JPH04321748A - Variable valve timing control apparatus - Google Patents

Abstract

PURPOSE:To select a state of small intake resistance and increase the fuel consumption rate to make it easier to control the speed of the vehicle, by fixing the throttle opening to a fully open state by a variable valve outputting means and controlling the operating angle of a variable valve so as to cause it to conform with a required acceleration by variable valve timing control or throttle opening control. CONSTITUTION:A target acceleration is calculated (59) from detection output of accelerator opening 57 and vehicle speed 52. A maximum engine torque at the time when the throttle is fully open is calculated from the number of engine revolutions 61. The acceleration of the vehicle is calculated (53) from the maximum engine torque. This acceleration 53 is compared with the target acceleration 59. When the target acceleration 59 is larger, the throttle opening 63 is made fully open and the operating angle of a variable valve 64 is controlled. Further, when the target acceleration 59 is smaller, the operating angle of the variable valve 64 is set to a maximum phase angle and the throttle opening 63 is controlled.

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 that allows the operating timing of intake and exhaust valves to be changed by variable valve timing control during engine operation.

0002

[Prior Art] This type of variable valve timing control device includes a housing with teeth formed inside, and teeth formed on the outer periphery of the housing via a ring gear in which at least one of the teeth formed on the inner and outer periphery is a helical tooth. Mounted on the camshaft, the engine's lubricating oil pressure acts as a control oil pressure in the axial direction of the ring gear, and the housing, which is rotationally driven by moving the ring gear, is rotated relative to the camshaft to open and close the valve. It is designed to change the operating timing.

This type of technology is disclosed in US Pat. No. 4,231,333.
The basic configuration is shown in No. 0. Also, JP-A-61-
The technology disclosed in Japanese Patent No. 268810 involves applying control hydraulic pressure to the housing driven by the engine in the axial direction of the ring gear to move the ring gear, causing it to rotate relative to the camshaft. The opening/closing timing of the driven intake or exhaust valve is made variable, and at this time, it acts to prevent control oil from leaking to the outer periphery of the housing, and also prevents the generation of drive noise due to the flexible belt. A technique for rotationally driving the housing without any problems has been disclosed.

0004

[Problem to be solved by the invention] The above-mentioned Japanese Patent Application Laid-Open No. 61-26
In the technology published in 8810, a control hydraulic pressure is applied to a housing driven by an engine in the axial direction of a ring gear to move the ring gear.
The camshaft is rotated relative to the camshaft, and the opening/closing timing of the intake or exhaust valves driven by the camshaft is varied, so that the engine and the opening/closing timing of the intake or exhaust valves are made to correspond to each other.

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

SUMMARY OF THE INVENTION An object of the present invention is to provide a variable valve timing control device that improves fuel efficiency without being affected by variable valve timing and without reducing accelerator feeling.

[0007]

[Means for Solving the Problems] A variable valve timing control device according to the present invention calculates a target acceleration from an accelerator opening degree and a vehicle speed detection output, calculates a maximum engine torque at a fully open throttle from an engine rotational speed, The acceleration of the vehicle is calculated from the maximum engine torque, the target acceleration and the acceleration are compared, and when the target acceleration is large, the throttle opening is fully opened and the operating angle of the variable valve is controlled. Furthermore, when the target acceleration is small, the operating angle of the variable valve is set to the maximum phase angle to control the throttle opening.

[0008]

[Operation] In this invention, the target acceleration calculation means calculates the target acceleration from the accelerator opening degree and the vehicle speed detection output, and the variable valve timing control area setting means calculates the maximum engine torque at full throttle from the engine rotation speed. is calculated, and the acceleration of the vehicle is calculated from the maximum engine torque. Comparing means compares the target acceleration of the target acceleration calculation means and 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 calculation means, The variable valve output means fixes the throttle opening at full open and controls the operating 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 region setting means, the variable throttle output means fixes the operating angle of the variable valve to the maximum phase angle and controls the throttle opening. . By fixing the throttle opening at full open and controlling the operating angle of the variable valve, the system selects a state with low intake resistance and improves fuel efficiency.

[0009]

[Embodiments] Hereinafter, embodiments of the present invention will be explained with reference to 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.

In FIG. 1, the inside of the engine 1 is omitted, but the valves that are opened and closed by the camshaft 2,
The timing of engine supply and exhaust is determined. The crankshaft 3 of the engine 1 serves as an output shaft, and also transmits rotation to the camshaft 1 via a variable valve timing (hereinafter simply referred to as "VVT") device 10 for opening and closing the valves. are doing. An oil pan section 6 containing oil is formed in the lower part of the engine 1.

The VVT device 10 that performs VVT control is configured as follows.

A ring-shaped piston means 13 having helical splines formed on the inner and outer circumferences is engaged between the timing pulley 11 having helical splines formed on the inner circumference and the transmission member 12 having helical splines formed on the outer circumference. It matches. Further, a timing belt 20 is placed over 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 onto the camshaft 2 by a bolt 14,
They are designed not to rotate relative to each other.

Further, the piston means 13 has two parts in its axial direction.
By dividing it into parts and inserting a spring 16 between them, a so-called scissor gear is created. This results in
When the rotational torque is transmitted from the timing pulley 11 to the piston means 13 and the transmission member 12, meshing noise due to backlash or the like occurring between each helical spline is reduced. and the illustrated right-hand space 19 of the piston means 13.
A spring 15 is disposed at and urges the piston means 13 to an initial position to the left as shown. The pressure receiving plate 17 disposed on the right side of the piston means 13 in the drawing moves together with the piston means 13, and the hydraulic line 1
The piston means 13 is moved in the left-right direction as shown in the figure in response to the oil pressure at 8.

[0015] The camshaft 2 is provided with protrusions 2a at positions equally divided at 60 degrees with respect to a cut surface cut perpendicularly to the length direction of the camshaft 2. A camshaft rotation detector 4 consisting of a magnetic sensor is disposed at a position facing the projection 2a. Similarly, protrusions 3a are formed on the crankshaft 3 at positions equally divided by 120 degrees with respect to a cut surface cut perpendicularly to the length direction thereof. A crankshaft rotation detector 5 consisting of a magnetic sensor is disposed at a position facing the projection 3a. Output of the camshaft rotation detector 4 and crankshaft rotation detector 5
The output of the control circuit 30 consisting of a microcomputer
is being input.

Oil to be used as lubricating oil for various parts of the engine is supplied from the oil pan section 6 containing oil in the lower part of the engine 1 to an engine oil pump 31 driven by the engine 1.
The water is pumped through the filter 32 and supplied through the filter 32. The relief valve 33 maintains the oil pressure pumped by the engine oil pump 31 at a constant oil pressure and returns excess oil pressure to the oil pan section 6 again. Further, a valve pressure pump 34 is connected on the same axis as the engine oil pump 31, and supplies oil to be used as lubricating oil for each part of the engine to the hydraulic line 18 via the filter 32 via the pressure control valve 36. are doing. The relief valve 35 is the valve supply pressure pump 34
The oil pressure pumped in is kept as a constant oil pressure, and the excess oil pressure is returned to the oil pan section 6 again. Further, the hydraulic pressure of the hydraulic line 18 is returned to the oil pan section 6 via the exhaust pressure control valve 37. The opening/closing control of the supply pressure control valve 36 and exhaust pressure control valve 37 is performed by duty ratio control of the control circuit 30.

Further, a vehicle speed signal, an accelerator opening signal, and an engine rotational speed signal are input to the control circuit 30, and a throttle opening control signal is output from the control circuit 30.

Therefore, the engine oil pump 3
The hydraulic pressure pumped in step 1 is further pressurized by a valve supply pressure pump 34, and is supplied to the hydraulic line 18 via a supply pressure control valve 36 whose duty ratio is controlled. This oil pressure causes the timing pulley 1, which has a helical spline on its inner circumference, to
1 and a transmission member 1 with a helical spline formed on the outer periphery.
The timing of the output of the camshaft rotation detector 4 which detects the protrusion 2a provided on the camshaft 2 and the output of the crankshaft rotation detector 5 which detects the protrusion 3a of the crankshaft 3 due to the engagement between the two is advanced or delayed based on the output of the crankshaft rotation detector 5 that detects the protrusion 3a of the crankshaft 3,
As a result, the opening/closing timing of the intake/exhaust valves of the engine 1 is advanced or delayed, and the ignition and intake/exhaust timings are obtained in accordance with the load of the engine 1.

The variable valve timing control device of this embodiment configured as described above is controlled as follows.

Since FIGS. 2 and 3 show the normal accelerator control program of the variable valve timing control system of this embodiment, this routine is called while the engine control main program (not shown) is being executed.

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

In step S6, the target acceleration obtained by adding target acceleration 2 to target acceleration 1 calculated in step S3 and step S5 is compared with the maximum acceleration possible with VVT control when the throttle is fully open, and the target acceleration is determined. When the acceleration is smaller than the maximum acceleration that is possible with VVT control when the throttle is fully open, the throttle opening is fully opened in step S7, and in step S8, the target acceleration is first multiplied by the vehicle weight to obtain the target engine torque, and this target engine torque is obtained. The VVT control operating angle when the throttle is fully open is calculated from the engine torque and engine speed. For this calculation, the VVT control operating angle is selected from the engine speed and engine torque of this embodiment shown in FIG. Further, in step S9, the actual acceleration that actually occurs is subtracted from the target acceleration and multiplied by a constant to calculate the VVT control operating angle difference when performing feedback control. Then, in step S10, the sum of the difference between the VVT control operating angle when the throttle is fully opened and the VVT control operating angle when performing feedback control is set as the output of the target VVT operating angle control.

[0023] In step S6, the V when the throttle is fully open is
When the maximum acceleration possible with the VT control is smaller than the target acceleration, the VVT control operating angle is set to the maximum phase angle in step S11, and in step S12, the target acceleration is first multiplied by the vehicle weight to obtain the target engine torque, From this target engine torque and engine rotational speed, the throttle opening degree with the VVT control operating angle as the maximum phase angle is calculated. For this calculation, the throttle opening degree is selected from the engine speed and engine torque of this embodiment shown in FIG. Also, step S1
In step 3, the actual acceleration that actually occurs is subtracted from the target acceleration and multiplied by a constant to calculate the throttle opening difference when performing feedback control. And 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 set 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 explained as follows.

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

In FIG. 9, an output shaft of an engine 50 is outputted via an automatic transmission 51. As shown in FIG. A vehicle speed detection means 52 detects the vehicle speed from the output of the automatic transmission 51, and is further connected to an acceleration detection means 53 that calculates acceleration based on the differentiation of the vehicle speed, from which the acceleration is detected.

Accelerator operation means 56 such as an accelerator pedal
The output of
The output of the accelerator opening detection means 57 is led to the accelerator opening speed calculation means 58, where the change in the accelerator opening is determined as the accelerator opening speed, and the output of the accelerator opening detection means 57 and the accelerator opening speed are calculated. The output of the calculation means 58 is guided to the target acceleration calculation means 59. The target acceleration calculating means 59 inputs the vehicle speed from the vehicle speed detecting means 52 to obtain target acceleration 1 and target acceleration 2 shown in FIGS. 4 and 5. This function corresponds to steps S1 to S3. Further, the VVT control area setting means 60 inputs target acceleration 1 and target acceleration 2 from the target acceleration calculation means 59, inputs a predetermined gear stage from the shift control means 55 that controls the automatic transmission 51, and, The rotation speed of the engine 50 is detected from the ignition circuit unit, that is, the igniter 14
is connected to the engine rotation speed detection means 61 to which the ignition signal is input and the engine rotation speed is detected from there.
is input, and the maximum engine torque at full throttle is calculated from the engine speed. This function corresponds to step S4 and step S5.

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

Further, the target acceleration calculation means 59 and V
The output of the VT control region setting means 60 is compared by the VVT operating angle calculation means 62, and the output of the VVT control region setting means 60 is compared.
When the output of the target acceleration calculation means 59 is smaller than VV
Control is performed by the VVT control means 64 using the T control region setting means 60. This function is performed in step S6 and step S11.
This corresponds to steps S14 to S14.

As described above, the variable valve timing control device of the present embodiment includes a target acceleration calculation means consisting of steps S1 to S3 for calculating a target acceleration from the accelerator opening degree and the vehicle speed detection output, and a target acceleration calculation means for calculating the target acceleration from the engine rotation speed. Step S4 of calculating the maximum engine torque at the time and calculating the acceleration of the vehicle from the maximum engine torque.
and a variable valve timing control region setting means comprising step S5, a comparison means comprising step S6 for comparing the target acceleration of the target acceleration calculation means and the acceleration of the variable valve timing control region setting means, and the target acceleration calculation means. variable valve output means comprising steps S7 to S10 for fully opening the throttle opening and controlling the operating angle of the variable valve when the acceleration of the variable valve timing control region setting means is smaller than the target acceleration; When the target acceleration of the target acceleration calculation means is smaller than the acceleration of the control area setting means, the operating angle of the variable valve is set to the maximum phase angle, and the throttle opening degree is controlled from step S11 to step S1.
4 and a variable throttle output means.

Therefore, the driver's target acceleration, that is, the required acceleration, is determined from the accelerator opening degree, and the maximum engine torque when the throttle is fully opened by VVT control is calculated based on the engine rotational speed, and the required acceleration is determined from the maximum engine torque. When it is low, the necessary torque can be obtained by VVT control with the throttle fully open, so it is possible to lower intake resistance and improve fuel efficiency. Furthermore, when the required acceleration is lower than the maximum engine torque when the throttle is fully opened under VVT control based on the engine speed, the operating angle of the variable valve under VVT control is set to the maximum phase angle to control the throttle opening. Therefore, regardless of the magnitude relationship between the maximum engine torque when the throttle is fully opened under VVT control based on the engine speed and the driver's requested acceleration at that time, it is possible to match it to a predetermined requested acceleration using VVT control or throttle opening control. As a result, the accelerator feeling does not change depending on driving conditions, resulting in a good accelerator feeling.

By the way, in the above embodiment, the target acceleration and the like are selected from the memory map, but when the present invention is implemented, they can be calculated each time. but,
If a memory map is used as in this embodiment, the processing speed can be increased.

[0033]

As described above, the variable valve timing control device of the present invention obtains the target acceleration from the accelerator opening and vehicle speed using the target acceleration calculation means, and calculates the throttle from the engine speed using the variable valve timing control region setting means. The maximum engine torque at full throttle is obtained, and 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 the variable valve timing is determined based on the target acceleration of the target acceleration calculation means. When the acceleration of the control region setting means is small, the variable valve output means fixes the throttle opening at full open and controls the operating 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 region setting means, the variable throttle output means fixes the operating angle of the variable valve to the maximum phase angle and controls the throttle opening. It is something.

Therefore, since the variable valve output means fixes the throttle opening at full open and controls the operating angle of the variable valve, it is possible to select a state with small intake resistance and improve fuel efficiency.

Furthermore, regardless of the comparison result between the target acceleration of the target acceleration calculation means and the acceleration of the variable valve timing control area setting means, the required acceleration can be matched by variable valve timing control or throttle opening control. This prevents the accelerator feeling from changing, such as changes in the amount of depression, while driving. Therefore, vehicle speed control becomes easier.

[Brief explanation of 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 a variable valve timing control device according to an embodiment of the present invention.

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

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

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

FIG. 6 is an explanatory diagram of a memory map of the maximum engine torque that is possible with VVT control used in the variable valve timing control device of one embodiment of the present invention.

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

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

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

[Explanation of symbols]

1,50 Engine 10 VVT (variable valve timing)
Device 51 Automatic transmission 52 Vehicle speed detection means 55 Shift control means 57 Accelerator opening detection means 61
Engine rotation speed detection means 30
control circuit

Claims (1)

[Claims] 1. Target acceleration calculating means for calculating a target acceleration from an accelerator opening degree and a vehicle speed detection output, calculating a maximum engine torque at a fully open throttle from an engine rotational speed, and calculating vehicle acceleration from the maximum engine torque. variable valve timing control region setting means; comparison means for comparing the target acceleration of the target acceleration calculation means and the acceleration of the variable valve timing control region setting means;
When the acceleration of the variable valve timing control region setting means is smaller than the target acceleration of the target acceleration calculation means,
When the throttle opening is fully open and the target acceleration of the target acceleration calculation means is smaller than the acceleration of the variable valve output means for controlling the operating angle of the variable valve and the variable valve timing control area setting means, the operating angle of the variable valve is 1. A variable valve timing control device, comprising variable throttle output means for controlling a throttle opening at a maximum phase angle.