JPS6165030A - Accelerating device of diesel engine - Google Patents

Abstract

PURPOSE:To raise the transitional responsiveness, by performing the supercharge increase controlling with time-delaying compared with the angle of advance controlling, according to the valve opening speed of an accelerator pedal. CONSTITUTION:A means 19 which outputs an acceleration signal according to the valve opening speed of an accelerator pedal 18, is set, and a delaying means 31 which brings time delay compared with the signal transmission toward a connection controlling device 13 which controls the connecting route between the high pressure side and the low pressure side of a timer piston 7, is set on a signal transmitting route 20b from said means 19 to a fuel supercharge increasing device 2. In this way, as the timer angle of advance controlling is made precede, the transitional responsiveness from the angle of advance controlling to the increase controlling can be raised.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to advance control of a distributed fuel injection pump for a diesel engine, and particularly to an acceleration device that improves acceleration performance and transient response.

2. Description of the Related Art Distributed fuel injection pumps equipped with a fuel boost increaser and a hydraulic timer have been known for a long time, but in the prior art, it is difficult to move the timer piston from the start of acceleration to the required advance angle. It was taking time. Therefore, as shown in FIG. 3, the stroke control of the timer piston is delayed considerably with respect to the advance angle request value A.

In addition, since the fuel amount increase correction is applied using the boost pressure in a steady state, the fuel amount increase after depressing the accelerator pedal during acceleration has a characteristic with respect to the required characteristic C, as shown in Figure 4. I was late as hell. Both of these delays naturally led to deterioration in acceleration performance and transient response. Additionally, delays in advance angle led to misfires and white smoke.

Regarding timer advance angle control, a proposal has been made in which a communication path is provided between the high pressure side and the low pressure side of the timer piston to alleviate pressure fluctuations on the high pressure side, suppress control fluctuations, and improve control responsiveness ( Utility Model Publication No. 55-97137).

Problems to be Solved by the Invention However, the above proposal is related to improving the controllability of the timer, that is, improving the controllability of the injection timing, and when accelerating, where it is desired to match with the fuel increase and improve the controllability of the fuel increase, It is not possible to achieve significant effects in terms of improving acceleration performance and improving transient response.

SUMMARY OF THE INVENTION Therefore, in order to improve acceleration performance, it is an object of the present invention to improve transient response while adapting both fuel injection timing advance control and fuel increase control during acceleration.

Means for Solving the Problems A diesel engine accelerator according to the present invention in accordance with this object includes a fuel supercharging increase device, a communication path between the high pressure side and the low pressure side of the timer piston, and communication control means for the communication path. An acceleration signal generating means corresponding to the opening speed of the accelerator pedal is connected to the fuel supercharging increase device and the communication control means of the distribution type fuel injection pump having a timer, and the fuel supercharging is performed from the acceleration signal generating means. In the signal transmission path to the bulking device,
A delay means is provided for delaying the transmission of the signal relative to the transmission of the signal to the communication control means.

The communication control means is composed of, for example, a negative pressure valve or a solenoid valve, and the acceleration signal generation means is a negative pressure generation device that is moved mechanically with the accelerator pedal, or means that electrically determines acceleration based on the movement of the accelerator pedal, etc. The delay means consists of an aperture provided in the negative pressure circuit, an electrical delay circuit, or the like.

Function In such an acceleration device, the communication control means is actuated by a signal from the acceleration signal generation means, and communication between the high pressure side and the low pressure side of the timer piston is cut off, and the pressure on the high pressure side is increased, so that the timer piston is fully discharged. The movement is controlled quickly and the advance angle is accelerated. Further, in response to this advance angle control, a signal from the acceleration signal generating means is sent to the fuel supercharging increase device with a slight time delay due to the delay means. In response to this signal, the boost pressure is controlled to be higher than the steady state, and the increase correction is quickly started to improve responsiveness.

Therefore, in this control, the transient responsiveness of both fuel injection timing control and fuel increase during acceleration is improved.

In this control, if the fuel increase control precedes the timer advance, there will be an inconvenience that only the fuel will be increased first and white smoke or misfire will occur. Since priority is given to the control timing, the transient response is enhanced so that both the advance angle control and the fuel increase control approach the required characteristics while adapting the control timing.

Embodiments Hereinafter, preferred embodiments of the diesel engine accelerator of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which reference numeral 1 indicates a distribution type fuel injection pump.

This distribution type fuel injection pump 1 is equipped with a fuel supercharging increase device 2 that supercharges and increases the amount of fuel, and a timer 3 that controls fuel injection timing.

The fuel supercharging increase device 2 has a diaphragm valve structure, and controls the fuel increase by moving a bushing rod 6 up and down depending on the balance between the atmospheric pressure chamber 4 and the supercharging pressure 5. In the figure, the amount is increased when the bushing rod 6 moves ``downward''.

The timer 3 has a high pressure chamber 8 and a low pressure chamber 9 of the timer piston 7.
The position of the timer piston 7 is controlled by the balance between the high pressure 8, the fuel pressure in the low pressure chamber 9, and the timer spring 11. The injection timing is controlled via the timer ride bin 12. As shown in FIG. 2, the communication passage 10 is provided with a communication control means 13 for controlling the communication on/off of the communication passage 10 or the flow area of the communication passage. The communication control means 13 consists of a negative pressure valve, and the fuel leak boat 15 is controlled to open and close by the balance between the spring 16 and the negative pressure introduced into the negative pressure chamber 17 by the movement of a rod connected to the bellows 14 that expands and contracts. It is now possible to do so.

The negative pressure v17 of the negative pressure valve 13 is supplied to the accelerator pedal 18.
Acceleration signal generating means 19 is mechanically linked to the movement of the accelerator pedal 18 and generates an acceleration signal according to the opening speed of the accelerator pedal 18.
They are connected via a vacuum hose 20 as a signal transmission path. This signal transmission path 20 is divided into two hoses 20a and 20b in the middle, and is also connected to the atmospheric pressure 4 of the fuel supercharging increase device 2. Acceleration signal generating means 19
In this embodiment, the device is composed of a negative pressure generating device, which generates negative pressure in the negative pressure generating chamber 24 by the movement of a piston 23 slidably inserted into the casing 21 while being biased by a spring 22. It is configured. The piston 23 is connected to the accelerator pedal 18 via a link 25 so as to be mechanically linked to the movement of the accelerator pedal 18. 26 is an orifice provided in the piston 23, which functions as a damper and equalizes the pressure with atmospheric pressure. A check valve 27 opens when the accelerator pedal 18 is released to introduce atmospheric pressure into the negative pressure generating chamber 24. The accelerator pedal 18 includes an accelerator link 28,
It is connected to an accelerator lever 30 of the fuel injection pump 1 via an accelerator wire 29 .

The signal transmission path 20b to the fuel supercharging increase device 2 is provided with a throttle 31 as a delay means for delaying the transmission of negative pressure transmitted as a signal. Furthermore, a throttle 32 and a bimetal negative pressure switching valve (BVSV) 33 are provided in parallel in the signal transmission path 2O before branching into two. B.V.
The SV33 is equipped with a bimetal that operates according to the engine water temperature (for example, water temperature 60''C), and is configured to cut off the negative pressure passage when the engine is warm and open it when the engine is cold.

Note that the negative pressure used as a signal in this example is:
It may also be an electrical signal. That is, the opening and closing of the communication passage 10 is controlled by a solenoid valve, the fuel supercharging increase device is operated electrically (for example, by using a solenoid coil), and the movement of the accelerator lever 30 is controlled as the opening speed of the accelerator pedal 18. A method may also be used in which the speed is detected by a throttle sensor, the detected speed is differentiated to determine acceleration, and a so-called electrical delay circuit is used as the delay means. Further, as the signal itself, negative pressure is used as in this embodiment, and the negative pressure generating device is electrically linked with the accelerator pedal 18. That is, a method may be used in which the valve opening speed is generated as an electrical signal using the method described above, and the negative pressure generator is operated based on the electrical signal.

The operation of the diesel engine accelerator configured as described above will be explained below.

First, by providing the communication passage 10 that communicates the low pressure side of the timer piston 7, pressure fluctuations on the high pressure side are alleviated, control fluctuations are suppressed, smooth operation is achieved, and control responsiveness is improved. This is similar to a conventional device provided with a communication path.

In this embodiment, when the driver depresses the accelerator pedal 18 during acceleration, the accelerator lever 30 is opened by the accelerator wire 29, and at the same time, the piston 23 overcomes the spring 22 by the link 25 and is displaced to the right in FIG. .

Then, negative pressure is generated in the negative pressure generation chamber 24, and this negative pressure is transmitted from the signal transmission path 20. After passing through the throttle 32, the negative pressure is divided into two parts, one of which is introduced into the negative pressure chamber 17 of the negative pressure valve 13. Since the negative pressure chamber 17 has a sealed structure, the bellows 14 expands when negative pressure is introduced, and the fuel leak boat 15
is occluded.

Then, the fuel pressure in the high pressure chamber 8 applied to the timer piston 7 increases because it does not escape to the low pressure side, and the timer piston 7 moves to the left in FIG. 1, that is, in the advance direction. Therefore, when the accelerator pedal 18 is depressed during acceleration, the rise of the timer stroke is advanced so as to approach the required characteristic A shown in FIG. 3, and the transient response of the injection timing advance characteristic is improved.

Further, the other negative pressure is applied to the atmospheric pressure chamber 4 of the fuel supercharging increase device 2 via the throttle 31.

Then, since the atmospheric pressure chamber 4 becomes negative pressure, the bushing rod 6 moves downward in the direction of increasing the amount of fuel.

Since the force due to the negative pressure is applied, the bushing rod 6 is moved faster than in the steady supercharging state, and the rise of the fuel increase control during acceleration is accelerated so as to approach the required characteristic C shown in FIG. 4. In this fuel increase control, the transmission of negative pressure is delayed by the throttle 31, so a slight delay time is given compared to timer advance control. Because of this delay,
Timer advance control has priority, and control of fuel injection timing to the required advance value is always performed earlier than fuel increase, so there is no misfire or white smoke generation.
Transient responsiveness of both advance angle control and fuel increase control is improved.

Moreover, if the throttle 32 and the BVSV 33 are provided in parallel to the vacuum hose 20 as in this embodiment, the BV
SV33 is cut off to maintain normal negative pressure transmission speed, and when cold, BVSV33 is turned on and the passage area is expanded.
Negative pressure transmission speed is increased. That is, the BVSV 33 is controlled on and off as shown in FIG. 5 according to the engine water temperature, and is turned on when the engine is cold, expanding the negative pressure passage, and as shown in FIG. The responsiveness of the advance angle characteristic F during the interval is improved. The same applies to fuel increase control. As shown in Figure 6, as a result of increasing the responsiveness during cold conditions, there is a slight overshoot at startup, but since the fuel viscosity is high during cold conditions and is insensitive to overshoot, the opening characteristics are affected. There will be no adverse effects.

Effects of the Invention As is clear from the above explanation, according to the present invention, the timer advance and fuel increase can be advanced in conjunction with the accelerator pedal, and by providing a slight delay between the two, inconveniences can be avoided. The effect is that the transient responsiveness of both the injection timing control and the fuel increase control during acceleration can be simultaneously improved without causing this occurrence.

By improving transient response, it is possible to not only improve acceleration performance but also quickly control the required characteristics to prevent misfires and white smoke generation.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a diesel engine accelerator according to one embodiment of the present invention, FIG. 2 is a sectional view of a communication control means section of the device shown in FIG. 1, and FIG. 3 is a relationship between timer stroke and time. Figure 4 is a diagram of the relationship between fuel amount and time. Figure 5 is a diagram of the operating characteristics of the BVSV (bimetal double negative pressure switching valve) of the device in Figure 1. Figure 6 is a timer showing the effect of installing the BVSVe. This is a relationship diagram between stroke and time. 1...Distribution type fuel injection pump 2...Fuel supercharging increase device 3...Timer 4...Atmospheric pressure chamber 5... Supply pressure 6... Bush rod 7... Timer piston 8... High pressure chamber 9... Low pressure to 10... Communication path 13... ...Negative pressure valve 14 as communication control means...
... Bellows 15 ... Fuel leak boat 17 ... Negative pressure to 18 ... Accelerator pedal 19 ... Negative pressure generation as acceleration signal generation means Devices 20.20a, 20b... Vacuum hose 23 as a signal transmission path... Piston 24... Negative pressure generation chamber 25... Link 26... ...Orifth r 27...Check valve 28...Accelerator link 29...Accelerator wire 30...Accelerator lever 31... Aperture 32 as delay means...
・Aperture

Claims (2)

[Claims] (1) The fuel supercharging increasing device of a distribution type fuel injection pump, which includes a fuel supercharging increasing device, a timer having a communication path between the high pressure side and the low pressure side of a timer piston, and communication control means for the communicating path; An acceleration signal generation means for generating an acceleration signal in accordance with the opening speed of the accelerator pedal is connected to the communication control means, and the signal is transmitted to a signal transmission path from the acceleration signal generation means to the fuel supercharging increase device. 1. A diesel engine accelerator comprising a delay means for delaying the transmission of a signal to a communication control means. (2) The communication control means is a negative pressure valve operated by negative pressure, the acceleration signal generation means is a negative pressure generation device linked with an accelerator pedal, and the delay means is a throttle provided in the negative pressure circuit. A diesel engine accelerator according to claim 1.