JP2008045408A - Fuel injection device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a fuel injection device applicable even to an engine of a different machine model, by having interchangeability in a supply pump. <P>SOLUTION: This fuel injection device of the engine has the supply pump 3 for pressurizing and forcibly feeding fuel to a pressure accumulating chamber 2 by sucking the fuel forcibly fed from a feed pump 9 by a pressurizing chamber 8, by reciprocating a plunger 33 by rotation of a camshaft 40 interlocked with and connected to a crankshaft of the engine. The supply pump 3 is installed on an engine body 30 as a separate body, and the feed pump 9 is installed on the opposite side of the engine body 30 of the supply pump 3. The supply pump 3 and the feed pump 9 are integrally constituted, and both pumps 3 and 16 are driven by the rotation of the camshaft 40. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine fuel injection apparatus including a supply pump that reciprocates a plunger by rotation of a camshaft linked to an engine crankshaft to suck and pump fuel in a pressurizing chamber.

2. Description of the Related Art Conventionally, an engine fuel injection device comprising a plurality of injectors, a pressure accumulation chamber that stores high-pressure fuel and that can be supplied to each injector, and a supply pump that pressurizes the fuel and pumps it to the pressure accumulation chamber is known. It has become. In such a fuel injection device, the supply pump is configured to reciprocate the plunger by the rotation of the camshaft to suck and pump fuel in the pressurizing chamber (see, for example, Patent Document 1). ). An intake amount control valve is provided in a fuel passage communicating with the fuel tank via the feed pump, and the intake amount control valve controls the fuel pressure-fed from the feed pump to the pressurization chamber of the supply pump. It was.
Japanese Patent Laid-Open No. 7-332186

  However, in the conventional fuel injection device, since the supply pump is integrated with the engine body, there is a case where the supply pump is not compatible and the supply pump cannot be attached to different types of engines. Further, the supply pump may be configured to be provided separately from the feed pump in the engine body and connected by piping. In this case, the number of assembling steps increases, and sufficient assemblability cannot be obtained. In addition, there are problems that fuel cannot be sucked into the supply pump due to broken pipes or poor connection, and that the fuel injection device cannot be miniaturized because pipes and suction control valves are provided outside the supply pump. .

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, in claim 1, the plunger is reciprocated by the rotation of the camshaft linked to the crankshaft of the engine, the fuel pumped in from the feed pump is sucked in the pressurizing chamber, and the fuel is pressurized. In a fuel injection device for an engine having a supply pump for pumping to a pressure accumulating chamber, the supply pump is attached as a separate body to the engine body, a feed pump is attached to the opposite side of the supply pump to the engine body, and the supply pump And the feed pump are integrally configured, and both pumps are driven by the rotation of the cam shaft.

  According to a second aspect of the present invention, the supply pump has a built-in intake amount control valve for adjusting the intake amount of the fuel pumped from the feed pump into the pressurizing chamber.

  According to a third aspect of the present invention, a fuel passage for pumping fuel from the feed pump to the pressurizing chamber is built in the supply pump, and the intake amount control valve is disposed in the fuel passage.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect, the supply pump and the feed pump can be handled as one unit, the assembly man-hour can be reduced, and the assemblability of the fuel injection device can be improved. In addition, the supply pump can be applied to different types of engines with compatibility.

  According to the second aspect of the present invention, the fuel injection device can be downsized as compared with the case where the intake amount control valve is attached to the outside of the supply pump.

  In Claim 3, the piping which connects the said supply pump and a feed pump becomes unnecessary, a fuel-injection apparatus can be reduced in size, and the assembly property can be improved. Furthermore, since the trouble that the fuel cannot be sucked into the supply pump due to damage to the piping or poor connection can be eliminated, the reliability of the fuel injection device can be improved.

  Next, embodiments of the invention will be described.

  1 is a diagram showing an overall configuration of a fuel injection device according to an embodiment of the present invention, FIG. 2 is a front sectional view of a supply pump, FIG. 3 is a sectional view taken along arrow AA in FIG. 2, and FIG. FIG. 5 is a sectional view taken along the line CC in FIG. 2, FIG. 6 is a sectional view taken along the line DD in FIG. 2, and FIG. 7 is a sectional view taken along the line EE in FIG. It is.

  First, an engine fuel injection device according to an embodiment of the present invention will be described.

  As shown in FIG. 1, the fuel injection device includes a plurality of injectors 1, 1, 1, a pressure accumulation chamber 2 that stores high-pressure fuel and can supply the fuel to each injector 1, 1, 1, 1, A supply pump 3 that pressurizes the fuel and pumps it to the pressure accumulating chamber 2, a feed pump 9 that pumps the fuel from the fuel tank 10 to the supply pump 3, and the like. The supply pump 3 includes a plunger 33, and reciprocates the plunger 33 via the tappet 36 by the rotation of the cam 41 driven in conjunction with the crankshaft via a gear or the like, thereby supplying fuel to the pressurizing chamber 8. The fuel that has been sucked in and pressurized and increased in pressure can be pumped to the pressure accumulating chamber 2.

  A suction side fuel passage 11 is formed between the pressurizing chamber 8 of the supply pump 3 and the fuel tank 10, and a feed pump 9, a suction amount control valve 12, and a check valve 13 are provided in the suction side fuel passage 11. Is arranged so that the fuel pumped up from the fuel tank 10 by the feed pump 9 can be sucked into the pressurizing chamber 8 through the suction amount control valve 12 and the check valve 13. The pressurizing chamber 8 and the pressure accumulating chamber 2 are connected by a discharge-side fuel passage 15, and the fuel whose pressure is increased through the discharge-side fuel passage 15 passes a check valve 16 from the pressurizing chamber 8 to the pressure accumulating chamber 2. Can be pumped through.

  A bypass passage 18 is provided between the discharge side and the suction side of the feed pump 9 in the suction side fuel passage 11, and a pressure regulating valve 19 is disposed in the bypass passage 18. The pressure of the fuel sucked into the pressurizing chamber 8 can be adjusted. The intake side fuel passage 11 is provided with a temperature sensor 20 so that the temperature of the fuel can be measured by the temperature sensor 20.

  A suction amount control valve 12 is provided on the discharge side of the feed pump 9 in the suction side fuel passage 11, and the amount of fuel sucked into the pressurizing chamber 8 of the supply pump 3 is adjusted by the suction amount control valve 12. Be able to. A check valve 13 is provided between the suction amount control valve 12 of the suction side fuel passage 11 and the pressurization chamber 8, and is pumped by the feed pump 9 to the pressurization chamber 8 by the suction side check valve 13. This prevents the back flow of fuel.

  A check valve 16 is provided between the pressurizing chamber 8 and the pressure accumulating chamber 2 of the discharge side fuel passage 15, and is supplied to the pressure accumulating chamber 2 by the supply pump 3 by the discharge side check valve 16. Backflow of fuel pressurized in the pressure chamber 8 is prevented. A plurality of injectors 1, 1, 1, 1 are connected to the pressure accumulating chamber 2, and high pressure fuel is supplied from the pressure accumulating chamber 2 to each injector 1, and fuel injection is performed in each injector 1. It has become.

  The pressure accumulating chamber 2 is provided with a pressure control valve 22 for controlling the fuel pressure in the accumulating chamber 2. By opening this, the fuel is released from the pressure accumulating chamber 2 to the fuel tank 10 through the fuel escape passage 23. The fuel pressure in the pressure accumulating chamber 2 is controlled to the set pressure. The pressure accumulation chamber 2 is further provided with a pressure sensor 24 for detecting the fuel pressure in the pressure accumulation chamber 2, and is connected to the controller 25 together with the pressure control valve 22. Then, the controller 25 controls the opening / closing of the pressure control valve 22 based on the detected value of the fuel pressure by the pressure sensor 24, and adjusts the fuel escape amount, thereby maintaining the fuel pressure in the pressure accumulating chamber 2 at the set pressure. Is configured to do.

  In this embodiment, as described above, the fuel pressure in the pressure accumulating chamber 2 is controlled by adjusting the amount of fuel released from the pressure control valve 22, and the suction amount control valve 12 is controlled by the released fuel. Thus, the amount of fuel sucked into the pressurizing chamber 8 of the supply pump 3 can be adjusted. Note that the suction amount control valve may be an electromagnetic valve, and may be controlled by the controller 25 instead of the pressure control valve 22 as in this embodiment.

  Specifically, as shown in FIG. 7, the intake amount control valve 12 introduces the fuel released from the pressure accumulating chamber 2 by the pressure control valve 22 into the control chamber 12a through the fuel escape passage 23, and the fuel. Then, the piston 28 is moved in a direction to partially close or completely close the fuel outlet 12c against the spring force of the spring 27, and flows into the supply chamber 12b from the fuel inlet 12d. The amount of the discharged fuel that flows out from the fuel outlet 12c can be adjusted. That is, the flow rate of the fuel flowing through the intake amount control valve 12 can be adjusted. By controlling the pressure control valve 22 in this way, the intake amount control valve 12 can be controlled so that the amount of fuel sucked into the pressurizing chamber 8 can be adjusted, whereby the fuel pressure in the pressure accumulating chamber 2 can be controlled. It is like that.

  Next, a specific configuration of the supply pump 3 provided in the fuel injection device will be described.

  As shown in FIGS. 2 and 3, the supply pump 3 is configured as a separate body from the engine body 30 and is detachably attached to the engine body 30. In the supply pump 3, plunger barrels 32 and 32 are inserted into the upper portion of the supply pump main body 31, and a plunger 33 is provided in each plunger barrel 32 so as to reciprocate in the vertical direction. A spring receiver 34 is disposed below each plunger barrel 32, and a lower end portion of a plunger 33 protruding from the plunger barrel 32 is engaged with the spring receiver 34. A spring 35 is interposed between the lower end portion of the plunger barrel 32 and the spring receiver 34 so as to expand and contract in the axial direction of the plunger 33, and the plunger 33 is urged downward by the urging force of the spring 35. ing.

  Below the plunger barrel 32, a tappet 36 is disposed on the same axis as the plunger 33, and is provided in the supply pump main body 31 so as to reciprocate up and down below the plunger 33. The tappet 36 includes a cylindrical tappet guide 36a and a tappet roller 36b, and is configured to rotatably support the tappet roller 36b so that a part of the tappet roller 36b protrudes downward in the lower portion of the tappet guide 36a. The spring receiver 34 is fitted on the upper portion of the tappet guide 36a, and the tappet 36 is urged downward by the urging force of the spring 35 together with the plunger 33, and the camshaft disposed below the tappet roller 36b. It is possible to press contact with a cam 41 on 40.

  The cam shaft 40 is disposed below the supply pump main body 31 in a direction orthogonal to the axial direction of the plunger 33 and is rotatably supported. One end of the camshaft 40 is inserted into the engine body 30, and a crankshaft provided in the engine body 30 via another power transmission mechanism such as a drive gear fixed thereto and a gear meshing with the drive gear Linked together. As a result, power is transmitted from the crankshaft to the camshaft 40 so that the camshaft 40 can rotate. When the cams 41 are arranged in parallel with appropriate phase differences at positions facing the respective tappets 36 of the camshaft 40 and power is transmitted from the crankshaft to the camshaft 40, the camshaft 40 rotates together with the camshaft 40. Is configured to do.

  In addition, the suction side check valve 13, the discharge side check valve 16, and the joint 43 are provided in this order from the plunger 33 side to the upper part in the plunger barrel 32. The suction-side check valve 13, the discharge-side check valve 16, and the joint 43 are disposed above the plunger 33 on the same axis as the plunger 33 and between the plunger 33 and the suction-side check valve 13. Fuel pressure-fed from the feed pump 9 through the suction side fuel passage 11 to the formed pressurization chamber 8 is sucked through the suction side check valve 13 and pressurized by the plunger 33 in the pressurization chamber 8. The fuel can be pumped from the joint 43 to the pressure accumulating chamber 2 through the discharge side fuel passage 15 via the discharge side check valve 16.

  Thus, as each cam 41 rotates in accordance with the rotation of the cam shaft 40, each plunger 33 reciprocates in the plunger barrel 32 as appropriate in the vertical direction. The suction and the pumping of fuel from the pressurizing chamber 8 are alternately performed. That is, the plunger 33 is energized by the energizing force of the spring 35 and starts to move downward from the uppermost position, so that a fuel intake stroke is started, and is pumped from the fuel tank 10 through the intake side fuel passage 11 by the feed pump 9. The fuel is sucked into the pressurizing chamber 8 through the suction side check valve 13. On the other hand, when the plunger 33 is pushed up by the cam 41, it starts to move upward from the lowest position against the biasing force of the spring 35, so that the pressure feeding stroke is started, and the fuel in the pressurizing chamber 8 is discharged to the discharge side check valve 16. The pressure is fed from the joint 43 to the pressure accumulating chamber 2 via the.

  In the supply pump 3, a feed pump 9 is detachably attached to the opposite side of the engine body 30. The feed pump 9 is configured as one unit with the supply pump 3 by fixing one side of the feed pump main body 45 in contact with the side opposite to the engine main body 30 of the supply pump main body 31. A pump drive shaft 46 is disposed on the feed pump main body 45 on the same axis as the cam shaft 40 of the supply pump main body 31 and is rotatably supported. One end of the pump drive shaft 46 is linked to the cam shaft 40 via a coupling or the like, so that the pump drive shaft 46 and the cam shaft 40 can rotate together. Thus, the feed pump 9 is driven by the rotation of the pump drive shaft 46 accompanying the rotation of the camshaft 40, so that fuel can be pumped from the fuel tank 10 and pumped to the supply pump 3 through the suction side fuel passage 11. Yes. In addition, although the trochoid pump, a gear pump, a vane pump, etc. are used for the feed pump of a present Example, it is not limited.

  Subsequently, a fuel passage for pumping fuel from the fuel tank 10 to the pressure accumulating chamber 2 using a supply pump and a feed pump will be described.

  The suction-side fuel passage 11 that connects the supply pump 3 and the fuel tank 10 has a plurality of communication lines formed in the piping 48 that connects the fuel tank 10 and the feed pump 9, the supply pump main body 31, and the feed pump main body 45. It is comprised with the holes 11a-11k. In the supply pump main body 31 and the feed pump main body 45, for example, as shown in FIGS. 2 to 7, one end of a pipe 48 extending from the fuel tank 10 is connected to a joint 49 provided in the supply pump main body 31. The pipe 48 communicates with a first series of through holes 11a (FIG. 4) formed in the upper part of the supply pump main body 31 on the feed pump main body 45 side. The first communication hole 11a extends downward from the joint 49 and communicates with a second communication hole 11b (FIG. 5) formed on the side of the supply pump main body 31 of the feed pump main body 45.

  The second communication hole 11b is provided with the bypass passage 18 and the pressure regulating valve 19 in the middle of the second communication hole 11b. The second communication hole 11b extends downward from the communication part with the first communication hole 11a and is formed in the feed pump main body 45. The feed pump 9 is connected to the suction port 45a. And the 3rd communicating hole 11c formed in the supply pump main body 31 side part of the feed pump main body 45 is connected by the discharge port 45b of the feed pump 9. FIG. The third communication hole 11c extends upward from the communication portion with the discharge port 45b substantially parallel to the second communication hole 11b and communicates with a fourth communication hole 11d formed in the upper portion of the feed pump main body 45. The fourth communication hole 11d extends laterally from the communication portion with the third communication hole 11c and communicates with a fifth communication hole 11e formed in the feed pump main body 45.

  The fifth communication hole extends from the communication part with the fourth communication hole 11d to the supply pump main body 31 side, and a sixth communication hole 11f (FIG. 2) formed on the side of the feed pump main body 45 of the supply pump main body 31. ). The sixth communication hole 11f has a larger diameter than the fifth communication hole 11e, extends from the communication part to the engine body 30 side, and communicates with a seventh communication hole 11g formed in the upper part of the supply pump body 31. . The seventh communication hole 11g includes the suction amount control valve 12 built in the supply pump main body 31 in the middle thereof, and extends from the communication portion with the sixth communication hole 11f to the one plunger barrel 32 side. And the eighth communication hole 11h formed by the supply pump main body 31.

  The eighth communication hole 11h is annularly provided around the plunger barrel 32, and is connected to the pressurizing chamber 8 above the plunger 33 through the communication hole 32a formed in the plunger barrel 32 and the suction side check valve 13. While communicating, it communicates with a ninth communication hole 11j formed between both plunger barrels 32, 32 of the supply pump main body 31. The ninth communication hole 11j extends from the communication portion with the eighth communication hole 11h to the other plunger barrel 32 side and communicates with a tenth communication hole 11k formed by the plunger barrel 32 and the supply pump body 31. . Similarly to the eighth communication hole 11h, the tenth communication hole is provided in an annular shape around the other plunger barrel 32, and the communication hole 32a formed in the plunger barrel 32 and the suction-side reverse support valve 13 are provided. The pressure chamber 8 is communicated with the pressure chamber 8 above the plunger 33.

  Thus, the suction side fuel passage 11 is constituted by the first to tenth communication holes 11 a to 11 k in the supply pump main body 31 and the feed pump main body 45. In the intake side fuel passage 11, fuel is pumped from the fuel tank 10 by the feed pump 9 through the pipe 48, the first communication hole 11 a of the supply pump main body 31 and the second communication hole 11 b of the feed pump main body 45. Through the third communication hole 11c, the fourth communication hole 11d, the fifth communication hole 11e of the main body 45, and the sixth communication hole 11f of the supply pump main body 31, the suction flow control valve 12 of the seventh communication hole 11g is reached. After the flow rate is adjusted by the valve 12, the pressure is fed from the eighth communication hole 11h to the pressurizing chamber 8 on the one plunger barrel 32 side via the suction side check valve 13, and at the same time, the eighth communication hole 11h and the ninth The pressure is fed from the tenth communication hole 11k to the pressure chamber 8 on the other plunger barrel 32 side through the suction hole check valve 13 through the communication hole 11j.

  On the other hand, the discharge side fuel passage 15 communicating the supply pump 3 and the pressure accumulating chamber 2 is constituted by a pipe 51 (FIG. 5) connecting the supply pump 3 and the pressure accumulating chamber 2. That is, one end of a pipe 51 extending from the pressure accumulating chamber 2 is connected to the joint 43 provided in each plunger barrel 32 in the supply pump main body 31, and the pipe 51 connects the joint 43 and the discharge side check valve 16. The pressure chamber 8 is configured to be communicated with the pressurizing chamber 8. As a result, in the discharge side fuel passage 15, the fuel pressurized by the plunger 33 in the pressurizing chamber 8 reaches the joint 43 through the discharge side check valve 16 and is pumped from the joint 43 to the pressure accumulating chamber 2 through the pipe 51. It has become so. Thus, the fuel passage is constituted by the suction side fuel passage 11 and the discharge side fuel passage 15, and the fuel in the fuel tank 10 is pressurized by the supply pump 3 through the fuel passage and can be pumped to the pressure accumulating chamber 2.

  As described above, the plunger 33 is reciprocated by the rotation of the camshaft 40 linked to the engine crankshaft, the fuel pumped in from the feed pump 9 is sucked in the pressurizing chamber 8, and the fuel is pressurized. In the fuel injection device for an engine provided with a supply pump 3 that is pumped to the pressure accumulating chamber 2, the supply pump 3 is attached as a separate body to the engine body 30, and a feed pump is provided on the opposite side of the supply pump 3 from the engine body 30. 9, the supply pump 3 and the feed pump 9 are integrally configured, and both the pumps 3 and 9 are driven by the rotation of the cam shaft 40, whereby the supply pump 3 and the feed pump 9 Can be handled as a single unit, reducing the number of assembly steps and improving the assembly of the fuel injection device. Kill. In addition, the supply pump 3 can be applied to different types of engines with compatibility.

  Further, in the fuel injection device of the engine, the supply pump 3 has a built-in intake amount control valve 12 that adjusts the intake amount of the fuel pumped from the feed pump 9 into the pressurizing chamber 8. The fuel injection device can be reduced in size as compared with the case where the quantity control valve 12 is attached to the outside of the supply pump 3.

  In the fuel injection device of the engine, a fuel passage for pumping fuel from the feed pump 9 to the pressurizing chamber 8 to the supply pump 3, that is, a suction side fuel passage 11 including a plurality of communication holes 11a to 11k. Since the intake amount control valve 12 is disposed in the fuel passage 11, a pipe for connecting the supply pump 3 and the feed pump 9 becomes unnecessary, and the fuel injection device can be downsized. Moreover, the assemblability can be improved. Furthermore, since the problem that the fuel cannot be sucked into the supply pump 3 due to damage to the piping or poor connection can be eliminated, the reliability of the fuel injection device can be improved.

The figure which shows the whole structure of the fuel-injection apparatus which concerns on one Example of this invention. Front sectional drawing of a supply pump. AA arrow sectional drawing in FIG. BB arrow sectional drawing in FIG. CC sectional view taken on the line in FIG. The DD arrow directional cross-sectional view in FIG. EE arrow sectional drawing in FIG.

Explanation of symbols

2 Pressure accumulating chamber 3 Supply pump 8 Pressurizing chamber 9 Feed pump 11 Fuel passage 12 Suction amount control valve 15 Fuel passage 30 Engine body 33 Plunger 40 Camshaft

Claims (3)

A supply pump that reciprocates the plunger by the rotation of the camshaft linked to the crankshaft of the engine, sucks the fuel pumped from the feed pump in the pressurizing chamber, pressurizes the fuel, and pumps it to the accumulator chamber In the engine fuel injection device provided,
The supply pump is mounted separately from the engine body, a feed pump is mounted on the opposite side of the supply pump from the engine body, and the supply pump and the feed pump are integrally formed. An engine fuel injection device characterized in that both pumps are driven.   2. The fuel injection device for an engine according to claim 1, wherein an intake amount control valve for adjusting an intake amount of fuel pumped from the feed pump into the pressurizing chamber is incorporated in the supply pump. 3. The engine according to claim 2, wherein the supply pump has a built-in fuel passage for pumping fuel from the feed pump to the pressurizing chamber, and the intake amount control valve is disposed in the fuel passage. Fuel injectors.

Images