JP6090641B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine control device, and more particularly to an internal combustion engine control device applied to an internal combustion engine having a supercharger, an in-cylinder injection valve, and a variable valve mechanism.

  Spark ignition type internal combustion engines include direct injection gasoline engines having a supercharger and an in-cylinder injection valve that injects fuel directly into the cylinder. In a direct injection gasoline engine with a supercharger, it is known to inject fuel in both an intake stroke and a compression stroke.

  For example, a control device for an engine with a turbocharger disclosed in Patent Document 1 determines whether or not the vehicle is in an accelerating state according to detection signals of an accelerator opening sensor and an airflow sensor. And this control apparatus divides | segments into an intake stroke and the latter half of a compression stroke in the acceleration first period, and injects a fuel into a cylinder injection valve. According to this control device, the exhaust gas energy required for driving the turbine of the turbocharger is sufficiently ensured, and the turbocharger can be quickly charged to accelerate the vehicle. It is supposed to improve.

  On the other hand, an engine with a supercharger includes a direct injection gasoline engine having a port injection valve that injects fuel into an intake port and a variable valve mechanism that adjusts opening and closing timings (operation angles) of the intake valve and the exhaust valve. is there. In this type of direct-injection gasoline engine, it is known that an overlap period in which the opening timing of the intake valve and the opening timing of the exhaust valve overlap is adjusted by a variable valve mechanism.

  For example, the control device for an internal combustion engine disclosed in Patent Document 1 determines that the lean combustion is being performed and satisfies the first condition that it is determined that there is an acceleration request. The variable valve mechanism is controlled so as to increase the amount of overlap during the valve opening period.

  According to Patent Document 1, since the overlap amount is increased when the first condition is satisfied, the amount of air-fuel mixture flowing into the cylinder is increased, the exhaust energy is also increased, and the supercharging pressure is increased. The torque is supposed to increase. According to Patent Document 1, the lean combustion region is expanded, and even in an internal combustion engine equipped with a supercharger, it is possible to meet the acceleration demand while maintaining lean combustion, and improvement in practical fuel consumption is expected as a benefit of lean combustion. It is said that.

JP 2000-54894 A (paragraph numbers 0053, 0054, etc.) JP 2008-25545 A (Claim 1, paragraph number 0011, etc.)

For a direct injection gasoline engine with a supercharger, further improvement in acceleration performance is desired, and in particular, improvement in acceleration performance during rapid acceleration is desired.
As disclosed in Patent Document 2, even if the overlap amount is increased in the lean combustion region, there is a limit to improving the acceleration performance during sudden acceleration.
The present invention has been made in view of the above circumstances, and an object thereof is to improve the acceleration performance at the time of rapid acceleration of an internal combustion engine having a supercharger, an in-cylinder injection valve, and a variable valve mechanism. It is to provide a control device.

In order to achieve the above object, according to one aspect of the present invention, a supercharger, in-cylinder fuel injection means for directly injecting fuel into a combustion chamber, exhaust valve closing timing and intake valve opening timing are provided. When accelerating an internal combustion engine having a valve timing varying means for adjusting at least one of them, the valve timing varying means increases the valve overlap period in which the exhaust valve closing timing and the intake valve opening timing overlap. In the control apparatus for an internal combustion engine, a determination unit that compares the detected value of the change rate of the accelerator opening with the first threshold value and a second threshold value that is larger than the first threshold value, and a detection value as a result of comparison by the determination unit In the first case where the value is equal to or more than the first threshold value and less than the second threshold value, the valve timing variable means changes at least one of the exhaust valve closing timing and the intake valve opening timing at the first rate of change. In the second case where the value is greater than or equal to the second threshold value, at least one of the exhaust valve closing timing and the intake valve opening timing is set to a second change rate larger than the first change rate by the valve timing variable means. Valve timing control means for changing and increasing the valve overlap period,
In the second case, the valve timing control means sets the target value to the second change rate so that at least one target value of the exhaust valve closing timing and the intake valve opening timing becomes an acceleration optimum value. If the most recent detected value of the accelerator opening is less than the acceleration request end determination threshold value or the elapsed time from the acceleration request to the internal combustion engine exceeds the acceleration time determination threshold value, the valve over The valve timing control for increasing the lap period is terminated and the routine is shifted to normal valve timing control .
The control device includes split injection control means for performing split injection in which fuel is injected into the combustion chamber by the in-cylinder fuel injection means in both the intake stroke and the compression stroke, and the change rate of the accelerator opening is changed. When the detected value is less than a first threshold value, fuel is injected into the in-cylinder fuel injection means during the intake stroke, and the divided injection control means is caused to execute the divided injection in the first and second cases. A control apparatus for an internal combustion engine is provided.

In the control apparatus for an internal combustion engine according to one aspect, the exhaust valve is closed at a second change rate larger than the first change rate when the change rate of the accelerator opening is determined to be equal to or greater than the second threshold value. At least one of the timing and the intake valve opening timing is changed. In other words, the valve overlap period is more rapid at the time of rapid acceleration when the change rate of the accelerator opening is equal to or greater than the second threshold than at the time of normal acceleration where the change rate of the accelerator opening is greater than or equal to the first threshold and less than the second threshold. Will be increased. Further, due to the rapid increase in the valve overlap period, good scavenging efficiency is maintained even during rapid acceleration, and torque is improved.
In the second case, the valve timing control means sets the target value at the second rate of change so that at least one of the exhaust valve closing timing and the intake valve opening timing becomes the acceleration optimum value. The valve overlap period is increased when the detected value of the most recent accelerator opening is less than the acceleration request end determination threshold or when the elapsed time from the acceleration request to the internal combustion engine exceeds the acceleration time determination threshold. The valve timing control to be performed is terminated and the routine proceeds to normal valve timing control .

In the second case, the control device for an internal combustion engine further includes split injection control means for performing split injection in which fuel is injected into the combustion chamber by the in-cylinder fuel injection means in both the intake stroke and the compression stroke. Has been .
In this case, the torque is further improved by executing the divided injection when it is determined that the detected value is equal to or greater than the second threshold value.

  The internal combustion engine further includes port fuel injection means for performing port injection for injecting fuel into the intake port, the split injection control means executes split injection in the first case, and the control device is in the second case. The port injection may be prohibited in the state where the divided injection is performed, and in the first case, it may be configured to further include a port injection control unit that executes the port injection in parallel with the divided injection. .

According to this configuration, in the first case, since port injection is used in parallel with in-cylinder injection, unburned components and the like contained in the exhaust gas are reduced. For this reason, environmentally friendly control is possible while ensuring acceleration performance according to the driver's request.
On the other hand, in the second case, execution of port injection is prohibited and only in-cylinder injection is executed, so that even better acceleration performance can be obtained.

In the second case, the valve timing control means may be configured to stepwise change at least one target value of the exhaust valve closing timing and the intake valve opening timing to the acceleration optimum value.
In this case, the valve overlap period can be reliably and rapidly increased by stepwise changing the target value of at least one of the exhaust valve closing timing and the intake valve opening timing to the acceleration optimum value.

The control apparatus for an internal combustion engine includes first valve phase map data for setting a target value of at least one of an exhaust valve closing timing and an intake valve opening timing in the first case, and an exhaust valve in the second case. Storage means for storing second valve phase map data different from the first valve phase map data for setting a target value of at least one of the valve closing timing and the intake valve opening timing is further provided. Also good.
According to this configuration, the valve overlap period can be reliably and rapidly increased by using the second valve phase map data.

The storage means includes first ignition timing map data for setting a target value for ignition timing in the first case, and first ignition timing map data for setting a target value for ignition timing in the second case. Is for setting another target ignition timing map data in the second case, second ignition timing map data for setting the target value for the fuel injection timing in the first case, and for the second case. The second injection timing map data different from the first injection timing map data may be further stored.
According to this configuration, in the second case, the ignition timing and the fuel injection timing are adjusted based on the second ignition timing map data and the second injection timing map data, respectively, thereby further improving the torque during rapid acceleration. Can be made.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus of an internal combustion engine which improves the acceleration performance at the time of rapid acceleration of the internal combustion engine which has a supercharger, a cylinder injection valve, and a variable valve mechanism is provided.

It is a figure for demonstrating the structure of the control apparatus of the internal combustion engine which concerns on a 1st basic form. It is a flowchart which shows the schematic procedure of the VVT control method which the control apparatus of FIG. 1 performs. FIG. 3 is a schematic timing chart when the VVT control method of FIG. 2 is executed, where (a) is an accelerator opening change amount, (b) is a target phase of intake VVT, (c) is a target phase of exhaust VVT, and (D) shows the change with time of torque. It is a figure for demonstrating the structure of the control apparatus of the internal combustion engine which concerns on a 2nd basic form. 5 is a flowchart showing a schematic procedure of a VVT control method executed by the control device of FIG. 4. 6 is a schematic timing chart when the VVT control method of FIG. 5 is executed, where (a) is an accelerator opening change amount, (b) is a target phase of intake VVT, (c) is a target phase of exhaust VVT, ( (d) is the torque, (e) is the actual phase of the intake VVT, (f) is the actual phase of the exhaust VVT, (g) is the fuel injection timing, and (h) is the time variation of the ignition timing. . It is a figure for demonstrating the structure of the control apparatus of the internal combustion engine which concerns on 1st Embodiment. It is a flowchart which shows the schematic procedure of the VVT and division | segmentation injection control method which the control apparatus of FIG. 7 performs. FIG. 9 is a schematic timing chart when the VVT / split injection control method of FIG. 8 is executed, in which (a) is an accelerator opening change amount, (b) is a target phase of intake VVT, and (c) is a target of exhaust VVT. Phase, (d) shows torque, (i) shows on / off of divided injection, and (j) shows time change with respect to port injection ratio. It is a figure for demonstrating the structure of the control apparatus of the internal combustion engine which concerns on 2nd Embodiment. It is a flowchart which shows the schematic procedure of the VVT and division | segmentation injection control method which the control apparatus of FIG. 10 performs.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

(First basic form)
FIG. 1 shows a schematic configuration of an internal combustion engine 10 and a control device 12 of the internal combustion engine 10 according to the first basic form. The internal combustion engine 10 and the control device 12 are mounted on a vehicle (not shown).

  The internal combustion engine 10 includes a crankcase 14 and a cylinder block 16, and one or more cylinders 18 are defined inside the cylinder block 16. A crankshaft 20 is rotatably disposed in the crankcase 14, and a piston 22 is reciprocally disposed in each cylinder 18. The piston 22 is connected to the crankshaft 20 via a connecting rod 24.

  A cylinder head 26 is attached to the cylinder block 16. The cylinder head is disposed so as to close the open end of the cylinder 18, and a combustion chamber 28 is formed between the piston 22 and the cylinder head 26.

The cylinder head 26, intake ports 30 and exhaust ports 32 communicating with provided combustion chamber 28, an intake port 30 and exhaust port 32, intake valve 34 and exhaust valve 35 are respectively provided. The intake valve 34 is reciprocated by an intake cam 36 to open and close the intake port 30. The exhaust valve 35 is reciprocated by an exhaust cam 37 to open and close the exhaust port 32.

  The intake cam 36 is provided with an intake VVT (variable valve timing) mechanism 38, and the control device 12 controls the intake VVT mechanism 38, which is a valve timing variable means of the intake valve 34, thereby opening and closing timing of the intake valve 34. Can be adjusted. The intake VVT mechanism 38 uses, for example, hydraulic pressure or electromagnetic force to change the phase of the camshaft that rotates the intake cam 36 with respect to the phase of the crankshaft 20, thereby opening and closing the intake valve 34 (working angle). Can be adjusted.

  On the other hand, the exhaust cam 37 is provided with an exhaust VVT (variable valve timing) mechanism 39, and the control device 12 controls the exhaust VVT mechanism 39, which is a valve timing varying means of the exhaust valve 35, to thereby control the exhaust valve 35. The opening and closing time can be adjusted. The exhaust VVT mechanism 39 uses, for example, hydraulic pressure or electromagnetic force to change the phase of the camshaft that rotates the exhaust cam 37 with respect to the phase of the crankshaft 20, thereby opening and closing the exhaust valve 35 (working angle). Can be adjusted.

Further, in-cylinder injection valves (in-cylinder fuel injection valves) 42 are attached to the cylinder head 26 corresponding to the respective cylinders 18. The in-cylinder injection valve 42 constitutes an in-cylinder fuel injection unit that directly injects fuel into the combustion chamber 28. The fuel is gasoline, and fuel is supplied to the in-cylinder injection valve 42 from a fuel tank through a feed pump and a high-pressure pump, although not shown. The in-cylinder injection valve 42 opens and closes according to a command from the control device 12 and injects fuel into the combustion chamber 28 with a predetermined injection amount.
Further, a spark plug 44 is attached to the cylinder head 26 corresponding to each cylinder 18, and the spark plug 44 ignites and burns an air-fuel mixture containing fuel in the combustion chamber 28.

An intake passage 46 is connected to the intake port 30. The intake passage 46 is a passage for supplying air to the combustion chamber 28 and is constituted by piping or the like. The intake passage 46 includes an air filter 48 for purifying air, a compressor 50 for compressing air, an intercooler 52 for cooling the compressed air, and a throttle valve for adjusting the flow rate of air. 54 is provided.
The throttle valve 54 is, for example, an electronic control valve (ETV) that can electronically control the opening degree, and the throttle valve 54 is driven by a throttle valve actuator 55.

  An exhaust passage 56 is connected to the exhaust port 32. The exhaust passage 56 is a passage for exhausting exhaust gas from the combustion chamber 28, and is configured by piping or the like. The exhaust passage 56 is provided with an exhaust turbine 58 driven by exhaust, a catalyst 60 for purifying exhaust, and a muffler 62 for silencing.

  The exhaust turbine 58 is connected to the compressor 50, and the power of the exhaust turbine 58 driven by the exhaust is used as power for the compressor 50 to compress air. That is, the compressor 50 and the exhaust turbine 58 constitute a supercharger 64 composed of an exhaust turbocharger, and the internal combustion engine 10 is a direct injection gasoline engine having the supercharger 64.

The internal combustion engine 10 has a plurality of types of sensors.
Specifically, the internal combustion engine 10 includes an air flow sensor 66, a throttle valve opening sensor, an air-fuel ratio sensor 67, a crank rotation angle sensor 68, and an accelerator opening sensor 69.
The air flow sensor 66 is provided in a portion of the intake passage 46 downstream of the air filter 48 and detects the flow rate of the intake air.

The throttle valve opening sensor is a sensor for measuring the opening of the throttle valve 54. In the present embodiment, the throttle valve actuator 55 also serves as the throttle valve opening sensor. Therefore, hereinafter, it is also referred to as a throttle valve opening sensor 55.
Air-fuel ratio sensor 67 is provided in the exhaust passage path 56, it detects the oxygen concentration. The oxygen concentration is used to obtain an air / fuel ratio (A / F) by calculation.

The crank rotation angle sensor 68 is provided in the vicinity of the crankshaft 20 and detects the rotation angle of the crankshaft 20.
The accelerator opening sensor 69 is provided in the vicinity of the accelerator pedal, and can detect the accelerator opening and the amount of change per unit time of the accelerator opening, that is, the changing speed of the accelerator opening.

  Intake flow, throttle valve opening, oxygen detected continuously or intermittently by the air flow sensor 66, throttle valve opening sensor 55, air-fuel ratio sensor 67, crank rotation angle sensor 68, and accelerator opening sensor 69 The detected values of the concentration, the rotation angle of the crankshaft, the accelerator opening, and the change speed of the accelerator opening are input to the control device 12 continuously or intermittently.

The control device 12 is configured by, for example, an ECU (electronic central control device), and is configured by a CPU (central processing unit), a memory, an external storage device, an input / output device, and the like.
The control device 12 is a control unit that controls the entire vehicle including the internal combustion engine 10.

  The control device 12 determines the amount of fuel supplied into the combustion chamber 28 by the in-cylinder injection valve 42 according to the input accelerator opening, the detected value of the change rate of the accelerator opening, and the oxygen concentration, and The amount of intake air supplied into the combustion chamber 28 through the throttle valve 54 is adjusted. The control device 12 also controls the fuel supply timing (injection timing) and the ignition timing of the spark plug 44 based on the input detected value of the rotation angle of the crankshaft 20.

  Here, FIG. 1 schematically shows a functional configuration of the control device 12 of the present embodiment. The control device 12 includes an acceleration request determination unit (determination unit) 70, an acceleration level determination unit (determination unit) 72, a valve timing control unit (valve timing control unit) 74, an acceleration request end determination unit 76, and an acceleration time determination unit. 78.

  The acceleration request determination unit 70 compares the input detection value ΔAPS of the latest accelerator opening change speed with a predetermined acceleration request determination threshold (first threshold) ΔAPSth1. Then, when the detected value ΔAPS becomes equal to or greater than the acceleration request determination threshold value ΔAPSth1, the acceleration request determination unit 70 determines that the driver requests acceleration, and the detected value ΔAPS is less than the predetermined acceleration request determination threshold value ΔAPSth1. If there is, it is determined that the driver does not request acceleration.

The acceleration level determination unit 72 sets the input acceleration speed change ΔAPS of the latest accelerator opening at the same time as or immediately after the acceleration request determination unit 70 performs the determination. Threshold) ΔAPSth2 is compared. The acceleration level determination threshold value ΔAPSth2 is larger than the acceleration request determination threshold value ΔAPSth1.
The control device 12 includes the acceleration request determination unit 70 and the acceleration level determination unit 72, but includes a determination unit that compares the detection value ΔAPS with the acceleration request determination threshold value ΔAPSth1 and the acceleration level determination threshold value ΔAPSth2. It only has to be.

The valve timing control unit 74 controls the intake VVT mechanism 38 and the exhaust VVT mechanism 39 as usual, when the latest change rate ΔAPS of the accelerator opening is less than the acceleration level determination threshold ΔAPSth2.
On the other hand, when the input change rate ΔAPS of the latest accelerator opening is equal to or greater than the acceleration level determination threshold ΔAPSth2, the valve timing control unit 74 sets the valve opening timing of the intake valve 34 to the most advanced angle for a predetermined period. The intake VVT mechanism 38 is controlled so that the exhaust valve 35 is closed, and the exhaust VVT mechanism 39 is controlled so that the valve closing timing of the exhaust valve 35 is most retarded.

  Specifically, when the input change rate ΔAPS of the latest accelerator opening is equal to or higher than the acceleration level determination threshold ΔAPSth2, the valve timing control unit 74 sets the VVT target phase of the intake valve 34 to the most advanced angle ( The target phase of the VVT of the exhaust valve 35 is changed stepwise so that it becomes the most retarded angle (acceleration optimum value).

  When the detected value ΔAPS is equal to or greater than the acceleration request determination threshold ΔAPSth1 and less than the acceleration level determination threshold ΔAPSth2, when the intake VVT mechanism 38 is controlled as usual, the intake valve 34 is set at a predetermined rate of change. The valve opening timing of the exhaust valve 35 is advanced, and the valve closing timing of the exhaust valve 35 is retarded at a predetermined rate of change.

  The acceleration request end determination unit 76 compares the input detection value APS of the latest accelerator opening with a predetermined acceleration request end determination threshold APSth. The acceleration request end determination unit 76 determines that the driver's request for acceleration has ended when the detection value APS is less than the acceleration request end determination threshold APSth.

  The acceleration time determination unit 78 compares the acceleration time Tac with a predetermined acceleration time determination threshold value Tacth. The acceleration time Tac is an elapsed time from when the acceleration request determination unit 70 determines that there is a request for acceleration. The acceleration time determination unit 78 determines that the acceleration time has ended when the acceleration time Tac exceeds the acceleration time determination threshold value Tacth.

  The valve timing control unit 74 controls to maintain the valve opening timing of the intake valve 34 at the most advanced angle when it is determined that the driver's request for acceleration has been completed or the acceleration time has been completed. And the control for maintaining the closing timing of the exhaust valve 35 at the most retarded angle is released, and the control of the intake VVT mechanism 38 and the exhaust VVT mechanism 39 as usual is executed.

  Next, a VVT (variable valve timing) control method executed by the control device 12 of the internal combustion engine 10 will be described with reference to FIG. FIG. 2 is a flowchart showing a schematic procedure of the VVT control method. The control method of FIG. 2 is repeatedly executed during operation of the internal combustion engine 10.

  In the VVT control method, an acceleration request determination step S10 is first performed. In the acceleration request determination step S10, the input detection value ΔAPS of the latest accelerator opening change speed is compared with a preset acceleration request determination threshold value ΔAPSth1.

  If the detection value ΔAPS is equal to or greater than the acceleration request determination threshold value ΔAPSth1 as a result of the comparison in the acceleration request determination step S10, the acceleration level determination step S12 is executed. In the acceleration level determination step S12, the input detection value ΔAPS of the latest accelerator opening change speed is compared with a preset acceleration level determination threshold value ΔAPSth2.

  As a result of the comparison in the acceleration level determination step S12, if the detected value ΔAPS is equal to or greater than the acceleration level determination threshold ΔAPSth2, the target phase of the VVT (intake VVT) of the intake valve 34 is set to the most advanced angle (S14). The target phase of VVT (exhaust VVT) of the exhaust valve 35 is set to the most retarded angle (S16).

  In FIG. 2, the acceleration request determination step S10 and the acceleration level determination step S12 are distinguished from each other, but the acceleration request determination step S10 and the acceleration level determination step S12 may be performed simultaneously. That is, there may be a determination step for comparing the detected value ΔAPS with the acceleration request determination threshold value ΔAPSth1 and the acceleration level determination threshold value ΔAPSth2.

In step S14, the target phase of the intake VVT is set to the most advanced angle, and in step S16, the target phase of the exhaust VVT is set to the most retarded angle, and then the acceleration request end determining step S18 is executed.
In the acceleration request end determination step S18, it is determined whether or not the input detection value APS of the latest accelerator opening is equal to or greater than the acceleration request end determination threshold APSth. As a result of the determination, if the detected value APS is greater than or equal to the acceleration request end determination threshold APSth, the acceleration time determination step S20 is executed.

  In the acceleration time determination step S20, it is determined whether or not the acceleration time Tac is equal to or less than the acceleration time determination threshold value Tacth. As a result of the determination, if the acceleration time Tac is equal to or less than the acceleration time determination threshold value Tacth, the acceleration request end determination step S18 is executed again.

  On the other hand, if the acceleration time Tac exceeds the acceleration time determination threshold value Tacth as a result of the determination in the acceleration time determination step S20, normal VVT control is executed (S22). That is, the state in which the intake VVT is maintained at the most advanced angle and the state in which the exhaust VVT is maintained at the most retarded angle are released, and normal VVT control is executed.

  When the detection result ΔAPS is less than the acceleration request determination threshold ΔAPSth1, the determination result of the acceleration request determination step S10, when the detection value ΔAPS is less than the acceleration level determination threshold ΔAPSth2, As a result of the determination in the acceleration request end determination step S18, the normal VVT control in step S22 is also executed when the detected value APS is less than the acceleration request end determination threshold APSth.

FIG. 3 is an example of a timing chart when the control device 12 executes the VVT control method of FIG.
As shown by the solid line in FIG. 3A, when the driver depresses the accelerator pedal and the detected value ΔAPS of the change rate of the accelerator opening becomes equal to or greater than the acceleration level determination threshold value ΔAPSth2, FIG. ) And (c), as indicated by solid lines, the target phase of the intake VVT is changed and set stepwise to the most advanced angle value, and the target phase of the exhaust VVT is changed and set stepwise to the most retarded angle value. Is done.

  On the other hand, as shown by the one-dot chain line in FIG. 3A, the driver depresses the accelerator pedal, and the detected value ΔAPS of the change rate of the accelerator opening is equal to or greater than the acceleration request determination threshold ΔAPSth1 and less than the acceleration level determination threshold ΔAPSth2. As shown in FIG. 3B and FIG. 3C, the target phase of the intake VVT is gradually changed toward the most advanced value as time elapses. The target phase is gradually changed toward the most retarded angle value.

  The torque (torque during sudden acceleration) when the detected value ΔAPS indicated by the solid line in FIG. 3D is equal to or greater than the acceleration level determination threshold ΔAPSth2 is the detected value indicated by the one-dot chain line in FIG. It is increased by ΔT as compared to the torque (torque during normal acceleration) when ΔAPS is equal to or greater than the acceleration request determination threshold ΔAPSth1 and less than the acceleration level determination threshold ΔAPSth2.

In the control device 12 of the internal combustion engine 10 of the first basic form described above, the second case where the detected value ΔAPS of the change rate of the accelerator opening is determined to be equal to or greater than the acceleration level determination threshold (second threshold) ΔAPSth2. Furthermore, the change rate (second change rate) is larger than the change rate (first change rate) in the first case where the detected value ΔAPS is equal to or greater than the acceleration request determination threshold value (first threshold value) ΔAPSth1 and less than the acceleration level determination threshold value ΔAPSth2. Change rate), the closing timing of the exhaust valve 35 is retarded, and the opening timing of the intake valve 34 is advanced. The rate of change can also be called the rate of change.

  Here, the first case is a case of normal acceleration, and the second case is a case of acceleration larger than normal acceleration (rapid acceleration). Therefore, according to this control device 12, in the case of rapid acceleration, the valve overlap period is rapidly increased as compared with normal acceleration. Further, due to the rapid increase in the valve overlap period, good scavenging efficiency is maintained even during rapid acceleration, and torque is improved.

In the control device 12 for the internal combustion engine 10 according to the first basic form described above, the valve timing control unit 74, in the second case, sets target values for the closing timing of the exhaust valve 35 and the opening timing of the intake valve 34 ( Since the phase target is changed stepwise to the optimum acceleration value, the valve overlap period is reliably increased rapidly.

(Second basic form)
Hereinafter, the second basic mode will be described. In the description of the embodiments described later, the same or similar configurations as those of the preceding basic embodiment are denoted by the same names or reference numerals, and the description thereof is omitted or simplified.

FIG. 4 schematically shows a functional configuration of the control device 80 of the second basic form. The control device 80 can also be applied to control the internal combustion engine 10.
The control device 80 includes a storage unit (storage unit) 82 that stores a plurality of map data for setting target values of various parameters. Specifically, the storage unit 82 includes, as map data, normal VVT map data (first valve phase map data) 84, sudden acceleration VVT map data (second valve phase map data) 86, and normal injection timing map data (first data). 1 injection timing map data) 88, sudden acceleration injection timing map data (second injection timing map data) 90, normal ignition timing map data (first ignition timing map data) 92, sudden acceleration ignition timing map data (second ignition timing) Map data) 94, normal A / F map data (first air-fuel ratio map data) 96, and rapid acceleration A / F map data (second air-fuel ratio map data) 98 are stored in advance.

FIG. 5 is a flowchart showing a schematic procedure of a VVT control method executed by the control device 80.
As shown in FIG. 5, in the first case where the detected value ΔAPS of the change rate of the accelerator opening is equal to or greater than the acceleration request determination threshold ΔAPSth1 and less than the acceleration level determination threshold ΔAPSth2, the control device 80 performs normal VVT map data 84. Is used to perform normal VVT control (S22) to control the opening / closing timing of the intake valve 34 and the exhaust valve 35. That is, the initial setting is such that the normal VVT map data 84 is used.
It should be noted that normal VVT control is performed using the normal VVT map data 84 even when the detected value ΔAPS of the change rate of the accelerator opening is less than the acceleration request determination threshold value ΔAPSth1.

  On the other hand, in the second case where the detected value ΔAPS of the change rate of the accelerator opening is equal to or greater than the acceleration level determination threshold value ΔAPSth2, the control device 80 executes the map data switching step S30, and suddenly changes the map data to be used from normal use to Switch to acceleration. Specifically, in the map data switching step S30, from the normal VVT map data 84 to the rapid acceleration VVT map data 86, from the normal injection timing map data 88 to the rapid acceleration injection timing map data 90, and from the normal ignition timing map data 92 The acceleration ignition timing map data 94 is switched from the normal A / F map data 96 to the rapid acceleration A / F map data 98.

  Then, the control device 80 performs VVT control for rapid acceleration using the rapid acceleration VVT map data 86 (S32), and controls the opening / closing timing of the intake valve 34 and the exhaust valve 35. Further, the control device 80 controls the fuel injection timing by the in-cylinder injection valve 42 using the rapid acceleration injection timing map data 90 while performing the VVT control for rapid acceleration, and the rapid acceleration ignition timing map data 94. Is used to control the ignition timing of the spark plug 44, and the rapid acceleration A / F map data 98 is used to control the fuel injection amount by the in-cylinder injection valve 42 and the opening of the throttle valve 54.

  Then, the control device 80 executes the map data switching step S34 when the detected value APS of the accelerator opening is less than the acceleration request end determination threshold APSth or when the acceleration time Tac exceeds the acceleration time determination threshold Tacth. Then, the map data to be used is switched from sudden acceleration to normal. Specifically, in the map data switching step S34, from the sudden acceleration VVT map data 86 to the normal VVT map data 84, from the sudden acceleration injection timing map data 90 to the normal injection timing map data 88, and from the sudden acceleration ignition timing map data 94. The normal ignition timing map data 92 is switched from the rapid acceleration A / F map data 98 to the normal A / F map data 96.

  Then, after the map data switching step S34, the control device 80 performs normal VVT control using the normal VVT map data 84 (S22) to control the opening / closing timing of the intake valve 34 and the exhaust valve 35. Further, the control device 80 controls the fuel injection timing by the in-cylinder injection valve 42 using the normal injection timing map data 88 while performing the normal VVT control, and uses the normal ignition timing map data 92, The ignition timing of the spark plug 44 is controlled, and the fuel injection amount by the in-cylinder injection valve 42 and the opening degree of the throttle valve 54 are controlled using the normal A / F map data 96.

FIG. 6 is an example of a timing chart when the control device 80 executes the VVT control method of FIG.
As shown by the solid line in FIG. 6A, when the driver depresses the accelerator pedal and the detected value ΔAPS of the change rate of the accelerator opening becomes equal to or greater than the acceleration level determination threshold value ΔAPSth2, FIG. ), (C), as indicated by solid lines, the target phase of the intake VVT is changed and set stepwise to the most advanced value using the sudden acceleration VVT map data 86, and the target phase of the exhaust VVT is set to the maximum. It is changed and set in steps to the retard value.

  On the other hand, as shown by the one-dot chain line in FIG. 6A, the driver depresses the accelerator pedal, and the detected value ΔAPS of the accelerator opening change speed is equal to or greater than the acceleration request determination threshold ΔAPSth1 and less than the acceleration level determination threshold ΔAPSth2. As shown in FIG. 6B and FIG. 6C, the normal VVT map data 84 is used, and the target phase of the intake VVT is changed to the most advanced value as time passes. The target phase of the exhaust VVT is gradually changed toward the most retarded value.

  Accordingly, the actual phase of the intake VVT in the second case where the detected value ΔAPS of the change rate of the accelerator opening, which is indicated by the solid line in FIG. 6E, is equal to or greater than the acceleration level determination threshold ΔAPSth2 is shown in FIG. ) Than the rate of change of the actual phase of the intake VVT in the first case where the detected value ΔAPS of the change rate of the accelerator opening, which is indicated by a one-dot chain line, is equal to or greater than the acceleration request determination threshold ΔAPSth1 and less than the acceleration level determination threshold ΔAPSth2 It changes at a large rate of change.

  Similarly, the actual phase of the exhaust VVT in the second case shown by the solid line in FIG. 6F is the change in the actual phase of the exhaust VVT in the first case shown by the dashed line in FIG. It changes at a rate of change greater than the rate.

Also, the fuel injection timing in the second case indicated by the solid line in FIG. 6G is delayed from the fuel injection timing in the first case indicated by the dashed line in FIG.
Furthermore, the ignition timing in the second case indicated by the solid line in FIG. 6 (h) is retarded from the ignition timing in the first case indicated by the one-dot chain line in FIG. 6 (h).

  The torque in the second case (torque during rapid acceleration) indicated by the solid line in FIG. 6D is the torque in the first case (torque during normal acceleration) indicated by the alternate long and short dash line in FIG. ) Is larger by ΔT.

In the control device 80 of the internal combustion engine 10 according to the second basic form described above, the second case where the detected value ΔAPS of the change rate of the accelerator opening is determined to be equal to or greater than the acceleration level determination threshold (second threshold) ΔAPSth2. Furthermore, the change rate (second change rate) is larger than the change rate (first change rate) in the first case where the detected value ΔAPS is equal to or greater than the acceleration request determination threshold value (first threshold value) ΔAPSth1 and less than the acceleration level determination threshold value ΔAPSth2. Change rate), the closing timing of the exhaust valve 35 is retarded, and the opening timing of the intake valve 34 is advanced.

  Therefore, according to this control device 80, in the case of rapid acceleration, the valve overlap period is rapidly increased compared with the case of normal acceleration. Further, due to the rapid increase in the valve overlap period, good scavenging efficiency is maintained even during rapid acceleration, and torque is improved.

In the control device 80 for the internal combustion engine 10 of the second basic form described above, the rapid acceleration VVT map data 86 is prepared in advance separately from the normal VVT map data 84, and the rapid acceleration VVT map data 86 is used in the second case. Thus, the valve overlap period can be reliably and rapidly increased.

Further, in the control device 80 for the internal combustion engine 10 of the second basic form described above, the rapid acceleration injection timing map data 90 is provided separately from the normal injection timing map data 88, the normal ignition timing map data 92, and the normal A / F map data 96. The rapid acceleration ignition timing map data 94 and the rapid acceleration A / F map data 98 are prepared in advance, and in the second case, the rapid acceleration injection timing map data 90, the rapid acceleration ignition timing map data 94, and the rapid acceleration A By using the / F map data 98, the torque during sudden acceleration can be further improved.

(First Embodiment)
The first embodiment will be described below.
FIG. 7 schematically shows a functional configuration of the control device 100 of the first embodiment together with the configuration of the internal combustion engine 10 that is a control target.

The internal combustion engine 10 of the first embodiment further includes a port injection valve (port fuel injection means) 43. The port injection valve 43 can inject fuel into the intake port 30. In addition, although not shown in figure, the fuel is supplied to the port injection valve 43 from a fuel via a feed pump.

On the other hand, the control device 100 does not include the acceleration time determination unit 80 but further includes a divided injection control unit (divided injection control unit) 102 and a port injection control unit (port injection control unit) 104.
The split injection control unit (in-cylinder injection control unit) 102 controls the injection amount and injection timing of the fuel injected from the in-cylinder injection valve 42 by controlling opening and closing of the in-cylinder injection valve 42.

In the present embodiment, the split injection control unit 102 determines that the detected value ΔAPS of the change rate of the accelerator opening is equal to or greater than the acceleration request determination threshold value ΔAPSth1 as soon as possible or simultaneously with the in-cylinder injection valve 42. To perform split injection.
On the other hand, when the detected value ΔAPS of the change rate of the accelerator opening is less than the acceleration request determination threshold value ΔAPSth1, the control device 80 causes the in-cylinder injection valve 42 to perform intake air injection.

Here, the intake air injection means that fuel is injected into the combustion chamber 28 during the intake stroke.
The split injection is to perform compression injection in which fuel is injected into the combustion chamber 28 in a compression stroke following the intake stroke after the intake injection is performed in the intake stroke. That is, split injection is a combination of intake injection and compression injection.

  The ratio of the fuel injection amount in the intake stroke and the fuel injection amount in the compression stroke in the split injection is set in advance. For example, the ratio of the fuel injection amount in the intake stroke and the fuel injection amount in the compression stroke is set to 7: 3. Further, the total injection amount of the fuel injected in the intake stroke and the compression stroke is determined by the control device 10 based on the detected value APS of the accelerator opening and the traveling state of the vehicle, as in the case of only the intake injection. Is done.

  In the internal combustion engine 10, the four strokes of the intake stroke, the compression stroke, the combustion stroke, and the exhaust stroke are repeated. With regard to the position of the piston 22, in the intake stroke, the piston 22 moves from the top dead center to the bottom dead center. In the compression stroke, the piston 22 is located from the bottom dead center to the top dead center.

  The port injection control unit 104 controls the injection amount and injection timing of the fuel injected from the port injection valve 43 by controlling opening and closing of the port injection valve 43. The port injection control unit 104 executes port injection for injecting fuel from the port injection valve 43 in parallel with intake injection or split injection performed by the in-cylinder injection valve 42 as necessary.

In split injection in which port injection is used together (port injection combined split injection), fuel is injected separately into port injection, intake injection, and compression injection. The total injection amount of fuel in the split injection with the port injection is based on the detected value APS of the accelerator opening and the traveling state of the vehicle, as in the case of only the intake injection and the case of only the split injection. Determined by.
For example, in split injection with port injection, the ratio of the fuel injection amount from the port injection valve 43 to the fuel injection amount from the in-cylinder injection valve is set to 7: 3.

  In the present embodiment, the port injection control unit 104 determines that the detected value ΔAPS of the change rate of the accelerator opening is greater than or equal to the acceleration request determination threshold ΔAPSth1 and less than the acceleration level determination threshold ΔAPSth2 as soon as possible or At the same time, the port injection valve 43 is caused to execute port injection. That is, in this embodiment, when it is determined that the detected value ΔAPS of the change rate of the accelerator opening is greater than or equal to the acceleration request determination threshold ΔAPSth1 and less than the acceleration level determination threshold ΔAPSth2, the port injection is performed as soon as possible or simultaneously. The combined injection (port injection combined injection) is executed.

  FIG. 8 is a flowchart schematically showing a procedure of the VVT / split injection control method executed by the control device 80.

  In the VVT / split injection control method, if the detection value ΔAPS is equal to or greater than the acceleration level determination threshold ΔAPSth2 as a result of the determination in the acceleration level determination step S12, the split injection on step S40 is executed and the split injection by the in-cylinder injection valve 42 is performed. Is started. Therefore, split injection is executed in a state where the valve opening timing of the intake valve 34 is set to the most advanced angle and the valve closing timing of the exhaust valve 35 is set to the most retarded angle. At this time, port injection by the port injection valve 43 is prohibited.

  As a result of the determination in the acceleration request end determination step S18, if the detected value APS of the accelerator opening is less than the acceleration request end determination threshold APSth, the divided injection off step S42 is executed, and the divided injection is stopped.

On the other hand, if the detection value ΔAPS is less than the acceleration level determination threshold ΔAPSth2 as a result of the determination in the acceleration level determination step S12, the port injection combined split injection on step S44 is executed, and the split injection and port injection by the in-cylinder injection valve 42 are performed. Port injection by the valve 43 is started.
If the detected value ΔAPS is less than the acceleration level determination threshold value ΔAPSth2, normal VVT control is executed (S46). Therefore, the port injection combined split injection is executed under normal VVT control.

  Then, after step S46, an acceleration request end determination step S48 is executed. As a result of the determination in the acceleration request end determination step S48, when the detected value APS of the accelerator opening is less than the acceleration request end determination threshold APSth, the port injection combined use divided injection off step S50 is executed, and the divided injection is stopped. After execution of the port injection combined split injection off step S50, the in-cylinder injection valve 42 executes intake air injection, and the port injection valve 43 stops port injection or changes the ratio of fuel to be injected as necessary. Above, port injection may continue.

FIG. 9 shows an example of a timing chart when the control device 100 executes the VVT / split injection control method of FIG.
As shown in FIG. 9 (i), if the detected value ΔAPS is equal to or greater than the acceleration request determination threshold value ΔAPSth1, the divided injection is turned on.

Then, as indicated by the solid line in FIG. 9 (j), when the detected value ΔAPS is equal to or greater than the acceleration level determination threshold ΔAPSth2, the port injection is prohibited and only the divided injection is executed. On the other hand, as indicated by a one-dot chain line in FIG. 9 (j), when the detected value ΔAPS is equal to or greater than the acceleration request determination threshold ΔAPSth1 and less than the acceleration level determination threshold ΔAPSth2, port injection is used together.
The port injection ratio is the ratio of the fuel injection amount injected from the port injection valve 43 to the total fuel injection amount injected from the in-cylinder injection valve 42 and the port injection valve 43.

According to the control device 100 of the first embodiment described above, when the detected value ΔAPS of the change rate of the accelerator opening is equal to or greater than the acceleration request determination threshold value ΔAPSth1, the divided injection is performed without using or using the port injection together. Executed. For this reason, acceleration performance is further improved.

According to the control device 100 of the first embodiment described above, when the change speed detection value ΔAPS is equal to or greater than the acceleration request determination threshold ΔAPSth1 and less than the acceleration level determination threshold ΔAPSth2, the split injection (first injection) Control mode) is executed, and only the split injection (second control mode) is executed when the acceleration level is equal to or higher than the acceleration level determination threshold.

In the first control mode, since port injection is used in parallel with in-cylinder injection, unburned components and the like contained in the exhaust gas are reduced. For this reason, according to the first control mode, environment-friendly control is possible while ensuring acceleration performance according to the driver's request.
On the other hand, in the second control mode, execution of port injection is prohibited and only in-cylinder injection is executed, so that even better acceleration performance can be obtained.

( Second Embodiment)
Hereinafter, a second embodiment will be described.
FIG. 10 schematically shows a functional configuration of the control device 110 according to the second embodiment. FIG. 11 is a flowchart showing a schematic procedure of the VVT / split injection control method executed by the control device 110.

As it is apparent from FIGS. 10 and 11 differs from the control unit 110 and the control unit 80 of the second embodiment differs from the control apparatus 100 of the first embodiment and the control unit 12 of the first basic mode It is the same as that, and it is a point which can perform division injection and division injection combined use division injection.

  That is, the control device 110 is configured to be able to execute the port injection combined split injection simultaneously with the normal VVT control when the change speed detection value ΔAPS is equal to or greater than the acceleration request determination threshold ΔAPSth1 and less than the acceleration level determination threshold ΔAPSth2. When the acceleration level determination threshold value ΔAPSth2 is equal to or higher, only the divided injection can be executed simultaneously with the acceleration VVT control.

According to the control device 110 of the second embodiment described above, when the detected value ΔAPS of the change rate of the accelerator opening is equal to or greater than the acceleration request determination threshold value ΔAPSth1, the divided injection is performed without using or using the port injection together. Executed. For this reason, acceleration performance is further improved.

According to the control device 110 of the second embodiment described above, when the change speed detection value ΔAPS is equal to or greater than the acceleration request determination threshold ΔAPSth1 and less than the acceleration level determination threshold ΔAPSth2, the split injection (first injection) is performed. Control mode) is executed, and only the split injection (second control mode) is executed when the acceleration level is equal to or higher than the acceleration level determination threshold.

In the first control mode, since port injection is used in parallel with in-cylinder injection, unburned components and the like contained in the exhaust gas are reduced. For this reason, according to the first control mode, environment-friendly control is possible while ensuring acceleration performance according to the driver's request.
On the other hand, in the second control mode, execution of port injection is prohibited and only in-cylinder injection is executed, so that even better acceleration performance can be obtained.

The present invention is not limited to the first and second embodiments described above, but includes forms obtained by modifying each of the first and second embodiments.
For example, in the first and second embodiments, the internal combustion engine 10 has the intake VVT mechanism 38 and the exhaust VVT mechanism 39, and the opening and closing timings of the intake valve 34 and the exhaust valve 35 are controlled. The opening / closing timing of only one of 34 and the exhaust valve 35 may be controlled. That is, it is only necessary to adjust the valve overlap period in which the valve opening timing of the intake valve 34 and the valve opening timing of the exhaust valve 35 overlap.

Further, for example, in the first and second embodiments, the port injection ratio may be changed according to the magnitude of the detected value ΔAPS of the change rate of the accelerator opening. Specifically, as the detected value ΔAPS of the change rate of the accelerator opening approaches the acceleration level determination threshold value ΔAPSth2, that is, as the detected value ΔAPS of the change rate of the accelerator opening becomes larger, the fuel injected by the port injection becomes larger. The ratio of the injection amount may be reduced.

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 12 Control apparatus 14 Crankcase 16 Cylinder block 18 Cylinder 22 Piston 26 Cylinder head 28 Combustion chamber 34 Intake valve 35 Exhaust valve 36 Intake cam 37 Exhaust cam 38 Intake VVT mechanism (Valve timing variable means)
39 Exhaust VVT mechanism (Valve timing variable means)
42 In-cylinder injection valve (in-cylinder fuel injection means)
43 Port injection valve (port fuel injection means)
44 Spark plug 64 Supercharger 66 Air flow sensor 68 Crank rotation angle sensor 69 Accelerator opening sensor 70 Acceleration request determination unit (determination means)
72 Acceleration level determination unit (determination means)
74 Valve timing control unit 76 Acceleration request end determination unit 78 Acceleration time determination unit

Claims (5)

Acceleration of the internal combustion engine having a supercharger, in-cylinder fuel injection means for directly injecting fuel into the combustion chamber, and valve timing variable means for adjusting at least one of the exhaust valve closing timing and the intake valve opening timing In the control apparatus for an internal combustion engine configured to increase a valve overlap period in which the exhaust valve closing timing and the intake valve opening timing overlap by the valve timing varying means,
A determination means for comparing a detected value of the change rate of the accelerator opening with a first threshold and a second threshold greater than the first threshold;
As a result of the comparison by the determination means, in the first case where the detected value is not less than the first threshold value and less than the second threshold value, the exhaust valve closing timing and the intake valve opening timing are controlled by the valve timing variable means. In the second case where at least one of them is changed at the first rate of change and the detected value is equal to or greater than the second threshold, the valve timing variable means causes the exhaust valve closing timing and the intake valve opening to be Valve timing control means for changing at least one of the times at a second rate of change greater than the first rate of change and increasing the valve overlap period;
In the second case, the valve timing control means sets the target value to the second change rate so that at least one target value of the exhaust valve closing timing and the intake valve opening timing becomes an acceleration optimum value. And change
The valve overlap period is increased when the latest detected value of the accelerator opening is less than the acceleration request end determination threshold or when the elapsed time from the acceleration request to the internal combustion engine exceeds the acceleration time determination threshold. It is configured to end valve timing control and shift to normal valve timing control ,
The control device includes split injection control means for performing split injection in which fuel is injected into the combustion chamber by the in-cylinder fuel injection means in both the intake stroke and the compression stroke, and the change rate of the accelerator opening is changed. When the detected value is less than a first threshold value, fuel is injected into the in-cylinder fuel injection means during the intake stroke, and the divided injection control means is caused to execute the divided injection in the first and second cases. A control device for an internal combustion engine characterized by the above. The internal combustion engine further includes port fuel injection means for performing port injection for injecting fuel into the intake port ,
In the second case, the control device prohibits the port injection in a state where the divided injection is performed, and executes the port injection in parallel with the divided injection in the first case. 2. The control apparatus for an internal combustion engine according to claim 1 , further comprising a port injection control means for causing the fuel injection to be performed.   In the second case, the valve timing control means is configured to stepwise change at least one target value of the exhaust valve closing timing and the intake valve opening timing to the acceleration optimum value. The control device for an internal combustion engine according to claim 1. First valve phase map data for setting a target value of at least one of the exhaust valve closing timing and the intake valve opening timing in the first case;
Second valve phase map data different from the first valve phase map data for setting at least one target value of the exhaust valve closing timing and the intake valve opening timing in the second case; 2. The control device for an internal combustion engine according to claim 1, further comprising storage means for storing. The storage means
First ignition timing map data for setting a target value of the ignition timing in the first case;
Second ignition timing map data different from the first ignition timing map data for setting the target value of the ignition timing in the second case;
First injection timing map data for setting a target value of the fuel injection timing in the first case;
The second injection timing map data different from the first injection timing map data for setting the target value of the fuel injection timing in the second case is further stored. 4. The control apparatus for an internal combustion engine according to 4 .

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