JPS6143225A - Fuel injection pump of diesel engine - Google Patents

Abstract

PURPOSE:To improve startability of an engine when it is at a superlow temperature and suppress a black smoke of the engine when it is in warming operation, by providing in the peripheral surface of a plunger an auxiliary groove tilting along a slope in a head part upper end surface of the plunger. CONSTITUTION:A plunger 20 forms its head part upper end surface 28 in an end surface sloped in the axial direction, and the plunger 20 provides in its peripheral surface an auxiliary groove 32, tilting along a slope of said upper end surface 28, to be drilled. While a fuel injection pump provides an actuator 40 changing the moving distance of a control rack 22 in accordance with a temperature. When an engine is started at superlow temperature time, the pump, moving the control rack 22 to a maximum position, rotates a long groove 32A to a position where it is adapted to the bottom side wall of an introducing hole 12. The control rack is moved to the side of a short groove 32B in accordance with a temperature rise. In this way, the pump, improving startability of the engine when it is at a superlow temperature, enables a black smoke to be suppressed in the engine when it is in warming operation.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fuel injection pump for a diesel engine,
In particular, it relates to a series fuel injection pump mounted on a diesel engine.

[Conventional technology]

Conventionally, this type of in-line fuel injection pump has a plunger fitted into a plunger barrel so that it can move up and down and freely rotate.A cam rotated by the engine moves the plunger up and down to inject fuel, and at the same time, the plunger is rotated. There is a known system in which the amount of fuel injection is increased or decreased.

However, in the case of this fuel injection pump, the vertical movement of the plunger is performed by a cam rotated by the engine, so the fuel injection timing is always constant. For this reason, there was a problem in that starting performance during cold starting was reduced.

Therefore, Japanese Unexamined Patent Publication No. 57-129227, Utility Model Application No. 56
As described in Japanese Patent No. -67368, it has been proposed that in addition to the axially inclined groove formed in the plunger, a notched groove for regulating the fuel injection timing is formed.

[Problem that the invention seeks to solve]

However, with conventional pumps that have notched grooves to regulate fuel injection timing, the fuel injection amount is always controlled to be constant regardless of the temperature, which may reduce startability at extremely low temperatures. Therefore, when the fuel injection amount was controlled to increase, a problem occurred in that black smoke was emitted during warm-up. Furthermore, as the temperature drops, the viscosity of the lubricating oil increases and the engine/engine rotational speed decreases, so unless the injection timing is changed according to the temperature, startability will decrease.

The present invention was made in view of the above-mentioned conventional problem 1/C@, and its purpose is to improve starting performance at extremely low temperatures and to suppress the emission of black smoke during warm-up. It is an object of the present invention to provide a fuel injection pump for a diesel engine that can be used.

[Means for solving problems]

To achieve the above object, the present invention provides an axially inclined groove in a plunger barrel having a fuel introduction hole and forming a passage for supplying fuel from the fuel introduction hole to a fuel injection nozzle; A plunger having a hole that communicates with and extends to the upper end surface of the head is fitted so that it can move up and down and freely rotate, and the up and down movement of the plunger pressure-feeds and injects fuel, and changes the fuel injection amount and fuel injection depending on the rotational position of the plunger. In a diesel engine fuel injection pump that regulates timing, the effective stroke t-m of the control rack that rotates the plunger in conjunction with the accelerator pedal is maximum at low temperatures, and the effective stroke of the control rack decreases as the temperature increases. An actuator is provided to regulate the amount of movement of the control rack, and the upper end surface of the plunger head is formed into an end surface inclined in the axial direction, and the end surface is adjacent to the groove and inclined in the axial direction along the inclined surface of the upper end surface of the plunger head. An auxiliary groove is formed on the outer peripheral surface of the plunger on the head side of the groove, and the distance between the upper end surface of the plunger head and the auxiliary groove is
The timing of fuel injection at extremely low temperatures is later than that at high temperatures, and the fuel injection amount at extremely low temperatures is set to be greater than at high temperatures.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows the configuration of a preferred embodiment of the present invention. In FIG. 1, a fuel introduction hole 12 communicating with a fuel tank is bored in the side wall of a plunger barrel 10, and a delivery pulp 18 biased by a spring 16 is stored in a fuel chamber 14. Ru. That is, the plunger barrel 10 delivers fuel from the fuel introduction hole 12 to the pulp 1.
8 to form a passage for supplying fuel to the fuel injection nozzle.

Also, a plunger 20 is provided inside this plunger barrel 10.
is inserted so that it can move up and down and rotate freely.

The plunger 20 rotates via a control pinion 24 when a control rack 22 that is linked to an accelerator pedal moves in the direction of arrow X. Further, the plunger 20 is in contact with a camshaft (not shown) via a rod 26 and a tappet (not shown). As shown in FIG. 2, the plunger 20 has a head upper end surface 28 formed as an end surface inclined in the axial direction. A groove 30 inclined in the axial direction is formed in the surface, and an upper end surface 2 is provided adjacent to the groove 30.
An auxiliary groove 32 inclined in the axial direction is bored along the inclined surface 8. The groove 30 communicates with a vertical hole 34 bored in the upper end surface.

Here, the distance from the upper end surface 28 to the edge of the groove 32 is "1s".
a2 has a relationship of al>afi, and the dimension obtained by subtracting the diameter of the fuel introduction hole 12 is set as the effective stroke at idle link. Also, the upper end surface 2
8 to the side wall 34 b1. b is set as an advance angle amount.

When performing fuel injection using the plunger 20 configured in this way, first, as shown in FIG. Fuel is supplied into the fuel chamber 14 from the introduction hole 12 . Thereafter, as shown by the peak in FIG. The fluid pressure increases and delivery valve 1
8 begins to open against the biasing force of the spring 16, and fuel injection begins. After this, the plunger 20 further rises, (
C) As shown in the figure, when the groove 30 and the fuel introduction hole 12 communicate with each other, the hydraulic pressure in the fuel chamber 14 decreases and fuel injection is stopped. In this way, when the plunger 20 rises, the timing of fuel injection is regulated by the tie until the fuel introduction hole J2 is closed, and after the fuel introduction hole 12 is closed, the groove 30 is closed by the rise of the plunger 20. The amount of fuel to be injected is regulated by the time it takes to communicate with the fuel introduction hole 12.

Therefore, in this embodiment, the amount of movement of the control rack 22 is regulated in order to delay the fuel injection timing and increase the fuel injection amount at extremely low temperatures, and to advance the fuel injection timing and decrease the fuel injection amount at high temperatures. An actuator 40 is provided.

As shown in FIG. 1, the actuator 40 includes a control valve 42, a vacuum regulating valve 44, a negative pressure source 46, a temperature sensor 48, a filter 50, and the like. The control valve 42 has a diaphragm chamber 54 formed by a diaphragm 52 . Diaphragm chamber 5
A spring 56 is installed inside 4, and a diaphragm 52
is biased in the direction of arrow Y. Also, the diaphragm 52
A shaft-shaped stopper 58 that comes into contact with the end of the control rack 22 is fixed approximately at the center of the control rack 22 . In other words, the movement amount of the control rack 22 is regulated by the position of the stopper 58. The diaphragm 54 is connected to the vacuum regulating valve 44 via a tube 6o.

The vacuum regulating valve 44 is connected to the filter via a tube 62 , to the valve pressure source 46 via a tube 64 , and to the temperature sensor 48 via a signal line 66 . The temperature sensor 48 is configured to output a signal according to the engine cooling water temperature. Vacuum regulating valve 44 is configured to introduce negative pressure from negative pressure source 46° into diaphragm chamber 54 based on the output signal of temperature sensor 48 . The relationship between the negative pressure at which the negative pressure from the negative pressure source 46 is introduced into the diaphragm chamber 54 and the temperature is set as shown in FIG. That is, when the temperature is low, the negative pressure within the diaphragm chamber 54 is increased, and as the temperature increases, the negative pressure within the diaphragm chamber 54 is decreased. Therefore, at extremely low temperatures, the diaphragm 52 moves in the direction of the arrow 2, and the amount of movement of the control rack 22 is maximized. Further, since the diaphragm 52 moves in the direction of the arrow Y as the temperature increases, the amount of movement of the control rack 22 is regulated in a direction that reduces the effective stroke.

In the above configuration, when the accelerator is depressed at extremely low temperatures, the control rack 22 moves to the maximum effective stroke position. The plunger 20 rotates to a position where it abuts the side wall of the plunger 20. When the plunger 20 moves up and down in this position, the injection timing is delayed, the fuel injection amount is maximized, and starting performance can be improved. On the other hand, since the stopper 58 moves in the Y direction as the temperature rises, the portion of the groove 32 that communicates with the inner intake hole 12 moves toward the groove 32B side where the distance from the upper end surface 28 becomes shorter. Therefore, as the temperature rises, the fuel injection timing is gradually stopped earlier and the fuel injection amount is gradually reduced.

Therefore, it is possible to suppress the emission of black smoke during warm-up.

When the plunger 20 is not idle-linked, the plunger 20 is rotated to the position where the groove 300 communicates with the fuel introduction hole 12.
Fuel is controlled by the fuel injection timing and fuel injection amount depending on the position of the groove 30.

〔Effect of the invention〕

As explained above, according to the present invention, an actuator is provided that regulates the amount of movement of the control rack in such a direction that the effective stroke of the control rack is maximized at extremely low temperatures and is decreased as the temperature increases. At the same time, the upper end surface of the plunger head is formed into an end surface inclined in the axial direction, and further, an auxiliary groove is formed in the outer circumferential surface of the plunger that is inclined in the axial direction along the inclined surface of the upper end surface of the plunger head, The distance between the upper end surface of the plunger head and the auxiliary groove is set so that the fuel injection timing at cryogenic temperatures is later than at high temperatures, and the amount of solvent injection at cryogenic temperatures is smaller than at high temperatures. The excellent effects of improving startability and suppressing black smoke emission at room temperature can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the present invention, Fig. 2 is a block diagram of main parts of a plunger, and Figs. 3 (a) to (c) are diagrams for explaining the action of the fuel injection pump. , FIG. 4 is a diagram showing the relationship between temperature and negative pressure. 10...Plunger barrel, 12...Fuel introduction hole. 14...Fuel chamber, 18...Daily delivery valve. 20... Francia, 22... Control rack. 30...Groove, 32...Auxiliary groove, 40...
Actuator, 42... Control valve, 44...
・Vacuum regulating valve, 46...
・Negative pressure source. 48...Temperature sensor.

Claims (1)

[Claims] (1) A plunger barrel that has a fuel introduction hole and forms a passage for supplying fuel from the fuel introduction hole to the fuel injection nozzle has an axially inclined groove that communicates with the groove and extends to the upper end surface of the head. In a fuel injection pump for a diesel engine, in which a plunger having a hole is fitted so as to be vertically movable and rotatable, fuel is forcefully injected by the vertical movement of the plunger, and fuel injection amount and fuel injection timing are regulated by the rotational position of the plunger. , an actuator that controls the amount of movement of the control rack in such a way that the effective stroke of the control rack that rotates the plunger in conjunction with the accelerator pedal is maximized at extremely low temperatures, and the effective stroke of the control rack decreases as the temperature increases. The upper end face of the plunger head is formed into an end face inclined in the axial direction, and an auxiliary groove adjacent to the groove and inclined in the axial direction along the inclined face of the upper end face of the plunger head is formed closer to the head side than the groove. The gap between the upper end surface of the plunger head and the auxiliary groove is set so that the fuel injection timing at cryogenic temperatures is later than at high temperatures, and the amount of fuel injection at cryogenic temperatures is larger than at high temperatures. A fuel injection pump for a diesel engine that is characterized by being set to .