JP2004003495A - Throttle control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain optimum responsiveness and stability of a throttle valve according to a running condition of a vehicle. <P>SOLUTION: In an ECU 10, the feedback control to a DC motor 12 is performed via a motor drive circuit 11 through a PID control by a PID control circuit 10b so that the difference between the actual throttle opening θth calculated based on the throttle opening signal TH of a throttle opening sensor 4 corresponding to the throttle opening of a throttle valve 3 and the throttle opening command value θcmd calculated based on the accelerator opening signal Ap of an accelerator opening sensor 6 corresponding to the accelerator opening of an accelerator pedal 5 is eliminated. The system performance is improved by setting PID control constants Kp, Ti and Td in the PID control according to a running condition of a vehicle. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a throttle control device for an internal combustion engine that controls a degree of opening of a throttle valve by driving a DC motor in accordance with an amount of depression of an accelerator pedal.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a throttle control device for an internal combustion engine called an “electronic throttle system” that controls a degree of opening of a throttle valve by driving a DC motor in accordance with an amount of depression of an accelerator pedal.
[0003]
In this throttle control device for an internal combustion engine, a current is supplied to a DC motor in accordance with a signal from an accelerator opening sensor that detects an accelerator opening corresponding to the amount of depression of an accelerator pedal, and the throttle is driven by driving the DC motor. The valve is opened and closed to control the amount of intake air. At this time, proportional / integral / differential control (hereinafter, simply referred to as "the signal") is performed on the DC motor so that the deviation between the signal from the throttle opening sensor for detecting the throttle opening of the throttle valve and the signal from the accelerator opening sensor is eliminated. PID control ”).
[0004]
[Problems to be solved by the invention]
Incidentally, the control constants of the P (proportional) term, I (integral) term, and D (differential) term in the above-described PID control are set to fixed values by intermediate tuning so as to satisfy the specifications in all operating states of the system. It had been. Of course, the control constants set in this way cannot be the optimum values corresponding to the predetermined operation state, and thus have been a factor for reducing the responsiveness and stability of the throttle valve.
[0005]
Here, the responsiveness and stability of the throttle valve required according to the driving state of the vehicle will be described.
[0006]
For example, during cruise control (hereinafter, simply referred to as "C / C") that enables the vehicle to travel at a constant speed without operating the accelerator pedal, the responsiveness and stability of the throttle valve are comparable. Is required.
[0007]
Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide a throttle control device for an internal combustion engine that can obtain optimum throttle valve responsiveness and stability according to a vehicle operating condition. And
[0008]
[Means for Solving the Problems]
A throttle control device for an internal combustion engine according to claim 1 drives a DC motor in accordance with an amount of depression of an accelerator pedal to control an opening of a throttle valve. , And control constant setting means for setting the control constants of the proportional / integral / differential control as the operating state of the vehicle in accordance with the C / C time.
[0009]
The throttle control device for an internal combustion engine according to claim 2 further includes C / C determination means for determining the C / C time of the internal combustion engine, and the control constant setting means uses the C / C determination means by the C / C determination means. When it is determined, the proportional term gain and the derivative term gain of the control constants in the proportional, integral, and differential are set to approximately the same levels as those in the normal state.
[0010]
According to a third aspect of the present invention, there is provided a throttle control device for an internal combustion engine, wherein the control constant setting means smoothes and sets the control constant in addition to the means provided in any one of the first and second aspects.
[0011]
[Action]
In the throttle control apparatus for an internal combustion engine according to the first aspect, the DC motor is PID-controlled by the throttle valve control means to control the throttle valve. The control constant in the PID control is set by the control constant setting means as the operating state of the vehicle corresponding to the C / C time. In such PID control, the control constant can be set to an optimum value corresponding to C / C as the operating state of the vehicle.
[0012]
In the control constant setting means of the throttle control device for an internal combustion engine according to the second aspect, in addition to the operation of the first aspect, when the C / C determination means determines that the vehicle is in the C / C time, a specific operation state of the vehicle is determined. The P (proportional) term gain and the D (differential) term gain of the control constant at the time of C / C are set to be approximately the same as those in the normal state.
[0013]
In the control constant setting means of the throttle control device for an internal combustion engine according to the third aspect, in addition to the first or second aspect, the control constant is smoothed and set.
[0014]
【Example】
Hereinafter, the present invention will be described based on specific examples.
[0015]
FIG. 1 is a schematic diagram showing an overall configuration of a throttle control device for an internal combustion engine according to one embodiment of the present invention.
[0016]
In FIG. 1, reference numeral 1 denotes an internal combustion engine, and air is supplied to the internal combustion engine 1 through an intake passage 2. Reference numeral 3 denotes a throttle valve. The throttle valve 3 is provided in the middle of the intake passage 2. The throttle valve 3 is provided with a throttle opening sensor 4 for detecting a throttle opening. Reference numeral 5 denotes an accelerator pedal, and the accelerator pedal 5 is provided with an accelerator opening sensor 6 for detecting an accelerator opening. Reference numeral 7 denotes a fully closed stopper that regulates the fully closed position of the throttle valve 3.
[0017]
Reference numeral 10 denotes an ECU (Electronic Control Unit). The ECU 10 receives a throttle opening signal TH from the throttle opening sensor 4 and an accelerator opening signal Ap from the accelerator pedal 5. Reference numeral 12 denotes a DC motor as an actuator, and a current is supplied to the DC motor 12 from the ECU 10 side. Reference numeral 13 denotes a gear disposed between the DC motor 12 and the throttle valve 3, and reference numeral 14 denotes a return spring that constantly urges the throttle valve 3 to the fully closed side.
[0018]
Next, a description will be given with reference to FIG. 2 showing a main configuration of a throttle control device for an internal combustion engine according to one embodiment of the present invention, and FIG. 3 showing a signal flow in feedback control.
[0019]
2, the accelerator opening signal Ap from the accelerator opening sensor 6 corresponding to the depression amount of the accelerator pedal 5 and the throttle opening signal TH from the throttle opening sensor 4 corresponding to the throttle opening of the throttle valve 3 are A. The signal is A / D converted by the / D converter 10a and input to the ECU 10. A PWM (Pulse Width Modulation: Pulse Width Modulation) signal is output from the ECU 10 to the motor drive circuit 11 according to these signals. Then, a current flows from the motor drive circuit 11 to the DC motor 12, and the DC motor 12 is driven to open and close the throttle valve 3 via the gear 13.
[0020]
At this time, as shown in FIG. 3, the ECU 10 calculates the actual throttle opening θth calculated based on the throttle opening signal TH of the throttle opening sensor 4 corresponding to the throttle opening of the throttle valve 3 and the actual throttle opening θth of the accelerator pedal 5. Through the PID control by the PID control circuit 10b through the motor drive circuit 11 so that there is no deviation from the throttle opening command value θcmd calculated based on the accelerator opening signal Ap of the accelerator opening sensor 6 corresponding to the accelerator opening. Thus, the feedback control for the DC motor 12 is executed.
[0021]
Next, the relationship between the P-term gain, I-term gain, and D-term gain, which are the control constants of the P (proportional) term, the I (integral) term, and the D (differential) term in the PID control, and the control characteristics of the throttle valve will be described. explain.
[0022]
The P-term gain controls the rising or falling slope in opening and closing the throttle valve, that is, the response speed. Therefore, as the P-term gain increases, the response speed of the throttle valve increases, but overshoot as a reaction increases, and oscillation tends to occur if the throttle opening is kept constant.
[0023]
The I-term gain is controlled so as to reduce the deviation between the throttle opening command value of the throttle valve and the actual throttle opening. Therefore, when the I-term gain increases, the behavior of the throttle valve increases, and oscillation tends to occur when the throttle opening is kept constant.
[0024]
The D term gain controls the final convergence speed related to the response speed in opening and closing the throttle valve. Therefore, when the D-term gain increases, the response speed of the throttle valve decreases, but on the other hand, the overshoot of the throttle valve when the throttle opening varies is reduced.
[0025]
Next, the processing procedure of the ECU 10 used in the throttle control device for an internal combustion engine according to one embodiment of the present invention will be described with reference to the flowcharts of FIGS. Will be explained.
[0026]
First, in step S101, it is determined whether the time T1 (4 ms to 8 ms) has elapsed from the previous determination. When the determination condition in step S101 is not satisfied, the present routine ends. On the other hand, when the determination condition of step S101 is satisfied, the process proceeds to step S102, and it is determined whether or not TRC is being performed based on the slip state of the wheel. If the determination condition of step S102 is satisfied, that is, if (wheel speed of driving wheel)> (wheel speed of driven wheel), it is determined that the vehicle is slipping and TRC is in progress, and the process proceeds to step S103. A PID control constant is obtained from the TRC map shown.
[0027]
On the other hand, when the determination condition of step S102 is not satisfied, the process proceeds to step S104, and it is determined whether the C / C is being performed. Here, if the C / C main switch is ON and the C / C set switch is ON, the C / C starts and the C / C is in progress. It ends. When the determination condition in step S104 is satisfied, the process proceeds to step S105, and a PID control constant is obtained from the C / C map shown in FIG.
[0028]
If the determination condition in step S104 is not satisfied, the process proceeds to step S106, and it is determined whether or not ISC is being performed. As a determination condition during this ISC, if the vehicle speed = 0 and (throttle opening) ≦ (predetermined opening), the ISC is started and the ISC is in progress. When the determination condition of step S106 is satisfied, the process proceeds to step S107, and a PID control constant is obtained from the ISC map shown in FIG.
[0029]
If the determination condition in step S106 is not satisfied, the process proceeds to step S108, and the PID control constant is obtained from the normal map shown in FIG. After the processing of step S103, step S105, step S107 or step S108, the process proceeds to step S109, where the PID control constant is smoothed, and this routine ends.
[0030]
In addition, as the smoothing of the PID control constant, a method according to the following equations (1), (2), and (3) called exponential smoothing is used. Here, ρ is a constant preset from 0 <ρ <1 as a filter constant. As can be seen from the following equations (1), (2), and (3), the larger the value of ρ, the sharper the value. It will be asymptotic to the new PID control constant.
[0031]
[Equation 1]
Kpn = (1−ρ) Kpn−1 + ρKpt (1)
[Equation 2]
Tdn = (1−ρ) Tdn−1 + ρTdt (2)
[Equation 3]
Tin = (1−ρ) Tin−1 + ρTit (3)
In this manner, the P (proportional) term gain Kp, the D (differential) term gain Td, and the I (integral) term gain Ti in the PID control are obtained from the above equations (1), (2), and (3). The PID control equation G in the PID control circuit 10b of the ECU 10 in FIG. Here, S is a Laplace operator.
[0032]
[Equation 4]
G = Kp {1+ (1 / TiS) + TdS} (4)
Note that the PID represented by the above equation (4) is a general equation, and can be similarly applied to PID control represented by another special equation.
[0033]
As described above, the throttle control device for the internal combustion engine according to the present embodiment drives the DC motor 12 in accordance with the depression amount of the accelerator pedal 5 to control the opening of the throttle valve 3, and performs the PID control of the DC motor 12. And a control constant setting means achieved by the ECU 10 for setting a control constant of the PID control according to the driving state of the vehicle. is there.
[0034]
Therefore, the throttle valve 3 is controlled by the PID control of the DC motor 12 by the throttle valve control means, and the control constant in the PID control is set by the control constant setting means according to the driving state of the vehicle. Therefore, in such PID control, the control constant can be set to an optimum value corresponding to the driving state of the vehicle to improve the performance of the system.
[0035]
Further, in the throttle control device for an internal combustion engine according to the present embodiment, the control constant setting means achieved by the ECU 10 sets the control constant at the time of the ISC.
[0036]
Therefore, the control constant at the time of the specific ISC is set as the driving state of the vehicle by the control constant setting means. That is, at the time of ISC, the D (differential) term gain in the PID control is set large and the P (proportional) term gain is set small. Therefore, the stability of the throttle valve is emphasized, and the control is suitable for stabilizing the engine speed at the time of idling of the internal combustion engine.
[0037]
In the throttle control device for an internal combustion engine according to the present embodiment, the control constant setting means achieved by the ECU 10 sets the control constant at the time of TRC.
[0038]
Therefore, a control constant at the time of TRC is set as the operating state of the vehicle by the control constant setting means. That is, at the time of TRC, the P (proportional) term gain in the PID control is set large and the D (differential) term gain is set small. For this reason, the responsiveness of the throttle valve is emphasized, and the control is suitable for quickly changing the driving force of the driving wheel by the output of the internal combustion engine according to the road surface condition or the like.
[0039]
Further, in the throttle control device for an internal combustion engine according to the present embodiment, the control constant setting means achieved by the ECU 10 sets the control constant at the time of C / C.
[0040]
Accordingly, the control constant setting means sets a specific control constant at the time of C / C as the operating state of the vehicle. That is, at the time of C / C, the P (proportional) term gain and the D (differential) term gain in the PID control are set to the same level. For this reason, the responsiveness and stability of the throttle valve are emphasized, and the control is suitable for constant speed traveling of the vehicle.
[0041]
Further, in the throttle control device for an internal combustion engine according to the present embodiment, the control constant setting means achieved by the ECU 10 smoothes and sets the control constant.
[0042]
Therefore, the control constant is smoothed and set by the control constant setting means. For this reason, even if the driving state of the vehicle is suddenly changed, it is possible to avoid a sudden change in the PID control constant, and to prevent unnatural behavior of the vehicle.
[0043]
By the way, in the above embodiment, the PID control constant at the time of ISC, TRC, and C / C is set as the operating state of the vehicle. However, the present invention is not limited to this. However, even in other driving states of the vehicle, optimum throttle valve responsiveness and stability can be obtained by setting PID control constants in a similar map.
[0044]
【The invention's effect】
As described above, according to the throttle control apparatus for an internal combustion engine of the first aspect, the control constant at the time of C / C is set as the control setting means. More specifically, the response of the throttle valve is set by setting the P (proportional) term gain and the D (differential) term gain in the PID control to the same level at the time of C / C as described in claim 2. In addition, it is possible to perform control suitable for constant-speed running of the vehicle with emphasis on stability and stability.
[0045]
According to the throttle control device for an internal combustion engine of the third aspect, in addition to the effect of the first or second aspect, the control constant is smoothed and set by the control constant setting means. As a result, even when the driving state of the vehicle is suddenly changed, it is possible to avoid a sudden change in the control constant in the PID control, and to prevent unnatural behavior of the vehicle.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an overall configuration of a throttle control device for an internal combustion engine according to one embodiment of the present invention.
FIG. 2 is a block diagram showing a main configuration of a throttle control device for an internal combustion engine according to one embodiment of the present invention.
FIG. 3 is an explanatory diagram showing a signal flow in a throttle control device for an internal combustion engine according to one embodiment of the present invention.
FIG. 4 is a flowchart showing a processing procedure of an ECU used in a throttle control device for an internal combustion engine according to one embodiment of the present invention.
FIG. 5 is a map showing control constants in each operation state used in the throttle control device for the internal combustion engine according to one embodiment of the present invention.
[Explanation of symbols]
Reference Signs List 1 internal combustion engine 3 throttle valve 4 throttle opening sensor 5 accelerator pedal 6 accelerator opening sensor 10 ECU (electronic control device)
10b PID control circuit 12 DC motor

Claims (3)

In a throttle control device for an internal combustion engine that drives a DC motor in accordance with an amount of depression of an accelerator pedal to control an opening degree of a throttle valve,
Throttle valve control means for controlling the throttle valve by proportional / integral / differential control of the DC motor;
And a control constant setting means for setting a control constant of said proportional / integral / differential control as an operating state of the vehicle in accordance with cruise control. Cruise control determining means for determining the cruise control time of the internal combustion engine,
The control constant setting means sets the proportional term gain and the differential term gain of the control constant in the proportional / integral / derivative to approximately the same as those in the normal state when the cruise control determining means determines that the cruise control is being performed. The throttle control device for an internal combustion engine according to claim 1, wherein: 3. The throttle control device for an internal combustion engine according to claim 1, wherein the control constant setting unit sets the control constant after smoothing the control constant.

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