Honda Giken Kogyo Kabushiki Kaisha

Toru Ikeda

Shuji Shiraishi

Takashi Nishihara

Osamu Yano

Osamu Yamamoto

Fumiaki Honjyo

Hironobu Kiryu

Shigenobu Sekiya

Ryoji Mori

Naoki Omomo

In a traction control system, an initial engine torque for a traction control is selected from the following engine torques: an engine torque calculated from a throttle opening degree and an engine revolution-number; a required engine torque calculated from a total acceleration and a vehicle speed; and an engine torque corresponding to a road surface of an extremely low friction coefficient, depending upon a slipping state determined by comparing a driven wheel speed with slip reference values. When the driven wheel speed repeatedly exceeds the slip reference value, it is determined that a hunting has been generated, and the engine torque corresponding to the road surface of the extremely low friction coefficient is selected, and the engine torque is largely reduced. Thus, when the friction coefficient of the road surface is low, the driven wheel speed is prevented from hunting.

Traction control system for vehicle

When a steady straight advancing state presuming device presumes that the vehicle is in a steady straight advancing state, and a slip rate calculating device calculates a small slip rate, based on an output from a driving-state detecting device, or when the steady straight advancing state presuming device presumes that the vehicle is in the steady straight advancing state, and a driven wheel torque calculating device calculates a small driven wheel torque, based on the output from the driving-state detecting device, a correction execution determining device determines that the vehicle is in a stable state suitable for correcting the wheel speed. By a command from the correction execution determining device, a correcting device corrects the driven wheel speed or the follower wheel speed based on a speed ratio of the driven wheel speed to the follower wheel speed calculated by a speed ratio calculating device. Thus, when a different-diameter tire has been mounted on a wheel, it is possible to precisely correct the wheel speed without being influenced by the slipping of the driven wheels or by the turning of the vehicle.

Wheel speed correcting system

The rotational speed difference between rotational speeds of front and rear road wheels of a motor vehicle is weighted by a first ratio, and the difference between the rotational speed difference between rotational speeds of front left and right road wheels and an average signal of reference steering angle or between the rotational speed difference between rotational speeds of rear left and right road wheels and the average signal of reference steering angle is weighted by a second ratio. A sum signal representative of the sum of the rotational speed difference weighted by the first ratio and the difference weighted by the second ratio is used to determine a pneumatic tire pressure reduction highly accurately even when running conditions of the motor vehicle change such as when the motor vehicle makes a turn.

System for determining pneumatic tire pressure for motor vehicle

A method for determining the fully-closed state of a subsidiary throttle valve. If a stable state judging circuit judges that there is no outside influence exerted on the operational state of the engine (a state in which the vehicle is stopped and the engine is in an idling state) even if the subsidiary throttle valve is fully closed, a valve closing circuit closes the subsidiary throttle valve and a fully-closed state determination is carried out. If the opening degree of the subsidiary throttle valve or the engine revolution number is largely varied during the determination process of the fully-closed state determination circuit, a valve-closing inhibiting circuit inhibits the closing of the subsidiary throttle valve to discontinue the determination. Even if all of the conditions for determination are satisfied again, the closing of the subsidiary throttle valve and the restarting of determination by the fully-closed state determination circuit are inhibited until the comparator circuit judges that the vehicle starts traveling and vehicle speed exceeds a reference value.

System for determining the fully-closed state of subsidiary throttle

A subtractor calculates an actual wheel speed difference between rotational speeds of left and right wheels on a motor vehicle, and a steering angle converter calculates an actual steering angle from the actual wheel speed difference. The difference between the actual steering angle and an adequate steering angle which is produced based on a lateral acceleration is compared with a predetermined reference range. If the difference between the actual and adequate steering angles exceeds the predetermined reference range, then the pneumatic pressure of a tire on one of the left and right wheels is determined as being lowered. In the steering angle converter, a weight value is established according to a running condition of the motor vehicle, and the calculated actual steering angle or comparative sensitivity is varied according to the weight value. Since the comparative sensitivity is varied according to the running condition, a reduction in the pneumatic pressure of the tire can be detected even under running conditions which lead to large errors.

Pneumatic tire pressure change detecting system comparing wheel speeds

A driven wheel torque control system includes a slip-reduction output torque control device for adjusting the output torque from a prime mover of a vehicle in accordance with the slipping state of a driven wheel driven by the prime mover in order to reduce an excessive slipping of the driven wheel, an operation quantity detecting device for detecting the operation quantity of an operating element for adjusting the output torque from the prime mover, a grip force detecting device for detecting a grip force of a road surface, an output torque gain changing device for changing the output torque control gain from the prime mover with respect to the output from the operation quantity detecting device on the basis of the output from the grip force detecting device, and a gain variable output torque control device for adjusting the output torque from the prime mover on the basis of the output torque control gain changed by the output control gain changing device. Thus, it is possible to positively control the slipping state of the driven wheel on the basis of a driver's will.

Driven wheel torque control system

In a traction control device in which an initial control torque of an engine is determined in accordance with an acceleration of the vehicle, when an excessive slipping of driven wheels is detected, a time taken for proceeding of the excessive slipping of the driven wheels from a large slip state to a small slip state is counted by a timer. If such time is smaller than a reference time and a gear ratio of the vehicle is of a first gear shift to provide a low vehicle speed, it is decided that the vehicle is traveling on an upward sloping road, and a lower limit value for defining the initial control torque of the engine determined in an initial control torque calculating means is corrected into an increased value in an initial torque correcting means. This prevents the initial control torque of the engine from being excessively reduced at the start of a traction control. By this construction, it is possible to prevent an initial control torque from being excessively reduced due to a misjudgment of a friction coefficient of a surface of an upward or downward sloping road to insure an acceleratability of a vehicle.

Traction control device for vehicle

A traction control system for a four-wheel steerable vehicle includes a reference value generating circuit for generating a reference value for detecting a slippage of a drive wheel in a driving state, an output torque control device for controlling the torque of the drive wheel on the basis of an output from said reference value generating circuit so as to bring said drive wheel into a predetermined slipping state, and a reference value correcting circuit for correcting the reference value on the basis of a rear wheel steering angle. This makes it possible to insure a steering stability in a critical condition when a misalignment has been produced in phases of the front and rear wheels.

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Wako, Japan

Toru Ikeda