JPH07102787B2 - Vehicle running control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a travel control device having good response and less overshoot.

(Prior Art) In a vehicle having an automatic transmission, a vehicle speed or acceleration as a target traveling state amount is set based on the amount of depression of an accelerator pedal, and the intake air of an engine is set so as to reach the target acceleration or the like. A system has been developed that electronically controls the throttle valve (or the fuel injection amount control governor of a diesel vehicle) installed in the passage, and it is possible to set a target vehicle speed manually instead of the accelerator pedal depression amount. Speed control is known. In such a conventional device, feedback control is performed by comparing the target acceleration or the like with the actually measured acceleration or the like.

By the way, the acceleration of the traveling vehicle is proportional to the allowance torque, and the larger the allowance torque, that is, the torque value obtained by subtracting the running resistance torque from the output shaft torque, the better the acceleration response. However, if this margin torque is always set to a large value, that is, if the coefficient of the feedback gain is set to a large value, hunting and overshoot due to the control delay of the vehicle are likely to occur. Therefore, it is effective to adjust the margin torque according to the amount of environmental change applied to the traveling vehicle.

(Problems to be Solved by the Invention) As the environmental change amount applied to the traveling vehicle, there are respective change amounts of rolling resistance, air resistance, and acceleration resistance based on changes in road surface change, traveling wind pressure change, and throttle depression amount. For this reason,
Convert these into torque values, obtain as environmental impact torque, and calculate the target torque from this and the current output shaft torque,
If the throttle valve opening corresponding to the target torque is determined, the acceleration characteristic or the vehicle speed characteristic which is always optimal for the environmental change, that is, the responsiveness is good and the overshoot or the like is suppressed can be obtained. However, these characteristics will cause deterioration of responsiveness and increase of overshoot, and controllability will deteriorate unless the current weight of the vehicle is accurately obtained.

The object of the present invention is to always respond well to changes in weight,
It is an object of the present invention to provide a vehicle travel control device with less overshoot.

(Means for Solving Problems) In order to achieve the above-mentioned object, the present invention, as shown in FIG. 2, includes a traveling state calculating means 1 for calculating a target traveling state amount of a vehicle based on an accelerator pedal depression amount. A current output shaft torque based on an environmental impact torque calculating means 2 for calculating an environmental impact torque based on the difference between the target traveling state quantity and the current traveling state quantity and the vehicle weight, and the engine speed of the vehicle and engine load information. Current output shaft torque calculation means 3 for calculating
Target throttle opening calculation means 4 for calculating the target throttle opening based on the target torque calculated from the current output shaft torque and the environmental influence torque, and the throttle opening by the difference between the target throttle opening and the current throttle opening. A throttle valve drive control means 6 for outputting an output for adjusting the above to the throttle valve drive means 5, and a vehicle weight calculation means 8 for calculating the weight of the vehicle based on the air pressure value of an air suspension 7 mounted on this vehicle. Take the configuration you had.

(Operation) The vehicle weight calculation means calculates the total weight of the vehicle based on the air pressure value of the air suspension of the vehicle, and the throttle valve drive control means sets the throttle opening calculated based on the total weight via the throttle valve drive means. The throttle valve can be adjusted.

(Embodiment) The vehicle running control device shown in FIG. 1 supplies fuel by an electronic fuel injection device (ECI), and shifts and outputs the rotation of an engine output shaft by an electronically controlled automatic transmission (ECL). It is mounted on the engine 11. This vehicle traveling control device is a so-called wire drive (DB drive) that opens and closes the throttle valve 24 by the step motor 23.
W) method is adopted. The travel control device detects the depression amount X of the accelerator pedal 12 with an accelerator position sensor (hereinafter simply referred to as an APS sensor) 13, detects shift speed information with a select switch 14, and controls an electronically controlled suspension (hereinafter simply referred to as ECS). Vehicle height information and spring constant switching information are detected from the ECS computer 15 which is the control means, and the air pressure in the air chamber 16 (see FIG. 3) of the ECS is set to the front (P
F) and rear (PR) side PF pressure sensor 17 and PR pressure sensor 18 respectively detect, brake on by side brake switch 19, side brake on by side brake switch 20 and door open by door switch 21.
To detect each. Further, based on these input signals, the motor control computer 22 detects the throttle opening θ by the APS sensor 48, calculates the motor drive amount ΔD for adjusting this to the target value, and outputs the output signal to the step motor 23. To do. Further, the step motor 23 is driven by ΔD to adjust the throttle valve 24 in the intake passage 25 to the required throttle opening θ.

A fuel injection device (ECI) has an injector 26 attached to an intake passage 25 of the engine 11, and the injector 26 is controlled to be opened and closed by an ECI computer 27 as a fuel injection amount control means. ECI computer 27 has O ₂ sensor 28, water temperature sensor 29, atmospheric pressure sensor 30, vehicle speed sensor 31, engine speed sensor
32, the detection signal is input from other sources. Based on these input signals, the ECI computer 27 determines the fuel injection amount, fuel injection timing, etc., and drives and controls the injector 26.

Electronically controlled automatic transmission (ECL)
Is equipped with an ECL computer 34 for controlling the automatic transmission 33 to be switched to the optimum shift speed, which calculates the optimum shift speed based on the shift speed information of the select switch 14 and the running state information from the motor control computer 22.

As shown in FIG. 3, the ECS has a vehicle height adjustment function and a spring constant switching function. That is, the spring constant switching function is performed by the air chambers 16 of the two left and right front strut units 35 and the two left and right rear shock absorber units 36.
This is accomplished by connecting and disconnecting the sub tank 37 on the upper side and the sub tank 37 by the two hard / soft air valves 38 and the switching means 381. Vehicle height adjustment function for each front and rear air chamber
Change the pressure value of 16, low (PL) position, high (PH) position,
This is accomplished by selecting a special high position (not shown).

In this case, the ECS computer 15 detects with the pressure switch 43 whether or not the air has been supplied from the compressor 42 to the reserve tank 41 and has reached the specified value, and the air with the specified pressure is supplied to the intake valve 44, the front vehicle height air valve 39, and the rear vehicle height air valve 39. It is supplied to and exhausted from each air chamber 16 (only one is shown) via a vehicle height air valve 40. Then, based on the detection signals of the front and rear vehicle height sensors 45, 46, the vehicle height is controlled so as to reach the specified position.

The PF is connected to the pipe 47 communicating with each air chamber 16 as described above.
A pressure sensor 17 and a PR pressure sensor 18 are attached.

As shown in FIG. 2, the acceleration control process of the vehicle travel control device is performed by a traveling state amount calculation means, an environmental influence amount torque calculation means, a current output shaft torque calculation means, a target stoll opening degree calculation means, and a throttle. It is performed by a motor control computer 22 having the functions of valve drive control means and vehicle weight calculation means. The control processing sequence built in the ROM of the computer will be described below with reference to the flowcharts shown in FIGS. 5, 6 and 7.

When the power of the motor control computer 22 is turned on, the circuit failure of each input signal, determination of whether each signal value is at the reference level, initialization of memory clear processing, etc. is performed, and the vehicle weight is reduced to w ₀ = Temporary set value of vehicle weight to be (vehicle weight + 65Kg) is taken in. Next, waiting for the engine to turn on, when it turns on, it is determined whether or not the vehicle speed is zero. When the engine speed is zero, the vehicle weight detection process starts, and when the vehicle starts running, the throttle valve drive process starts.

Next, in the throttle valve drive routine, first, the engine speed N, the accelerator pedal depression amount X, the throttle valve opening degree θ, and the shift speed information are detected via the sensors 32, 13, 48 and 14. Then, while the power transmission state is not entered, the process proceeds to step a3,
The throttle opening θ is obtained by multiplying the accelerator depression amount X by a constant a, the step motor 23 is driven so as to reach the throttle opening θ, and the process returns.

When it is determined that the power transmission state is entered in step a2, the process proceeds to step a5, and the target acceleration DVS is calculated from the accelerator depression amount X.
To calculate. Next, based on the vehicle speed, this is differentiated to calculate and read the actual acceleration DVA. Note that a G sensor (not shown) may be used for the same process.

At step a7, the current throttle opening θ and engine speed N
The current output torque TEM is calculated from. Note that the intake air amount A / N, intake manifold negative pressure, or the like may be used instead of the throttle opening θ. Next, in step a8, the target torque value TOM is calculated according to the following equation.

TOM = w · r / g × K ₁ × (DVS-DVA) + TEM Note that K ₁ is a coefficient that takes into account the inertia of the engine, transmission, tires, etc.

When step a9 is reached, the target throttle opening θ _S is determined based on the target torque TOM and the engine speed N according to the gear stage. Then, the obtained target throttle opening θ
The difference ΔD between _S and the current throttle opening θ is obtained as the step motor drive amount, the step motor 23 is driven by this amount, the throttle valve 24 is adjusted to the target throttle opening θ _S , and the process returns.

In the vehicle weight detection routine, first, stop the vehicle to detect the vehicle speed.
It is detected by the output of 31 and if not stopped, the process proceeds to the throttle valve drive processing, and if stopped, the process proceeds to step b3. In step b3, it is determined whether or not the set time T (here, 5 to 10 seconds) has elapsed, and if NO, the process returns to step b1.
If YES, go to step b4. If the door is not closed by the door switch 21, the process proceeds to step b1. If the door is closed, the process proceeds to step b5. In step b5, the information on whether or not the vehicle height is being adjusted is received from the ECS computer 15.
If not adjusted, go to step b6. EC in step b6
The S computer 15 receives information as to whether the air suspension hardness is being adjusted, and proceeds to step b1 during adjustment and to step b6 during non-adjustment. In step b6, the ECS computer 15 receives information as to whether or not the hardness of the air suspension is being adjusted, and during adjustment, the process proceeds to step b1. When not adjusting, the process proceeds to step b7.

In step b7, whether the vehicle height is normal (low), high, or special high is received from the ECS computer as vehicle height information and judged, and if normal, the process proceeds to step b8. In either case of high and special high, the same control processing as that of steps b8 to b15 described later is performed, and the difference is that the set values P1 and P2 of step b10 and the weight calculation map used in step b13 ( 4 (a),
(See (b)) is only different in that it differs depending on the vehicle height, and therefore the description is omitted.

In step b8, it is determined whether the hardware is soft or soft based on the ECS spring constant information. In hardware, the processing for hardware (not shown) is performed, and in software, the processing proceeds to step b9. Here, the processing for hardware is defined values P1 and P2 in step b10 and the weight calculation map used in step b13 (FIG. 4 (a),
(See (b)) is different between hardware and software, so description will be omitted. When the hardware process ends, the process reaches step b14.

When step b9 is reached, the front and rear wheel side air suspension air pressures (PF), (PR) are detected based on the outputs of the PF pressure sensor 17 and the PR pressure sensor 18.

Then, the difference between the front and rear air pressures and the previous value is the specified value P1, P
If there is a difference of 2 or more, that is, if it is considered that a vehicle height change has occurred, the process proceeds to step b11, and the front and rear air values P
Clear F and PR and return to step b1. On the other hand, if it is determined that there is no change in vehicle height, the process proceeds to step b12, where N
The average value PFA, PRA is obtained by taking the front and rear air pressures PFi, PRi only once.
Ask for.

Thereafter, based on the averaged front and rear air pressures, a normal and software vehicle weight calculation map written in the memory in advance as shown in FIGS. 4 (a) and (b) is used. The front-rear loads WF and WR are calculated, and the process proceeds to step b14.

In step b14, the front and rear loads are added to calculate the vehicle weight WA,
This is replaced with the current vehicle weight W in the memory and the process returns.

The vehicle running control device described above determines the driver's intention to accelerate from the accelerator pedal depression amount X, accurately reads the change in the total weight of the current vehicle by the vehicle weight detection process using the air pressure of the suspension, and Acceleration operation can be performed with a required vehicle acceleration pattern that is determined according to the driver's intention to accelerate regardless of the change in weight. That is, the acceleration feeling according to the driver's intention to accelerate becomes independent of the change in the vehicle weight, and the acceleration controllability can be improved and the easy drive can be achieved.

Although the above-described vehicle travel control device has been described as an acceleration control device, the present invention can be applied as a vehicle speed control device instead of the acceleration control device.

(Effects of the Invention) According to the vehicle travel control device of the present invention, it is possible to read the weight change using the air pressure value of the air suspension and take the torque corresponding to the change into the target torque value. It is possible to perform so-called easy drive, which has good responsiveness to changes in speed and vehicle speed and has little overshoot.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a vehicle travel control device as an embodiment of the present invention, FIG. 2 is a block diagram of the same device, and FIG. 3 is a diagram for explaining a mounting state of a pressure sensor used in the same device, 4 (a) and 4 (b) are vehicle weight calculation maps incorporated in the computer in the same apparatus, and FIGS. 5, 6, and 7 are flowcharts showing the control processing of the computer in the same apparatus, respectively. There is. 1 ... Running state quantity calculation means, 2 ... Environmental impact torque calculation means, 3 ... Current output shaft torque calculation means, 4 ... Target throttle opening degree calculation means, 5 ... Throttle valve drive means, 6
...... Throttle valve drive control means, 7 ...... Air suspension, 8 ...... Vehicle weight calculation means, 11 ...... Engine, 15 ...... EC
S computer, 16 …… air chamber, 17 …… PF pressure sensor, 18 …… PR pressure sensor, 22 …… motor control computer.

Claims (1)

[Claims] 1. A running state quantity calculating means for calculating a target running state quantity of a vehicle based on an accelerator depression amount, and an environmental influence based on a difference between the target running state quantity and the current running state quantity and the weight of the vehicle. Environmental influence torque calculation means for calculating torque, current output shaft torque calculation means for calculating current output shaft torque from the engine speed of the vehicle and engine load information, and calculation from the current output shaft torque and the environmental influence torque A target throttle opening calculation means for calculating a target throttle opening based on the target torque, and a throttle for outputting to the throttle valve driving means an output for adjusting the throttle opening by a difference between the target throttle opening and the current throttle opening. Valve drive control means and weight calculation means for calculating the weight of the vehicle based on the air pressure value of the air suspension mounted on the vehicle The vehicle running control system having a.