JPH01253533A - Intake air quantity control device for engine with supercharger - Google Patents

Abstract

PURPOSE:To produce excellent decelerating effect for an engine by, in decelerating the engine, decreasing the opening of a throttle valve or a flow regulating valve in a bypass part to the throttle valve as pressure between a supercharger and a throttle valve in an intake passage becomes higher. CONSTITUTION:An intake passage 12 of an engine E is provided with a turbosupercharger 20 having a compressor 17 to pressurize intake air and a throttle valve 23 to regulate intake air quantity introduced into a combustion chamber 11 respectively. In addition, the intake passage 12 is provided with a bypass part 26 making an intercooler 21 and the throttle valve 23 communicate with a surge tank 25, and the bypass part 26 is provided with a flow regulating valve 28. In decelerating the engine E, a control unit 100 controls the opening of the throttle valve 23 or the flow regulating valve 28 so that their opening may decrease as a pressure detected by a sensor 22 between the supercharger 20 and the throttle valve 23 in the intake passage 12 becomes higher than the atmospheric pressure detected by a sensor 33.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a supercharger disposed in an upstream portion of an intake passage from a throttle valve, and when an engine is in a predetermined operating state, The present invention relates to an intake air amount control device for a supercharged engine, which controls the amount of air passing through a bypass section for a supercharged engine.

(Prior art) As one of the technologies related to intake control in an engine installed in a vehicle, etc., for example, Japanese Patent Application Laid-Open No. 57-124036
As shown in the publication, when the engine is in an idling state, in order to maintain the engine speed at the target idle speed, the portion between the air flow meter and the throttle valve in the intake passage and the part downstream from the throttle valve are In addition to providing a bypass section that communicates with the other parts, a flow rate adjustment valve is provided in this bypass section, and the amount of intake air is controlled by changing the opening operation amount of the meteor adjustment valve, so-called idle rotation speed control. known to do. It is also known that an actuator that drives the throttle valve is provided in place of the bypass section and the flow rate adjustment valve, and when the engine is in an idling state, the actuator changes the opening amount of the throttle valve to control the idle rotation speed. It is being

In engines where such idle speed control is performed, when the engine speed is shifted from a deceleration state where the engine speed is above a predetermined value to an idling state, the engine speed is quickly brought to match the target idle speed. In order to achieve this, normally, when the engine is in a decelerating state, the throttle valve modulation valve is opened by an amount corresponding to the engine cooling water temperature, etc.

On the other hand, in order to improve the filling efficiency of the amount of intake air into the engine, it is also well known to provide a turbo-type, engine-driven, or other type of supercharger that pressurizes intake air in an intake system. When a supercharger is attached to an engine configured to control the amount of intake air passing through the bypass section as described above, the supercharger is disposed in a portion upstream of the throttle valve in the intake passage. The upstream end of the bypass section is opened at a portion of the intake passage between the supercharger and the throttle valve.

(Problem to be Solved by the Invention) However, when the flow rate regulating valve or throttle valve disposed in the bypass section is operated to open even when the engine is in a decelerating state, When the engine is in a deceleration state, the supercharger pressurizes the intake air in the portion of the intake passage between the supercharger and the throttle valve to exceed atmospheric pressure,
The amount of air passing through the flow ff1iJfJ valve or throttle valve may be significantly increased. In particular, this phenomenon occurs particularly in engines equipped with turbo-type superchargers, as the high supercharging capacity is maintained by the inertia of the supercharger even when the engine is forced to decelerate. do.

When the engine is in a deceleration state, if the amount of intake air passing through the flow rate adjustment valve or throttle valve is increased, the effect of lowering the engine speed will be weakened, and not only will a good deceleration feeling not be obtained. In particular, when the power transmission path from the engine to the wheels is cut off due to a gear change operation, etc., and the load imposed on the engine suddenly decreases, the engine speed suddenly increases. There is a possibility that this may occur. Therefore, when the engine is in a deceleration state, it is conceivable to close the bypass section by, for example, reducing the opening amount of the flow rate regulating valve to zero, but if this is done, the power transmission path will be Immediately after the shutoff state is established, there is a risk that the amount of intake air will be insufficient and an engine stall will occur.

In view of the above, the present invention is such that the throttle valve disposed in the intake passage or the flow rate regulating valve disposed in the bypass section is opened in a predetermined manner even during deceleration, so that the intake air flow is reduced during deceleration. The intake air in the passageway between the supercharger and the throttle valve is pressurized by the supercharger, which can cause a situation where the feeling of deceleration is impaired or the engine speed suddenly increases. It is an object of the present invention to provide an intake air amount control device for a supercharged engine that prevents the intake air from being depleted.

(Means for Solving the Problem) In order to achieve the above-mentioned object, an intake air amount control device for a supercharged engine according to the present invention includes a supercharger disposed in an intake passage of an engine, and a supercharger disposed in an intake passage of an engine. In addition to the throttle valve disposed downstream of the supercharger, the flow rate control device controls the opening operation amount of the throttle valve or a flow rate regulating valve disposed in a bypass section for the throttle valve. The flow rate control means is configured to include:
When the engine is in a deceleration state, the greater the pressure in the intake passage between the supercharger and the throttle valve is than the atmospheric pressure, the less the opening amount of the throttle valve or flow regulating valve is controlled. shall be carried out.

(Function) In the intake air amount control device for a supercharged engine according to the present invention having the above-described configuration, the flow rate control means controls the flow rate of the throttle valve disposed in the intake passage or the bypass portion. When the engine is in a decelerating state, the valve-opening amount of the flow rate regulating valve is controlled so that it becomes smaller as the pressure in the portion of the intake passage between the supercharger and the throttle valve is greater than atmospheric pressure. be done.

By doing this, when the engine is in a deceleration state, even if the intake air in the portion of the intake passage between the supercharger and the throttle valve is pressurized by the supercharger and becomes higher than atmospheric pressure. This prevents the amount of intake air passing through the throttle valve or bypass section from increasing excessively, resulting in a good sense of deceleration and a sudden increase in engine speed when gear changes are performed. It is possible to prevent such things as

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows an example of an intake air amount control device for a supercharged engine according to the present invention, together with an engine to which the device is applied.

In FIG. 1, a piston 10 is inserted into an engine body E, and a combustion chamber 11 in which a spark plug 7 is installed is formed in the upper part of the piston 10.
An intake passage 12 and an exhaust passage 13 are connected via an intake valve 8 and an exhaust valve 9.

The intake passage 12 includes the intake passage 12 sequentially from the upstream side.
Air cleaner 14 for introducing intake air into the air flow meter 15 for detecting the amount of intake air. A turbo supercharger 20 that includes a turbine 16 disposed in the exhaust passage 13 and a compressor 17 that is driven by the turbine 16 and pressurizes the intake air introduced into the intake passage 12. Supercharger 2o
Intake pressure 21. cools the intake air pressurized by the compressor 17 at 21. Pressure sensor 22° Opens and closes in conjunction with the accelerator pedal, and opens and closes the combustion chamber 11.
Throttle 23. which adjusts the amount of intake air introduced into the engine. A throttle opening sensor 24 that detects the opening of the throttle valve 23. Surge tank 2 with relatively large volume
5, and a fuel injection valve 27 that injects fuel fed under pressure from the fuel supply system toward the intake port.

The fuel injection valve 27 is connected to a control unit 1 which will be described later.
By supplying the injection drive pulse signal Cp from 00, it is brought into an open state for a period corresponding to the pulse width of the injection drive pulse signal Cp, and fuel is pressure-regulated and pumped by a fuel supply system (not shown). The fuel is injected intermittently toward the intake port near the combustion chamber 11. And the combustion chamber 11
The air-fuel mixture introduced into the engine is ignited by the spark plug 7 to be combusted, and is discharged into the exhaust passage 13 as exhaust gas.

Further, the intake passage 12 is provided with a bypass portion 26 that communicates a portion between the intercooler 21 and the throttle valve 23 with the surge tank 25 . Bypass section 26
is provided with a flow rate adjustment valve 28, and this flow rate N adjustment valve 28 receives a valve drive pulse signal Cq by being supplied with a valve drive pulse signal Cq from the control unit 100.
It is kept open only for a period corresponding to the pulse width of q. Thereby, the amount of air passing through the bypass section 26 is adjusted.

The control unit 100 includes an air flow meter 1
5, a detection signal Sa corresponding to the intake air 1, a detection signal Sp obtained from the pressure sensor 22, corresponding to the pressure in the portion between the supercharger 2o and the throttle valve 23 in the intake passage 12, and Detection signal St corresponding to the opening degree of the throttle valve 23 obtained from the throttle opening degree sensor 24
is supplied, and a detection signal Sn corresponding to the engine rotation speed obtained from the rotation speed sensor 31 disposed in relation to the crank mechanism 30 in the engine body E and the engine cooling water temperature obtained from the water temperature sensor 32 are supplied. Detection signal Sw, clutch pedal, and shift lever according to
A detection signal Sχ obtained from various sensors arranged in connection with auxiliary machinery and the like and detecting the load imposed on the engine is also supplied. Furthermore, the control unit 10
0 is also supplied with a detection signal So corresponding to the atmospheric pressure from an atmospheric pressure sensor 33 provided therein.

Based on these Im detection signals, the control unit 100 controls the fuel injection amount in the fuel injection valve 27 and also controls the valve opening amount in the flow rate adjustment valve 28 to allow the intake air to pass through the bypass section 26. Control quantity.

When controlling the fuel injection m (7), the control unit 100 calculates the fuel injection amount based on the intake air amount and the engine rotation speed when the detection signals Sa and Sn are not present, respectively, and generates a pulse corresponding to the obtained fuel injection amount. Forms an injection drive pulse signal Cp having a width and sends it to the fuel injector 2.
Supply to 7.

On the other hand, when controlling the intake air amount by the control unit 1-100, the detection signal St detects that the throttle valve 23 is fully closed based on the actual throttle opening. For example, as shown in FIG.
is less than the value 'r1, the lower the cooling water temperature Tw is, the larger the value is, and when the cooling water temperature Tw is equal to or higher than the value T, it is set to a constant value G, and the second reference value G
o is the atmospheric pressure P at which the detection signal So is generated.

For example, as shown in FIG.
The larger the value, the smaller the value is set. Then, the set first reference value Gw and second reference value Go are added to set the basic control value CB.

Further, based on the detection signal Sx, a correction value GX is set depending on the state of the power transmission path from the engine to the wheels, the load imposed on the engine by auxiliary machinery, and the like.

Based on the detection signal Sn, the engine detects that the engine rotation speed N is a predetermined value N1, for example, 120 Orp.
When it is detected that the engine is in an idling state where the temperature is below m, a detection signal Sw is generated.A target idle speed No. A feedback correction value CF is set according to the difference from NO, and a control value G is set by adding the feedback correction CI'' to the basic control value CB and the correction value GX.Then, according to the set control value G The valve driving pulse signal cq is the flow rate adjustment fi'
-28.

As a result, the valve-opening amount of the flow rate regulating valve 28 is changed so that the engine speed N matches the target idle speed No, and feedback control of the intake air amount is performed.

Furthermore, when it is detected that the engine is in a deceleration state where the engine rotation speed N is greater than the value N, although the throttle valve 23 is in the fully closed state, the feedback correction value GF is set to zero, and , the basic control value GB obtained by adding the first reference value Gw and the second reference value GO.
is multiplied by the supercharging pressure correction coefficient II to set a new basic control value CB, and the control value G becomes the set basic control value G.
(2) The value is set to the sum of 3 and the correction value GX. In that case, the supercharging pressure correction coefficient F■ is determined by, for example, the bypass portion in the portion between the throttle valve 23 provided in the intake passage 12 and the intercooler 21 where the detection signal Sp occurs, as shown in FIG. When the pressure pp near where the second-flow side end of No. 26 is open is below atmospheric pressure or a value P slightly smaller than that, set to ■, for example.
When the value is relatively large, such as 22 or more, for example, 0.
5, and when taking a value between the value P1 and the value P2, the larger the pressure pp is, the smaller the value is set.

Therefore, when the engine is in a deceleration state, the pressure Pp
The larger the control value G is, the smaller the control value G is set, and a valve drive pulse signal Cq having a pulse width according to the set control value G is formed, which is supplied to the flow rate adjustment valve 28. When the engine is in a supercharged state in which intake air is pressurized by the operation of the supercharger 20, the flow rate adjustment valve 28 has a smaller opening operation amount than when it is in a non-supercharged state. It is said that

In this way, when the engine is in a deceleration state, the throttle value G is set based not only on the engine cooling water temperature and atmospheric pressure, but also on the pressure in the area between the throttle valve 23 and the supercharger 20 in the intake passage. By controlling the opening operation amount of the flow rate regulating valve 28 according to the control value G, when the engine is caused to shift from the deceleration state to the idling state, the engine speed N is set to the target idle speed NO.
In addition, when in the deceleration state, the amount of intake air passing through the bypass section 26 is prevented from increasing excessively, so that a good feeling of deceleration can be obtained, and the speed change Even when the power transmission path is cut off due to operation, etc., and the load imposed on the engine suddenly decreases, the engine speed N
It is possible to prevent a situation in which the amount increases rapidly.

Note that when the throttle valve 23 is not in the fully closed state, the control value G is set to a fixed value, and a valve drive pulse signal Cq is generated according to the set control value G, which is applied to the flow rate regulating valve 28. Supplied.

The control unit 100 that performs the above-described control is configured using, for example, a microcomputer, and an example of a program executed by the microcomputer to control the intake air amount in such a case is shown in the flowchart of FIG. Explain with reference to.

The program shown in the flowchart of FIG. 5 starts, for example, when the ignition switch is turned on, and after the start, the detection signals Sn and So are generated in the program 101.

Sp, St, Sw, and Sx are taken in, and in the subsequent decision 102, it is determined whether the throttle valve 23 is fully open based on the throttle opening since the detection signal St is not detected. Then, if it is determined that the throttle valve 23 is in the fully closed state, in process 103,
The first reference value Gw is set according to the cooling water temperature Tw of the engine at which the detection signal Sw occurs, and the detection signal S
.

A second reference value GO is set in accordance with the atmospheric pressure Po at which a storm occurs, and the process proceeds to Processed 04, where the basic control value CB is set by adding the first reference value Gw and the second reference value GO. do. Then, in process 105, the detection signal S
A correction value GX is set depending on the load etc. imposed on the engine when x occurs, and the process proceeds to decision 107.

In decision 107, the detection signal Sn indicates that the engine rotational speed N is a predetermined value N or less, for example, 12
It is determined whether or not the engine speed is 0Orpm or less, and if it is determined that the engine speed N is less than the value NI, the engine is in an idling state, so in process 109, the engine cooling water temperature Tw and the engine speed are adjusted. A target idle speed No. is set according to the load etc. to be applied, and in the subsequent process 110, the absolute value of the difference between the engine speed N and the target idle speed No. is calculated and set as ΔN, and in a decision 112, The difference ΔN is a predetermined value α
Determine whether the value is less than or equal to the value. If it is determined that the difference ΔN is not less than the value α, then in decision 114, it is determined whether the engine speed N is equal to or higher than the target idle speed No. If it is determined that the value is NO or more, in process 115, a predetermined value β is subtracted from the feedback correction value GF to set a new feedback correction value GF, and then the process proceeds to process 117. Further, if it is determined in decision 114 that the engine rotation speed N is less than the target idle rotation speed No, the process 11
In step 6, the value β is added to the feed bank correction value CF to set a new feedback correction value GF, and then the process proceeds to process 117.

In process 117, the control value G is set to 2G=GB+
In the subsequent process 118, a valve drive pulse signal Cq having a pulse width according to the control value G calculated in process 117 is formed and sent to the meteor adjustment valve on the second day.

On the other hand, in decision 107, the engine speed N
If it is determined that is larger than the value N, the engine is in a deceleration state, so in process 121 the feedback correction value CF is set to zero, and in the following process 12
2, a new basic control value CB is set by multiplying the basic control value CB by the supercharging pressure correction coefficient 11 set according to the pressure pp when the detection signal Sp is not detected, and the process proceeds to process 117. Execute the Ste Knob in the same way as above to return to the original position. In addition, Decision 10
2, if it is determined that the throttle valve 23 is not in the fully closed state, the control value G is set to a fixed value in process 123, and the process proceeds to process 118.
18 in the same manner as above and return to the original state.

(Effects of the Invention) As is clear from the above description, according to the intake air amount control device for a supercharged engine according to the present invention, a The valve opening operation amount of the regulating valve is controlled so that when the engine is in a decelerating state, the greater the pressure in the intake passage between the supercharger and the throttle valve, the smaller the amount.
As a result, the amount of intake air passing through the throttle valve or flow N adjustment valve is prevented from increasing excessively, and as a result, it is possible to obtain a good deceleration feeling, and it is possible to avoid excessive increase in the amount of intake air passing through the throttle valve or flow N adjustment valve. When the load imposed on the engine suddenly decreases, the engine speed can be prevented from increasing rapidly.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of the intake air amount control device for a supercharged engine according to the present invention, together with an engine to which it is applied, and FIGS. FIG. 5 is an example of a program executed by a microcomputer in the case where a microcomputer is used in the control unit provided in the example shown in FIG. It is a flowchart which shows. In the figure, 1 and 2 are intake passages, 13 are exhaust passages, 20 is a supercharger, 22 is a pressure sensor, 23 is a throttle valve, 26 is a bypass section, 28 is a meteor adjustment valve, and 100 is a control unit.

Claims (1)

[Scope of Claims] A supercharger disposed in an intake passage of an engine; a throttle valve disposed in a downstream portion of the intake passage from the supercharger; when the engine is in a deceleration state; The higher the pressure in the portion of the intake passage between the supercharger and the throttle valve is, the more the throttle valve or the flow rate regulating valve disposed in the bypass section for the throttle valve opens. An intake air amount control device for a supercharged engine, comprising: a flow rate control means for controlling the amount of air to be reduced;