Honda Giken Kogyo Kabushiki Kaisha

Honda Motor Co., Ltd.

Seiji Ohsaki

Nobuharu Kuriki

Hideaki Shibue

Yoshiki Noro

Hiroyasu Ishizuka

Toshitaka Imai

Takahumi Maruyama

Yoshiaki Noro

Jungo Kitamura

Takumi Satou

Yousuke Yamada

Miki Matsunobu

A vehicle control apparatus for controlling a prime mover and wheel brakes which are equipped in a vehicle with an automatic transmission. The vehicle control apparatus includes a prime mover stopping unit which stops and restarts the prime mover under predetermined conditions, and a braking force retaining unit which retains braking force of each of the wheel brakes. Even if the automatic transmission is set in a neutral range, the braking force retaining unit is controlled to retain the braking force of the wheel brakes for a first predetermined time after the operation of a brake operation member is disengaged.

Vehicle control apparatus

A braking force retaining unit has a cut-off valve and a control unit. The cut-off valve retains predetermined brake hydraulic pressure at the wheel cylinders until a predetermined releasing condition is established, even after the depression of a brake pedal is released when a vehicle is stopped. When the predetermined releasing condition is established, the retained brake hydraulic pressure is released, when the depression of the brake pedal is released, the control unit controls the cut-off valve so as to retain the brake hydraulic pressure while reducing the retained brake hydraulic pressure at a first reduction rate. When the predetermined releasing condition is established, the control unit controls the cut-off valve so as to allow the retained brake hydraulic pressure to be reduced at a second reduction rate which is faster than the first reduction rate.

Braking force retaining unit

In an active vehicle suspension system employing a double acting type single rod hydraulic linear actuator in which a piston is provided with two pressure receiving surfaces facing two different piston chambers defined by the piston received in a cylinder and having different areas, even when the line pressure of the hydraulic oil passage is lost, the height of the vehicle body can be maintained at a fixed level and a sudden change of the height of the vehicle body can be avoided by providing a hydraulic control device which appropriately controls the pressures of the upper and lower chambers so as to be inversely proportional to the areas of the corresponding pressure receiving surfaces as the pressure supplied to the hydraulic actuator is reduced.

Hydraulic control device for active suspension system

In an hydraulic active vehicle suspension system using a linear hydraulic cylinder as a primary actuator, controlled hydraulic pressure is supplied to an upper chamber of the hydraulic cylinder defined by a smaller pressure receiving surface of the piston and the cylinder while a reduced and fixed pressure is supplied to a lower chamber of the hydraulic cylinder defined by a larger pressure receiving surface of the piston and the cylinder, and an accumulator is connected to the lower chamber so that a desired hydraulic actuation can be accomplished by the controlled hydraulic pressure while sudden forces or inputs containing high frequency components applied to the lower chamber are absorbed by the accumulator. Thus, the accumulator offers a favorable response to the wheel riding over a bump or otherwise experiencing sudden movements and the absence of any accumulator connected to the upper chamber ensures a high speed response property of the system without requiring a large power capacity of the pump serving as the pressure source for the system.

Active vehicle suspension system

A hydraulic control device for an active suspension system employing a linear hydraulic cylinder including a piston connected in parallel with a spring between a wheel and a vehicle body, the piston having two pressure receiving surfaces of different areas facing two chambers separated by the piston in the cylinder, comprising a balancing valve for reducing the pressures of the two chambers to a level near the atmospheric pressure, a switch valve provided in a bypass passage between the two chambers for selectively communicating the two chambers with each other, a flow restricting orifice provided in the bypass passage; and an accumulator connected to the bypass passage capable of accommodating a change in the capacity of one of the chambers due to a piston rod extending from the piston out of the cylinder when the pressures of the two chambers are at the level near the atmospheric pressure. Alternatively, the accumulator could be replaced with a storage container connected to the bypass passage capable of accommodating an amount of actuating oil corresponding to a capacity of the cylinder. Thus, the active suspension system can serve as a workable passive suspension system when the supply of hydraulic oil is interrupted for any reason, and the reliability of the system can be improved.

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Saitama, Japan

Seiji Ohsaki