JPH10122357A - Vehicle driving force control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control decelerating torque including engine braking force giving priority to the deceleration demand intention of a driver by maintaining a change gear ratio determined immediately before operation in the case of a brake being operated. SOLUTION: When a brake switch is off, the turbine rotating speed of a torque converter, the present speed change gear position of an automatic transmission 2, and the like are inputted, and the maximum value and minimum value of torque which an engine 1 can output at the present turbine rotating speed are retrieved from a map to compute maximum and minimum driving force that can be outputted in the present speed change gear position of the transmission 2. The maximum and minimum driving force is then compared with target travel resistance, and a shift correction is made to determine a speed change gear position. Target engine torque is then obtained so as to materialize target travel resistance at a gear ratio, and an intake throttle valve is driven so as to obtain target throttle valve opening correspoding to the target engine torque. When the brake switch is on, no correction is made so as to avoid control against a decelerating intention at the time of operating a brake pedal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a vehicle driving force control device for controlling the longitudinal movement of an automobile.

[0002]

2. Description of the Related Art Generally, in an automatic transmission mounted on a vehicle, a position of a transmission gear is determined by an accelerator pedal opening degree operated by a driver and a speed of the vehicle. During normal traveling, the lower the accelerator pedal opening, the higher the speed of the transmission gear, and the higher the speed of the vehicle, the higher the speed of the transmission gear.

[0003] Therefore, when the driver releases the accelerator pedal during downhill driving or the like, the accelerator pedal opening decreases, and the shift gear position is controlled to a high speed side, so that the engine brake of the vehicle is ineffective. It is also conceivable that the driver may give an extra feeling of acceleration or the frequency of operating the brakes will increase, and the brake material will be consumed more quickly.

To cope with this, as disclosed in Japanese Patent Application Laid-Open No. Hei 5-71634, it is determined that the vehicle is traveling on a downhill, and the transmission gear position of the automatic transmission is corrected to a lower speed. By doing so, the engine brake is activated positively.

[0005]

However, in such a conventional vehicle driving force control apparatus, when the vehicle is traveling on a downhill, the barrier breaker is automatically adjusted to a target acceleration resistance determined from the traveling resistance or the like. When correcting the transmission gear position to the low speed side,
Since the braking operation of the driver and the engine braking force are not particularly associated with each other and controlled, the deceleration torque intended by the driver cannot be obtained, which may give a sense of incongruity.
For example, even if the driver operates the brake to request further deceleration, the target acceleration resistance does not change, so that the position of the transmission gear does not change, contrary to the driver's intention to increase the deceleration force.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicle driving force control device that controls a vehicle deceleration torque including an engine braking force by giving priority to a driver's intention to request deceleration. Aim.

[0007]

According to a first aspect of the present invention, there is provided a vehicle driving force control apparatus for controlling a speed ratio of rotation transmitted from an engine to driving wheels according to a driving state of a vehicle. When the brake operation of the vehicle is performed, the gear ratio determined immediately before the brake operation is performed is maintained.

According to a second aspect of the present invention, there is provided a vehicle driving force control device.
According to the first aspect of the present invention, as shown in FIG. 5, a running resistance calculating means b for calculating a running resistance R of the vehicle, and a target acceleration according to the speed VSP of the vehicle when the accelerator pedal is at the fully closed position. Target acceleration resistance calculating means c for calculating the resistance Ra; target running resistance calculating means e for calculating the sum of the running resistance R and the target acceleration resistance Ra as the target running resistance Rt of the vehicle; Maximum driving force Fup and minimum driving force Fd that can be output at the gear position
surplus driving force calculation means a for calculating own surplus driving force
A shift correction determining means f for determining a shift gear position in accordance with a marginal driving force with respect to a target running resistance Rt of the vehicle, a shift correction means h for instructing the determined shift gear position, and a brake operation of the vehicle is performed. And a brake operation determining means i for maintaining the transmission gear position determined immediately before the brake operation is performed.

A vehicle driving force control device according to a third aspect of the present invention
In the invention according to claim 1 or 2, as shown in FIG. 6, running resistance calculating means b for calculating running resistance R of the vehicle.
A target acceleration resistance calculating means c for calculating a target acceleration resistance Ra according to the speed VSP of the vehicle when the accelerator pedal is in the fully closed position; and a target running resistance of the vehicle calculated by summing the running resistance R and the target acceleration resistance Ra. Target running resistance calculating means e for calculating the resistance Rt; and marginal driving force calculating means a for calculating a marginal driving force of a maximum driving force Fup and a minimum driving force Fdown that can be obtained at the current transmission gear position with respect to the target traveling resistance Rt. Shift correction determining means f for determining a shift gear position in accordance with a marginal driving force with respect to a target running resistance Rt of the vehicle.
Shift correcting means h for instructing the determined shift gear position.
And an engine output torque correcting means g for correcting the engine output torque so as to obtain the target running resistance Rt according to the shift gear position, and when the brake operation of the vehicle is performed, it is determined immediately before the brake operation is performed. Brake operation determining means i for maintaining the transmission gear position and the engine output torque
And.

[0010]

According to the first aspect of the present invention, when the driver depresses the brake pedal, the gear ratio is automatically maintained, and control against the driver's intention to decelerate is performed. Can be avoided. As a result, the driver can operate the brake with peace of mind, and it is possible to generate a really strong braking force.

In the vehicle driving force control device according to the present invention, when the driver does not depress the brake pedal, the position of the transmission gear is corrected and matched with the target acceleration resistance, and the proper engine braking is performed even when the vehicle is traveling on a downhill. Power is gained.

When the driver depresses the brake pedal, the position of the transmission gear is held at the value immediately before the brake operation, so that control against the driver's strong intention to decelerate can be avoided. As a result, the driver can operate the brake with peace of mind, and it is possible to generate a really strong braking force.

In the vehicle driving force control apparatus according to the third aspect, when the driver does not depress the brake pedal, the shift gear position and the engine output are corrected and controlled so as to match the target acceleration resistance, so that the gear position is suitable even during downhill running. High engine braking power.

When the driver depresses the brake pedal, the gear position and the engine output torque are
Since the value is maintained at the value immediately before the brake operation, it is possible to avoid performing control against the driver's strong intention to decelerate. As a result, the driver can operate the brake with peace of mind, and it is possible to generate a really strong braking force.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 1 is an engine mounted on a vehicle, 2 is an automatic transmission connected to an output shaft of the engine 1, and connected to an output shaft of the automatic transmission 2 to transmit power to driving wheels (not shown). Drive shaft.

The engine 1 includes an intake throttle valve interposed in an intake passage (not shown), an injector for supplying fuel to the intake passage, an ignition device for igniting a mixture in a cylinder, and the like. It is controlled by a signal output from the control unit 6.

The automatic transmission 2 has a reduction gear mechanism comprising four forward gears and one reverse gear.
The transmission gear position can be switched by a signal output to the transmission command valve 5 from the transmission.

The driving force control unit 72 includes a vehicle speed sensor 8 for detecting a running speed of the vehicle, a throttle opening sensor 9 for detecting a throttle valve opening, an engine rotation sensor 10 for detecting an engine speed, and an automatic transmission 2.
A turbine rotation sensor 11 for detecting the turbine rotation speed of the torque converter, a brake switch 12 for detecting whether or not a brake pedal is depressed, an AT input rotation sensor 13 for detecting the input rotation speed of the automatic transmission 2, Each detection signal of the vehicle acceleration sensor 14 for detecting acceleration is input, and a shift gear position signal is output in accordance with these driving conditions.

As shown in FIG. 2, the driving force control unit 7 includes a running resistance calculating means 21 for obtaining a running resistance R of the vehicle including a road surface gradient and an air resistance. A target acceleration resistance calculating means 22 for determining a predetermined target acceleration resistance Ra in accordance therewith; and a target running resistance calculation means 2 for giving the sum of the obtained running resistance R and the target acceleration resistance Ra as a target running resistance Rt of the vehicle.
3 is provided.

The surplus driving force calculating means 24 calculates the maximum driving force F that can be output at the current gear position of the automatic transmission 2.
Up and the minimum driving force Fdown are calculated, and a marginal driving force with respect to the driving force at the current transmission gear position is calculated.

The shift correction determining means 25 determines whether or not the shift gear position of the automatic transmission 2 should be corrected to a gear position one step lower in relation to the target running resistance Rt of the vehicle and the magnitude of the marginal driving force. .

The engine output torque correcting means 26, when the shift correction determining means 25 determines that the shift gear position of the automatic transmission 2 should be corrected to a lower gear position by one step, according to the corrected transmission / interruption ratio. In order to achieve the target running resistance Rt, the engine output torque is corrected, and the throttle valve opening, ignition timing, fuel injection amount, and the like are controlled via an output device 4 provided in the engine 1.

The gist of the present invention is as follows. When the brake switch 12 of the vehicle is turned on, the driving force control unit 7
The transmission gear position corrected immediately before 2 is turned on and the engine output torque corrected by the engine output torque correction means 26 are maintained.

The flowchart of FIG. 3 shows a routine for calculating the target running resistance Rt for executing the shift correction.
It is executed every 0 msec.

To explain this, first, step 1
01, the turbine speed Nt of the torque converter and
The vehicle speed VS is input.

Next, the routine proceeds to step 102, where the running resistance R of the vehicle is calculated. The running resistance R is calculated by the sum of the gradient resistance Rθ, the rolling resistance Rr, and the air resistance Rv.

Then, the program proceeds to a step 103, wherein a target acceleration resistance Ra when the intake throttle valve is fully closed is retrieved from the map 103M according to the magnitude of the vehicle speed and determined.

Then, the program proceeds to a step 104, wherein a final target running resistance Rt of the vehicle is calculated. Rt is the running resistance R
And the target acceleration resistance Ra.

The flowchart of FIG.
This shows a routine for calculating the transmission gear position and the opening degree of the intake throttle valve so as to obtain .gamma., And is executed in the driving force control unit 7, for example, every 10 msec.

First, at step 110, it is determined whether or not the brake switch is ON. When the brake switch is OFF, the routine proceeds to step 111, where the turbine speed Nt of the torque converter and the current speed of the automatic transmission 2 are determined. The transmission gear position CurZr and the like are input.

Then, the process proceeds to a step 112, wherein a maximum value xTt and a minimum value mTt of the engine torque that the engine 1 can output at the current turbine speed are searched from the map 112M.

Then, the process proceeds to a step 113, wherein the searched maximum and minimum output torque values xTt, mT of the engine 1 are determined.
Based on t, the maximum driving force Fup and the minimum driving force Fdown that can be output at the current gear position of the automatic transmission 2 are calculated by the following equations.

Fup = xTt × CuZr × Zdf / rwh (1) Fdown = mTt × CuZr × Zdf / rwh (2) where Zdf is the final reduction ratio, and rwh is the tire effective radius of the drive wheel.

Subsequently, the routine proceeds to step 114, where the target running resistance Rt, the maximum driving force Fup, and the minimum driving force Fdown are obtained.
And whether or not to perform the shift correction is determined.

When the maximum driving force Fup is larger than the target running resistance Rt, the routine proceeds to step 117, where an upshift for correcting the gear ratio to a lower gear ratio and a higher gear position is performed.

Further, the minimum driving force F is obtained from the target running resistance Rt.
If down is smaller, proceed to step 116,
A downshift is performed to correct the gear position to a lower gear position with a larger gear ratio.

The target running resistance Rt is equal to the maximum driving force Fu.
If it is between p and the minimum driving force Fdown, it is determined that there is no need for gear shift correction, and the routine proceeds to step 115.

Thus, at step 118, the next selected transmission gear position NxtZr is determined.

Then, the process proceeds to a step 119, wherein a target engine torque Tt is determined so that the target running resistance Rt is satisfied by the gear ratio NxtZr, and a target throttle of the engine 1 is obtained from the map 119M according to the current turbine speed Nt. The valve opening tTV0 is searched.

Finally, the routine proceeds to step 120, where the intake throttle valve is driven so that the determined target throttle valve opening tTVO is obtained.

On the other hand, when the brake switch is ON, the control for automatically correcting the target driving force in step 111 and thereafter is not performed, and the routine ends.

Thus, when the driver depresses the brake pedal, the shift gear position is not automatically corrected and controlled to match the target acceleration resistance, so that control against the driver's strong deceleration intention is performed. can avoid. As a result, the driver can operate the brake with peace of mind, and it is possible to generate a really strong braking force. Furthermore, the transmission gear position and the engine output torque are maintained at the values immediately before the brake operation, so the engine braking force does not change during the brake operation and automatically matches the target acceleration resistance when the brake pedal is released. So that there is no delay in shifting to downhill traveling control.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a driving force control unit.

FIG. 3 is a flowchart showing control contents.

FIG. 4 is a flowchart showing control contents.

FIG. 5 is a diagram corresponding to claims of the invention described in claim 2;

FIG. 6 is a diagram corresponding to claims of the invention according to claim 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Automatic transmission 3 Drive shaft 4 Output device 5 Shift command valve 6 Engine control unit 7 Driving force control unit 8 Vehicle speed sensor 9 Throttle opening sensor 10 Engine rotation sensor 11 Turbine rotation sensor 12 Brake switch 13 Transmission input rotation sensor 14 Vehicle acceleration sensor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16H 59:44 59:54

Claims (3)

[Claims] 1. A vehicle driving force control device for controlling a speed ratio of rotation transmitted from an engine to driving wheels in accordance with a driving state of a vehicle, wherein when a braking operation of the vehicle is performed, immediately before the braking operation is performed. A vehicle driving force control device characterized in that the determined gear ratio is maintained. A running resistance calculating means for calculating a running resistance R of the vehicle; and a speed VS of the vehicle when the accelerator pedal is at a fully closed position.
Target acceleration resistance calculating means for calculating the target acceleration resistance Ra in accordance with P; target running resistance calculation means for calculating the sum of the running resistance R and the target acceleration resistance Ra as the target running resistance Rt of the vehicle; The maximum driving force Fup and the minimum driving force Fdown that can be output at the current transmission gear position with respect to
Marginal driving force calculating means for calculating the marginal driving force of the vehicle, gear shift correction determining means for determining the gear position of the transmission in accordance with the marginal driving force for the target running resistance Rt of the vehicle, and gear shift correcting means for instructing the determined gear position The vehicle driving force according to claim 1, further comprising: a brake operation determining unit that maintains a shift gear position determined immediately before the brake operation is performed when the vehicle is operated by a brake. Control device. 3. A running resistance calculating means for calculating a running resistance R of the vehicle, and a speed VS of the vehicle when the accelerator pedal is at a fully closed position.
Target acceleration resistance calculating means for calculating the target acceleration resistance Ra in accordance with P; target running resistance calculation means for calculating the sum of the running resistance R and the target acceleration resistance Ra as the target running resistance Rt of the vehicle; The maximum driving force Fup and the minimum driving force Fdown that can be output at the current transmission gear position with respect to
Marginal driving force calculating means for calculating the marginal driving force of the vehicle, gear shift correction determining means for determining the gear position of the transmission in accordance with the marginal driving force for the target running resistance Rt of the vehicle, and gear shift correcting means for instructing the determined gear position An engine output torque correcting means for correcting the engine output torque so as to obtain the target running resistance Rt according to the position of the transmission gear; and a shift determined immediately before the brake operation is performed when the vehicle is operated. The vehicle driving force control device according to claim 1, further comprising: a brake operation determining unit that maintains a gear position and an engine output torque. 4.