JP2547561B2 - Engine controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device, and particularly to a factor that governs an engine driving state such as an air-fuel ratio or an engine speed in a specific operating state. The present invention relates to a control device configured to perform so-called learning control for controlling the drive governing factor based on a stored value of a control amount.

(Prior Art) An engine adapted to perform learning control in vehicle control is known. Learning control is performed when a relatively stable driving state continues in a specific driving range.
The control amount at that time is stored, and next, when the same operating state as this operating state is encountered, the stored value is adopted and control is performed without newly calculating the controlled amount. As a result, it is possible to improve the control response and obtain good results in terms of control stability.

For example, Japanese Patent Laid-Open No. 59-196942 discloses an engine air-fuel ratio control device that combines feedback control and learning control.

(Problems to be Solved) Specifically, the air-fuel ratio control disclosed in JP-A-59-196942 detects the intake air intake amount, and based on the detected value, a predetermined air-fuel ratio is set. Therefore, the fuel supply amount is determined so that the fuel is supplied to the engine.

In this case, the intake air intake amount is the method of detecting the intake negative pressure,
It can be detected by a method such as a method using a hot wire.

By the way, in an engine provided with a brake device having a booster device that uses intake negative pressure, air used for brake operation is discharged into intake air that has passed through an air flow sensor when the brake device is released. As a result, an error occurs between the detected intake air intake amount and the actual intake air amount, which causes a problem that proper engine control cannot be performed.

(Means for Solving Problems) The present invention is configured in view of the above circumstances, and in an engine adapted to perform this learning control at the same time as feedback control of factors that govern various driving states of an automobile. An object of the present invention is to provide an engine control device capable of performing appropriate control by effectively eliminating the influence of the operation of a brake device equipped with a booster.

The engine control device of the present invention comprises an operating state detecting means for detecting an operating state of the engine, a target value setting means for setting a target value of a drive control factor of the engine according to the operating state, and a target value setting means of the target value setting means. Control amount setting means for setting the control amount according to the output, value detecting means for detecting the value of the drive controlling factor, and feedback correction for correcting the output of the control amount setting means according to the output from the value detecting means. Means and
A learning control means for storing and learning the control amount in a predetermined operating state and controlling the value of the drive control factor based on the learned value, and a booster utilizing the intake negative pressure downstream of the throttle valve are provided. Brake device, brake operation detecting means for detecting whether or not the brake device is in an operating state, and learning prohibition for prohibiting learning by the learning control means when deactivation of the brake device is detected by the brake operation detecting means And means.

(Operation) The control of the present invention can be applied to, for example, air-fuel ratio control or engine speed control.

In the air-fuel ratio control, air-fuel ratio setting means for setting the air-fuel ratio according to the operating state, air-fuel ratio detection means for detecting the actual air-fuel ratio, and basic air-fuel ratio according to the output from the air-fuel ratio setting means. The basic air-fuel ratio control amount setting means for setting the control amount of the fuel ratio, and the correction control amount is set so that the air-fuel ratio becomes the target air-fuel ratio based on the output from the air-fuel ratio detecting means, and the output of the basic air-fuel ratio setting means And a feedback correction means for correcting the above, and an air-fuel ratio learning control means for storing and learning the control amount in a predetermined operating state and controlling the air-fuel ratio based on the learned value. And the learning prohibition means
When the release of the brake device is detected by the brake operation detecting means, the learning by the air-fuel ratio learning control means is prohibited.

That is, in an engine in which learning control of the air-fuel ratio is performed, learning of the air-fuel ratio control amount is not performed for a predetermined period after the brake device having the booster is deactivated.

Further, the present invention controls the fuel supply amount and the intake air amount so that the engine speed converges to a predetermined value during a specific operation such as an idling operation or a low load near the idling operation, a low rotation speed. It can also be applied to rotation speed control. In this case, when the rotation speed learning control is performed and the brake device is operated and released, the learning control is prohibited for a predetermined period after the release.

In a vehicle equipped with an automatic transmission, even when the shift position is in the drive range and the vehicle is in a non-running state, braking operation is required to maintain the stopped state. From such a state, even when the brake is released for traveling, the intake / intake air amount varies, so learning is prohibited.

(Effect of the invention) According to the present invention, when learning control is adversely affected when air from the booster is introduced into the intake system of the engine by releasing the brake device as described above,
Since learning is prohibited, a proper learning value can always be stored, so that proper learning control can be performed. Therefore, the advantages of learning control can be effectively enjoyed.

(Description of Embodiments) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Referring to FIG. 1, a piston 2 is slidably housed inside an engine 1 of this embodiment.
The upper space of the above constitutes the combustion chamber 3. This combustion chamber 3
The intake passage 4 and the exhaust passage 5 communicate with each other, and the intake valve 6 and the exhaust valve 7 are associated with the respective ports of the passages 4 and 5.

An air cleaner 8 is attached to the upstream end of the intake passage 4, and a hot wire type air flow sensor 9 is arranged downstream thereof. Downstream of the air flow sensor 9,
Throttle valve 10 is provided, and combustion chamber 3 further downstream
An injector 11 for injecting fuel is attached in the vicinity of.

Further, the intake passage 4 is provided with a bypass passage 12 that bypasses the throttle valve 10, that is, allows a predetermined amount of air to flow even when the throttle valve 10 is fully closed. The bypass passage 12 is provided with a flow rate adjusting valve 13 for adjusting the flow rate.

In addition to the engine 1, a water temperature sensor 14 for detecting the cooling water temperature of the engine 1 and a rotation sensor 15 for detecting the engine speed are attached.

Further, a transmission (a manual transmission in this example) 16 connected to the engine 1 is provided with a shift sensor 17 for detecting its shift position.

The vehicle of this example is provided with a booster, that is, a master back 18, in the brake device. This Masterback 18 is
The braking force is increased by using the intake negative pressure.

Further, the engine 1 of this example is preferably configured to include a microcomputer that outputs a signal for controlling fuel injection to the injector 11 and a control signal for adjusting the opening degree of the flow rate adjusting valve 13 of the bypass passage 12. A control unit 19 is provided.

The control unit 19 includes a signal indicating the intake air amount from the air flow sensor 9, a signal indicating the opening of the throttle valve 10, a signal from the water temperature sensor 14, a signal from the rotation sensor 15 for obtaining the engine speed, and a gear change. A signal from a shift sensor 17 that detects the shift position of the machine 16, a vehicle speed sensor 20 that detects the vehicle speed, and an O ₂ in the exhaust gas installed in the exhaust system
The signal from the sensor 21 and the signal from the brake sensor 23 that detects the operation of the brake pedal 22 and detects the release of the brake device are input.

Referring to FIG. 2, the master bag 18 is integrated with a cylindrical casing 24 and a power piston which is slidably disposed in the casing 24 and divides a space in the casing 24 into a chamber 25 and a chamber 26. Equipped with a diaphragm 27.

The diaphragm 27 is connected to an input-side piston 28 that extends through the chamber 26 to the outside of the casing 24 and is connected to the brake pedal 22, and an output-side piston 29 that extends to the outside of the casing 24 through the chamber 25. There is.

A valve 30 is attached to the end of the casing 24 on the chamber 26 side, and the valve 30 is biased toward the diaphragm 27 by a spring 31 interposed between the valve 30 and the input side piston 28.

A valve 32 is attached to the input side piston 28 so that the valve 32 can be engaged with the valve 30.
Is urged toward the valve 30 by a spring 33.

Chamber 25 and chamber 26 are in communication by passages 34 and 35.

Further, the diaphragm 27 is biased toward the input side piston 28 side by a spring 36 arranged in the chamber 25. The chamber 25 communicates with the intake passage 4 by a passage 37. That is, the intake negative pressure is introduced.

When the brake pedal 22 is not depressed, the valve 30 is in contact with the valve 32. In this state, the chamber 25 and the chamber 26 communicate with each other but are shielded from the atmosphere. Therefore, the intake negative pressure is introduced into the chambers 25 and 26.

When the brake pedal 22 is depressed, the valve 32
34 is cut off to cut off communication between the chamber 25 and the chamber 26. Then, when the brake pedal 22 is further depressed, the contact state between the valves 30 and 32 is cut off, and the atmosphere is introduced into the chamber 26 through the passage 34.

As a result, the urging force of the chamber 26 becomes larger than that of the chamber 25, and the diaphragm 27, that is, the power piston, moves to the left in the figure to realize the brake operating state.

When the brake pedal 22 is no longer depressed,
Valves 30 and 32 are in contact again and the atmosphere and chamber
26 and shut off. Then, the passage 34 and the valve 32 are opened to allow the chambers 25 and 26 to communicate with each other. As a result, the air introduced into the chamber 26 flows into the chamber 25, and both chambers 2
5 and 26 are in balance. As a result, the operating state of the brake device is released.

In this case, since the atmosphere introduced into the chamber 25 is introduced into the intake system via the passage 37, intake air that is not detected by the air flow sensor 9 is introduced into the combustion chamber 3 of the engine, and It will affect the operation.

Referring to FIG. 3, a circuit configuration of the control unit 19 is shown. The control unit 19 sets the target air-fuel ratio from the intake air intake amount and the engine speed,
Based on this, the basic injection pulse width calculation circuit 38 for calculating the basic fuel injection pulse width, the engine speed, the throttle opening, the shift position, and the vehicle speed when the certain conditions are satisfied from the vehicle speed, the learning of the air-fuel ratio is performed. An air-fuel ratio learning execution determination determination circuit 39 that determines whether or not to perform the determination, an output of the air-fuel ratio learning execution determination determination circuit 39, and an air for correcting the target air-fuel ratio based on the output of the O ₂ sensor An air-fuel ratio learning calculation circuit 40 for calculating a fuel ratio learning value and an injection pulse width calculation circuit 41 for calculating a pulse width of the final fuel injection amount are provided. Then, a fuel injection amount signal is output to the injector 11 at a predetermined timing according to the calculation result of the injection pulse width calculation circuit 23.

Next, an example of air-fuel ratio control will be described with reference to FIGS. 4 and 5.

First, in FIG. 4, the control unit 19 determines whether or not the operating condition satisfies the condition for performing feedback control of the air-fuel ratio.

If this determination is YES, the control unit 19
Then, the feedback correction coefficient CFB (n) is calculated by adding or subtracting the predetermined control amount I to the current value according to the output from the O ₂ sensor 21, and the value is updated.

This value is for correcting the basic pulse width of the fuel calculated by the basic fuel injection pulse width calculation circuit 38, and the injection pulse width calculation circuit 23 calculates the final injection pulse width according to this correction coefficient. Then, the command signal is output to the injector 11.

Further, referring to FIG. 5, the control unit 19
Detects whether the opening of the throttle valve 10 is less than or equal to a predetermined value, and if it is less than or equal to a predetermined value, determines whether the learning prohibition condition is satisfied from the operating state of the brake device. If it is not prohibited, the air-fuel ratio is learned. In this case, after confirming with the parameter i that the state satisfying the learning condition for a certain period of time continues,
The learning value correction coefficient CFB is calculated by averaging the feedback control correction coefficient CFB (n) obtained according to the control shown in the figure. Then, the learning value correction coefficient is calculated using a predetermined arithmetic expression.
The learning value is updated by correcting the current learning value C (n) based on CFB and setting a new learning value.

This learning value is the same as the feedback correction coefficient CFB (n) when a predetermined condition is satisfied, or
Instead of (n), it is used, for example, as in the following formula for calculating the fuel injection pulse.

_{T = T B × (CFB (} n) + C (n) ...) ( here, T _B is the basic injection amount) Thus, it is possible to improve the responsiveness and stability of the feedback control.

Then, in this example, when the operation of the brake device is released and the air in the master bag 18 is introduced, the learning is prohibited, so that the learning control can always be performed with good accuracy. it can.

In the above description, the present invention is applied to the air-fuel ratio feedback control. However, the present invention is not limited to such a range, and is effectively applied to the engine speed feedback control. can do.

For example, in an engine equipped with an automatic transmission and configured to set a target rotation speed when the engine load is equal to or lower than a predetermined value and perform learning control of the fuel supply amount so as to reach this rotation speed, first, Learning is prohibited when the vehicle is in the driving range and the brake is released.

Not only for vehicles equipped with an automatic transmission, but for engines that have started learning control of the fuel supply amount so that the target rotation speed is achieved during idle operation or low load operation close to idle operation, If any one of the above applies, learning is prohibited.

(1) A few seconds after the throttle valve is fully closed.

(2) When the throttle valve is continuously closed for a few seconds.

(3) When the engine cooling water temperature is 80 ° C or lower.

(4) When the engine speed is 1000 or more.

(5) Several seconds after starting.

By providing such a prohibition condition, more reliable learning control can be performed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an engine equipped with a control device according to the present invention, FIG. 2 is a sectional view of a booster applicable to the present invention, FIG. 3 is a block diagram of a control unit, 4 and 5 are flow charts showing the control contents of the apparatus according to the present invention. 1 ... Engine, 2 ... Piston, 3 ... Combustion chamber, 4 ... Intake passage, 5 ... Exhaust passage, 6 ... Intake valve, 7 ... Exhaust valve, 8 ... Air cleaner, 9 ... Air flow sensor , 10 ... Throttle valve, 11 ... Injector, 12 ... Bypass passage, 13 ... Flow control valve, 14 ... Water temperature sensor, 15 ... Rotation sensor, 16 ... Transmission, 17 ... Shift sensor, 18 ...... Master bat 19 ...... Control unit, 20 ...... Vehicle speed sensor.

Claims (3)

(57) [Claims] 1. A driving state detecting means for detecting a driving state of an engine, a target value setting means for setting a target value of a driving control factor of an engine according to the driving state, and a output of the target value setting means. A control amount setting means for setting a control amount, a value detecting means for detecting the value of the drive governing factor, a feedback correcting means for correcting the output of the control amount setting means according to the output from the value detecting means, and a predetermined value In the operating state, the control amount is stored and learned, and the learning control means that controls the value of the drive control factor based on the learned value, and the brake device including the booster that uses the intake negative pressure downstream of the throttle valve A brake operation detecting means for detecting whether or not the brake device is in an operating state, and the learning control hand when the brake device operation release is detected by the brake operation detecting means. The engine control apparatus being characterized in that a learning prohibition means for prohibiting the learning. 2. The engine control device according to claim 1, wherein the drive controlling factor is an air-fuel ratio. 3. The engine control device according to claim 1, wherein the drive controlling factor is an engine speed.