JP2015068295A - Fuel injection pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection pump capable of improving generation of Sd and deterioration of a white smoke extinction time.SOLUTION: A fuel injection pump 100 feeds fuel to be injected in a combustion chamber of a diesel engine at high pressure, and is provided with a delivery valve 113 at the middle of a path for pressure-feeding the fuel to a fuel injection nozzle from a plunger 104. The pump comprises a capacity increasing/decreasing mechanism 10 that is communicated with a delivery chamber R for housing the delivery valve 113, and whose capacity decreases as the engine rotation number increases, and increases as the engine rotation number decreases.

Description

  The present invention relates to a technology of a fuel injection pump.

  BACKGROUND ART A fuel injection pump is known as a pump that delivers fuel injected into a combustion chamber of a diesel engine at a high pressure. The fuel injection pump is configured to send fuel that is pumped by sliding the plunger up and down in the plunger barrel to a plurality of discharge valves and to pump the fuel from each discharge valve to a fuel injection nozzle (for example, Patent Document 1).

  In a diesel engine, it is necessary to significantly reduce “soot (hereinafter referred to as Sd)” by regulation. In a diesel engine, in order to significantly reduce Sd, it is effective to retard the fuel injection timing.

  On the other hand, in a diesel engine, if the fuel injection timing is retarded, the white smoke disappearance time (the time from when the engine starts until the white smoke disappears) is greatly deteriorated. The tendency of the white smoke extinguishing time to deteriorate is a phenomenon that is noticeable when starting at high idle (low load and high rotation).

  That is, the generation of Sd and the deterioration of the white smoke disappearance time are in a trade-off relationship. It has been found that if the fuel injection timing is retarded over the entire engine speed range and then the fuel injection timing is advanced only at high speed, the generation of Sd and the deterioration of the white smoke extinction time can be improved. Yes.

JP 11-44274 A

  The problem to be solved by the present invention is to provide a fuel injection pump capable of improving the generation of Sd and the deterioration of the white smoke extinguishing time.

  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 the first aspect of the present invention, the fuel injection pump is provided with a delivery valve provided in the middle of a path in which fuel injected into the combustion chamber of the diesel engine is sent out at a high pressure and fuel is pumped from the plunger to the fuel injection nozzle. Is provided with a volume increasing / decreasing mechanism that communicates with the delivery chamber in which the volume is reduced and that the volume decreases as the engine speed increases and the volume increases as the engine speed decreases.

  According to a second aspect of the present invention, in the fuel injection pump according to the first aspect, the engine speed is detected by an engine speed sensor, and the volume of the volume increasing / decreasing mechanism is increased / decreased by a solenoid actuator.

  According to a third aspect of the present invention, in the fuel injection pump according to the first aspect, the volume of the volume increasing / decreasing mechanism is increased or decreased by a hydraulic pump driven by a camshaft.

  According to a fourth aspect of the present invention, in the fuel injection pump according to the first aspect, the volume of the volume increasing / decreasing mechanism is increased or decreased by the rotation of the regulator lever.

  According to the fuel injection pump of the present invention, the generation of Sd and the deterioration of the white smoke extinguishing time can be improved.

The side view which showed the structure of the fuel injection pump. The side view which showed the structure of the delivery chamber. FIG. 3 is a schematic diagram illustrating a configuration of a volume increasing / decreasing mechanism according to the first embodiment. FIG. 5 is a schematic diagram illustrating a configuration of a volume increasing / decreasing mechanism according to a second embodiment. FIG. 6 is a schematic diagram illustrating a configuration of a volume increasing / decreasing mechanism according to a third embodiment.

The configuration of the fuel injection pump 100 will be described with reference to FIG.
In FIG. 1, the fuel injection pump 100 is partially shown in a sectional view and a side view.

  The fuel injection pump 100 is an embodiment according to the fuel injection pump of the present invention. The fuel injection pump 100 is provided in a diesel engine. The fuel injection pump 100 sends out fuel injected into a combustion chamber of a diesel engine at a high pressure.

  The fuel injection pump 100 has a cylindrical plunger barrel 103 inserted in a hole drilled downward from the upper surface of the pump housing 102. A plunger 104 is inserted into the plunger barrel 103 so as to be slidable up and down. A pressurizing chamber 107 is formed above the plunger 104.

  Below the plunger 104, a tappet 108 is inserted in the pump housing 102 so as to be slidable up and down integrally with the plunger 104. A cam 109 is in contact with the lower surface of the tappet 108. Plunger 104 and tappet 108 are urged downward by plunger spring 105.

  The cam 109 is provided on the cam shaft 110. The cam shaft 110 is pivotally supported by the pump housing 102 of the fuel injection pump 100 via a cam bearing 111. A delivery valve 113 is provided above the plunger 104. Details of the delivery valve 113 will be described later.

  With such a configuration, as the cam shaft 110 rotates, the tappet 108 and the plunger 104 slidably contacted with the outer periphery of the cam 109 slide up and down and the fuel is pumped by a fuel feed pump (not shown). When the plunger 104 slides upstream (downward), the pressure-fed fuel opens the barrel port 106 and is sucked into the pressurizing chamber 107. The fuel sucked into the pressurizing chamber 107 is pressurized when the plunger 104 slides downstream (upward).

The configuration of the delivery valve 113 will be described with reference to FIG.
In FIG. 2, the delivery valve 113 is shown in a partial cross-sectional view and a side view.

  The delivery valve 113 includes a tubular delivery valve case 114, a delivery valve body 116, and a delivery valve spring 115 that urges the delivery valve body 116 toward the delivery valve case 114 side.

  The delivery valve case 114 and the plunger barrel 103 are inserted into a hole drilled downward from the upper surface of the pump housing 102 (see FIG. 1). The delivery valve body 116 is inserted below the spring housing portion 112 d of the casing 112 so as to be slidable up and down, and is urged toward the delivery valve case 114 (downward) by the delivery valve spring 115. Here, a space formed by the receiving body 120, the spring housing portion 112 d, and the delivery valve body 116 is referred to as a delivery chamber R.

  The casing 112 is a cylindrical member, and is inserted into a hole drilled from the upper surface of the pump housing 102 from above. A through hole is formed in the axial center portion of the casing 112, and the inside thereof has a fuel discharge port 112a, a small-diameter fuel passage 112b, a guide body storage portion 112c, a spring storage portion 112d, and a delivery valve case fitting portion from above. 112e is formed.

  The fuel discharge port 112a is formed in a tapered shape extending in the downstream direction at the downstream end portion of the through hole, and is connected to a high pressure pipe. A small-diameter fuel passage 112b is formed in the lower part (upstream side) of the fuel discharge port 112a to receive one side of the damping valve spring 118. A guide body housing portion 112c is formed on the upstream side of the small-diameter fuel passage 112b, and houses the guide body 122, the valve body 121, and the receiving body 120.

  A spring storage portion 112d is formed on the upstream side of the guide body storage portion 112c, and stores the delivery valve spring 115 and the upper portion of the delivery valve body 116. A delivery valve case fitting portion 112e for fitting the upper portion of the delivery valve case 114 is formed below the spring housing portion 112d.

  A damping valve 117 is provided above (on the downstream side) the delivery valve 113. The damping valve 117 is configured such that the valve body 121 is urged downward by a damping valve spring 118 so that the valve body 121 contacts the receiving body 120.

  With such a configuration, when the pressurized fuel pressure in the pressurizing chamber 107 exceeds the predetermined valve opening pressures of the delivery valve 113 and the damping valve 117, the delivery valve body 116 and the valve body 121 are located on the downstream side. (Upward), the delivery valve 113 and the damping valve 117 are opened, and fuel is supplied to a fuel injection nozzle (not shown) via the spring housing portion 112d, the passage hole 120a, the small-diameter fuel passage 112b, and the fuel discharge port 112a. It will be pumped.

The configuration of the volume addition mechanism 10 according to the first embodiment will be described with reference to FIG.
In FIG. 3, the volume adding mechanism 10 is shown in partial cross-sectional view and side view.

  The volume adding mechanism 10 communicates with the delivery chamber R, and decreases in volume as the engine speed increases, and increases in volume as the engine speed decreases. The volume addition mechanism 10 includes a passage 11, a cylinder chamber 12, a fuel chamber 12 a, a piston 13, a solenoid 14, and a controller 50.

  The cylinder chamber 12 constitutes a fuel chamber 12 a with a piston 13. The passage 11 communicates between the delivery chamber R formed in the casing 112 and the fuel chamber 12a. The piston 13 slides inside the cylinder chamber 12 to increase or decrease the volume of the fuel chamber 12a. The solenoid 14 is connected to the controller 50 and drives the piston 13 to reciprocate.

  The controller 50 is connected to the solenoid 14 and an engine speed sensor 51 that detects the engine speed of an engine (not shown) provided with the fuel injection pump 100. The controller 50 drives the piston 13 by the solenoid 14 so that the volume of the cylinder chamber 12 decreases as the engine speed increases, and the solenoid 14 causes the volume of the cylinder chamber 12 to increase as the engine speed decreases. It has a function of driving the piston 13.

The operation of the volume addition mechanism 10 will be described.
In the volume addition mechanism 10, the volume of the cylinder chamber 12 of the volume addition mechanism 10 is added to the volume of the conventional delivery chamber R. For this reason, a time delay occurs until the injection pressure is propagated to a fuel injection nozzle (not shown), and the fuel injection timing is retarded. That is, by providing the volume addition mechanism 10, the fuel injection timing is retarded over the entire engine speed (first control).

  On the other hand, in the volume addition mechanism 10, the volume of the cylinder chamber 12 decreases as the engine speed increases. Therefore, although the fuel injection timing is retarded throughout the engine speed by the first control, the time delay is improved until the injection pressure is propagated to the fuel injection nozzle (not shown), and the fuel injection timing is advanced. become. That is, only when the engine speed is high, the lead angle is advanced as compared to the first control (second control).

The effect of the volume addition mechanism 10 will be described.
According to the volume addition mechanism 10, the generation of Sd and the deterioration of the white smoke extinguishing time can be improved. That is, in the entire engine speed range, the fuel injection timing is retarded by the first control, and the fuel injection timing is advanced only at the high speed by the second control. Can be improved.

The structure of the volume addition mechanism 20 of Embodiment 2 is demonstrated using FIG.
In FIG. 4, the volume adding mechanism 20 is shown in a partial sectional view and a side view.

  The volume addition mechanism 20 communicates with the delivery chamber R, and decreases in volume as the engine speed increases, and increases in volume as the engine speed decreases. The volume addition mechanism 20 includes a passage 21, a cylinder chamber 22, a piston 23, a relief valve 24, and a hydraulic pump 25.

  Since the passage 21, the cylinder chamber 22, the fuel chamber 22a, and the piston 23 have the same configuration as the passage 11, the cylinder chamber 12, and the piston 13 of the first embodiment, the description thereof is omitted.

  The cylinder chamber 22 is divided into a fuel chamber 22 a and a hydraulic oil chamber 22 b by a piston 23. The switching valve 24 is provided on the way between the hydraulic pump 25 and the cylinder chamber 22. The switching valve 24 has a function of supplying the hydraulic oil to the hydraulic oil chamber 22 b of the cylinder chamber 22 when the hydraulic pressure of the hydraulic oil sent from the hydraulic pump 25 exceeds a predetermined pressure. The hydraulic pump 25 is driven by an engine provided with the fuel injection pump 100.

The operation of the volume addition mechanism 20 will be described.
In the volume addition mechanism 20, the volume of the cylinder chamber 22 of the volume addition mechanism 20 is added to the volume of the conventional delivery chamber R. For this reason, a time delay occurs until the injection pressure is propagated to a fuel injection nozzle (not shown), and the fuel injection timing is retarded. That is, by providing the volume addition mechanism 20, the fuel injection timing is retarded over the entire engine speed (first control).

  On the other hand, in the volume addition mechanism 10, when the operating pressure by the hydraulic pump 25 increases to a predetermined pressure or higher as the engine speed increases, the switching valve 24 is switched to supply the operating oil to the operating oil chamber 22b. Then, the piston 23 in the cylinder chamber 22 moves to the fuel chamber side 22a, and the volume of the combustion chamber 22a decreases. Therefore, although the fuel injection timing is retarded throughout the engine speed by the first control, the time delay is improved until the injection pressure is propagated to the fuel injection nozzle (not shown), and the fuel injection timing is advanced. become. That is, only when the engine speed is high, the lead angle is advanced as compared to the first control (second control).

The effect of the volume addition mechanism 20 will be described.
According to the volume addition mechanism 20, the generation of Sd and the deterioration of the white smoke extinction time can be improved. That is, in the entire engine speed range, the fuel injection timing is retarded by the first control, and the fuel injection timing is advanced only at the high speed by the second control. Can be improved.

The structure of the volume addition mechanism 30 of Embodiment 3 is demonstrated using FIG.
In FIG. 5, the volume adding mechanism 30 is shown in a partial sectional view and a side view.

  The volume addition mechanism 30 communicates with the delivery chamber R, and decreases in volume as the engine speed increases, and increases in volume as the engine speed decreases. The volume addition mechanism 30 includes a passage 31, a cylinder chamber 32, a piston 33, and a synchronization link 34.

  Since the passage 31, the cylinder chamber 32, the combustion chamber 32a, and the piston 33 have the same configuration as the passage 11, the cylinder chamber 12, the combustion chamber 12a, and the piston 13 of the first embodiment, description thereof is omitted.

  The regulator lever 52 is provided in an engine including the fuel injection pump 100. The regulator lever 52 is configured to adjust the fuel injection amount of the fuel injection pump 100 and to control the engine speed by being rotated.

  One end of the synchronization link 34 is rotatably supported on the other end side of the piston 33, and the other end is rotatably supported on one end side of the regulator lever 52. When the regulator lever 52 is rotated so as to control the engine speed to a high speed, the regulator lever 52 controls the engine speed to a low speed so that the volume of the cylinder chamber 32 is reduced. Thus, if it rotates, the piston 33 and the regulator lever 52 are supported so that the volume of the cylinder chamber 32 may increase.

The operation of the volume addition mechanism 30 will be described.
In the volume addition mechanism 30, the volume of the cylinder chamber 32 of the volume addition mechanism 30 is added to the volume of the conventional delivery chamber R. For this reason, a time delay occurs until the injection pressure is propagated to a fuel injection nozzle (not shown), and the fuel injection timing is retarded. That is, by providing the volume addition mechanism 20, the fuel injection timing is retarded over the entire engine speed (first control).

  On the other hand, in the volume addition mechanism 30, the volume of the cylinder chamber 32 decreases as the regulator lever 52 is rotated so that the engine speed increases. Therefore, although the fuel injection timing is retarded throughout the engine speed by the first control, the time delay is improved until the injection pressure is propagated to the fuel injection nozzle (not shown), and the fuel injection timing is advanced. become. That is, only when the engine speed is high, the lead angle is advanced as compared to the first control (second control).

The effect of the volume addition mechanism 30 will be described.
According to the volume addition mechanism 30, it is possible to improve the generation of Sd and the deterioration of the white smoke extinguishing time. That is, in the entire engine speed range, the fuel injection timing is retarded by the first control, and the fuel injection timing is advanced only at the high speed by the second control. Can be improved.

DESCRIPTION OF SYMBOLS 10 Volume addition mechanism 11 Communication path 12 Cylinder chamber 13 Piston 50 Controller 51 Engine speed sensor 100 Fuel injection pump 103 Plunger barrel 104 Plunger 112 Casing 113 Delivery valve R Delivery chamber

Claims (4)

A fuel injection pump in which a fuel to be injected into a combustion chamber of a diesel engine is sent out at a high pressure, and a delivery valve is provided in the middle of a path through which fuel is pumped from a plunger to a fuel injection nozzle,
A volume increasing / decreasing mechanism that communicates with the delivery chamber in which the delivery valve is housed, and that decreases in volume as the engine speed increases and increases in volume as the engine speed decreases;
Fuel injection pump. The fuel injection pump according to claim 1,
The engine speed is detected by the engine speed sensor,
The volume of the volume increasing / decreasing mechanism is increased or decreased by a solenoid actuator.
Fuel injection pump. The fuel injection pump according to claim 1,
The volume of the volume increasing / decreasing mechanism is increased or decreased by a hydraulic pump driven by a camshaft.
Fuel injection pump. The fuel injection pump according to claim 1,
The volume of the volume increasing / decreasing mechanism is increased or decreased by the rotation of the regulator lever.
Fuel injection pump.

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