Traction control system for motor vehicles
AssigneeAkebono Brake Industry Co., Ltd.
InventorNaoyuki Hagiya
Life of this patent
Estimating the term…
Abstract
A traction control system for motor vehicles in which the occurrence of on-driving wheel speed is monitored during a time interval which begins when the traction control starts to a predetermined time period which elapses therefrom. In the event that no occurrence of no-driving wheel speed is detected during the aforementioned time interval, the throttle opening degree command value prevailing at the end of the time interval is decreased to a predetermined lower limit value in response thereto, while at the same time the control is changed to a low friction coefficient control mode.
Claims9
A traction control system for motor vehicles, wherein a control threshold value for a driven wheel speed is selected based upon a non-driven wheel speed which occurs when the motor vehicles start, and a throttle valve opening is controlled by a throttle driving mechanism so that a driven wheel speed approaches said control threshold value, thereby preventing an excessive slip of the driven wheel when the motor vehicle starts, said traction control system comprising:
- first means for measuring a time period in which the traction control is started and during said time period the non-driven wheel speed is detected as being zero and for providing a signal at a time point when the measurement of said time period becomes equal to or exceeds a predetermined value, wherein said predetermined value measures a point in time when traction control begins to a point where said time period elapses, wherein said predetermined value is the difference between the control threshold value for the driven wheel speed and the control threshold value for a normal mode;
- and
- second means for decreasing said throttle opening degree down to a predetermined lower limit value for a low .mu. control mode in response to said signal provided by said first means, thereby changing the traction control to a controlling mode for a coefficient of friction for a road surface, said control threshold value of the driven wheel speed dropping from a high level to and approaching the non-driven wheel speed level during said time period.
A traction control system for motor vehicles, comprising:
- (a) means for setting up, a first and then a second control threshold value for a driving wheel speed, a value provided by adding a predetermined first value to a non-driven wheel speed when the motor vehicle starts, and a value provided by adding a predetermined second value to said non-driven wheel speed, said value being less than said first value;
- (b) means for starting traction control at a time point when the increasing driven wheel speed first exceeds said first control threshold value, performing throttle closing control at a predetermined first closing speed, and measuring a period of time during which the non-driven wheel speed is not generated from the time point when the traction control is commenced;
- (c) means for performing a throttle opening control at a predetermined first opening speed whenever a high peak of the driven wheel speed occurs where the driven wheel speed is changed from an increase to a decrease, before the period of time during which the non-driven speed is not longer than a predetermined period of time, and performing throttle closing control at said first closing speed whenever the increasing driven wheel speed exceeds said first control threshold value, of the driven wheel speed, said control threshold value dropping from a high level to and approaching the non-driven wheel speed level during said time period;
- and
- (d) means for reducing the throttle opening degree to a preset lower limit value when the non-driven wheel speed is not generated for said predetermined period of time, and thereafter, with said second threshold value as reference, performing throttle control for opening/or closing the throttle at a second opening speed or at a second closing speed lower than said first opening speed or said first closing speed.
Dependencies are inferred from the claim text.