JP2019085914A - Control device for internal combustion engine - Google Patents

Abstract

A control device for an internal combustion engine is provided that allows a mixture having a desired air-fuel ratio to be present near an ignition plug at an ignition timing. A control device (40) is applied to an internal combustion engine (10) provided with a fuel injection valve (21) for directly injecting fuel into a combustion chamber (23), and performs fuel injection in one combustion cycle with intake air. The injection is divided into stroke injection and compression stroke injection. The control device includes: a flow estimating unit (41) for estimating the strength of the fluid flow in the combustion chamber in the compression stroke; and a penetration of the fuel jet in the compression stroke based on the fluid flow intensity estimated by the flow estimating unit. An adjusting unit (42) for adjusting the force. [Selection diagram] Fig. 1

Description

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

  2. Description of the Related Art Conventionally, there has been known an in-cylinder injection spark ignition internal combustion engine that guides fuel injected by a fuel injection device near a spark plug using tumble flow during stratified combustion (for example, Patent Document 1). In such an internal combustion engine, it is desirable that a combustible mixture is present in the vicinity of the spark plug at the ignition timing regardless of the operating range. Therefore, in the internal combustion engine of Patent Document 1, the combustible mixture is present in the vicinity of the spark plug at the ignition timing by changing the fuel injection direction depending on the operating region or adjusting the flow velocity of the air flow (tumble flow). To improve the ignitability.

JP, 2004-176604, A

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

  However, the total amount of fuel injected in one combustion cycle (intake stroke → compression stroke → expansion stroke → exhaust stroke) is determined in advance by the state of the internal combustion engine or the like. For this reason, when performing split injection as described above, the amount of fuel injection (fuel mass) per time is smaller than when not performing split injection, and the force of the fuel jet (penetration force or momentum) ) Tend to be weak. As a result, it is conceivable that the fuel jet flow is pushed against the momentum (also referred to as flow intensity or momentum) of the air flow (such as tumble flow) in the combustion chamber and the fuel can not be well loaded (mixed) in the air flow. That is, there is a possibility that the fuel may be dispersed in the vicinity of the cylinder wall surface and the air-fuel mixture having a desired air-fuel ratio in the vicinity of the spark plug can not be present at the ignition timing.

  SUMMARY OF THE INVENTION In view of the above situation, the present invention has as its main object to provide a control device of an internal combustion engine capable of causing an air-fuel mixture having a desired air-fuel ratio in the vicinity of a spark plug at the ignition timing.

  In order to solve the above problems, a control device for an internal combustion engine is applied to an internal combustion engine provided with a fuel injection valve that directly injects fuel into a combustion chamber, and fuel injection in one combustion cycle of the internal combustion engine is reduced by intake stroke injection and compression. A control device for an internal combustion engine that is divided into stroke injection and executed, the flow estimation unit estimating the strength of fluid flow in the combustion chamber in a compression stroke, and the fluid flow estimated by the flow estimation unit And a controller configured to adjust the penetration of the fuel jet in the compression stroke based on the strength of the above.

  When intake stroke injection and compression stroke injection are respectively performed in one combustion cycle of the internal combustion engine, homogeneous mixture is formed in the cylinder by the intake stroke injection, while fuel ignition is preferably performed by the compression stroke injection. To be realized. However, at the time of performing such split injection, the amount of injection in compression stroke injection decreases, so the fuel jet flow is pushed over in the operation region where the inside of the cylinder becomes highly fluid, and the fuel (airstream) is loaded successfully ( There is a high possibility that it can not be mixed). That is, the fuel is dispersed near the cylinder wall surface, and there is a high possibility that the air-fuel mixture having a desired air-fuel ratio can not be present near the spark plug at the ignition timing.

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

The figure which shows the outline of an engine control system. The schematic diagram which shows the flow of a fuel. The flowchart which shows control processing. (A) And (b) is a figure which shows the relationship between the center position of tumble flow, and the flow of a fuel.

  Hereinafter, embodiments will be described based on the drawings. In this embodiment, an in-cylinder injection multi-cylinder 4-cycle gasoline engine (internal combustion engine) mounted on a vehicle is to be controlled, and electronic control of various actuators in the engine is performed. In addition, in the following each embodiment, the same code | symbol is attached | subjected to the mutually same or equal part in the figure, and the description is used about the part of the same code | symbol.

  First, the overall schematic configuration of the engine control system will be described with reference to FIG. In the cylinder injection engine (hereinafter referred to as the engine 10) shown in FIG. 1, an airflow meter 12 for detecting the amount of intake air is provided at 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 downstream of the air flow meter 12, and the opening degree (throttle opening degree) of the throttle valve 14 is incorporated in the throttle actuator 13. It is detected by the throttle opening sensor detected. A surge tank 16 is provided downstream of the throttle valve 14, and the surge tank 16 is provided with an intake pipe pressure sensor 17 for detecting an intake pipe pressure. An intake manifold 18 for introducing air to 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, which is the upstream side of the injector 21 described later), a partition plate 50 is provided for each cylinder to partition the intake passage up and down. And the lower side passage 52 are formed. A tumble control valve (TCV) 53 for opening and closing the lower passage 52 is disposed at an inlet portion of the lower passage 52 of each cylinder. The TCV 53 is an air flow control valve that adjusts the strength of the air flow (the strength of the 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 TCV 53, it is possible to generate an intake swirling flow (tumble flow) in the longitudinal direction in the cylinder, and to adjust its swirling position.

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

  The high pressure fuel system will be briefly described. This system comprises a low pressure pump 25 for pumping fuel in the fuel tank 24, a high pressure pump 26 for pressurizing the low pressure fuel pumped up by the low pressure pump 25, and an accumulator chamber for storing high pressure fuel discharged from the high pressure pump 26. And a delivery pipe 27 that constitutes the The injectors 21 of the respective cylinders are connected to the delivery pipe 27 respectively. The high pressure fuel which is pressurized by the high pressure pump 26 and stored in the delivery pipe 27 is injected by the injector 21 into the combustion chamber 23 (within the cylinder). Further, a fuel pressure sensor 29 for detecting a fuel pressure (fuel pressure) is provided in the high pressure fuel pipe 28 connecting the high pressure pump 26 and the delivery pipe 27 or the delivery pipe 27.

  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 a 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 maximum. The fuel pressure control valve 26a comprises a suction control valve for adjusting the amount of fuel drawn into the fuel pressurizing chamber of the high pressure pump 26, or a discharge control valve for adjusting 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, at an intake port and an exhaust port of the engine 10, an intake valve 31 and an exhaust valve 32 which are opened and closed in accordance with the rotation of a cam shaft (not shown) are provided. 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 make the opening and closing timings of the respective valves variable. The variable valve mechanisms 31A and 32A adjust the relative rotational phase between the crankshaft of the engine 10 and the intake camshaft, and can adjust the phase to the advance side and the retard side with respect to a predetermined reference position. It has become. As the variable valve mechanism 31A, 32A, a hydraulic drive type or an electric type variable valve mechanism is used.

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

  The exhaust pipe 33 is provided with a purification device 35 for purifying the exhaust gas. The purification device 35 is, for example, a selective reduction catalytic converter (SCR catalytic converter), an NOx storage reduction type catalyst, a three-way catalyst, or the like. 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 exhaust gas as the detection target is provided.

  In addition, a rectangular crank angle signal is output to the cylinder block 20 at each predetermined crank angle of the engine 10 (for example, at a cycle of 10 ° CA) to the water temperature sensor 37 for detecting engine water temperature (corresponding to engine temperature) The 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 an ECU 40) as a control device that controls engine control. The ECU 40 is configured to have a microcomputer including a CPU, a ROM, a RAM, etc., and controls the fuel injection amount of the injector 21 according to the engine operating condition by executing various control programs stored in the ROM. Control the ignition timing of the spark plug 34, etc., or carry out the fuel pressure control.

  For example, the ECU 40 controls the driving of the high pressure pump 26 to perform fuel pressure control to maintain the fuel pressure in the delivery pipe 27, ie, 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, basic control of fuel injection will be described. The ECU 40 uses the engine load (for example, the intake air amount) and the engine rotational speed as parameters, and calculates a basic injection amount based on these parameters. Then, the ECU 40 appropriately performs water temperature correction, air-fuel ratio correction, and the like on the basic injection amount to calculate 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 based on the injection signal.

  In the present embodiment, fuel is injected in each of the intake stroke and the compression stroke. That is, the ECU 40 injects fuel in the intake stroke (by intake stroke injection) to form a homogeneous mixture in the combustion chamber 23. Then, the ECU 40 injects fuel in the compression stroke (by 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 in the vicinity of the spark plug 34 is present at the ignition timing. However, when performing split injection, the injection amount injected in the compression stroke tends to be smaller than when not performing split injection, and the penetration of the fuel jet tends to be weak.

  Therefore, in the compression stroke, the strength of the fluid flow in the combustion chamber 23 may not correspond to the penetration of the fuel jet. In this case, as shown in FIG. 2, in the compression stroke, there is a high possibility that the fuel jet can overtake the momentum of the fluid flow and the fuel (air flow) can not be well loaded (mixed). That is, the fuel is dispersed near the wall surface of the combustion chamber 23, and there is a high possibility that the air-fuel mixture having a desired air-fuel ratio can not be suitably present near the spark plug 34 at the ignition timing. Therefore, in order to allow the air-fuel mixture in the vicinity of the spark plug 34 to have a desired air-fuel ratio suitably 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 infer fuel and inject fuel with penetration according to the strength of compression flow.

  Therefore, the ECU 40 executes the control process related to the following injection control in order to preferably cause the air-fuel mixture that has become a desired air-fuel ratio in the vicinity of the spark plug 34 at the ignition timing. The control process is executed by the ECU 40 for each combustion cycle.

  As shown in FIG. 3, the ECU 40 calculates a base value which is a basis for calculating the strength of the compression flow and a swirling position of the eddy current 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 assuming that the airflow control by the TCV 53 is not performed, and is a value calculated by the engine operating state. The base value is also a basic value for determining how to perform control when performing airflow control described later.

  Specifically, the swirling position of the vortex generated in the combustion chamber 23 is 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 condition, assuming that the airflow control by the TCV 53 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 corresponding to the engine rotational speed and the engine load, and the center position K of the tumble flow corresponding to the engine rotational speed and the engine load are acquired in advance by a matching test, and are mapped and stored. 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 has a function as a position estimation unit that estimates the swirling position (the center position K of the tumble flow) in the combustion chamber 23.

  Next, the ECU 40 calculates a target fuel pressure to be a basis for calculating the final fuel pressure, and calculates a basic injection amount in each stroke (step S102). In step S102, the ECU 40 calculates a target fuel pressure to be a basis for calculating the final fuel pressure, based on the engine operating condition (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. In addition, the range of the injection amount which can be injected in each process is defined, and the basic injection quantity in each process is comprised so that it may be divided | segmented within each range. In addition, the range of the injection quantity which can be injected in each process is set by the conformity test etc. based on an emission requirement, a viewpoint of ignition stability, etc.

  Next, the ECU 40 determines whether the base value calculated in step S101 is equal to or greater than a predetermined threshold Th (step S103). If the base value is equal to or greater than the predetermined threshold Th (step S103: YES), the ECU 40 performs the 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 flow is controlled by adjusting the opening degree of the TCV 53 so that the central position K of the tumble flow is adjusted to be lower than the fuel injection position (direction). The control amount of the TCV 53 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), the combustion chamber 23 is made to go around and reach 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 tumble flow speed in the combustion chamber 23 is high, the distance the fuel (air-fuel mixture) travels on the tumble flow with the center position K below the fuel injection position is Lengthen. Thus, 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 Th (step S103: NO), the ECU 40 controls the intake flow so that the estimated center position K of the tumble flow is above the fuel injection position. It controls (step S105). The control amount of the TCV 53 is determined 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), as shown in FIG. It reaches near the spark plug 34 before going around the inside of the chamber 23. Therefore, when the fluid flow is weak and the tumble flow speed in the combustion chamber 23 is low, the distance the fuel (air-fuel mixture) travels on the tumble flow is shortened with the central position K above the fuel injection position. Do. Thus, 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 the TCV 53 is performed in steps S104 and S105, the strength of the compression flow is also affected. That is, since the strength of the compression flow is considered to depend on the intake flow after the air flow control, it is necessary to correct the base value (the strength estimated in step S101).

  Therefore, the ECU 40 corrects the base value to estimate the strength of the compression flow (step S106). That is, in step S106, the strength of the compression flow is estimated when the airflow control (control of the intake flow) based on steps S104 and S105 is performed.

  Specifically, based on the control amount of the TCV 53, the correction amount of the base value is obtained in advance by a conformance test, mapped and stored. Then, the ECU 40 refers to the map, corrects the base value based on the control amount of the TCV 53 determined in steps S104 and S105, and estimates the strength of the compression flow.

  By executing the processing of steps S101 and S106, the ECU 40 estimates the strength of the compression flow based on the engine operating state (engine rotational speed and engine load) and the control state of the TCV 53. That is, the ECU 40 estimates the strength of the compression flow by calculating the base value based on the engine operating state and correcting the calculated base value based on the control state of the TCV 53. By executing the processing of steps S101 and S106, the ECU 40 has a function as a flow estimation unit 41 that estimates the strength of the fluid flow in the combustion chamber 23 in the compression stroke.

  Next, the ECU 40 calculates the penetration of the fuel jet required in the compression stroke (request penetration) 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 of the fuel jet in the compression stroke satisfies the required penetration, and determines the injection amount in the compression stroke injection, and then in the compression stroke. The penetration 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 to the case where the compression flow is small. When the injection amount in the compression stroke is increased, it is necessary to decrease the injection amount in the intake stroke accordingly.

  Further, as described above, since the injection amount that can be injected in each stroke is determined in advance, the injection amount in the compression stroke is determined (changed so that the injection amount in each stroke falls within each range). ). For this reason, when the injection amount can not be determined so that the penetration of the fuel jet in the compression stroke satisfies the required penetration within the range of the injection amount in the compression stroke (when it is less than the required penetration) In the compression stroke, the upper limit value in the injection possible range is determined as the injection amount.

  Next, the ECU 40 adjusts the penetration by changing the fuel pressure (injection pressure) so that the penetration of the fuel jet in the compression stroke satisfies the required penetration (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 to the case where the compression flow is small. In step S109, assuming that the fuel is injected with the injection amount set in step S108, 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. .

  Specifically, when the fuel is injected with the injection amount set in step S108, the ECU 40 is the basis calculated in step S102 so that the penetration of the fuel jet in the compression stroke satisfies the required penetration. Correct (change) the target fuel pressure. Then, 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 ends.

  By executing the processes of steps S108 and S109, the ECU 40 has a function as the adjustment unit 42 that adjusts the penetration 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 has a function as a first adjustment unit that adjusts 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 that adjusts the penetration force by changing the injection pressure that is the pressure of the fuel injected from the injector 21. Become.

  Since step S108 is performed before step S109, when adjusting the penetration based on the strength of the fluid flow, the first adjusting unit of the first adjusting unit and the second adjusting unit is used. It can be said that the adjustment is implemented preferentially.

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

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

  When intake stroke injection and compression stroke injection are respectively performed in one combustion cycle, homogeneous mixture is formed in the cylinder by the intake stroke injection, while suitable fuel ignition is realized by the compression stroke injection. . However, at the time of performing such split injection, the amount of injection in compression stroke injection decreases, so that the fuel jet is pushed in a state where the inside of the combustion chamber 23 becomes highly fluid, and fuel is loaded on the fluid (air flow) well. There is a high possibility that it can not be (mixed). That is, the fuel is dispersed near the wall surface of the combustion chamber 23, and there is a high possibility that the mixture having the desired air-fuel ratio can not be present near the spark plug 34 at the ignition timing.

  In this respect, in the above configuration, the strength of the fluid flow in the combustion chamber 23 in the compression stroke is estimated, and the penetration of the fuel jet in the compression stroke is based on the estimated strength of the fluid flow (compression flow). Adjusted. Therefore, the penetration force of the fuel jet can be adjusted to correspond to the strength of the compression flow, and 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. .

  It is conceivable that the penetration of the fuel jet will be increased by increasing the fuel injection amount. By utilizing this, when the strength of fluid flow in the combustion chamber 23 is large, the injection amount in the compression stroke is increased as compared with the case where it is small. As a result, even when the strength of fluid flow (compression flow) in the combustion chamber 23 is large, it is preferable to preferably cause an air-fuel mixture having a desired air-fuel ratio in the vicinity of the spark plug 34 at the ignition timing. it can.

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

  In the above configuration, the penetration force is adjusted by changing the injection amount and the injection pressure. For this reason, even if the range which can be set in any one or both is limited, the degree of freedom of adjustment can be improved.

  In addition, when the injection pressure (fuel pressure) is increased, the output of the engine 10 is used, so the fuel efficiency is deteriorated. Therefore, when adjusting the penetration power according to the required penetration power, the influence on the fuel efficiency is reduced by changing the injection amount preferentially. Further, in the above-described embodiment, the ECU 40 changes the injection pressure (fuel pressure) in step S109 when the injection amount reaches the predetermined upper limit. For this reason, the change in fuel pressure can be minimized, and the impact on fuel consumption can be minimized.

  In order to adjust the center position K of the tumble flow so that the mixture suitably exists near the spark plug 34 at the ignition timing, the airflow control (control of the intake flow) by the TCV 53 as an airflow control valve is performed. Specifically, when the base value is strong, the opening adjustment of the TCV 53 is performed 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 adjustment of the TCV 53 is performed 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 fluid flow in the compression stroke only from the engine operating state. Therefore, the ECU 40 estimates the strength of the fluid flow in the compression stroke based on the engine operating state and the control state of the TCV 53. 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 TCV 53, and estimates the strength of the compression flow. Thereby, even if the intake flow is controlled by the TCV 53, 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, for example, as follows.

  In the above embodiment, the central position K of the tumble flow is adjusted by adjusting the opening of the TCV 53, but the profile (opening timing, lift amount, etc.) of the intake valve 31 is adjusted to adjust the central position K of the tumble flow. You may In this case, the intake valve 31 corresponds to an air flow control valve.

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

  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, in the case where the strength of the compression flow is equal to or higher than the threshold and the center position of the tumble flow is below the fuel injection position, adjustment is made to increase the penetration of the fuel jet in the compression stroke. Good. On the other hand, when the strength of the compression flow is smaller than the threshold or when 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. . Thus, it is possible to more suitably cause the air-fuel mixture having a desired air-fuel ratio in the vicinity of the spark plug 34 at the ignition timing.

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

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

  In the above embodiment, the central position K of the tumble flow may not be adjusted.

  DESCRIPTION OF SYMBOLS 10 ... Engine, 21 ... Injector, 23 ... Combustion chamber, 40 ... ECU, 41 ... Flow estimation part, 42 ... Adjustment part.

Claims (7)

The present invention is applied to an internal combustion engine (10) provided with a fuel injection valve (21) for directly injecting fuel into a combustion chamber (23), and fuel injection in one combustion cycle of the internal combustion engine can be In a control device (40) of an internal combustion engine to be divided and executed,
A flow estimation unit (41) for estimating the strength of fluid flow in the combustion chamber in the compression stroke;
An adjustment unit (42) for adjusting the penetration of the fuel jet in the compression stroke based on the strength of the fluid flow inferred by the flow estimation unit;
A control device for an internal combustion engine comprising:   The internal combustion engine according to claim 1, wherein the adjusting unit adjusts the penetration force by increasing the injection amount in the compression stroke injection when the fluid flow intensity is high compared to when the fluid flow intensity is low. Control device.   When the strength of the fluid flow is large, the adjusting unit adjusts the penetration force by increasing the injection pressure which is the pressure of the fuel injected from the fuel injection valve as compared to the case where the strength is small. The control device for an internal combustion engine according to 1 or 2. The adjustment unit is
A first adjustment unit (40) for adjusting the penetration force by changing the injection amount in the compression stroke injection;
A second adjustment unit (40) for adjusting the penetration force by changing an injection pressure which is a pressure of fuel injected from the fuel injection valve;
When adjusting the penetration force based on the strength of the fluid flow, the adjustment by the first adjustment unit of the first adjustment unit and the second adjustment unit is preferentially performed. Control system for internal combustion engines.   In the case where the adjustment unit is performing adjustment by the first adjustment unit among the first adjustment unit and the second adjustment unit, the adjustment amount is based on the fact that the adjustment amount becomes a predetermined upper limit. The control device for an internal combustion engine according to claim 4, wherein the adjustment by the second adjustment unit is performed. In the internal combustion engine, an air flow control valve (53) is provided in the intake passage,
The control device for an internal combustion engine according to any one of claims 1 to 5, wherein the flow estimation unit estimates the strength of the fluid flow based on an engine operating state and a control state of the air flow control valve. . And a position estimation unit (40) for estimating the swirling position of the eddy current in the combustion chamber when performing the airflow control by the airflow control valve;
The control device for an internal combustion engine according to claim 6, wherein the adjustment unit adjusts the penetration force based on the strength of the fluid flow and the swirl position of the vortex flow.

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