JP2001107777A - Intake amount control device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a speed reduction shock at the speed reduction operation time from a high car speed, prevent the increase of a catalyst temperature and reduce the return shock from a fuel cut without hurting the speed reduction feeling at the speed reduction operation time from a low car speed. SOLUTION: This device is provided with a bypass passage for detouring a throttle valve to the intake passage of an engine, a bypass air amount control valve for adjusting the bypass air amount of this bypass passage, a throttle sensor for detecting a throttle opening, a car speed sensor for detecting the car speed and a control means for increasing the intake amount of the engine by the initial value of the bypass air amount for speed reduction set by the throttle opening just before the entire closing at the speed reduction operation start time of the engine by the entire closing of the throttle valve and also for controlling the bypass air amount control valve so as to time-attenuating this initial value by the attenuation amount set according to the car speed during the speed reduction operation of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake air amount control device for an engine, and more particularly, to reducing a deceleration shock due to a throttle valve being fully closed during a deceleration operation of the engine from a high vehicle speed and preventing an increase in catalyst temperature. Further, the present invention relates to an intake air amount control device for an engine capable of reducing a return shock at the time of returning from a fuel cut without impairing a sense of deceleration of the vehicle during a deceleration operation of the engine from a low vehicle speed.

[0002]

2. Description of the Related Art In a vehicle engine, a bypass passage bypassing a throttle valve is provided in an intake passage, and a bypass air amount control valve for adjusting a bypass air amount in the bypass passage is provided. There is an apparatus provided with an intake air amount control device for controlling the intake air amount.

[0003] This intake air amount control device for an engine controls the bypass air amount control valve in accordance with the operating state of the engine, thereby adjusting the bypass air amount and controlling the intake air amount of the engine. Accordingly, the intake air amount control device controls the bypass air amount control valve so as to adjust the bypass air amount according to the difference between the engine speed and the target idle speed, for example, during idle operation of the engine (idle control). Accordingly, the intake air amount is controlled so that the engine speed becomes the target idle speed.

[0004] An example of such an intake air amount control device for an engine is disclosed in Japanese Patent No. 2541190. What is disclosed in this publication is to control an air control valve in a bypass passage so as to increase and correct an intake air amount according to a drive state of a transmission or an air conditioner compressor as an engine auxiliary during an engine deceleration operation,
After the engine speed becomes equal to or lower than a predetermined value, the correction value of the increase correction is attenuated in accordance with the driving state of the engine accessory, and the correction amount is attenuated according to the driving state of the accessory. Are prepared for multiple values.

[0005]

When the engine is decelerated by fully closing the throttle valve and the intake passage is closed by suddenly closing the throttle valve, the engine is decelerated by engine braking due to a sudden decrease in the amount of intake air. There is a problem that a shock is generated, and a high-temperature exhaust gas stays in the catalyst, thereby increasing the catalyst temperature and decreasing the purification function.

To solve such a problem, as shown in FIG. 8, during deceleration operation by fully closing the throttle valve, the intake air amount of the engine is increased by the initial value (dashpot amount) of the deceleration bypass air amount. There is an intake air amount control device that controls a bypass air amount control valve (dashpot control) to reduce a deceleration shock and avoid a rise in catalyst temperature.

In this intake air amount control device, the initial value of the deceleration bypass air amount which is increased during the deceleration operation of the engine is set by the throttle opening immediately before the fully closed state, and the initial value of the deceleration bypass air amount is decelerated. It is attenuated by the amount of attenuation per unit time so that it becomes zero during operation. This attenuation amount is set to a constant value.

However, in the conventional intake air amount control device, the engine speed, which is reduced by the deceleration operation of the engine due to the full closing of the throttle valve from a low vehicle speed, is reduced by the fuel cut return rotation for stopping the fuel cut performed during the deceleration operation. The damping amount is set so that the initial value of the deceleration bypass air amount becomes zero before the number reaches the number.

Therefore, in the conventional intake air amount control device, the initial value of the deceleration bypass air amount becomes zero during deceleration during the deceleration operation of the engine from a high vehicle speed, and the deceleration bypass air amount can be secured. As a result, there is a disadvantage that the deceleration shock is generated and a problem that the catalyst temperature is increased is caused.

On the other hand, if the deceleration bypass air amount is set to be secured during the deceleration operation of the engine from a high vehicle speed, as shown in FIG. 9, the deceleration operation is performed during the deceleration operation from a low vehicle speed. Even if the reduced engine speed reaches the fuel cut return rotation speed, the amount of bypass air for deceleration remains, causing the disadvantage of impairing the sense of deceleration of the vehicle. There is inconvenience to do.

[0011]

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned disadvantages, the present invention provides an intake passage of an engine mounted on a vehicle with a bypass passage bypassing a throttle valve. A throttle air sensor for detecting the throttle opening of the throttle valve, a vehicle speed sensor for detecting the vehicle speed of the vehicle, and a deceleration operation of the engine by fully closing the throttle valve. At the start, the intake air amount of the engine is increased by the initial value of the deceleration bypass air amount set by the throttle opening just before full closing, and the initial value is set according to the vehicle speed during the deceleration operation of the engine. Control means for controlling the bypass air amount control valve so as to attenuate time by the amount of attenuation per time is provided. That.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an engine intake amount control apparatus according to the present invention, the control means sets the engine intake amount at the start of deceleration operation of the engine by fully closing the throttle valve according to the throttle opening immediately before the fully closed state. The bypass air amount control valve is controlled so as to increase by an initial value of the bypass air amount for deceleration and to attenuate the initial value by the amount of attenuation per unit time set according to the vehicle speed during the deceleration operation of the engine. By this, the initial value of the deceleration bypass air amount set at the start of the deceleration operation of the engine can be attenuated according to the vehicle speed so that it becomes zero before returning to the fuel cut, and the vehicle speed during the deceleration operation is reduced. Accordingly, the deceleration bypass air amount can be secured in each case.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 7 show an embodiment of the present invention. In FIG. 7, 2 is an engine mounted on a vehicle (not shown), 4 is a cylinder block, 6 is a cylinder head, 8 is a head cover, 10 is a piston, 12 is a combustion chamber, 14 is an intake port, 16 is an exhaust port, and 18 is An intake valve, 20 is an exhaust valve, and 22 is a spark plug.

The engine 2 has an intake passage 34 communicating with the intake port 14 by sequentially connecting an air cleaner 24, an intake pipe 26, a throttle body 28, a surge tank 30, and an intake manifold 32 as an intake system. A throttle valve 36 is provided in an intake passage 34 of the throttle body 28.
Is provided.

The engine 2 is provided with an exhaust passage 44 which sequentially connects an exhaust manifold 38, an exhaust pipe 40, and a catalytic converter 42 as an exhaust system, and communicates with the exhaust port 16. A catalyst 46 is provided in the catalytic converter 42. The engine 2 includes an exhaust passage 44 and an intake passage 34.
And an EGR control valve 50 is provided in the EGR passage 48.

The engine 2 has a head cover 8 provided with a PC.
A V-valve 52 is attached and provided, and a first blow-by gas passage 54 that connects the inside of the head cover 8 and the intake passage 34 of the surge tank 30 through the PCV valve 52 is provided.
Intake passage 3 in head cover 8 and throttle body 28
4 is provided with a second blow-by gas passage 56 communicating with the second blow-by gas.

The engine 2 has a fuel injection valve 58 provided in the cylinder head 6 so as to be directed toward the combustion chamber 12. The fuel injection valve 58 is connected to the fuel tank 6 by the fuel supply passage 60.
2 has been contacted. A fuel pump 64 for supplying fuel to the fuel supply passage 60 is provided in the fuel tank 62. A fuel filter 66 is provided in the fuel supply passage 60.

In the middle of the fuel supply passage 60, a pressure regulator 68 for adjusting the fuel pressure is provided. The pressure regulator 68 is connected to the surge tank 30.
The pressure in the intake passage 34 is introduced as an adjustment pressure through the adjustment pressure passage 70, the fuel pressure is adjusted to a predetermined pressure, and excess fuel is returned to the fuel tank 62 through the fuel return passage 72.

In the fuel tank 62, an evaporative passage 74 is provided.
Communicates with one end of the The other end of the evaporation passage 74 is
It is connected to the canister 76. A two-way valve 78 is provided in the middle of the evaporation passage 74. One end of the purge passage 80 communicates with the canister 76. The other end of the purge passage 80 communicates with the intake passage 34 of the surge tank 30. In the middle of the purge passage 80, a purge control valve 82 for adjusting a purge amount is provided.

The engine 2 bypasses the throttle valve 36 and connects the intake passage 34 of the throttle body 28 and the intake passage 34 of the surge tank 30 to a bypass passage 84.
Is provided. In the middle of the bypass passage 84, a bypass air amount control valve 86 for adjusting the bypass air amount is provided.

The engine 2 is provided with an ignition coil 88 for causing the spark plug 22 to ignite, a crank angle sensor 90 for detecting the crank angle and the engine speed, and a water temperature sensor 9 for detecting the temperature of the cooling water of the engine 2.
2, an idle switch 96 which is turned on when the throttle valve 36 is fully closed (idle opening), and a throttle sensor 94 for detecting the throttle opening of the throttle valve 36 is provided.
, An intake air temperature sensor 98 for detecting the intake air temperature in the intake passage 34, an intake air amount sensor 100 for detecting the intake air amount in the intake passage 34, and an O2 sensor 102 for detecting the oxygen concentration in the exhaust gas in the exhaust passage 44. And a vehicle speed sensor 104 for detecting the vehicle speed is provided.

The EGR control valve 50, fuel injection valve 58, fuel pump 64, purge control valve 82, bypass air amount control valve 86, ignition coil 88, crank angle sensor 90, water temperature sensor 92, throttle sensor 94, and idle switch 96 , Intake air temperature sensor 98 and intake air amount sensor 10
The 0, O2 sensor 102, and vehicle speed sensor 104 are connected to control means 108 constituting an intake air amount control device 106. Reference numeral 110 denotes a battery.

The intake air amount control unit 106 includes a control unit 108
By controlling the bypass air amount control valve 86 according to the operating state of the engine 2, the bypass air amount is adjusted to control the intake amount of the engine 2.

Thus, the intake amount control device 106 controls the idle switch 96
By controlling the bypass air amount control valve 86 (idle control) so as to adjust the bypass air amount according to the difference between the engine speed and the target idle speed during the idling operation of the engine 2 that is turned on, the engine speed is increased. The intake air amount is controlled so that the number becomes the target idle speed.

The intake amount control device 106 is controlled by the control means 108 to fully close the throttle valve 36 from the set engine speed or higher (idle switch 96 is turned on).
During the deceleration operation, the fuel supply is stopped by controlling the fuel injection valve 58 (fuel cut control) so that the fuel is cut until the engine rotation speed reduced by the deceleration operation reaches the fuel cut return rotation speed. To control.

The intake air amount control device 106 of the engine 2
As shown in FIG. 6, the control unit 108 supplies the throttle opening signal detected by the throttle sensor 94 and the vehicle speed sensor 10
4 to output a drive signal to the bypass air amount control valve 86 to control the bypass air amount.

The intake air amount control unit 106 includes a control unit 108
Accordingly, at the time of starting the deceleration operation of the engine 2 by fully closing the throttle valve 36 (turning on the idle switch 96) from the set engine speed or more, the intake amount of the engine 2 is reduced by the throttle opening X set immediately before the full closing. The initial value Y of the deceleration bypass air amount is increased by an initial value (dashpot amount) Y of the bypass air amount for use, and the attenuation amount per unit time set according to the vehicle speed V during the deceleration operation of the engine 2. The bypass air amount control valve 86 is controlled (dashpot control) so that the time is attenuated by Z.

At this time, the control means 108 controls the engine 2
The attenuation Z is set according to the vehicle speed V at the start of the deceleration operation of the vehicle. As shown in FIG. 3, the attenuation Z is set such that the lower the vehicle speed V at the start of the deceleration operation, the greater the attenuation Z per unit time (V1 <V2 <... <Vn-1 <Vn, Z1).
> Z2 >> ... Zn-1> Zn), and the initial value Y of the deceleration bypass air amount is set to be zero by the time of returning to the fuel cut in the deceleration operation. As shown in FIG. 2, the initial value Y of the deceleration bypass air amount is set so as to increase as the throttle opening X immediately before full closure increases.
1 <X2 <... <Xn-1 <Xn, Y1 <Y2 <... <Yn-1
<Yn).

Next, the operation of this embodiment will be described. As shown in FIG. 1, when the control (dashpot control) is started (200) at or above the set engine speed by the control means 108 as shown in FIG. 1, the intake amount control device 106 reads the throttle opening X. (202), as shown in FIG. 2, an initial value (dashpot amount) Y of the deceleration bypass air amount is set from the throttle opening X, the bypass air amount control valve 86 is opened (204), and the throttle valve 36 is fully closed. Is determined (206).

If the determination (206) is NO, the process returns to reading the throttle opening X (202). If the determination (206) is YES, the deceleration operation is started, and the initial value (dashpot amount) Y of the deceleration bypass air amount set by the throttle opening X immediately before full closure is increased.

Next, the vehicle speed V is read (208), and FIG.
(210), and controls the bypass air amount control valve 86 so as to attenuate the initial value Y by the amount of attenuation Z during the deceleration operation (212). Then, when the initial value Y becomes zero, the process ends (214).

At this time, as shown in FIG.
The vehicle speed V at the start of the control is set such that the lower the vehicle speed V at the start of the deceleration operation of the engine 2, the greater the attenuation Z per unit time. As a result, the intake air amount control device 106 can slowly attenuate the deceleration bypass air amount during deceleration operation from a high vehicle speed as shown in FIG. 4, and quickly attenuate the deceleration bypass air amount during deceleration operation from a low vehicle speed. be able to.

As described above, when the deceleration operation of the engine 2 is started by the control means 108, the intake air amount control device 106 of the engine 2 reduces the intake air amount of the engine 2 just before the throttle valve 36 is fully closed. The deceleration bypass air amount is increased by an initial value Y set by the degree X, and the initial value Y is decreased by the amount of attenuation Z per unit time set according to the vehicle speed V during the deceleration operation of the engine 2. The bypass air amount control valve 36 is controlled so as to perform the control.

Thus, the intake air amount control device 106 sets the initial value Y of the deceleration bypass air amount set by the throttle opening X at the start of the deceleration operation of the engine 2 according to the vehicle speed V by the time of fuel cutback. It can be attenuated to zero, and the amount of bypass air for deceleration can be secured in accordance with the level of the vehicle speed V during deceleration operation.

For this reason, the intake air amount control device 106 of the engine 2 can attenuate the initial value Y of the deceleration bypass air amount to be zero by the time of returning from the fuel cut. By being able to secure the deceleration bypass air amount according to the level of the vehicle speed V,
During the deceleration operation of the engine 2 from the high vehicle speed V, the deceleration shock due to the full closing of the throttle valve 36 can be reduced, and the temperature of the catalyst 46 can be prevented from rising.
The deceleration bypass air amount can be reduced to zero by the time of fuel cut return without deteriorating the sense of deceleration of the vehicle during the deceleration operation of the engine 2 from above, and the occurrence of a return shock can be prevented.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified. For example, as shown in FIG. 2, the initial value Y of the deceleration bypass air amount in the above embodiment is the throttle opening X just before the throttle valve 36 is fully closed.
Can be set small when the closing speed of the throttle valve 36 is fast, and can be set large when the closing speed is slow. The attenuation Z in the above embodiment is
Although the setting is made based on the vehicle speed V at the start of the deceleration operation, it can be changed according to the engine speed or the vehicle speed that decreases during the deceleration operation.

In the above embodiment, the engine 2
By controlling the bypass air amount control valve 86 during the deceleration operation of the engine 2, the intake air amount during the deceleration operation of the engine 2 is controlled to prevent the deceleration shock and the return shock, but the bypass air amount control valve 86 cannot be used for some reason. In the case of a situation, a clutch (not shown) connected to the engine 2 or a clutch mechanism (not shown) of the automatic transmission is controlled to be in a semi-coupled state, thereby preventing a deceleration shock and a return shock. Can also.

[0038]

As described above, the engine intake air amount control apparatus according to the present invention sets the initial value of the deceleration bypass air amount at the start of the engine deceleration operation to zero before returning to the fuel cut state in accordance with the vehicle speed. And the amount of deceleration bypass air can be secured in accordance with the vehicle speed during deceleration operation.

For this reason, the intake air amount control device for the engine can reduce the deceleration shock due to the full closing of the throttle valve during the deceleration operation of the engine from a high vehicle speed, can prevent the catalyst temperature from rising, and can reduce the catalyst speed from a low vehicle speed. It is possible to prevent the occurrence of the return shock at the time of returning from the fuel cut without deteriorating the deceleration feeling of the vehicle during the deceleration operation of the engine.

[Brief description of the drawings]

FIG. 1 is a flowchart of control of an intake air amount control device for an engine according to an embodiment of the present invention.

FIG. 2 is a diagram showing a map of an initial value of a deceleration bypass air amount set by a throttle opening.

FIG. 3 is a diagram showing a map of an attenuation amount set according to a vehicle speed.

FIG. 4 is a time chart of a bypass air amount and a throttle opening in a deceleration operation from a high vehicle speed.

FIG. 5 is a time chart of a bypass air amount and a throttle opening in a deceleration operation from a low vehicle speed.

FIG. 6 is a block diagram of the intake air amount control device.

FIG. 7 is a system configuration diagram of an intake air amount control device.

FIG. 8 is a time chart of a bypass air amount and a throttle opening in a deceleration operation showing a conventional example.

FIG. 9 is a time chart of an engine speed, a bypass air amount, a fuel cut, and a throttle opening in a deceleration operation.

[Explanation of symbols]

 2 Engine 34 Intake passage 36 Throttle valve 86 Bypass air amount control valve 90 Crank angle sensor 94 Throttle sensor 96 Idle switch 104 Vehicle speed sensor 106 Intake amount control device 108 Control means

Claims (2)

[Claims] 1. A bypass passage bypassing a throttle valve is provided in an intake passage of an engine mounted on a vehicle, a bypass air amount control valve for adjusting a bypass air amount of the bypass passage is provided, and a throttle opening of the throttle valve is provided. A throttle sensor for detecting the speed of the vehicle is provided, and when the deceleration operation of the engine is started by fully closing the throttle valve, the intake air amount of the engine is set by the throttle opening just before the fully closed state. The bypass air amount control valve is increased so as to increase by an initial value of the deceleration bypass air amount, and attenuates the initial value by the amount of attenuation per unit time set according to the vehicle speed during the deceleration operation of the engine. An intake air amount control device for an engine, further comprising control means for controlling. 2. The engine intake air amount according to claim 1, wherein the control unit sets the amount of attenuation per unit time as the vehicle speed at the start of the deceleration operation of the engine is lower. Control device.