KR0161700B1 - Throttle control device for internal combustion engine - Google Patents

Abstract

Provided is a throttle control device for an internal combustion engine that enables stable control of an actuator even when the detection opening degree approaches the target opening degree and the deviation is small.

If the absolute value | ER | of the ER is less than or equal to the limit ER _LM1 (S1) and the state is continuous for more than a predetermined time (S2), the control amount of the actuator may hunt. In the throttle PID operation, the derivative gain KD related to the derivative operation is set to 0, and the derivative operation is stopped (S3).

Description

Throttle Control of Internal Combustion Engine

1 is an overall system diagram of a throttle control device showing an embodiment of the present invention.

2 is a flowchart showing the contents of the throttle control according to the embodiment.

3 is a flow chart showing the control contents of the differential manipulation amount D according to the embodiment.

4 is a timeline illustrating the operation related to the above embodiment.

5 is a time line showing control contents of the differential manipulation amount D according to an embodiment other than the present invention.

6 is a timeline illustrating the operation related to the other embodiments.

* Explanation of symbols for main parts of the drawings

3: throttle valve 5: fuel injection valve

6: control unit 10: accelerator pedal

14: Throttle Actuator 15: Throttle Sensor

The present invention relates to a throttle control device for an internal combustion engine, and more particularly, to a throttle control device for driving a throttle valve by a throttle actuator such as a step motor.

Background Art Conventionally, a system called a traction control system that controls engine output torque and brake force to prevent wheel spin of a drive wheel to improve oscillation acceleration on a slippery road surface when the drive wheel of a vehicle is likely to spin the wheel has been put to practical use. (See Japanese Patent Application Laid-Open No. 4-589049).

In the traction control system, a second throttle valve which is opened and closed in accordance with an actuator such as a stepping motor is installed in series with the first throttle valve, in addition to the first throttle valve that is normally opened and closed depending on the accelerator operation. When the second throttle valve is completely opened and a predetermined traction operation condition is achieved, the second throttle valve is forcibly closed to the target opening degree.

Further, in these throttle control devices, a throttle sensor for detecting the opening degree of the second throttle valve is provided, and the opening degree of the second throttle valve is precisely controlled to the target opening degree based on the detection result of the sensor. It is supposed to be.

Further, as described above, the first throttle valve and the second throttle valve are not provided, respectively, and the throttle valve is united as disclosed in Japanese Patent Laid-Open No. 3-61654. There is also a throttle control device that can be determined by the operation of the accelerator pedal and can automatically control the opening of the throttle valve in an traction operation state by an actuator such as a stepping motor.

Also in this case, as described above, a sensor for detecting a control amount of an actuator that automatically controls the opening degree of the throttle valve is provided, and the control amount of the actuator is fed back to the target control amount with high accuracy based on the detection result of the sensor. It is supposed to be controlled.

Here, in these throttle control devices, the throttle sensor which detects the opening degree of the throttle valve driven by an actuator is provided, the deviation of the detection opening degree and target opening degree detected by the said sensor is calculated | required, and based on the deviation, PID operation (proportional operation amount P, integral operation amount I, differential operation amount D) for PID control with constant gain is performed, and the actuator is feedback-controlled based on the operation result, and the opening degree of the second throttle valve is increased. It is controlled to the degree of target opening degree.

However, in the case of performing the throttle control by calculating the deviation in this manner, if the gain value is constant in the PID operation, the program software for control becomes simple, but when the detection opening degree approaches the target opening degree and the deviation becomes small. If the deviation is slightly changed due to the noise of the sensor, the differential operation amount D of the corresponding change is calculated according to the gain, so that the differential operation amount D is greatly changed, and thus the PID operation value is greatly changed and the control amount of the actuator There is a risk of this hunting.

The present invention was devised in view of the above circumstances, and an object of the present invention is to provide a throttle control device for an internal combustion engine that enables stable control of the actuator even when the detection opening degree approaches the target opening degree and the deviation is small. do.

In order to achieve this object, a throttle control device for an internal combustion engine according to the present invention includes a throttle actuator for driving a throttle valve mounted on an engine suction machine, a throttle opening degree detecting means for detecting an opening degree of the throttle valve, and the throttle Deviation between the target opening degree setting means for setting the target opening degree of the valve and the target opening degree set by the detection opening degree and the target opening degree setting means, based on the throttle opening degree detecting means, is used, and the deviation is used. In the throttle control device of the internal combustion engine comprising a switching operation means for controlling the throttle actuator based on the operation result of the PID operation for the PID control, the PID operation compared to when the deviation is small The gain value associated with the differential operation of the powder was reduced.

The open / close control means performs PID operation for PID control based on the deviation between the actual opening degree and the target opening degree of the throttle valve, and controls the throttle actuator for driving the throttle valve.

Here, when the actual opening degree is near the target opening degree and the deviation is small, the proportional operation amount P and the integral operation amount I in the PID operation do not change greatly even if there is some variation in the deviation.

Further, the derivative operation amount D, which may change significantly even if there is a slight variation in the deviation, also decreases the gain value associated with the differential operation in the PID operation as compared with when the deviation is small, so that the actual opening degree The target opening is also near, and even when the deviation is small, the actuator can be controlled stably.

Hereinafter, embodiments of the present invention will be described.

In FIG. 1 showing the system configuration of this embodiment, air is sucked into the internal combustion engine 1 via the air cleaner 2, the throttle valve 3, and the intake manifold 4.

At each branch of the intake manifold 4, an electronic fuel injection valve 5 is provided for each cylinder, and a mixer is formed by the fuel intermittently injected from the fuel injection valve 5.

The fuel injection valve 5 is controlled to be open-driven by a control unit 6 incorporating a microcomputer. The control unit 6 receives input of the intake air flow rate signal Q from the weigh scale 7, the rotation signal N from the crank angle sensor 8, the coolant temperature Tw from the water temperature sensor 9, and the like for the fuel injection control. The fuel injection amount is calculated based on these detection signals, and the fuel injection valve 5 is intermittently opened in accordance with the calculated injection amount.

In addition, the throttle valve 3 is configured to open and close in conjunction with the operation of the accelerator pedal 10.

In addition, in the present embodiment, the control unit 6 is also supposed to function as a control unit of the traction control system. For this traction control, the drive wheel rotation sensor 12 and the non-drive wheel rotation sensor 13 are provided. Inputs a signal from the drive wheel, determines the wheel spin of the drive wheel based on the detection signals of the rotation sensors 12 and 13, and if the wheel spin is to be generated, the opening degree of the throttle valve 3 is forcibly reduced. The engine output torque is reduced and the brake force on the drive wheel side is increased to prevent the generation of wheel spins on the drive wheel.

Here, for the traction control, the opening degree of the throttle valve 3 can be automatically controlled by the throttle actuator 14 such as a stepping motor, regardless of the accelerator operation.

Then, in order to drive control the throttle valve 3 by the throttle actuator 14 to a target open road, the throttle valve 3 has a potentiometer type throttle sensor as a throttle opening degree detecting means for detecting the opening degree TVO. (15) is provided, and feedback control is made to the target opening degree based on the detection signal output from the sensor 15 corresponding to the opening degree TVO.

In this way, the control unit 6 sets the target opening degree of the throttle valve 3 for reducing the engine output torque during the traction control operation, and in accordance with the detection signal of the throttle sensor 15 to be the target opening degree, It has a function to feedback-control the throttle actuator 14. Therefore, in the present embodiment, the control unit 6 is provided with functions as target opening degree setting means and opening / closing control means.

The state of feedback control of the throttle actuator 14 is shown in the flowchart of FIG.

In the flowchart of FIG. 2, first, in step 11 (in the drawing, S11 will be described. The same applies below), the output STVO corresponding to the opening degree TVO of the throttle valve 3 detected by the throttle sensor 15 and the predetermined target opening. The deviation ER of the value TGTVO corresponding to the figure is calculated.

ER = STVO-TGTVO

In step 12, the change ratio DER of the deviation ER is obtained as the deviation between the deviation ER calculated this time and the deviation ER-1 calculated last time.

DER = ER-ER _-1

Further, in step 13, the integral value IER of the deviation ER is updated by adding the deviation ER calculated this time to the integral value IER up to the previous time.

IER = IER + ER

In step 14, the deviation ER, the integral value IER, and the change ratio DER are multiplied by the proportional gain KP, the integral gain KI, and the derivative gain KD, respectively, so that the proportional operation amount P (= KP × ER) and the integral operation amount I (= KI × IER ), And set the differential operation amount D (= KD x DER).

In step 15, the value obtained by adding the reference value 1.0 to the sum of the proportional manipulation amount P, the integral manipulation amount I, and the differential manipulation amount D is set as the opening degree control value X of the new throttle actuator 14.

X = P + I + D + 1.0

In the present embodiment, the derivative gain KD used in the PID operation of the feedback control of the throttle actuator 14 is set to 0 when the deviation ER becomes less than or equal to the predetermined value. A state in which the differential gain KD is zero is shown in the flowchart of FIG.

In step 21, it is determined whether or not the absolute value | ER | of the deviation ER calculated in step 11 is less than or equal to the limit ER _LM1 . If it is determined that | ER | ≤ER _LM1 , the process proceeds to step 22, and the absolute value | ER | is limited. It is judged whether the state below ER _LM1 is continuous for 10 msec or more.

In the case where it is judged to be yes, the actual opening degree of the throttle valve 3 is in the vicinity of the predetermined target opening degree. Therefore, the predetermined target opening degree is indicated by the output STVO corresponding to the opening degree TVO of the throttle valve 3. It is determined that the deviation ER of the value TGTVO corresponding to is small, and the process proceeds to step 23.

In step 23, when the deviation ER is slightly changed due to noise or the like, the differential operation amount D of the corresponding conversion is calculated according to the gain, so that the PID operation value varies greatly and the control amount of the actuator is hunted. Not only is there a risk of discarding, but the actual opening degree of the throttle valve 3 is near the predetermined target opening degree, and even if the differential operation amount D is 0, it does not affect the convergence degree of the actual opening degree to the target opening degree. The derivative operation is stopped by setting the derivative gain KD related to the derivative operation in the PID operation to zero.

On the other hand, in step 21, when it is determined as ERER _LM1 or when it is determined as NO in step 22, the process proceeds to step 24 and the differential operation amount D is calculated using the ordinary differential gain KD.

Therefore, also in the present embodiment, as shown in FIG. 4, even if there is some variation in the deviation ER, the differential operation amount D which may change greatly, the absolute value | ER | of the deviation ER is less than or equal to the predetermined value ER _LM1 . When the differential gain KD related to the differential operation is zero in the PID operation, the opening degree control value X of the throttle actuator 14 is close to the target opening degree. Hunting can be prevented, and therefore, it becomes possible to stably perform the feedback control of the throttle actuator 14.

In addition, in this embodiment, after confirming that | ER | is less than or equal to the limit ER _LM1 for a predetermined time (10 msec) or more, the differential gain KD related to the derivative operation is reduced. After this surely becomes small, the corresponding control is made and the hunting is certainly prevented.

In the present embodiment, the derivative operation is stopped by setting the derivative gain KD to 0 in step 23, but of course, the derivative gain KD may be set to a small value.

In addition, as another embodiment related to the present invention, the differential gain KD used in the PID operation of the feedback control of the throttle actuator 14 in FIG. 2 is changed when the deviation ER becomes less than or equal to a predetermined value. You may make it decrease with ER. In this case, the state in which the derivative gain KD is decreased is shown in the flowchart of FIG.

In step 31, it is determined whether the deviation ER calculated in step 11 is | ER | is less than or equal to the limit ER _LM2 , and when it is determined that | ER | ≤ ER _LM2 , the process proceeds to step 32.

In step 32, the actual opening degree of the throttle valve 3 is near the predetermined target opening degree. Therefore, the output STVO corresponding to the opening degree VTO of the throttle valve 3 and the value TGTVO corresponding to the predetermined target opening degree are obtained. It can be judged that the deviation ER is small, and when the deviation ER changes slightly due to noise or the like, the differential operation amount D of the corresponding change is calculated according to the gain. Since the control amount may hunt, the derivative gain KD related to the derivative operation is controlled as described below.

In other words, for example, the differential gain KD is set in proportion to the absolute value | ER | of the deviation ER so that the differential gain KD also decreases with the decrease of the deviation ER.

That is, when | ER | ≤ER _{LM2 is set} to the differential gain KD ', KD' = (| ER | / ER _LM2 ) x KD.

On the other hand, in step 31, when judged to be ERER _LM1 , it progresses to step 33 and calculates the differential operation amount D using the normal differential gain KD.

Therefore, also in the present embodiment, as shown in FIG. 6, even if there is some variation in the deviation ER, the differential operation amount D, which may change greatly, also has the absolute value | ER | of the deviation ER being less than or equal to the predetermined value ER _LM1 . In this case, the derivative gain KD related to the derivative operation in the PID operation is made smaller with the decrease in the deviation ER. Therefore, when the actual opening degree is near the target opening degree, the throttle actuator 14 It is possible to prevent the opening degree control value X of) from hunting, thus making it possible to stably perform padback control of the throttle actuator 14.

Further, in this embodiment, even when the absolute value | ER | of the deviation ER becomes small and the absolute value | ER | becomes less than or equal to the limit ER _LM2 , the derivative gain is continuously reduced, so that the effect of preventing hunting is more effective. There is.

The derivative gain is not limited to a decrease in the differential gain after the deviation becomes less than or equal to the predetermined value. For example, the configuration may be such that the differential gain is reduced in quadratic curve in accordance with the decrease in the deviation.

As described above, according to the present invention, the detection opening degree approaches the target opening degree, and thus the differential operation amount D can be prevented from greatly changing when the deviation is small, and therefore, the PID calculation value can be prevented from greatly changing. have. Therefore, there is an effect that hunting of the control amount of the actuator can be prevented and control of the actuator can be performed stably.

Claims (1)

A throttle actuator for driving a throttle valve fitted to the engine intake machine, a throttle opening degree detecting means for detecting the opening degree of the throttle valve, a target opening degree setting means for setting a target opening degree of the throttle valve, and the throttle Deviation between the detected opening degree detected by the opening degree detecting means and the target opening degree set by the target opening degree setting means is obtained, and the deviation is used to perform a PID operation for PID control, and based on the calculation result, A throttle control apparatus for an internal combustion engine comprising an opening and closing control means for controlling a throttle actuator, the internal combustion engine configured to reduce a gain associated with the differential operation in the PID operation as compared with when the deviation is small. Throttle Control.