JP2000054894A - Controller for engine with turbosupercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of turbo lag by increasing an energy of exhaust gas in an early stage of acceleration. SOLUTION: This controller for an engine having a turbosupercharger 6 and a fuel injection valve 5 for directly injecting fuel into a combustion chamber is provided with an acceleration state detecting means and a fuel injection control means 19. The acceleration state detecting means comprises an acceleration opening sensor 16 for detecting an acceleration state of a vehicle, and the like. The fuel injection control means 19 controls the fuel injection valve 5 such that fuel is divisionally injected within a time range from an intake stroke to an ignition moment in an early stage of acceleration, while latter injection timing of the split injection is set to a period after the middle stage of a compression stroke.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a turbocharger,
The present invention relates to a control device for a turbocharged engine mounted on an automobile or the like having a fuel injection valve for directly injecting fuel into a combustion chamber.

[0002]

2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 7-119507, in a cylinder injection type spark ignition engine configured to perform uniform combustion by injecting fuel in an intake stroke, fuel diffusion is performed. At low speeds and low speeds,
By splitting the fuel during the intake stroke, the amount of fuel injected at one time is reduced and the injected fuel is sufficiently atomized and diffused by the intake air supplied until the next fuel injection timing, until the ignition timing. In order to prevent the generation of smoke, a good homogeneous mixture is formed by evaporating all the fuel in the entire cylinder.

[0003]

When the fuel is dividedly injected in the intake stroke when the engine is running at a low speed as described above, generation of smoke can be prevented. However, in the turbocharged engine equipped with a turbocharger, in order to prevent the occurrence of turbo lag during the first half of acceleration, the turbocharger's supercharging effect was increased by increasing the energy of the exhaust gas driving the turbine. Is desired to be obtained at an early stage, but in the prior art described in the above publication, the temperature of the exhaust gas cannot be increased, so that sufficient energy cannot be secured. For this reason, there is a problem that a turbo lag is generated in the first half of the acceleration period, and a supercharging effect of the turbocharger cannot be obtained, and the acceleration of the vehicle tends to be insufficient.

The present invention has been made in view of the above circumstances, and provides a control device for a turbocharged engine capable of preventing the occurrence of turbo lag by increasing the energy of exhaust gas in the first half of acceleration.

[0005]

The invention according to claim 1 is
In a control device of a turbocharged engine equipped with a turbocharger and a fuel injection valve for directly injecting fuel into a combustion chamber, acceleration state detection means for detecting an acceleration state of the vehicle,
Fuel injection control means is provided for injecting fuel in the range from the intake stroke to the ignition timing in the first half of the acceleration period, and for setting the injection timing in the latter period after the middle stage of the compression stroke.

[0006] According to the above configuration, control is performed in which fuel is divided and injected in the range from the intake stroke to the ignition timing in the first half of the acceleration period, and fuel in the second half is injected after the middle stage of the compression stroke. As a result, the exhaust gas temperature of the engine increases. As a result, the energy of the exhaust gas required to drive the turbine of the turbocharger is sufficiently secured, and the supercharging action of the turbocharger is quickly obtained, thereby improving the acceleration of the vehicle. become.

According to a second aspect of the present invention, in the control device for an engine with a turbocharger according to the first aspect of the present invention, the apparatus further comprises a load detecting means for detecting an engine load. It is configured to execute fuel split injection control in the previous period.

According to the above configuration, when the engine is easily accelerated from a low load region where turbo lag is likely to occur, the split injection control is executed, thereby preventing the occurrence of the turbo lag and supercharging the turbocharger. The action is obtained quickly, and the acceleration of the vehicle is effectively improved.

According to a third aspect of the present invention, in the control device for an engine with a turbocharger according to the first aspect of the present invention, there is provided a control system for the engine with a turbocharger, the system comprising: The fuel injection control in the first half of the acceleration is executed.

[0010] According to the above configuration, when the engine is accelerated from a low rotation region where a turbo lag is likely to occur, the split injection control is executed, thereby preventing the occurrence of the turbo lag and supercharging the turbocharger. The action is obtained quickly, and the acceleration of the vehicle is effectively improved.

According to a fourth aspect of the present invention, in the control apparatus for a direct injection type engine according to any one of the first to third aspects, the early fuel injection timing is set to the intake stroke during the first half of acceleration. It was done.

[0012] According to the above configuration, in the first half of the acceleration period, control for dividing and injecting fuel in the range from the intake stroke to the ignition timing is executed, and the early injection timing is set to the intake stroke. The fuel is effectively diffused and uniformly burned, and the engine output is sufficiently secured.

According to a fifth aspect of the present invention, in the control device for a turbocharged engine according to the fourth aspect, fuel is injected in an intake stroke at a later stage of acceleration.

According to the above configuration, by injecting all the fuel in the intake stroke in the latter stage of the acceleration, the fuel is effectively diffused and uniformly burned, and the engine output is sufficiently secured.

According to a sixth aspect of the present invention, in the control apparatus for a direct injection engine according to any one of the first to fifth aspects, the air-fuel ratio is set to 16 or less in the first half of acceleration.

According to the above configuration, the fuel injected in the first half of the acceleration forms a fuel-air mixture in a state close to the stoichiometric air-fuel ratio, so that the engine output is improved and it is necessary to drive the turbine of the turbocharger. The energy of the exhaust gas to be generated is sufficiently secured, and the acceleration of the vehicle is improved.

According to a seventh aspect of the present invention, in the control device for a turbocharged engine according to the fifth aspect, the air-fuel ratio is set to 16 or less in the latter period of the acceleration.

According to the above configuration, the fuel mixture injected at the latter stage of the acceleration forms a mixture in a state close to the stoichiometric air-fuel ratio, and the engine output is effectively improved.

According to an eighth aspect of the present invention, in the control device for a direct injection type engine according to any one of the first to seventh aspects, the ignition timing of the fuel is retarded from the MBT during the first half of acceleration. In addition to the above, there is provided an ignition timing control means for controlling the fuel ignition timing to return to the MBT in the latter period of the acceleration.

According to the above arrangement, the fuel ignition timing is changed to a more retarded side than the MBT in the first half of the acceleration.
The exhaust gas temperature is more effectively increased, and the engine output is secured by returning the fuel ignition timing to the MBT in the latter half of the acceleration.

According to a ninth aspect of the present invention, in the control apparatus for a turbocharged engine according to any one of the first to eighth aspects, the vehicle is accelerated while the engine is in an intake stroke injection operation range. Is detected, the early fuel injection timing is set to the intake stroke.

According to the above configuration, when acceleration of the vehicle is detected in a state where the engine is in the operation range of the intake stroke injection and engine output is required, the fuel is switched to the intake stroke in the first half of the acceleration. The injection is divided and injected in the latter part of the compression stroke, and the injected fuel on the early side is effectively diffused and uniformly burned, thereby ensuring sufficient engine output and increasing the exhaust gas temperature by the injected fuel on the latter side. However, sufficient energy of the exhaust gas required to drive the turbine of the turbocharger is secured.

According to a tenth aspect of the present invention, in the control device for an engine with a turbocharger according to any one of the first to eighth aspects, the vehicle is accelerated while the engine is in a compression stroke injection operation region. Is detected, the early fuel injection timing is set to the compression stroke.

According to the above configuration, when acceleration of the vehicle is detected in a state where the engine is in the operation range of the compression stroke injection and the engine output is not so demanded, the fuel is supplied in the compression stroke in the first half of the acceleration. Split injection is performed, and the energy of the exhaust gas is sufficiently ensured by these injected fuels, thereby improving the acceleration of the vehicle.

According to an eleventh aspect of the present invention, in the control apparatus for a direct injection engine according to the first aspect, the fuel is supplied to the intake stroke and the compression stroke during the initial stage of acceleration set to a period shorter than the initial period of acceleration. Injecting separately into the latter period,
Between the intake stroke and the latter half of the compression stroke, an amount of additional fuel corresponding to the increase in intake air is injected.

According to the above configuration, in the early stage of acceleration, the fuel injected in the intake stroke is effectively diffused and uniformly burned, and the engine output is ensured. Sufficient energy is provided to improve the acceleration of the vehicle.Additionally, additional fuel injected between the intake stroke and the latter part of the compression stroke secures an amount of fuel corresponding to the increase in intake air, and the engine output is increased. It will be secured enough.

According to a twelfth aspect of the present invention, in the control apparatus for a direct injection engine according to the eleventh aspect, the initial stage of acceleration is set within a period corresponding to one cycle of each cylinder of the engine from the start of acceleration. At the same time, the first period of acceleration is set within a period corresponding to a plurality of cycles of each cylinder of the engine from the start of acceleration.

According to the above configuration, fuel is divided and injected into an intake stroke and a latter half of a compression stroke from the start of acceleration to the initial stage of acceleration corresponding to one cycle of each cylinder of the engine. After the additional fuel is injected according to the increase in the intake air between the compression stroke and the second half of the compression stroke, the injection timing on the second half of the compression stroke is changed from the start of acceleration to the first half of acceleration corresponding to multiple cycles of each cylinder of the engine. The split injection of the fuel set after the middle period is executed.

According to a thirteenth aspect of the present invention, in the control apparatus for a direct injection engine according to the first aspect, when the engine is in a warm state, the injection timing of the latter half of the fuel is provided in the first half of the first half of the acceleration period. To the expansion stroke, and in the second half of the first half of the acceleration period,
The injection timing on the late stage is set after the middle stage of the compression stroke.

According to the above configuration, in the first half of the first half of the acceleration period, the fuel is injected into the combustion chamber of the engine in the warm state during the expansion stroke, so that the temperature of the exhaust gas of the engine rises effectively and the exhaust gas increases. The gas amount increases, and the energy of the exhaust gas required to drive the turbine of the turbocharger is sufficiently ensured, and the acceleration of the vehicle is improved.

According to a fourteenth aspect of the present invention, in the control apparatus for a direct injection type engine according to the first aspect, the first period of acceleration is:
It is set in a period from the acceleration start time to the middle of the increase in the intake air amount according to the increase in the accelerator opening.

According to the above-described structure, during the first half of the acceleration process in which the intake air amount increases in accordance with the increase in the accelerator opening from the start of the acceleration, the injection timing on the second half is set after the middle stage of the compression stroke. By performing the split injection, the exhaust gas temperature rises and the exhaust gas energy is sufficiently secured.

According to a fifteenth aspect of the present invention, in a control system for an engine with a turbocharger having a turbocharger and a fuel injection valve for directly injecting fuel into a combustion chamber, an acceleration state of the vehicle is detected. An acceleration state detecting means, an intake detecting means for detecting an intake air amount of the engine, and, when the vehicle is accelerated while the engine is in a compression stroke injection operation area when the engine is warm, In the early stage of acceleration with a small amount of air, fuel is divided and injected into a compression stroke and an expansion stroke, and in the second half of acceleration with a large amount of intake air,
The fuel injection control device controls the fuel to be divided into an intake stroke and a compression stroke so as to be injected.

According to the above configuration, during the acceleration period in which the intake air amount is small, the fuel is divided and injected into the compression stroke and the expansion stroke, so that the temperature of the exhaust gas of the engine rises and the exhaust gas is increased. In the latter period of the acceleration, in which the amount increases and the intake air amount is large, the fuel is divided and injected into the intake stroke and the compression stroke, so that the engine output is sufficiently secured and the turbine of the turbocharger is secured. , The energy of the exhaust gas required to drive the motor is sufficiently secured.

According to a sixteenth aspect of the present invention, in the control device for a turbocharged engine according to the fifteenth aspect, fuel is supplied to the first half of the compression stroke and the first half of the compression stroke during the middle period of acceleration between the first half period and the second half period. Injection is divided into the latter and later.

According to the above configuration, split injection control of fuel is performed which meets the demand for increasing the exhaust gas energy and the demand for the output of the engine, which change with the transition from the first half of acceleration to the second half of acceleration. Become.

[0037]

FIG. 1 shows an embodiment of a control device for a turbocharged engine according to the present invention. The turbocharged engine includes an in-cylinder injection type gasoline engine 1 mounted on an automobile, and an intake passage 2 and an exhaust passage 3 connected to the engine 1.
A spark plug 4 provided at the top of the combustion chamber of the engine body 1, a fuel injection valve 5 provided at the side of the combustion chamber,
And a turbocharger 6.

In the intake passage 2, an air flow sensor 7, a blower 8 of a turbocharger 6,
An intercooler 10 and an electric throttle composed of a motor-driven throttle valve 12 are provided, and a throttle sensor 11 is provided for the throttle valve 12. Further, a turbine 13 of the turbocharger 6 and a catalytic converter 14 are disposed in the exhaust passage 3.

In addition to the air flow sensor 7 and the throttle sensor 11,
Crank angle sensor 1 for detecting engine speed
5. Various sensors such as an accelerator opening sensor 16 and an engine water temperature sensor 17 are provided, and their detection signals are input to an engine control unit 18. The engine control unit 18 includes a fuel injection control unit 19 for controlling the fuel injection amount and the injection timing, and an ignition timing control unit 2 for controlling the ignition timing.
0 is provided.

The fuel injection control means 19 is set in advance based on the accelerator opening detected by the accelerator opening sensor 16 for detecting the accelerator opening and the engine speed detected by the crank angle sensor 15. The target torque of the engine from the map
Based on the target torque and the actual intake air amount detected by the air flow sensor 7, a target fuel injection amount is read from a preset map, and a control signal corresponding to the target fuel injection amount is transmitted to the fuel injection valve 5. Is configured to be output.

The fuel injection control means 20 is configured to control the fuel injection timing according to the operating state of the engine. That is, when starting the engine,
By promoting the vaporization and atomization of the fuel and improving the combustibility, in order to secure the startability of the engine, control is performed to collectively inject the fuel in the intake stroke to perform uniform combustion. I have.

Further, in the cold operation state in which the cooling water temperature of the engine is lower than the predetermined value, as shown in FIG. 2, when the engine is in the low-load low-speed region A, the air-fuel ratio is maintained at substantially the stoichiometric air-fuel ratio. The fuel is divided and injected into an intake stroke and a compression stroke. As a result, combustion is sequentially propagated from the vicinity of the ignition plug 4 to the periphery thereof in a state where a relatively rich air-fuel mixture exists near the ignition plug 4 and a relatively lean air-fuel mixture exists around the ignition plug 4. As a result, the so-called after-burning of fuel is promoted, the exhaust gas temperature rises, and the warm-up of the catalytic converter 14 is promoted. When the engine is in an operating region other than the low-load low-rotation region A, control is performed to perform a uniform combustion by injecting the fuel in a lump during the intake stroke.

In a warm operation state in which the engine coolant temperature is equal to or higher than a predetermined value, injection control at the time of deceleration such as performing a fuel cut is performed at the time of deceleration, and as shown in FIG. It is configured to execute fuel injection timing control corresponding to the operating state of the engine.
That is, when the engine is in the low-load low-speed range C in the warm operation state of the engine, stratified combustion is performed by injecting fuel in the compression stroke, and when the engine is in the high-load high-speed range D, the intake air It is configured to execute control for performing uniform combustion by collectively injecting fuel in the stroke.

The region B in FIG. 3 is a control region for performing supercharging promotion control when the vehicle is accelerating, and includes the compression stroke injection region C corresponding to the non-supercharging region in the low rotation speed region. is there.

Further, the fuel injection control means 20 is in a warm operation state in which the engine coolant temperature is equal to or higher than a predetermined value.
When the acceleration of the engine is detected in the control region B, the fuel is dividedly injected in a range from the intake stroke to the ignition timing in the first half of the acceleration, and the injection timing on the early side is set to the predetermined timing of the intake stroke. , And the late injection timing is set after the middle stage of the compression stroke.

In the latter period of the acceleration, fuel injection timing control corresponding to the operating range of the engine is executed, and in the low-load low-speed range C, the compression stroke injection is performed to perform stratified combustion. Operating areas other than the low load rotation area C,
That is, in the high-load and high-rotation region D, uniform combustion is performed by performing the intake stroke injection.

The ignition timing control means 20 controls the ignition timing such that the required minimum ignition advance (MBT) at which the maximum shaft torque can be obtained, in principle, according to the operating state of the engine. Have been.

The basic control operation of the control device for the engine with a turbocharger will be described with reference to the flowcharts shown in FIGS. When the control operation is started, first, each detection signal of the air flow sensor 7, the crank angle sensor 15, and the accelerator opening sensor 16 is read (step S1), and the accelerator opening detected by the accelerator opening sensor 16 is read. Then, based on the engine speed detected by the crank angle sensor 15, the target charging amount of intake air is calculated (step S2). Further, a value corresponding to the engine torque, that is, a value corresponding to the average effective pressure Pi, is calculated based on the target charging amount of intake air and the engine speed (step S3).

Next, based on the starter switch signal or the engine speed, etc., it is determined whether or not the current time is at the time of starting the engine (step S4). As a result of this judgment,
If it is confirmed that the engine is being started, the fuel injection timing is controlled so that the fuel is injected at once during the intake stroke (step S5).

If the determination in step S4 is NO and it is confirmed that the engine is not being started, the engine is in a warm state in which the engine has been warmed up based on the detection signal of the engine water temperature sensor. It is determined whether or not the engine is in the low-load low-speed range A (step S7). If NO is determined in step S7, the process proceeds to step S5, and the fuel injection timing is controlled so as to collectively inject fuel during the intake stroke. If YES is determined in the above step S7 and it is confirmed that the engine is in the low-load and low-speed region A, the fuel is divided into the intake stroke and the compression stroke and injected while keeping the stoichiometric air-fuel ratio. Next, the fuel injection amount and injection timing are controlled (step S8).

If YES is determined in the above step S6 and it is confirmed that the engine is in the warm running state, it is determined whether or not the engine is in the control region B (step S9), and NO is determined. If so, it is determined whether or not the vehicle is in a deceleration state according to the detection signal of the accelerator opening sensor 16 (step S10). If it is confirmed that the vehicle is in a decelerating state, injection control at the time of deceleration such as performing a fuel cut is executed (step S).
11).

If NO is determined in step S10 and it is confirmed that the vehicle is not in the deceleration state, the normal injection control for injecting fuel at the injection timing set at a time corresponding to the operation state of the engine is performed. (Step S
12).

If the result of the determination in step S9 is YES, that is, if it is confirmed that the engine is in the control area B, the vehicle is accelerated according to the detection signals from the accelerator opening sensor 16 and the air flow sensor 7, and the like. It is determined whether or not the vehicle is in the state (step S13). If the determination is NO, the process proceeds to step S10, where injection control during deceleration or normal injection control is executed.

The result of the determination in step S13 is YES.
If it is confirmed that the vehicle is in an accelerated state, it is determined whether or not the current time is in the first half of acceleration (step S1).
4). That is, is the acceleration first period set between the time when the vehicle enters the acceleration state according to the detection signal of the accelerator opening sensor 16 and the time corresponding to a plurality of cycles of each cylinder of the engine elapses? It is determined based on the count value of the timer or the like whether or not, and if YES is determined, split injection control is executed in which fuel is divided and injected into the intake stroke and the latter half of the compression stroke (step S1).
5). In this case, the air-fuel ratio is 16 or less, for example, approximately the stoichiometric air-fuel ratio.

If NO is determined in step S14 and it is confirmed that the present time is not the first half of acceleration but the second half of acceleration, it is determined whether or not the engine is in the low-load low-speed region C. (Step S16). If NO is determined in this step S16 and it is confirmed that the engine is in the high-load and high-speed rotation region D, control is performed to collectively inject fuel during the intake stroke (step S17). If it is determined as YES in the above step S16 and it is confirmed that the engine is in the low-load and low-rotation region C, control is performed to collectively inject fuel in the compression stroke (step S1).
8).

When the acceleration state detecting means comprising the accelerator opening sensor 16 confirms that the vehicle is in the accelerated state as described above, the fuel injection control means 19 controls the ignition from the intake stroke during the first half of acceleration. The fuel is divided and injected in the range up to the time period, and the later injection time is set after the middle stage of the compression stroke. In addition, the temperature of the exhaust gas of the engine can be increased, and the amount of the exhaust gas can be increased.

That is, as described above, the latter stage fuel is injected after the middle stage of the compression stroke, and this fuel can promote the so-called after-burning of the fuel. Therefore, as shown in FIG. The exhaust gas temperature can be effectively increased as compared with the case where all the fuel is injected in the intake stroke. Therefore, by sufficiently securing the energy of the exhaust gas required to drive the turbine 13 of the turbocharger 6, the turbocharger can be generated without generating a turbo lag as shown in FIG. The number of revolutions of the feeder 6 can be quickly increased to improve the acceleration of the vehicle.

Conventionally, as shown in FIG.
Immediately after the acceleration start time T1 at which the accelerator opening starts increasing, the operating state of the engine shifts from a stratified combustion region in which fuel is injected in the compression stroke to a uniform combustion region in which fuel is injected collectively in the intake stroke. Since the throttle valve 12 of the electric throttle is once closed, it gradually starts to increase in accordance with the accelerator opening, so that the intake air amount is as shown by the broken line in FIG. 6 (B). Then, it changes according to the opening degree of the throttle valve 12.

On the other hand, in the present embodiment, the fuel is dividedly injected in the range from the intake stroke to the ignition timing in the first half of the acceleration period, and the accelerator opening starts to increase in order to secure the acceleration torque. The opening degree of the throttle valve 12 and the decrease amount of the intake air amount after the acceleration start time T1 are reduced as compared with the conventional case. For this reason, in the first half of the acceleration, the amount of exhaust gas emitted can be increased more than before, thereby increasing the energy of the exhaust gas more than before, and as shown in FIG. The number of revolutions of the machine 6 can be quickly increased to improve the acceleration of the vehicle.

Further, in the above embodiment, when it is confirmed that the engine load detected by the load detecting means including the accelerator opening sensor 16 is in the low load region,
Since the split injection control of the fuel in the first half of the acceleration is performed, the split injection control is executed at the time of acceleration from a low load region of the engine where the turbo lag easily occurs, thereby preventing the occurrence of the turbo lag and Can be effectively improved.

Further, in the above embodiment, when it is confirmed that the engine rotation speed detected by the rotation speed detecting means including the crank angle sensor 15 is in the low rotation range, the fuel split injection control in the first half of the acceleration is performed. The split injection control is executed at the time of acceleration from a low rotation region of an engine in which turbo lag easily occurs, thereby preventing the occurrence of turbo lag and effectively improving the acceleration of the vehicle. be able to.

Further, as shown in the above embodiment, in the case where the fuel injection is executed in the range from the intake stroke to the ignition timing in the first half of the acceleration period, the injection timing on the early side of the fuel is changed in the first half of the acceleration period. When the setting is made, the fuel injected at the earlier injection timing can be effectively diffused and uniformly burned, so that the engine output can be sufficiently secured.

In the above embodiment, at the time of the transition from the first half of the acceleration to the second half of the acceleration, a transition is made to the injection control state according to the operating state of the engine, and the engine is operated in the low-load low-speed range C.
, A description has been given of a case in which the fuel is injected at one time in the intake stroke, and the fuel is injected at once in the compression stroke when the engine is in the high-load high-speed region D, as shown in FIG. As described above, when NO is determined in step S14 and it is confirmed that the current time is in the latter period of acceleration,
In step S21, the fuel may be injected all at once in the intake stroke. With this configuration, since all fuel is injected during the intake stroke in the latter stage of the acceleration, the fuel can be effectively diffused and uniformly burned, thereby sufficiently securing the engine output. be able to.

If it is determined YES in step S14 and it is confirmed that the current time is in the first half of the acceleration period, then in step S15, the fuel is divided into the intake stroke and the second half of the compression stroke. And the air-fuel ratio is 1
It is desirable to set it to 6 or less. In the case of such a configuration, the fuel injected in the first half of the acceleration forms a fuel-air mixture in a state close to the stoichiometric air-fuel ratio, so that the engine output can be improved and the turbine of the turbocharger 6 is driven. Therefore, it is possible to sufficiently secure the energy of the exhaust gas required for improving the acceleration of the vehicle.

Further, in step S21, even when the fuel is injected all at once in the intake stroke, the air-fuel ratio is set to 16
By setting as follows, it is necessary to form an air-fuel mixture in a state close to the stoichiometric air-fuel ratio by the fuel injected at the latter stage of acceleration, to improve the engine output, and to drive the turbine of the turbocharger 6. It is preferable that the exhaust gas is configured so that the energy of the exhaust gas can be sufficiently secured.

As shown in the embodiment shown in FIG.
In step S14, the ignition timing of the fuel is changed to a more retarded side than MBT in step S22, and in the latter period of acceleration in which step S14 is determined to be NO, the fuel The ignition timing may be returned to MBT.

In the case of the above configuration, in the first half of the acceleration, the ignition timing of the fuel is changed to a more retarded side than the MBT to promote the after-burning of the fuel, so that the exhaust gas temperature can be more effectively reduced. The engine output can be ensured by controlling the fuel ignition timing to return to the MBT so that the maximum shaft torque is obtained in the latter period of the acceleration, in addition to being able to raise the engine torque.

In the above-described embodiment, an example has been described in which the injection timing on the early side of fuel is always set to the intake stroke in the first half of the acceleration. However, the acceleration of the vehicle is detected in a state where the engine is in the operation range of the intake stroke injection. It may be configured to determine whether or not the fuel injection has been performed, and to change the injection timing on the early side of the fuel according to the determination result. That is, when acceleration of the vehicle is detected in a state where the engine is in the operation range of the intake stroke injection, fuel is divided and injected into the intake stroke and the latter half of the compression stroke in the first half of the acceleration, and the engine is injected. Is in the compression stroke injection operation range, and vehicle acceleration is detected,
The fuel may be divided and injected in the first half of the compression stroke and in the middle or later of the compression stroke.

With the above configuration, when the vehicle is detected to be in the state where the engine is in the operation range of the intake stroke injection and engine output is required, and the acceleration of the vehicle is detected, the injection fuel on the early side is discharged. It is possible to effectively diffuse and uniformly burn, thereby ensuring a sufficient engine output, and also to raise the exhaust gas temperature by the late injection fuel to drive the turbine of the turbocharger. The energy of the exhaust gas required for the above can be sufficiently secured.

When the engine is in the operation range of the compression stroke injection and the engine output is not so required,
If acceleration of the vehicle is detected, the fuel is divided and injected in the compression stroke in the first half of the acceleration, and the exhaust gas temperature can be effectively increased by the injected fuel. , The energy of the exhaust gas required for driving the turbocharger 6 is sufficiently secured, and the supercharging action of the turbocharger 6 can be quickly obtained to improve the acceleration of the vehicle.

When the fuel split injection control is performed in the first half of the acceleration period, the fuel is supplied to the intake stroke and the second half of the compression stroke in the initial stage of the acceleration set in a period corresponding to one cycle of each cylinder of the engine. And an additional amount of fuel may be injected between the intake stroke and the later stage of the compression stroke in a manner commensurate with the increase in intake air. In the case of such a configuration, in the initial stage of the acceleration,
The fuel injected during the intake stroke can be effectively diffused and uniformly burned, ensuring engine output, and the fuel injected during the compression stroke ensures sufficient exhaust gas energy to accelerate the vehicle. With the additional fuel injected between the intake stroke and the latter half of the compression stroke, an amount of fuel commensurate with the increase in intake air can be secured, and the engine output can be sufficiently secured.

When the engine is in a warm state, the injection timing on the second half side of the fuel is set to the expansion stroke in the first half of the first half of the acceleration, and the split injection control of the fuel in the first half of the acceleration is executed. May be configured. According to this configuration, at least in the first half of the first half of the acceleration period, the fuel is injected into the combustion chamber of the engine in the warm state during the expansion stroke, so that the temperature of the exhaust gas of the engine can be effectively increased, and the exhaust gas can be effectively increased. The amount of gas can be increased, whereby the energy of the exhaust gas required to drive the turbine of the turbocharger is sufficiently secured, and the acceleration of the vehicle is more effectively improved. it can.

Note that, instead of the above-described embodiment, in which the first half of the acceleration is set within a period corresponding to a plurality of cycles of each cylinder of the engine from the start of the acceleration, the acceleration is changed according to the detection values of the accelerator opening sensor 16 and the air flow meter 7. The vehicle may be configured to determine whether or not the vehicle is in a pre-acceleration state. That is, as shown in FIG. 6, a period from the acceleration start time T1 when the accelerator pedal is depressed to the time T2 when the intake air amount corresponding to the accelerator opening and the like also reaches a low predetermined value in the process of increasing the accelerator opening. May be set as the acceleration period.

According to the above configuration, in the process of increasing the intake air amount, the time T from the start of acceleration T1 at which the intake air amount reaches a constant value is set.
In the first half of the acceleration period up to the second stage, by executing split injection of fuel whose injection timing on the second half side is set after the middle stage of the compression stroke, the exhaust gas temperature can be raised and the exhaust gas energy can be sufficiently secured. .

Further, in the control device for an engine with a turbocharger provided with the turbocharger 6 and the fuel injection valve 5 for directly injecting fuel into the combustion chamber, the accelerator opening for detecting the acceleration state of the vehicle is provided. An acceleration state detecting means including a degree sensor 16; an intake detecting means including an air flow sensor 7 for detecting an intake air amount of the engine; and an engine in a state where the engine is in a compression stroke injection operation area when the engine is warm. When acceleration is detected, fuel is divided and injected into a compression stroke and an expansion stroke during the acceleration period in which the intake air amount is small, and in the acceleration period in which the intake air amount is large,
The fuel injection control means 19 for controlling the fuel to be divided and injected into the intake stroke and the compression stroke may be provided.

That is, when it is confirmed in step S6 in FIG. 4 that the engine is in the warm state, it is determined whether or not the engine is in the low-load low-speed range C as shown in FIG.
That is, it is determined whether or not the vehicle is in the compression stroke injection region (step S31). If YES is determined in step S13, and if it is confirmed in step S13 that the vehicle is in an acceleration state, the vehicle is accelerated. It is determined whether or not the vehicle is in the acceleration state in the first half (step S32).

If YES is determined in step S32, and it is confirmed that the current time is in the first half of the acceleration period, the divided injection control for dividing and injecting the fuel into the compression stroke and the second half of the expansion stroke is executed. (Step S3
3) Control is executed to change the ignition timing of the fuel to a more retarded side than the MBT (step S34).

If it is determined NO in step S32 and it is confirmed that the current time is not the first half of acceleration, it is determined whether or not the vehicle is in the middle acceleration period between the first half of acceleration and the second half of acceleration. Determine (step S35), YES
When it is determined that the fuel injection is divided into the intake stroke and the latter half of the compression stroke, the divided injection control is executed (step S36), and the ignition timing of the fuel is changed to a more retarded side than the MBT. The control is executed (Step S37).

If it is determined NO in step S35 and it is confirmed that the current time is in the latter period of acceleration, control is performed to collectively inject fuel during the intake stroke (step S38), and ignition of fuel is performed. The time is controlled to return to MBT (step S39).

If the fuel is divided and injected into the compression stroke and the expansion stroke during the early period of acceleration when the intake air amount is small as described above, the fuel can be reliably post-burned. Therefore, the temperature of the exhaust gas of the engine can be effectively increased, and the amount of the exhaust gas can be further increased. In the latter period of the acceleration in which the intake air amount is large, the fuel is divided and injected into the intake stroke and the compression stroke, so that the turbine of the turbocharger 6 can be used while sufficiently securing the engine output. The energy of the exhaust gas required for driving can be sufficiently secured.

Further, when the fuel is divided and injected into the first half of the compression stroke and the second half of the compression stroke in the middle period of acceleration between the first period of acceleration and the second period of acceleration as described above, There is an advantage that the split injection control of the fuel can be appropriately performed in accordance with the demand for increasing the exhaust gas energy and the demand for the output of the engine, which change with the shift from the first half to the middle half of the acceleration to the second half of the acceleration.

[0082]

As described above, the present invention relates to a control device for a turbocharged engine provided with a turbocharger and a fuel injection valve for directly injecting fuel into a combustion chamber.
Acceleration state detection means for detecting the acceleration state of the vehicle, and fuel injection for split injection of fuel in the range from the intake stroke to the ignition timing in the first half of acceleration and setting the injection timing in the latter half of the compression stroke in the middle and later stages of the compression stroke Because the control means is provided, in the first half of the acceleration, by ensuring sufficient energy of the exhaust gas required to drive the turbine of the turbocharger, without generating a turbo lag,
The speed of the turbocharger can be quickly increased to improve the acceleration of the vehicle.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a control device for a turbocharged engine according to the present invention.

FIG. 2 is a graph showing an operation range when the engine is cold.

FIG. 3 is a graph showing an operation range when the engine is warm.

FIG. 4 is a flowchart showing a first half of a control operation by the control device.

FIG. 5 is a flowchart showing a latter half of the control operation by the control device.

FIG. 6 is a time chart showing a control state of the engine with a turbocharger.

FIG. 7 is a flowchart showing another example of the latter half of the control operation by the control device.

FIG. 8 is a flowchart showing still another example of the latter half of the control operation by the control device.

[Explanation of symbols]

Reference Signs List 5 fuel injection valve 6 turbocharger 7 air flow sensor (intake detection means) 15 crank angle sensor (engine speed detection means) 16 accelerator opening sensor (acceleration state detection means / load detection means) 19 fuel injection control means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 41/02 325 F02D 41/02 325D 41/34 41/34 GH 43/00 301 43/00 301J 301B F02P 5/15 F02P 5/15 F (72) Inventor Keiji Araki 3-1, Fuchu-cho, Shinchu, Aki-gun, Hiroshima Mazda F-term (reference) 3G022 AA00 CA04 CA06 DA02 GA01 GA06 GA08 GA09 3G084 AA00 BA05 BA08 BA13 BA15 BA17 CA03 CA04 CA09 DA04 FA07 FA10 FA20 FA33 FA38 3G092 AA06 AA18 BA04 BA09 BB06 BB11 BB14 DB03 EA03 FA10 GA05 GA12 GA17 HA01Z HA06Z HE01Z HE03Z HE08Z HF08Z 3G301 HA01 HA04 HA06 HA11 JA01 MA03 MA01 PA03 MA01 PA03 LA01 PE01Z PE03Z PE08Z PF03Z

Claims (16)

[Claims] An acceleration state detecting means for detecting an acceleration state of a vehicle in a control device for an engine with a turbocharger, comprising a turbocharger and a fuel injection valve for directly injecting fuel into a combustion chamber. In the first half of acceleration, fuel injection control means for split injection of fuel in a range from an intake stroke to an ignition timing and setting a later injection timing after a middle stage of a compression stroke is provided. Control device for engine with a charger. 2. The control device for a turbocharged engine according to claim 1, further comprising a load detecting means for detecting an engine load, wherein when the acceleration is detected in a low load range of the engine, the divided fuel injection in the first half of the acceleration is performed. A control device for a turbocharged engine, wherein the control device is configured to execute control. 3. The control device for an engine with a turbocharger according to claim 1, further comprising a rotation speed detecting means for detecting an engine rotation speed. A control device for a turbocharged engine, wherein the control device is configured to execute split injection control. 4. The control device for a direct injection type engine according to claim 1, wherein:
A control device for a turbocharged engine, wherein an injection timing on an early side of fuel is set to an intake stroke. 5. The control device for a turbocharged engine according to claim 4, wherein fuel is injected in an intake stroke in a later stage of acceleration. . 6. The control device for a direct injection type engine according to claim 1, wherein during the acceleration period,
A control device for an engine with a turbocharger, wherein the air-fuel ratio is set to 16 or less. 7. The control device for an engine with a turbocharger according to claim 5, wherein the air-fuel ratio is set to 16 or less in a later stage of the acceleration. 8. The control apparatus for a direct injection type engine according to claim 1, wherein in the first period of acceleration,
An engine with a turbocharger, comprising: ignition timing control means for changing the ignition timing of fuel to a more retarded side than MBT and controlling the ignition timing of fuel to return to MBT at a later stage of acceleration. Control device. 9. The control device for a turbocharged engine according to claim 1, wherein the acceleration of the vehicle is detected in a state where the engine is in an operation range of an intake stroke injection. Is a control device for a turbocharged engine, wherein an injection timing on an early side of fuel is set to an intake stroke. 10. The control device for a turbocharged engine according to any one of claims 1 to 8, wherein when acceleration of the vehicle is detected in a state where the engine is in a compression stroke injection operation region. Is a control device for an engine with a turbocharger, wherein an early fuel injection timing is set in a compression stroke. 11. The control device for a direct injection engine according to claim 1, wherein the fuel is divided into an intake stroke and a latter half of a compression stroke in an early stage of acceleration set in a period shorter than the first stage of acceleration. A control device for an engine with a turbocharger, characterized in that it is configured to inject and inject an amount of additional fuel corresponding to an increased amount of intake air between an intake stroke and a latter half of a compression stroke. 12. The control device for a direct injection engine according to claim 11, wherein the initial stage of acceleration is set within a period corresponding to one cycle of each cylinder of the engine from the start of acceleration, and the initial period of acceleration is: A control device for a turbocharged engine, wherein the control is set within a period corresponding to a plurality of cycles of each cylinder of the engine from the start of acceleration. 13. The control device for a direct injection engine according to claim 1, wherein when the engine is in a warm state, the injection timing on the second half side of the fuel is set to the expansion stroke in the first half of the first half of the acceleration period. A control device for an engine with a turbocharger, wherein an injection timing of a latter period is set after a middle period of a compression stroke in a latter half of an acceleration first period. 14. The control device for a direct injection type engine according to claim 1, wherein the first half of the acceleration is set to a period from the start of the acceleration to a halfway point of the increase of the intake air amount according to the increase of the accelerator opening. A control device for an engine with a turbocharger, characterized in that: 15. A control device for an engine with a turbocharger, comprising a turbocharger and a fuel injection valve for directly injecting fuel into a combustion chamber, an acceleration state detection means for detecting an acceleration state of the vehicle, An intake detecting means for detecting an intake air amount of the engine; and, when the acceleration of the vehicle is detected in a state where the engine is in a compression stroke injection operation range when the engine is in a warm state, the above-described acceleration period in which the intake air amount is small. Fuel injection control means for controlling the fuel to be divided into a compression stroke and an expansion stroke and to be injected, and to control the fuel to be divided and injected into an intake stroke and a compression stroke in the latter half of the acceleration when the intake air amount is large. A control device for an engine with a turbocharger, comprising: 16. The control device for an engine with a turbocharger according to claim 15, wherein fuel is divided into a first half of a compression stroke and a second half of a compression stroke in a middle period of acceleration between the first stage of acceleration and the second period of acceleration. A control device for an engine with a turbocharger, characterized in that it is configured to inject fuel.