JP7003494B2 - Engine control - Google Patents

Description

The present invention relates to an engine control device.

Some engines mounted on vehicles such as automobiles are equipped with a turbocharger that supercharges intake gas using exhaust gas, and this turbocharger includes a turbine rotated by exhaust gas and this turbocharger. It has a compressor that supercharges the intake air by rotating integrally with the turbine.

An engine equipped with a turbocharger has a so-called turbo lag, which is a supercharging delay. Supercharging delay is a phenomenon in which when the accelerator pedal is stepped on, the effect of supercharging does not appear until the engine speed increases and the amount of exhaust gas increases.

Therefore, the technique described in Patent Document 1 is known as a conventional engine control device for eliminating a supercharging delay. According to Patent Document 1, when the vehicle is predicted to re-accelerate in the supercharged region, the first valve and the second valve of the intake passage are closed from the start of acceleration. I'm in control.

Japanese Patent Application Laid-Open No. 2015-214920

However, in the case described in Patent Document 1, since the first valve and the second valve are closed after predicting the re-acceleration of the vehicle, the desired supercharging state is to be reached at an early stage. There was a problem that it could not be done.

Therefore, according to the present invention, the present invention can obtain a desired supercharging pressure at an early stage when shifting from the non-supercharged region to the supercharging region by depressing the accelerator pedal, and can improve the acceleration response of the engine. It is intended to provide a control device.

One aspect of the invention of the engine control device for solving the above problems is a turbocharger that pressurizes intake air by using the exhaust gas of the engine and a bypass through which the exhaust gas bypassing the turbine of the turbocharger passes. An engine control device including a passage and a wastegate valve for adjusting the amount of exhaust gas passing through the bypass passage, the wastegate valve is operated when the accelerator opening of the accelerator pedal is larger than the predetermined accelerator opening. A control unit that performs normal open control to close the valve is provided, and the control unit closes the wastegate valve from fully open in a non-supercharging region where the accelerator opening is equal to or less than the predetermined accelerator opening. When the opening degree is controlled and the accelerator opening degree is the first accelerator opening degree as the predetermined accelerator opening degree, the wastegate valve is controlled to the first opening degree corresponding to the first accelerator opening degree, and the wastegate valve is controlled. When the accelerator opening is less than the second accelerator opening smaller than the first accelerator opening, the wastegate valve is fully closed, the accelerator opening is equal to or more than the second accelerator opening, and the first accelerator is opened. When it is less than the opening degree, the wastegate valve opening degree is controlled to be smaller than the first opening degree and to the second opening degree corresponding to the accelerator opening degree .

As described above, according to the present invention, it is possible to obtain a desired supercharging pressure at an early stage when shifting from the non-supercharging region to the supercharging region by further depressing the accelerator pedal, and it is possible to improve the acceleration response. can.

FIG. 1 is a configuration diagram of a vehicle equipped with an engine control device according to an embodiment of the present invention. FIG. 2 is a flowchart illustrating the operation of the engine control device according to the embodiment of the present invention. FIG. 3 is a timing chart illustrating the transition of the vehicle state at the time of acceleration of the vehicle equipped with the engine control device according to the embodiment of the present invention. FIG. 4 is a timing chart illustrating opening / closing control of a wastegate valve by an engine control device according to an embodiment of the present invention.

The engine control device according to the embodiment of the present invention includes a turbocharger that pressurizes intake air by using the exhaust gas of the engine, and a bypass passage through which exhaust gas bypassing the turbine of the turbocharger passes. An engine control device including a wastegate valve that adjusts the amount of exhaust gas passing through a bypass passage, and the wastegate valve is closed when the accelerator opening of the accelerator pedal is larger than a predetermined accelerator opening. A control unit that performs normal open control is provided, and the control unit controls the wastegate valve to the opening on the closed side from the fully open in the non-supercharged region where the accelerator opening is equal to or less than the predetermined accelerator opening. It is a feature. As a result, the engine control device according to the embodiment of the present invention can obtain a desired supercharging pressure at an early stage when shifting from the non-supercharging region to the supercharging region by further depressing the accelerator pedal. , Acceleration response can be improved.

Hereinafter, the engine control device according to the embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, a vehicle 1 equipped with an engine control device according to an embodiment of the present invention includes an engine 2 and an ECU (Electronic Control Unit) 3 as a control unit.

The engine 2 is composed of a four-cycle engine that performs a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke while the piston makes two reciprocations in the cylinder.

The piston housed in each cylinder is connected to the crankshaft via a connecting rod. The connecting rod is designed to convert the reciprocating motion of the piston into the rotational motion of the crankshaft.

Therefore, the engine 2 drives the vehicle 1 by reciprocating the piston by burning the air-fuel mixture in the combustion chamber 25 in the cylinder and rotating the crankshaft via the connecting rod. It is designed to generate force.

The intake port of the engine 2 is provided with an intake manifold 31 for introducing air into the combustion chamber 25. The intake manifold 31 is connected to an intake pipe 32 for sucking outside air. That is, the intake manifold 31 communicates the intake pipe 32 with the intake port of each cylinder.

The upstream portion of the intake manifold 31 forms a surge tank that temporarily stores air. An intake pressure sensor 27 is provided in the surge tank located upstream of the intake manifold 31, and the intake pressure sensor 27 detects the pressure of the intake manifold 31 as the manifold pressure and transmits the detection signal to the ECU 3. The manifold pressure is the pressure on the downstream side of the throttle valve 33 in the intake pipe 32, and changes depending on the opening degree of the throttle valve 33, the engine rotation speed, and the like.

The intake pipe 32 is provided with a throttle valve 33 for adjusting the intake air amount of the engine 2. The throttle valve 33 is configured as an electronically controlled throttle valve, and the throttle opening degree is controlled according to a command signal from the ECU 3 to adjust the intake air amount of the engine 2.

The throttle valve 33 is provided with a throttle opening sensor 28, and the throttle opening sensor 28 detects the opening degree of the throttle valve 33 and transmits a detection signal as a throttle opening to the ECU 3.

When the direction in which the fresh air of the intake pipe 32 is introduced is the intake direction, the air flow sensor 21 is provided on the upstream side in the intake direction from the throttle valve 33. The air flow sensor 21 detects the flow rate of the air flowing into the engine 2.

The exhaust port of the engine 2 is provided with an exhaust manifold 41 for exhausting the exhaust gas generated by the combustion of the air-fuel mixture in the combustion chamber 25 to the outside of the vehicle. The exhaust manifold 41 is connected to the exhaust pipe 42. That is, the exhaust manifold 41 communicates the exhaust pipe 42 with the exhaust port of each cylinder.

The exhaust pipe 42 is provided with a three-way catalyst 43 and oxygen sensors 44 and 45 with heaters. The three-way catalyst 43 purifies the exhaust gas discharged from the combustion chamber 25 of the engine 2, that is, the burnt gas.

Here, when the direction in which the exhaust gas is discharged is the exhaust direction, the oxygen sensor 44 is provided on the upstream side in the exhaust direction with respect to the three-way catalyst 43. Further, the oxygen sensor 45 is provided on the downstream side in the exhaust direction with respect to the three-way catalyst 43.

By detecting the oxygen concentration contained in the exhaust gas, the oxygen sensors 44 and 45 detect whether the air-fuel ratio is on the rich side or the lean side with respect to the stoichiometric air-fuel ratio, and transmit a detection signal to the ECU 3. do.

The oxygen sensors 44 and 45 have an output characteristic in which the output suddenly changes depending on whether the air-fuel ratio is on the rich side or the lean side with respect to the stoichiometric air-fuel ratio, or have an output characteristic linear with respect to the oxygen concentration. It consists of a sensor.

The fuel tank 51 stores gasoline as fuel for the engine 2 in a normal pressure state. The gasoline stored in the fuel tank 51 is pumped by the fuel pump 51A, then further pressurized by the high-pressure fuel pump 55, and injected from the injector 24 into the combustion chamber 25 of each cylinder.

The engine 2 is provided with a variable valve timing mechanism 26 on the intake side, and the intake timing can be adjusted by controlling the variable valve timing mechanism 26 by the ECU 3. The variable valve timing mechanism 26 may be provided on both the intake side and the exhaust side. In this case, the variable valve timing mechanism 26 is controlled by the ECU 3 to adjust the intake timing, the exhaust timing, and the valve overlap amount. can.

A canister 52 that adsorbs evaporative fuel is connected to the fuel tank 51. A purge pipe 53 is connected to the canister 52, and an intake manifold 31 is connected to the opposite end of the purge pipe 53 to which the canister 52 is connected. The evaporated fuel adsorbed in the canister 52 is introduced into the intake manifold 31 as a purge gas together with air via the purge pipe 53.

The purge pipe 53 is provided with a purge valve 54. The purge valve 54 includes a vacuum switching valve that operates by a negative pressure, and its opening and closing is controlled by the ECU 3. The ECU 3 controls the amount of purge gas introduced into the intake manifold 31 by controlling the opening and closing of the purge valve 54.

The engine 2 includes a turbocharger 60 that pressurizes intake air using exhaust gas, a bypass passage 46 through which exhaust gas bypassing the turbine 60A of the turbocharger 60 passes, and exhaust gas that passes through the bypass passage 46. A wastegate valve 65 for adjusting the amount of gas is provided.

The turbocharger 60 includes a turbine 60A arranged in an exhaust passage and a compressor 60B arranged in an intake passage. When the turbine 60A is rotated by exhaust gas, this rotation is transmitted to the compressor 60B, and the compressor 60B Supercharge the intake air.

A vacuum pump 67 that generates a negative pressure is connected to the wastegate valve 65 via a negative pressure pipe 68. The negative pressure tube 68 is provided with a vacuum switching valve 66, and the vacuum switching valve 66 is controlled by the ECU 3.

When the vacuum switching valve 66 is opened by the ECU 3, the negative pressure of the vacuum pump 67 is supplied to the wastegate valve 65 via the negative pressure pipe 68, and the wastegate valve 65 is closed.

The ECU 3 is composed of a computer unit including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an input port, and an output port.

In the ROM of the ECU 3, various control constants, various maps, and the like, as well as a program for making the computer unit function as the ECU 3 are stored. That is, when the CPU executes the program stored in the ROM, the computer unit functions as the ECU 3.

In addition to the above-mentioned airflow sensor 21, oxygen sensor 44, and 45, the input port of the ECU 3 includes an accelerator opening sensor 22, a crank angle sensor 23, a cam angle sensor 72, a cooling water temperature sensor 73, and a throttle upstream intake pressure sensor 75. Various sensors such as are connected.

The accelerator opening sensor 22 detects the accelerator opening indicating the amount of depression of the accelerator pedal 22A, and transmits a detection signal to the ECU 3.

The crank angle sensor 23 detects the rotation angle of the crankshaft of the engine 2. The ECU 3 calculates the engine speed of the engine 2 based on the detection result input from the crank angle sensor 23.

The cam angle sensor 72 detects the rotation angle of the camshaft of the engine 2. The ECU 3 determines the cylinder based on the detection result input from the cam angle sensor 72.

The cooling water temperature sensor 73 detects the temperature of the cooling water flowing through the engine 2 and transmits a detection signal to the ECU 3. The throttle upstream side intake pressure sensor 75 detects the intake pressure on the upstream side of the throttle valve 33 in the intake pipe 32, and transmits a detection signal to the ECU 3.

Various devices such as a wastegate valve 65, an injector 24, a throttle valve 33, a purge valve 54, and a VVT oil control valve 71 are connected to the output port of the ECU 3.

Here, the control method of the wastegate valve 65 includes a normal close control and a normal open control. In normal close control, the wastegate valve opening is normally closed and supercharging is performed, and the wastegate valve opening is opened so that the manifold pressure does not become too high when the engine speed is high. It is a control to make it a state.

On the other hand, the normal open control is when the wastegate valve opening is normally opened and supercharging is not performed, and the engine speed and load increase as the accelerator opening of the accelerator pedal increases. It is a control to supercharge by closing the wastegate valve.

However, in the normal open control, the acceleration response when shifting from the non-supercharged region to the supercharged region by further depressing the accelerator pedal 22A does not reach the normal close control in which supercharging is performed regardless of the accelerator opening. There is a tendency, and it cannot always be said that the desired boost pressure can be obtained at an early stage.

Therefore, in this embodiment, in order to improve the acceleration response, the turbine 60A is rotated to such an extent that supercharging is not performed even in the non-supercharged region where the accelerator opening is equal to or less than the predetermined accelerator opening. There is. Specifically, the ECU 3 controls the wastegate valve 65 to the opening on the closed side from the fully open in the non-supercharged region where the accelerator opening is equal to or less than the predetermined accelerator opening. That is, in this embodiment, when the accelerator opening degree is in the non-supercharging region equal to or less than the predetermined accelerator opening degree, the ECU 3 controls the opening degree to be closer to the closed side than fully open.

Here, the non-supercharged area and the supercharged area are classified according to the accelerator opening degree. The non-supercharged region is a region of the accelerator opening where the manifold pressure is equal to or lower than the atmospheric pressure. The supercharging region is a region of the accelerator opening where the manifold pressure becomes larger than the atmospheric pressure.
In other words, the area where supercharging is not performed is the non-supercharged area, and the area where supercharging is performed is the supercharged area. The predetermined accelerator opening is the accelerator opening that is the upper limit of the non-supercharged region.

In this embodiment, the ECU 3 fully opens the wastegate valve 65 so that the turbine rotation speed of the turbocharger 60 becomes equal to or less than the predetermined turbine rotation speed when the accelerator pedal 22A is depressed in the non-supercharged region. Control the opening on the closed side. Here, the predetermined turbine rotation speed is a rotation speed corresponding to a predetermined accelerator opening degree and is a rotation speed for obtaining the manifold pressure immediately before the start of supercharging.

Further, in the ECU 3, when the accelerator pedal 22A is depressed in the non-supercharged region, the wastegate valve 65 increases the opening degree of the wastegate valve 65 corresponding to the predetermined accelerator opening degree as the engine speed increases. Is controlled to the opening on the closed side from the fully open.

Further, when the accelerator opening degree is the first accelerator opening degree as the predetermined accelerator opening degree, the ECU 3 controls the wastegate valve 65 to the first opening degree corresponding to the first accelerator opening degree. Further, when the accelerator opening degree is smaller than the first accelerator opening degree and less than the second accelerator opening degree, the ECU 3 fully closes the wastegate valve 65.

Further, when the accelerator opening is equal to or greater than the second accelerator opening and less than the first accelerator opening, the ECU 3 wastes the second opening smaller than the first opening and according to the accelerator opening. The opening degree of the gate valve 65 is controlled. Since the second opening degree is an opening degree corresponding to the accelerator opening degree, it is not a fixed value but an opening degree having a correlation with the accelerator opening degree.

Here, as the accelerator opening degree increases, the intake amount and the exhaust gas amount increase, and the turbine rotation speed tends to increase, so that the manifold pressure increases. Therefore, in this embodiment, the second opening degree is set to be larger as the accelerator opening degree is larger. This makes it possible to prevent the turbine rotation speed from rising above the rotation speed at which supercharging starts in the non-supercharged region.

In the ECU 3, when the accelerator pedal 22A is depressed in the non-supercharged region, the turbine rotation speed of the turbocharger 60 corresponds to the predetermined accelerator opening and obtains the manifold pressure immediately before the start of supercharging. The wastegate valve 65 may be controlled to an opening degree on the closed side rather than the fully open side so that the number is constant. Here, the predetermined turbine rotation speed is a rotation speed corresponding to a predetermined accelerator opening degree and is a rotation speed for obtaining the manifold pressure immediately before the start of supercharging.

In this embodiment, the wastegate valve opening is adjusted based on the accelerator opening, but it is based on the driver's required torque obtained from parameters such as fuel injection amount, ignition timing, and intake air amount in addition to the accelerator opening. The wastegate valve opening may be adjusted.

The operation of the engine control device according to the present embodiment configured as described above will be described with reference to the flowchart of FIG.

In FIG. 2, the ECU 3 determines whether or not the accelerator opening is larger than the first accelerator opening (step S1), and if it is larger than the first accelerator opening, the accelerator opening is in the supercharging region. Supercharging control is performed (step S2), and the current operation is terminated. In this supercharging control, the ECU 3 controls the wastegate valve 65 to the opening degree at which the supercharging pressure is obtained.

In this embodiment, as will be described later, the wastegate valve opening is controlled to be smaller as the accelerator opening is larger. Further, after the accelerator opening degree has increased to a predetermined value, the wastegate valve 65 is controlled to be kept constant with a small opening degree.

When the accelerator opening is equal to or less than the first accelerator opening in step S1, the ECU 3 determines whether or not the accelerator opening is equal to or less than the first accelerator opening and equal to or greater than the second accelerator opening (step S3). ..

When the accelerator opening is equal to or less than the first accelerator opening and equal to or greater than the second accelerator opening in step S3, the ECU 3 sets the wastegate valve 65 (referred to as WGV in the figure) to the opening corresponding to the accelerator opening. It is controlled (step S4), and the current operation is terminated.

When the accelerator opening is not less than or equal to the first accelerator opening and not more than or equal to the second accelerator opening in step S3, the ECU 3 determines whether or not the accelerator opening is less than the second accelerator opening (step S5). ).

When the accelerator opening is less than the second accelerator opening in step S5, the ECU 3 fully closes the wastegate valve 65 (denoted as WGV in the figure) (step S6), and ends the current operation.

If the accelerator opening is not less than the second accelerator opening in step S5, the ECU 3 ends the current operation.

The operation of FIG. 2 will be described with reference to the timing chart of FIG. This timing chart shows the transition of the vehicle state when the vehicle accelerates.

FIG. 3 shows changes in the accelerator opening, the wastegate valve opening (referred to as WGV opening in the figure), and the manifold pressure. The wastegate valve opening in the figure indicates the opening when the engine speed is relatively large (indicated as Ne large in the figure) by a alternate long and short dash line, and the opening when the engine speed is relatively small (indicated as Ne large). In the figure, it is indicated by Ne small) by a solid line. The wastegate valve opening when the engine speed is relatively high is set to be larger than when the engine speed is relatively low. This is because the larger the engine speed, the larger the amount of exhaust gas from the engine, and it is necessary to reduce the amount of exhaust gas flowing to the turbine 60A to the extent that supercharging is not started.

In FIG. 3, the accelerator opening degree is 0 at the time t0 in the initial state, and the wastegate valve opening degree is fully opened. After that, when the accelerator opening slightly becomes larger than 0 at time t1, the wastegate valve opening is fully closed.

After that, when the accelerator opening increases to the second accelerator opening at time t2, the wastegate valve opening opens at once from the fully closed to the second opening (referred to as the second WGV opening in the figure).

After that, as the accelerator opening increases, the wastegate valve opening increases.

After that, when the accelerator opening increases to the first accelerator opening at time t3, the wastegate valve 65 is set to the first opening (referred to as the first WGV opening in the figure). The wastegate valve opening degree from time t2 to time t3 is large when the engine speed is high, and small when the engine speed is low. Therefore, the larger the engine speed, the larger the wastegate valve opening corresponding to the predetermined accelerator opening is controlled. The second accelerator opening for opening the wastegate valve opening from the fully closed to the second opening may be set smaller as the engine speed increases. As the engine speed increases, the amount of exhaust gas from the engine increases. In this case, the wastegate valve 65 can be opened early to adjust the amount of exhaust gas flowing to the turbine 60A. As a result, it is possible to prevent the turbine rotation speed from rising above the rotation speed at which supercharging starts.

In the supercharging region after time t3, the wastegate valve opening is controlled to decrease as the accelerator opening increases. Further, after the accelerator opening degree has increased to a predetermined value, the wastegate valve 65 is controlled to be kept constant with a small opening degree (for example, an opening degree of 10%).

It should be noted that keeping the wastegate valve 65 constant at a small opening such as 10% is an example, and the wastegate valve opening may be controlled to be 0 (fully closed). That is, the wastegate valve opening degree when the accelerator opening degree becomes large to a predetermined accelerator opening degree is not limited to a small opening degree such as an opening degree of 10%, and may be an opening degree of 0. In this embodiment, the opening degree of the wastegate valve 65 is collectively referred to as a valve closed state when the opening degree is 0 and when the opening degree is small such as 10%.

Further, at time t0 in the initial state, the accelerator opening is 0, the wastegate valve opening is fully opened, and when the accelerator opening is slightly larger than 0, the wastegate valve opening is fully closed. When the degree is 0, the wastegate valve opening may be fully closed. In this case, the exhaust gas has flowed into the turbine 60A from the state where the accelerator opening degree is 0, and it is possible to start supercharging at an early stage.

Next, the opening / closing control of the wastegate valve will be described with reference to the timing chart of FIG. FIG. 4 shows the transition from the opening of the wastegate valve 65 to the opening of the valve and the return to the opening of 0 again.

The transition of the wastegate valve 65 at the time of opening in this timing chart corresponds to the transition of the wastegate valve opening degree in FIG. 3 from the time t1 to the time t3. The solid line shows the transition of this embodiment, and the broken line shows the transition of the comparative example.

In FIG. 4, since the accelerator opening degree (not shown) is less than the second accelerator opening degree in FIG. 3 at the time t10 in the initial state, the wastegate valve opening degree is set to 0 (fully closed).

After that, at time t11, the accelerator opening becomes large up to the second accelerator opening in FIG. 3, and the wastegate valve opening is opened at once to the opening corresponding to the second opening.

After that, at time t12, the accelerator opening is opened to the fully opened state, and the wastegate valve opening is also opened to a large opening corresponding to the accelerator opening.

After that, at time t13, the accelerator opening is reduced, and the wastegate valve opening is also reduced accordingly.

After that, at time t14, the accelerator opening is reduced to the second accelerator opening in FIG. 3, so that the wastegate valve opening is set to 0 (fully closed).

As described above, in this embodiment, the minute opening degree is skipped when the wastegate valve 65 is opened and closed. As a result, it is possible to prevent the wastegate valve 65 from becoming a minute opening, and it is possible to prevent the generation of a collision sound called chattering of the wastegate valve 65 at a minute opening.

As described above, according to the present embodiment, the ECU 3 controls the wastegate valve 65 to the opening degree on the closed side from the fully open side in the non-supercharged region where the accelerator opening degree is equal to or less than the predetermined accelerator opening degree.

As a result, when the accelerator opening is in the non-supercharged region less than the predetermined accelerator opening, the exhaust gas can be supplied to the turbine 60A by controlling the wastegate valve 65 to the opening on the closed side from the fully open state. As a result, the turbine 60A can be rotated to such an extent that supercharging is not performed even in the non-supercharged region.

As a result, when the accelerator pedal 22A is further depressed to shift from the non-supercharged region to the supercharged region, a desired supercharging pressure can be obtained at an early stage, and acceleration response can be improved.

Further, according to the present embodiment, in the ECU 3, when the accelerator pedal 22A is depressed in the non-supercharged region, the turbine rotation speed of the turbocharger 60 corresponds to the predetermined accelerator opening and immediately before the start of supercharging. The wastegate valve 65 is controlled to an opening degree on the closed side rather than fully open so that the turbine rotation speed or less at which the manifold pressure is obtained is equal to or lower.

As a result, in the non-supercharged region, the predetermined accelerator opening is in the state immediately before the start of supercharging, and the turbine 60A can be rotated to such an extent that supercharging is not performed in this state. The desired supercharging pressure can be obtained at an early stage during the transition to the supercharging region.

Further, the turbine 60A can be rotated to the extent that supercharging is not performed in the non-supercharged region, and it is desired at an early stage when shifting from the non-supercharged region to the supercharged region by further depressing the accelerator pedal 22A. The supercharging pressure can be obtained, and the acceleration response can be improved.

Further, according to the present embodiment, when the accelerator opening is the first accelerator opening as the predetermined accelerator opening, the ECU 3 controls the wastegate valve 65 to the first opening corresponding to the first accelerator opening. do. Further, when the accelerator opening degree is smaller than the first accelerator opening degree and less than the second accelerator opening degree, the ECU 3 fully closes the wastegate valve 65. Further, when the accelerator opening is equal to or greater than the second accelerator opening and less than the first accelerator opening, the ECU 3 wastes the second opening smaller than the first opening and according to the accelerator opening. The opening degree of the gate valve 65 is controlled.

As a result, in the region where the accelerator opening is less than the second accelerator opening, the opening of the wastegate valve 65 is set to 0, and the wastegate valve 65 is fully closed, so that the turbine 60A is positively driven by the exhaust gas. Can be rotated. Therefore, the driver can obtain a desired acceleration feeling when the accelerator pedal 22A is depressed.

On the other hand, in the region above the second accelerator opening degree, the controllability of the wastegate valve 65 can be improved by setting the opening degree of the wastegate valve 65 to the second opening degree according to the accelerator opening degree.

Further, when the accelerator opening increases from 0 and becomes equal to or higher than the second accelerator opening, the wastegate valve 65 opens from the opening 0 to the second opening, so that the wastegate valve 65 is fully closed. It is possible to prevent the wastegate valve 65 from being chattered at a minute opening, and it is possible to prevent chattering of the wastegate valve 65 at a minute opening.

Further, according to the present embodiment, when the accelerator pedal 22A is depressed in the non-supercharged region, the ECU 3 obtains a manifold pressure immediately before the start of supercharging in which the turbine rotation speed corresponds to the predetermined accelerator opening. The wastegate valve 65 is controlled to have an opening degree on the closed side rather than fully open so that the rotation speed becomes constant.

In this way, by setting the manifold pressure immediately before the start of supercharging by keeping it constant at a predetermined turbine speed corresponding to the predetermined accelerator opening in the non-supercharged region, supercharging from the non-supercharged region by further depressing the accelerator pedal 22A. When moving to the region, the desired boost pressure can be obtained at an early stage, and the acceleration response can be improved.

Further, according to the present embodiment, when the accelerator pedal 22A is depressed in the non-supercharged region, the larger the engine speed, the larger the opening degree of the wastegate valve 65 corresponding to the predetermined accelerator opening degree. As described above, the wastegate valve 65 is controlled to have an opening degree on the closed side rather than the fully open side.

As a result, as the engine speed increases, the intake amount and the exhaust gas amount increase, so that it is possible to prevent the engine speed from becoming too high during the transition from the non-supercharged region to the supercharged region.

Although embodiments of the present invention have been disclosed, it will be apparent to those skilled in the art that modifications may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

2 Engine 3 ECU (control unit)
22A Accelerator pedal 46 Bypass passage 60 Turbocharger 60A Turbine 65 Wastegate valve

Claims (2)

A turbocharger that uses the exhaust gas of the engine to pressurize the intake air,
A bypass passage through which exhaust gas bypassing the turbine of the turbocharger passes, and
An engine control device comprising a wastegate valve for adjusting the amount of exhaust gas passing through the bypass passage.
It is equipped with a control unit that performs normal open control that closes the wastegate valve when the accelerator opening of the accelerator pedal is larger than the predetermined accelerator opening.
The control unit
In the non-supercharging region where the accelerator opening is equal to or less than the predetermined accelerator opening.
The wastegate valve is controlled to the opening side from the fully open side to the closed side.
When the accelerator opening is the first accelerator opening as the predetermined accelerator opening, the wastegate valve is controlled to the first opening corresponding to the first accelerator opening.
When the accelerator opening is less than the second accelerator opening smaller than the first accelerator opening, the wastegate valve is fully closed.
When the accelerator opening is equal to or greater than the second accelerator opening and less than the first accelerator opening, the second opening is smaller than the first opening and corresponding to the accelerator opening. An engine control device characterized by controlling the opening degree of a wastegate valve . A turbocharger that uses the exhaust gas of the engine to pressurize the intake air,
A bypass passage through which exhaust gas bypassing the turbine of the turbocharger passes, and
An engine control device comprising a wastegate valve for adjusting the amount of exhaust gas passing through the bypass passage.
It is equipped with a control unit that performs normal open control that closes the wastegate valve when the accelerator opening of the accelerator pedal is larger than the predetermined accelerator opening.
The control unit
When the accelerator pedal is depressed in a non-supercharged region where the accelerator opening is equal to or less than the predetermined accelerator opening .
The turbine speed of the turbocharger is constant at a predetermined turbine speed that corresponds to the predetermined accelerator opening and obtains the manifold pressure immediately before the start of supercharging.
An engine control device characterized in that the wastegate valve is controlled to an opening degree on the closed side rather than a fully open side.

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