Honda Giken Kogyo Kabushiki Kaisha

Syouji Suzuki

Kunimichi Hatano

Takeshi Kojima

Toshio Yahagi

Kazuaki Fukami

A method of controlling the driving state of a vehicle in which an antilock brake control for eliminating a locking tendency of a wheel during braking can be carried out, and a four-wheel drive state and a two-wheel drive state can be switched from one to another. A monitored estimated vehicle speed is calculated on the basis of highest one of wheel speeds of the vehicle wheels and a value is detected by a longitudinal acceleration/deceleration sensor for detecting a longitudinal acceleration or deceleration of a vehicle speed, and a judgement speed is determined at a value lower than the monitored estimated vehicle speed. The vehicle speed is also independently determined based upon the speed of each of the vehicle wheels. The four-wheel drive state is switched to the two-wheel drive state in response to highest one of vehicle speeds independently calculated on the basis of the wheel speeds becoming equal to or less than the judgement speed in the four-wheel drive state. Thus, when the brake depression force is small, the four wheels are prevented from gradually falling into their locked states, with the four-wheel drive state being maintained when the antilock brake control is not carried out.

Process for controlling travel state during braking in vehicle

A process for calculating estimated vehicle speeds on the basis of wheel speeds of the vehicle wheels and a value resulting from addition of an offset value corresponding to an output error including a dispersion component and a slope component of an output from a longitudinal acceleration/deceleration sensor to a detection value detected by the longitudinal acceleration/deceleration sensor. In a condition in which it is determined that a vehicle is traveling at a substantially constant speed for a relatively long period of time, a first correction amount is calculated from an average value of variations in wheel speeds and an average value of outputs from the longitudinal acceleration/deceleration sensor during the long period of time. In a condition in which it is determined that the vehicle is traveling at a substantially constant speed for a relatively short period of time, a second correction amount is calculated from the average value of variations in wheel speeds and the average values of outputs from the longitudinal acceleration/deceleration sensor during the short period of time. An amount of correction of the zero point of the longitudinal acceleration/deceleration sensor is determined by the first correction amount, and the correction of the offset value is determined by the second correction amount.

Process for calculating estimated vehicle speeds

An antilock brake control method for a four-wheel drive vehicle including calculating an estimated vehicle speed on the basis of a wheel speed of a wheel and a value obtained by adding an offset value to an output from a longitudinal acceleration/deceleration sensor for detecting a longitudinal acceleration or deceleration of the vehicle. When it is detected that all of the four wheels are in their spinning state, the addition of the offset value to the output from the longitudinal acceleration/deceleration sensor is stopped, and the estimated vehicle speed is calculated on the basis of the wheel speed and the output from the longitudinal acceleration/deceleration sensor.

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Wako, Japan

Syouji Suzuki