JPH0511312Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a boost pressure control device for an internal combustion engine with a turbocharger, and is particularly concerned with backing up failures in the control valve and controlling boost pressure by operating the control valve. This invention relates to preventing a vehicle from being shocked when removing deposits from a control device.

[Conventional technology]

As a conventional boost pressure control device for an internal combustion engine with a turbocharger, there is one shown in FIG. 8, for example. In Fig. 8, 1 is the engine body, 2
is a turbo charger, 3 is a compressor, 4 is a turbine, 5 is a bypass passage, 6 is a waste gate valve, 7 is an air cleaner, 8 is an intake passage, 9 is an exhaust passage, 10 is a throttle valve, 11 is an orifice, 12 is an actuator, 13 is a working pressure chamber, 1
4 is a spring, 15 is a rod, 16 is a diaphragm, 17 is a control valve, 18 is a moving core, 1
9 solenoid coil, 20 control valve internal passage, 2
1 is a fuel injector, 22 is a combustion chamber, 23
is a relief valve, 24 is an intake pressure sensor, 25 is a water temperature sensor, 26 is a knock sensor, 27 is an intake temperature sensor, 28 is a throttle valve opening sensor, 29 is an electronic control device, 30 is a rotation speed detection sensor, 33 is a blow-by gas Passages 34 and 35 are passages.

Boost pressure control is performed as follows. An intake pressure sensor 24 located in the intake passage 8 on the downstream side of the throttle valve 10 detects the pressure of intake air, and a throttle valve opening sensor 28 detects the opening of the throttle valve 10. The detected intake pressure is the set value (however,
If the intake pressure is different from the target pressure when the positive pressure (lower than the valve opening pressure of the actuator 12) and the detected valve opening is higher than the set value, the actuator is opened by duty-controlling the control valve 17. 12 and wastegate valve 6,
Maintain the intake pressure at the target pressure above. The target pressure is
It is predetermined in advance according to the driving state, that is, comprehensively considering factors such as engine speed, throttle valve opening, engine cooling water temperature, knocking state, and vehicle speed, and is stored in the electronic control unit 29. .

As a reference regarding a supercharging pressure control device for a turbocharged internal combustion engine, see Japanese Patent Application Laid-Open No. 60-81425.
There is a publication number.

[Problem that the invention attempts to solve]

However, the conventional supercharging pressure control device for an internal combustion engine with a turbocharger described above has the following problems.

The first problem is that if the solenoid coil 19 of the control valve 17 is disconnected, the control valve 17 will remain in the OFF state, and if the disconnected cord is grounded and shot, the control valve 17 will remain in the ON state. , the intake pressure becomes uncontrollable. For example, if the intake pressure becomes uncontrollable with the switch ON, the intake pressure will rise too much and the engine will knock.

The second problem is that the control valve 17 may be used to remove deposits such as oil that have adhered to the orifice 11 and the control valve internal passage 20 when the vehicle is decelerating. valve 10
The point is that when it opens (when it starts accelerating), it gives a shock to the vehicle at that time.

The reason for the first problem does not require any explanation. The reason for the second problem is that
It is as follows.

First, we will discuss the mechanism by which oil etc. adheres and the harmful effects caused by the deposits, then we will discuss how the control valve 17 is used to decelerate the vehicle to remove the deposits, and finally, we will explain how the control valve 17 is used when decelerating the vehicle to remove the deposits. We will now discuss how opening the valve 10 provides a shock to the vehicle.

Blowby gas flowing from the engine body 1 through the blowby gas passage 33 passes through the compressor 3 and into the orifice 11 and the control valve internal passage 20.
come into the world. Control valve 17 closes (OFF)
), it will naturally accumulate in it. However,
The blow-by gas contains oil and the like, and this oil and the like adhere to the walls of the orifice 11 and the control valve internal passage 20. Even if it adheres, it is sufficient if it is often blown away by the strong air flow that flows when the control valve 17 is opened (turned ON) and taken out through the passage 35. However, strong airflow flows through this area during sudden acceleration or when climbing a steep slope (when the engine is at high revolutions and under high load).
, and not so much during normal driving. As a result, the adhesion progresses rapidly and eventually becomes stuck and deposited. This adhesion and deposits not only impair the durability of the boost pressure control device, but also impair control performance as described below.

If the passage diameter of the orifice 11 or the control valve internal passage 20 is narrowed due to adhesion or deposits, the control valve 17
The amount of air passing through when is turned on is reduced. FIG. 7 is a flow rate characteristic diagram showing the flow rate of air passing through the control valve with respect to the ON duty ratio of the control valve 17.
What used to have properties like A ₂ will become like B ₂ as the adhesion and accumulation progresses, and the same properties will occur.
Even with the ON duty ratio, the amount of air flowing becomes extremely small.

Moreover, the pressure characteristics are also deteriorated. Figure 6 shows control valve 1
This is a pressure characteristic diagram showing the internal pressure of the working pressure chamber 13 with respect to the ON duty ratio of 7. Initially, the characteristic was like _A1 , but as the sticking and accumulation progressed, it became the characteristic like _B1. , the variable range, that is, the adjustment range of the pressure in the working pressure chamber 13 becomes narrower. Therefore, even if an attempt is made to raise the intake pressure to the target pressure by operating the control valve 17, a situation may arise in which the intake pressure cannot be raised. That is, the power performance of the engine gradually deteriorates as the adhesion and accumulation progresses.

Furthermore, if the amount of stuck/deposited material becomes large, when the control valve 17 is opened to the maximum extent, that is, when the moving core 18 is moved to the left as much as possible in FIG. , its stickiness makes it difficult to return to its original shape (that is, it becomes difficult to close). In this case, the flow rate characteristics become as shown in C ₂ in FIG. 7, and more air flows than necessary. In addition, the pressure characteristics are such that there are parts where the pressure in the operating pressure chamber changes greatly in response to a slight change in the ON duty ratio, as shown in C ₁ in FIG. A large change in the pressure in the working pressure chamber 13 causes fluctuations in the intake pressure and engine speed.

Next, the process of opening the control valve 17 and removing deposits when the vehicle decelerates will be described. Conventionally, the control valve 17 was not used during vehicle deceleration without fuel injection. Therefore, focusing on this point, the control valve 17 is opened during an appropriate period when the vehicle decelerates, and the orifice 1
1. It is conceivable to flush out the deposits with a strong air flow through the passage 34, the control valve internal passage 20, and the passage 35. In that case, since it is not preferable to apply a shock to the vehicle when opening or closing the control valve 17, it is necessary to detect whether the operating state is such that no shock is applied to the vehicle at those times. Also, in order to flush out deposits, the intake pressure must be higher than atmospheric pressure, so
This also needs to be detected.

Next, the control valve 17 is opened to flush out the deposits, and the throttle valve 10 is opened.
The reason why the vehicle is shocked will be described. When the control valve 17 is turned on during deceleration of the vehicle, the rate at which the intake pressure in the intake passage 8 between the compressor 3 and the throttle valve 10 decreases over time is slower than when the control valve 17 is not turned on. This is because
When it is turned on, the wastegate valve 6
This is because there is no longer enough positive pressure to open the throttle valve 10, so the exhaust gas cannot be led into the bypass passage 5, and the rotation of the turbine shaft of the turbocharger 2 cannot be decelerated. As a result, the intake pressure in the intake passage 8 between the compressor 3 and the throttle valve 10 is difficult to reduce. If the throttle valve 10 is opened in this state, high-pressure air is suddenly sent into the combustion chamber 22. Then, the torque of the engine, which had been negative until then, suddenly turns into an excessively positive torque, causing a shock to the vehicle.

The above are the problems and the reasons why they occur, and the present invention aims to solve the above-mentioned problems.

[Means for solving the problem]

In order to solve the above-mentioned problems, in the present invention, an auxiliary control valve is provided in a boost pressure control device for an internal combustion engine with a turbocharger, which opens and closes in response to a command signal and directly transmits intake pressure to the drive unit of the wastegate valve. .

[Effect]

The auxiliary control valve that opens and closes in response to a command signal and directly transmits the intake pressure to the wastegate valve drive unit is the control valve 17 that is used when the vehicle decelerates to remove deposits.
When used at the same time (turned ON), it is possible to eliminate the adverse effect caused by the use of the control valve 17, which gives a shock to the vehicle when the throttle valve 10 is opened. Furthermore, if the control valve 17 is activated when the intake pressure becomes high due to a failure, the wastegate valve can be driven despite the failure of the control valve 17, and knocking can be prevented.

〔Example〕

FIG. 1 shows an embodiment of the present invention. The same reference numerals as in FIG. 8 refer to the same components as in FIG. 32 is a vacuum switching valve which is an auxiliary control valve. The vacuum switching valve 32 is activated by a command from the electronic control device 29.
This is a valve that switches the passage by controlling ON and OFF. When it is OFF, the operating pressure chamber 13
Air is supplied from the orifice 11. ON
When , intake pressure is supplied through the passage 36. Vacuum switching valve 32
is controlled so that it turns on when the control valve 17 is turned on, and turns off when it turns off.

When the vacuum switching valve 32, which is an auxiliary control valve, is used to eliminate the adverse effects caused by the control valve 17 operated to remove deposits, the following procedure is performed.

The timing of opening and closing the control valve 17 when the vehicle decelerates must be determined by taking into consideration whether the opening and closing will not cause a shock to the vehicle and whether the intake pressure is at a predetermined level. An example of this is as follows. It is as follows.

When the control valve 17 is opened (ON duty ratio 100
%)...When the throttle valve 10 is fully closed within a predetermined time, and in that case, the engine speed and vehicle speed are each greater than the predetermined values.

The point in time when the control valve 17 is closed (OFF)...When the throttle valve 10 is opened, or when the engine speed and vehicle speed are no longer above predetermined values.
Alternatively, when the throttle valve 10 is closed and the engine speed and vehicle speed are each at or above a predetermined value for a predetermined period of time or more.

FIG. 2 is a flow chart of the control valve 17 and vacuum switching valve 32 in this case. The numbers ~ in the explanation in this section below correspond to the processes ~ shown in FIG. 2.

The detected throttle valve opening θ is the predetermined valve opening θ ₀
(For example, 60°) Proceed to processing only when the angle is larger than 60°.

Proceed to processing only when the speed at which the throttle valve closes is greater than a predetermined value (for example, 100°/sec).

The time _t0 set according to the throttle valve opening degree θ is allowed to elapse, and then the process proceeds.

Once the throttle valve 10 is fully closed, proceed to processing.

The engine speed is a predetermined value (for example,
Proceed to processing only when the speed is 2500RPM) or higher.

The process proceeds only when the vehicle speed is equal to or higher than a predetermined value (for example, 50 km/h).

Control valve 17 is opened. In other words, processing~
is the ON condition for the control valve 17.

' Vacuum switching valve 32 is ON
be done.

The process proceeds only when the throttle valve 10 is closed. If opened, the process proceeds and the control valve 17 is immediately closed (turned OFF).

The engine speed is a predetermined value (for example,
1700RPM) or higher, proceed to processing.

The process proceeds only when the vehicle speed is equal to or higher than a predetermined value (for example, 35 km/h).

Set a predetermined time t ₁ with a timer (e.g. 100ms)
is set, and after that time has elapsed, proceed to processing.

T is a parameter indicating the number of times the throttle valve opening, engine speed, or vehicle speed has been detected (sensed), and 1 is added to this T.

The number of sensing times is a predetermined number (for example, 10
) is reached. If it has not reached the target, return to the process and repeat sensing again. If it has been reached, the process proceeds and the control valve 17 is closed (turned OFF).

Control valve 17 is closed.

' Turn off the vacuum switching valve 32.
do.

Clear the sensing frequency parameter T and set it to 0.

Note that processing ~ is a process performed to detect the point in time when the intake pressure reaches a predetermined positive pressure. Also,
Processing ~ is inserted for a given time,
This is because if the control valve 17 had been turned on, sufficient air would have flowed to wash out the deposits, so the control valve 17 was turned off.

FIG. 3 shows a case where a detection signal of the intake pressure is used as a determining factor for the timing of opening and closing when the control valve 17 is opened and closed during vehicle deceleration. The difference from FIG. 1 is that a boost pressure sensor 31 is provided upstream of the throttle valve 10 in the intake passage 8. In this example, the timing at which the control valve 17 is opened (ON) and the timing at which it is closed (OFF) are determined as follows.

When the control valve 17 is opened (ON duty ratio 100
%)...The throttle valve 10 is fully closed, the engine speed and the vehicle speed are each higher than predetermined values, and the boost pressure is at a first predetermined value sufficient to cause a strong airflow (for example, 400mmHg).

The point in time when the control valve 17 is closed (OFF)...The throttle valve 10 is opened, the engine speed and the vehicle speed are no longer above the predetermined values, or the boost pressure falls below a second predetermined value (for example, 300 mmHg). When I lost it.

FIG. 4 is a flow chart of the control of the control valve 17 and vacuum switching valve 32 in this case. The process is related to boost pressure. The difference from the previous example is that in order to detect whether the intake pressure has reached a predetermined positive pressure, an element of supercharging pressure detection is introduced instead of a time element using a timer. The reason why the control valve 17 is turned off when the pressure drops below the second predetermined value is that there is no force to flush out the deposits at a pressure below that value.

If the vacuum switching valve 32 is used to prevent the solenoid coil 19 from being disconnected or shot, causing the control valve 17 to remain in the ON state and making it impossible to control the intake pressure, please refer to Fig. 5. The vacuum switching valve 32 may be controlled according to the procedure shown. If the engine becomes uncontrollable while it is in the ON state, the intake pressure will rise. If this happens, the engine will knot and cause damage. Therefore, when it is detected that the intake pressure has become higher than a predetermined pressure, the vacuum switching valve 32 is turned on. Then, the actuator 12 can be brought into an operating state regardless of the control valve 17. If the actuator 12 can be operated, the intake pressure can be lowered.

The present invention can also be applied to a system that determines the fuel injection amount by detecting the intake air amount, and even if the intake pressure control method is different, the actuator's operating pressure chamber pressure can be changed using the control valve. Any type of control device can be applied.

[Effect of idea]

As mentioned above, the supercharging pressure control device for a turbocharged internal combustion engine of the present invention is equipped with an auxiliary control valve that opens and closes in response to a command signal and directly transmits the intake pressure to the wastegate valve drive unit. It is possible to remove deposits in the boost pressure control device by operating the control valve without giving a shock to the vehicle.

Furthermore, even if the control valve fails, the auxiliary control valve backs it up and enables the wastegate valve to be controlled, thereby preventing a situation where the intake pressure cannot be controlled and knocking occurs.

[Brief explanation of the drawing]

Fig. 1... A diagram showing an embodiment of the present invention, Fig. 2... A flow chart related to Fig. 1, Fig. 3... A diagram showing another example of an embodiment of the present invention, Fig. 4... A flow chart related to Fig. 3. Chart, Fig. 5... Flow chart when using the auxiliary control valve to prevent knocking, Fig. 6... Pressure characteristics diagram of the boost pressure control device, Fig. 7
Fig. 8: Flow rate characteristic diagram of a supercharging pressure control device, Fig. 8: Conventional supercharging pressure control device. In the figure, 1 is the engine body, 2 is the turbocharger, 3 is the compressor, 4 is the turbine, and 5 is the
is a bypass passage, 6 is a waste gate valve, 7 is an air cleaner, 8 is an intake passage, 9 is an exhaust passage, 10
1 is a throttle valve, 11 is an orifice, 12 is an actuator, 13 is an operating pressure chamber, 14 is a spring, 15 is a rod, 16 is a diaphragm, 17
18 is a moving core, 19 is a solenoid coil, 20 is a control valve internal passage, 21 is a fuel injector, 22 is a combustion chamber, 23 is a relief valve, 24 is an intake pressure sensor, 25 is a water temperature sensor, 26 is a Nok sensor, 27 is intake temperature sensor,
28 is a throttle valve opening sensor, 29 is an electronic control device, 30 is a rotation speed detection sensor, 31 is a boost pressure sensor, 32 is a vacuum switching valve, 3
3 is a blow-by gas passage, and 34, 35, and 36 are passages.

Claims (1)

[Scope of utility model registration request] A wastegate valve that bypasses exhaust gas to the turbine of the turbocharger, a drive section of the wastegate valve, and a path that diverts intake air supplied from a position downstream of a compressor of the turbocharger to the drive section to a position upstream of the compressor. , and a control valve that drives the wastegate valve in a direction to close it when the wastegate valve is opened.
means for detecting whether conditions are met that will not cause a shock to the vehicle even when the control valve is opened; means for detecting that the intake pressure is positive; and means for detecting whether the conditions are met and the intake pressure is positive. means for issuing a command to open the control valve at a certain time; and an auxiliary control valve that directly transmits the intake air to a drive section of the wastegate valve so that the wastegate valve is not closed when the control valve is opened during vehicle deceleration. A supercharging pressure control device for an internal combustion engine with a turbocharger, characterized in that it is provided with: