JPS6128030Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection pump for a diesel engine, and more particularly to a fuel injection device for smoothing a diesel engine's sensitive response to accelerator pedal operation.

In a diesel engine equipped with a fuel injection device, the response to the amount of operation of an accelerator pedal is generally sensitive, and the output of the diesel engine tends to change rapidly. For this reason, in vehicles equipped with such diesel engines, if the accelerator pedal is suddenly operated, the sudden acceleration may cause an unpleasant shock to the occupants, especially when starting the vehicle, and the shock may cause an unpleasant shock to the occupants. The reduction in the amount of accelerator operation and the torsional vibration of the drive system induce periodic changes in the engine speed, causing a problem in that the vehicle longitudinally vibrates.

On the other hand, as described in Japanese Patent Application Laid-Open No. 112827/1982, we focused on the engine rotation speed that increases in accordance with the amount of accelerator depression, and expressed the accelerator signal representing the amount of accelerator depression and the engine rotation speed. A device has been considered that retards the fuel injection timing depending on the magnitude of the deviation value from the rotation signal.
According to this, when the load is large, such as when the vehicle starts, the deviation value increases and the fuel injection timing is retarded, so that the longitudinal vibration of the vehicle that accompanies the unpleasant shock when the vehicle starts is eliminated. However, even when the vehicle is running uphill or when a sudden acceleration operation is performed while driving, the deviation value increases and the injection timing is retarded. The drawback was that sufficient output could not be obtained.

The present invention was developed against the background of the above-mentioned circumstances, and its gist consists of a cylinder bore, a timer piston that is slidably fitted into the cylinder bore and forms a low pressure chamber and a high pressure chamber on both sides, and a timer piston that connects the timer piston to the high pressure chamber. A spring biased toward the chamber side, and according to the pressure difference generated between the low pressure chamber and the high pressure chamber as the engine rotates,
The timer piston is moved to a position where the differential pressure acting on the timer piston and the biasing force of the spring are balanced, and the timer piston is moved so that as the pressure difference increases, the fuel injection timing is advanced. A fuel injection device for a diesel engine that pumps fuel to a diesel engine at a time corresponding to a moving position includes: (1) a passage that communicates between the low pressure chamber and the high pressure chamber; and (2) a passage that communicates with the low pressure chamber and the high pressure chamber; (3) an accelerator operation detector that detects the accelerator operation signal and generates an accelerator operation signal when the accelerator pedal is operated; a signal delay device that outputs the accelerator operation signal after a certain period of time; (4) a signal delay device that is inserted in the passage and opens the passage when the accelerator operation signal is not supplied from the signal delay device; The reason is that an on-off valve is provided to close the passage when the passage occurs.

Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

In FIG. 1, an injection pump 2 serving as a fuel injection device includes a drive shaft 6 rotatably supported by a housing 4 and rotationally driven by a diesel engine (not shown). The drive shaft 6 has a fuel reservoir chamber 8 inside the housing 4.
Rotor 1 of vane-type pump 10 that supplies fuel to
2 and a timing gear 14 are fixed, and a pump plunger 16 is connected in the axial direction. The pump plunger 16 is rotatable together with the drive shaft 6 and connected to the drive shaft 6 via a shaft joint (not shown) so as to be movable in the axial direction.

Further, a roller plate 20 is provided on the support wall 18 of the housing 4 so as to be rotatable around the axis of the drive shaft 6 . A plurality of rollers 22 are arranged at equal angular intervals on the surface of the roller plate 20 facing the pump plunger 16.
A cam plate 24 fixed to the pump plunger 16 is urged by a return spring 26 and brought into contact with these rollers 22 . Therefore, when the drive shaft 6 is rotationally driven, the pump plunger 16 is given a rotational motion to rotate together with the drive shaft 6 and a reciprocating motion in the axial direction.

Pump plunger 16 has a complex fuel passage 28
is formed, and the fuel sucked from the fuel reservoir chamber 8 through the suction passage 30 by the above-mentioned movement of the pump plunger 16 is fed under pressure to the injection valve of the diesel engine (not shown) through the discharge passage 32 and the delivery valve 34. It is becoming more and more like this. Furthermore, the first
The figure shows only one typical system of discharge passages 32 and delivery valves 34, but they are provided in the same number as the number of cylinders in a diesel engine.

The timing at which fuel is pumped to the injection valve by the pump plunger 16, that is, the fuel injection timing is as follows:
roller plate 20 by timer piston 36
can be changed by rotating the . That is, the tip of the adjustment arm 38 extending radially from the outer circumference of the roller plate 20 is engaged with a recess provided in the timer piston 36.
The axial movement of the timer piston 36 causes the roller plate 20 to rotate, thereby changing the timing at which the pump plunger 16 is advanced via the cam plate 24.

The timer piston 36 is slidably fitted into a cylinder bore 40 formed in the housing 4 in the circumferential direction of the roller plate 20.
The low pressure chamber 42 of the cylinder bore 40 divided by 6 is connected to the suction port of the vane pump 10 by a conduit 44, and the high pressure chamber 46 is connected to a passage 50 with an orifice 48 in the timer piston 36.
It is communicated with the fuel reservoir chamber 8 via. A spring 51 is inserted into the low pressure chamber 42 to constantly bias the timer piston 36 toward the high pressure chamber 46 .

A passage 52 is provided between the high pressure chamber 46 and the low pressure chamber 42 to communicate them, and this passage 52 has a solenoid valve 54 that opens and closes the communication state between the high pressure chamber 46 and the low pressure chamber 42. is inserted.

On the other hand, a cam 58 for detecting whether or not the accelerator pedal is operated is fixed to a shaft 56 that rotates in conjunction with the operation of an accelerator pedal (not shown).
A limit switch 60 actuated by the rotation of the cam 58 closes its contact and supplies a voltage signal, which is an accelerator operation signal, from a power source 62 to a delay relay 64, which is a signal delay device.
The delay relay 64 closes its contact after a predetermined period of time after receiving the voltage signal, thereby supplying the delayed voltage signal to the electromagnetic valve 54. That is, cam 5
8 and the limit switch 60 form an accelerator operation detector that detects whether or not the accelerator pedal is operated and generates an accelerator operation signal when the accelerator pedal is operated.

The fuel injection amount is controlled by a spill ring 66, a control lever 68, an actuator 70, and the like. That is, when the control lever 68 is rotated around the pin 72 by the actuator 70, the spill ring 66 is slid in the axial direction on the pump plunger 16, and the spill port 74 provided on the pump plunger 16 is opened. The fuel injection amount is controlled by changing the timing and by changing the length of the forward stroke of the pump plunger 16 that effectively pumps fuel.

The vane type pump 10, timer piston 36, cylinder bore 40, etc. in FIG. 1 are shown in a 90 degree expanded view.

The operation of this embodiment will be explained below.

When a diesel engine (not shown) is operated, the drive shaft 6 is driven to rotate as the diesel engine is operated, so that the pump plunger 16 is rotated and reciprocated, and fuel is sequentially pumped to the diesel engine.

In an idle state in which the accelerator pedal (not shown) is not operated, the cam 58 is in the state shown in FIG. 1, so the limit switch 60 is not operated and the solenoid valve 54 is in an open state. Therefore, the low pressure chamber 42 and the high pressure chamber 46 are communicated with each other.
Since there is no pressure difference between 2 and 46, the timer piston 36 is positioned closest to the high pressure chamber according to the biasing force of the spring 51. Therefore, since the roller plate 20 is rotated to the most retarded side, the timing at which fuel is pumped from the injection pump 2 to the diesel engine is retarded the most.

Next, when the accelerator pedal is operated, the actuator 70 operates accordingly, increasing the fuel injection amount and increasing the rotation of the diesel engine. Conventionally, in such a transient state, the speed of the diesel engine reacts sensitively and increases, causing vibrations of the vehicle back and forth accompanied by an unpleasant shock.

However, in this embodiment, when an accelerator pedal depression operation is performed, the operation is detected and at the same time, the fuel injection timing to the diesel engine is retarded for a certain period of time after that operation. This slows down the diesel engine's response and eliminates the vehicle's longitudinal vibrations.

That is, the cam 5 accompanying the operation of the accelerator pedal
When limit switch 60 is operated by rotation of 8, contacts within limit switch 60 are closed, and a voltage signal from power supply 62, which is an accelerator operation signal, is supplied to delay relay 64. This delay relay 64 transfers the voltage signal to the solenoid valve 5 after a predetermined period of time after the voltage signal is supplied.
4, the solenoid valve 54 does not operate yet during that certain period of time, and the low pressure chamber 42 and high pressure chamber 4
6 are in communication with each other. Therefore, the timer piston 36 is located closest to the high pressure chamber 46, and despite the operation of the accelerator pedal,
Diesel engines are supplied with fuel at a retarded injection timing and gradually increase their speed. Therefore, the vehicle starts smoothly.

After the predetermined period of time has elapsed, a voltage signal is supplied from the delay relay 64 to the solenoid valve 54 and the solenoid valve 54 is activated, thereby closing the passage 52 that communicates the low pressure chamber 42 and the high pressure chamber 46. As a result, the timer piston 36 is driven toward the low pressure chamber 42 by the differential pressure generated between its ends in response to the number of rotations of the diesel engine, and moves to a position where the differential pressure and the biasing force of the spring 51 are balanced. Move up to. Therefore, since the diesel engine receives fuel from the injection pump 2 at a desired injection timing corresponding to its rotational speed, its output is not impaired and desirable drivability of the vehicle is ensured.

The signal delay time of the delay relay 64 corresponds to the time for slowing down the response of the engine; if it is too long, drivability will be impaired, and if it is too short, a shock will easily occur. determined.

As described above, according to this embodiment, the fuel injection timing is retarded for a certain period of time in the transient state of the diesel engine caused by the operation of the accelerator pedal.
During this time, the engine response becomes gentler, eliminating the back-and-forth vibration that accompanies an unpleasant shock when the vehicle starts. Since the time during which the engine response becomes slow is set to be extremely short, the drivability of the vehicle is not impaired.

Furthermore, according to the present embodiment, the fuel injection timing is not controlled in accordance with the deviation value between the accelerator pedal operation amount and the engine rotational speed that increases accordingly, but the fuel injection timing is retarded. Since it is controlled according to the time from the start of accelerator operation, it will not be retarded after the vehicle has started without any longitudinal vibrations, such as when driving uphill or suddenly accelerating while driving, thereby avoiding a drop in output due to retardation. There is an advantage that

Next, another embodiment of the present invention will be described. Incidentally, parts common to those in the above-mentioned embodiments are designated by the same reference numerals, and explanations thereof will be omitted.

In FIG. 2, negative pressure is supplied to a vacuum switch 78 from a vacuum pump 76 which is a negative pressure source. The vacuum switch 78 is a cam 5 that rotates with the operation of an accelerator pedal (not shown).
8, and always outputs atmospheric pressure, but when activated by the cam 58, it outputs a negative pressure signal, which is an accelerator operation signal, to the negative pressure delay valve 80. The negative pressure delay valve 80 includes a throttle 82 and a check valve 84 whose limiting direction is directed toward the vacuum switch 78. When a negative pressure signal is supplied, the negative pressure delay valve 80 outputs the negative pressure signal after a predetermined period of time. It is output to the negative pressure on/off valve 86. The negative pressure on/off valve 86 always opens the passage 52, but when a negative pressure signal is supplied, it closes the valve and opens the low pressure chamber 42 and the high pressure chamber 46.
Cut off communication with.

Therefore, even if a negative pressure signal is supplied to the negative pressure delay valve 80 due to the operation of the vacuum switch 78 in response to the operation of the accelerator pedal, this negative pressure delay valve 8
0, the supply of the negative pressure signal to the negative pressure on/off valve 86 is delayed for a predetermined period of time.
The response of the diesel engine within this certain period of time is made gentler, and the occurrence of longitudinal vibration of the vehicle is prevented. Furthermore, since the timing is retarded by time control from the start of the accelerator operation, there is an advantage that the drivability is maintained without being retarded during sudden acceleration on a climbing road or while driving after the accelerator operation.

Although the embodiment of the present invention has been described above based on the drawings, the present invention can also be applied to other aspects.

For example, delay relay 6 in the above embodiment
4 may be a signal delay device constituted by a timer or a one-shot multi-circuit.

Furthermore, the electromagnetic valve 54 and the negative pressure on/off valve 86 in the above-mentioned embodiment are configured to operate in two positions, fully open or fully closed; Two types of accelerator operation signals delayed by the same time may be supplied.

The above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

As detailed above, according to the diesel engine fuel injection device of the present invention, in the transient state of the diesel engine due to accelerator operation, the fuel injection timing is retarded for a certain period of time after accelerator operation. This slows down the response of the diesel engine for a certain period of time, eliminating the back-and-forth vibration of the vehicle that accompanies the unpleasant shock. Moreover,
Since the engine is not retarded after a certain period of time has elapsed since the accelerator was operated, a decrease in output can be avoided by retarding the engine when the vehicle is running uphill after starting or when performing a sudden acceleration operation while driving.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the configuration of an embodiment of the present invention. FIG. 2 is an explanatory diagram of main parts showing another embodiment of the present invention. 36: timer piston, 40: cylinder bore,
42: Low pressure chamber, 46: High pressure chamber, 51: Spring, 52: Passage, 54: Solenoid valve (on/off valve), 8
6: Negative pressure on/off valve (on/off valve), 58: Cam, 60:
Limit switch (accelerator operation detector), 7
8: Vacuum switch (accelerator operation detector), 64: Delay relay (signal delay device), 80:
Negative pressure delay valve (signal delay device).

Claims (1)

[Claims for Utility Model Registration] An engine engine comprising a cylinder bore, a timer piston that is slidably fitted to the cylinder bore to form a low pressure chamber and a high pressure chamber on both sides, and a spring that biases the timer piston toward the high pressure chamber. According to the pressure difference generated between the low pressure chamber and the high pressure chamber as the timer piston rotates, the timer piston is moved to a position where the differential pressure acting on the timer piston and the biasing force of the spring are balanced, and the pressure is reduced. In a diesel engine fuel injection device that pumps fuel to a diesel engine at a timing corresponding to a movement position of the timer piston so that the fuel injection timing advances as the difference increases, the low pressure chamber and the high pressure chamber an accelerator operation detector that detects whether or not an accelerator pedal is operated and generates an accelerator operation signal when the accelerator pedal is operated; a signal delay device that delays the accelerator operation signal for a predetermined period of time and outputs the accelerator operation signal after the elapse of the predetermined time; A fuel injection device for a diesel engine, comprising: an on-off valve that opens a passage but closes the passage when the accelerator operation signal is supplied.