JP5045662B2 - Engine control device - Google Patents

Description

  The present invention relates to an engine control device, and more particularly to control of an intake air amount during deceleration.

  Conventionally, the intake air amount when the engine is decelerated is corrected based on the engine speed and the engine coolant temperature. On the other hand, there has been proposed a variable valve operating angle control device that variably controls the operation of valves such as an intake valve and an exhaust valve of an engine according to an operating state (Patent Document 1). In an engine equipped with such a device that variably controls the operation of the intake valve and the exhaust valve, it is desirable to correct the target intake air amount at the time of deceleration with an actually measured value (actual VVT value) of the valve timing of the intake valve.

JP 2007-162664 A

  By the way, when the target intake air amount at the time of deceleration is corrected by the VVT value, in the region where the engine load is small, the residual gas amount in the cylinder changes depending on the VVT value, and the range in which misfire occurs in the engine changes. Such misfires are more likely to occur as the VVT value is larger. Therefore, when the VVT value is large, the amount of intake air is increased to avoid misfire.

  In this way, the amount of intake air can be changed in accordance with the VVT value to avoid misfire during deceleration. However, during steady running after warm-up is completed, the displacement amount of the VVT value is large and The VVT return amount at the time of deceleration increases. As a result, the VVT return characteristic at the time of deceleration differs depending on the VVT value before the start of deceleration when decelerating from the steady running time. When the intake air amount at the time of deceleration is corrected with the actual VVT value, the deceleration characteristic depends on the VVT value before the deceleration. There is a problem that they are different.

  In the case of a hydraulic variable valve control device, VVT responsiveness after warm-up is fast, but hunting is likely to occur. If hunting occurs in the control valve opening / closing timing and correction is made with the actual VVT value, there is a problem that the intake air amount at the time of deceleration fluctuates and surging occurs.

  Therefore, in an engine that corrects the target intake air amount at the time of deceleration with the valve timing of the intake valve, it is an object to suppress a deceleration problem and surging due to a difference in valve timing.

  An engine control apparatus according to the present invention that solves such a problem includes a variable valve mechanism that makes at least the operation of an intake valve variable, an intake air adjustment valve that adjusts an intake air amount into an engine cylinder, and an engine coolant temperature. And a control means for controlling the opening degree of the intake air regulating valve, and the control means has a temperature measured by the temperature measurement means when the engine is decelerated is lower than T ° C. In the determination, the target intake air amount during deceleration is calculated based on the actual value of the valve opening / closing timing controlled by the variable valve mechanism, and the temperature measured by the temperature measuring means during engine deceleration is T ° C. When it is determined that the above is true, the target intake air amount at the time of deceleration is calculated and controlled based on the target value of the valve opening / closing timing controlled by the variable valve mechanism. To.

  By adopting such a configuration, misfire during deceleration is avoided and deceleration problems and surging are suppressed. In the hydraulic variable valve mechanism, the oil viscosity decreases due to warm-up, so that the response after warm-up becomes faster. Thereby, since the followability is good with respect to the target, there is no problem because it quickly converges to the target VVT without performing the deceleration Ga correction by the actual VVT value. As a result, it is possible to avoid the possibility of deceleration due to the actual VVT value difference and the possibility of hunting during deceleration. On the other hand, the cold variable operation of the hydraulic variable valve mechanism is slow in response due to high oil viscosity. Therefore, at the time of deceleration in the low temperature range, the deceleration Ga can be corrected with the actual VVT value to avoid misfire. Further, since the VVT response is slow at low temperatures, the possibility of hunting is low.

  In such an engine control device, when the control means determines that the engine coolant temperature is high when the engine is decelerating, the measured value of the valve opening / closing timing controlled by the variable valve mechanism and the target value are calculated. When it is determined that the difference is greater than or equal to the threshold value, the target intake air amount during deceleration can be calculated based on the actually measured value and controlled.

  By adopting such a configuration, it is possible to avoid misfire that occurs during deceleration when the responsiveness of the variable valve mechanism is significantly reduced.

  The engine control apparatus according to the present invention corrects the target intake air amount during deceleration based on the actual measured valve timing when the engine coolant temperature is low, and sets the target intake air amount during deceleration when the engine coolant temperature is high. By correcting based on the target map value of timing, the speed reduction is improved and surging is avoided.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of a control device 100 for the engine 1 of the present embodiment. The engine 1 is an in-cylinder injection type gasoline engine. The engine 1 includes a cylinder 2, a cylinder block 4 in which a water jacket 3 is formed, a piston 5 that reciprocates in the cylinder 2, and a crankshaft 7 that is connected to the piston 5 via a connecting rod 6.

  Furthermore, the engine 1 is provided with a cylinder head 10 in which an intake port 8 and an exhaust port 9 are formed. A combustion chamber 11 is formed by the cylinder 2, the piston 5, and the cylinder head 10. Further, the engine 1 is provided with a fuel injection valve 18 for injecting fuel into the combustion chamber 11 and a spark plug 19 for fuel ignition.

  An intake valve 12 is disposed at a connection portion between the intake port 8 and the combustion chamber 11, and air is taken into the combustion chamber 11 in accordance with the open / close state of the intake valve 12. An intake passage 15 in which a throttle valve 14 is installed is connected to the intake port 8. The throttle valve 14 is rotatably provided in the intake passage 15 and is drivingly connected to an actuator 16 formed of an electric motor or the like. The actuator 16 operates in response to a driver's depression operation of an accelerator pedal and the like, and rotates the throttle valve 14. The amount of air flowing through the intake passage 15 (intake air amount) varies according to the rotation angle (throttle opening) of the throttle valve 14.

  An exhaust valve 13 is disposed at a connection portion between the exhaust port 9 and the combustion chamber 11, and exhaust gas is discharged from the combustion chamber 11 in accordance with the open / close state of the exhaust valve 13. Connected to the exhaust port 9 is an exhaust pipe 17 provided with a catalyst device for exhaust purification.

  Next, a configuration for operating the intake valve 12 will be described. The intake valve 12 is urged by a valve spring in a direction that blocks communication between the intake port 8 and the combustion chamber 11, that is, a valve closing direction. An intake camshaft 20 having an intake cam 21 is provided on the upper side of the intake valve 12, that is, on the side opposite to the combustion chamber 11. The intake camshaft 20 rotates when the rotation of the crankshaft 7 is transmitted. With this rotation, the intake camshaft 20 opens the valve by pushing down the intake valve 12.

  The engine 1 is provided with a variable valve timing mechanism 41 and a variable operating angle mechanism 42 as variable valve mechanisms that change the valve characteristics of the intake valve 12. The variable valve timing mechanism 41 changes the relative rotation phase of the intake camshaft 20 with respect to the crankshaft 7 to keep the intake valve 12 open and close when the intake valve 12 is kept open. It is a mechanism that advances or retards the timing together. The working angle variable mechanism 42 is a mechanism that continuously varies the working angle of the intake valve 12 (see Japanese Patent Application Laid-Open No. 2007-162664). A drive mechanism similar to that of the intake valve 12 is also provided on the exhaust valve 13 side, and the valve opening period and operating angle of the exhaust valve 13 are variable.

  Further, the engine 1 includes a crank angle sensor 22, a rotation angle sensor 23, an air flow meter 24, a throttle sensor 25, and a water temperature sensor 26. Here, the rotation angle sensor 23 is a sensor that detects the rotation angle of the electric motor in the variable operating angle mechanism 42 in order to detect the valve characteristics (the operating angle and the maximum lift amount) of the intake valve 12. The water temperature sensor 26 is a sensor that detects the temperature of the engine coolant in the water jacket 3. The engine 1 also includes an ECU (Electronic Control Unit) 27. The ECU 27 is electrically connected to each of the crank angle sensor 22, the rotation angle sensor 23, the air flow meter 24, the throttle sensor 25, and the water temperature sensor 26, and acquires each information detected by each sensor.

  The ECU 27 is electrically connected to the actuator 16, the fuel injection valve 18, and the spark plug 19, and each device operates based on an electrical signal from the ECU 27.

  Next, control in the control device 100 of the engine 1 will be described. The operation control of the intake valve 12 by the variable control mechanism is performed based on the target VVT value. Here, the VVT value is an abbreviation for variable valve timing, and is a value indicating the advance angle of the valve opening period of the intake valve 12 that is changed by the variable valve mechanism. Calculation of the target VVT value is performed by the ECU 27.

  FIG. 2 is an explanatory diagram showing a map for calculating the target VVT value. FIG. 2A shows a map used at the engine cooling water temperatures T1 to T2, and FIG. 2B shows engine cooling. It is explanatory drawing which showed the map used at the time of water temperature T2-T3. As described above, the ECU 27 stores a plurality of different maps according to the range of the engine coolant temperature, and a part of the map is shown in FIG.

  The ECU 27 acquires the water temperature thw from the water temperature sensor 26, and selects a map to be used based on the acquired water temperature thw. The ECU 27 calculates the engine load from information acquired from the air flow meter 24 and the throttle sensor 25 and acquires the engine speed from the crank angle sensor 22. Then, the ECU 27 calculates the target VVT value by applying the calculated load of the engine 1 and the engine speed to the map of FIG.

  The ECU 27 controls the operation of the intake valve 12 by driving the variable valve mechanism based on the calculated target VVT value.

  Next, control of the target intake air amount when the engine 1 is decelerated will be described. The control device 100 of the present invention controls the target intake air amount when the engine 1 is decelerated by controlling the operation of the intake valve 12. This control is performed by the ECU 27.

  FIG. 3 is a control flow processed by the ECU in this embodiment. FIG. 4 is an explanatory diagram showing a map for calculating idle Ga in the flow of FIG. FIG. 5 is an explanatory diagram showing a map for calculating the rotation correction Ga in the flow of FIG.

  Hereinafter, the control by the ECU 27 will be described with reference to the flow of FIG. In step S11, the ECU 27 determines whether or not the engine 1 is decelerated. If the ECU 27 determines that the engine 1 is decelerated, the ECU 27 proceeds to step S12. In step S12, the ECU 27 acquires the water temperature thw and the engine speed NE, and calculates the target VVT value and the actual VVT value. Specifically, the ECU 27 acquires the water temperature thw from the water temperature sensor 26 and acquires the engine speed NE from the crank angle sensor 22. As described above, the ECU 27 calculates the target VVT value based on the map of FIG. Further, the ECU 27 calculates an actual VVT value from the cam angle calculated from the information acquired from the rotation angle sensor 23 and the crank angle acquired from the crank angle sensor 22. The ECU 27 proceeds to step S13 after completing the process of step S12.

  In step S13, the ECU 27 calculates idle Ga (Gai) using the map of FIG. Here, the idle Ga indicates a target intake air amount to be supplied into the cylinder during the idle operation. Specifically, the ECU 27 calculates the idle Ga by applying the engine cooling water temperature acquired by the water temperature sensor 26 to the map of FIG. After completing the process of step S13, the ECU 27 proceeds to step S14.

  In step S14, the ECU 27 determines whether or not the temperature of the engine cooling water is lower than T ° C. (0 ° C. in this embodiment). If the ECU 27 determines that the temperature of the engine coolant is below T ° C. (0 ° C. in the present embodiment), the ECU 27 proceeds to step S15.

  In step S15, the ECU 27 calculates a rotation correction Ga (Gane) based on the actual VVT value. Here, the rotation correction Ga indicates a correction amount of intake air based on each information of the engine coolant temperature, the engine speed, and the VVT value. Specifically, the ECU 27 calculates the rotation correction Ga (Gane) based on the VVT displacement amount at that time, that is, the actual VVT value and the engine speed NE.

  On the other hand, when the ECU 27 determines that the temperature of the engine cooling water is equal to or higher than T ° C. (0 ° C. in the present embodiment), the ECU 27 proceeds to step S16. In step S16, the ECU 27 calculates a rotation correction Ga (Gane) using the map of FIG. 5 based on the target VVT value. Specifically, the ECU 27 calculates the rotation correction Ga (Gane) by applying the VVT displacement amount at that time point, here, the target VVT value and the engine speed NE to the map of FIG.

After finishing the process of step S15, the ECU 27 proceeds to step S17. Further, after completing the process of step S16, the ECU 27 proceeds to step S17. In step S17, the ECU 27 calculates the deceleration Ga and controls the operations of the throttle valve 14 and the intake valve 12 so as to achieve the calculated deceleration Ga. Here, the deceleration Ga indicates a target intake air amount to be supplied into the cylinder during deceleration. The deceleration Ga is obtained by the following calculation formula.
Deceleration Ga = Gai + Gane (1)
The ECU 27 returns after completing the process of step S17.

  By the way, if ECU27 judges that the engine 1 is not decelerated by step S11, it will complete | finish a process and will return.

  As described above, the control device 100 corrects the target intake air amount during deceleration based on the actual VVT value when the engine coolant temperature is low, and corrects based on the map value of the target VVT when the engine coolant temperature is high. Thereby, the control apparatus 100 improves the deceleration property of the engine 1 and avoids misfire.

  Next, a second embodiment of the present invention will be described. The present embodiment is different from the first embodiment in that in addition to the control processing of the first embodiment, control for correcting the ignition timing at the time of deceleration is performed. The configuration of the cooling device of the present embodiment is the same as that of the first embodiment.

  FIG. 6 is a control flow processed by the ECU 27 in this embodiment. FIG. 7 is an explanatory diagram showing a map for calculating the ignition timing during idling in the flow of FIG. FIG. 8 is an explanatory diagram showing a map for calculating the rotation correction value of the ignition timing in the flow of FIG.

  Hereinafter, the control by the ECU 27 will be described with reference to the flow of FIG. In the flow of FIG. 6, the same steps as those in the flow of FIG. 3 are denoted by the same step numbers and description thereof is omitted.

  The ECU 27 performs processing from step S11 to step S13. When the ECU 27 finishes the process of step S13, the process proceeds to step S21.

  In step S21, the ECU 27 calculates idle SA (SAi) using the map of FIG. Here, the idle SA indicates the ignition timing during idle operation. Specifically, the ECU 27 calculates the idle SA (SAi) by applying the engine coolant temperature acquired by the water temperature sensor 26 to the map of FIG. After finishing the process of step S21, the ECU 27 proceeds to step S14.

  The ECU 27 proceeds to step S15 or step S16 based on the determination in step S14. When the ECU 27 proceeds to step S15, the ECU 27 proceeds to step S22 after completing the process of step S15.

  In step S22, the ECU 27 calculates a rotation correction SA (SAne) based on the actual VVT value. Here, the rotation correction SA indicates a correction value of the ignition timing based on each information of the engine coolant temperature, the engine speed, and the VVT value. Specifically, the ECU 27 calculates the rotation correction SA (SAne) based on the VVT displacement amount at that time, that is, the actual VVT value and the engine speed NE.

  On the other hand, when the ECU 27 proceeds to step S16, the ECU 27 proceeds to step S23 after completing the process of step S16. In step S23, the ECU 27 calculates a rotation correction SA (SAne) using the map of FIG. 8 based on the target VVT value. Specifically, the ECU 27 calculates the rotation correction SA (SAne) by applying the VVT displacement amount at that time, here, the target VVT value and the engine speed NE to the map of FIG.

After finishing the process of step S22, the ECU 27 proceeds to step S17. Further, after finishing the process of step S23, the ECU 27 proceeds to step S17. When the ECU 27 finishes the process of step S17, the process proceeds to step S24. In step S24, the ECU 27 calculates the deceleration SA, and controls the ignition timing so that the calculated deceleration SA is obtained. Here, the deceleration SA indicates the ignition timing during deceleration. The deceleration SA is obtained by the following calculation formula.
Deceleration SA = SAi + SAne (2)
The ECU 27 returns after completing the process of step S24.

  As described above, control device 100 corrects the ignition timing during deceleration based on the actual VVT value when the engine coolant temperature is low, and corrects based on the map value of target VVT when the engine coolant temperature is high. Thereby, the control apparatus 100 improves the deceleration property of the engine 1 and avoids misfire.

  Next, Embodiment 3 of the present invention will be described. The present embodiment is different from the first embodiment in that in addition to the control process of the first embodiment, control for correcting the air-fuel ratio at the time of deceleration is performed. The configuration of the cooling device of the present embodiment is the same as that of the first embodiment.

  FIG. 9 is a control flow processed by the ECU 27 in this embodiment. FIG. 10 is an explanatory diagram showing a map for calculating the deceleration target A / F in the flow of FIG. FIG. 11 is an explanatory diagram showing a map for calculating a correction coefficient for the deceleration target A / F in the flow of FIG.

  Hereinafter, the control by the ECU 27 will be described with reference to the flow of FIG. In the flow of FIG. 9, the same steps as those in the flow of FIG. 3 are denoted by the same step numbers, and the description thereof is omitted.

  The ECU 27 performs processing from step S11 to step S13. When the ECU 27 finishes the process of step S13, the process proceeds to step S31.

  In step S31, the ECU 27 calculates a deceleration target A / F (AFi) using the map of FIG. Here, the deceleration target A / F indicates the target air-fuel ratio at the time of deceleration when the valve timing is not advanced. Specifically, the ECU 27 calculates the deceleration target A / F (AFi) by applying the engine coolant temperature acquired by the water temperature sensor 26 to the map of FIG. After finishing the process of step S31, the ECU 27 proceeds to step S14.

  The ECU 27 proceeds to step S15 or step S16 based on the determination in step S14. When the ECU 27 proceeds to step S15, the ECU 27 proceeds to step S32 after completing the process of step S15.

  In step S32, the ECU 27 calculates a target A / F correction coefficient (AFne) based on the actual VVT value. Here, the target A / F correction coefficient is a correction coefficient for the target air-fuel ratio based on information on the engine speed and the VVT value. Specifically, the ECU 27 calculates a target A / F correction coefficient (AFne) based on the VVT displacement amount at that time, that is, the actual VVT value and the engine speed NE.

  On the other hand, when the ECU 27 proceeds to step S16, the ECU 27 proceeds to step S33 after completing the process of step S16. In step S33, the ECU 27 calculates a target A / F correction coefficient (AFne) using the map of FIG. 11 based on the target VVT value. Specifically, the ECU 27 calculates the target A / F correction coefficient (AFne) by applying the VVT displacement amount at that time point, here, the target VVT value and the engine speed NE to the map of FIG.

After finishing the process of step S32, the ECU 27 proceeds to step S17. Further, after finishing the process of step S33, the ECU 27 proceeds to step S17. When the ECU 27 finishes the process of step S17, the process proceeds to step S34. In step S34, the ECU 27 calculates the deceleration A / F and controls the air-fuel ratio so that the calculated deceleration A / F is obtained. The deceleration A / F is obtained by the following calculation formula.
Deceleration A / F = AFi x AFne (3)
The ECU 27 returns after completing the process of step S34.

  From the above, the control device 100 corrects the air-fuel ratio at the time of deceleration based on the actual VVT value when the engine coolant temperature is low, and corrects based on the map value of the target VVT when the engine coolant temperature is high. Thereby, the control apparatus 100 improves the deceleration property of the engine 1 and avoids misfire.

  Next, a fourth embodiment of the present invention will be described. The present embodiment is different from the first embodiment in that a countermeasure is taken when the responsiveness of the variable valve mechanism is significantly lowered during the execution of the control process of the first embodiment. The configuration of the cooling device of the present embodiment is the same as that of the first embodiment.

  FIG. 12 is a control flow processed by the ECU in this embodiment. In the control of this embodiment, when the difference between the actual VVT value and the target VVT value is large, the target intake air amount is corrected based on the actual VVT value, assuming that the responsiveness of the variable valve mechanism has deteriorated.

  Hereinafter, the control by the ECU 27 will be described with reference to the flow of FIG. In the flow of FIG. 12, the same steps as those in the flow of the first embodiment of FIG. 3 are denoted by the same step numbers, and the description thereof is omitted.

  The ECU 27 performs processing from step S11 to step S14. If the ECU 27 determines in step S14 that the temperature of the engine coolant is 0 ° C. or higher, the ECU 27 proceeds to step S41.

In step S41, the ECU 27 calculates a VVT displacement difference (ΔVT). Here, the VVT displacement difference is a difference between the actual VVT value and the target VVT value, and is expressed by the following equation.
ΔVT = actual VVT value-target VVT value (4)
When the ECU 27 finishes the process of step S41, the ECU 27 proceeds to step S42.

  In step S42, the ECU 27 determines whether ΔVT is less than a threshold value. Here, the threshold value is 10 ° CA, but other numerical values may be adopted.

  When the ECU 27 determines in step S42 that ΔVT is less than 10 ° CA, the ECU 27 proceeds to step S16. That is, the ECU 27 proceeds to a process of calculating the rotation correction Ga (Gane) using the map of FIG. 5 based on the target VVT value. On the other hand, if the ECU 27 determines in step S42 that ΔVT is 10 ° CA or more, the ECU 27 proceeds to step S15. That is, the ECU 27 proceeds to a process of calculating the rotation correction Ga (Gane) based on the actual VVT value.

  By performing the above control processing, the control device 100 avoids misfire that occurs during deceleration when the responsiveness of the variable valve mechanism is significantly reduced due to a failure or the like.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope.

It is explanatory drawing which showed schematic structure of the control apparatus of the engine of an Example. It is explanatory drawing which showed the map for calculating a target VVT value, Comprising: (a) shows the map used at the time of engine cooling water temperature T1, (b) is explanatory drawing which showed the map used at the time of engine cooling water T2. It is. It is the flow of control which ECU processes in Example 1. FIG. It is explanatory drawing which showed the map for calculating idle Ga in the flow of FIG. It is explanatory drawing which showed the map for calculating rotation correction Ga in the flow of FIG. It is a flow of control which ECU processes in Example 2. FIG. It is explanatory drawing which showed the map for calculating the ignition timing at the time of idling in the flow of FIG. It is explanatory drawing which showed the map for calculating the rotation correction value of ignition timing in the flow of FIG. 10 is a control flow processed by an ECU in the third embodiment. It is explanatory drawing which showed the map for calculating the deceleration target A / F in the flow of FIG. It is explanatory drawing which showed the map for calculating the correction coefficient of the deceleration target A / F in the flow of FIG. 9 is a control flow processed by an ECU in the fourth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 12 Intake valve 13 Exhaust valve 14 Throttle valve 18 Fuel injection valve 19 Spark plug 22 Crank angle sensor 23 Rotation angle sensor 24 Air flow meter 25 Throttle sensor 26 Water temperature sensor 27 ECU
41 valve timing variable mechanism 42 and working angle variable mechanism 100 control device

Claims (2)

A variable valve mechanism that makes at least the operation of the intake valve variable;
An intake air adjustment valve that adjusts the amount of intake air into the engine cylinder;
Temperature measuring means for measuring the coolant temperature of the engine;
Control means for controlling the opening of the intake air regulating valve;
With
When the control means determines that the temperature measured by the temperature measurement means is lower than T ° C. when the engine is decelerated, based on the actual value of the valve opening / closing timing controlled by the variable valve mechanism, the control means Calculate the target intake air amount,
The target intake air amount at the time of deceleration based on the target value of the valve opening / closing timing controlled by the variable valve mechanism when it is determined that the temperature measured by the temperature measuring means is equal to or higher than T ° C. during engine deceleration An engine control device that calculates and controls the engine. The engine control device according to claim 1,
When determining that the engine coolant temperature is high during deceleration of the engine, the control means determines that the difference between the measured value of the valve opening / closing timing controlled by the variable valve mechanism and the target value is equal to or greater than a threshold value. An engine control device that calculates and controls a target intake air amount during deceleration based on an actual measurement value.

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