JPH03194136A - Control device for engine with supercharger - Google Patents

Abstract

PURPOSE:To reduce switching shock by providing a control gain changing part for changing control gain to the small value on the basis of the accelerator manipulated variable detecting means at the switching time from the control performed by a throttle control means at the low load time to the control performed by a boost pressure regulating means at the high load time. CONSTITUTION:A control device for an engine with a supercharger is provided with a boost pressure regulating means 27 for regulating the exhaust air flow of an exhaust turbosupercharger 4 into a turbine. This regulating means 27 is controlled by a boost pressure control means 82 so as to obtain the target boost pressure corresponding to both detection values of an engine speed detecting means 61 and an accelerator manipulated variable detecting means 64 at the high load time. In this case, there is provided with a throttle valve driving means 60 for driving a throttle valve 16, and this driving means 60 is controlled by a throttle control means 81 so as to obtain the target opening corresponding to the above-mentioned both detection values at the low load time. The throttle control means 81 is further provided with a control gain changing part 83 for changing the gain of control to the small value on the basis of the accelerator manipulated variable at the high load time.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides an engine with an exhaust turbo supercharger which is controlled by a supercharger control means during high loads, in which the throttle valve is controlled by the engine rotational speed. The present invention relates to a control device for a vehicle equipped with a throttle control means that performs control based on the amount of accelerator operation and the amount of accelerator operation, and particularly relates to an improvement in the control of the throttle control means.

(Prior Art) Generally, in an engine with an exhaust turbo supercharger, as disclosed in Japanese Patent Publication No. 62-9723, for example, an engine rotation speed detection means for detecting the engine rotation speed;
an accelerator operation amount detection means for detecting an accelerator operation amount;
an exhaust turbo supercharger that supercharges the engine by pressurizing intake air using a turbine driven by exhaust gas; a supercharging pressure adjustment means that adjusts the flow rate of exhaust gas to the turbine of the exhaust turbo supercharger; and the engine. The boost pressure adjustment means is adjusted at high load (
For example, some systems are known that are equipped with boost pressure control means for controlling the boost pressure when the engine speed is high (for example, when the engine speed is high).

In this case, when the supercharging pressure control means starts to control the supercharger (supercharging pressure adjustment means) as the engine speed increases from a low load such as during normal driving (when the engine speed is low), , the supercharging pressure adjusting means is controlled to gradually close from the open state using a predetermined control gain based on the accelerator operating acceleration detected by the accelerator operating amount detecting means, so that the supercharging pressure gradually reaches the target supercharging pressure. I'm trying to get it close to.

Also, the amount of intake air pressurized by the exhaust turbo supercharger is
It is regulated by a mechanical type throttle valve that opens and closes in response to the amount of accelerator operation at a ratio of 1:1.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional system, supercharging occurs as the engine speed increases from low load times such as during normal driving, when controlling the supercharger by the supercharging pressure control means is not so necessary. When the pressure control means starts controlling the supercharger, the response of the engine suddenly improves.

This is because the response of the engine, which was slow to respond to the amount of accelerator operation by the driver in the low rotation region (low load region) and slow to increase the rotation speed, is due to the increase in boost pressure in the high rotation region (high load region). This is because the speed of response to the amount of accelerator operation by the driver is fast and the rotational speed increases rapidly, which improves the engine speed, but there is a drawback that the driver feels uncomfortable when the response of the engine suddenly improves.

Incidentally, the present invention includes a throttle control means for controlling the throttle valve driving means with a predetermined control gain so that the throttle valve has a target opening corresponding to both detection values detected by the engine rotation speed detection means and the accelerator operation amount detection means. There is an electric type throttle valve (Japanese Patent Laid-Open No. 61
(Refer to Publication No.-126346). According to this method, the throttle valve driving means is controlled so that the optimum target opening of the throttle valve is obtained according to the engine speed at that time while the accelerator operation amount remains constant without sequentially changing it. ing.

In this case, even if an electric type throttle valve is combined with an engine equipped with an exhaust turbo supercharger, the throttle valve by the throttle control means (throttle valve driving means)
Since the control is performed based on the accelerator operation amount from the accelerator operation amount detection means, it is undeniable that there is a difference in the response speed to the accelerator operation amount in the low load area and the high load area. There is nothing wrong with making people feel uncomfortable.

The present invention has been made in view of the above points, and its object is to provide a system in which an electric type throttle valve is combined with an exhaust turbo supercharger, in which the amount of accelerator operation in the low load region and the high load region is mutually controlled. This aims to eliminate the sense of discomfort given to the driver by changing the control gain of the throttle control means so that there is no difference in the response speed of the throttle control means.

In particular, by changing the control gain of the throttle control means when switching from a low load area to a high load area,
Another purpose is to eliminate the sense of discomfort that the driver feels when switching.

Another object of the present invention is to change the control gain of the throttle control means even when switching from a high load area to a low load area, thereby eliminating the sense of discomfort given to the driver at the time of switching.

(Means for Solving the Problem) In order to achieve the above object, the solving means taken by the invention according to claim (1) is as shown in FIG. 1, an accelerator operation amount detection means 64 that detects the accelerator operation amount, and an exhaust turbo supercharger that supercharges the engine 1 by pressurizing intake air by a turbine driven by exhaust gas. A charger 4 and a supercharging pressure adjusting means 2 that adjusts the flow rate of exhaust gas to the turbine of the exhaust turbo supercharger 4
7, and supercharging that controls the boost pressure adjusting means 27 at high load so that the target boost pressure corresponds to both detection values detected by the engine rotation speed detection means 61 and the accelerator operation amount detection means 64. It is assumed that the supercharged engine 1 is equipped with a pressure control means 82. The throttle valve driving means 60 drives the throttle valve 16, and the throttle valve driving means adjusts the opening degree to a target opening corresponding to both the detection values detected by the engine rotation speed detection means 61 and the accelerator operation amount detection means 64. 60 at low load. Further, the throttle control means 81 is provided with a control gain changing section 83 that changes the gain of the control based on the accelerator operation amount detection means 64 to a small value when the load is high.

In addition, the solution taken by the invention according to claim (2) is that when the throttle control means 81 is switched from the control by the throttle control means 81 at low load to the control by the supercharging pressure adjustment means 82 at high load, Control gain changing unit 8 that changes the control gain based on the accelerator operation amount detection means 64 to a smaller value
3 is provided.

Furthermore, the solution taken by the invention according to claim (3) is:
The throttle control means 81 includes control by the supercharging pressure adjustment means 82 at high loads to throttle control means 81 at low loads.
This configuration is provided with a control gain changing section 83 that greatly changes the gain of the control based on the accelerator operation amount detection means 64 when switching to the control based on the accelerator operation amount detection means 64.

(Function) With the above configuration, in the invention according to claim (1), the response of the engine, which has a slow response speed to the driver's accelerator operation amount and poor extension of the rotation speed in the low load region (low rotation region), is improved. This problem can be overcome by using an electric type throttle that can obtain the optimum target opening degree of the throttle valve according to the engine speed at that time.

In that case, the control gain of the throttle control means 81 based on the accelerator operation amount detection means 64 is changed to a smaller value by the control gain changing section 83 during high loads, so that the throttle valve 16 is adjusted to a smaller value than the throttle valve 16 in response to the driver's accelerator operation amount during high loads. The speed of opening/closing operation by the valve driving means 60 is slower than the opening/closing speed of the throttle valve 16 by the throttle valve driving means 60 relative to the amount of accelerator operation by the driver at low load, and the speed of the opening/closing operation of the throttle valve 16 by the throttle valve driving means 60 is lower than the speed of the opening/closing operation of the throttle valve 16 by the throttle valve driving means 60 in a high load region (high rotation region). As the boost pressure increases, the response speed to the amount of accelerator operation by the driver is fast, and a sudden increase in engine speed is suppressed. Therefore, there is no difference in the response speed to the accelerator operation amount in the low load region and the high load region, and the driver does not feel uncomfortable.

Further, in the invention according to claim (2), the throttle control means is based on the accelerator operation amount detection means 64 when switching from the control by the throttle control means 81 at low load to the control by the supercharging pressure adjustment means 82 at high load. Since the control gain of 81 is changed to a smaller value by the control gain changing unit 8B, the opening/closing operation speed of the throttle valve 16 by the throttle valve driving means 60 in response to the amount of accelerator operation by the driver in the high load area is changed to be smaller than that of the driver in the low load area. Throttle valve driving means 60 for throttle valve 16 in response to accelerator operation amount
This suppresses the sudden increase in the response speed to the driver's accelerator operation amount due to the rise in boost pressure when switching from a low load area to a high load area. , the driver will not feel any discomfort.

Furthermore, in the invention according to claim (3), the throttle control based on the accelerator operation amount detection means 64 is performed when switching from the control by the supercharging pressure adjusting means 82 at high loads to the control by the throttle control means 8 at low loads. Since the control gain of the control means 8] is largely changed by the control gain changing section 83, the opening/closing operation speed of the throttle valve 16 by the throttle valve drive means 60 in response to the amount of accelerator operation by the driver in the high load area is changed from that in the low load area. This reduces the sudden slowdown in the opening/closing speed of the throttle valve 16 by the throttle valve driving means 60 in response to the amount of accelerator operation by the driver, and prevents overloading when switching from a high load area to a low load area. This suppresses the sudden slowdown in response speed to the amount of accelerator operation by the driver due to a drop in supply pressure.
The driver will not feel any discomfort.

(First Embodiment) Hereinafter, an embodiment of the present invention will be described based on the drawings from FIG. 2 onwards.

Fig. 2 shows a 20-type turbocharger (=J rotary piston engine) equipped with a control device for a supercharged engine according to an embodiment of the present invention. The engine is of the so-called sequential turbo type.In Fig. 2, reference numeral 1 denotes an engine, and exhaust passages 2 and 3 for each cylinder are provided independently of each other.

A turbine 5 of a primary turbocharger 4 is disposed in one of these two exhaust passages 2 and 3, and a turbine 7 of a secondary turbocharger 6 is disposed in the other. That is, in this engine 1, the exhaust passages 2 and 3 of each cylinder are independently guided to the turbines 5 and 7 of both the primary and secondary exhaust turbo superchargers 4 and 6, so that the exhaust passages 2 and 3 of each cylinder are independently guided to the turbines 5 and 7 of both the primary and secondary exhaust turbo superchargers 4, 6. 6, the exhaust dynamic pressure is effectively applied to both turbines 5 and 7 in the region where supercharging is performed, thereby improving supercharging efficiency. The two exhaust passages 2 and 3 merge downstream of both turbines 5 and 7 to form one exhaust passage 24.

Further, the intake passage 9a is divided into two downstream of an air cleaner (not shown), and the blower 11 of the primary turbo supercharger 4 is located in the middle of the first branch passage 102.
Further, a blower 13 of the secondary turbo supercharger 6 is disposed in the middle of the second branch passage 12. These branch passages 10.12 are formed so as to face each other at the branch part and extend substantially straight on both sides. Moreover, the two branch passages 10, 12 merge again downstream of each blower 11.13.

Then, an intercooler 14 is disposed in the intake passage 9b, which has become one again, a surge tank 15 is located seven places downstream, and a throttle valve 16 is located between the intercooler 14 and the surge tank 15. It is arranged. Further, the downstream end of the intake passage 9b branches into two independent intake passages 17 and 18 corresponding to each cylinder of the engine 1, and is connected to each intake boat (not shown). Each of these independent intake passages 17 and 18 has a fuel injection valve 19°2.
0 is placed.

An air flow meter 21 is provided upstream of the intake passage 9a to detect the amount of intake air, and is located upstream of the branch of the first and second branch passages 10.12.

The two exhaust passages 2 and 3 are communicated with each other by a relatively small diameter communication passage 22 upstream of both the primary and secondary turbochargers 4 and 6. In the exhaust passage 3 in which the secondary turbine 7 is disposed, an exhaust cut valve 23 is provided immediately downstream of the opening position of the communication passage 22. The exhaust cut valve 23 is of a so-called normally closed type. That is, a diaphragm type actuator 31 is linked to this exhaust cut valve 23 . A spring 31a is provided within the actuator 31 to always bias the exhaust cut valve 23 in the closing direction. Therefore, when the engine is not operating, the exhaust cut valve 23 is closed by the biasing force of the spring 31a because the actuator 31 is not operating.On the other hand, when the engine is operating and the actuator 31 is turned on, it receives the operating force of the actuator 31. Spring 31. The exhaust gas cut valve 23 is rotated clockwise in FIG. 1 to open against the biasing force of a and the exhaust dynamic pressure on the upstream side of the exhaust gas cut valve 23.

Further, a waste gate passage 25 is formed which communicates with a combined exhaust passage 24 downstream of the turbines 5 and 7, and a waste gate valve 27 (supercharging pressure adjustment means) are provided.

An exhaust leakage passage 28 is provided that communicates the wastegate valve second flow portion of the wastegate passage 25 with the downstream side of the exhaust cut valve of the exhaust passage 3 connected to the secondary turbine 7. The exhaust leak passage 28 includes
An exhaust leak valve 30 is provided which is linked to the diaphragm actuator 29.

On the other hand, an intake cut valve 32 is disposed downstream of the blower 13 in the branch passage 12 in which the blower 13 of the secondary turbocharger 6 is disposed. This intake cut valve 32 is constituted by a butterfly valve, and is also linked to a diaphragm type actuator 33. In addition, a relief passage 34 is provided in the branch passage 12 on the secondary side so as to bypass the blower 13.
A is formed in the relief passage 34, and a diaphragm type secondary intake relief valve 35a is disposed in the relief passage 34.

On the other hand, a relief passage 34b is formed in the branch passage 0 where the blower 11 of the primary turbocharger 4 is disposed so as to bypass the blower 11.
A primary intake relief valve 35b composed of a butterfly valve is disposed at b.

The pressure chamber of the actuator 29 that operates the exhaust leak valve 30 is connected via a conduit 36 to the blower 11 of the branch passage 10 in which the blower 11 of the primary turbocharger 4 is disposed.
It is communicated downstream (upstream of the relief passage 34b). When the pressure on the downstream side of the blower 11 exceeds a predetermined value, the actuator 29 is activated and the exhaust leak valve 30 is activated.
opens, whereby a small amount of exhaust gas flows into the exhaust leakage passage 28 and is supplied to the secondary turbine 7 when the exhaust cut valve 23 is closed. The secondary turbo supercharger 6 starts rotating before the exhaust cut valve 23 opens.

The pressure chamber of the actuator 33 that operates the intake cut valve 32 is connected to an electromagnetic solenoid type three-way valve 38 via a conduit 37.
connected to the output port of the

Further, the actuator 31 that operates the exhaust cut valve 23 is a differential pressure type actuator that is operated by a difference in pressure acting on two pressure chambers, and one pressure chamber is connected to an electromagnetic solenoid type actuator via a conduit 39a. is connected to the output port of another three-way valve 40a, and the other spring 3
1. The pressure chamber a is connected to the output port of another electromagnetic solenoid type three-way valve 40b through a conduit 39b. Further, a pressure chamber of an actuator 41a that operates the intake relief valve 35a is connected to an output port of another electromagnetic solenoid type three-way valve 43a through a conduit 42a. The secondary intake relief valve 35a keeps the relief passage 34a open until a predetermined time before the exhaust cut valve 23 and the intake cut valve 32 open, as will be described later. As a result, when the secondary turbo supercharger 6 is pre-rotated by the exhaust gas flowing through the exhaust leakage passage 28, the supercharging pressure P1 of the primary turbo supercharger 4 is reduced to a predetermined value or less, and the upstream side of the intake cut valve 32 is This prevents the pressure from rising and entering the surging region.

On the other hand, the pressure chamber of the actuator 41b that operates the primary intake relief valve 35b is connected to the output port of another electromagnetic solenoid type three-way valve 43b through a conduit 42b. The primary intake relief valve 35b is configured to adjust the amount of intake air pressurized by the blower 11 of the primary turbo supercharger 4 to be released.

The actuator 26 for operating the wastegate valve 27 is connected by a conduit 44 to the output port of another three-way valve 45 of the electromagnetic solenoid type.

Further, 55 is a battery, and 56 is an ignition switch provided on a harness that connects the battery 55 and the electrical system of the engine 1. When the ignition switch 56 is turned on, the current of the battery 55 is transferred to the engine 1. is supplied to the electrical system, and the engine 1 is turned on by turning on the starter (not shown).
starts. Also, turn off the ignition switch 56.
When F is activated, current from the battery 55 is no longer supplied to the electrical system of the engine 1, and the engine 1 is stopped.

And the above six electromagnetic solenoid type three-way valves 38.40
a, 40b, 43a, 43b, 45 and the two fuel injection valves 19, 20 are controlled by a control unit 46 configured using a microcomputer. Further, the throttle valve 16 is driven by a mechanical type actuator 60 (throttle valve driving means), and this actuator 60 is controlled by the control unit 46. The control unit 46 includes an output signal of an engine rotation speed sensor 61 (engine rotation speed detection means), a throttle valve opening sensor 62
, the output signal of the accelerator operation amount sensor 64 (accelerator operation amount detection means) that detects the operation amount of the accelerator pedal 63, the output signal of the aflow meter 21, the signal of the ignition switch 56 (whether it is energized or not). In addition to the output signal of the gear position from the transmission (not shown), the output signal from the vehicle speed sensor (not shown), the manifold pressure P1 downstream of the primary side blower 11, the opening degree of the waste gate passage 25, atmospheric pressure, The intake temperature etc. are controlled manually.

One input port of the electromagnetic solenoid type three-way valve 38 for controlling the intake cut valve 32 is connected to a negative pressure tank 48 via a conduit 47, and the other input port is connected to a differential pressure detection valve (described later) via a conduit 49. 50 output port door 0. Intake negative pressure downstream of the throat I/L valve 16 is introduced into the negative pressure tank 48 via a check valve 51.

Further, one input port of the three-way valve 40a for controlling the exhaust cut valve 23 is open to the atmosphere, and the other input port is a conduit connected to the downstream side of the blower of the primary supercharger 4 via a conduit 57. 36. and,
Similarly, one input port of the three-way valve 40b for controlling the exhaust cut valve is open to the atmosphere, and the other input port is connected to a conduit 47 connected to a negative pressure tank 48 via a conduit 52. has been done. Therefore, the actuator 31 that operates the exhaust cut valve 23 operates based on the differential pressure between the supercharging pressure of the intake air downstream of the primary side blower guided through the conduit 57 and the intake negative pressure guided through the conduit 52 and the conduit 47. It is operated by.

On the other hand, one input port of the three-way valve 43a for controlling the secondary intake relief valve 35a is connected to the negative pressure tank 48, and the other input port is open to the atmosphere. On the other hand, a three-way valve 43 for controlling the primary intake relief valve 35b
One input port of b is open to the atmosphere, and the other input port is connected to the primary side blower 1 through a conduit 54a.
It is connected to the conduit 36 that communicates with the first downstream side. Further, one port of the three-way valve 45 for controlling the six est gate valve 27 is open to the atmosphere, and the other input port is connected to the conduit 36 communicating with the downstream side of the primary side blower 11 through a conduit 54b. ing.

2] When the three-way valve 38 is ON, the differential pressure detection valve 50 connects the conduit 37 connected to the pressure chamber of the actuator 33 for operating the intake cut valve 32 to the output port of the differential pressure detection valve 50;
In the state in which the intake cut valve 32 is connected to the conduit 49, the pressure upstream of the intake cut valve 32, that is, the boost pressure P2 on the secondary side approaches the boost pressure P1 on the primary side, and the differential pressure PI-P2
disappears and the differential pressure P2-Pi becomes larger than a predetermined value, the atmosphere is introduced into the actuator 33 and the intake cut valve 32 is opened. Also, the three-way valve 38 is OFF.
When the conduit 37 on the actuator 33 side is connected to the conduit 47 connected to the negative pressure tank 48, negative pressure is supplied to the actuator 33 and the intake cut valve 32 is closed.

On the other hand, when the two three-way valves 40a and 40b for controlling the exhaust cut valve 23 are both OFF, the conduits 39a and 39b are opened to the atmosphere.
is closed by the biasing force of the spring 31a of the actuator 31.

On the other hand, when both the three-way valves 40a and 40b are turned on, the primary-side supercharging pressure P1 is introduced into one pressure chamber of the actuator 31 via the conduit 39a, and the pressure at which the other spring 31a is arranged is introduced. Negative pressure is generated in the chamber via the conduit 39b, and the actuator 31 receiving this relative pressure overcomes the high back pressure (exhaust dynamic pressure) acting on the exhaust upstream side of the exhaust cut valve 23, and The cut valve 23 opens quickly, and the secondary turbo supercharger 6 performs supercharging.

The secondary intake relief valve 35a is operated by an actuator 41a for operating the secondary intake relief valve 35a when the three-way valve 43a for controlling the secondary intake relief valve 35a is OFF.
When the conduit 42a connected to the pressure chamber of the actuator 41 is connected to the negative pressure tank 48 side, it opens as negative pressure is supplied to the actuator 41a, and when the three-way valve 43 is turned on, the conduit 42a connected to the pressure chamber of the actuator 41 opens. Opening the conduit 42 to the atmosphere closes it. On the other hand, when the three-way valve 43b for controlling the primary intake relief valve 35b is ON, the actuator 413b for operating the primary intake relief valve 35b communicates with the downstream side of the primary side blower 11 via the conduits 54a and 36. 43b
is released to the atmosphere when is OFF.

In addition, an actuator 26 for operating the waste gate valve 27
When the three-way valve 45 for controlling the waste gate valve 27 is ON, the primary side blower 11 is
It communicates downstream, and is released to the atmosphere when the three-way valve 45 is OFF.

In this embodiment, in order to prevent backflow of intake air to the secondary blower when the exhaust cut valve 23 closes and the intake cut valve 32 remains open during transition from a high load region to a low load region, in this region, The intake cut valve 32 is forcibly closed after a predetermined period of time (for example, 2 seconds) has elapsed starting from the time when the exhaust cut valve 23 is closed.

Next, switching by the control unit 46 between throttle control in a low load area such as during low rotation and supercharging pressure control in a high load area such as during high rotation will be explained based on the control flow shown in FIG.

FIG. 3 shows a flowchart for carrying out the above-described control.

First, in step sA of FIG. 3, the system is initialized. Then, in step SS,
During normal driving, the driver depresses the accelerator pedal 63, that is, the accelerator operation amount sensor 64 reads the accelerator operation amount α, the engine rotation speed sensor 61 reads the engine rotation speed ESP, and the transmission gear position (1 , 2, 3), reading the vehicle speed by the vehicle speed sensor, and reading the atmospheric pressure PA.
The intake air temperature TA is read.

Then, in step SC, the target manifold pressure po downstream of the primary side blower 11 with respect to the accelerator operation amount α is determined from the characteristics of each transmission gear position using the target manifold pressure graph shown in FIG. Next, in step SD, considering the engine speed ESP, atmospheric pressure PA, and intake air temperature TA read in step SB, a target manifold pressure P that meets these 5 conditions is calculated as P - P.
□ x KESP x I (PAx KTA (
K is a coefficient).

Thereafter, in step SE, based on the target manifold pressure P calculated in step SD and the engine speed read in step Ss, the current control area is changed to the throttle control area according to the control switching map shown in FIG. It is determined whether the low load area belongs to the boost pressure control area or the high load area belongs to the boost pressure control area.

Next, in step SF, it is determined whether or not the determination in step SE belongs to the low load region (throttle control region), and in the case of YES that it belongs to the high load region (throttle control region), step SG is performed. Then, the actuator 26 for operating the wastegate valve 27 sets the wastegate valve 27 to the fully open position to fully open the wastegate passage 25. Then, in step SH, throttle control is performed to control the throttle valve 166 by the actuator 60 for driving the throttle valve 166 so that the manifold pressure P1 downstream of the primary side blower 11 becomes the target manifold pressure P.

On the other hand, if the determination in step SF is NO that the low load area is not present, it is determined in step Sl whether or not it has been within 11 seconds since switching from the low load area to the high load area. 11 after switching to high load area
If YES within seconds, the process proceeds to step SG. On the other hand, if the determination in step S1 is No, which means that t1 seconds or more have passed since the switch from the low load area to the high load area, the throttle valve 16 is adjusted at a ratio of 1:1 to the accelerator operation amount in step SJ. The throttle valve 16 is controlled by an actuator 60 for driving the throttle valve 16 so that it is opened and closed in response. Then, in step StC, the wastegate valve 27 is set so that the manifold pressure P1 downstream of the primary side blower 11 becomes the target manifold pressure P.
The wastegate valve 27 is operated by the operating actuator 26.
Performs supercharging pressure control to control

Therefore, in step SH of the above flow, the throttle valve 16 is adjusted such that the manifold pressure P1 of the primary side blower 111 becomes the target manifold pressure P.
A throttle control means 81 is configured to control the throttle valve 16 by an actuator 60 for driving the throttle valve 16. Further, in step SK, the actuator 2 for operating the wastegate valve 27 is set so that the manifold pressure P1 downstream of the primary side blower 11 becomes the target manifold pressure P.
6 constitutes a supercharging pressure control means 82 that controls the waste gate valve 27.

Next, the throttle control in the low load region in step SH of the above flow will be explained with reference to the routine shown in FIG. 6. First, in step SHI, the target manifold pressure P is calculated from the target throttle opening map shown in FIG. The target throttle opening degree β of the throttle valve 16 is determined from the characteristics of the engine speed. Next, in step SH2, the control gain of the actuator 60 for driving the throttle valve 16 is changed to a small value to perform "smoothing" processing to 8 to moderate the opening/closing operation speed of the throttle valve 16. so that becomes the target throttle opening β.

The actuator 60 for driving the throttle valve 16 is slowly controlled by the control gain of the throttle control means 8 which has been changed to a small value.

Therefore, step 5)-12 of the above subroutine constitutes a control gain changing section 83 that changes the control gain of the actuator 60 for driving the throttle valve 16 to a small value.

Further, the boost pressure control in the high load region in step SK of the above flow will be explained with reference to the subroutine shown in FIG. 8. First, in step SK1, the target manifold pressure is determined from the target throttle opening map shown in FIG. The target opening degree γ of the waste gate passage 25 with respect to P is determined from the characteristics of the engine speed. Then step SK
2, the wastegate valve 27 is opened so that the wastegate passage 25 reaches the target opening degree γ.
It is controlled by an actuator 26 for operation.

Therefore, in the above embodiment, the response of the engine, which had a slow response speed and poor rotational speed extension to the amount of accelerator operation by the driver in the low load region (throttle control region) such as at low engine speeds, is The optimum target throttle opening β of the throttle valve 16 according to the number of throttle valves 16 is determined by the actuator 60 for driving the throttle valve 16.
It is obtained by

This will be overcome by an electric type throttle.

In that case, the control gain of the throttle control means 81 based on the accelerator operation amount sensor 64 is changed to a smaller value by the control gain changing unit 83 during high loads, so that the throttle valve 16 is adjusted to a smaller value according to the driver's accelerator operation amount during high loads. The speed of opening/closing operation by the actuator 60 for driving the throttle valve 16 becomes gentle (slow) compared to the speed of opening/closing operation by the actuator 60 for driving the throttle valve 16 in response to the driver's accelerator operation amount at low load. In a high load region, as the boost pressure increases, the response speed to the accelerator operation amount by the driver is fast, and a sudden increase in engine speed is suppressed. Therefore, the difference in response speed to the amount of accelerator operation in the low load region and the high load region is alleviated, and it is possible to prevent the driver from feeling uncomfortable.

It should be noted that the present invention is not limited to the above embodiments, but includes various other modifications.

For example, in the above embodiment, the engine is applied to a sequential turbo type engine with an exhaust turbo supercharger, but as shown in Fig. 10, it is applied to a single turbo type engine with an exhaust turbo supercharger. Of course you can do that. In the figures, the same parts as in the above embodiment are denoted by the same reference numerals, and detailed explanation thereof will be omitted. and,
The exhaust turbo supercharger is given the same reference numeral as that of the primary side exhaust turbo supercharger.

(Second Embodiment) FIGS. 11 to 14 show a second embodiment of the present invention,
In this second embodiment, the gentle control of the actuator 60 for driving the throttle valve 16 by the throttle control means 8 is gradually made gentler from the time of switching between the control by the throttle control means 811 and the control by the boost pressure control means 82. It is something to do. Note that the same parts as in the above embodiment are given the same reference numerals, and detailed explanation thereof will be omitted.

That is, step S of the subroutine of the first embodiment
The slow control of the actuator 60 for driving the throttle valve 16 in H2 will be explained with reference to the subroutine shown in FIG. The throttle control means 81 controls the waste gate valve 27 so that the waste gate passage 25 is opened at the target opening γ by the actuator 26 for operating the waste gate valve 27.
The control is switched to that by the supercharging pressure control means 82, which had been controlling so that t is within t1 seconds. If the determination in step S2A is No that t1 seconds or more have passed since the control by the throttle control means 81 was switched to the control by the supercharging pressure control means 82, step S2A
At B2, the waste gate valve 27 is connected to the waste gate valve 27.
The wastegate passage 2 is opened by the operating actuator 26.
The throttle valve 16 is controlled by the actuator 60 for driving the throat I/le valve 16 so that the throttle valve 16 becomes the target throttle opening β instead of the control by the supercharging pressure control means 82 that controlled the throttle valve 16 so that the throttle opening 5 becomes the target opening γ. The controller then switches to the control by the throttle control means 81, and determines whether or not it is within t1 seconds. If the determination in step 82B is YES within t1 seconds after switching from the control by the throttle control means 8 to the control by the supercharging pressure control means 82, the control gain of the throttle control means 81 is switched in step S2C. The actuator 6 for driving the throttle valve 16 is gradually changed to a smaller value during the time t1 seconds immediately after the
The "smoothing coefficient D" which causes the throttle valve 16 to gradually approach the target throttle opening degree β by 0 is set so as to gradually increase during the time t1 seconds in accordance with the characteristics shown in FIG. 12, and the process proceeds to step S2D. .

Then, in step S2D, the current target throttle opening degree βn after the time t1 seconds of the throttle valve 16 by the throttle control means 81, which has been smoothed by the "smoothing coefficient 3 D", is set as βn ← (1-D ) β
i +DX β interest rate (however, Q<D<1) (βn-1; previous target throttle opening) is calculated and output as a command signal to the throttle control means 81, and step 5t- of the first embodiment is performed. Proceed to step 13. In this case, as shown in FIG. 13, the smaller the smoothing coefficient is, the shorter the time it takes for the throttle valve 16 to approach the target throttle opening βn; The time approaching degree βn is delayed.

On the other hand, if the determination in step SEA is YES within t1 seconds after the control by the throttle control means 81 is switched to the control by the supercharging pressure control means 82, the control gain of the throttle control means 81 is changed in step SEE. The "smoothing coefficient D" is gradually changed greatly during the time t1 seconds immediately after switching, so that the actuator 60 for driving the throttle valve 16 quickly moves the throttle valve 16 closer to the target throttle opening degree β. It is set so that it gradually decreases during time t1 seconds in accordance with the characteristics shown in FIG. 14, and the process proceeds to step SAD. On the other hand, if the determination in step 828 is NO that t1 seconds or more have passed since the control was switched from the control by the throttle control means 8 to the control by the boost pressure control means 82, then in step 82F, the control by the throttle control means 81 is “Annealing coefficient D” without changing the control gain
'' is set to 0, and the process proceeds to step S2D.

In this case, the throttle control means 81 based on the accelerator operation amount sensor 64 changes from the control in the low load region by the throttle control means 81 at low load to the control in the high load region by the boost pressure adjustment means 82 at high load. The control gain is changed to a smaller value by the control gain changing unit 83, and the throttle valve 16 is changed to the throttle valve 16 based on the "smoothing coefficient D".
The drive actuator 60 gradually approaches the target throttle opening β. For this reason, the opening/closing operation speed of the throttle valve 16 in response to the driver's accelerator operation amount in the high load area 5 is slower than the opening/closing operation speed in the low load area, and when switching from the low load area to the high load area, The response speed of the actuator 60 for driving the throttle valve 16 to the driver's accelerator operation amount is suppressed from suddenly increasing as the boost pressure increases,
It is possible to eliminate the discomfort that the driver feels when switching.

On the other hand, the control gain of the throttle control means 81 based on the accelerator operation amount sensor 64 is changed by the control gain changing section 83 when switching from the control by the boost pressure adjustment means 82 under high load to the control by the throttle control means 81 under low load. This is greatly changed, and the actuator 60 for driving the throttle valve 16 based on the "smoothing coefficient D" quickly brings the throttle valve 16 close to the target throttle opening degree β. Therefore, the opening/closing speed of the throttle valve 16 in response to the amount of accelerator operation by the driver in the high load region is prevented from suddenly becoming slower than the opening/closing speed in the low load region. to 6. At the time of switching to a low load region, the response speed of the actuator 60 for driving the throttle valve 16 to the amount of accelerator operation by the driver is suppressed from suddenly slowing down due to a decrease in boost pressure, It can eliminate the discomfort caused by

(Effects of the Invention) As described above, according to the control device for a supercharged engine according to claim (1), the control gain based on the accelerator operation amount detection means is changed to a small value in the throttle control means when the load is high. Since the control gain changing section is provided, the opening/closing speed of the throttle valve by the throttle valve driving means in response to the driver's accelerator operation amount under high load is slower than the opening/closing speed of the throttle valve under low load. There is no difference in the response speed to the amount of accelerator operation between the low load region and the high load region, and the sense of discomfort given to the driver can be eliminated.

Further, according to the control device for a supercharged engine according to claim (2), the throttle control means changes from control by the throttle control means at low loads to control by the supercharging pressure adjusting means at high loads. A control gain changing section is provided to reduce the control gain based on the accelerator operation amount detection means at the time of switching, so that when switching from a low load area to a high load area, the amount of accelerator operation by the driver changes as the boost pressure increases. By suppressing the sudden increase in response speed,
It is possible to eliminate the discomfort that the driver feels when switching.

Furthermore, according to the control device for a supercharged engine according to claim (3), the throttle control means is configured to switch from control by the supercharging pressure adjusting means at high loads to control by the throttle control means at low loads. Since a control gain changing section is provided that greatly changes the control gain based on the accelerator operation amount detection means, the response to the driver's accelerator operation amount as the boost pressure decreases when switching from a high load area to a low load area is provided. It is possible to prevent the speed from suddenly decreasing, thereby eliminating the sense of discomfort given to the driver when switching.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 to 9 show a first embodiment of the present invention, and FIG. 2 is an overall configuration diagram of a supercharged engine;
Figure 3 is a flowchart showing switching between throttle control and boost pressure control, Figure 4 is a target manifold pressure map that determines the target manifold pressure for the accelerator operation amount from the gear shift position, and Figure 5 is for the engine rotation speed. Control switching map diagram that divides the low load area and high load area based on target manifold pressure, No. 6
The figure is a subroutine diagram for throttle control, Figure 7 is a target throttle opening map diagram that determines the target throttle opening for target manifold pressure from the engine speed, Figure 8 is a subroutine diagram for boost pressure control, and Figure 9 is a target throttle opening map. FIG. 3 is a map diagram of a target throttle opening degree in which the target bypass passage opening degree with respect to the manifold pressure is determined from the engine rotation speed. Further, FIG. 10 is a diagram corresponding to FIG. 2 showing a modification of the above embodiment. 11 to 14 show a second embodiment of the present invention, FIG. 11 is a subroutine diagram showing throttle valve opening control by round setting, and FIG. Figure 13 is a characteristic diagram showing the characteristics of the annealing coefficient per time during switching, Figure 13 is a characteristic diagram showing the annealing characteristics related to the throttle valve opening per hour, and Figure 14 is a characteristic diagram showing the characteristics of the annealing coefficient per hour. FIG. 12 is a diagram corresponding to FIG. 12 at the time of switching to a load region. 1... Engine 4.6... Exhaust turbo supercharger 5.7... Turbine 16... Throttle valve 27... Waste gate valve (supercharging pressure adjustment means) 46.
... Control unit 60... Actuator (throttle valve driving means) 61... Engine rotation speed sensor (engine rotation speed detection means) 64... Accelerator operation amount sensor (accelerator operation amount detection means) 81... Throttle Control means 82...Supercharging pressure control means 83...Control gain changing section 0 III]11! Bow←-:Y41P8 Fig. 6 Moon, manifold pushing force P Fig. Target manifold pushing force P Time Fig. 13 Fig. 12 Fig. 14

Claims (3)

[Claims] (1) An engine rotation speed detection means for detecting the engine rotation speed, an accelerator operation amount detection means for detecting the accelerator operation amount, and an exhaust turbo turbocharger for supercharging the engine by pressurizing intake air by a turbine driven by exhaust gas. A charger, a supercharging pressure adjusting means for adjusting the flow rate of exhaust gas to the turbine of the exhaust turbo supercharger, and a supercharging pressure adjusting means corresponding to both detected values detected by the engine rotation speed detecting means and the accelerator operation amount detecting means. In a supercharged engine equipped with a supercharging pressure control means for controlling the supercharging pressure adjusting means during high load so as to achieve a target supercharging pressure, a throttle valve driving means for driving a throttle valve, and a supercharging pressure control means for controlling the above-mentioned engine rotation. and a throttle control means for controlling the throttle valve drive means at a low load so that the opening degree corresponds to both the detection values detected by the number detection means and the accelerator operation amount detection means, the throttle control means A control device for a supercharged engine, comprising a control gain changing section that changes a control gain based on the accelerator operation amount detection means to a small value during high load. (2) The throttle control means changes the control gain to reduce the control gain based on the accelerator operation amount detection means when switching from control by the throttle control means at low load to control by the boost pressure adjustment means at high load. 2. The control device for a supercharged engine according to claim 1, further comprising a supercharged engine. (3) The throttle control means changes the control gain to greatly change the gain of the control based on the accelerator operation amount detection means when switching from control by the boost pressure adjustment means at high loads to control by the throttle control means at low loads. 2. The control device for a supercharged engine according to claim 1, further comprising a supercharged engine.