JPH021465Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention operates a throttle valve installed in the exhaust passage or intake passage and also operates a fuel injection amount increasing mechanism when the cooling water temperature is low in a diesel engine. This invention relates to an improvement of a cooling water temperature raising device that increases the temperature of the cooling water by increasing the temperature of the cooling water.

(Prior art) Diesel engines generally have better combustion efficiency than gasoline engines, but because of this, less heat is given to the cooling water, which makes it difficult to warm up the engine after starting, and even when driving. When a heater that uses cooling water temperature as a heat source is used, there is a problem that its heating performance is poor.

Traditionally, as a countermeasure for such problems,
- There is a device disclosed in Publication No. 17691, which detects engine idling, low speed, and low load operating conditions, and depending on this detects the on/off valve (throttle valve) installed in the exhaust pipe and the fuel The actuator that increases the amount of fuel injected by the injection pump is operated at the same time. According to this device, when the on-off valve is closed during idling, a load is applied to the engine, and
Since the fuel injection amount is increased by the operation of the actuator, the amount of heat generated increases, the combustion chamber temperature rises, and therefore the cooling water temperature also rises.

However, although the above publication proposes the above device as a means of improving warm-up performance and preventing emissions,
It can also be used to improve heating performance.
When the on-off valve is closed during idling and the load increases, the governor mechanism operates in response to increase the amount of fuel.This alone can improve warm-up performance, but the heating performance When trying to raise the cooling water temperature as necessary during driving to improve the engine speed, the governor mechanism alone will not increase the amount of fuel sufficiently even if the on-off valve is closed, so it is especially important to increase the amount of fuel as described above. Additional means will be needed to compensate for fuel shortages.

By the way, when the above device is operated during driving in this way, if the actuator for the on-off valve and the actuator for fuel increase are simultaneously actuated by the actuation signal, there will be a difference in the responsiveness of each actuator to the actuation signal. Inevitably, there will be a difference in response between the on-off valve for each actuator and the fuel injection pump, and a delay in the supply of fuel to the combustion chamber. For this reason, the increase in fuel may not match the increase in load caused by the closing operation of the on-off valve, resulting in a fuel shortage, resulting in a temporary lack of output and a rapid increase in engine speed. The problem was that the number of vehicles decreased, causing shock to drivers and worsening driving conditions.

(Purpose of the invention) The present invention solves these conventional drawbacks and actively raises the cooling water temperature when the engine cooling water temperature is low, thereby improving warm-up performance and heating performance. Moreover, it is an object of the present invention to provide a cooling water temperature increasing device for a diesel engine that does not deteriorate the running condition even if it is operated during driving.

(Structure of the invention) The invention provides a throttle valve in the exhaust passage or intake passage of the engine, and when the engine cooling water temperature is low, the throttle valve is closed and the fuel injection amount increasing mechanism of the fuel injection pump is activated. In a cooling water temperature raising device for a diesel engine, a control device outputs an activation signal for a throttle valve and a fuel injection amount increasing mechanism, and a fuel injection amount increasing mechanism responds to the activation signal of the control device prior to closing the throttle valve. It is equipped with a drive device that operates the In other words, when the above activation signal is received, the throttle valve closes after a predetermined period of time after the fuel injection amount increase mechanism is activated, so that by the time the throttle valve closes, the fuel has already been increased and the output is It is configured to ensure that there will be no shortage.

(Example) In FIG. 1, 1 is an engine body, 2 is an intake passage connected to each cylinder of the engine body 1 via an intake manifold 3, and 4 is an exhaust manifold 5.
This is an exhaust passage connected to each cylinder of the engine main body 1 via.

The exhaust passage 4 is provided with an exhaust throttle valve 6. This throttle valve 6 is a negative pressure type actuator 7.
The actuator 7 is actuated by the throttle valve 6
The diaphragm 7a is connected to the diaphragm 7a, and the negative pressure chamber 7b is provided on one side of the diaphragm 7a and contains a spring 7c. It is designed to operate closed. And the negative pressure chamber 7b
A negative pressure introduction passage 9 for introducing negative pressure from the vacuum pump 8 and an atmospheric pressure introduction passage 10 for introducing atmospheric pressure into the negative pressure chamber 7b, and switching the conduction state of these passages 9 and 10. The actuator 7 is controlled by a three-way solenoid valve 11. The atmospheric pressure introduction passage 10 may be opened to the outside air through a filter, but in the figure, the intake passage 10 is
An atmospheric pressure introduction passage 10 is connected to.

Reference numeral 12 denotes a fuel injection pump, which, as is generally known, is equipped with a pump mechanism and a governor mechanism (not shown) inside, and a control lever 13 is connected to an accelerator pedal (not shown) via a wire 14. When the control lever 13 is rotated by operating the accelerator pedal, the fuel injection amount changes accordingly. Furthermore, in addition to these general fuel adjustment means, a fuel injection amount increasing mechanism using a negative pressure type actuator 15 is provided. The actuator 15 has a diaphragm 15a.
and a negative pressure chamber 15b provided on one side thereof and housing a spring 15c. When the pressure in the negative pressure chamber 15b is reduced to a predetermined value or less, the diaphragm 15a operates, thereby causing the control lever 13 to etc., so that the amount of fuel injected by the fuel injection pump 12 is increased. and,
A negative pressure introduction passage 16 for introducing negative pressure from the vacuum pump 8 into the negative pressure chamber 15b, and a negative pressure chamber 1
Atmospheric pressure introduction port 17 for introducing atmospheric pressure into 5b
and a three-way solenoid valve 18 that switches these conduction states.
Accordingly, the actuator 15 is controlled.

The three-way solenoid valves 11 and 18 respectively communicate negative pressure introduction passages 9 and 16 to the negative pressure chambers 7b and 15b of the actuators 7 and 15 to introduce negative pressure when receiving an activation signal, and at other times. closes the negative pressure introduction passages 9 and 16, and connects the negative pressure chambers 7b and 15 from the atmospheric pressure introduction passage 10 and the atmospheric pressure introduction port 17.
Atmospheric pressure is introduced into b. Also,
The capacity of the negative pressure chamber 7b of the actuator 7 for operating the throttle valve is made larger than the capacity of the negative pressure chamber 15b of the actuator 15 for fuel increase, and thereby the three-way solenoid valves 11 and 18 are switched to the negative pressure introducing state. The time required for the pressure in the negative pressure chamber to be reduced to a predetermined value or less is relatively short in the actuator 15 for fuel increase, and relatively long in the actuator 7 for operating the throttle valve. With these,
A drive device is configured that operates a fuel injection amount increasing mechanism prior to closing the throttle valve 6 in response to an operation signal. The capacity of each negative pressure chamber 7b, 15b is set in advance so that the time difference between the operation of the fuel injection amount increasing mechanism and the closing operation of the throttle valve 6 is about 3 seconds.

The control device that outputs the above-mentioned activation signal is a power source 22
and a switch 21 for raising the temperature of the cooling water connected to the ignition switch 23. This switch 21 is, for example, a manual switch, and the switch 21 is operated by the driver with the ignition switch 23 closed. An activation signal is output when the is closed. The three-way solenoid valves 11 and 18 are connected to the switch 21 in parallel. The three-way solenoid valve 11 on the throttle valve operating side is operated via a rotation speed detection switch 24, which closes only when the engine rotation speed is below a predetermined value, and a load detection switch 25, which closes only when the engine load is below a predetermined value. The throttle valve is connected to the switch 21, so that an activation signal is sent to the throttle valve activation side only when the rotation is relatively low and the load is low. This is done in order to avoid a situation where the throttle valve 6 is closed during acceleration and the acceleration performance deteriorates. Furthermore, the above three-way solenoid valve 1
1 is connected to the ignition switch 23 via the timer 26, and the ignition switch 23
Immediately after the throttle valve 6 is closed, the three-way solenoid valve 11 is always energized for a certain period of time set by the timer 26 to close the throttle valve 6. This is done in order to prevent the throttle valve 6 from rusting due to being not operated for a long period of time, such as during summer.

Figure 2 shows the specific shape of the main parts of the device of the present invention,
Reference numeral 4' denotes an exhaust pipe forming the exhaust passage 4, in which a rotary throttle valve 6 is disposed, and a stopper 3 is attached to the rotation axis of the throttle valve 6 outside the exhaust pipe 4'.
Lever 3 whose rotation range is restricted by 3 and 34
1 is installed. This lever 31 is connected by a wire 32 to a diaphragm of an actuator 7 for actuating the throttle valve. Further, an auxiliary lever 35 is attached to the rotating shaft of the control lever 13 of the fuel injection pump 12.
5 is actuator 1 for fuel increase by rod
It is connected to the diaphragm No. 5. 37 is a tube that connects the actuator 7 for operating the throttle valve and the three-way solenoid valve 11, and 38 is a tube that connects the actuator 15 for fuel increase and the three-way solenoid valve 18.

In this device, the switch 21 is turned on by the driver when the engine is cold after starting, or when the cooling water temperature is low and heating is not effective even when the heater is activated. By being closed, an actuation signal is sent to the actuators 7,15. In response to this, first, the amount of fuel injected from the fuel injection pump 12 is increased by a drive device in which the capacities of the actuators 7 and 15 are made different, and as a result, after a certain time delay, the amount of fuel injected from the fuel injection pump 12 is increased.
is activated to close. Therefore, even if the manual switch 25 is closed during driving, by the time the throttle valve 6 is closed, the output has already been increased to an extent commensurate with the accompanying increase in load. A sudden drop in rotational speed due to shortage is reliably prevented. In a state where the fuel injection amount is increased and the throttle valve 6 is closed in this manner, the amount of heat generated increases and the cooling water temperature rises.

In addition, in this device, in order to prevent exhaust gas from being blown back into the intake system when the exhaust throttle valve 6 is closed, an intake throttle valve 27 is also provided in the intake passage 2, as shown by the two-dot chain line in FIG. The intake throttle valve 27 may be opened and closed substantially in synchronization with the exhaust throttle valve 6. Further, even when the intake air is throttled, a load is applied due to pumping loss, so an intake throttle valve 27 may be provided in place of the exhaust throttle valve 6.

Further, as a mechanism for operating the fuel injection amount increasing mechanism prior to the closing operation of the throttle valve 6, in addition to the above-mentioned embodiment, an orifice for restricting the air flow rate in the negative pressure introduction passage 9 to the actuator 7 for operating the throttle valve may be used. It is also possible to adopt a mechanism in which a switch is provided or the operating timing is electrically controlled.

(Effects of the Invention) As described above, the device of the present invention, when closing the throttle valve in the exhaust passage or the intake passage and operating the fuel increase mechanism in order to improve heating performance, can prevent the throttle valve from closing before closing the throttle valve. Since the fuel injection amount increasing mechanism is activated, even while driving, when the throttle valve is closed, there will be no fuel shortage and shock to the driver, and this will prevent deterioration in driving performance. It is possible.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram showing an embodiment of the device of the present invention, and FIG. 2 is a diagram showing the specific structure of the main parts. 1...Engine body, 2...Intake passage, 4...
Exhaust passage, 6... Throttle valve, 7... Actuator for operating the throttle valve, 11... Three-way solenoid valve, 12...
Fuel injection pump, 15... Actuator for increasing fuel injection amount, 18... Three-way solenoid valve, 21... Switch for increasing cooling water temperature.

Claims (1)

[Scope of utility model registration request] In a cooling water temperature increasing device for a diesel engine, in which a throttle valve is provided in the exhaust passage or intake passage of the engine, and when the engine cooling water temperature is low, the throttle valve is closed and a fuel injection amount increasing mechanism of the fuel injection pump is activated. , a control device that outputs an activation signal for the throttle valve and the fuel injection amount increasing mechanism, and a drive device that activates the fuel injection amount increasing mechanism prior to closing the throttle valve in response to the activation signal of the control device. A diesel engine cooling water temperature raising device featuring: