FR3070434A1 - MOTOR CONTROL DEVICE - Google Patents

Abstract

An electronic control unit (ECU) controls a discharge valve at an open degree close to a closed state with respect to a fully open state (step S4) in a non-boosting zone in which an opening degree of accelerator becomes equal to or less than a predetermined accelerator opening degree (NO at step S1). The ECU controls the discharge valve to an opening degree close to a closed state with respect to a fully open state so that a turbine rotational speed of a turbocharger becomes equal to or less than a speed. predetermined turbine rotation system providing manifold pressure immediately before a boost operation begins in response to the predetermined throttle opening degree when an accelerator pedal is depressed into the non-boosting zone.

Description

MOTOR CONTROL DEVICE

This invention relates to a motor control device.

As an engine mounted on a vehicle such as an automobile, an engine comprising a turbocharger for supercharging intake air using an exhaust gas is known and the turbocharger comprises a turbine rotated by a gas exhaust and an air compressor rotated at the same time as the turbine to supercharge the intake air.

In the engine with the turbocharger, a boost delay occurs and is called turbo lag. The supercharging delay is a phenomenon in which a supercharging effect does not appear until the engine speed increases and the volume of exhaust gas increases when an accelerator pedal is depressed further.

Here, a technology described in document JP 2015-214920 A is known as a conventional engine control device for solving a supercharging delay. In the technology described in document JP 2015-214920 A, a first valve and a second valve in an intake passage are controlled to be closed from an instant of acceleration start when one expects to that a vehicle is accelerated again in a supercharging zone.

However, in the technology described in JP 2015-214920 A, since the first valve and the second valve are closed after expecting further acceleration of the vehicle, a problem arises in that a desired state of overeating cannot be achieved at an early stage.

Here, an object of the present invention is to provide an engine control device capable of providing a desired boost pressure at an early stage when switching from a non-boost area to a boost area depending on increased amount of pressure on the accelerator pedal and improved acceleration responsiveness.

According to aspects of the present invention there is provided an engine control device for an engine, comprising a turbocharger pressurizing intake air using an engine exhaust gas, a bypass passage formed for bypassing a turbine of the turbocharger so that an exhaust gas passes through it, a relief valve adjusting an amount of the exhaust gas passing through the bypass passage, the engine control device comprising: a control unit performing a control normal opening to close the relief valve when an accelerator opening degree of an accelerator pedal is greater than a predetermined accelerator opening degree, in which the control unit controls the valve discharge to an opening degree close to a closed state compared to a fully open state in a zone of no overfeeding of the accelerating opening degree equal to or less than the predetermined throttle opening degree.

In this way, according to this invention, it is possible to obtain a desired boost pressure at an early stage when passing from the non-boost area to the boost area as a function of an increase in the amount of pressure on the accelerator pedal and improve acceleration responsiveness.

According to one embodiment, when the accelerator pedal is depressed in the non-boost zone, the control unit controls the relief valve until it reaches an opening degree close to a closed state with respect to in a fully open state such that a turbine rotational speed of the turbocharger becomes equal to or less than a predetermined turbine rotational speed to obtain a manifold pressure immediately before a boost operation begins in response to the degree of '' predetermined throttle opening.

According to one embodiment, the control unit controls the relief valve until it reaches a first degree of opening corresponding to a first degree of accelerator opening when the degree of accelerator opening is the first accelerator opening degree corresponding to the predetermined accelerator opening degree. The control unit controls the relief valve until it reaches a fully closed state when the accelerator opening degree is less than a second accelerator opening degree less than the first opening degree. accelerator. The control unit controls the degree of opening of the relief valve until it reaches a second degree of opening less than the first degree of opening and corresponding to the degree of accelerator opening when the degree of accelerator opening is greater than or equal to the second degree of accelerator opening and is less than the first degree of accelerator opening.

According to one embodiment, when the accelerator pedal is depressed in the non-boost zone, the control unit controls the relief valve until it reaches an opening degree close to a closed state with respect to in a fully open state so that the turbine rotation speed becomes homogeneous with the predetermined turbine rotation speed to obtain a manifold pressure immediately before a boost operation begins in response to the degree of accelerator opening predetermined.

According to one embodiment, when the accelerator pedal is depressed in the non-supercharging zone, the control unit controls the relief valve to an opening degree close to a closed state compared to a state fully open so that the degree of opening of the relief valve corresponding to the predetermined degree of throttle opening increases with increasing engine speed.

The present invention will be described in detail below with reference to the accompanying drawings in which:

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 flow chart illustrating an operation of a motor control device according to an embodiment of the present invention;

FIG. 3 is a timing diagram illustrating a transition from a state of the vehicle at the time of acceleration of a vehicle equipped with the engine control device according to an embodiment of the present invention; and

FIG. 4 is a timing diagram illustrating the control of opening and closing of a wastegate valve by the engine control device according to an embodiment of the present invention.

An engine control device according to the present invention is an engine control device for an engine, comprising a turbocharger pressurizing intake air using an engine exhaust gas, a bypass passage formed for bypassing a turbine of the turbocharger so that an exhaust gas passes through it, a relief valve adjusting an amount of the exhaust gas passing through the bypass passage, the engine control device comprising: a control unit performing a control normal opening to close the relief valve when an accelerator opening degree of an accelerator pedal is greater than a predetermined accelerator opening degree, in which the control unit controls the valve discharge to an opening degree close to a closed state compared to a fully open state in a non-overfeed zone of the opening degree of accelerator equal to or less than the predetermined accelerator opening degree. Consequently, the engine control device according to the embodiments of the present invention can provide a desired boost pressure at an early stage when switching from the non-boost area to the boost area in accordance with an increase. amount of pressure on the accelerator pedal and can improve acceleration responsiveness.

Hereinafter, an internal combustion engine control device according to embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, a vehicle 1 equipped with a motor control device according to embodiments of this invention comprises a motor 2 and an electronic control unit (ECU) 3 corresponding to a control unit.

Engine 2 is configured as a four-stroke engine which performs a series of four strokes including an intake stroke, a compression stroke, an expansion stroke and an exhaust stroke while a piston alternately moves in a cylinder in a double back and forth.

The piston housed in each cylinder is connected to a crankshaft by a connecting rod. The connecting rod is used to convert the reciprocating movement of the piston into the rotational movement of the crankshaft.

Thus, the engine 2 is used to generate motive power to drive the vehicle 1 by moving the piston alternately by the combustion of an air-fuel mixture of fuel and air in a combustion chamber 25 at the inside the cylinder and by turning the crankshaft via the connecting rod.

An intake port of the engine 2 is provided with an intake manifold 31 intended to introduce air into the combustion chamber 25. The intake manifold 31 is connected to an intake pipe 32 for sucking in outside air. That is, the intake manifold 31 causes the intake pipe 32 to communicate with the intake port of each cylinder.

An upstream part of the intake manifold 31 constitutes a buffer tank for temporarily storing the air. The buffer tank which is the upstream part of the intake manifold 31 is provided with an intake pressure sensor 27 and the intake pressure sensor 27 detects an intake manifold pressure 31 as the manifold pressure and transmits a detection signal to the ECU 3. The manifold pressure is a pressure on the downstream side of a butterfly valve 33 of the intake pipe 32 and is modified as a function of the degree of opening of the butterfly valve 33, of the engine speed or the like.

The inlet pipe 32 is provided with the butterfly valve 33 for adjusting the amount of engine intake air 2. The butterfly valve 33 is configured as an electronically controlled butterfly valve and is used to adjust the amount of air engine 2 intake when the throttle opening degree is controlled in response to the ECU 3 instruction signal.

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

A direction in which fresh air is introduced into the intake pipe 32 is defined as the intake direction and an air flow sensor 21 is provided on the upstream side of the butterfly valve 33 in the intake direction . The air flow sensor 21 detects an air flow circulating in the motor 2.

An exhaust port of the engine 2 is provided with an exhaust manifold 41 for discharging exhaust gases generated by the combustion of the air-fuel mixture in the combustion chamber 25 towards the outside of the vehicle. The exhaust manifold 41 is connected to the exhaust pipe 42. In other words, the exhaust manifold 41 causes the exhaust pipe 42 to communicate 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 a heating device. The three-way catalyst 43 is used to purify an exhaust gas, that is to say a burnt gas discharged from the combustion chamber 25 of the engine 2.

Here, when a direction in which the exhaust gases are exhausted is defined as the exhaust direction, the oxygen sensor 44 is provided on the upstream side of the three-way catalyst 43 in the exhaust direction. In addition, the oxygen sensor 45 is provided on the downstream side of the three-way catalyst 43 in the direction of the exhaust.

The oxygen sensors 44 and 45 detect whether the air-fuel ratio is on the rich side or the lean side compared to the stoichiometric air-fuel ratio by detecting an oxygen concentration in the exhaust gases and transmit a detection signal to the ECU 3.

Each of the oxygen sensors 44 and 45 is configured as a sensor having an output characteristic in which an output changes abruptly when the air-fuel ratio changes to the rich side or the lean side relative to the stoichiometric air-fuel ratio or to a sensor which has a linear output characteristic with respect to the oxygen concentration.

A 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 supplied under pressure by the fuel pump 51 A, is then pressurized by a high pressure fuel pump 55 and is injected from an injector 24 into the combustion chamber 25 of each cylinder.

The engine 2 comprises a variable distribution mechanism 26 on the intake side and is capable of adjusting an intake synchronization by controlling the variable distribution mechanism 26 by the ECU 3. In addition, the variable distribution mechanism 26 can be provided both on the intake side and the exhaust side. In this case, when the variable distribution mechanism 26 is controlled by the ECU 3, the intake timing, the exhaust timing and the degree of valve crossing can be adjusted.

A cartridge 52 intended to adsorb the evaporated fuel is connected to the fuel tank 51. A purge pipe 53 is connected to the cartridge 52 and the intake manifold 31 is connected at an end opposite to the connection side of the purge hose to the cartridge 52. The evaporated fuel absorbed in the cartridge 52 is introduced into the intake manifold 31 through the purge pipe 53 together with air as the purge gas.

The purge pipe 53 is provided with a purge valve 54. The purge valve is configured as a vacuum switching valve actuated by negative pressure and is controlled by the ECU 3 in opening and closing. The ECU 3 controls the quantity of purge gas introduced into the intake manifold 31 by controlling the opening and closing of the purge valve 54.

The engine 2 is provided with a turbocharger 60 which pressurizes an intake air using an exhaust gas, a bypass passage 46 formed to bypass a turbine 60A of the turbocharger 60 so that a gas d exhaust passes through it, and a discharge valve 65 which adjusts the quantity of exhaust gas passing through the bypass passage 46.

The turbocharger 60 comprises the turbine 60A which is arranged in the exhaust passage and a compressor 60B which is arranged in the intake passage and the rotation of the turbine 60A due to the exhaust gases is transmitted to the compressor 60B so that the compressor 60B supercharges the intake air.

A vacuum pump 67 which generates negative pressure is connected to the relief valve 65 via a negative pressure pipe 68. The negative pressure pipe 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 relief valve 65 through the negative pressure pipe 68 so that the relief valve 65 is closed.

The ECU 3 is configured as a computer unit comprising a central processing unit (in English: CPU or Central Processing Unit), a random access memory (in English: RAM or Random Access Memory), a read only memory (in English: ROM or Read Only Memory), a flash memory, an input port and an output port.

The ECU 3 ROM stores a program to make the computer unit work like the ECU 3 with various control integers, different cards or the like. In other words, when the CPU executes the program stored in the ROM, the computer unit functions like the ECU 3.

Different sensors such as an accelerator opening degree sensor 22, a crankshaft angle sensor 23, a cam angle sensor 72, a coolant temperature sensor 73 and a pressure sensor d the inlet upstream of the throttle valve 75 are connected to the input terminal of the ECU 3 in addition to the air flow sensor 21 and the oxygen sensors 44 and 45.

The accelerator opening degree sensor 22 detects an accelerator opening degree designating an amount of pressure on an accelerator pedal 22A and transmits a detection signal to the ECU 3.

The crankshaft angle sensor 23 is used to detect the rotation angle of the crankshaft of the engine 2. The ECU 3 is used to calculate the rotation speed of the engine 2 based on the detection result provided by the sensor d crankshaft angle 23.

The cam angle sensor 72 is used to detect the rotation angle of the camshaft of the engine 2. The ECU 3 determines the cylinder according to the detection result supplied by the cam angle sensor 72 .

The coolant temperature sensor 73 detects a coolant temperature circulating in the engine 2 and transmits a detection signal to the ECU 3. The inlet throttle pressure sensor 75 detects a pressure of inlet upstream relative to the butterfly valve 33 in the inlet pipe 32 and transmits a detection signal to the ECU 3.

Various devices such as the relief valve 65, the injector 24, the butterfly valve 33, the purge valve 54 and a variable control oil control valve (in English: VVT or Variable Valve Timing) 71 are connected to the ECU output terminal 3.

Here, a normal closing command and a normal opening command are known as the type of control of the relief valve 65. The normal closing command designates a command in which the boost operation is performed while the degree the relief valve opening is set to a closed state in a normal state and the degree of opening of the relief valve is set to an open state so that the manifold pressure does not increase too much when the motor rotation speed is high.

Furthermore, the normal opening command designates a command in which the boost operation is not executed while the degree of opening of the relief valve is set to an open state in a normal case and in which the the supercharging operation is performed while the degree of opening of the relief valve is set to a closed state when the engine speed or the engine load increases with an increase in the degree of opening the accelerator pedal.

However, in normal opening control, there is a tendency for acceleration reactivity from the no-boost zone to the boost zone depending on an increase in the amount of pressure on the accelerator pedal. 22A does not reach the normal closing command for carrying out the supercharging operation regardless of the degree of accelerator opening. Consequently, it cannot necessarily be said that a desired boost pressure can be obtained at an early stage.

Here, in this embodiment, in order to improve the reactivity to acceleration, the turbine 60A rotates to a degree not carrying out the supercharging operation either in the non-supercharging zone in which the degree of opening d The accelerator is equal to or less than a predetermined degree of accelerator opening. More particularly, the ECU 3 controls the relief valve 65 up to the degree of opening close to the closed state relative to the fully open state in the non-boost zone in which the degree of accelerator opening becomes equal to or less than the predetermined throttle opening degree.

That is, in this embodiment, the ECU 3 controls the relief valve to the degree of opening close to the closed state compared to the fully open state when the degree of opening throttle is in the no-boost area of the predetermined throttle opening degree or less.

Here, the non-supercharging zone and the supercharging zone are distinguished from each other by the degree of accelerator opening. The non-supercharging zone designates an area of the accelerator opening degree in which the manifold pressure becomes equal to or less than atmospheric pressure. The boost zone designates an area of the accelerator opening degree in which the manifold pressure becomes higher than atmospheric pressure.

In other words, an area without boost operation is the no boost area and an area with the boost operation is the boost area. In addition, the predetermined throttle opening degree designates the accelerator opening degree corresponding to the upper limit of the non-overfeed zone.

In this embodiment, when the accelerator pedal 22A is depressed in the no-boost zone, the ECU 3 controls the relief valve 65 to an opening degree close to a closed state with respect to a fully open state so that the rotation speed of the turbine of the turbocharger 60 becomes equal to or less than a predetermined turbine rotation speed. Here, the predetermined turbine rotation speed designates a rotation speed corresponding to the predetermined degree of accelerator opening and a rotation speed to obtain a manifold pressure immediately before the start of a boost operation.

In addition, when the accelerator pedal 22A is depressed in the non-boost area, the ECU 3 controls the relief valve 65 to an opening degree close to a closed state compared to a fully open state so that the degree of opening of the relief valve 65 corresponding to the degree of opening of the predetermined accelerator increases as the speed of rotation of the engine increases.

In addition, when the accelerator opening degree is a first accelerator opening degree as a predetermined accelerator opening degree, the ECU 3 controls the relief valve 65 to a first degree opening corresponding to the first degree of accelerator opening.

In addition, when the accelerator opening degree is less than a second accelerator opening degree less than the first accelerator opening degree, the ECU 3 controls the relief valve 65 to make it reach a completely closed state.

In addition, when the accelerator opening degree is greater than or equal to the second accelerator opening degree and less than the first accelerator opening degree, the ECU 3 controls the degree of opening of the valve. discharge 65 to reach the second degree of accelerator opening, less than the first degree of accelerator opening and corresponding to the degree of accelerator opening. Furthermore, since the second degree of opening is the degree of opening corresponding to the degree of opening of the accelerator, the degree of opening is not a fixed value and has a correlation with the degree of opening of accelerator.

Here, since the intake volume and the amount of exhaust gas increase as the throttle opening degree increases, so that the rotational speed of the turbine easily increases, the manifold pressure increases. Here in this embodiment, the second degree of opening is set to increase as the degree of accelerator opening increases. As a result, it is possible to prevent a problem in which the rotational speed of the turbine increases to one or more rotational speed and starts a boost operation in the non-boost area.

In addition, when the accelerator pedal 22A is depressed in the non-supercharging zone, the ECU 3 can control the relief valve 65 until it reaches an opening degree close to a closed state with respect to a fully open state so that the turbine rotational speed of the turbocharger 60 becomes homogeneous at the predetermined turbine rotational speed to obtain the manifold pressure immediately before the boost operation begins in response to the degree of opening d 'predetermined accelerator. Here, the predetermined turbine rotation speed designates a rotation speed corresponding to the predetermined degree of accelerator opening and a rotation speed to obtain the manifold pressure immediately before the start of a boost operation.

In this embodiment, the degree of opening of the relief valve is adjusted according to the degree of opening of the accelerator, but the degree of opening of the relief valve can be adjusted according to the torque requested by the driver from fuel injection parameters, from an intake volume other than the throttle opening degree.

An operation of the motor control device according to this embodiment with the configuration described above will be described with reference to the flow chart of FIG. 2.

In FIG. 2, the ECU 3 determines whether the degree of accelerator opening is greater than the first degree of accelerator opening (step SI). Since the throttle opening degree is in the boost zone when the throttle opening degree is greater than the first throttle opening degree, the ECU executes a boost command (step S2) and ends the operation in progress. In the boost control, the ECU 3 controls the relief valve 65 to the degree of opening capable of generating a boost pressure.

In this embodiment, as will be described later, the degree of opening of the relief valve is controlled so as to decrease as the degree of opening of the accelerator increases. In addition, the relief valve 65 is controlled to be homogeneous at a low degree of opening after the degree of accelerator opening has increased to a predetermined value.

When the accelerator opening degree is equal to or less than the first accelerator opening degree in step SI, the ECU 3 determines whether the accelerator opening degree is less than or equal to the first degree d accelerator opening and if it is greater than or equal to the second degree of accelerator opening (step S3).

When the accelerator opening degree is equal to or less than the first accelerator opening degree and is greater than or equal to the second accelerator opening degree in step S3, the ECU 3 controls the soupage of discharge 65 (called SD in the drawing) up to the degree of opening corresponding to the degree of opening of the accelerator (step S4) and ends the operation in progress.

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

When the throttle opening degree is less than the second throttle opening degree in step S5, the ECU 3 controls the relief valve 65 (called SD in the drawing) to a fully closed state (step S6) and ends the operation in progress.

When the accelerator opening degree is not less than the second accelerator opening degree in step S5, the ECU 3 terminates the operation in progress.

An operation according to FIG. 2 will be described with reference to the timing diagram of FIG. 3. The timing diagram illustrates a transition from the state of the vehicle when the vehicle is accelerated.

Figure 3 illustrates a transition of the throttle opening degree, the opening degree of the relief valve (called SD opening degree in the drawing) and the manifold pressure. In the representation of the degree of opening of the relief valve in the drawing, the degree of opening (called large Ne in the drawing) when the speed of rotation of the motor is relatively high is represented by the line mixed with a dash and the degree of opening (called low Ne in the drawing) when the speed of rotation of the motor is relatively low is represented by the solid line. The degree of opening of the relief valve when the engine speed is relatively high is set to have a large degree of opening compared to a case in which the engine speed is relatively low. This is because it is necessary to reduce the amount of exhaust gas flowing through the turbine 60A to a degree at which the supercharging operation does not start since the amount of engine exhaust gas increases when the speed engine rotation increases.

In FIG. 3, the degree of opening of the accelerator is equal to 0 and the degree of opening of the relief valve is completely open at the instant t0 of the initial state. Then, when the degree of accelerator opening becomes slightly greater than at time t1, the degree of opening of the relief valve is completely closed.

Then, when the degree of accelerator opening increases to the second degree of accelerator opening at time t2, the degree of opening of the relief valve is opened up to the second degree of opening ( called second degree of opening of SD in the drawing) from the completely closed state at once.

Then, the degree of opening of the relief valve increases as the degree of opening of the accelerator increases.

Then, when the accelerator opening degree increases to the first accelerator opening degree at time t3, the relief valve 65 is set to the first opening degree (called first opening degree of SD in the drawing). For the degree of relief valve opening from time t2 to time t3, the degree of opening is large when the engine speed is high and the degree of opening is low when the speed of motor rotation is low. Thus, the degree of opening of the relief valve corresponding to the degree of opening of the predetermined accelerator is controlled to increase when the speed of rotation of the engine increases. In addition, the second degree of throttle opening to open the degree of opening of the relief valve to the second degree of opening from the fully closed state can be set to be low when the rotation speed of the engine increases. Since the amount of exhaust gas from the engine increases as the engine speed increases, it is possible to adjust the amount of exhaust gas flowing in the turbine 60A by opening the relief valve 65 at one stage. early in this case. As a result, it is possible to prevent a problem that the rotational speed of the turbine increases to one or more rotational speed at which a boost operation starts.

In the boost zone after time t3, the degree of opening of the relief valve is controlled to decrease as the degree of accelerator opening increases. In addition, the relief valve 65 is controlled to be homogeneous at a low degree of opening (for example, the degree of opening of 10%) after the degree of opening of the accelerator has increased to a value predetermined.

In addition, a case of maintaining the relief valve 65 as being homogeneous at a low degree of opening such as 10% is an example and the degree of opening of the relief valve can be controlled to remain at 0 (state completely closed). That is, the degree of opening of the relief valve when the degree of accelerator opening increases to the predetermined degree of accelerator opening is not limited to a small degree of opening such as 10%, but the opening degree can be 0. In this embodiment, for the opening degree of the relief valve 65, an opening degree of 0 and a small opening degree of 10% or similar are generally designated closed condition.

In addition, the accelerator opening degree is equal to 0 and the opening degree of the relief valve is set to a fully open state at time t0 of the initial state. Then, the degree of opening of the relief valve is set to a fully closed state when the degree of opening of the throttle becomes slightly greater than 0. However, the degree of opening of the relief valve can be set to a fully closed state when the accelerator opening degree is 0. In this case, since the exhaust gases flow into the turbine 60A from a state where the accelerator opening degree is equal at 0, the boost operation can be started at an early stage.

Next, the command to open and close the relief valve will be described with reference to the timing diagram in FIG. 4. FIG. 4 illustrates a transition when the relief valve 65 is opened from the degree of opening to 0 and is reduced to the degree of openness to 0.

A transition at the time of the opening of the relief valve 65 in the timing diagram corresponds to a transition of the degree of opening of the relief valve of FIG. 3 from time tl to time t3. In addition, the solid line illustrates a transition in this embodiment and the dotted line illustrates a transition in the comparative example.

In FIG. 4, since the degree of accelerator opening (not illustrated) is adjusted to be less than the second degree of accelerator opening in FIG. 3 at the instant t10 of the initial state, the degree d the opening of the relief valve is set to 0 (fully closed state).

Then, since the accelerator opening degree increases to the second accelerator opening degree of FIG. 3 at time t11, the opening valve relief degree is opened until degree of openness corresponding to the second degree of openness at once.

Then, at time tl2, the degree of accelerator opening is open in the fully open state and the degree of opening of the relief valve is also opened to a large degree of opening corresponding to the degree of accelerator opening.

Then, at time t13, the throttle opening degree is set to be low, and therefore the relief valve opening degree is also set to be low.

Then, since the accelerator opening degree decreases up to the second accelerator opening degree of FIG. 3 at time tl4, the degree of opening of the relief valve is set to 0 (state completely closed).

In this way, in this embodiment, the degree of minimal opening is omitted at the time of opening and closing of the relief valve 65. Accordingly, as it is possible to prevent a problem that the relief valve 65 has the minimum degree of opening, it is possible to prevent a collision noise called murmuring of the relief valve 65 in its minimum degree of opening.

As described above, according to this embodiment, the ECU 3 controls the relief valve 65 to an opening degree close to a closed state compared to a fully open state in the no-charge area in which the accelerator opening degree becomes equal to or less than the predetermined accelerator opening degree.

Consequently, when the relief valve 65 is controlled to an opening degree close to a closed state compared to a fully open state in the non-boost zone in which the accelerator opening degree is less than or equal at the predetermined accelerator opening degree, the exhaust gases can be supplied to the turbine 60A. Consequently, it is possible to actuate the turbine 60A in rotation without requiring the supercharging operation in the non-supercharging zone.

As a result, it is possible to obtain a desired boost pressure at an early stage when switching from the non-boost zone to the boost zone depending on an increase in the amount of pressure on the accelerator pedal. 22A, it is possible to improve the acceleration reactivity.

In addition, according to this embodiment, the ECU 3 controls the relief valve 65 until it reaches an opening degree close to a closed state compared to a fully open state so that the speed of rotation Turbocharger 60 becomes equal to or less than the predetermined turbine rotational speed to obtain the manifold pressure immediately before the boost operation begins in response to the predetermined throttle opening degree when the accelerator pedal 22A is inserted in the non-supercharging zone.

Consequently, the predetermined throttle opening degree is in a state immediately before the boost operation starts in the non-boost area and the turbine 60A can be rotated to a degree in which the operation boost is not performed in this state. Thus, it is possible to obtain a desired boost pressure at an early stage when switching to the boost zone.

In addition, since the turbine 60A can be rotated to a degree in which the boost operation is not performed in the non-boost area, it is possible to obtain a desired boost pressure at an early stage. moment of passage from the non-supercharging zone to the supercharging zone as a function of an increase in the amount of pressure on the accelerator pedal 22A and thus of improving the acceleration reactivity.

Furthermore, according to this embodiment, when the accelerator opening degree is the first accelerator opening degree as a predetermined accelerator opening degree, the ECU 3 controls the relief valve 65 up to the first degree of opening corresponding to the first degree of accelerator opening. In addition, when the accelerator opening degree is less than the second accelerator opening degree less than the first accelerator opening degree, the ECU 3 controls the relief valve 65 until it reaches a completely closed state. In addition, when the accelerator opening degree is greater than or equal to the second accelerator opening degree and is less than the first accelerator opening degree, the ECU 3 controls the opening degree of the relief valve 65 to reach the second degree of accelerator opening, less than the first degree of accelerator opening and corresponding to the degree of accelerator opening.

Consequently, since the degree of opening of the relief valve 65 is set to 0 and the relief valve 65 is set to a fully closed state in an area in which the degree of throttle opening is less than the second degree of throttle opening, it is possible to actively rotate the turbine 60A by the exhaust gases. For this reason, the driver can obtain a desired sensation of acceleration when the accelerator pedal 22A is depressed.

At the same time, since the degree of opening of the relief valve 65 is set to the second degree of opening corresponding to the degree of accelerator opening in an area of the second degree of accelerator opening or moreover, it is possible to improve the controllability of the relief valve 65.

In addition, since the relief valve 65 changes from the opening degree 0 to the second opening degree when the accelerator opening degree increases from 0 to the second or more accelerator opening degree, it is It is possible to prevent a problem that the relief valve 65 has the minimum degree of opening close to the fully closed state and to prevent the vibrations of the relief valve 65 in its minimum degree of opening.

In addition, according to this embodiment, the ECU 3 controls the relief valve 65 until it reaches an opening degree close to a closed state compared to a fully open state so that the speed of rotation of the turbine becomes homogeneous at the predetermined turbine speed of rotation to obtain the manifold pressure immediately before the supercharging operation begins in response to the predetermined degree of accelerator opening when the accelerator pedal 22A is depressed in the no overfeeding zone.

In this way, since the manifold pressure immediately before the start of the supercharging operation is kept homogeneous at the predetermined turbine rotation speed corresponding to the predetermined degree of accelerator opening in the non-supercharging zone, it is possible to obtain a desired boost pressure at an early stage when passing from the non-boost zone to the boost zone as a function of an increase in the amount of pressure on the accelerator pedal 22A and thereby improve responsiveness to acceleration.

In addition, according to this embodiment, when the accelerator pedal 22A is depressed in the non-boost zone, the ECU 3 controls the relief valve 65 to an opening degree close to a state closed by relative to a fully open state so that the degree of opening of the relief valve 65 corresponding to the predetermined degree of throttle opening increases as the engine speed increases.

Therefore, since the intake volume and the amount of exhaust gas increases as the engine speed increases, it is possible to prevent an excessive increase in the engine speed at the time of passage. from the non-overeating area to the overeating area.

Although embodiments of the present invention have been described, it is obvious that one skilled in the art could have made modifications without departing from the scope of the present invention. It is intended that all of these modifications and equivalents be included in the present invention.

Claims (5)

1. An engine control device for an engine, comprising a turbocharger pressurizing intake air using an engine exhaust gas, a bypass passage formed to bypass a turbine of the turbocharger so that a exhaust gas passes through it, a relief valve adjusting an amount of exhaust gas passing through the bypass passage, the engine control device comprising: a control unit performing a normal opening control to close the relief valve when an accelerator opening degree of an accelerator pedal is greater than a predetermined accelerator opening degree, in which the the control unit controls the relief valve to an opening degree close to a closed state compared to a fully open state in a non-overfeed zone of the accelerator opening degree equal to or less than the degree d '' predetermined throttle opening. 2. Engine control device according to claim 1, in which, when the accelerator pedal is depressed in the non-supercharging zone, the control unit controls the relief valve until it reaches a degree of opening close to a closed state relative to a fully open state so that a turbine rotation speed of the turbocharger becomes equal to or less than a predetermined turbine rotation speed to obtain a manifold pressure immediately before an operation boost only begins in response to the predetermined throttle opening degree. 3. Engine control device according to claim 1 or 2, wherein the control unit controls the relief valve until it reaches a first degree of opening corresponding to a first degree of accelerator opening when the accelerator opening degree is the first accelerator opening degree corresponding to the predetermined accelerator opening degree, in which the control unit controls the relief valve until it reaches a completely closed when the accelerator opening degree is less than a second accelerator opening degree less than the first accelerator opening degree, and in which the control unit controls the degree of opening of the valve discharge until it reaches a second degree of opening lower than the first degree of opening and corresponding to the degree of accelerator opening when the degree of o The throttle opening is greater than or equal to the second degree of accelerator opening and is less than the first degree of accelerator opening. 4. An engine control device according to claim 1 or 2, wherein, when the accelerator pedal is depressed in the non-boost area, the control unit controls the relief valve until it reaches a degree opening close to a closed state compared to a fully open state so that the turbine rotation speed becomes homogeneous with the predetermined turbine rotation speed to obtain a manifold pressure immediately before a boost operation begins in response to the predetermined throttle opening degree. 5. An engine control device according to claim 1 or 2, wherein, when the accelerator pedal is depressed in the non-boost area, the control unit controls the relief valve to an opening degree close to a closed state relative to a fully open state so that the degree of opening of the relief valve corresponding to the predetermined degree of throttle opening increases with increasing engine speed.