JP3257852B2 - Control device for engine with mechanical supercharger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an engine with a mechanical supercharger, and more particularly to a control device for a supercharged engine having a bypass passage for bypassing the mechanical supercharger and a bypass air valve for opening and closing the bypass passage. The present invention relates to a control device for a mechanical supercharged engine.

[0002]

2. Description of the Related Art Some automobile engines are provided with a supercharger for increasing the amount of air charged into a combustion chamber. As this supercharger, a mechanical supercharger driven by an engine output is used. Machine (supercharger).

[0003] By the way, this type of turbocharger improves the engine output by increasing the intake charge as described above when the load is high, but in particular, when the load is low where no high output is required, the intake resistance and The disadvantage is that the fuel efficiency of the engine is degraded by reducing the mechanical loss of the engine.

Therefore, for example, Japanese Patent Application Laid-Open No. Hei 3-222819 is disclosed.
As disclosed in Japanese Patent Application Laid-Open Publication No. H11-209, a bypass passage that bypasses a turbocharger is provided in an intake passage, and a bypass air valve that opens and closes the bypass passage is provided. When the load is low, the valve is opened to open the bypass passage. Thus, the intake resistance or the drive loss of the supercharger is reduced.

[0005]

However, in the conventional apparatus, when the engine is decelerated when the throttle valve is fully closed, the bypass air valve is fully opened, so that the turbocharger compression loss is small and the engine brake feeling is reduced. There is a problem that is weakened.

On the other hand, the upstream side of the supercharger provided in the intake passage downstream of the throttle valve, which is fully closed when the engine is decelerated, has a negative pressure at the moment when the throttle valve is fully closed. If the air valve is kept closed, a large pressure difference (1000mmHg or more) will occur between the positive pressure and the downstream side of the turbocharger, which will cause the turbocharger to overheat and its reliability There is a problem that impairs.

Further, in order to reduce fuel consumption, a general electronically controlled fuel injection engine performs a fuel cut when the engine speed drops to about 1700 rpm (in the case of an AT car) at the time of engine deceleration.
When the fuel cut is reduced to such a degree, the fuel cut is stopped and the fuel injection is restored. However, when the fuel cut is restored, there is a problem that a torque shock occurs in the engine.

In view of the above circumstances, a first object of the present invention is to prevent overheating of a supercharger at the time of engine deceleration,
An object of the present invention is to provide a control device for an engine with a mechanical supercharger capable of obtaining an appropriate engine braking feeling while maintaining the reliability of the supercharger.

A second object of the present invention is to provide a control device for an engine with a mechanical supercharger capable of preventing occurrence of torque shock when returning from fuel cut.

[0010]

A control device for an engine with a mechanical supercharger according to the present invention includes a mechanical supercharger provided in an intake passage downstream of a throttle valve and driven by an engine output. A control device for an engine with a mechanical supercharger, comprising: a bypass passage for bypassing a mechanical supercharger; and a bypass air valve for opening and closing the bypass passage, wherein the control device relates to a temperature of the mechanical supercharger. First detecting means for detecting a parameter, second detecting means for detecting deceleration of the engine, and receiving the signals from the first and second detecting means to set the bypass air valve at an opening degree of the bypass air valve. so it becomes the minimum in the allowable temperature range of the mechanical supercharger, and a control means for controlling, on
The control means operates the above-mentioned by-pass for a predetermined period at the initial stage of engine deceleration.
After fully opening the pass air valve,
Is minimum within the allowable temperature range of the mechanical turbocharger.
It is characterized in that it is controlled so that:

The parameters relating to the temperature of the mechanical supercharger include not only the temperature of the mechanical supercharger itself, but also the discharge air intake temperature or the temperature between the upstream side and the downstream side of the mechanical supercharger. Pressure difference.

Also, the predetermined period during which the bypass air valve is fully opened is minimized within the allowable temperature range of the mechanical supercharger in accordance with the value of a parameter related to the temperature of the mechanical supercharger. Is set to

The control means controls the bypass air valve further in the closing direction simultaneously with the return from the fuel cut during engine deceleration. The opening degree of the bypass air valve, which is changed at the time of return from the fuel cut, is also minimized within the allowable temperature range of the mechanical supercharger according to the value of a parameter related to the temperature of the mechanical supercharger. Is set to be

Further , an engine with a mechanical supercharger according to the present invention.
The control device for the engine is located in the intake passage downstream of the throttle valve.
Mechanical supercharging provided by the engine output
Machine, a bypass passage that bypasses the mechanical supercharger,
A bypass air valve for opening and closing the bypass passage.
The control apparatus of the mechanical engine with a supercharger comprising Te, the d
Engine speed detecting means for detecting the engine speed, and an engine
Deceleration detecting means for detecting deceleration of the engine, and the rotational speed detecting means
And the number of revolutions of the engine
When the engine speed is below the first predetermined speed, the fuel cut
Start and the engine speed is lower than the first predetermined speed.
When the second predetermined number of revolutions
When the engine is decelerated and the air bypass
Vital to Suea valve is half opened state, the fuel cut
At the end of the operation, the bypass air valve is further closed
Control means for controlling
is there.

[0015]

According to the present invention, when the engine is decelerated, the opening of the bypass air valve is controlled to be minimized within the allowable temperature range of the mechanical supercharger.
An appropriate engine braking feeling can be obtained while maintaining the reliability of the turbocharger.

Further, at the initial stage of the engine deceleration, the bypass air valve is fully opened for a predetermined period, thereby preventing the supercharger from overheating due to the occurrence of the initial maximum pressure difference at the time of the engine deceleration.

Furthermore, since the bypass air valve is further controlled in the closing direction simultaneously with the return from the fuel cut, the feeling of engine braking is improved, and the torque shock due to the difference in the deceleration force due to the return from the fuel cut is increased. Can be reduced.

[0018]

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

In FIG. 1, a throttle valve 3, a mechanical supercharger 4, an intercooler 5, and a surge tank 6 are provided in an intake passage 2 of an engine 1 from an upstream side thereof. Downstream sides of a plurality of branch passages 7 whose sides are connected are connected to the intake ports of the respective cylinders of the engine 1.

The crankshaft 1 of the engine 1
When the supercharger 4 is driven via the belt 8 by a, the intake air which is sucked in from the upstream side of the intake passage 2 via the throttle valve 3 is pressurized, and then the intercooler 5, the surge tank The fuel is supplied to the combustion chamber 1b of each cylinder via the branch 6 and each branch passage 7.

The intake passage 2 is provided with a bypass passage 9 that branches off from the downstream side of the throttle valve 3 and joins the surge tank 6 to bypass the supercharger 4 and the intercooler 5. In addition, a bypass air valve 10 is provided on the bypass passage 9.

The bypass air valve 10 has inlets connected to upper and lower portions 9a and 9b of the bypass passage 9, respectively.
A housing 11 having a housing 11a and an outlet 11b, and a valve body 12 provided in the housing 11 to open and close the outlet 11b by coming into contact with and separating from the outlet 11b. the pressure in the plane in the bypass passage downstream section 9b facing the outlet 11b, i.e. the supercharging pressure P ₁ which is generated by the turbocharger 4 is applied in the opening direction of the valve element 12, also housing 1
Pressure on the upstream side of the bypass passage 9a on the surface facing the inside of 1;
That is, so as to act in the opening direction of the intake negative pressure P ₂ is also the valve element 12 that occurs downstream of the throttle valve 3 in the intake passage 2.

Further, an actuator 13 is attached to the housing 11 of the bypass air valve 10. The actuator 13 has a configuration in which the inside of a case 14 is partitioned into an atmosphere opening chamber 16 and a pressure chamber 17 by a diaphragm 15, and the diaphragm 15 is connected to a valve body 12 of a bypass air valve 10 via a rod 18. In the pressure chamber 17, a spring 19 for biasing the valve body 12 of the bypass air valve 10 in the closing direction via the diaphragm 15 and the rod 18 is provided.

Further, an intake negative pressure introducing passage 20 is provided between the downstream side of the throttle valve 3 and the pressure chamber 17 of the actuator 13.
Is provided in the intake negative pressure introduction passage 20.
A duty solenoid valve 22 whose opening is duty-controlled by 21 is interposed.

When the throttle valve 3 is fully closed while the vehicle is running, that is, when the solenoid valve 22 is fully opened during deceleration of the engine, the intake negative pressure P ₂ generated downstream of the throttle valve 3. Is introduced into the pressure chamber 17, and the intake negative pressure P ₂ in the pressure chamber 17 acts on the diaphragm 15 in a direction opposite to the urging force of the spring 19, and bypasses the urging force of the spring 19. When the valve body 12 of the air valve 10 is fully opened and the solenoid valve 22 is fully closed, the valve body 12
Is fully closed by the urging force of
Further, the opening of the valve body 12 of the bypass air valve 10 is changed according to the opening of the solenoid valve 22.

The controller 21 receives a signal from an idle switch 23 which is turned on when the throttle valve 3 is fully closed, a signal indicating an engine speed Ne from an engine speed sensor 24, and a signal from a vehicle speed sensor 25. A signal representing the vehicle speed VSP, a signal from a temperature sensor 26 for detecting the temperature of the supercharger 4, and a sensor 27 for detecting a gear engaged state of the transmission.
And a sensor for detecting that the clutch is engaged in a vehicle (MT vehicle) having a manual transmission
28, an opening sensor 29 for detecting the opening of the valve body 12 of the bypass air valve 10, and the like. Based on these input signals, the controller 21 determines a pulse width TI of a driving pulse for an injector (not shown) based on these input signals. To control the fuel injection amount, execute fuel cut when the engine is decelerated, and change the duty ratio of the control signal output to the duty solenoid valve 22 to change the valve element 12 of the bypass air valve 10. The opening degree is controlled.

In the present embodiment, the temperature of the supercharger 4 itself detected by the temperature sensor 26 is used as a parameter related to the temperature of the supercharger 4. Or the pressure difference between the upstream side and the downstream side of the supercharger 4 may be used.

FIG. 2 is a timing chart for explaining the operation of the present embodiment.

First, when the throttle valve 3 is fully closed at time t1 (the opening TVO of the throttle valve 3 is zero) while the vehicle is running, the engine is decelerated and the engine speed Ne decreases. Then, the engine speed Ne at the time t1 is immediately if preset fuel cut start rotational speed Ne ₂ or less, the fuel cut flag is set at the time when decreased to Ne ₂ if beyond Ne ₂ Fuel cut is started.

On the other hand, the bypass air valve (ABV) 10 is fully closed until time t1, but is half-opened from time t1. At this time, the opening degree A (for example, 50%) is set to be the minimum within the allowable temperature range of the turbocharger 4. However, when the temperature condition is severe such as in summer, a chain line in FIG. As described above, the opening degree is set to the opening degree A after being fully opened until the time point t2. Further, the full open period T of the bypass air valve 10 at this time is also set to be the minimum within the allowable temperature range of the supercharger 4.

Next, at time t3 when the engine rotational speed Ne has decreased to the rotation speed Ne ₁ to return from the fuel cut,
When the fuel cut flag is defeated to terminate the fuel cut, the opening of the bypass air valve 10 is further changed to the closing direction. The closing control of the bypass air valve 10 is for increasing the compression loss of the supercharger 4 to prevent the occurrence of torque shock due to the difference in deceleration force due to the return from the fuel cut. 10 degree of opening B (for example, 20%)
Is also set to a minimum within the allowable temperature range of the supercharger 4.

It should be noted that the switching of the opening degree constant of the bypass air valve 10 returns from the fuel cut to the rotation speed Ne _1.
In the case of this embodiment, there is a possibility that a torque shock occurs due to unmatching.
The opening degree constant of the bypass air valve 10 is switched depending on whether the fuel cut flag is standing or falling.

Next, decreases the engine speed Ne further, although at the time t4 is reached the idle speed Ne _0, in order to fully open the bypass air valve 10 in the idle speed Ne _0, the time t3 and the t4 During this time, the bypass air valve 10 is gradually opened. The reason why the bypass air valve 10 is fully opened at the idling rotational speed Ne ₀ is to reduce fuel consumption in an idling state and to prevent an increase in creep vehicle speed in a vehicle equipped with an automatic transmission (AT vehicle).

FIG. 3 shows a flowchart of a routine for controlling the opening of the bypass air valve 10 executed by the controller 21.

Steps S1 to S4 in FIG. 3 are steps for determining whether or not the control execution condition is satisfied. That is, in step S1, whether or not the idle switch 23 is ON, in step S2, whether or not the gear is engaged, in step S3, whether or not the vehicle speed VSP and the engine speed Ne are equal to or more than predetermined values, and in step S4. Then, it is determined whether or not the clutch is engaged. When the determination results in steps S1 to S4 are all "YES", the process proceeds to step S5 to read the gear position, and reads the engine speed Ne in the next step S6. , Step S
At 7, it is determined whether or not the pulse width of the injector drive pulse is zero.

When TI = 0 (during fuel cut) as shown in FIG.
A control map indicating the opening degree of the bypass air valve 10 at the time of ≠ 0 (fuel cut stop) is stored for each shift speed, and when the determination in step S7 is “YES”,
Proceeding to step S8, a map corresponding to the current gear position is selected, and the opening of the bypass air valve 10 corresponding to the engine speed Ne at that time is read.
At 9, the opening control of the bypass air valve 10 is performed so that the reading opening is obtained.

On the other hand, when the determination in step S7 is "NO", the process proceeds to step S10, in which a map corresponding to the current gear position is selected, and the engine speed N at that time is selected.
The opening degree of the bypass air valve 10 corresponding to e is read, and the opening degree control of the bypass air valve 10 is executed so that the reading opening degree is obtained in step S9.

[0038] In the map of FIG. 4, the fuel cut near the rotation speed Ne _1, the opening degree of the bypass air valve 10 during the fuel cut, and the opening degree of the bypass air valve 10 after the fuel cut is overlap However, this is because, as described above, the opening degree constant of the bypass air valve 10 is switched depending on whether the fuel cut flag is standing or falling.

In the map of FIG. 4, the values of the opening degrees A and B of the bypass air valve 10 shown in FIG. 2 are the parameter values 8 related to the temperature of the supercharger 4 (in this case, the temperature sensor 26 The correction is made according to the detected temperature of the supercharger 4 itself.

As is apparent from the above description, according to the present embodiment, by performing such opening control of the bypass air valve 10 at the time of engine deceleration, the reliability of the turbocharger 4 can be maintained. An appropriate engine braking feeling can be obtained, and torque shock due to a difference in deceleration force due to return from fuel cut can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the present invention.

FIG. 3 is a flowchart showing the control routine.

FIG. 4 is a diagram showing the control map;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine 2 Intake passage 3 Throttle valve 4 Mechanical supercharger 9 Bypass passage 10 Bypass air valve 13 Actuator 15 Diaphragm 19 Spring 20 Intake negative pressure introduction passage 21 Controller 22 Duty solenoid valve 23 Idle switch 24 Engine speed sensor 26 Temperature sensor

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02B 33/00 F02D 41/02 F02D 45/00 F02D 23/00

Claims (3)

(57) [Claims] 1. A mechanical supercharger provided in an intake passage downstream of a throttle valve and driven by an engine output, a bypass passage bypassing the mechanical supercharger, and a bypass opening and closing the bypass passage. A control device for an engine with a mechanical supercharger, comprising: an air valve; a first detecting means for detecting a parameter related to a temperature of the mechanical supercharger; and a second detecting means for detecting a deceleration of the engine. And the bypass air valve receiving the signal from the first and second detection means so that the opening degree of the bypass air valve is minimized within the allowable temperature range of the mechanical supercharger. Control means for controlling the control means , wherein the control means performs the above-described control for a predetermined period at the initial stage of engine deceleration.
After fully opening the bypass air valve,
The minimum opening of the valve within the allowable temperature range of the mechanical turbocharger.
A control device for an engine with a mechanical supercharger, characterized in that the control is performed as follows . 2. The control means controls the bypass air valve further in the closing direction simultaneously with the return from fuel cut during engine deceleration.
The control device for an engine with a mechanical supercharger according to claim 1 . 3. An intake passage downstream of a throttle valve.
Mechanical supercharger provided and driven by engine output
A bypass passage that bypasses the mechanical supercharger;
A bypass air valve that opens and closes the bypass passage
A control device for an engine with a mechanical supercharger , comprising:
Deceleration detecting means for detecting the deceleration of the engine,
Engine rotation in response to signals from gear and deceleration detection means
When the number is less than the first predetermined number of revolutions,
Start and the engine speed is equal to the first predetermined speed
When the engine speed falls below a second predetermined speed.
End the air cut, and stop the air
With the bypass air valve half-opened and the fuel
In addition閉方the above Baipasue Abarubu at the time of Rukatto end
And control means for controlling the
Control device for engine with mechanical supercharger.