JP2003211997A - Fixed speed running controller for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce fluctuation of vehicle speed during fixed speed running control. <P>SOLUTION: Basic control amount for controlling a degree of throttle opening in accordance with deviation of target vehicle speed and actual vehicle speed is computed by a basic control amount computation means 27 during fixed speed running control. Load compensation amount for compensating the basic control amount by load in accordance with air suction pipe pressure is computed by a load compensation amount computation means 33. Furthermore, load compensation is permitted or inhibited in accordance with difference pressure between atmospheric pressure and the air suction pipe pressure or the load compensation amount is changed by a load compensation regulation means 40. Final control amount of a degree of throttle opening is computed based on the basic control amount and the load compensation amount permitted or changed by the load compensation regulation means 40. Consequently, the situation in which a degree of throttle opening is unreasonably and continuously controlled in the direction of opening can be avoided in a region of a degree of throttle opening in which increase ratio of an engine output is saturated during fixed speed running control. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle constant speed running control device for automatically running a vehicle at a constant speed at a target vehicle speed set by a driver.

[0002]

2. Description of the Related Art Some vehicles employing an electronic throttle system in which a throttle valve is driven by an actuator such as a motor are equipped with a constant speed traveling control device (generally called a cruise control device). When the driver sets the target vehicle speed with the cruise control switch while traveling, this constant speed traveling control device ensures that the actual vehicle speed detected by the vehicle speed sensor will match the target vehicle speed thereafter without operating the accelerator pedal. In addition, the throttle opening is automatically controlled so that the vehicle runs at a constant speed at the target vehicle speed. Generally, the constant speed traveling control performs feedback control by PI control according to the deviation between the target vehicle speed and the actual vehicle speed. At this time, in order to suppress the vehicle speed change due to the change of the traveling load, the traveling load (intake pipe pressure Etc.) is detected and the P term (proportional term) and / or I of the PI control is detected according to the traveling load.
The term (integral term) is corrected, and the throttle opening is feedback-controlled so that the actual vehicle speed matches the target vehicle speed.

[0003]

By the way, as shown in FIG. 10, the relationship between the throttle opening and the engine output is as follows.
In a region below the throttle opening to some extent, the linear relationship is maintained, and the engine output increases as the throttle opening increases. There is a region (hereinafter referred to as "engine output saturation region") in which the engine output does not increase much even if the opening degree is increased. For example, if a steep uphill is approached during constant speed running control, the actual vehicle speed will not increase and the deviation between the target vehicle speed and the actual vehicle speed will not decrease even if the transmission is downshifted and operated near maximum output. There are cases. In such a case, even if the throttle opening is increased,
Although the engine output hardly increases, the I term of the PI control continues to increase and the throttle opening is controlled to be further opened. In particular, when driving at high altitudes, the engine output decreases due to a decrease in air density, and the engine output saturation range is entered with a smaller throttle opening than when driving at low altitudes. It seems that the frequency of driving will increase.

If the deviation between the target vehicle speed and the actual vehicle speed does not decrease due to an uphill or the like during the constant speed running control, the throttle opening is controlled by the I term of PI control even in the engine output saturation region. It will continue to control in the opening direction. In such a situation, when the vehicle suddenly approaches a downhill, the throttle opening is too wide (I term is too large). It takes some time to close to an appropriate throttle opening, and during that time, an excessive engine output is generated on a downhill and the vehicle is accelerated, and the actual vehicle speed greatly exceeds the target vehicle speed. There was a drawback that the fluctuation was large.

The present invention has been made in view of the above circumstances, and therefore an object thereof is to provide a constant speed running control device for a vehicle capable of performing stable constant speed running with little fluctuation in vehicle speed. It is in.

[0006]

In order to achieve the above object, a constant speed running control device for a vehicle according to claim 1 of the present invention responds to a deviation between a target vehicle speed and an actual vehicle speed during constant speed running control. The basic control amount for controlling the throttle opening is calculated by the basic control amount calculation means, and the load correction amount for correcting the basic control amount according to the traveling load detected by the traveling load detection means is loaded. It is calculated by the correction amount calculation means.
Furthermore, during constant speed running control, the load correction regulation means
The basic control amount correction (hereinafter referred to as "load correction") by the load correction amount is permitted or prohibited or the load correction amount is changed according to the operating condition of the internal combustion engine, and the basic control amount calculation means is used to change the basic control amount. A final control amount of the throttle opening is calculated based on the control amount and the load correction amount permitted or changed by the load correction regulation means, and the throttle opening is controlled by the throttle opening control means based on the final control amount. Control. By doing so, it becomes possible to prohibit the load correction or limit the load correction amount in the throttle opening area (engine output saturation area) where the increase rate of the engine output is saturated during the constant speed traveling control, In this engine output saturation region, it is possible to avoid a situation in which the throttle opening is kept controlled in the direction in which it is open unnecessarily. As a result, when the vehicle is running at a constant speed in the engine output saturation region, even if it suddenly approaches a downhill, the throttle opening does not open too much. Can be reduced to control the actual vehicle speed near the target vehicle speed. As a result, it is possible to reduce the vehicle speed fluctuation during the constant speed running control and perform stable constant speed running.

By the way, as shown in FIG. 10, in a region below a certain throttle opening, as the throttle opening is increased, the pressure difference between the intake pipe pressure and the atmospheric pressure becomes smaller.
As the engine output saturation region approaches, the engine output saturation region has a characteristic that the increase rate of the intake pipe pressure is saturated even when the throttle opening is opened.

In consideration of such characteristics, as described in claim 2, the load correction is permitted or prohibited or the load correction amount is changed according to the pressure difference between the intake pipe pressure and the atmospheric pressure. Alternatively, as in claim 3, the load correction may be permitted or prohibited or the load correction amount may be changed according to the change rate of the intake pipe pressure with respect to the change of the throttle opening. By doing so, it is possible to accurately determine whether or not the engine output is in the saturated region and perform load correction with higher accuracy.

When the basic control amount is calculated by the PI control as in claim 4, the load correction of the I term of the PI control is permitted or prohibited according to the operating condition of the internal combustion engine, or I
It is advisable to change the load correction amount of the term. In this way, the throttle opening area (engine output saturation area) where the increase rate of the engine output is saturated during constant speed traveling control
Thus, even if the deviation between the target vehicle speed and the actual vehicle speed is not reduced, it is possible to prevent the load correction amount of the I term of the PI control from unnecessarily increasing, which is a drawback of the conventional PI control. Can be resolved.

The invention according to claims 1 to 4 described above is
Direction to open the throttle opening unnecessarily by prohibiting load correction or limiting the load correction amount in the throttle opening area (engine output saturation area) where the rate of increase in engine output saturates during constant-speed running control However, instead of prohibiting the load correction or changing the load correction amount, the increase of the basic control amount is prohibited or the basic control amount is changed as described in claim 5. Or, claim 6
As described above, the same effect can be obtained by prohibiting the increase of the final control amount or changing the final control amount.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment (1)] An embodiment (1) of the present invention will be described below with reference to FIGS. 1 to 11.

First, a schematic structure of the entire engine control system will be described with reference to FIG. An air cleaner 13 is provided in the most upstream part of an intake pipe 12 of an engine 11 which is an internal combustion engine, and an air flow meter 14 for detecting an intake air amount is provided downstream of the air cleaner 13.
A throttle valve 15 driven by a motor 31 such as a DC motor is provided on the downstream side of the air flow meter 14, and the opening of the throttle valve 15 (throttle opening) is detected by a throttle opening sensor 16. During engine operation, the control amount of the drive motor 31 of the throttle valve 15 is fed back so that the actual throttle opening detected by the throttle opening sensor 16 matches the target throttle opening set according to the accelerator operation amount and the like. Control.

A surge tank 17 is provided on the downstream side of the throttle valve 15.
7, an intake pipe pressure sensor 18 for detecting the intake pipe pressure is provided. The intake pipe pressure sensor 18 also functions as a traveling load detecting means for detecting a traveling load during constant speed traveling control. In addition, the surge tank 17 has an engine 11
An intake manifold 19 that introduces air into each cylinder is provided, and a fuel injection valve 20 that injects fuel is attached near the intake port of the intake manifold 19 of each cylinder.

On the other hand, in the middle of the exhaust pipe 21 of the engine 11, a catalyst 22 such as a three-way catalyst for purifying exhaust gas is installed. An air-fuel ratio sensor (or oxygen sensor) 23 that detects the air-fuel ratio (or oxygen concentration) of the exhaust gas is provided on the upstream side of the catalyst 22. Further, a cooling water temperature sensor 24 for detecting a cooling water temperature and a rotation speed sensor 25 for detecting an engine rotation speed are attached to a cylinder block of the engine 11. Besides, a vehicle speed sensor 27 (vehicle speed detecting means) for detecting an actual vehicle speed, a cruise control switch 28 (target vehicle speed setting means) for setting a target vehicle speed when starting constant speed traveling control, and an atmospheric pressure for detecting atmospheric pressure. The sensor 29 is equipped.

The outputs of these various sensors are input to an engine control circuit (hereinafter referred to as "ECU") 30. The ECU 30 is mainly composed of a microcomputer, and executes each engine control program stored in a built-in ROM (storage medium),
The fuel injection amount (air-fuel ratio) of the fuel injection valve 20 is controlled, and the ignition timing of the spark plug 26 is controlled.

Further, the ECU 30 executes the programs shown in FIGS. 3 to 9 to be described later when the driver sets the target vehicle speed with the cruise control switch 28 during traveling, so that the actual vehicle detected by the vehicle speed sensor 27. The throttle opening is automatically controlled so that the speed matches the target vehicle speed, and constant speed running control is performed to run the vehicle at the target vehicle speed.

The specific contents of the constant speed traveling control of this embodiment (1) will be described below. FIG. 2 is a block diagram showing the function of constant speed traveling control by the ECU 30. ECU30
The function of constant speed traveling control by means of the basic control amount calculation means 3
2, load correction amount calculation means 33, load correction regulation means 40,
It comprises a final control amount calculation means 34 and a vehicle drive source control means (not shown). Here, the basic control amount calculating means 32 calculates the basic control amount (P term, I term) by PI control, and the cruise control switch 28.
A vehicle speed deviation calculating means 35 for calculating a deviation between the target vehicle speed set in step 1 and the actual vehicle speed detected by the vehicle speed sensor 27;
P term calculation means 36 for calculating the basic control amount of the P term of control
And an I term calculation means 37 for calculating the basic control amount of the I term.

The load correction amount calculation means 33 determines P according to the intake pipe pressure (running load) detected by the intake pipe pressure sensor 18.
The load correction amount for correcting the basic control amounts of the terms I and I is calculated, and the P term load correction amount calculation means 38 for calculating the P term load correction amount and the I term load correction amount are calculated. It is composed of an I term load correction amount calculation means 39 for calculating.

The load correction regulation means 40 changes (corrects) the load correction amount for the I term according to the engine operating condition, for example, the pressure difference between the atmospheric pressure and the intake pipe pressure. In a region in which the pressure difference between and is equal to or less than the predetermined value A (engine output saturation region), the load correction change coefficient for changing the load correction amount for I term is set to the minimum value (for example, 0) to obtain the load correction amount for I term. Is a minimum value (for example, 0). Further, in a region where the pressure difference between the atmospheric pressure and the intake pipe pressure is equal to or greater than the predetermined value B (a region where the engine output increases substantially linearly as the throttle opening increases), the load correction change coefficient is set to the maximum value (for example, 1). )
By doing so, the I term load correction amount calculated by the I term load correction amount calculation means 39 is used without being changed. Further, in a region where the pressure difference between the atmospheric pressure and the intake pipe pressure is from the predetermined value A to B, the load correction change coefficient is increased as the pressure difference between the atmospheric pressure and the intake pipe pressure increases.

The final control amount calculation means 34 calculates the final required throttle opening (final control amount) by the following equation based on the basic control amounts of the P and I terms, the load correction amount, and the load correction change coefficient. Calculate Required throttle opening = P term basic control amount × P term load correction amount + I term basic control amount × I term load correction amount × load correction change coefficient

The ECU 30 controls the drive motor 31 of the throttle valve 15 so that the actual throttle opening detected by the throttle opening sensor 16 matches the requested throttle opening every time the required throttle opening is calculated by the above equation. The vehicle is driven at a constant speed at the target vehicle speed by feedback controlling the amount. This function corresponds to the vehicle drive source control means in the claims.

The constant speed traveling control of the present embodiment (1) described above is executed by the programs of FIGS. 3 to 9. The processing contents of each of these programs will be described below.

The vehicle speed deviation calculating program shown in FIG. 3 is a program for realizing the function of the vehicle speed deviation calculating means 35, and is repeatedly executed at a predetermined cycle during engine operation. When this program is started, first, in step 101, it is determined whether or not the constant speed traveling control is being performed. If the constant speed traveling control is not being performed, this program is terminated without performing the subsequent processing.

On the other hand, when the constant speed traveling control is being performed, the routine proceeds from step 101 to step 102, where the target vehicle speed v set by the cruise control switch 28 is set.
deviation dv between t and the actual vehicle speed vr detected by the vehicle speed sensor 27
To calculate. dv = vt-vr

After that, the routine proceeds to step 103, where the vehicle speed deviation dv calculated at step 102 is smoothed,
A vehicle speed deviation smoothed value dvsm (i) is obtained. dvsm (i) = dv- (dv-dvsm (i-1)) x α where dvsm (i-1) is the previous vehicle speed deviation smoothing value, α
This is the coefficient of anneal. This smoothing process is performed by the vehicle speed sensor 2
This is performed in order to reduce the influence of noise and the like superimposed on the output of 7.

The P term calculation program of FIG. 4 is a program that realizes the function of the P term calculation means 36, and is repeatedly executed at a predetermined cycle during engine operation. When this program is started, first in step 111, it is determined whether or not the constant speed traveling control is being performed. If the constant speed traveling control is not being performed, the routine proceeds to step 112, and the P term basic control amount tpb is set to 0. Set and exit this program.

On the other hand, when the constant speed traveling control is being performed, the routine proceeds from step 111 to step 113, and the P term basic control amount tpb is calculated by a table or a mathematical expression according to the vehicle speed deviation smoothed value dvsm (i). Then, this program ends.

The I term calculation program of FIG. 5 is a program for realizing the function of the I term calculation means 37, and is repeatedly executed at a predetermined cycle during engine operation. When this program is started, first in step 121, it is determined whether or not the constant speed traveling control is being performed. If it is not in the constant speed traveling control, the routine proceeds to step 122, and the integral amount tint is set to 0. , This program ends.

On the other hand, when the constant speed traveling control is being executed, the routine proceeds from step 121 to step 123, where the integral amount tint to be added to the previous I term basic control amount tib (i-1).
Is calculated by a table or a mathematical expression according to the vehicle speed deviation smoothed value dvsm (i). After that, the routine proceeds to step 124, where the current integrated amount tint is added to the previous I-term basic control amount tib (i-1) to obtain the current I-term basic control amount tib (i).
And end this program. tib (i) = tib (i-1) + tint

The P term load correction amount calculation program of FIG. 6 is a program for realizing the function of the P term load correction amount calculation means 38, and is repeatedly executed at a predetermined cycle during engine operation. When this program is started, first in step 131, it is determined whether or not the constant speed traveling control is being performed. If not, the processing proceeds to step 132, and the P term load correction amount Kp is set to 0. Set to and exit this program.

On the other hand, when the constant speed running control is being performed, the routine proceeds from step 131 to step 133, where the load correction amount Kp for P term is detected in the table or in accordance with the intake pipe pressure pm detected by the intake pipe pressure sensor 18. Calculated by a mathematical formula,
This program ends.

The I term load correction amount calculation program of FIG. 7 is a program for realizing the function of the I term load correction amount calculation means 39, and is repeatedly executed at a predetermined cycle during engine operation. When this program is started, first, in step 141, it is determined whether or not the constant speed traveling control is being performed. If it is not in the constant speed traveling control, the routine proceeds to step 142, and the I term load correction amount Ki is set to 0. Set to and exit this program.

On the other hand, when the constant speed running control is being performed, the routine proceeds from step 141 to step 143, where the table I or the load correction amount Ki for I term is detected according to the intake pipe pressure pm detected by the intake pipe pressure sensor 18. Calculated by a mathematical formula,
This program ends.

The load correction change coefficient calculation program shown in FIG. 8 is a program for realizing the function of the load correction regulation means 40, and is repeatedly executed at a predetermined cycle during engine operation. When this program is started, first step 151
Then, it is determined whether or not the constant speed traveling control is being executed. If the constant speed traveling control is not being executed, the routine proceeds to step 152, the load correction change coefficient Kh is set to 0, and this program ends.

On the other hand, when the constant speed running control is being performed, the routine proceeds from step 151 to step 153, where the load correction change coefficient Kh is determined according to the pressure difference (pa-pm) between the atmospheric pressure pa and the intake pipe pressure pm. Is calculated by a table or a mathematical formula. At this time, in a region where the differential pressure (pa-pm) is equal to or lower than the predetermined value A (engine output saturation region), the load correction change coefficient Kh
Is set to the minimum value (for example, 0), and the I term load correction amount Ki is set to the minimum value (for example, 0). In addition, the differential pressure (pa-
In a region where pm) is greater than or equal to a predetermined value B (a region in which the engine output increases almost linearly as the throttle opening increases), the load correction change coefficient Kh is set to the maximum value (for example, 1) so that The load correction amount Ki is used without change. In the region where the differential pressure (pa-pm) is from the predetermined value A to B, the load correction change coefficient Ki is increased as the differential pressure (pa-pm) increases.

The required throttle opening degree calculation program shown in FIG. 9 is a program for realizing the function of the final control amount calculation means 34, and is repeatedly executed at a predetermined cycle during engine operation. When this program is started, first step 16
At 1, it is determined whether or not the constant speed traveling control is being performed. If the constant speed traveling control is not being performed, the routine proceeds to step 162, where the required throttle opening t of the constant speed traveling control is set to 0, and the program To finish.

On the other hand, when the constant speed traveling control is being performed, the routine proceeds from step 161 to step 163, and the P term basic control amount tpb, the P term load correction amount Kp, and the I term basic control calculated by the respective programs are performed. Using the amount tib, the I term load correction amount Ki, and the load correction change coefficient Kh, the required throttle opening degree t for constant speed traveling control is calculated by the following equation. t = tpb × Kp + tib × Ki × Kh

During constant speed running control, every time the required throttle opening t is calculated in step 163 of the required throttle opening calculation program of FIG. 9, the actual throttle opening detected by the throttle opening sensor 16 is changed to the required throttle opening. By feedback-controlling the control amount of the drive motor 31 of the throttle valve 15 so as to match the degree t, the vehicle is driven at a constant speed at the target vehicle speed.

The effect of the constant speed running control of the present embodiment (1) described above will be described with reference to the time chart of FIG. The time chart of FIG. 11 shows that the running road changes from the uphill to the downhill during the constant speed running control and the running load (running resistance)
Vehicle speed, intake pipe pressure, PI control I
An example of the behavior of the term is shown in comparison with the conventional constant speed traveling control.

In the conventional constant speed running control, if the deviation between the target vehicle speed and the actual vehicle speed does not decrease due to an uphill or the like during the constant speed running control, the engine output is increased even if the throttle opening is increased. As shown by the broken line in FIG. 11, PI
The I term of the control continues to increase and the throttle opening is controlled to be further opened. In such a situation, when the vehicle suddenly approaches a downhill, the throttle opening is too wide (I term is too large). It takes some time to close to an appropriate throttle opening, and during that time, an excessive engine output is generated on the downhill and the vehicle is accelerated, and the actual vehicle speed greatly exceeds the target vehicle speed. There was a drawback that the fluctuation was large.

On the other hand, in the present embodiment (1), the load correction change coefficient is calculated according to the pressure difference between the atmospheric pressure and the intake pipe pressure, and the load correction amount for the I term is calculated using this load correction change coefficient. Is changed (corrected). Therefore, at the time t1 when it is determined that the throttle opening is in the engine output saturation region during the constant speed traveling control, it is possible to suppress the increase of the I term of the PI control and open the throttle opening unnecessarily. It is possible to avoid a situation where the direction is continuously controlled.
As a result, when the vehicle is running at a constant speed in the engine output saturation region, PI
Since the I term of the control is not too large (the throttle opening is not opening too large), the throttle opening can be closed quickly to reduce the engine output, and the actual vehicle speed can be controlled near the target vehicle speed. As a result, it is possible to reduce the vehicle speed fluctuation during the constant speed running control and perform stable constant speed running.

[Embodiment (2)] In the embodiment (2) of the present invention, the program of FIGS.
The I term is calculated by a method different from that of the embodiment (1).

The I term calculation program of FIG. 12 is obtained by modifying only the processing of step 124 of the I term calculation program of FIG. 5 described in the embodiment (1), and the processing of the other steps is the same. is there. In the I term calculation program of FIG. 12, in steps 121 and 123, the integral amount tint is calculated by a table or a mathematical expression according to the vehicle speed deviation smoothed value dvsm (i) during constant speed traveling control, and then in step 1
24a, the previous I term control amount tib (i-1), integral amount tint, I term load correction amount Ki, load correction change coefficient K
Using h, the final I-term control amount tib (i)
Ask for. tib (i) = tib (i-1) + tint x Ki x Kh

Here, the I term load correction amount Ki is calculated by the I term load correction amount calculation program of FIG. 7 as in the case of the above embodiment (1). The load correction change coefficient Kh is calculated by the load correction change coefficient calculation program shown in FIG. 13 described later. In the present embodiment (2), the load correction of the I term is performed by multiplying the integral amount tint by the I term load correction amount Ki and the load correction change coefficient Kh.

The load correction change coefficient calculation program of FIG. 13 is obtained by adding two steps 151a and 151b after step 151 of the load correction change coefficient calculation program of FIG. 8 described in the embodiment (1). The processing of the other steps is the same. In the load correction change coefficient calculation program of FIG. 13, when it is determined in step 151 that the constant speed traveling control is being performed, the process proceeds to step 151a, and the differential pressure (pa-pm) between the atmospheric pressure pa and the intake pipe pressure pm is predetermined. It is judged whether or not it is larger than the value, and this differential pressure (pa-p
If m) is larger than the predetermined value, the routine proceeds to step 151b, where the intake pipe pressure change amount Δpm per calculation cycle, that is, the current intake pipe pressure pm (i) and the previous intake pipe pressure pm.
It is determined whether the difference [pm (i) -pm (i-1)] from (i-1) is larger than a predetermined value.

As a result, in the present embodiment (2), the engine output saturation region is based on the differential pressure (pa-pm) between the atmospheric pressure pa and the intake pipe pressure pm and the intake pipe pressure change amount Δpm per calculation cycle. Or not. For example, when the differential pressure (pa-pm) between the atmospheric pressure pa and the intake pipe pressure pm is less than or equal to a predetermined value and the intake pipe pressure change amount Δpm per calculation cycle is less than or equal to a predetermined value (two steps 151).
If both a and 151b are determined to be “No”, it is determined that the engine output is in the saturation region, and the step 152
Then, the load correction change coefficient Kh is set to 0, and this program ends.

On the other hand, when the differential pressure (pa-pm) between the atmospheric pressure pa and the intake pipe pressure pm is larger than a predetermined value (in the case of "Yes" in step 151a), or the intake pipe pressure change per calculation cycle. When the amount Δpm is larger than the predetermined value (“Yes” in step 151b), the process proceeds to step 153, and the load correction is changed according to the differential pressure (pa-pm) between the atmospheric pressure pa and the intake pipe pressure pm. The coefficient Kh is calculated by a table or a mathematical formula.

The required throttle opening degree calculation program of FIG. 14 is obtained by modifying only the processing of step 163 of the required throttle opening degree calculation program of FIG. 9 described in the embodiment (1), and of the other steps. The process is the same. In the requested throttle opening calculation program of FIG. 14, when it is determined in step 161 that the constant speed traveling control is being performed, the process proceeds to step 163a, and the P term basic control amount tpb,
Using the P term load correction amount Kp and the I term control amount tib, the required throttle opening t for constant speed traveling control is calculated by the following equation. t = tpb × Kp + tib

In this case, since the value of the I term control amount tib is load-corrected using the load correction change coefficient Kh in step 124a of the I term calculation program of FIG. 12, constant speed running control is being performed. In addition, when the throttle opening is in the engine output saturation region, it is possible to suppress the increase of the I term of the PI control, and it is possible to avoid the situation where the throttle opening is controlled to open unnecessarily. It is possible to obtain the same effect as in the above embodiment (1).

The present invention is based on the above-mentioned respective embodiments (1),
Not limited to (2), when the throttle opening is in the engine output saturation region, the increase of the I term basic control amount before load correction is prohibited or the I term basic correction amount is limited. May be. Alternatively, when the throttle opening is in the engine output saturation region, the required throttle opening t
The increase of (final control amount) may be prohibited or the required throttle opening t may be limited.

In each of the above embodiments (1) and (2), the pressure difference (pa-p) between the atmospheric pressure pa and the intake pipe pressure pm.
m), the load correction change coefficient Kh is continuously changed. However, in a region where the differential pressure (pa-pm) is larger than a predetermined value, the load correction change coefficient Kh is set to 1 and the differential pressure (p
a-pm) is a predetermined value or less, the load correction change coefficient K
You may make h be 0. In this case, the control is simply to switch permission / prohibition of the load correction according to the pressure difference (pa-pm) between the atmospheric pressure pa and the intake pipe pressure pm.

Alternatively, paying attention to the change characteristic of the throttle opening and the intake pipe pressure shown in FIG. 10, the load correction is permitted or prohibited depending on the change rate of the intake pipe pressure with respect to the change of the throttle opening, or the load correction is performed. The correction amount may be changed. Even in this case, it is possible to obtain the same effect as in the case where the load correction is controlled using the differential pressure between the atmospheric pressure and the intake pipe pressure.

In each of the above embodiments (1) and (2), the intake pipe pressure detected by the intake pipe pressure sensor 18 is used as the traveling load information, but the intake air detected by the air flow meter 14 is used. The quantity may be used, or the engine rotation speed detected by the rotation speed sensor 25 may be used.

In each of the embodiments (1) and (2), the vehicle drive source is the engine 11 (internal combustion engine).
It may be applied to a vehicle that uses an electric motor or the like other than the engine as a drive source, and, of course, may be applied to a hybrid vehicle that uses both the engine and a drive source (electric motor or the like) other than the engine.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an entire engine control system showing an embodiment (1) of the present invention.

FIG. 2 is a block diagram schematically showing a function of constant speed traveling control by the ECU of the embodiment (1).

FIG. 3 is a flowchart showing a processing flow of a vehicle speed deviation calculation program according to the embodiment (1).

FIG. 4 is a flowchart showing a processing flow of a P term calculation program according to the embodiment (1).

FIG. 5 is a flowchart showing a processing flow of an I term calculation program according to the embodiment (1).

FIG. 6 is a flowchart showing a processing flow of a P item load correction amount calculation program according to the embodiment (1).

FIG. 7 is a flowchart showing a processing flow of a load correction amount calculation program for I terms of the embodiment (1).

FIG. 8 is a flowchart showing a processing flow of a load correction change coefficient calculation program according to the embodiment (1).

FIG. 9 is a flowchart showing a processing flow of a required throttle opening degree calculation program according to the embodiment (1).

FIG. 10 is a diagram for explaining the relationship between throttle opening, engine output, and intake pipe pressure.

FIG. 11 is a time chart showing an example of constant speed traveling control according to the embodiment (1).

FIG. 12 is a flowchart showing a processing flow of an I term calculation program according to the embodiment (2).

FIG. 13 is a flowchart showing a processing flow of a load correction change coefficient calculation program according to the embodiment (2).

FIG. 14 is a flowchart showing a processing flow of a required throttle opening degree calculation program according to the embodiment (2).

[Description of Reference Signs] 11 ... Engine (internal combustion engine), 12 ... Intake pipe, 14 ... Air flow meter, 15 ... Throttle valve, 16 ... Throttle opening sensor, 18 ... Intake pipe pressure sensor (running load detection means), 20 ... Fuel injection valve, 21 ... Exhaust pipe, 22 ...
Catalyst 25, rotational speed sensor 27, vehicle speed sensor (vehicle speed detecting means) 28, cruise control switch (target vehicle speed setting means) 29, atmospheric pressure sensor 30, 30 ECU
(Basic control amount calculation means, load correction amount calculation means, load correction regulation means, vehicle drive source control means), 31 ... Motor, 32
... Basic control amount calculation means, 33 ... Load correction amount calculation means, 3
4 ... Final control amount calculation means, 35 ... Vehicle speed deviation calculation means, 3
6 ... P term calculation means, 37 ... I term calculation means, 38 ... P term load correction amount calculation means, 39 ... I term load correction amount calculation means, 40 ... Load correction regulation means.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 45/00 364 F02D 45/00 364D F term (reference) 3D044 AA01 AA41 AC03 AC08 AC26 AC63 AD04 AE22 3G065 CA20 DA04 FA05 FA11 GA01 GA11 GA26 GA41 KA36 3G084 BA05 CA00 EB13 FA01 FA05 FA10 FA11 3G093 BA23 CB10 DA03 DA06 DB00 DB05 DB08 DB18 EA09 EC02 FA05 FB05 3G301 JA03 KB02 LA03 LB02 MA11 NA08 ND05 PA07Z PA09Z PA11A PA11Z03

Claims (6)

[Claims] 1. A target vehicle speed setting means for setting a target vehicle speed and a vehicle speed detecting means for detecting an actual vehicle speed, wherein the actual vehicle speed detected by the vehicle speed detecting means during constant speed traveling control is set by the target vehicle speed setting means. In a vehicle constant speed traveling control device for controlling a throttle opening of an internal combustion engine so as to match a set target vehicle speed, a vehicle load detecting means for detecting a vehicle traveling load, and the target vehicle speed during the constant vehicle speed control. A basic control amount calculating means for calculating a basic control amount for controlling the throttle opening according to a deviation from the actual vehicle speed, and a running load detected by the running load detecting means during constant speed running control. Load correction amount calculation means for calculating a load correction amount for correcting the basic control amount, and correction of the basic control amount by the load correction amount according to the operating condition of the internal combustion engine during constant speed traveling control (hereinafter " Load correction "
Based on the basic control amount and the load correction amount permitted or changed by the load correction regulating unit during constant speed traveling control. A final control amount calculation means for calculating a final control amount of the throttle opening, and a throttle opening control means for controlling the throttle opening based on the final control amount during constant speed traveling control. A constant speed traveling control device for a vehicle. 2. The load correction regulation means permits or prohibits the load correction or changes the load correction amount according to the pressure difference between the intake pipe pressure and the atmospheric pressure. Constant speed running control device for the vehicle. 3. The load correction regulation means permits or prohibits the load correction or changes the load correction amount according to the rate of change of the intake pipe pressure with respect to the change of the throttle opening. 1. The constant speed traveling control device for a vehicle according to 1. 4. The basic control amount calculation means calculates the basic control amount by PI control, and the load correction regulation means permits the load correction of item I of PI control according to the operating condition of the internal combustion engine. Ban or I
4. The constant speed running control device for a vehicle according to claim 1, wherein the load correction amount of the above item is changed. 5. A target vehicle speed setting means for setting a target vehicle speed and a vehicle speed detecting means for detecting an actual vehicle speed, wherein the actual vehicle speed detected by the vehicle speed detecting means during constant speed traveling control is set by the target vehicle speed setting means. In a vehicle constant speed traveling control device for controlling a throttle opening of an internal combustion engine so as to match a set target vehicle speed, a vehicle load detecting means for detecting a vehicle traveling load, and the target vehicle speed during the constant vehicle speed control. A basic control amount calculating means for calculating a basic control amount for controlling the throttle opening according to a deviation from the actual vehicle speed, and a running load detected by the running load detecting means during constant speed running control. Load correction amount calculation means for calculating a load correction amount for correcting the basic control amount, and permitting or prohibiting the increase of the basic control amount according to the operating condition of the internal combustion engine during constant speed traveling control, or Basis A basic control amount regulation unit that changes the correction amount; and a final control amount of the throttle opening based on the basic control amount regulated by the basic control amount regulation unit and the load compensation amount during constant speed traveling control. A constant speed traveling control of a vehicle, comprising: a final control amount calculating means for calculating; and a throttle opening control means for controlling the throttle opening based on the final control amount during constant speed traveling control. apparatus. 6. A target vehicle speed setting means for setting a target vehicle speed and a vehicle speed detecting means for detecting an actual vehicle speed, wherein the actual vehicle speed detected by the vehicle speed detecting means during constant speed traveling control is set by the target vehicle speed setting means. In a vehicle constant speed traveling control device for controlling a throttle opening of an internal combustion engine so as to match a set target vehicle speed, a vehicle load detecting means for detecting a vehicle traveling load, and the target vehicle speed during the constant vehicle speed control. A basic control amount calculating means for calculating a basic control amount for controlling the throttle opening according to a deviation from the actual vehicle speed, and a running load detected by the running load detecting means during constant speed running control. Load correction amount calculation means for calculating a load correction amount for correcting the basic control amount, and a final control amount of the throttle opening based on the basic control amount and the load correction amount during constant speed traveling control. To A final control amount calculating means for calculating, a final control amount restricting means for permitting or prohibiting the increase of the final control amount or changing the final correction amount according to the operating condition of the internal combustion engine during constant speed traveling control, A constant speed traveling control of a vehicle, comprising: a throttle opening control means for controlling the throttle opening based on the final control amount regulated by the final control amount regulating means during high speed traveling control. apparatus.