JPH0236911Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) The present invention relates to an exhaust throttle valve control device for a vehicle engine, and particularly to an exhaust throttle valve control device suitable for heating the vehicle while the vehicle is running. (Prior art) When using a vehicle engine, especially a diesel engine, which has good combustion efficiency and releases a small amount of heat to cooling water and the outside, as a heat source for heating the vehicle,
The exhaust passage is provided with an exhaust throttle valve, and the exhaust passage is throttled by the throttle valve during heating to apply a load to the engine, thereby increasing the amount of fuel supplied or the amount of heat generated. However, this exhaust throttle valve
While it is effective in increasing the heating effect of the engine, it also works to increase the back pressure of the engine and reduce the output, especially if the opening degree of the throttle valve is fixed at a constant value during heating. When the engine speed increases, the back pressure becomes higher than necessary, and as a result, the required output cannot be obtained at high engine speeds.
This deteriorates the driving performance of the vehicle. Therefore, it is possible to adjust the opening degree of the exhaust throttle valve according to the engine speed, and as a way to do this mechanically with a simple configuration, it is possible to use the back pressure or intake negative pressure of the engine. It will be done. In other words, the former uses a pressure actuator as the actuator for operating the exhaust throttle valve, and a pressure regulating device in which back pressure is introduced from the upstream side of the exhaust throttle valve in the exhaust passage to adjust the operating pressure introduced into the actuator from a pressure source. When the back pressure increases as the engine speed increases, the opening degree of the exhaust throttle valve is increased via the actuator. However, according to this method, the pressure regulating device through which back pressure is introduced from the exhaust passage or the back pressure introduction passage leading to the device is easily clogged with carbon, oil, moisture, etc. in the exhaust gas, so the required durability cannot be achieved. It has the disadvantage of not being reliable and reliable. In addition, the latter introduces engine intake negative pressure as operating pressure into a pressure-type actuator for operating the exhaust throttle valve, and uses the increase in negative pressure as the engine speed increases to adjust the opening of the exhaust throttle valve. It is designed to increase the . According to this method, since clean air before combustion is introduced into the actuator, the problem of clogging as described above does not occur. However, the above actuator is configured to operate the exhaust throttle valve in the opening direction against a spring etc. when the intake negative pressure increases, so if the negative pressure leaks due to an abnormality in the intake negative pressure passage, the exhaust throttle valve The valve is actuated in the closing direction by the spring or the like, and as a result, the engine output is significantly reduced or the engine stalls. In other words, when an abnormality occurs, there is a risk that the system will become inoperable, which violates the so-called fail-safe principle. According to Japanese Patent Publication No. 51-19096, an invention is disclosed in which the exhaust pipe is equipped with a valve to narrow the exhaust gas flow path, but this prevents the emission of blue smoke during no-load operation. However, it is not possible to perform control such as adjusting the opening degree of the exhaust gas passage in a constricted state according to the engine speed. (Purpose of the invention) The present invention addresses the above-mentioned problems regarding the exhaust throttle of a vehicle engine, especially the exhaust throttle for the purpose of heating the vehicle while the vehicle is running. By automatically adjusting the temperature using a simple mechanical configuration, it is possible to heat a vehicle while it is running without significantly increasing costs or deteriorating running performance.
Another object of the present invention is to realize an exhaust throttle valve control device that has excellent durability and reliability and can continue operation even in the event of a failure. (Structure of the invention) The present invention is characterized by the following structure in order to achieve the above object. That is, an exhaust throttle valve is provided in the exhaust passage of the engine,
In an exhaust throttle valve control device for a vehicle engine that controls the throttle valve to an intermediate opening degree, that is, a half-throttled state in a predetermined operating state, a pressure passage from a pressure source to a pressure actuator that operates the exhaust throttle valve is controlled. In addition to providing a pressure valve, the pressure regulation value of the operating pressure by the pressure regulating valve is adjusted by the intake negative pressure of the engine, and when the engine speed increases and the intake negative pressure increases, the operating pressure introduced into the actuator is exhausted. The configuration is such that correction is made in the direction of increasing the opening degree of the throttle valve. According to such a configuration, the opening degree of the exhaust throttle valve is automatically adjusted according to the engine speed during running heating when the exhaust throttle valve is in a half-throttled state, and when the opening degree is constant, the engine speed increases. This prevents deterioration in driving performance due to an increase in back pressure as a result of this, and since intake negative pressure is used for control, problems such as clogging are prevented. In addition, the actuator is configured to operate in the direction in which the opening degree of the exhaust throttle valve decreases when the operating pressure increases, which means that the exhaust throttle valve can be fully opened when a pressure supply abnormality occurs. It is also possible to continue operation. (Example) Hereinafter, an example of the present invention will be described based on the drawings. This embodiment concerns a diesel engine, and as shown in FIG. 1, the combustion chamber 2 of the engine 1 includes an intake passage 4 led from an air cleaner 3, and an exhaust passage 5 whose tip is open to the atmosphere. are communicated with each other via an intake valve 6 and an exhaust valve 7, respectively, and a fuel injection nozzle 8 for supplying fuel to the combustion chamber 2 is provided. In addition, the intake passage 4
There is an intake throttle valve 9 in the interior, and an exhaust throttle valve 1 in the exhaust passage 5.
0 are respectively provided, and these control devices 11 are also provided. This control device 11 includes a vacuum pump 12
A first actuator 13 that operates the intake throttle valve 9 and a second actuator 14 that operates the exhaust throttle valve 10 are provided. , a first solenoid 21 that blocks the passage 15 and communicates the atmosphere release part 15a with the first actuator 13 in the OFF state shown in the figure, and closes the atmosphere release part 15a and communicates the passage 15 in the ON state. is installed. Further, a negative pressure adjustment passage 16 and a negative pressure direct passage 17 are provided between the vacuum pump 12 and the second actuator 14, and the negative pressure adjustment passage 16 is in the OFF state shown in the figure. When the negative pressure adjustment passage 16 is in communication with the second solenoid 22, which blocks the passage 16 and opens the atmosphere release part 16a, and closes the atmosphere release part 16a and communicates the passage 16 when turned on, A negative pressure regulating valve 18 for regulating the negative pressure within the passage 16 is provided. This negative pressure regulating valve 18 is configured such that when the negative pressure within the negative pressure regulating passage 16 increases above a certain level, the valve body 18a
The negative pressure is diluted by opening the atmosphere inlet 18c against the pressure 8b, and when the negative pressure decreases, the valve element 18a is moved by the spring 18b to open the atmosphere inlet 1.
8c, and thus acts to adjust the negative pressure in the negative pressure adjustment passage 16 to a value corresponding to the set load of the spring 18b. Then, the negative pressure adjustment passage 1 is placed in the OFF state shown in the figure at the confluence of the negative pressure adjustment passage 16 and the negative pressure direct passage 17.
6 to the second actuator 14 and turn ON
At the same time, the negative pressure direct passage 17 is connected to the second actuator 14.
A third solenoid 23 is installed to communicate with the third solenoid 23. Thus, the set load of the spring 18b in the negative pressure regulating valve 18 is corrected in accordance with the intake negative pressure in the intake passage 4. That is, the spring 18b in the negative pressure regulating valve 18
A spring receiving member 18d receiving one end is connected to the third actuator 24, and an intake negative pressure introducing passage 25 is provided between the actuator and the intake passage 4 of the engine 1, and the engine rotation speed is When the intake negative pressure increases with the rise of the air pressure, the actuator 24 is actuated to move the spring receiving member 18d in a direction that reduces the set load of the spring 18b. Next, according to FIG. 2, the control circuit 3 of the first to third solenoids 21 to 23 in the control device 11
0, the circuit 30 includes a power supply 3
1 and the circuit 30 as a main switch, and an exhaust brake switch 33 that is turned on by manual operation during exhaust braking.
Also, it is turned ON during warm-up and heating by manual operation.
The warm-up heating switch 34 is turned on when the accelerator pedal is released, and the contacts 35a and 35b are turned on when the accelerator pedal is released.
Accelerator switch 3 closes and opens contact 35c
5, a neutral switch 36 that turns on when the transmission is in neutral, opens contact 36a and closes contact 36b, and when the clutch is connected.
A clutch switch 37 that is turned on, and an acceleration switch 38 that is turned off when the accelerator pedal is pressed a certain amount or more for acceleration are provided. and,
When the accelerator switch 35 is turned on (when the accelerator pedal is released), the first line 41 is connected and the first solenoid 21 is turned on via the diode 45.
Then, the exhaust brake switch 33 is turned on again.
Accelerator switch 35 is turned on, contact 35a is closed, neutral switch 36 is turned off, contact 36a is closed, and clutch switch 37 is turned on.
When this occurs, the second line 42 is connected, and the first solenoid 21 is turned on via the third solenoid 23 and the diode 46, respectively. Also, the warm-up heating switch 34 is turned on, and the accelerator switch 35 is turned on.
When the contact 35b is closed and the neutral switch 36 is turned on and the contact 36b is closed, the third line 43 is connected, and the first and third solenoids 21, 23 is
The warm-up heating switch 34 is turned on, and the warm-up heating switch 34 is turned on.
When the accelerator switch 35 is OFF (when the accelerator pedal is depressed) and the contact 35c is closed, and when the acceleration switch 38 is ON (the amount of depression of the accelerator pedal is below a certain level), the fourth line 44 is connected to the second The first solenoid 21 is turned on via the solenoid 22 and the diode 47, respectively. Here, this control circuit 30 is provided with a lamp 48 that lights up when the exhaust brake switch 33 is turned on, and a lamp 49 that lights up when the warm-up/heating switch 34 is turned on. According to the above configuration, the first to third solenoids 21 to 23 are turned on and off according to each driving state of the vehicle.
The conditions change and various different conditions of the engine 1 are obtained. Next, this will be explained with reference to the flowchart of FIG. First, during normal driving, that is, the exhaust brake switch 33 and the warm-up heating switch 34 are both OFF.
, and when the amount of depression of the accelerator pedal is at an intermediate level (accelerator switch 35 is OFF and acceleration switch 38 is ON), the first to fourth lines 41 to 44 in the control circuit 30 in FIG. 2 are all cut off. and the first to third solenoids 21 to 23
are all OFF (steps S ₁ , S ₂ ,
All S ₃ C are “NO”). Next, during normal idling when the engine is stopped, that is, the exhaust brake switch 33 and the warm-up heating switch 34 are both OFF, and the accelerator switch 35 is turned OFF.
is ON (when the accelerator pedal is released), the first line 41 in Fig. 2 is connected to the first solenoid 2.
1 turns on (steps S ₁ , S ₂ , S ₃ ,
Run S ₄ ). At this time, negative pressure is introduced into the first actuator 13 shown in FIG. 1, and the intake throttle valve 9 in the intake passage 4 is brought into a half-throttled state. This reduces so-called idling vibration caused by too large an amount of intake air during idling. Further, when the engine 1 is in an idling state and the warm-up heating switch 34 is turned on to promote warm-up, the switch 34 is turned ON and
When the accelerator switch 35 is ON and the contact 35b is closed, and when the transmission is in the neutral state and the contact 36b of the neutral switch 36 is closed, the third line 43 in FIG. 2 is connected, and the first and third solenoids 21, 23 is turned on (steps S ₁ , S ₅ , and S ₆ in FIG. 3 are executed). Therefore, negative pressure is introduced into the first actuator 13 and the intake throttle valve 9 becomes half-throttled, and a large negative pressure is directly introduced into the second actuator 14 from the vacuum pump 12 via the negative pressure direct passage 17. Then, the actuator 14 is lifted to the maximum extent, and the exhaust throttle valve 10 in the exhaust passage 5 is operated from the fully open state shown by the solid line in FIG. 1 to the substantially fully closed state shown by the broken line. As a result, the negative pressure or back pressure of the engine 1 increases, and accordingly, the amount of fuel supplied increases, and the engine 1 is quickly warmed up. Furthermore, when the exhaust brake switch 33 is turned on to obtain engine braking while driving, the switch 33 is turned on, the accelerator switch 35 is turned on, and the contact 35a is closed, and the transmission is in a state other than neutral. position (neutral switch 36 is OFF)
Since the contact 36a is closed, the clutch is connected, and the clutch switch 37 is ON, the second line 42 in FIG. ,23
turns on (steps S ₁ , S ₂ , S ₇ ~
Run S ₁₀ ). Therefore, the first actuator 13
Negative pressure is introduced into the intake throttle valve 9 so that the intake throttle valve 9 is in a half-throttled state, and at the same time, a large negative pressure is directly introduced into the second actuator 14 from the negative pressure direct passage 17, and the exhaust throttle valve 10 is opened as shown by the broken line in FIG. It is almost fully closed as shown. This increases the back pressure of the engine 1 and provides the required exhaust brake. Note that even if the exhaust brake switch 33 is turned on, if the accelerator pedal is depressed, the accelerator switch 35 is turned OFF and the contact 35a is opened, thereby canceling the exhaust brake operation as described above. Step _S7 in Figure 3 is “NO”). Also, when the accelerator pedal is released and the accelerator switch 35 is ON, when the transmission is shifted to neutral and the contact 36a of the neutral switch 36 is opened, and when the clutch is disengaged and the clutch switch 37 is turned OFF. When this occurs, the exhaust brake operation is canceled and only the first solenoid 21 is turned on (steps _S8 or _S9 to step _S4 in FIG. 2 are executed). In other words, when the engine 1 is under no load, the intake throttle valve 9 is in a half-throttled state, and vibrations of the engine 1 similar to the above-mentioned idle vibrations are reduced. However, when the warm-up heating switch 34 is turned on to heat the vehicle during normal running of the vehicle, the switch 34 is turned on, and the amount of depression of the accelerator pedal is about halfway, and the accelerator switch 3 is turned on.
5 is OFF, the contact 35c is ON, and the acceleration switch 46 is also ON, so the fourth line 44 in FIG. 2 is connected, and the first and second solenoids 21, 22
turns on (steps S ₁ , S ₅ , S ₁₁ ,
Run S ₁₂ ). At this time, in FIG. 1, negative pressure is introduced into the first actuator 13, the intake throttle valve 9 becomes a half-throttled state, and the second actuator 1
Negative pressure is introduced into the actuator 4 from a negative pressure adjustment passage 16, but the negative pressure in the passage 16 is adjusted by the negative pressure adjustment valve 18 to a negative pressure corresponding to the set load of the spring 18b. The lift amount of 14 is smaller than that during the above-mentioned stop/warm-up or exhaust braking, and the opening degree of the exhaust throttle valve 10 becomes an intermediate opening degree, that is, a half-throttle state shown by the chain line in FIG. In this state, the third actuator 2
The intake negative pressure of the engine 1 introduced into the engine 4 is shown in Figure 4 1.
As shown in FIG. 2, the set load of the spring 18b on the negative pressure regulating valve 18 becomes smaller as the engine speed increases, and the atmospheric air is more easily introduced into the regulating valve 18. The negative pressure in the negative pressure regulating passage 16 by the valve 18, that is, the pressure regulation value of the negative pressure introduced into the second actuator 14 decreases as shown in FIG. 42. Therefore,
When the engine speed increases, the opening degree of the exhaust throttle valve 10, which is in the half-throttled state, increases as shown in FIG. 4. As a result, despite the increase in the rotational speed of the engine 1, the back pressure is kept approximately constant as shown in FIG. This will prevent deterioration of driving performance at times. In that case, the second actuator 14 is introduced, but as the negative pressure decreases, the spring 14a operates to increase the opening degree of the exhaust throttle valve 10. When the introduction of negative pressure to the exhaust throttle valve 14 is stopped, the exhaust throttle valve 10 is operated to the fully open position by the spring 14a. Therefore, it is possible to continue operating the engine 1 even when a failure occurs. In addition, if the accelerator pedal is depressed more than a certain amount to accelerate the vehicle while the vehicle is being heated, the acceleration switch 38 shown in FIG. The operation is canceled (step _S11 in FIG. 3 is "NO"). As a result, the intake passage 4 and the exhaust passage 5 are fully opened, and the output necessary for acceleration is obtained. Note that Table 1 summarizes the respective running states of the vehicle and the ON/OFF states of the first to third solenoids 21 to 23.

【table】

[Table] (Effects of the invention) As described above, according to the invention, in a vehicle engine that heats the vehicle during running by controlling the exhaust throttle valve provided in the exhaust passage to an intermediate opening degree, Since the opening of the throttle valve during running heating is automatically adjusted according to the engine speed using the engine's intake negative pressure, an increase in back pressure due to an increase in engine speed is prevented, and heating is improved. Good driving performance can also be obtained inside. In particular, according to the present invention, there is no need to complicate the configuration as would be the case when adjusting the opening of the exhaust throttle valve electrically, and there is no need for clogging of the adjusting device when back pressure is used for control. It is possible to realize a device that does not cause any malfunctions, can continue to operate even in the event of a failure, is excellent in cost, reliability, durability, etc., and satisfies so-called fail-safe conditions.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Fig. 1 is a control system diagram, Fig. 2 is an electric circuit diagram of the control device, Fig. 3 is a flowchart showing the operation, and Fig. 4 is a diagram of the control system.
1 to 4 are graphs showing the same effect. 1... Engine, 5... Exhaust passage, 10... Exhaust throttle valve, 12... Pressure source (vacuum pump),
14... Actuator, 16... Pressure passage (negative pressure adjustment passage), 18... Pressure regulation valve (negative pressure regulation valve).

Claims (1)

[Scope of utility model registration request] In an engine exhaust throttle valve control device that includes an exhaust throttle valve in the exhaust passage of the engine and controls the throttle valve to an intermediate opening degree in a predetermined operating state, pressure is applied from a pressure source to a pressure actuator that operates the exhaust throttle valve. A pressure regulating valve is provided in the passage, and the pressure regulating value by the pressure regulating valve is controlled in a direction in which the opening degree of the exhaust throttle valve increases when the negative pressure increases due to the intake negative pressure of the engine. Exhaust throttle valve control device for vehicle engines.