Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
1998-10-05
2001-05-29
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C701S036000, C701S038000, C701S070000, C280S124159, C280S005501, C280S005504, C280S005507, C280S005515
Reexamination Certificate
active
06240348
ABSTRACT:
INCORPORATION BY REFERENCE
The disclosure of Japanese Patent Application No. HEI 9-346885 filed on Dec. 16, 1997 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vehicle height adjust control apparatus and method that maintains the vehicle height at a target vehicle height.
2. Description of the Related Art
A conventional problem occurs when adjustment of a vehicle height to a target vehicle height is attempted while the vehicle is stopped with a brake pedal depressed. The vehicle height adjustment cannot be achieved because the wheels are prevented from rotating by arms between the vehicle body and the wheels that restrain the wheels and therefore prevent them from moving. However, pressure in the fluid pressure actuators for changing the vehicle height in normal conditions changes irrespective of a change in the vehicle height, so that when the brake pedal is released from the depression, the vehicle height is rapidly changed. To solve this problem, a vehicle height adjust control apparatus as described in, for example, Japanese Patent Application Laid-Open No. Hei 2-279410, suspends vehicle height adjust control under a condition as described above, or ceases the vehicle height adjust control if no substantial vehicle height change is achieved although the vehicle height adjust control is continued for a predetermined length of time. The aforementioned laid-open patent application also discloses a technology wherein while the wheels are restrained from rotating, the fluid pressure in the fluid pressure actuators is changed corresponding to the amount of shift of the actual vehicle height from the target vehicle height. This technology is intended to solve the problem that exists when the vehicle height adjustment is to be re-executed and the actual vehicle height is considerably deviated from the target vehicle height so that readjustment of the vehicle height needs to be performed and the convergence of the vehicle height to the target vehicle height is correspondingly delayed,
However, in real vehicles, it is possible, though it may be difficult, to change the vehicle height to some extent even while the vehicle is stopped with the brake pedal depressed, because the bushings and the like in the vehicular suspension devices can deform. In a case where the height of a vehicle is reduced due to an occupant or a luggage load added to the vehicle while the vehicle is stopped on a slope with the brake pedal operated, the re-starting of the vehicle without adjusting the vehicle height may result in a problem of the hitting of bound stoppers in the suspension devices or a problem of interference between a lower portion of the vehicle and bumps in a bad road. In such a situation, even though the vehicle is stopped with the brake pedal depressed, vehicle height adjustment is needed, and it is not preferable to entirely stop the vehicle height adjustment as in a conventional art.
Furthermore, in a conventional vehicle height adjust control apparatus wherein the control is ceased if no vehicle height change is achieved although vehicle height adjustment is continued for a set length of time as described above, the set length of time needs to be relatively long in order to set the vehicle height to a target vehicle height while the vehicle height is oscillating, for example, while the vehicle is running. However, if this set time is excessively long, the supply of fluid to fluid pressure actuators may continue for a long time while the vehicle height does not change. Conversely, if the set time is excessively short, the vehicle height may not be precisely or properly adjusted to a target vehicle height while the brake pedal is not operated, or almost no vehicle height change is caused while the brake pedal is depressed, so that the aforementioned problems of the hitting of bound stoppers and interference of a lower portion of the vehicle and a road surface may occur. Furthermore, in a conventional vehicle height adjust control apparatus wherein while the wheels are restrained from rotating, the fluid pressure in the fluid cylinders is changed corresponding to the amount of shift of the actual vehicle height from the target vehicle height as described above, it becomes necessary to use complicated component parts for regulating pressure, for example, pressure control valves and the like.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a simply-constructed vehicle height adjust control apparatus and method that eliminates the problems of the hitting of bound stoppers and interference of a lower portion of the vehicle and a road surface, minimizes useless or ineffective operation of the actuators for changing the vehicle height, and quickly adjusts the vehicle height to a target vehicle height after the brake pedal is released from depression.
According to one aspect of the invention, there is provided a vehicle height adjust control apparatus including an actuator capable of changing a height of a vehicle, a vehicle height detection device for detecting a vehicle height, an adjustment control device for, if the vehicle height detected by the vehicle height detection device shifts upward or downward from a target vehicle height, increasing or reducing the vehicle height by controlling the actuator so that the vehicle height becomes substantially equal to the target vehicle height, a stop detection device for detecting a stopped state of the vehicle, and a braking detection device for detecting a brake pedal depressing operation. A lowering restriction device is provided in the adjustment control device for restricting a vehicle height adjustment in a reducing direction if the stopped state of the vehicle is detected by the stop detection device and the brake pedal depressing operation is detected by the braking detection device.
The adjustment control device may include a start determination device for determining whether an amount of upward or downward shift of the vehicle height detected by the vehicle height detection device from the target vehicle height is greater than a predetermined value and, if it is determined that the amount of upward or downward shift is greater than the predetermined value, starting a vehicle height adjustment and a vehicle height change device for, when it is determined by the start determination device that the vehicle height adjustment be started, changing the vehicle height by controlling the actuator so that the vehicle height detected by the vehicle height detection device becomes substantially equal to the target vehicle height. In this construction, the lowering restriction device may include a determination inhibition device for inhibiting determination regarding the amount of upward shift from being performed by the start determination device, or a determination value change device for changing the predetermined value used in relation to determination regarding the amount of upward shift, to an increased value.
The adjustment control device may also include a start determination device for counting a number of times that an amount of upward or downward shift of the vehicle height detected by the vehicle height detection device from the target vehicle height exceeds a predetermined value and, when the counted number of times exceeds a predetermined number, starting a vehicle height adjustment, and a vehicle height change device for, when it is determined by the start determination device that the vehicle height adjustment be started, changing the vehicle height by controlling the actuator so that the vehicle height detected by the vehicle height detection device becomes substantially equal to the target vehicle height. In this construction, the lowering restriction device may include a determination number change device for changing the predetermined number used in relation to determination regarding the amount of upward shift, to an increased number.
In the vehicle
Sato Atushi
Shono Shoichi
Cuchlinski Jr. William A.
Mancho Ronnie
Oliff & Berridg,e PLC
Toyota Jidosha & Kabushiki Kaisha
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