JP2009002284A - Control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine capable of moderating a change in intake pipe pressure in a transition state of an intake valve working angle, in the internal combustion engine for adjusting the intake air volume by changing the working angle of an intake valve. <P>SOLUTION: This invention is a device for controlling the internal combustion engine having a working angle variable mechanism capable of continuously varying the working angle of the intake valve, and has a target working angle determining means for determining a target working angle of the intake valve based on target torque or the target air volume, and a control means for controlling the working angle variable mechanism so as to coincide with the target working angle after changing by changing the working angle of the intake valve stepwise when changing the target working angle. The control means desirably changes the working angle stepwise so as not to change the working angle in a valve opening period of the intake valve. <P>COPYRIGHT: (C)2009,JPO&INPIT

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 internal combustion engine that includes a variable valve device that continuously varies the operating angle of an intake valve and can adjust the intake air amount by changing the intake valve operating angle. In such an internal combustion engine, when the intake valve operating angle is changed, the intake pipe pressure may change suddenly. When the intake pipe pressure changes suddenly, the internal EGR amount, the behavior of the fuel adhering to the wall surface, and the like change, and the air-fuel ratio in the cylinder tends to deviate from the target value. As a result, adverse effects such as deterioration of fuel consumption and acceleration shock (torque shock) may occur.

  Japanese Patent Application Laid-Open No. 2004-1000064 discloses a throttle opening (in which the throttle opening is increased when the actual intake pipe pressure deviates from the target intake pipe pressure so that the intake pipe pressure can be matched with the target intake pipe pressure). A technique is disclosed in which overshoot control is performed so that the throttle opening matches the reference target opening after the reference target opening) is overshot for a predetermined period.

JP 2004-1000064 A JP 2005-16316 A

  However, it is difficult to prevent the actual intake pipe pressure from deviating from the target intake pipe pressure with the conventional technique.

  The present invention has been made in view of the above points, and in an internal combustion engine that regulates the intake air amount by changing the operating angle of the intake valve, the intake pipe pressure change in the transient state of the intake valve operating angle is detected. An object of the present invention is to provide a control device for an internal combustion engine that can be made gentle.

In order to achieve the above object, a first invention is a control device for an internal combustion engine,
An apparatus for controlling an internal combustion engine provided with a working angle variable mechanism that continuously varies the working angle of an intake valve,
A target operating angle determining means for determining a target operating angle of the intake valve based on a target torque or a target air amount;
Control means for controlling the variable operating angle mechanism so that the operating angle of the intake valve is changed stepwise to match the changed target operating angle when the target operating angle is changed;
It is characterized by providing.

The second invention is the first invention, wherein
The control means is characterized in that the operating angle is changed stepwise so that the operating angle does not change during the opening period of the intake valve.

The third invention is the first or second invention, wherein
When the number of cylinders that share the operating angle variable mechanism is n, the control means changes the operating angle of the intake valve in n stages as the intake strokes of the cylinders come in sequence. It is characterized by.

According to a fourth invention, in any one of the first to third inventions,
A throttle valve disposed in the intake passage of the internal combustion engine;
The opening of the throttle valve is fed back so that the pressure downstream of the throttle valve becomes the target pressure between the time when the target operating angle is changed and the time when the operating angle of the intake valve matches the target operating angle. An intake pipe pressure control means for controlling;
It is characterized by providing.

According to a fifth invention, in any one of the first to fourth inventions,
Requested acceleration calculating means for calculating the requested acceleration;
Working angle change speed control means for increasing the speed until the working angle of the intake valve reaches the target working angle as the required acceleration is larger;
It is characterized by providing.

According to a sixth invention, in any one of the first to fifth inventions,
Acceleration shock detection means for detecting acceleration shock of the vehicle when the operating angle of the intake valve is changed;
An acceleration shock suppression means for limiting a change in the operating angle of the intake valve when an acceleration shock of a predetermined value or more is detected;
It is characterized by providing.

  According to the first aspect of the invention, when the target operating angle of the intake valve is changed, it is possible to control the operating angle of the intake valve to be changed stepwise so as to match the changed target operating angle. As a result, a sudden change in the intake pipe pressure accompanying a change in the intake valve operating angle can be reliably prevented, and a change in the intake pipe pressure can be moderated. For this reason, even when the intake valve operating angle is transient, fluctuations in the internal EGR amount and the behavior of the fuel adhering to the wall surface can be sufficiently suppressed, and the air-fuel ratio in the cylinder can be accurately controlled to the target value. . As a result, good fuel economy performance can be obtained, and the occurrence of acceleration shock (torque shock) can be reliably suppressed.

  According to the second aspect of the present invention, the intake valve operating angle can be changed stepwise so that the operating angle does not change during the opening period of the intake valve. As a result, even when the intake valve operating angle is in transition, the valve overlap amount of each cylinder can be accurately controlled, and the target combustion state can be reliably obtained. For this reason, more excellent characteristics in acceleration shock resistance, fuel consumption performance, emission performance, and the like can be obtained.

  According to the third aspect of the invention, when the number of cylinders sharing the operating angle variable mechanism is n, the operating angle of the intake valve is changed to n stages as the intake strokes of the cylinders come in sequence. be able to. For this reason, when changing the intake valve operating angle, the air amount of all the cylinders does not change all at once, but the air amount can be changed sequentially for each cylinder. Therefore, the change in the intake pipe pressure can be made more gentle, and the torques of all the cylinders can be changed sequentially for each cylinder instead of changing all at once. As a result, more excellent characteristics in acceleration shock resistance, fuel consumption performance, emission performance, and the like can be obtained.

  According to the fourth aspect of the present invention, the throttle valve is opened so that the pressure downstream of the throttle valve becomes the target pressure after the target operating angle is changed and before the operating angle of the intake valve matches the target operating angle. The degree can be feedback controlled. Thereby, the change of the intake pipe pressure can be more reliably suppressed in the transient state of the intake valve working angle. Therefore, particularly excellent characteristics in acceleration shock resistance, fuel consumption performance, emission performance, and the like can be obtained.

  According to the fifth aspect, as the required acceleration is larger, the speed until the operating angle of the intake valve reaches the target operating angle can be increased. For this reason, when the required acceleration is small, acceleration shock can be more reliably suppressed, and when the required acceleration is large, quick acceleration response can be obtained.

  According to the sixth invention, when the operating angle of the intake valve is changed, if a vehicle acceleration shock of a predetermined value or more is detected, the change of the operating angle of the intake valve can be limited. it can. For this reason, a sudden increase in torque can be suppressed, and the occurrence of an excessive acceleration shock can be more reliably suppressed.

Embodiment 1 FIG.
[System configuration]
FIG. 1 is a diagram for explaining a system configuration according to the first embodiment of the present invention. The system of Embodiment 1 includes a spark ignition type internal combustion engine 1 mounted on a vehicle as a power source. In the present invention, the number of cylinders and the cylinder arrangement of the internal combustion engine are not particularly limited, but in the present embodiment, the internal combustion engine 1 is assumed to be a V-type 6 cylinder. FIG. 1 shows only one of the cylinders.

  The internal combustion engine 1 includes a piston 3 and a cylinder block 4. The piston 3 is connected to the crankshaft 5 via a connecting rod. A crank angle sensor 6 is provided in the vicinity of the crankshaft 5.

  A cylinder head 8 is assembled to the upper part of the cylinder block 4. The cylinder head 8 is provided with a spark plug 11 that ignites the air-fuel mixture in the combustion chamber 10.

  The cylinder head 8 includes an intake port 12 that communicates with the combustion chamber 10. An intake valve 14 is provided at a connection portion between the intake port 12 and the combustion chamber 10. A variable operating angle mechanism 16 is provided for the intake valve 14. The operating angle variable mechanism 16 is configured to continuously change the operating angle of the intake valve 14 by rotating the control shaft 18. Although not shown, a worm wheel is fixed to one end portion of the control shaft 18, and a motor that rotationally drives a worm gear that meshes with the worm wheel is installed. The intake valve operating angle can be controlled by controlling the rotation amount of the motor by an ECU 50 described later.

  Further, in the present embodiment, although not shown, the intake valve 14 is further provided with a phase variable mechanism that continuously varies the phase of the intake camshaft. According to this phase variable mechanism, the valve opening phase of the intake valve 14 can be advanced or retarded.

  An intake passage 19 is connected to the intake port 12. A fuel injector 20 that injects fuel into the intake port 12 is provided in the vicinity of the intake port 12. The internal combustion engine 1 may include an in-cylinder injector that injects fuel directly into the cylinder instead of or together with the fuel injector 20.

  A surge tank 21 is provided in the middle of the intake passage 19. A throttle valve 22 is provided upstream of the surge tank 21. The throttle valve 22 is an electronically controlled throttle that is driven by a throttle motor 23. In the vicinity of the throttle valve 22, a throttle opening sensor 25 is provided for the opening of the throttle valve 22 (hereinafter referred to as “throttle opening”). An air flow meter 26 that detects the intake air amount Ga is provided upstream of the throttle valve 22. An air cleaner 27 is provided upstream of the air flow meter 26. An accelerator opening sensor 24 for detecting the accelerator pedal position is installed in the vicinity of the accelerator pedal.

  The cylinder head 8 includes an exhaust port 28 that communicates with the combustion chamber 10. An exhaust valve 29 is provided at a connection portion between the exhaust port 28 and the combustion chamber 10. An exhaust passage 30 is connected to the exhaust port 28. The exhaust passage 30 is provided with an air-fuel ratio sensor 31 that detects an exhaust air-fuel ratio. Further, the vehicle according to the present embodiment includes an acceleration sensor 32 for detecting the longitudinal acceleration of the vehicle and a select switch 34 for the driver to select a driving mode such as a power mode and an economy mode. .

  The system according to the present embodiment includes an ECU (Electronic Control Unit) 50. Various actuators and various sensors including the throttle valve 22 and the operating angle variable mechanism 16 are electrically connected to the ECU 50.

[Features of Embodiment 1]
FIG. 2 is a view for explaining how to change the intake valve working angle in the internal combustion engine 10 of the present embodiment. In FIG. 2, the upper diagram shows the timing of the exhaust stroke and the intake stroke of each cylinder. As shown in FIG. 2, the # 1, # 3, and # 5 cylinders of the internal combustion engine 10 that are V-type 6 cylinders are the right banks, and the # 2, # 4, and # 6 cylinders are the left banks. It is. The explosion order is # 1 → # 2 → # 3 → # 4 → # 5 → # 6. The operating angle variable mechanism 16 is provided separately in the left bank and the right bank. That is, in the internal combustion engine 10, # 1 cylinder, # 3 cylinder, and # 5 cylinder share one working angle variable mechanism 16, and # 2, # 4, and # 6 cylinders have another variable working angle. The mechanism 16 is shared.

  FIG. 2A shows an acceleration request. The ECU 50 detects an acceleration request based on the accelerator opening sensor 24 and the like. When the acceleration request is detected, the ECU 50 calculates a target torque (or target air amount), and further calculates a target value of the intake valve operating angle (hereinafter referred to as “target operating angle”) necessary to obtain the target torque. calculate. 2B and 2C, the target operating angles of the left bank and the right bank are indicated by broken lines, respectively.

  In the present embodiment, when the target operating angle is changed, the actual operating angle of the intake valve 14 (hereinafter referred to as “actual operating angle”) is not immediately followed, but the actual operating angle is changed stepwise. It was decided to match the target operating angle. In FIGS. 2B and 2C, the actual operating angles of the left bank and the right bank are indicated by solid lines, respectively. In this example, after the target operating angle is changed, the actual operating angle is changed in three stages so as to coincide with the changed target operating angle.

  According to the present embodiment, since the intake valve operating angle is changed stepwise as described above, a sudden change in the intake pipe pressure (pressure downstream of the throttle valve 22) accompanying the change in the intake valve operating angle is caused. This can be surely prevented and the intake pipe pressure change can be moderated. For this reason, fluctuations in the internal EGR amount and the behavior of the fuel adhering to the wall surface can be sufficiently suppressed, and the air-fuel ratio in the cylinder can be accurately controlled to the target value. As a result, good fuel economy performance can be obtained, and the occurrence of acceleration shock (torque shock) can be reliably suppressed.

  By the way, when the operating angle and the valve opening phase of the intake valve 14 are changed, the valve overlap amount between the intake valve 14 and the exhaust valve 29 (hereinafter simply referred to as “valve overlap amount”) also changes. The valve overlap amount has a great influence on the amount of air flowing into the cylinder, the amount of residual gas, the in-cylinder flow, and the like, and thus greatly affects the combustion state. For this reason, the target operating angle is set in consideration of the influence of the valve overlap amount.

  However, when the intake valve operating angle is changed, if the intake valve 14 is already open, that is, if it is already in the valve overlap state or has passed the valve overlap state, the valve of the combustion cycle The amount of overlap cannot be changed. For this reason, it becomes impossible to manage the combustion state by the valve overlap amount, which may adversely affect acceleration shock, fuel consumption, emission, and the like.

  Therefore, in the present embodiment, when the intake valve operating angle is changed stepwise, the intake valve operating angle is changed so that the operating angle does not change during the valve opening period of the intake valve 14. . This point will be described with reference to FIG.

  In the example shown in FIG. 2, when the target operating angle is changed, the # 5 cylinder is in the intake stroke. Even if the intake valve operating angle of the right bank is changed at this timing, the valve overlap amount of the # 5 cylinder cannot be changed. Therefore, in this case, the ECU 50 waits until the next cylinder # 6 reaches the intake stroke, and then changes the intake valve operating angle. That is, immediately before the intake stroke of the # 6 cylinder, the intake valve operating angle of the left bank is increased by one step ((1) in FIG. 2). Thereafter, immediately before the intake stroke of the # 1 cylinder, the intake valve operating angle of the right bank is increased by one step ((2) in FIG. 2). Next, just before the intake stroke of the # 2 cylinder, the intake valve operating angle of the left bank is increased by one more stage ((3) in FIG. 2), and then immediately before the intake stroke of the # 3 cylinder, the right bank Increase the intake valve working angle by one step ((4) in Fig. 2). Finally, immediately before the intake stroke of the # 4 cylinder, the intake valve operating angle of the left bank is further increased by one step so as to coincide with the target operating angle ((5) in FIG. 2). Just before the intake stroke, the intake valve operating angle in the right bank is further increased by one step to match the target operating angle ((6) in FIG. 2).

  According to the present embodiment, by changing the intake valve working angle at the timing as described above, it is possible to prevent the working angle from changing during the valve opening period of the intake valve 14. For this reason, even when the intake valve operating angle is transitional, the valve overlap amount of each cylinder can be accurately controlled, and a target combustion state can be reliably obtained. For this reason, more excellent characteristics in acceleration shock resistance, fuel consumption performance, emission performance, and the like can be obtained.

  Further, in the present embodiment, as shown in FIG. 2, the operating angle variable mechanism 16 in each of the left bank and the right bank has an intake valve as the intake strokes of the three cylinders under its control come sequentially. The operating angle is changed in three stages, the same as the number of cylinders. According to such control, when the intake valve operating angle is changed, the air amount of all the cylinders is not changed all at once, but the air amount can be sequentially changed for each cylinder. For this reason, the change in the intake pipe pressure can be further moderated, and the torque of all the cylinders can be changed sequentially for each cylinder rather than changing all at once. As a result, excellent characteristics in acceleration shock resistance, fuel consumption performance, emission performance, and the like can be obtained.

[Specific Processing in Embodiment 1]
Hereinafter, specific processing of the ECU 50 in the present embodiment will be described. 3 is a block diagram of the control system of the present embodiment, FIG. 4 is a block diagram of the power train manager in FIG. 3, and FIG. 5 is a routine executed by the ECU 50 to realize the above-described functions. It is a flowchart of.

  In the present embodiment, a map for determining the intake valve operating angle and the valve overlap amount (hereinafter collectively referred to as “valve system specifications”) in a steady state, a situation where fuel consumption should be optimized, It is decided to switch between situations where acceleration should be emphasized. According to the routine shown in FIG. 5, it is first determined which map should be selected based on the accelerator opening and the opening speed detected by the accelerator opening sensor 24 (step 100).

  In step 100, if the accelerator opening and the opening speed are equal to or less than the predetermined values, a valve operating map that optimizes fuel efficiency is selected (step 102). On the other hand, when the accelerator opening and the opening speed exceed the same predetermined values, a valve train map that emphasizes acceleration is selected (step 104).

  It should be noted that switching between the fuel efficiency optimal valve operating map and the acceleration-oriented valve operating map may be performed according to the select switch 34. For example, when the economy mode is selected, the optimal fuel consumption valve map may be selected, and when the power mode is selected, the acceleration-oriented valve map may be selected.

  Following the processing of step 102 or 104, the valve system specifications after reaching the steady state are set using the map selected from the optimal fuel efficiency valve map and the acceleration-oriented valve map. (Step 106). The fuel efficiency optimal valve map and the acceleration-oriented valve map are configured to calculate the target operating angle and the target valve overlap amount according to the target torque and the engine speed. The valve system parameters calculated by the acceleration-oriented valve map are those that emphasize acceleration compared to the fuel efficiency optimal valve map (for example, the intake valve operating angle is relatively large and the valve overlap amount is relatively small). Small).

  Subsequently, the estimated intake air amount Qvl after reaching the steady state is calculated and stored (step 108).

  Subsequently, the transient valve system parameters from the current valve system parameters to the transition to the valve system parameters after reaching the steady state calculated in step 106 are set (step 110). . In this step 110, the transient intake valve operating angle is set so as to satisfy the condition described above with reference to FIG.

  Subsequently, the operating angle variable mechanism 16 and the phase variable mechanism are driven based on the transient valve operating system specifications calculated in step 110 (step 112).

  Next, a method for controlling the throttle opening in the present embodiment will be described. In the present embodiment, the throttle valve 22 is driven prior to the intake valve operating angle so as to have an opening that allows a larger amount of air to be sucked by a predetermined amount than the intake air amount Qvl after reaching the steady state. FIG. 6 is a flowchart of a routine executed by the ECU 50 for controlling the throttle opening in the present embodiment.

  According to the routine shown in FIG. 6, first, the throttle valve passing air amount Qtg is calculated by adding a predetermined split increment α to the estimated intake air amount Qvl calculated in step 108 of the routine shown in FIG. (Step 120). Next, a throttle opening Tangle corresponding to the throttle valve passing air amount Qtg is calculated based on a predetermined map (step 122). Then, based on the calculated throttle opening Tangle, the throttle valve 22 is driven.

  In the present invention, the control method of the throttle valve 22 is not limited to such a method. For example, the throttle valve 22 may be fixed fully open.

  In the first embodiment described above, the ECU 50 executes the process of step 102 or 104 so that the “target operating angle determination means” in the first invention executes the processes of steps 110 and 112. By doing so, the "control means" in the first, second and third inventions is realized.

Embodiment 2. FIG.
Next, the second embodiment of the present invention will be described. The difference from the first embodiment will be mainly described, and the description of the same matters will be simplified or omitted.

  This embodiment is the same as Embodiment 1 described above except that the control method of the throttle opening in the transient state of the intake valve operating angle is different. In the present embodiment, the throttle opening is feedback-controlled so that the intake pipe pressure becomes the target value when the intake valve operating angle is in a transitional state that is changing toward the target operating angle. FIG. 7 is a flowchart of a routine executed by the ECU 50 at that time. In the present embodiment, the ECU 50 executes a routine shown in FIG. 7 instead of the routine shown in FIG. This routine is repeatedly executed every predetermined time.

  According to the routine shown in FIG. 7, it is first determined whether or not the intake valve operating angle is in a transient state (step 130). If it is determined that the intake valve operating angle is in a transient state, it is then determined whether or not the intake pipe pressure Pim detected by the intake pressure sensor is lower than the target lower limit intake pipe pressure Pimtl (step 132). ). In this embodiment, control is performed so that the intake pipe pressure Pim falls between the target lower limit intake pipe pressure Pimtl and the target upper limit intake pipe pressure Pimth. The target lower limit intake pipe pressure Pimtl and the target upper limit intake pipe pressure Pimth may be the same regardless of the target torque and the engine speed, and may be set based on a predetermined map according to the target torque and the engine speed.

  If the intake pipe pressure Pim is lower than the target lower limit intake pipe pressure Pimtl in step 132, the throttle opening Tangle is updated to a value larger than the current value by a predetermined change amount β (step 134). Then, the throttle valve 22 is driven based on the calculated throttle opening Tangle (step 140).

  On the other hand, if the intake pipe pressure Pim is equal to or higher than the target lower limit intake pipe pressure Pimtl in step 132, it is next determined whether or not the intake pipe pressure Pim exceeds the target upper limit intake pipe pressure Pimth. (Step 136). If the intake pipe pressure Pim exceeds the target upper limit intake pipe pressure Pimth, the throttle opening Tangle is updated to a value smaller than the current value by a predetermined change amount β (step 138). Then, the throttle valve 22 is driven based on the calculated throttle opening Tangle (step 140).

  If the intake pipe pressure Pim is equal to or lower than the target lower limit intake pipe pressure Pimtl in step 132, the intake pipe pressure Pim is already between the target lower limit intake pipe pressure Pimtl and the target upper limit intake pipe pressure Pimth. Will be. For this reason, in this case, the throttle opening degree Tangle remains the current value.

  According to the present embodiment described above, the change in the intake pipe pressure can be more reliably suppressed in the transient state of the intake valve operating angle. Therefore, particularly excellent characteristics in acceleration shock resistance, fuel consumption performance, emission performance, and the like can be obtained.

  In the second embodiment described above, the “intake pipe pressure control means” according to the fourth aspect of the present invention is realized by the ECU 50 executing the routine shown in FIG.

Embodiment 3 FIG.
Next, the third embodiment of the present invention will be described. The difference from the above-described first embodiment will be mainly described, and the description of the same matters will be simplified or omitted.

  In the present embodiment, the speed at which the intake valve operating angle is changed is increased as the required acceleration of the vehicle increases. Thus, as the required acceleration is larger, the intake valve operating angle can be set to the target operating angle earlier, so that quick acceleration responsiveness can be obtained.

  FIG. 8 is a flowchart of a routine executed by the ECU 50 in the present embodiment. In the present embodiment, the ECU 50 executes a routine shown in FIG. 8 instead of the routine shown in FIG. In the routine shown in FIG. 8, the same steps as those in the routine shown in FIG. 5 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  According to the routine shown in FIG. 7, first, in the same manner as the routine shown in FIG. 5, either the fuel efficiency optimal valve map or the acceleration-oriented valve map is selected (steps 100 to 104), and the selection is made. Based on the map, the valve system parameters after reaching the steady state are set (step 106).

  Subsequently, transient valve operating system specifications are set (step 150). At this time, in the present embodiment, the transient valve system specifications are determined so that the speed at which the intake valve operating angle is changed increases as the required acceleration increases. Here, to increase the speed at which the intake valve operating angle is changed, for example, to reduce the number of steps in the stepwise change of the intake valve operating angle until the target operating angle is reached, or to change the operating angle variable mechanism 16. It means increasing the rotational speed of the motor to be driven. Further, the required acceleration can be calculated based on the accelerator opening and the accelerator opening speed.

  When the transient valve system parameters are calculated in step 150, the operating angle variable mechanism 16 and the phase variable mechanism are driven based on the calculated values (step 112).

  According to the present embodiment described above, the speed at which the intake valve operating angle is changed can be changed according to the required acceleration. For this reason, when the required acceleration is small, acceleration shock can be more reliably suppressed, and when the required acceleration is large, quick acceleration response can be obtained.

  In the third embodiment described above, the ECU 50 calculates the required acceleration based on the accelerator opening and the accelerator opening speed, so that the “required acceleration calculating means” in the fifth aspect executes the processing of step 150. Thus, the “working angle change speed control means” in the fifth aspect of the invention is realized.

Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described, focusing on the differences from the above-described first embodiment, and description of similar matters will be simplified or omitted.

  In the present embodiment, in order to more reliably suppress acceleration shock when the intake valve operating angle changes, when the vehicle longitudinal acceleration detected by the acceleration sensor 32 exceeds a predetermined value, the intake valve operating angle We decided to limit the change.

  FIG. 9 is a flowchart of a routine executed by the ECU 50 in the present embodiment. In the present embodiment, the ECU 50 executes a routine shown in FIG. 9 instead of the routine shown in FIG. In the routine shown in FIG. 9, the same steps as those in the routine shown in FIG. 5 are denoted by the same reference numerals, and description thereof is omitted or simplified.

  According to the routine shown in FIG. 9, first, as in the routine shown in FIG. 5, either one of the optimal fuel consumption valve map and the acceleration-oriented valve map is selected (steps 100 to 104). Based on the map, the valve system parameters after reaching the steady state are set (step 106).

  Subsequently, the transient valve system specifications are set (step 160). At this time, in the present embodiment, as in the third embodiment described above, the transient valve operating system specifications are determined so that the speed at which the intake valve operating angle is changed increases as the required acceleration increases. Shall be. Of the transitional valve operating system specifications determined here, the transient target operating angle (the target operating angle in the middle stage) is defined as Vltg.

  Subsequently, it is determined whether or not an acceleration-oriented valve map is selected (step 162). In the present embodiment, when the fuel efficiency optimal valve operating map is selected, it can be estimated that there is no possibility of excessive acceleration shock, and the intake valve operating angle is not limited. Therefore, if it is determined in step 162 that the acceleration-oriented valve map is not selected, the operating valve variable mechanism 16 is used by using the transient valve system parameters calculated in step 160 as they are. Then, the phase variable mechanism is driven (step 112).

  On the other hand, if it is determined in step 162 that the acceleration-oriented valve map is selected, then whether the vehicle longitudinal acceleration G detected by the acceleration sensor 34 exceeds a predetermined allowable value A or not. Is determined (step 164). If the vehicle longitudinal acceleration G is less than or equal to the allowable value A in step 164, the operating angle variable mechanism 16 and the phase variable mechanism are determined by using the transient valve system parameters calculated in step 160 as they are. Driven (step 112).

  On the other hand, if the vehicle longitudinal acceleration G exceeds the allowable value A in step 164, the transient target operating angle Vltg is corrected to a value that is smaller by a predetermined limit amount B (step 166), and thereafter Then, the operating angle variable mechanism 16 and the phase variable mechanism are driven (step 112).

  According to the present embodiment described above, when the vehicle longitudinal acceleration G exceeds the allowable value A, a rapid increase in torque can be suppressed by suppressing an increase in the intake valve operating angle. For this reason, generation | occurrence | production of an acceleration shock can be suppressed more reliably.

  In the fourth embodiment described above, the acceleration sensor 34 corresponds to the “acceleration shock detection means” in the sixth aspect of the present invention. In addition, the “acceleration shock suppression means” according to the sixth aspect of the present invention is implemented by the ECU 50 executing the processing of steps 164 and 166 described above.

It is a figure for demonstrating the system configuration | structure of Embodiment 1 of this invention. It is a figure for demonstrating how to change the intake valve working angle in the internal combustion engine of embodiment of this invention. It is a block diagram of a control system of an embodiment of the present invention. FIG. 4 is a block diagram of a power train manager in FIG. 3. It is a flowchart of the routine performed in Embodiment 1 of the present invention. It is a flowchart of the routine performed in Embodiment 1 of the present invention. It is a flowchart of the routine performed in Embodiment 2 of this invention. It is a flowchart of the routine performed in Embodiment 3 of the present invention. It is a flowchart of the routine performed in Embodiment 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 6 Crank angle sensor 10 Combustion chamber 11 Spark plug 12 Intake port 14 Intake valve 16 Operating angle variable mechanism 19 Intake passage 20 Injector 22 Throttle valve 24 Accelerator opening sensor 25 Throttle opening sensor 26 Air flow meter 28 Exhaust port 30 Exhaust Passage 50 ECU

Claims (6)

An apparatus for controlling an internal combustion engine provided with a working angle variable mechanism that continuously varies the working angle of an intake valve,
A target operating angle determining means for determining a target operating angle of the intake valve based on a target torque or a target air amount;
Control means for controlling the variable operating angle mechanism so that the operating angle of the intake valve is changed stepwise to match the changed target operating angle when the target operating angle is changed;
A control device for an internal combustion engine, comprising:   2. The control apparatus for an internal combustion engine according to claim 1, wherein the control means changes the operating angle in a stepwise manner so that the operating angle does not change during the opening period of the intake valve.   When the number of cylinders that share the operating angle variable mechanism is n, the control means changes the operating angle of the intake valve in n stages as the intake strokes of the cylinders come in sequence. 3. The control device for an internal combustion engine according to claim 1, wherein the control device is an internal combustion engine. A throttle valve disposed in the intake passage of the internal combustion engine;
The opening of the throttle valve is fed back so that the pressure downstream of the throttle valve becomes the target pressure between the time when the target operating angle is changed and the time when the operating angle of the intake valve matches the target operating angle. An intake pipe pressure control means for controlling;
The control apparatus for an internal combustion engine according to any one of claims 1 to 3, further comprising: Requested acceleration calculating means for calculating the requested acceleration;
Working angle change speed control means for increasing the speed until the working angle of the intake valve reaches the target working angle as the required acceleration is larger;
The control device for an internal combustion engine according to any one of claims 1 to 4, further comprising: Acceleration shock detection means for detecting acceleration shock of the vehicle when the operating angle of the intake valve is changed;
An acceleration shock suppression means for limiting a change in the operating angle of the intake valve when an acceleration shock of a predetermined value or more is detected;
The control device for an internal combustion engine according to any one of claims 1 to 5, further comprising:

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