JPH07139380A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve follow-up of a variable valve timing mechanism (VVT) under speed change and to prevent worsening of acceleration owing to the switching delay of the VVT. CONSTITUTION:A car speed sensor 78 is electrically connected to an electronic control transmission electronic control unit (ECTECU) 62. When it is decided that the ECTECU 62 is under speed change, an execution signal is outputted to an electronic control unit (ECU) 80. As a result, control to a target value responding to an operation state is suspended by the ECU 80, an electromagnetic switching valve 47 is driven and the opening thereof is controlled to a specified value, and in an operation state at a point of time when speed change is completed, control is effected so that a maximum cam phase target value in a reverse direction to a direction in which the VVT 25 is moved by means of cam rotation torque is set as a target value. The opening closing timing of an intake valve 8 is varied to a most advance angle value and during speed change, valve overlap is controlled by means of a most advance angle value at the number of revolutions of an engine after speed change is completed.

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 device equipped with a variable valve timing mechanism for continuously changing the opening / closing timing of an intake valve or an exhaust valve according to the operating state of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in an engine having a variable valve timing mechanism, the variable valve timing mechanism performs a switching operation at a set engine speed. By this switching operation, the amount of overlap between the intake valve and the exhaust valve at the time of low rotation is made small, and at the time of high rotation, the amount of valve overlap is made large to improve torque characteristics and achieve high output.

By the way, in such an engine with a variable valve timing mechanism, there are the following problems in the upshift or downshift of the transmission. That is, if the engine speed suddenly changes over the set speed during upshifting or downshifting of the transmission, there is a problem that the valve timing control cannot follow this change. Therefore, the increase in the engine speed is delayed, the longitudinal acceleration of the vehicle is temporarily reduced, and the acceleration performance cannot be improved.

Particularly, in the type in which the variable valve timing mechanism is hydraulically controlled, it is necessary to fill the volume of the oil chamber with the movement of the piston by the amount of oil flowing into the system, so that the response tends to deteriorate. . Since the change of the cam phase target value is small in the normal operating state, the responsiveness does not become a problem except in the idling time when the amount of oil discharged from the oil pump is small. However, at the time of gear shift, the engine speed changes rapidly, and the cam phase target value changes rapidly accordingly.

In order to solve this problem, Japanese Patent Laid-Open No. 5-44
In the technology of No. 508, the variable valve timing mechanism has a map with a large or small overlap depending on the engine rotation, predicts the engine rotation speed after a shift, and switches the variable signal timing mechanism only for the time required for turning on and off. Is controlled in advance. This prevents deterioration of acceleration due to delay in switching of the variable valve timing mechanism.

[0006]

However, even if the above-mentioned technique is effective for a variable valve timing mechanism having a two-stage switching, the valve timing mechanism for continuously variably controlling a plurality of parameters is used. In this case, the target value of the cam phase changes from an arbitrary value to an arbitrary value, which makes control very difficult. That is, there is a problem in that the means for estimating the state after the end of the gear shift and the means for deciding the timing of outputting the switching command, which are provided in the above technique, are considerably complicated.

Further, since the variable valve timing mechanism of the two-stage switching has the valve timing switching, it suffices that the switching be surely completed after the shift is completed, and it is not necessary to terminate the control. On the other hand, in the variable valve timing mechanism that continuously changes, it is necessary to return the control to the normal control after the shift is completed, and this point cannot be solved by the above technique.

An object of the present invention is to improve the followability of the variable valve timing mechanism during shifting when continuously controlling the valve timing of the variable valve timing mechanism based on the engine speed of the internal combustion engine and the intake air amount. Accordingly, it is an object of the present invention to provide a valve timing control device for an internal combustion engine, which can prevent deterioration of acceleration performance due to switching delay of the variable valve timing mechanism.

[0009]

In order to solve the above-mentioned problems, the first invention is, as shown in FIG. 1, an intake valve M2.
And a variable valve timing mechanism M4 which is torsionally driven to continuously change the opening / closing timing of at least one of the exhaust valve M3, an operating state detecting means M5 for detecting the operating state of the internal combustion engine M1, and an operating state detection Valve timing determining means M6 for determining a valve timing target value based on the detection result of the means M5, and drive control means M7 for driving and controlling the variable valve timing mechanism M4 to control the opening / closing timing based on the valve timing target value. And a driving shift situation determining means M8 for determining whether or not a shift should be performed based on the detection result of the driving state detecting means M5, and the drive control means M7 shifts gears based on the determination result of the driving shift status determining means M8. During the period from the start to the end, the control to the target value according to the driving condition is stopped Variable valve timing mechanism M4 of the operating condition in which the subject matter to be controlled as a target value the maximum cam phase target value in the direction opposite to the direction of movement by the cam torque.

In the second aspect of the invention, the variable valve timing mechanism M4 is a hydraulic drive type, and the drive control means M7 is provided in the hydraulic system of the variable valve timing mechanism M4 from the start of shifting to the end thereof. The gist of the invention is to control the opening of a control valve that controls hydraulic pressure to a constant value.

[0011]

With the above construction, as shown in FIG. 1, the valve timing determination means M6 determines the valve timing target value based on the detection result of the operating state detection means M5 when the gear shift is not in progress. Then, the drive control means M7 drives and controls the variable valve timing mechanism M4 to control the opening / closing timing based on the valve timing target value.

When the driving gear shift situation judging means M8 judges that the gear shifting should be performed based on the detection result of the driving state detecting means M5, the drive control means M7 causes the driving gear shifting status judging means M8.
Based on the result of the determination, the control to the target value according to the operating state is stopped from the start of shifting to the end of shifting. Then, the drive control means M7 performs control with the maximum cam phase target value in the direction opposite to the direction in which the variable valve timing mechanism M4 moves with the cam rotation torque as the target value in the operating state at the end of the gear shift.

Further, in the second invention, drive control means M
Reference numeral 7 drives and controls a control valve opening degree for controlling the control hydraulic pressure provided in the hydraulic system of the variable valve timing mechanism M4 to a constant value from the start time to the end of the shift.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying a valve timing device for an internal combustion engine according to the present invention will be described below with reference to FIGS.

FIG. 2 is a schematic diagram showing a gasoline engine 1 as an internal combustion engine mounted on the vehicle of this embodiment (only one cylinder is shown). The engine 1 is provided with a piston 3 vertically movable within a cylinder 2 of each cylinder. The piston 3 is connected to a crankshaft (not shown) via a rod. The upper side of the piston 3 is the combustion chamber 4.

A spark plug 5 is provided in each combustion chamber 4. Further, an intake passage 6 and an exhaust passage 7 are provided in the combustion chamber 4 so as to communicate with each other. Combustion chamber 4 in intake passage 6
An intake valve 8 is attached to the intake port 6a opening to the. An exhaust valve 9 is attached to the exhaust port 7a of the exhaust passage 7 which opens to the combustion chamber 4. The intake valve 8 and the exhaust valve 9 are driven by the rotation of the intake camshaft 10 and the exhaust camshaft 11. An intake side timing pulley 12 and an exhaust side timing pulley 13 are provided at one end of each of the camshafts 10 and 11. Further, the timing pulleys 12 and 13 are drivingly connected to a crankshaft (not shown) via a timing belt 14.

Therefore, during operation of the engine 1, rotational power is transmitted from the crankshaft to the camshafts 10 and 11 via the timing belt 14 and the timing pulleys 12 and 13, and the intake air is generated by the rotation of the camshafts 10 and 11. The valve 8 and the exhaust valve 9 are opened and closed. The intake valve 8 and the exhaust valve 9 are synchronized with the rotation of the crankshaft. That is, it is driven at a predetermined opening / closing timing in synchronization with a series of four strokes including an intake stroke, a compression stroke, an explosion / expansion stroke, and an exhaust stroke.

Outside air is introduced into the intake passage 6 through an air cleaner 15. An injector 16 for fuel injection is provided in the intake passage 6 in the vicinity of the intake port 6a for each cylinder so that fuel is taken into the intake passage 6. As is well known, this injector 16
Is supplied with fuel at a predetermined pressure from a fuel tank (not shown) by the operation of a fuel pump. Then, the mixture of the fuel and the outside air, which is injected from the injector 16 and is taken into the intake passage 6, is passed through the intake port 6a and the combustion chamber 4 when the intake valve 8 is opened.
Be introduced to. In addition, when the air-fuel mixture introduced into the combustion chamber 4 is exploded and burned, the driving force of the engine 1 is obtained via the piston 3 and the crankshaft. Further, the burnt gas combusted in the combustion chamber 4 is discharged to the outside from the exhaust port 7a through the exhaust passage 7 when the exhaust valve 9 is opened.

A throttle valve 17 which is opened and closed in conjunction with the operation of an accelerator pedal (not shown) is provided in the middle of the intake passage 6. Then, by opening and closing the throttle valve 17, the amount of intake air into the intake passage 6 is adjusted. A surge tank 18 that smoothes the pulsation of the intake air amount is provided downstream of the throttle valve 17.

Further, an intake air temperature sensor 71 for detecting the intake air temperature THA is provided near the air cleaner 15 in the intake passage 6. Throttle valve 17
A throttle sensor 72 for detecting the throttle opening TA is provided in the vicinity of. Further, the surge tank 18 is provided with an intake pressure sensor 73 that communicates with the surge tank 18 and detects the intake pressure.

On the other hand, in the middle of the exhaust passage 7, a catalytic converter 1 having a built-in three-way catalyst for purifying exhaust gas.
9 is provided. Further, an oxygen sensor 74 for detecting the oxygen concentration in the exhaust gas is provided in the middle of the exhaust passage 7.

Further, the engine 1 is provided with a water temperature sensor 75 for detecting the temperature (cooling water temperature) THW of the cooling water. The spark plug 5 is a distributor 21.
Is driven based on the distributed ignition signal. In the distributor 21, the high voltage output from the igniter 22 is distributed to the spark plug 5 in synchronization with the crank angle of the engine 1. The ignition timing of each spark plug 5 is determined by the high voltage output timing from the igniter 22. The distributor 28 is provided with a rotor (not shown) that rotates in association with the rotation of the engine 1, and a rotation speed sensor 76 that detects the engine rotation speed NE from the rotation of the rotor. Further, the distributor 21 detects the crank angle reference position of the engine 1 at a predetermined ratio according to the rotation of the rotor,
A cylinder discrimination sensor 77 that outputs the reference signal GP is provided. In this embodiment, it is assumed that the crankshaft rotates twice for a series of four strokes of the engine 1.
The rotation speed sensor 76 detects the crank angle at a rate of 30 ° CA per pulse. The cylinder discrimination sensor 77 detects the crank angle at a rate of 360 ° CA per pulse.

In the intake passage 6 on the upstream side of the intake valve 8,
A bypass passage 23 that bypasses the throttle valve 17 and connects the upstream side and the downstream side of the valve 17 is provided. In the middle of this bypass passage 23, when the engine 1 is idling when the throttle valve 17 is fully closed,
A linear solenoid type idle speed control valve (ISCV) 24 for adjusting the intake air amount to stabilize the idling is provided. This IS
The opening degree of the bypass passage 23 and the like are adjusted by driving and controlling the CV 24 according to a predetermined signal.

Therefore, when the engine 1 is idling,
By controlling the opening degree of the ISCV 24 and its opening timing, the amount of air flowing through the bypass passage 23 is adjusted, and the amount of intake air to be supplied to the combustion chamber 4 is controlled.

The intake side timing pulley 12 has a variable valve timing mechanism (hereinafter simply referred to as "VV") which is hydraulically driven to change the opening / closing timing of the intake valve 8.
25).

Next, the structure of the VVT 25 and the like will be described. FIG. 3 is a sectional view showing the configuration of the VVT 25 and the like. The intake side camshaft 10 has its journal 10a.
Is rotatably supported by the cylinder head 31 and the bearing cap 32 of the engine 1. A cylindrical fixed gear 33 is fastened and fixed to the front end of the camshaft 10 with a bolt 34. A timing pulley 35 is rotatably provided on the outer periphery of the front end of the camshaft 10. The front end of the boss portion 36 of the timing pulley 35 is loosely inserted between the fixed gear 33 and the outer circumference of the cam shaft 10, and the rear end of the boss portion 36 slidably contacts the flange 10b protruding from the outer circumference of the cam shaft 10. It is touched.

The timing belt 35 is mounted on the timing pulley 35, and the rotation of a crankshaft (not shown) is transmitted to the timing pulley 35 via the timing belt 14. A cap 38 is fastened and fixed to the front end surface of the timing pulley 35 with a bolt 39. The cap 38 covers the front end of the camshaft 10. The bolt 3 is provided between the timing pulleys 35.
A tubular gear 40, which is fastened and fixed at 9, is arranged. The timing pulley 35, gear 40, cap 3
A space surrounded by 8 is an annular space 41, and a ring gear 42 having a substantially double-cylindrical shape is arranged in the annular space 41. The timing pulley 35 and the fixed gear 33 are drivingly connected by the ring gear 42. That is, helical splines 42a and 42b are formed on the outermost circumference and the innermost circumference of the ring gear 42, respectively. On the other hand, helical splines 33a and 40a are formed on the outer periphery of the rear end of the fixed gear 33 and the inner periphery of the gear 40. The helical splines 42a, 40a mesh with each other, and the helical splines 42b, 33a.
The two are in mesh with each other.

Therefore, when the rotation of the crankshaft is transmitted to the timing pulley 35 via the timing belt 14, the timing pulley 35 and the fixed gear 33 connected by the ring gear 42 are integrally rotated, and the camshaft 10 is rotated. It is driven to rotate.

Ring gear 42 in the annular space 41
The front side of is a first pressure chamber 43, and the rear side of the ring gear 42 is a second pressure chamber 44. This pressure chamber 43,
Hydraulic oil is supplied to 44. That is, an advance angle control passage 45 is formed in the front end portion of the camshaft 10, the boss portion 36 of the timing pulley 35, and the cylinder head 31. Advance side control passage 4 in the camshaft 10
One end of 5 is connected to the second pressure chamber 44 through the opening of the boss 36.
And the other end communicates with an opening 45a provided at the center of the cam journal portion 10a in the width direction. The opening 45a communicates with the advance angle control passage 45 on the cylinder head side, which opens in the bearing portion of the cylinder head 31.

Further, the front end portion of the camshaft 10, the bolt 34, and the cylinder head 31 are provided with a retard control passage 46.
Are formed. That is, one end of the retard side control passage 46 in the camshaft 10 is communicated with the first pressure chamber 43 through the through hole 34a formed along the axial center of the bolt 34, and the other end is in the cam journal portion. It communicates with an opening 46a provided on the thrust surface side of 10a. The opening 46a communicates with the advance angle control passage 46 on the cylinder head 31 side, which opens in the cam journal 10a in the bearing portion of the cylinder head 31.

The advance control passage 45 and the retard control passage 4
6 is an electromagnetic switching valve 47 as a control valve, an oil pump 48
Is connected to the oil pan 49 via. The oil pump 48 is drivingly connected to the crankshaft of the engine 1, pumps up the hydraulic oil in the oil pan 49 in conjunction with the operation of the engine 1, and advances the passage 45 for controlling the advance angle selected by the electromagnetic switching valve 47. Alternatively, it is supplied to one of the hydraulic chambers via the retard control passage 46. Due to this supply, hydraulic pressure acts on the ring gear 42.

The electromagnetic switching valve 47 is a 4-port 3-position type linear solenoid valve, and the electromagnetic portion 47
a and the pressure regulating valve 47b are integrated. Electromagnetic part 47
The spool (not shown) a generates a load in the direction of contracting the spring of the pressure adjusting portion (not shown) of the pressure adjusting valve 47b according to the current value.
The hydraulic pressure is generated so as to oppose the load a, and the hydraulic pressure proportional to the magnitude of the current is obtained. And
Excitation / demagnetization of the electromagnetic portion 47a of the electromagnetic switching valve causes switching operation to three positions of a neutral position, a retard control position and an advance control position. That is, when the electromagnetic switching valve 47 is located at the neutral position, the advance / retard control passage 4
The supply of hydraulic oil to 5, 46 is stopped together. When the electromagnetic switching valve 47 is located in the retard control position, the retard control passage 46 serves as a hydraulic oil supply passage to the first pressure chamber 43, and the advance control passage 45 extends from the second pressure chamber 44. It is a return path for returning the hydraulic oil to the oil pan 48.
Further, when the electromagnetic switching valve 47 is located in the advance angle control position, the advance angle control passage 45 serves as a hydraulic oil supply passage to the second pressure chamber 44, and the retard angle control passage 46 forms the first pressure chamber. Four
3 is a return path from which hydraulic oil is returned to the oil pan 49.

The electromagnetic switching valve 47 is electrically connected to an electronic control unit (engine ECU) 80 for controlling its operation. When the electromagnetic switching valve 47 is actuated to the retard control position based on the control signal from the engine ECU 80, the hydraulic oil is allowed to be supplied to the retard control passage 46, and the hydraulic oil is supplied to the retard control passage 46. Is introduced into the first pressure chamber 43. Then, the hydraulic pressure presses the ring gear 42 in one axial direction (to the right in FIG. 3). As a result, the camshaft 10 is twisted and the gear 40
The rotational phase of and is out of phase. That is, the opening / closing of the intake valve 8 is delayed, and the valve overlap between the intake valve 8 and the exhaust valve 9 in the intake stroke is reduced.

On the contrary, when the electromagnetic switching valve 47 is operated to the advance control position based on the control signal from the engine ECU 80, the supply of the hydraulic oil to the advance control passage 45 is permitted, and the hydraulic oil advances the advance angle. From the control passage 45 to the second pressure chamber 44
Will be introduced to. Then, due to the oil pressure, the ring gear 42
Is pressed in one axial direction (leftward in FIG. 1). As a result, the camshaft 10 is twisted in the opposite direction to the above, and the rotational phase with the gear 40 is deviated. That is, the opening / closing of the intake valve 8 is accelerated, and the valve overlap between the intake valve 8 and the exhaust valve 9 in the intake stroke is increased.

The VVT 25 is constructed as described above,
By driving the VT 25, the opening / closing timing of the intake valve 8 and, by extension, the valve overlap between the intake valve 8 and the exhaust valve 9 has the magnitude shown in FIG.
The size can be changed continuously between the sizes shown in (b).

Further, since the VVT 25 opposes the cam drive torque, the second pressure chamber 44, which is always on the advance chamber side by the pressure regulation of the electromagnetic switching valve 47 in the intermediate holding state, is on the retard chamber side. Is kept higher than that of the pressure chamber 43, and the responsiveness on the “advance side → retard side” is better than the responsiveness on the “retard side → advance side”.

As shown in FIG. 2, the injector 16, the igniter 22, the ISCV 24, and the electromagnetic switching valve 47 are electrically connected to the engine ECU 80, and the drive timing of these is controlled by the operation of the engine ECU 80. In this embodiment, the engine ECU 80 constitutes valve timing determination means and drive control means. The intake air temperature sensor 71, the throttle sensor 72, the intake air pressure sensor 73, the oxygen sensor 74, the water temperature sensor 75, the rotation speed sensor 76, and the cylinder discrimination sensor 77 are connected to the engine ECU 80.

The engine ECU 80 uses these sensors 71.
Based on the output signals from ~ 77, each injector 16, igniter 22, ISCV 24, and electromagnetic switching valve 47 are suitably driven and controlled. Further, in this embodiment, the throttle sensor 72, the intake pressure sensor 73, the rotation speed sensor 76 and the like constitute an operating condition detecting means for detecting an operating condition of the engine 1 necessary for controlling the valve timing.

Next, the electrical configuration of the engine ECU 80 will be described with reference to the block diagram of FIG. The engine ECU 80 includes a central processing unit (CPU) 81, a read-only memory (RO) in which a predetermined control program and the like are stored in advance.
M) 82, a random access memory (RAM) 83 for temporarily storing the calculation result of the CPU 81, a backup RAM 84 for storing previously stored data, and the like, these units, an external input circuit 85, an external output circuit 86, etc.
It is configured as a logical operation circuit connected by 7.

The intake air temperature sensor 71, the throttle sensor 72, the intake air pressure sensor 73, the oxygen sensor 74, the water temperature sensor 75, the rotation speed sensor 76, and the cylinder discrimination sensor 77 are connected to the external input circuit 85, respectively. On the other hand, the external output circuit 47 includes an injector 16 and an igniter 2
2, the ISCV 24 and the electromagnetic switching valve 47 are connected to each other.

Then, the CPU 81 reads the detection signals of the sensors 71 to 77, etc., inputted via the external input circuit 85, as input values. Further, the CPU 81 has each sensor 71 to
In order to execute fuel injection amount value control, ignition timing control, idle rotation control, valve timing control, or the like based on the input value read from 77, each injector 1
6, igniter 22, ISCV24 and electromagnetic switching valve 47
And the like are controlled appropriately.

The throttle sensor 72, the intake pressure sensor 73, the rotation speed sensor 76, the water temperature sensor 75, and the cylinder discrimination sensor 77 described above constitute an operating state detecting means for detecting the operating state of the engine 1. Further, in this embodiment, a vehicle speed sensor 78 for detecting the traveling speed (vehicle speed) SP of the vehicle is provided. The vehicle speed sensor 78 detects the rotation speed No (output shaft rotation speed) of the gear on the output shaft side of the automatic transmission 61, and constitutes a driving state detecting means. Further, the automatic transmission 61 is provided with an input speed sensor 79 for detecting the rotation speed Nt (input shaft rotation speed) on the input shaft side.

As described above, the engine ECU 80 is a device that controls valve timing control, fuel injection control, and ignition timing control. In addition to this, the electric controlled transmission electronic control unit (ECTEC)
U) 62 is provided. That is, the engine 1 is connected to an overdrive four-speed automatic transmission 61 with a direct coupling clutch for switching the speed change state. The ECT ECU 62 controls the direct coupling clutch control and the shift control in the automatic transmission 61. Therefore, a shift position sensor 63, which is provided in the gear shift mechanism of the automatic transmission 61 and detects the shift position Psift, is electrically connected to the input side of the ECT ECU 62. An actuator (not shown) incorporated in the automatic transmission 61 is electrically connected to the output side of the ECT ECU 62.

Further, the ECT ECU 62 is an engine EC
Data signals are exchanged with U80. The ECT ECU 62 is the engine ECU 8
0 to the intake pressure sensor 73 and each sensor 72, 75, 76
In addition to reading data values such as detection values and calculation results, the detection values of the shift position sensor 63 are read, and the automatic transmission 61 is suitably controlled according to the shifting conditions at that time. A shift-up pattern is selected from a ROM (not shown) according to the state of the shift position, and the throttle opening TA and the vehicle speed S at that time are selected based on the determined pattern.
The gear shift operation is performed according to P. The vehicle speed sensor 78 and the input speed sensor 79 are electrically connected to the input side of the ECT ECU 62.

The ECT ECU 62 is also the engine E.
Similar to the CU80, a central processing unit (CPU), a read only memory (ROM), and a read / write rewritable memory (R
(AM) etc., and constitutes a driving speed change status judging means.

Now, the operation of the valve timing control system for an internal combustion engine constructed as described above will be described with reference to FIGS. 5 and 7 to 9. Fig. 7 shows V when shifting up
8 is a flowchart of a VVT control routine executed by the ECT ECU 62 and the engine ECU 80 to drive and control the VT 23, which is executed by a regular interrupt every predetermined time. Before entering this control routine, these detection values are stored in the RAM of each ECU based on the detection signals from the various sensors input at each time.

In this routine, the ECT ECU 62 first determines in step 101 the cooling water temperature THW and the throttle opening TA.
It is determined whether or not the control satisfaction conditions are satisfied or not, and if the control satisfaction conditions are not satisfied, the subsequent processing is temporarily stopped and the control routine is exited. If the condition for control is satisfied, E
The CTECU 62 determines in step 102 whether or not the upshift is being performed, based on the throttle opening TA and the vehicle speed SP. This determination is made based on the shift position detection signal from the shift position sensor 63 by reading a map corresponding to the shift position at that time, for example, as shown in FIG.

If the upshift line α shown in FIG. 9 is not crossed, it is determined that the upshift is not performed, the subsequent processing is temporarily stopped, and the control routine is exited. on the other hand,
If it crosses the upshift line α, the ECT ECU 62 determines that an upshift has been performed, outputs an ON permission signal to the engine ECU 80 at T1 shown in FIG. 8, and proceeds to step 103. In step 103, it is determined whether or not gear change is in progress. That is, if the shift start condition is satisfied and the shift end condition is not satisfied, it is determined that the shift is in progress. If the shift start condition is not satisfied or the shift end condition is satisfied, it is determined that the shift is not in progress.

In step 103 of this embodiment, the shift start condition and the shift end condition are as follows. The shift start condition is No * ilow-A ≧ Nt.

That is, if the value obtained by subtracting the determination constant A from the product of the output shaft rotational speed No and the pre-shift gear ratio ilow is greater than or equal to the input shaft rotational speed Nt, the shift start condition is satisfied. The shift end condition is No * ihigh ≧ Nt-B.

That is, if the product of the output shaft speed No and the post-shift gear ratio ihigh is greater than or equal to the value obtained by subtracting the determination constant B from the input shaft speed Nt, the shift ending condition is satisfied. In addition,
Each gear ratio is stored in advance in the ROM of the ECT ECU 62, and is selectively read in this step 103 as a pre-shift gear ratio and a post-shift gear ratio based on the map used when it is determined to be an upshift in step 102. .

If it is determined in step 103 that the gear shift start condition is satisfied and the gear shift end condition is not satisfied, that is, if the gear shift is in progress, then in step 104 E
The CTECU 62 outputs an execution signal that is turned on to the engine ECU 80 at time T2 shown in FIG. Based on this execution signal, the engine ECU 80 obtains the target valve timing advance value α based on the map of engine speed NE and torque shown in FIG. The execution signal is when the shift end condition is satisfied (at T3 shown in FIG. 8).
Is turned off at.

Explaining the map here, the engine speed after the shift up of the map is the throttle opening T
A test value after the shift obtained by previously performing the shift up is used in a state where A is a constant value and the engine speed NE before the shift is a predetermined value. Then, when the throttle opening TA is a constant value and the engine speed after shifting up is a predetermined value, the valve timing advance value θVTA corresponding to the cam phase for obtaining a suitable torque characteristic is set to each throttle opening TA. It is predetermined for each of them.

Then, the target valve timing advance value α corresponding to the target cam phase in step 104 of this embodiment.
The method for obtaining is as follows. That is, since the engine speed NE before shifting at that time is known, the engine speed NE after shifting is also obtained from the map. In the post-shift engine speed NE, there are a plurality of valve timing advance values θVTA corresponding to each throttle opening TA, and the maximum target valve timing advance value θVTA is the target valve timing after the shift. The engine ECU 80 selects the advance value α.

Based on the target valve timing advance value α, the engine ECU 80 sets the opening degree of the electromagnetic switching valve 47 so that the actual cam movement speed can reach the target cam angle after the shift at the end of the shift. Drive control to a constant value,
The drive of the VVT 25 is controlled. Therefore, the opening / closing timing of the intake valve 8 is changed to the most advanced angle value, so that during the gear shift, the valve overlap is controlled by the most advanced angle value in the engine speed after the gear shift is completed.

If it is determined in step 103 that the gear change is not in progress, the engine ECU 80 determines in step 105 the valve timing advance value θVTA corresponding to the current operating condition such as the throttle opening TA and the engine speed NE. Calculate based on the input value. The calculation of the valve timing advance value θVTA in this case is performed with reference to an advance value map (not shown) that is determined according to the throttle opening TA and the engine speed NE. Then, based on the calculated valve timing advance value θVTA corresponding to the cam target value, the engine ECU
Reference numeral 80 controls the drive of the electromagnetic switching valve 47, and controls the drive of the VVT 25.

Note that the ECT ECU 62 turns off the shift permission signal after t time has elapsed from when the execution signal was turned off (at T3) as shown in FIG. As described above, in the present embodiment, the VVT 25 is controlled with the largest advance value among the advance values in the engine speed after the completion of the shift during the shift. That is, it means that a target greater than or equal to the optimum target cam phase after the actual shifting is set and controlled. Therefore,
Even when the actual cam phase has not reached the optimum target cam phase at the end of the gear shift, as shown in the actual cam phase of FIG. 8, the response is advanced by the amount corresponding to the effect. Incidentally, in the conventional case, when control is performed by the target cam phase shown by the chain double-dashed line in FIG. 8 during gear shifting, the actual cam phase of the prior art becomes as shown by the dotted line due to operation delay.

Therefore, as shown in FIG. 8, the output shaft torque of the automatic transmission 61 after the gear shift is improved more than the output shaft torque of the prior art, and the acceleration performance after the gear shift can be improved. .

On the other hand, when the actual cam phase advances beyond the optimum target cam phase at the end of gear shift, overshoot occurs. However, in the VVT 25 of the type in which both sides of the ring gear 42 are hydraulically driven, the responsiveness on the “advance side → retard side” is more than the responsiveness on the “retard side → advance side” due to the reaction force of the cam drive. Since it is better, it is possible to immediately return to the optimum cam phase when the control shifts to the normal control even in the case of overshoot.

Therefore, in this embodiment, the configuration for controlling the VVT 25 during the shift is different from the conventional one, and can be realized by a simple configuration, and the control itself can be a simple method.

The present invention is not limited to the above-mentioned embodiment, and can be arbitrarily modified without departing from the spirit of the present invention. (1) In the above-described embodiment, it is determined whether or not gear shifting is in progress. Output shaft rotation speed N0, input shaft rotation speed Nt, gear ratio before shift
Although the determination is made by calculating from w, the gear ratio ihigh after shifting, etc., the ignition retard execution command signal output from the engine ECU 80 when performing the known torque-down control during shifting (ignition retard control) instead May be determined to be the shift start, and similarly the command end of the execution command signal (falling of the execution command signal) may be determined to be the shift end.

(2) In addition, it is determined whether or not the gear change is in progress, it is determined that the gear change is started after t1 from the time T1 when the gear change is determined, and it is determined that the gear change is completed after t2 (t1 <t2) from the time T1. It may be determined that the gear is being changed.

(3) Although the VVT 23 that makes only the opening and closing timing of the intake valve 9 variable is provided, the VVT that makes only the opening and closing timing of the exhaust valve 10 variable and the opening and closing timings of both the intake valve 9 and the exhaust valve 10 are set. It is also possible to provide variable VVTs.

(4) In the above embodiment, the gasoline engine 1 is embodied, but it may be embodied as a diesel engine.

[0065]

As described above in detail, according to the first aspect of the present invention, when the valve timing of the variable valve timing mechanism is continuously controlled based on the engine speed of the internal combustion engine and the intake air amount, the gear shift is performed. The followability of the variable valve timing mechanism in the inside can be improved to prevent deterioration of acceleration performance due to switching delay of the variable valve timing mechanism.

Further, according to the second aspect of the invention, since it is not necessary to enhance the responsiveness of the control switching valve, there is an excellent effect that the cost and durability of the control valve can be improved.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram illustrating a basic conceptual configuration of the present invention.

FIG. 2 is a schematic configuration diagram illustrating a gasoline engine in one embodiment embodying the present invention.

FIG. 3 is a sectional view showing the structure of the VVT in the same manner.

FIG. 4 is a block diagram showing an electrical configuration of the engine ECU.

FIG. 5 is a characteristic diagram of engine speed and torque.

6 (a) and 6 (b) are explanatory views showing valve overlap, respectively.

FIG. 7 is a flowchart similarly illustrating a “VVT control routine”.

FIG. 8 is a time chart of an engine speed, an output shaft torque, a permission signal, an execution signal, a cam phase, etc. at the time of shifting.

FIG. 9 is a map used during gear shifting in which the relationship between vehicle speed and throttle opening is predetermined.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine as an internal combustion engine, 4 ... Combustion chamber, 6 ... Intake passage, 7 ... Exhaust passage, 8 ... Intake valve, 9 ... Exhaust valve, 25 ... VVT, 14 ... Throttle sensor, 14a ...
Full-closed switch, 30 ... Rotation speed sensor, 47 ... Electromagnetic switching valve as control valve, 62 ... ECT ECU constituting driving gear shift status determining means, 71 ... Intake air temperature sensor, 72 ... Throttle sensor, 73 ... Intake pressure sensor, 75 … Water temperature sensor, 7
6 ... Revolution sensor, 78 ... Vehicle speed sensor (72, 73, 7
6 constitutes an operating state detection means), 79 ...
Input speed sensor, 80 ... Engine ECU constituting valve timing determination means and drive control means.

Claims (2)

[Claims] 1. A variable valve timing mechanism, which is torsionally driven to continuously change the opening / closing timing of at least one of an intake valve and an exhaust valve, and an operating state detecting means for detecting an operating state of the internal combustion engine, Valve timing determination means for determining a valve timing target value based on the detection result of the operating state detection means; drive control means for driving and controlling the variable valve timing mechanism to control the opening / closing timing based on the valve timing target value; A driving speed change situation determining means for determining whether or not a gear shift should be performed based on the detection result of the driving state detecting means, wherein the drive control means is based on the determination result of the driving speed change situation determining means During this period, the control to the target value according to the driving condition is stopped and the driving condition is Lube timing mechanism valve timing control apparatus for an internal combustion engine and performing control as a target value the maximum cam phase target value in the direction opposite to the direction of movement by the cam torque. 2. The variable valve timing mechanism is a hydraulic drive type, and the drive control means is provided in a hydraulic system of the variable valve timing mechanism from the start time to the end of the shift, and the control valve opening degree controls the control hydraulic pressure. 2. The valve timing control device for an internal combustion engine according to claim 1, wherein the valve is controlled to a constant value.