JPH10299517A - Valve timing control device for on-vehicle internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve timing control device for an on-vehicle internal combustion engine capable of changing and controlling the valve timing in a condition suitably preventing damage of a clutch part in an automatic transmission. SOLUTION: In the case that a shift position by an automatic transmission 51 is in a first speed position, in a clutch part 52 thereof, a large load is inevitably applied, here, by a variable valve timing mechanism 30, so as to maximize torque of an engine 1, when valve timing change control is performed, sometimes damage is generated in the clutch part 52. Here, when a shift position by the automatic transmission 51 is decided to be the first speed, target valve timing is set to be corrected to a side of low torque without generating damage in the clutch part 52, based on this correction set target valve timing, valve timing of the engine 1 is controlled to be changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control system for a vehicle-mounted internal combustion engine for controlling the opening / closing timing of intake / exhaust valves provided in a cylinder of the vehicle-mounted internal combustion engine while the vehicle is running. .

[0002]

2. Description of the Related Art Conventionally, in an engine having such a valve timing control device, the valve timing is changed and controlled so as to obtain the maximum torque according to the operating state (speed and load) of the engine. Such valve timing change control is generally executed similarly even when an automatic transmission is mounted on a vehicle.

[0003]

By the way, in the above-mentioned automatic transmission which executes automatic shifting in a plurality of stages (for example, first to fourth speeds) according to the running state of the automobile, this is a low speed (first speed). When the state is switched to, a large load is inevitably applied to the clutch portion. Therefore, at this time, if the control for changing the valve timing is performed to obtain the maximum torque of the vehicle-mounted engine, the clutch unit may be damaged by the overload at that time. In order to prevent such damage to the clutch, (a) the clutch must be strengthened. (B) retarding the ignition timing of the engine; However, if the strength of the clutch part is increased, the manufacturing cost will increase.On the other hand, if the ignition timing of the engine is retarded, the exhaust temperature of the engine will increase and the reliability of the engine will increase. Another problem, such as lowering, may arise.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a valve of an on-vehicle internal combustion engine capable of controlling a valve timing to be changed so as to suitably prevent damage to a clutch portion in an automatic transmission. It is to provide a timing control device.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the invention according to claim 1 comprises a shift position detecting means for detecting a shift position of an automatic transmission mounted on an automobile,
An engine operating state detecting means for detecting an operating state of the internal combustion engine also mounted on the vehicle; a variable valve timing mechanism for varying a valve timing of the internal combustion engine; and the internal combustion engine according to the detected engine operating state. Target valve timing calculating means for calculating the target valve timing, and a valve for correcting the calculated target valve timing to a predetermined low torque timing when the detected shift position of the automatic transmission is a predetermined low speed shift position. Timing correction means, and valve timing change means for changing and controlling the valve timing of the internal combustion engine by operating the variable valve timing mechanism based on the calculated target valve timing or the corrected valve timing. It is an abstract.

According to the first aspect of the present invention, when the shift position detecting means detects that the shift position of the automatic transmission is a predetermined low-speed shift position, the valve timing correcting means sets the target valve timing. Is corrected to a predetermined low torque timing. Since the variable valve timing mechanism is operated by the valve timing changing means based on the corrected valve timing, the variable valve timing mechanism can be controlled to change the valve timing in a manner that suitably prevents the clutch portion of the automatic transmission from being damaged. it can.

Further, when the shift position detecting means detects that the shift position of the automatic transmission is other than the predetermined low-speed shift position, the correction to the predetermined low torque timing is not performed, and the target valve timing is not corrected. The variable valve timing mechanism is operated by the valve timing changing means. Therefore, the valve timing can be changed and controlled to maintain the maximum torque according to the operating state of the engine in each case.

According to a second aspect of the present invention, in the valve timing control apparatus for an on-vehicle internal combustion engine according to the first aspect, the valve timing correcting means may be configured such that the calculated target valve timing has a higher torque than a predetermined low torque timing. The gist is that the target valve timing is guarded at the predetermined low torque timing only when it is on the timing side.

According to the second aspect of the present invention, the structure for the above control is simple and can be easily put into practical use. Further, the control load as the control device can be minimized.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying a valve timing control apparatus for a vehicle-mounted internal combustion engine according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a system configuration diagram of an automobile multi-cylinder engine 1 as an on-vehicle internal combustion engine. The engine 1 includes a plurality of (only one is shown in FIG. 1) cylinders 2. A piston 3 movably provided in each cylinder 2 is provided with a rod 3 on a crankshaft 10 as an output shaft.
a. The upper side of the piston 3 in each cylinder 2 forms a combustion chamber 4. An ignition plug 11 provided for each combustion chamber 4 ignites the mixture introduced into the combustion chamber 4. Each of the intake port 5a and the exhaust port 6a provided corresponding to each combustion chamber 4 constitutes a part of the intake passage 5 and the exhaust passage 6. An intake valve 7 and an exhaust valve 8 provided corresponding to each combustion chamber 4
a and 6a are respectively opened and closed. Each of the valves 7 and 8 is connected to an intake camshaft 31 or an exhaust camshaft 32, respectively.
As the cam rotates, cams (not shown) provided on the shafts 31 and 32 rotate to open and close. Timing pulleys 33 and 34 provided at the tips of the camshafts 31 and 32 are connected to the crankshaft 10 via a timing belt 35 (the connection with the crankshaft 10 is not shown).

That is, when the engine 1 is operating, the rotational force of the crankshaft 10 is applied to each camshaft 3 via the timing belt 35 and the timing pulleys 33 and 34.
1, 32. As the camshafts 31 and 32 rotate, the valves 7 and 8 operate. Each of the valves 7, 8 is opened and closed at a predetermined timing in synchronization with the rotation of the crankshaft 10, that is, in response to the vertical movement of each piston 3.

A crank angle sensor 14 is provided close to the crankshaft 10, and detects the number of revolutions of the engine 1, the crank angle, the cylinder discrimination, and the like. A cam angle sensor 36 is provided near the camshaft 31, and detects the rotation angle and the like of the camshaft 31 (accordingly, the cam). Further, a water temperature sensor 15 for detecting the water temperature (cooling water temperature) THW of the cooling water of the engine 1 is attached to the cylinder block 1a.

An ignition voltage distributed by the distributor 12 is applied to the ignition plug 11 described above. The distributor 12 distributes the high voltage output from the igniter 13 to each spark plug 11 in synchronization with the crank angle of the engine 1.
The ignition timing of 1 is determined by the high voltage output timing from the igniter 13. Then, the engine 1 obtains a driving force by causing the aforementioned air-fuel mixture composed of the intake air from the intake passage 5 and the fuel injected from the injector 9 to explode in the combustion chamber 4 by the ignition plug 11 and obtain the driving force. The gas is discharged to the exhaust passage 6 via the exhaust valve 8.

A part of the intake passage 5 is provided with a surge tank 16 for suppressing the pulsation of the intake air, and a diaphragm-type intake pressure sensor 17 for detecting the intake pressure PM is mounted on the surge tank 16. I have. Surge tank 1
A throttle valve 18 that is opened and closed based on the operation of an accelerator pedal 21 is provided upstream of the throttle valve 6, and the amount of intake air to the intake passage 5 is adjusted by opening and closing the throttle valve 18. A throttle sensor 19 for detecting the throttle opening TA and an idle switch 20 that is turned on when the throttle valve 18 is fully closed are mounted near the throttle valve 18.

Further, an air cleaner 23 is disposed upstream of the throttle valve 18, and an air temperature sensor 24 for detecting an air temperature THA is mounted near the air cleaner 23.

In the exhaust passage 6, exhaust gas (HC,
Three-way catalytic converter 2 for purifying CO, NOx)
6 is attached. On the other hand, in the present embodiment, the engine 1 is provided with a variable valve timing mechanism (hereinafter referred to as “VVT mechanism”) 30 so as to be integrated with the intake camshaft 31 and the timing pulley 33. The VVT mechanism 30 is a known mechanism that changes the opening / closing timing of the valve 7 by changing the relative rotational phase between the camshaft 31 and the timing pulley 33 by the action of hydraulic pressure. That is, VV
The T mechanism 30 includes an advance-side hydraulic passage P1 that advances the relative rotation phase of the cam shaft with respect to the rotation of the timing pulley 33;
And a retard side hydraulic passage P2 for delaying the relative rotational phase. Further, the valve timing control device for operating the VVT mechanism 30 to change and control the valve timing of the engine 1 includes an oil pump 37 for supplying oil through both of the hydraulic passages P1 and P2, and the oil pump 37 and the hydraulic passages P1 and P2. An oil control valve (hereinafter, referred to as “OCV”) 38 is provided on the way. Each of the hydraulic passages P1 and P2 can be connected to an oil pan 40 via an OCV 38, an oil pump 37, and an oil strainer 39. When the oil pump 37 is driven with the operation of the engine, the oil stored in the oil pan 40 is sucked into the oil pump 37 via the oil strainer 39 and is pressurized by the pump 37. Is discharged. The discharged oil is selectively fed to the hydraulic passages P1 and P2 by the OCV 38. That is, by selectively switching the communication state between the oil pressure passages P1 and P2 and the oil pump 37 and the oil pan 40 by the OCV 38, the relative rotational phase between the camshaft 31 and the timing pulley 33 is changed. The opening / closing timing is changed.

Further, in this embodiment, the vehicle is provided with an automatic transmission 51. This automatic transmission 5
1 executes, for example, an automatic shift of the first to fourth speeds according to the driving state of the vehicle. Although the automatic transmission 51 is shown separately from the engine 1 for convenience in FIG. 1, in actuality, the crankshaft 10 and the torque converter 54 of the automatic transmission 51 are configured to be connected and released for driving. This is transmitted to the traveling of the automobile via the clutch section 52. A hydraulic control device 55 is provided in the automatic transmission 51, and the hydraulic control for the clutch unit 52 is performed by the device 55, and the automatic transmission according to the operation state is selectively executed. The transmission 51 is provided with a vehicle speed sensor 53 that protrudes into the transmission 51 and detects the speed of the vehicle.

Next, the configuration of an electronic control unit (hereinafter, referred to as "ECU") 61 for integrally controlling such an engine system will be described with reference to the block diagram of FIG. FIG.
As shown in FIG. 1, the ECU 61 is formed of a digital computer, and a RAM (random access memory) 63, a ROM (read only memory) 64, and a C
A PU (central processing unit) 65, an input port 66 and an output port 67 are provided.

The crank angle sensor 14 and the water temperature sensor 1
5, intake pressure sensor 17, throttle sensor 19, idle switch 20, intake air temperature sensor 24, cam angle sensor 36
And a detection signal from the vehicle speed sensor 53 or the like is supplied to an input port 66.
Is input to These sensors and the like 14, 15, 17, 1
The operating states of the engine 1 are detected by 9, 20, 24, and 36.

On the other hand, the output port 67 is connected to each injector 9, igniter 13,
It is connected to the OCV 38, the hydraulic control device 55, and the like.
Then, the ECU 61 determines each of the sensors 14, 15, 17, 1 and the like.
Based on signals from 9, 20, 24 and 36, the ROM 64
In accordance with a control program stored in the controller, the injector 9, the igniter 13, the OCV 38 (the VVT mechanism 30), the hydraulic control device 55 (the automatic transmission 51), and the like are suitably controlled.

Next, the operation of the engine system thus configured as a device for mainly performing the valve timing change control by operating the VVT mechanism 30 will be described, focusing on the processing by the ECU 61.

As described above, when the automatic transmission 51 is switched to a low speed position such as the first speed, a large load is inevitably applied to the clutch portion 52 thereof. At this time, when the valve timing change control is performed by the VVT mechanism 30 so that the maximum torque is obtained, a problem in durability occurs in the clutch portion 52.

Therefore, in the present embodiment, the valve timing of the engine 1 is changed and controlled by operating the VVT mechanism 30 in the following manner. FIG. 3 is a flowchart illustrating a valve timing change control routine of the engine 1 executed by the ECU 61. Note that this routine is periodically executed by a fixed time interruption every 8 ms (millisecond), for example.

When the processing shifts to this routine, the ECU
61 first calculates a provisional target advance value (provisional target valve timing) t_vvti in step 101. The provisional target advance value t_vvti is calculated by appropriately interpolating the map based on a map stored in the ROM 64 in advance, and as shown in FIG. It is calculated as an advance value (valve timing) at which torque is obtained.

In the next step 102, the ECU 61 having calculated the provisional target advance value t_vvti determines whether or not the shift position of the automatic transmission 51 is currently in the first speed. This is because when the ECU 61 executes automatic shifting based on the detection output of the vehicle speed sensor 53 and the like,
Reference is made to the control data for the hydraulic control device 55 of itself. If it is determined that the shift position of the automatic transmission 51 is not the first speed, the process proceeds to step 105, and the calculated temporary target advance value t_vvti is directly used as the target advance value (target valve timing) vvt. Set and exit this routine once.

On the other hand, if it is determined in step 102 that the current shift position of the automatic transmission 51 is the first speed, the process proceeds to step 103. And ECU
In step 103, the calculated provisional target advance value t_vvti is changed to a guaranteed advance value (guard value) t_ga in step 103.
It is determined whether or not rd or more. This guaranteed advance value t_gar
d is a fixed advance that guarantees the durability of the clutch unit 52 in the automatic transmission 51 when the valve timing control is performed through the VVT mechanism 30 when the shift position of the automatic transmission 51 is in the first speed. As shown in FIG. 4, the torque is smaller than the tentative target advance value t_vvti, and thus the obtained torque is set to a value smaller than the maximum torque (low torque timing). Here, when it is determined that the provisional target advance value t_vvti is smaller than the guaranteed advance value t_gard, step 10 is performed as described above.
5 and the calculated tentative target advance value t_vvti is calculated.
Is set as the target advance value vvt as it is, and the routine is temporarily exited.

On the other hand, if it is determined in step 103 that the provisional target advance value t_vvti is equal to or greater than the guaranteed advance value t_gard, the ECU 61 proceeds to step 104. Then, in step 104, the above-mentioned guaranteed advance value t_gard is set as the target advance value vvt, and the routine once exits.

The ECU 61 thereafter controls the duty control of the OCV 38 so that the target advance value vvt calculated in this way coincides with the actual advance value detected by the cam angle sensor 36 at each time. Is executed, the advance / retard control of the engine 1 through the VVT mechanism 30 is performed.

As described above, in this embodiment, when the shift position of the automatic transmission 51 is not at the first speed,
If the provisional target advance value t_vvti is within the range in which the durability of the clutch unit 52 in the automatic transmission 51 is guaranteed, that is, less than the guaranteed advance value t_gard, the advance value t_vvti is set to the target advance. As the angle value vvt,
The drive of the VVT mechanism 30 is controlled so that the maximum torque is obtained in the operating state of the engine 1 at that time.

On the other hand, the shift position of the automatic transmission 51 is at the first speed, and the provisional target advance value t_vvti is within the range in which the durability of the clutch 52 in the automatic transmission 51 is guaranteed, that is, the guaranteed advance value. When it is equal to or greater than t_gard, the guaranteed advance value t_gard is set to the target advance value vvt.
Thus, the drive of the VVT mechanism 30 is controlled so that the torque of the engine 1 does not damage the clutch portion 52.

As described in detail above, according to the present embodiment in which the valve timing control is performed in such a manner, the following effects can be obtained. When the shift position of the automatic transmission 51 is not in the first speed, or when the temporary target advance value t_vvti is in the range that guarantees the durability of the clutch unit 52 in the automatic transmission 51 even in the first speed. As usual, the maximum torque of the engine 1 is obtained.

If the shift position of the automatic transmission 51 is in the first speed and the provisional target advance value t_vvti is not within the range that guarantees the durability of the clutch unit 52 in the automatic transmission 51, Damage to the part 52 is preferably avoided.

The present embodiment is not limited to the above, but may be modified as follows. In the present embodiment, the above-mentioned guaranteed advance value t_gar
d is set on the retard side with respect to the temporary target advance value t_vvti. On the other hand, the guaranteed advance value t_gard may be set on the advance side of the provisional target advance value t_vvti.

In this embodiment, the automatic transmission 5
When the shift position by 1 is in the first speed and the provisional target advance value t_vvti is not within the range that guarantees the durability of the clutch unit 52 in the automatic transmission 51, the target advance value vvt is guaranteed to be the advance value. Although set to t_gard, it may be set to the most retarded value instead.

In this embodiment, the automatic transmission 5
When the shift position by 1 is in the first speed and the provisional target advance value t_vvti is not within the range that guarantees the durability of the clutch unit 52 in the automatic transmission 51, the target advance value vvt is guaranteed to be the advance value. Set to t_gard. On the other hand, when the shift position of the automatic transmission 51 is in the first speed, the target advance value vvt is directly used as the guaranteed advance value t_ga.
rd may be set. Further, the maximum retardation value may be set in the same manner as described above.

In this embodiment, the automatic transmission 5
When the shift position by 1 is in the first speed and the provisional target advance value t_vvti is not within the range that guarantees the durability of the clutch unit 52 in the automatic transmission 51, the target advance value vvt is guaranteed to be the advance value. Set to t_gard. On the other hand, when the shift position of the automatic transmission 51 is at an arbitrary low speed position, the guaranteed advance value for each of them may be specifically set.

In this embodiment, the automatic transmission 5
Although the automatic transmission 1 shifts between the first gear and the fourth gear, any number of gears may be used as long as the gear is a plurality of gears. Further, the automatic transmission 51 may have a structure that also performs other controls such as a direct coupling clutch control.

The VVT mechanism 30 is not limited to the intake-side camshaft 31, but may be provided on the exhaust-side camshaft 32 or on both the intake-side and exhaust-side shafts 31,32.

[0040]

As described above in detail, according to the first aspect of the present invention, when the shift position of the automatic transmission is detected to be a predetermined low-speed shift position by the shift position detecting means, The target valve timing is corrected to a predetermined low torque timing by the valve timing correction means. Since the variable valve timing mechanism is operated by the valve timing changing means based on the corrected valve timing, the variable valve timing mechanism can be controlled to change the valve timing in a manner that suitably prevents the clutch portion of the automatic transmission from being damaged. it can.

Further, when the shift position detecting means detects that the shift position of the automatic transmission is other than the predetermined low-speed shift position, the correction to the predetermined low torque timing is not performed and the target valve timing is not corrected. The variable valve timing mechanism is operated by the valve timing changing means. Therefore, the valve timing can be changed and controlled to maintain the maximum torque according to the operating state of the engine in each case.

According to the second aspect of the present invention, the structure for the above control is simple and can be easily put into practical use. Further, the control load as the control device can be minimized.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an outline of an engine system to which an embodiment of a valve timing control device according to the present invention is applied.

FIG. 2 is a block diagram showing an electrical configuration of the embodiment.

FIG. 3 is a flowchart showing a valve timing control procedure according to the embodiment;

FIG. 4 is a graph showing a relationship between a VVT advance angle and an engine torque.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine as an internal combustion engine, 5 ... Intake passage, 6 ... Exhaust passage, 14 ... Crank angle sensor, 15 ... Water temperature sensor,
17 ... intake pressure sensor, 19 ... throttle sensor, 20 ...
Idle switch, 24: intake air temperature sensor, 30: VVT
Mechanism, 36: cam angle sensor, 38: OCV, 51: automatic transmission, 52: clutch unit, 53: vehicle speed sensor, 54:
Torque converter, 55 hydraulic control device, 61 EC
U.

Claims (2)

[Claims] 1. A shift position detecting means for detecting a shift position of an automatic transmission mounted on an automobile; an engine operating state detecting means for detecting an operating state of an internal combustion engine also mounted on the automobile; A variable valve timing mechanism for varying the valve timing; target valve timing calculation means for calculating a target valve timing of the internal combustion engine according to the detected engine operating state; and a detected shift position of the automatic transmission. Valve timing correction means for correcting the calculated target valve timing to a predetermined low torque timing when the predetermined low-speed shift position is set; and the variable valve timing based on the calculated target valve timing or the corrected valve timing. A mechanism is operated to change and control the valve timing of the internal combustion engine. The valve timing control apparatus of the in-vehicle internal combustion engine, comprising a valve timing changing means. 2. The valve timing correction means according to claim 1, wherein the target valve timing is guarded at the predetermined low torque timing only when the calculated target valve timing is on a higher torque timing side than a predetermined low torque timing. The valve timing control device for a vehicle-mounted internal combustion engine according to claim 1, wherein