JP6988382B2 - Internal combustion engine control device - Google Patents

Description

The present invention relates to a control device for an internal combustion engine.

Conventionally, an in-cylinder injection type spark ignition internal combustion engine that guides fuel injected by a fuel injection device to the vicinity of a spark plug by using a tumble flow during stratified combustion is known (for example, Patent Document 1). In such an internal combustion engine, it is desirable that a combustible air-fuel mixture is present in the vicinity of the spark plug at the ignition timing regardless of the operating region. Therefore, in the internal combustion engine of Patent Document 1, the combustible air-fuel mixture is present in the vicinity of the spark plug at the ignition timing by changing the direction of injecting fuel depending on the operating region or adjusting the flow velocity of the airflow (tumble flow). And improved the ignitability.

Japanese Unexamined Patent Publication No. 2004-176604

By the way, some in-cylinder injection type spark ignition internal combustion engines inject fuel in a plurality of times. For example, there is an internal combustion engine that injects fuel in the intake stroke to form a homogeneous air-fuel mixture in the combustion chamber and injects fuel in the compression stroke to improve ignition stability.

However, the total amount of fuel injected in one combustion cycle (intake stroke → compression stroke → expansion stroke → exhaust stroke) is predetermined depending on the state of the internal combustion engine and the like. Therefore, when the split injection is performed as described above, the fuel injection amount (mass of the fuel) at one time is smaller than that when the split injection is not performed, and the momentum (penetration force or momentum) of the fuel jet is also reduced. ) Tends to weaken. As a result, it is conceivable that the fuel jet is overwhelmed by the momentum (also referred to as flow strength or momentum) of the airflow (tumble flow, etc.) in the combustion chamber, and the fuel cannot be properly placed (mixed) in the airflow. That is, there is a possibility that the fuel is dispersed near the wall surface of the cylinder and it is not possible to have an air-fuel mixture having a desired air-fuel ratio in the vicinity of the spark plug at the ignition timing.

In view of the above circumstances, it is a main object of the present invention to provide a control device for an internal combustion engine capable of allowing an air-fuel mixture having a desired air-fuel ratio to exist in the vicinity of a spark plug at the ignition timing.

In order to solve the above problems, the control device of the internal combustion engine is applied to an internal combustion engine provided with a fuel injection valve that directly injects fuel into the combustion chamber, and the fuel injection in one combustion cycle of the internal combustion engine is compressed by the intake stroke injection. An internal combustion engine control device that is divided into stroke injection and executed, and is a flow estimation unit that estimates the strength of the fluid flow in the combustion chamber in the compression stroke, and the fluid flow estimated by the flow estimation unit. It is a gist to include an adjusting unit for adjusting the penetrating force of the fuel jet in the compression stroke based on the strength of the above.

When the intake stroke injection and the compression stroke injection are performed in one combustion cycle of the internal combustion engine, the intake stroke injection forms a homogeneous air-fuel mixture in the cylinder, while the compression stroke injection provides suitable fuel ignition. It will be realized. However, when such split injection is performed, the injection amount in the compression stroke injection is small, so that the fuel jet is pushed away in the operating region where the inside of the cylinder has a high flow rate, and the fuel is successfully placed on the fluid (air flow) ( It is more likely that it cannot be mixed). That is, there is a high possibility that the fuel will be dispersed near the wall surface of the cylinder, and it will not be possible to have an air-fuel mixture having a desired air-fuel ratio in the vicinity of the spark plug at the ignition timing.

In this respect, in the above configuration, the strength of the fluid flow in the combustion chamber in the compression stroke is estimated, and the penetration force of the fuel jet in the compression stroke is adjusted based on the estimated strength of the fluid flow. Therefore, the strength of the fluid flow and the penetration force of the fuel jet can be adjusted so as to correspond to each other, and an air-fuel mixture having a desired air-fuel ratio can be preferably present in the vicinity of the spark plug at the ignition timing.

The figure which shows the outline of an engine control system. Schematic diagram showing the flow of fuel. A flowchart showing the control process. (A) and (b) are diagrams showing the relationship between the center position of the tumble flow and the fuel flow.

Hereinafter, embodiments will be described with reference to the drawings. In the present embodiment, an in-cylinder injection type multi-cylinder 4-cycle gasoline engine (internal combustion engine) mounted on a vehicle is targeted for control, and various actuators in the engine are electronically controlled. In each of the following embodiments, the parts that are the same or equal to each other are designated by the same reference numerals, and the description thereof will be used for the parts having the same reference numerals.

First, the overall schematic configuration of the engine control system will be described with reference to FIG. In the in-cylinder injection engine shown in FIG. 1 (hereinafter referred to as engine 10), an air flow meter 12 for detecting the amount of intake air is provided in the upstream portion of the intake pipe 11 as an intake passage. A throttle valve 14 whose opening degree is adjusted by a throttle actuator 13 such as a DC motor is provided on the downstream side of the air flow meter 12, and the opening degree (throttle opening degree) of the throttle valve 14 is built in the throttle actuator 13. It is detected by the throttle opening sensor. A surge tank 16 is provided on the downstream side of the throttle valve 14, and the surge tank 16 is provided with an intake pipe pressure sensor 17 for detecting the intake pipe pressure. An intake manifold 18 for introducing air into each cylinder of the engine 10 is connected to the surge tank 16.

At the outlet of the intake manifold 18 (the intake port of the engine 10 and the upstream side of the injector 21 described later), a partition plate 50 for vertically partitioning the intake passage is provided for each cylinder, and the upper passage 51 is provided by the partition plate 50. And the lower passage 52 are formed. A tumble control valve (TCV) 53 for opening and closing the lower passage 52 is arranged at the inlet of the lower passage 52 of each cylinder. The TCV53 is an airflow control valve that adjusts the strength of the airflow (strength of fluid flow) in the cylinder of the engine 10 by being electrically opened and closed by an actuator including a motor or the like. According to this TCV53, a vertical intake swirl flow (tumble flow) can be generated in the cylinder, and the swivel position can be adjusted.

The cylinder block 20 is provided with an electromagnetically driven injector 21 for each cylinder. Fuel is directly injected from the injector 21 into the combustion chamber 23 partitioned by the inner wall of the cylinder and the upper surface (top) of the piston 22. The injector 21 corresponds to a fuel injection valve for in-cylinder injection. High-pressure fuel is supplied to the injector 21 from a high-pressure fuel system having a high-pressure pump 26.

A brief description of the high pressure fuel system. This system has a low-pressure pump 25 that pumps fuel in the fuel tank 24, a high-pressure pump 26 that increases the pressure of the low-pressure fuel pumped by the low-pressure pump 25, and a pressure accumulator chamber that stores the high-pressure fuel discharged from the high-pressure pump 26. It has a delivery pipe 27 constituting the above. Injectors 21 of each cylinder are connected to the delivery pipe 27. The high-pressure fuel that has been increased in pressure by the high-pressure pump 26 and stored in the delivery pipe 27 is injected into the combustion chamber 23 (inside the cylinder) by the injector 21. Further, the high-pressure fuel pipe 28 or the delivery pipe 27 connecting the high-pressure pump 26 and the delivery pipe 27 is provided with a fuel pressure sensor 29 for detecting the fuel pressure (fuel pressure).

The high-pressure pump 26 is a mechanical fuel pump and is driven by the rotation of the camshaft of the engine 10. The fuel discharge amount of the high-pressure pump 26 is controlled by the opening degree of the fuel pressure control valve 26a provided in the high-pressure pump 26, and the fuel pressure in the delivery pipe 27 is increased to, for example, about 20 MPa at the maximum. The fuel pressure control valve 26a comprises a suction metering valve that adjusts the amount of fuel sucked into the fuel pressurizing chamber of the high-pressure pump 26, or a discharge metering valve that regulates the amount of fuel discharged from the fuel pressurizing chamber. The fuel pressure in the delivery pipe 27 is variably controlled by adjusting the opening degree of the fuel pressure control valve 26a.

Further, the intake port and the exhaust port of the engine 10 are provided with an intake valve 31 and an exhaust valve 32 that open and close according to the rotation of a camshaft (not shown), respectively. The intake air is introduced into the combustion chamber 23 by the opening operation of the intake valve 31, and the exhaust gas after combustion is discharged to the exhaust pipe 33 by the opening operation of the exhaust valve 32. The intake valve 31 and the exhaust valve 32 are provided with variable valve mechanisms 31A and 32A that change the opening / closing timing of each of the valves. The variable valve mechanisms 31A and 32A adjust the relative rotation phase between the crank shaft and the intake cam shaft of the engine 10, and can adjust the phase to the advance angle side and the retard angle side with respect to a predetermined reference position. It has become. As the variable valve mechanisms 31A and 32A, hydraulically driven or electrically driven variable valve mechanisms are used.

A spark plug 34 is attached to each cylinder of the cylinder head of the engine 10, and a high voltage is applied to the spark plug 34 at a desired ignition timing through an ignition coil or the like (not shown). By applying this high voltage, a spark discharge is generated between the facing electrodes of each spark plug 34, and the fuel is ignited in the combustion chamber 23 to be used for combustion.

The exhaust pipe 33 is provided with a purification device 35 for purifying the exhaust gas. Examples of the purification device 35 include a selective reduction catalyst converter (SCR catalyst converter), a NOx storage reduction catalyst, and a three-way catalyst. Further, on the upstream side of the purification device 35 in the exhaust pipe 33, an air-fuel ratio sensor 36 that detects the air-fuel ratio of the air-fuel mixture with the exhaust as the detection target is provided.

In addition, the cylinder block 20 outputs a water temperature sensor 37 that detects the engine water temperature (corresponding to the engine temperature) and a rectangular crank angle signal for each predetermined crank angle of the engine 10 (for example, in a 10 ° CA cycle). A crank angle sensor 38 is attached. Although not shown, the exhaust pipe 33 is provided with a NOx sensor, a PM sensor, and the like.

The outputs of the various sensors described above are input to an electronic control unit (hereinafter referred to as ECU 40) as a control device that controls engine control. The ECU 40 includes a microcomputer including a CPU, ROM, RAM, etc., and controls the fuel injection amount of the injector 21 according to the engine operating state by executing various control programs stored in the ROM. It also controls the ignition timing of the spark plug 34 and controls the fuel pressure.

For example, the ECU 40 controls the drive of the high-pressure pump 26 to perform fuel pressure control so as to maintain the fuel pressure in the delivery pipe 27, that is, the injection pressure at a desired pressure. Specifically, the ECU 40 sets a target fuel pressure and performs fuel pressure feedback control based on the deviation between the target fuel pressure and the actual fuel pressure detected by the fuel pressure sensor 29.

Here, the basic control of fuel injection will be described. The ECU 40 uses the engine load (for example, the intake air amount) and the engine rotation speed as parameters, and calculates the basic injection amount based on these parameters. Then, the ECU 40 appropriately performs water temperature correction, air-fuel ratio correction, and the like with respect to the basic injection amount, and calculates the final fuel injection amount (total injection amount). Then, the ECU 40 generates an injection signal at the injection timing, and drives and controls the injector 21 by the injection signal.

Then, in the present embodiment, fuel is injected in the intake stroke and the compression stroke, respectively. That is, the ECU 40 injects fuel in the intake stroke (by the intake stroke injection) to form a homogeneous air-fuel mixture in the combustion chamber 23. Then, the ECU 40 injects fuel in the compression stroke (by the compression stroke injection) to improve the ignition stability.

By the way, in order to suitably improve the ignition stability, it is necessary to execute the compression stroke injection so that the air-fuel mixture having a desired air-fuel ratio exists in the vicinity of the spark plug 34 at the ignition timing. However, when the split injection is performed, the injection amount injected in the compression stroke tends to be smaller and the penetration force of the fuel jet tends to be weaker than when the split injection is not performed.

Therefore, in the compression stroke, the strength of the fluid flow in the combustion chamber 23 and the penetration force of the fuel jet may not correspond to each other. In this case, as shown in FIG. 2, in the compression stroke, there is a high possibility that the fuel jet is overwhelmed by the momentum of the fluid flow and the fuel cannot be properly placed (mixed) on the fluid (air flow). That is, there is a high possibility that the fuel is dispersed in the vicinity of the wall surface of the combustion chamber 23, and the air-fuel mixture having a desired air-fuel ratio cannot be suitably present in the vicinity of the spark plug 34 at the ignition timing. Therefore, in order to suitably exist the air-fuel mixture having a desired air-fuel ratio in the vicinity of the spark plug 34 at the ignition timing, the strength of the fluid flow in the combustion chamber 23 in the compression stroke (hereinafter, simply referred to as the strength of the compression flow). It is necessary to inject fuel with a penetrating force according to the strength of the compression flow by guessing (shown).

Therefore, the ECU 40 executes the following control processes related to injection control in order to preferably allow an air-fuel mixture having a desired air-fuel ratio in the vicinity of the spark plug 34 at the ignition timing. This control process is executed by the ECU 40 every one combustion cycle.

As shown in FIG. 3, the ECU 40 calculates the basic base value for calculating the strength of the compression flow and the turning position of the vortex generated in the combustion chamber 23 based on the engine operating state (step). S101). The base value is a value corresponding to the strength of the fluid flow generated in the combustion chamber 23 when it is assumed that the airflow control by the TCV53 is not performed, and is a value calculated by the engine operating state. This base value is also a basic value for determining how to control when executing the airflow control described later.

The swirling position of the vortex flow generated in the combustion chamber 23 is specifically the center position K of the tumble flow. The center position K of the tumble flow estimated in step S101 is the center position K of the tumble flow estimated based on the engine operating state, assuming that the airflow control by the TCV53 is not performed.

In step S101, the ECU 40 calculates the base value and the center position K of the tumble flow based on the engine rotation speed and the engine load. Specifically, the base value according to the engine rotation speed and the engine load, and the center position K of the tumble flow according to the engine rotation speed and the engine load are acquired in advance by a conformance test and stored as a map. Then, the base value and the center position K of the tumble flow are estimated (calculated) using the map. By step S101, the ECU 40 is provided with a function as a position estimation unit for estimating the swirling position of the vortex flow (center position K of the tumble flow) in the combustion chamber 23.

Next, the ECU 40 calculates a target fuel pressure as a basis for calculating the final fuel pressure, and also calculates a basic injection amount in each stroke (step S102). In step S102, the ECU 40 calculates a target fuel pressure as a basis for calculating the final fuel pressure based on the engine operating state (engine rotation speed and engine load).

Further, in step S102, the ECU 40 calculates the total injection amount based on the engine operating state (engine rotation speed and engine load), divides the total injection amount, and determines each basic injection amount in the intake stroke and the compression stroke. do. The basic injection amount in each stroke is defined as a range of injection amounts that can be injected in each stroke, and is configured to be divided within each range. The range of the injection amount that can be injected in each stroke is set by a conformity test or the like based on the viewpoint of emission requirement and ignition stability.

Next, the ECU 40 determines whether or not the base value calculated in step S101 is equal to or higher than a predetermined threshold value Th (step S103). When the base value is equal to or higher than a predetermined threshold value Th (step S103: YES), the ECU 40 performs airflow control so that the center position K of the tumble flow is lower than the fuel injection position (direction). (Step S104). Specifically, the intake air flow is controlled by adjusting the opening degree of the TCV53 so that the center position K of the tumble flow is adjusted to be lower than the fuel injection position (direction). The control amount of TCV53 is determined based on the base value estimated in step S101, the center position K of the tumble flow, and the like.

As shown in FIG. 4A, when the center position K of the tumble flow is below the fuel injection position (direction), it goes around the inside of the combustion chamber 23 and reaches the vicinity of the spark plug 34. The fuel injection direction is the axial direction of the injector 21. Therefore, when the fluid flow is strong and the speed of the tumble flow in the combustion chamber 23 is high, the center position K is set below the fuel injection position, and the distance that the fuel (air-fuel mixture) moves on the tumble flow is set. Lengthen. Thereby, the air-fuel mixture can be suitably present in the vicinity of the spark plug 34 at the ignition timing.

On the other hand, when the base value is smaller than the predetermined threshold value Th (step S103: NO), the ECU 40 sets the intake flow so that the estimated center position K of the tumble flow is above the fuel injection position. Control (step S105). The control amount of TCV53 is determined in the same manner as in step S104.

When the center position K of the tumble flow is above the fuel injection position (direction) (when the fuel injection position is below the center position K), combustion is as shown in FIG. 4 (b). It reaches the vicinity of the spark plug 34 before going around the inside of the chamber 23. Therefore, when the fluid flow is weak and the speed of the tumble flow in the combustion chamber 23 is slow, the center position K is set above the fuel injection position, and the distance that the fuel (air-fuel mixture) moves on the tumble flow is shortened. do. Thereby, the air-fuel mixture can be suitably present in the vicinity of the spark plug 34 at the ignition timing.

By the way, when the airflow control by TCV53 is carried out in steps S104 and S105, it also affects the strength of the compression flow. That is, since the strength of the compressed flow is considered to depend on the intake flow after the airflow control, it is necessary to correct the base value (strength estimated in step S101).

Therefore, the ECU 40 corrects the base value and estimates the strength of the compression flow (step S106). That is, in step S106, the strength of the compressed flow is estimated when the airflow control (control of the intake flow) based on steps S104 and 105 is performed.

Specifically, the correction amount of the base value is acquired in advance by the conformity test based on the control amount of the TCV53, and the map is stored in the map. Then, the ECU 40 corrects the base value based on the control amount of the TCV53 determined in steps S104 and S105 with reference to the map, and estimates the strength of the compression flow.

By executing the processes of steps S101 and S106, the ECU 40 estimates the strength of the compression flow based on the engine operating state (engine rotation speed and engine load) and the control state of the TCV53. That is, the ECU 40 calculates the base value based on the engine operating state, and corrects the calculated base value based on the control state of the TCV 53 to estimate the strength of the compression flow. By executing the processes of steps S101 and S106, the ECU 40 is provided with a function as a flow estimation unit 41 for estimating the strength of the fluid flow in the combustion chamber 23 in the compression stroke.

Next, the ECU 40 calculates the penetration force (required penetration force) of the fuel jet required in the compression stroke based on the strength of the compression flow estimated in step S106 (step S107).

Then, the ECU 40 changes (corrects) the basic injection amount in the compression stroke so that the penetration force of the fuel jet in the compression stroke satisfies the required penetration force, determines the injection amount in the compression stroke injection, and determines the injection amount in the compression stroke. The penetration force of the fuel jet is adjusted (step S108). Specifically, when the strength of the compression flow is large, the ECU 40 adjusts the penetration force by increasing the injection amount in the compression stroke injection as compared with the case where the compression flow strength is small. When the injection amount in the compression stroke is increased, it is necessary to reduce the injection amount in the intake stroke accordingly.

Further, as described above, since the range of the injection amount that can be injected in each stroke is predetermined, the injection amount in the compression stroke is determined (changed) so that the injection amount in each stroke falls within each range. )do. Therefore, when the injection amount cannot be determined so that the penetration force of the fuel jet in the compression stroke satisfies the required penetration force within the range of the injection amount in the compression stroke (when the required penetration force is not satisfied). In the compression stroke, the upper limit value within the range that can be injected is determined as the injection amount.

Next, the ECU 40 adjusts the penetration force by changing the fuel pressure (injection pressure) so that the penetration force of the fuel jet in the compression stroke satisfies the required penetration force (step S109). For example, when the strength of the compression flow is large, the ECU 40 adjusts the penetration force by increasing the fuel pressure injected from the injector 21 as compared with the case where the strength of the compression flow is small. In step S109, the fuel pressure (injection pressure) is changed so that the penetration force of the fuel jet in the compression stroke satisfies the required penetration force on the premise that the fuel is injected at the injection amount set in step S108. ..

Specifically, the ECU 40 is the basis calculated in step S102 so that the penetration force of the fuel jet in the compression stroke satisfies the required penetration force when the fuel is injected at the injection amount set in step S108. Correct (change) the target fuel pressure. Then, the fuel pressure feedback control is performed based on the deviation between the corrected target fuel pressure and the actual fuel pressure detected by the fuel pressure sensor 29. Then, the control process is terminated.

By executing the processes of steps S108 and S109, the ECU 40 has a function as an adjusting unit 42 for adjusting the penetration force of the fuel jet in the compression stroke based on the strength of the compression flow. Further, by executing the process of step S108, the ECU 40 is provided with a function as a first adjusting unit for adjusting the penetration force by changing the injection amount in the compression stroke injection. Further, by executing the process of step S109, the ECU 40 has a function as a second adjusting unit for adjusting the penetration force by changing the injection pressure which is the pressure of the fuel injected from the injector 21. Become.

Since step S108 is executed before step S109, when the penetration force is adjusted based on the strength of the fluid flow, the first adjustment unit of the first adjustment unit and the second adjustment unit is used. It can be said that the adjustment is given priority.

Further, in step S108, if the injection amount cannot be determined (changed) so that the penetration force of the fuel jet in the compression stroke satisfies the required penetration force within the range of the injection amount in the compression stroke, compression is performed. The upper limit value within the range that can be injected in the stroke is determined as the injection amount. Therefore, when the adjustment by the injection amount is performed, the ECU 40 performs the adjustment by the injection pressure based on the fact that the adjustment amount reaches a predetermined upper limit.

According to the present embodiment described in detail above, the following excellent effects can be obtained.

When the intake stroke injection and the compression stroke injection are performed in one combustion cycle, the intake stroke injection forms a homogeneous air-fuel mixture in the cylinder, while the compression stroke injection realizes suitable fuel ignition. .. However, when such split injection is performed, the injection amount in the compression stroke injection is small, so that the fuel jet is pushed away in a state where the inside of the combustion chamber 23 has a high flow rate, and the fuel is successfully placed on the fluid (air flow). There is a high possibility that it cannot be (mixed). That is, it is highly possible that the fuel is dispersed in the vicinity of the wall surface of the combustion chamber 23, and the air-fuel mixture having a desired air-fuel ratio cannot be present in the vicinity of the spark plug 34 at the ignition timing.

In this regard, in the above configuration, the strength of the fluid flow in the combustion chamber 23 in the compression stroke is estimated, and the penetration force of the fuel jet in the compression stroke is based on the estimated strength of the fluid flow (compression flow). It will be adjusted. Therefore, the penetration force of the fuel jet can be adjusted so as to correspond to the strength of the compression flow, and the air-fuel ratio having a desired air-fuel ratio can be suitably present in the vicinity of the spark plug 34 at the ignition timing. ..

It is conceivable that increasing the fuel injection amount will increase the penetration force of the fuel jet. Utilizing this, when the strength of the fluid flow in the combustion chamber 23 is large, the injection amount in the compression stroke is increased as compared with the case where the strength is small. As a result, even when the strength of the fluid flow (compressed flow) in the combustion chamber 23 is large, the air-fuel mixture having a desired air-fuel ratio can be suitably present in the vicinity of the spark plug 34 at the ignition timing. can.

It is conceivable that increasing the injection pressure (fuel pressure) of the injector 21 increases the penetration force of the fuel jet. Utilizing this, when the strength of the fluid flow (compressive flow) in the combustion chamber 23 is large, the injection pressure is increased as compared with the case where the strength is small. As a result, even under a state where the strength of the fluid flow in the combustion chamber 23 is large, an air-fuel mixture having a desired air-fuel ratio can be suitably present in the vicinity of the spark plug 34 at the ignition timing.

In the above configuration, the penetration force is adjusted by changing the injection amount and the injection pressure. Therefore, even if there is a limit to the range that can be set in either one or both, the degree of freedom of adjustment can be improved.

When the injection pressure (fuel pressure) is increased, the output of the engine 10 is used, so that the fuel consumption is deteriorated. Therefore, when the penetration force is adjusted according to the required penetration force, the influence on the fuel consumption is reduced by preferentially changing the injection amount. Further, in the above embodiment, the ECU 40 changes the injection pressure (fuel pressure) in step S109 when the injection amount reaches a predetermined upper limit. Therefore, the change in fuel pressure can be minimized, and the influence on fuel efficiency can be minimized.

Airflow control (intake flow control) is performed by the TCV53 as an airflow control valve in order to adjust the center position K of the tumble flow so that the air-fuel mixture is suitably present in the vicinity of the spark plug 34 at the ignition timing. Specifically, when the base value is strong, the opening degree of the TCV53 is adjusted so that the center position K of the tumble flow is lower than the fuel injection position. On the other hand, when the base value is weak, the opening degree of the TCV53 is adjusted so that the center position K of the tumble flow is above the fuel injection position.

When such intake flow control is performed, it is difficult to estimate the strength of the fluid flow in the compression stroke only from the engine operating state. Therefore, the ECU 40 has decided to estimate the strength of the fluid flow in the compression stroke based on the engine operating state and the control state of the TCV53. More specifically, the ECU 40 estimates the base value based on the engine operating state, corrects the base value based on the control amount of the TCV53, and estimates the strength of the compression flow. Thereby, even if the intake flow is controlled by the TCV53, the strength of the fluid flow in the compression stroke can be appropriately estimated.

(Other embodiments)
The present invention is not limited to the above embodiment, and may be implemented as follows, for example.

In the above embodiment, the center position K of the tumble flow is adjusted by adjusting the opening degree of the TCV53, but the profile of the intake valve 31 (valve opening timing, lift amount, etc.) is adjusted to adjust the center position K of the tumble flow. You may. In this case, the intake valve 31 corresponds to the airflow control valve.

In the above embodiment, the center position K of the tumble flow is adjusted, but the injection direction of the injector 21 can be changed instead of the air flow control or together with the air flow control, and the injection is performed according to the center position K of the tumble flow. You may change the direction. This eliminates the need to adjust the center position K of the tumble flow by airflow control. In order to change the injection direction of the injector 21, for example, the injector 21 can be rotatably configured. Further, for example, a plurality of injectors 21 having different injection angles may be provided, and the injector 21 to be injected may be selected according to the injection angle. Further, the injector 21 may be provided with a plurality of injection holes having different injection angles, and the injection holes may be selected.

In the above embodiment, the ECU 40 may adjust the penetration force based on the strength of the compression flow and the center position K of the tumble flow. For example, if the strength of the compression flow is equal to or higher than the threshold value and the center position of the tumble flow is below the fuel injection position, the penetration force of the fuel jet in the compression stroke may be adjusted to be large. good. On the other hand, if the strength of the compression flow is smaller than the threshold value or the center position of the tumble flow is above the fuel injection position, the penetration force of the fuel jet in the compression stroke may be adjusted to be small. .. Thereby, the air-fuel mixture having a desired air-fuel ratio can be more preferably present in the vicinity of the spark plug 34 at the ignition timing.

In the above embodiment, both the injection pressure and the injection amount can be changed when adjusting the penetration force of the fuel jet in the compression stroke, but only one of them may be changeable.

In the above embodiment, when adjusting the penetration force of the fuel jet in the compression stroke, the injection amount is preferentially changed, but the injection pressure (fuel pressure) may be preferentially changed.

In the above embodiment, it is not necessary to adjust the center position K of the tumble flow.

10 ... engine, 21 ... injector, 23 ... combustion chamber, 40 ... ECU, 41 ... flow estimation unit, 42 ... adjustment unit.

Claims (2)

It is applied to an internal combustion engine (10) provided with a fuel injection valve (21) that directly injects fuel into the combustion chamber (23), and the fuel injection in one combustion cycle of the internal combustion engine is divided into an intake stroke injection and a compression stroke injection. In the control device (40) of the internal combustion engine that is divided and executed,
A flow estimation unit (41) that estimates the strength of the fluid flow in the combustion chamber in the compression stroke, and
An adjusting unit (42) that adjusts the penetration force of the fuel jet in the compression stroke based on the strength of the fluid flow estimated by the flow estimation unit.
Equipped with
The adjustment unit
The first adjusting unit (40) that adjusts the penetration force by changing the injection amount in the compression stroke injection,
It is provided with a second adjusting unit (40) that adjusts the penetration force by changing the injection pressure, which is the pressure of the fuel injected from the fuel injection valve.
A control device for an internal combustion engine that preferentially performs adjustment by the first adjusting unit among the first adjusting unit and the second adjusting unit when the penetration force is adjusted based on the strength of the fluid flow. .. The adjusting unit is based on the fact that the adjustment amount reaches a predetermined upper limit when the adjustment by the first adjusting unit is performed among the first adjusting unit and the second adjusting unit. The control device for an internal combustion engine according to claim 1 , wherein the adjustment is performed by the second adjusting unit.

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