JP3020232B2 - Variable valve timing control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve timing control device capable of changing the operation timing of a supply / exhaust valve during operation of an engine by variable valve timing control.

[0002]

2. Description of the Related Art As a variable valve timing control device of this kind, a housing having teeth formed therein is provided with teeth formed on the outer periphery thereof through a ring gear in which at least one of the teeth formed on the inner and outer periphery is a helical tooth. Attached to the camshaft, the lubricating oil pressure of the engine acts as control oil pressure in the axial direction of the ring gear, and the housing that is rotationally driven by moving the ring gear is rotated relatively to the camshaft to open and close the valve. The operation timing is changed.

[0003] This type of technology is disclosed in US Patent No. 423133.
No. 0 shows the basic configuration. In addition, Japanese Unexamined Patent Publication No.
In the technique disclosed in Japanese Patent Publication No. 268810, a housing driven by an engine is controlled relative to a camshaft by applying a control oil pressure in the axial direction of a ring gear to move the ring gear. The opening / closing operation timing of the driven intake or exhaust valve is made variable, and at this time, it acts to prevent the control oil from leaking to the outer periphery of the housing, and generates driving noise due to the flexible belt. There is disclosed a technique for rotating the housing without rotating the housing.

[0004]

SUMMARY OF THE INVENTION The above-mentioned JP-A-61-26 is disclosed.
In the technique disclosed in Japanese Patent No. 8810, a housing driven by an engine is controlled by applying control oil pressure in the axial direction of a ring gear to move the ring gear.
The opening / closing operation timing of the intake or exhaust valve driven by the camshaft is changed by rotating the camshaft relative to the camshaft, and the engine is associated with the opening / closing operation timing of the intake or exhaust valve.

However, when the load is low, the intake valve is retarded or advanced, and the driver opens the throttle valve by an amount corresponding to the decrease in engine torque, thereby reducing intake resistance and improving fuel efficiency. The accelerator feeling was not good.

Accordingly, an object of the present invention is to provide a variable valve timing control device that improves fuel economy without being affected by the variable valve timing and without deteriorating the accelerator feeling.

[0007]

A variable valve timing control device according to the present invention calculates a target acceleration from an accelerator opening and a vehicle speed detection output, and calculates a maximum engine torque when the throttle is fully opened from an engine speed. The acceleration of the vehicle is calculated from the maximum engine torque, and the target acceleration is compared with the acceleration. When the target acceleration is large, the throttle opening is fully opened and the operation angle of the variable valve is controlled. When the target acceleration is small, the operation angle of the variable valve is set to the maximum phase angle, and the throttle opening is controlled.

[0008]

According to the present invention, the target acceleration is calculated from the accelerator opening and the vehicle speed detection output by the target acceleration calculating means, and the maximum engine torque when the throttle is fully opened is calculated from the engine speed by the variable valve timing control area setting means. Is calculated, and the acceleration of the vehicle is calculated from the maximum engine torque. The comparing means compares the target acceleration of the target acceleration calculating means with the acceleration of the variable valve timing control area setting means, and when the acceleration of the variable valve timing control area setting means is smaller than the target acceleration of the target acceleration calculating means, The variable valve output means fixes the throttle opening to full open and controls the operation angle of the variable valve. Conversely, when the target acceleration of the target acceleration calculation means is smaller than the acceleration of the variable valve timing control area setting means, the operation angle of the variable valve is fixed to the maximum phase angle by the variable throttle output means, and the throttle opening is controlled. . By fixing the throttle opening to full open and controlling the operation angle of the variable valve, a state in which the intake resistance is small is selected to improve fuel efficiency.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall control configuration diagram of a variable valve timing control device according to one embodiment of the present invention.

In FIG. 1, although the inside of the engine 1 is omitted, a valve opened and closed by a cam shaft 2
The timing of supply and exhaust of the engine is determined. The crankshaft 3 of the engine 1 serves as an output shaft, and transmits rotation to the camshaft 1 via a variable valve timing (hereinafter simply referred to as “VVT”) device 10 for opening and closing the valve. are doing. An oil pan 6 containing oil therein is formed at a lower portion of the engine 1.

The VVT device 10 for performing VVT control is configured as follows.

Between a timing pulley 11 having a helical spline on the inner periphery and a transmission member 12 having a helical spline on the outer periphery, a ring-shaped piston means 13 having helical splines formed on the inner and outer periphery respectively is engaged. I agree. A timing belt 20 is hung on the outer peripheral surface of the timing pulley 11 and is driven by the crankshaft 3 of the engine 1. Here, the transmission member 12 is screwed to the camshaft 2 by a bolt 14,
They do not rotate relative to each other.

Further, the piston means 13 has two axial directions.
It is divided and a so-called scissors gear is achieved by inserting a spring 16 between them. Thus, when the rotational torque is transmitted from the timing pulley 11 to the piston means 13 and the transmission member 12, the meshing noise due to backlash or the like generated between the helical splines is reduced. A spring 15 is provided in a right space 19 of the piston means 13 as shown in FIG.
To the initial position of the leftward position shown in the figure. Then, the pressure receiving plate 17 arranged on the right side of the piston means 13 in the figure moves together with the piston means 13, and moves the piston means 13 in the left and right directions in the figure according to the oil pressure of the hydraulic line 18.

The camshaft 2 is provided with a projection 2a at a position equally divided by 60 degrees with respect to a cutting plane cut vertically in the longitudinal direction. A camshaft rotation detector 4 composed of a magnetic sensor is disposed at a position facing the protrusion 2a. Similarly, the crankshaft 3 is formed with a projection 3a at a position equally divided by 120 degrees with respect to a cut surface cut vertically in the longitudinal direction. A crankshaft rotation detector 5 composed of a magnetic sensor is provided at a position facing the projection 3a. Output of the camshaft rotation detector 4 and crankshaft rotation detector 5
Is output from a control circuit 30 comprising a microcomputer.
Is being entered.

The oil used as the lubricating oil for the various parts of the engine from the oil pan 6 containing the oil under the engine 1 is supplied to the engine oil pump 31 driven by the engine 1.
And is supplied through a filter 32. The relief valve 33 keeps the oil pressure drawn by the engine oil pump 31 constant, and returns the surplus oil pressure to the oil pan section 6 again. Further, a valve supply pressure pump 34 is connected on the same axis as the engine oil pump 31, and supplies oil used as a lubricating oil for each part of the engine via the filter 32 to the hydraulic line 18 via a supply pressure control valve 36. are doing. The relief valve 35 is a valve pressure pump 34.
The hydraulic pressure drawn in step S1 is made constant, and the excess hydraulic pressure is returned to the oil pan section 6 again. In addition, the oil pressure in the oil pressure line 18 is returned to the oil pan section 6 via the exhaust pressure control valve 37. The opening and closing control of the supply pressure control valve 36 and the exhaust pressure control valve 37 is performed by the duty ratio control of the control circuit 30.

The control circuit 30 receives a vehicle speed signal, an accelerator opening signal, and an engine speed signal. The control circuit 30 outputs a throttle opening control signal.

Therefore, the engine oil pump 3
The hydraulic pressure drawn in step 1 is further pressurized by a valve pressure pump 34 and supplied to the hydraulic line 18 via a pressure control valve 36 whose duty ratio is controlled. By this hydraulic pressure, camshaft rotation for detecting a projection 2a provided on the camshaft 2 by meshing between a timing pulley 11 having a helical spline on the inner periphery and a transmission member 12 having a helical spline on the outer periphery. The output of the detector 4;
The timing of the output of the crankshaft rotation detector 5 for detecting the projection 3a of the crankshaft 3 is advanced or delayed with reference to the output of the crankshaft rotation detector 5 for detecting the projection 3a of the crankshaft 3, resulting in In addition, the opening / closing timing of the supply / exhaust valve of the engine 1 is advanced or delayed, and the ignition and supply / exhaust timing according to the load of the engine 1 can be obtained.

The variable valve timing control device according to the present embodiment having the above-described configuration is controlled as follows.

FIGS. 2 and 3 show a normal accelerator control program of the variable valve timing control device according to the present embodiment. Therefore, this routine is called during execution of an engine control main program (not shown).

First, at step S1, a target acceleration 1 is calculated from the vehicle speed and the accelerator opening. In this calculation, as shown in the memory map of the target acceleration 1 of the present embodiment in FIG.
A value calculated as to how much acceleration can be obtained at a specific vehicle speed is stored in a memory map, and a target acceleration 1 is selected from the vehicle speed and the accelerator opening. In step S2, the target acceleration 2 is calculated from the accelerator opening speed obtained from the vehicle speed and the accelerator opening changing speed. In this calculation, as shown in the memory map of the target acceleration 2 of the present embodiment in FIG. 5, the target acceleration 2 is selected from the vehicle speed and the accelerator opening speed. In step S3, the target acceleration 2 is added to the target acceleration 1 to calculate a target acceleration that is a required acceleration. In step S4, the maximum engine torque that can be achieved by the VVT control when the throttle is fully opened is calculated from the engine speed. In this calculation, as shown in the memory map of the maximum engine torque enabled by the VVT control of the present embodiment in FIG.
Select the maximum engine torque that is possible with T control. In step S5, the maximum engine torque enabled by the VVT control when the throttle is fully opened obtained in step S4 is reduced by the gear ratio of the automatic transmission at that time, and the maximum acceleration enabled by the VVT control when the throttle is fully opened is determined. .

In step S6, the target acceleration obtained by adding the target acceleration 2 to the target acceleration 1 calculated in steps S3 and S5 is compared with the maximum acceleration that can be achieved by the VVT control when the throttle is fully opened. When the acceleration is smaller than the maximum acceleration that can be achieved by the VVT control when the throttle is fully opened, the throttle opening is fully opened in step S7, and in step S8, first, the target acceleration is multiplied by the vehicle weight to obtain the target engine torque. A VVT control operation angle when the throttle is fully opened is calculated from the engine torque and the engine speed. For this calculation, the VVT control operating angle is selected from the engine speed and the engine torque of this embodiment in FIG. In step S9, the actual acceleration actually generated with respect to the target acceleration is subtracted, and a constant is multiplied by a constant to calculate a VVT control operating angle difference when performing feedback control. Then, in step S10, the sum of the VVT control operation angle when the throttle is fully opened and the VVT control operation angle difference at the time of performing the feedback control is used as the output of the target VVT operation angle control.

In step S6, the V when the throttle is fully opened is
When the maximum acceleration that can be achieved by the VT control is smaller than the target acceleration, the VVT control operation angle is set to the maximum phase angle in step S11. In step S12, first, the target acceleration is multiplied by the vehicle weight to obtain the target engine torque. From this target engine torque and engine speed, the throttle opening with the VVT control operating angle as the maximum phase angle is calculated. In this calculation, the throttle opening is selected from the engine speed and the engine torque of the present embodiment in FIG. Step S1
In step 3, the actual acceleration actually generated is subtracted from the target acceleration, and the resultant value is multiplied by a constant to calculate a throttle opening degree difference when performing feedback control. Then, step S1
In step 4, the sum of the throttle opening with the VVT control operating angle as the maximum phase angle and the throttle opening difference when performing feedback control is used as the output of the target throttle opening control.

The function of the control circuit 30 of the variable valve timing control device of the above embodiment will be described below.

FIG. 9 is a functional explanatory diagram of the control circuit 30 of the variable valve timing control device according to one embodiment of the present invention.

In FIG. 9, the output shaft of the engine 50 is output via an automatic transmission 51. The vehicle speed is detected by the vehicle speed detecting means 52 from the output of the automatic transmission 51. Further, an acceleration detecting means 53 for calculating an acceleration by differentiating the vehicle speed is connected, and the acceleration is detected therefrom.

Accelerator operation means 56 such as an accelerator pedal
Is output to accelerator opening detecting means 57 comprising a potentiometer or the like, where the accelerator opening is detected.
The output of the accelerator opening detecting means 57 is led to an accelerator opening speed calculating means 58, where a change in the accelerator opening is obtained and used as an accelerator opening speed. The output of the accelerator opening detecting means 57 and the accelerator opening speed are obtained. The output of the calculating means 58 is guided to the target acceleration calculating means 59. The target acceleration calculating means 59 receives the vehicle speed from the vehicle speed detecting means 52 and obtains the target acceleration 1 and the target acceleration 2 shown in FIGS. This function corresponds to steps S1 to S3. Further, the VVT control region setting means 60 inputs the target acceleration 1 and the target acceleration 2 from the target acceleration calculating means 59, and inputs a predetermined shift speed from the shift control means 55 for controlling the automatic transmission 51; The number of revolutions of the engine 50 is detected from the ignition circuit unit, that is, the igniter 1
And an engine speed detecting means 6 to which an ignition signal is input and from which an engine speed is detected.
1 is input, and the maximum engine torque when the throttle is fully opened is calculated from the engine speed. This function corresponds to steps S4 and S5.

The outputs of the target acceleration calculation means 59 and the VVT control area setting means 60 are compared by the throttle opening degree calculation means 54.
When the output of the T control area setting means 60 is small, the drive control of the throttle drive means 63 is performed. This function corresponds to steps S6 to S10.

The target acceleration calculating means 59 and V
The output of the VT control area setting means 60 is compared by the VVT operating angle calculation means 62 and the VVT control area setting means 60
When the output of the target acceleration calculating means 59 is smaller, VV
The VVT control means 64 controls the T control area setting means 60. This function is performed in steps S6 and S11.
To step S14.

As described above, the variable valve timing control apparatus according to the present embodiment includes the target acceleration calculating means including steps S1 to S3 for calculating the target acceleration from the accelerator opening and the vehicle speed detection output, and the throttle fully open from the engine speed. Calculating the maximum engine torque at the time and calculating the acceleration of the vehicle from the maximum engine torque in step S4.
And a variable valve timing control area setting means comprising: step S5; a comparing means comprising: step S6 for comparing a target acceleration of the target acceleration calculating means with an acceleration of the variable valve timing control area setting means; When the acceleration of the variable valve timing control area setting means is smaller than the target acceleration of the above, the throttle valve is fully opened and the variable valve output means comprising steps S7 to S10 for controlling the operation angle of the variable valve; When the target acceleration of the target acceleration calculation means is smaller than the acceleration of the control area setting means, the operation angle of the variable valve is set to the maximum phase angle and the throttle opening is controlled in steps S11 to S1.
And 4 variable throttle output means.

Therefore, the target acceleration of the driver, that is, the required acceleration, is determined from the accelerator opening, and the maximum engine torque when the throttle is fully opened by VVT control is calculated based on the engine speed.
Calculates the acceleration of the vehicle from
VVT control when the throttle opening is fully open
As a result, a necessary torque can be obtained, so that intake resistance can be reduced and fuel efficiency can be improved. When the required acceleration is lower than the maximum engine torque when the throttle is fully opened based on the VVT control based on the engine speed, the operation angle of the variable valve based on the VVT control is set to the maximum phase angle, and the throttle opening is controlled. Therefore, without asking the magnitude relationship between the maximum engine torque when the throttle is fully opened by the VVT control based on the engine speed and the required acceleration of the driver at that time, the VVT control or the throttle opening control associates the predetermined acceleration with the predetermined required acceleration. Therefore, the accelerator feeling does not change depending on the driving conditions, and as a result, the accelerator feeling is good.

In the above-described embodiment, the target acceleration and the like are selected from the memory map. However, when the present invention is implemented, it can be obtained by calculation each time. But,
If a memory map is used as in this embodiment, the processing speed can be increased.

[0033]

As described above, according to the variable valve timing control device of the present invention, the target acceleration is obtained from the accelerator opening and the vehicle speed by the target acceleration calculating means, and the throttle is calculated from the engine speed by the variable valve timing control area setting means. The maximum engine torque at the time of full opening is obtained, the comparison means compares the target acceleration of the target acceleration calculation means with the acceleration of the variable valve timing control area setting means, and calculates the variable valve timing from the target acceleration of the target acceleration calculation means. When the acceleration of the control area setting means is small, the throttle opening is fixed to the full opening by the variable valve output means, and the operation angle of the variable valve is controlled. Conversely, when the target acceleration of the target acceleration calculation means is smaller than the acceleration of the variable valve timing control area setting means, the operation angle of the variable valve is fixed to the maximum phase angle by the variable throttle output means, and the throttle opening is controlled. Things.

Accordingly, since the throttle opening is fixed to the full open state by the variable valve output means and the operating angle of the variable valve is controlled, a state in which the intake resistance is small can be selected to improve fuel efficiency.

Also, whatever the result of the comparison between the target acceleration of the target acceleration calculating means and the acceleration of the variable valve timing control area setting means, the required acceleration is made to correspond to the required acceleration by the variable valve timing control or the throttle opening control. Therefore, the accelerator feeling such as a change in the amount of stepping does not change during traveling. Therefore, vehicle speed control becomes easy.

[Brief description of the drawings]

FIG. 1 is an overall control configuration diagram of a variable valve timing control device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a main part of a normal accelerator control program of the variable valve timing control device according to one embodiment of the present invention.

FIG. 3 is a flowchart showing a part of a normal accelerator control program of the variable valve timing control device according to one embodiment of the present invention.

FIG. 4 is an explanatory diagram of a memory map of a target acceleration 1 used in the variable valve timing control device according to one embodiment of the present invention.

FIG. 5 is an explanatory diagram of a memory map of a target acceleration 2 used in the variable valve timing control device according to one embodiment of the present invention.

FIG. 6 is an explanatory diagram of a memory map of a maximum engine torque enabled by VVT control used in the variable valve timing control device according to one embodiment of the present invention.

FIG. 7 is an explanatory diagram of a memory map of a throttle opening used in the variable valve timing control device according to one embodiment of the present invention.

FIG. 8 is an explanatory diagram of a memory map of a VVT control operation angle used in the variable valve timing control device according to one embodiment of the present invention.

FIG. 9 is an explanatory diagram of functions of a control circuit of the variable valve timing control device according to one embodiment of the present invention.

[Explanation of symbols]

 1, 50 engine 10 VVT (variable valve timing) device 51 automatic transmission 52 vehicle speed detecting means 55 shift control means 57 accelerator opening degree detecting means 61 engine speed detecting means 30 control circuit

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toru Fujikawa Examiner, Aisin Seiki Co., Ltd. 2-1-1 Asahi-cho, Kariya-shi, Aichi Pref. Hiroshi Abe (56) References JP-A-63-219839 (JP, A) JP-A-62-282148 (JP, A) JP-A-63-309742 (JP, A) JP-A-61-65036 (JP, A) JP-A-61-268810 (JP, A) JP-A-2-301634 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 43/00 F02D 13/02 F02D 41/10

Claims (1)

(57) [Claims] 1. A target acceleration calculating means for calculating a target acceleration from an accelerator opening and a vehicle speed detection output, a maximum engine torque when the throttle is fully opened from an engine speed, and a vehicle acceleration from the maximum engine torque. Variable valve timing control area setting means, comparing means for comparing the target acceleration of the target acceleration calculation means with the acceleration of the variable valve timing control area setting means,
When the acceleration of the variable valve timing control area setting means is smaller than the target acceleration of the target acceleration calculating means,
When the throttle opening is fully opened, the variable valve output means for controlling the operation angle of the variable valve, and when the target acceleration of the target acceleration calculation means is smaller than the acceleration of the variable valve timing control area setting means, the operation angle of the variable valve is changed. A variable throttle output means for controlling a throttle opening degree with a maximum phase angle.