve 102 of the type disclosed in U.S. Patent No. 5,287,838 issued to Wells on 22 February 1994, which is aligned with the aperture in the intermediate plate 98. A discharge passage 104 extends from the one way valve 102 to a side opposite the intermediate plate 98, and continues in a sleeve 106 adjacent the check stop 100. The sleeve 106 also defines a spring chamber 108 therein. A relief passage 109 passes through the sleeve from the spring chamber 108 and through the second case 96. A nozzle tip 110 is adjacent the sleeve 106. A valve check 112 is slidably disposed in the nozzle tip and in part disposed in the spring chamber 108 of the sleeve 106. A valve check return spring 114 is disposed in the spring chamber 108 between a spring seat 115 of the valve check 112 and the check stop 100. The discharge passage 104 extends from the sleeve 106 into the nozzle tip 110, passing into a cardioid chamber 116 of the nozzle tip.
The cardioid chamber 116 surrounds a portion of the valve check 112, and extends into an annular discharge chamber 118 surrounding a lower portion of the valve check 112. A tip 120 of the valve check 112 is biased against a valve seat 122 of the nozzle tip 110 by the valve check return spring 114. The tip 120 of the valve check, when engaging the valve seat 122, blocks an injection orifice 124 at an end of the nozzle tip 110.
Figure 4 illustrates a second embodiment of a hydraulically-actuated electronically-controlled fuel injection system 130.
This system 130 similarly has an electronic control module (ECM) 132, a manifold block 134, actuating fluid high pressure pump 136, an actuating fluid supply system 138, and a fuel supply system 140.
The second embodiment of the system 130, is distinguished over the first embodiment of the system 10 in that it has a separate actuator portion 142 connected by a high pressure actuating fluid line 144 to an integral intensification/nozzle portion 146 which is disposed in an engine head 148. The actuator portion 142 is axially offset from the integral intensification/nozzle portion 146.
Low pressure fuel is supplied to the intensification/nozzle portion 146 through a fuel channel 150 in the head 148.
An ECM wiring harness 152 connects the ECM 132 with the actuator portion 142. A manifold cover 153 is placed over a side of the manifold block 134 from which the actuator portion 142 extends. Channels 154 within the manifold block 134 receive high pressure actuating fluid from a high pressure actuating fluid feedline 156 connected to the actuating fluid high pressure pump 136.
The fuel supply system 140 includes a fuel line 157 extending from a fuel sump 158 to a fuel pump 160, and a fuel filter 162, and connecting to the engine head 148 to communicate fuel to the fuel channel 150.
The actuating fluid supply system 138 includes an actuating fluid low pressure line 163 extending from an actuating fluid sump 164, to an actuating fluid low pressure pump 166, to an actuating fluid cooler 168 and to an actuating fluid filter 170, then connecting with the high pressure pump 136.
The actuator portion 142 has a solenoid assembly 172 disposed at one end. The solenoid assembly 172 has an electrical connector 174 disposed on a side thereof engaged by the wiring harness 152. The solenoid 172 also has a fixed stator assembly 176 and a movable armature 178. The movable armature is operably displaced along an a longitudinal axis 180. A fastener 182 fixes a poppet valve 184 to the movable armature 178 for movement therewith. The poppet valve 184 is slidably disposed within a valve body first part 186. A poppet spring 188 biases the valve 184 against an annular seat of the valve body. The configuration of the poppet valve and its relation to the annular seat on the valve body 186 and a similar seat on a sleeve 189 is essentially the same as in the first embodiment of the system 10. An actuating fluid inlet passage 190 is in fluid communication with the channels 154 in the manifold block 134 and directs fluid to the poppet valve 184 where it is operably blocked by engagement between the poppet valve 184 and the annular seat of the valve body 186. When the poppet valve 184 is lifted from the annular seat of the valve body 186, pressurized actuating fluid is communicated to the intermediate passage 192. The intermediate passage 192 extends from the valve body first part 186 into and through an adjacent valve body second part 194. The valve body first part 186 and valve body second part 194 are joined together by a first case 196. A first fitting 198 at an end of the first case 196 connects the high pressure actuating fluid line 144 with the intermediate passage 192.
The high pressure actuating fluid line 144 extends to a second fitting 200 of the integral intensification/nozzle portion 146. A second case 202 of the integral intensification/nozzle portion holds a plurality of adjacent components together in their desired positions. A piston cylinder 204 is adjacent the second fitting 200. The piston cylinder 204 in part defines a piston pump chamber 206 with a piston seat 208 therein. The piston cylinder 204 defines a bore 210 extending from the piston pump chamber 206. A piston 212 is slidably disposed in the piston bore 210. The piston 212 has a longitudinal skirt extending away from the piston chamber 206 and the piston seat 208. A piston return spring 214 is disposed within the piston skirt, as is a plunger 216. The plunger 216 is at least operably engaged by the piston 212, and has an end portion disposed in a bore of a barrel 218. The barrel 218 and plunger 216 cooperatively define a fuel pressurization chamber 220. The second case 202 surrounds the barrel, defining an annular fuel passage 222 therearound. A fuel port 224 passes through the second case 202 into the annular fuel passage 222.
An intermediate plate 226 is disposed adjacent the barrel 218. The intermediate plate 226 has an inlet aperture 228 and an outlet aperture 230.
A check stop 232 is adjacent the intermediate plate 226. A one way inlet valve 234 of the ball check type is disposed in the check stop 232 and aligned with the inlet aperture 228 of the intermediate plate 226. A groove in the check stop 232 between the inlet valve 234 and an outside of the check stop defines an edge filter 235. A one way discharge valve 236 of the type disclosed in the patent to Wells is aligned with the outlet aperture 230 of the intermediate plate 226. A discharge passage 238 extends from the discharge valve 236 to a side of the check stop 232 opposite the intermediate plate 226.
A sleeve 240 adjacent the check stop 232 has a central bore therethrough defining a spring chamber 242. The discharge passage 238 extends from the check stop 232 through the sleeve 240 parallel to the spring chamber 242. A relief passage 244 passes from the spring chamber 242 to an outside of the sleeve 240.
A nozzle tip 246 is disposed adjacent the sleeve 240. A valve check 248 is slidably disposed in the nozzle tip 246, and has a portion extending into the spring chamber 242 of the sleeve 240. A valve check return spring 250 is disposed in the spring chamber 242 between the valve check 248 and the check stop 232.
The nozzle tip 246 also defines a cardioid chamber 252 therein fluidly connected with the discharge passage 238. The valve check 248 extends through the cardioid chamber 252 and with the nozzle tip 246 defines an annular discharge chamber 254 therearound. The valve check return spring 250 biases the valve check 248 to a first position in which a tip 256 of the valve check 248 engages a valve seat 258 of the nozzle tip 246. In the first position, the valve tip 256 blocks an injection orifice 260 through an end of the nozzle tip 246. In a second position, the tip 256 is spaced from the seat 258.
A third embodiment of a hydraulically-actuated electronically-controlled fuel injection system 310 is illustrated in Figure 7. The system 310 includes an electronic control module 312, a high pressure actuating fluid supply system 313, a hydraulic actuating fluid manifold 314, a first high pressure actuating fluid line 315 between the high pressure supply system 313 and the hydraulic actuating fluid manifold 314. The system 310 additionally includes a mini-block 316 connected by a second high pressure actuating fluid line 318 to the hydraulic actuating fluid manifold 314. Also in the system 310 is an actuator portion 320 substantially the same as the actuator portion 142 of the second embodiment of the system 130. A third high pressure actuating fluid line 322 provides fluid communication between the actuator portion 320 and an integral intensification/nozzle portion 324 mounted in an engine head 326. The integral intensification/nozzle portion 324 is substantially the same as the integral intensification/nozzle portion 146 of the second embodiment of the system 130 as shown in Figure 6. The engine head 326 defines a fuel channel 328 therein. Connected to the fuel channel 328 is a fuel supply system 330. A fuel line 331 of the fuel supply system 330 extends from a fuel sump 332 to a low pressure fuel pump 334, to a fuel filter 336 and to the engine head 326.
An ECM wiring harness 338 extends from the ECM to the actuator portion 320.
The fluid supply system 313 includes an actuating fluid low pressure line 340 extending from an actuating fluid sump 342 to an actuating fluid low pressure pump 343 to an actuating fluid cooler 344, to an actuating fluid filter 346 and to an actuating fluid high pressure pump 348. The first high pressure actuating fluid line 315 extends from the high pressure pump 348 to the mini block 316.
A fourth embodiment of a hydraulically-actuated electronically-controlled fuel injection system 410 is illustrated in Figure 8. The system 410 includes an electronic control module 412, a high pressure actuating fluid supply system 414, a fuel supply system 416, and an engine head 418. Also included are an actuator portion 420 substantially similar to the actuator portion 142 of the second embodiment of the system 130, and an integral intensification/nozzle portion 422 substantially similar to the integral intensification/nozzle portion 146 of the second embodiment 130. A valve cover 423 is disposed over the head 418, covering both the actuator portion 420 and the integral intensification/nozzle portion 422.
An ECM wiring harness 424 connects the ECM 412 with the actuator portion 420.
A fuel line 426 of the fuel supply system 416 connects with the engine head 418 in fluid communication with a fuel channel 428 in the engine head 418. The fuel line 426 extends from a fuel sump 430 to a fuel pump 432 and a fuel filter 434 and to the engine head 418.
A first high pressure actuating fluid channel 436 in the engine head 418 is connected with a high pressure actuating fluid line 438 which extends to a high pressure actuating fluid pump 440. The high pressure actuating fluid pump 440 is supplied with actuating fluid by a low pressure actuating supply line 442 which extends from an actuating fluid sump 444 to an actuating fluid low pressure pump 446 to an actuating fluid cooler 448 to an actuating fluid filter 450 and to the high pressure actuating fluid pump 440. A second high pressure actuating fluid channel 452 within the engine head extends from the actuator portion 420 to the integral intensification/nozzle portion 422. The integral intensification/nozzle portion 422 is distinguished over the integral intensification/ nozzle portion 146 of the second embodiment 130 by the presence of a fuel entry aperture 454 through an upper portion of the piston cylinder and a lack of a second fitting.
The actuator portion 420 is illustrated in greater detail in Figure 9. As in the other embodiments of the fuel injection system, there is a solenoid assembly 456 which operably displaces a poppet valve 458 slidably disposed in a valve body 460. An actuating fluid inlet passage 462 directs fluid to the poppet valve as in the other embodiments. However, the intermediate passage 464 is reconfigured to direct or to communicate fluid through a side of the valve body 460 and into the second high pressure actuating fluid channel 452 for communication of the high pressure actuating fluid to the integral intensification/nozzle portion 422.

Industrial Applicability

In the first embodiment 10, actuating fluid is drawn through the actuating fluid low pressure line 41 from the sump 42 by the actuating fluid low pressure pump 44. The fluid passes from the pump through the cooler 46 and then through the filter 48. The filtered actuating fluid then enters the high pressure actuating fluid pump 16.
Highly pressurized actuating fluid leaves the high pressure pump 16 through high pressure actuating fluid line 32 to the actuating fluid manifold or channels 30 of the manifold block 14. The actuating fluid is pressurized to a selected pressure, for example, 23 MPa (3335 psi).
Fuel is drawn through the fuel line 36 from the sump 38 by the fuel pump 39. Fuel passes from the pump 39 through the fuel filter 40 and into the fuel manifold 34 of the manifold block 14.
Fuel in the fuel manifold 34 passes through the fuel inlet opening 92 in the first case 90, filling the annular void 91. The low pressure fuel from the annular void 91 unseats the fuel inlet valve 88 in the barrel 84, entering the fuel pressurization chamber 86.
Actuating fluid from the actuating fluid manifold 30 travels up the inlet passage 68. With the poppet valve 58 in the first position, there is a substantial pressure differential across the annular seat 64 on the body 60 with the highly pressurized fluid in the inlet passage 68 on one side, and relatively low pressure fluid on the opposite side. Pressure in the intermediate passage 72 and the piston pump chamber 74 equals the relatively low pressure because this side of the valve is open to drain.
The poppet valve is displaced to the second position by the movable armature 54 of the solenoid 50 being displaced in response to an electrical signal from the ECM 12. When the poppet valve 58 moves to the second position, engaging the annular seat 64 on the sleeve 67 and unseating from the annular seat 64 on the body 60, fluid in the intermediate passage 72 and the piston pump chamber 74 is rapidly pressurized by the highly pressurized fluid from the inlet passage 68.
With the increased pressure in the piston pump chamber 74, the piston 78 is displaced downward from the piston seat 76 by the actuating fluid, overcoming the piston return spring 80. The piston 78 in turn forces the plunger 82 further into the bore in the barrel 84, thereby pressurizing fuel in the fuel pressurization chamber 86. Because the working area of the piston 78 is greater than the working area of the plunger 82, the resultant pressure of the fuel in the fuel pressurization chamber 86 is greater than the pressure of the hydraulic actuating fluid in the piston pump chamber 74 by a ratio approximately equal to the area of the piston divided by the area of the plunger. An exemplary ratio of areas is approximately 7, resulting in a fuel pressure of approximately 161 MPa (23350 psi) when the selected hydraulic pressure is about 23 MPa (3335 psi).
Pressurization of fuel in the pressurization chamber 86 results in pressurization of fuel disposed in the high pressure fuel line 25 which provides fluid communication between the integral actuator/intensification portion 22 and the nozzle portion 24. Highly pressurized fuel resultantly impinges against the intermediate plate 98, passing through the aperture 99, flowing past the one way valve 102 and into the discharge passage 104.
Highly pressurized fuel in the discharge passage 104 is communicated to the cardioid chamber 116 and the connecting annular discharge chamber 118. Fuel in the annular discharge chamber and cardioid chamber acts on the exposed area of the valve check therein to displace it upward, overcoming the return spring 114 and unseating the tip 120 of the valve check 112 from the seat 122 of the nozzle tip 110. Any fluid trapped in the spring chamber 108 is free to move through the relief passage 109, thereby preventing hydraulic locking of the valve check 112. Once the valve check 112 is unseated, the fuel flows through the exposed injection orifice 124.
Injection is terminated by the ECM which deenergizes the solenoid assembly 50, with the poppet spring 62 returning the poppet 58 to the first position and interrupting the communication of pressurized fluid beyond the annular seat 64 on the body. Pressure of the hydraulic actuating fluid in the piston pump chamber 74 and the intermediate passage 72 is relieved by flowing past the annular seat 64 on the sleeve and out through the drain passage 70. With the fluid pressure against the piston 78 relieved, the return spring 80 forces the piston 78 against the piston seat 76. Fuel pressure also decreases, with the upward return of the plunger. The check return spring 114 forces the tip 120 of the valve check 112 against the valve seat 122 of the nozzle tip 110, again closing off the orifice 124. Fuel moves from the annular void 91 past the one way fuel inlet valve 88 and into the fuel pressurization chamber 86 to compensate for volume loss due to upward movement of the plunger 82.
The advantage of this configuration over an injection system having unitary injectors is in the space saved at the engine head by having the injector portions 22 and 24 axially offset from one another. In this first embodiment, only the nozzle portion 24 is disposed in the engine head 26. The manifold block 14 with the integral actuator/intensification portion 22 can be located at essentially any convenient underhood location. Of the four embodiments disclosed herein, this one offers the most space saving at the engine head, as only the nozzle portion 24 is disposed in the head 26.
The second embodiment of the invention operates in substantially the same manner as described above for the first embodiment. The distinction is that instead of communicating highly pressurized fuel between the manifold block and the engine head, pressurized actuating fluid is communicated therebetween.
Highly pressurized hydraulic actuating fluid is directed to actuating fluid manifold 154 of the manifold block 134 in the same manner as is done in the first embodiment.
Fuel, however, is communicated not to the manifold block 134, but to the engine head 148. When the poppet valve 184 is in the second position, and pressure is communicated from the inlet passage 190 to the intermediate passage 192, pressure is communicated through fluid in the high pressure actuating fluid line 144 to the piston pump chamber 206. Fuel in the fuel pressurization chamber 220 passes through the outlet aperture 230 in the intermediate plate 226 and past the one way discharge valve 236 to enter the discharge passage 238. Pressurized fuel in the cardioid chamber 252 and the annular discharge chamber 254 displaces the valve check 248 from the valve seat 258, exposing the injection orifice 260 and passing therethrough to start injection.
When the poppet valve 184 is returned by the solenoid 172 to the first position, with the orifice 260 closed off, the plunger 216 withdraws, with replacement fuel being drawn into the fuel pressurization chamber 220 through the inlet aperture 228 of the intermediate plate 226. Fuel passes from the annular fuel passage 222 through the edge filter 235, past the one way inlet valve 234, through the inlet aperture 228 and into the fuel pressurization chamber.
Although this embodiment does not offer quite the space savings at the engine head provided by the first embodiment, it still offers a significant improvement in space saving at the engine head 148 over an injection system with unitary injectors. Additionally, this second embodiment provides a shorter path between the fuel pressurization chamber 220 and the injector orifice 260 than does the first system embodiment 10 which simplifies or minimizes fuel handling dynamics and its effect on injection.
The third embodiment of the fuel injection system as shown in Figure 7 operates essentially the same as the second embodiment of the fuel injection system 130, except that the manifold block 134 of the second embodiment is broken up into a plurality of mini blocks 318 in the present embodiment. Each of these mini blocks 318 receives high pressure actuating fluid from the hydraulic actuating fluid manifold 314 which is connected to the high pressure pump 348.
The principal advantage of this configuration is that there is no need to locate a single large manifold block near the engine as there is with the first two embodiments. The plurality of mini blocks 316 can be located separately in any convenient underhood location.
The fourth embodiment is readily distinguished from the first three embodiments in that the actuator portion 420, as well as the integral intensification/nozzle portion 422 are both disposed in the engine head 326. This eliminates any need for exterior lines or tubes to communicate fluid between the two injector portions 420 and 422. Both fuel and high pressurized actuating fluid are supplied directly to the engine head 418. This configuration substantially reduces the opportunity for leaking connections within the fuel injection system 410.

Claims

A hydraulically-actuated electronically-controlled fuel injection system (10,130,310,410) comprising:
an electronic control module (12,132,312,412);
an actuator portion (22,142,320,420) in fluid communication with a source of high pressure actuating fluid (18,138,313,414) and having a solenoid (50,172,172,456) electrically connected with the electronic control module responsive to electrical signals therefrom and also having a poppet valve (58,184,184,458) operably displaced by the solenoid between a first poppet valve position blocking high pressure actuating fluid and a second poppet valve position communicating high pressure actuating fluid therepast;
an intensification portion (22,146,324,422) having a cylinder (77,210,210,210) with a piston (78,212,212,212) slidably disposed therein defining in part a pressurization chamber (74,206,206,206) in fluid communication with the actuator portion and being pressurized thereby when the poppet valve is in the second position and having a plunger (82,216,216,216) defining in part a fuel pressurization chamber (86,220,220,220) and at least operably engaged by the piston wherein a working area of the piston is greater than a working area of the plunger, the plunger operably pressurizing fuel to a greater pressure than the pressure of the hydraulic actuating fluid; and
a nozzle portion (24,146,324,422) disposed in the engine head and having a nozzle tip (120,246,246,246) with a valve check (112,248,248,248) slidably disposed therein cooperatively defining an annular discharge chamber (118,254,254,254) in fluid communication with the fluid pressurization chamber, the valve check being biased to a first valve check position engaging a seat (122,258,258,258) of the tip by a spring (114,250,250,250) and being biased to a second valve check position spaced from the seat exposing an injection orifice (124,260,260,260) by pressurized fuel acting thereon when the poppet valve is in the second position, wherein at least one of the actuator portion and the intensification portion are axially offset from the nozzle portion.
A hydraulically-actuated electronically-controlled fuel injection system as claimed in claim 1, wherein:
the actuator portion (22) and the intensification portion (22) are combined in a single unit (22);
a manifold block (14) defines a fuel manifold (34) and a high pressure actuating fluid manifold (30) and receives a plurality of unitized actuator (22) and intensification portions (22) therein, and spaced from the engine head; and
a high pressure fuel line (25) disposed between the intensification portion and the nozzle portion, communicating high pressure fuel therebetween.
A hydraulically-actuated electronically-controlled fuel injection system as claimed in claim 2, wherein the manifold includes an integral high pressure pump (16).
A hydraulically-actuated electronically-controlled fuel injection system as claimed in claim 1, wherein:
the nozzle portion (146) and the intensification portion (146) are formed as an integral unit (146), and disposed in the engine head;
the engine head has a fuel channel (150) disposed therein;
a manifold block (134) has channels (154) for the distribution of high pressure actuating fluid and receives a plurality of actuator portions (142); and
a high pressure actuating fluid line (144) is disposed between the actuator portion (142) and the intensification portion (146).
A hydraulically-actuated electronically-controlled fuel injection system as claimed in claim 1, wherein:
the engine block defines a fuel manifold (328);
the nozzle portion (324) and the intensification portion (324) are combined into a single unit (324), a plurality of which are disposed in the engine head;
a plurality of mini blocks (316) have disposed in each a single actuator portion (320), the actuator portion connected to the intensification portion by a high pressure actuating fluid line (322) communicating fluid therebetween;
a high pressure actuating fluid manifold (314) receiving highly pressurized actuating fluid from the source of high pressure actuating fluid (313) and having a plurality of outlets; and
a plurality of high pressure actuating fluid lines (318) with one disposed between each of the outlets and a corresponding one of the mini blocks and communicating high pressure actuating fluid therebetween.
A hydraulically-actuated electronically-controlled fuel injection system as claimed in claim 1, wherein:
the engine head (418) defines an actuating fluid manifold (436) connected to the source of high pressure actuating fluid and a low pressure fuel manifold (428);
the intensification portion (422) and the nozzle portion (422) are integrated into a single unit (422), and disposed in the head in the fluid communication with the low pressure fuel manifold;
the actuating portion (420) is disposed in the head and is in fluid communication with the high pressure actuating fluid manifold; and
the engine head additionally defines secondary high pressure oil passages (452) providing fluid communication between the actuating portion and the intensification portion.