Traction control system for motor vehicles

Claim 2

A traction control system for motor vehicles, wherein a control threshold value for a driving wheel speed is set up on the basis of a non-driving wheel speed which occurs when the motor vehicle starts, and a throttle opening degree is controlled such that the driving wheel speed approaches said control threshold value, thereby preventing an excessive slip of the driving wheel when the motor vehicle starts, said traction control system comprising: first means for providing a signal when time period from a time point when the traction control is commenced to a time point when non-driving wheel speed is generated is equal to or more than a predetermined value; and second means for decreasing said throttle opening degree down to a predetermined lower limit value in response to said signal, thereby changing the traction control to a low-µ control mode.

Claim 3

A traction control system according to Claim 1, wherein the control threshold value for the driving wheel speed is set up by adding a predetermined value to the non-driving wheel speed.

Claim 4

A traction control system according to Claim 1, wherein throttle closing control is performed from a time point when the increasing driving wheel speed exceeds said control threshold value, and throttle opening control is performed from a time point when a high peak of the driving wheel speed occurs where the driving wheel speed is changed from increase to decrease.

Claim 5

A traction control system fro motor vehicles according to Claim 1, wherein the throttle opening/closing speed for the low-µ control mode is made to be lower than that for the normal control mode.

Claim 6

A traction control system according to Claim 1, wherein the control threshold value for the driving wheel speed in the normal control mode is set up by adding a predetermined first value to the non-driving wheel speed, and the control threshold value for the driving wheel speed in the low-µ control mode is set up by adding a predetermined second value to the non-driving wheel speed, said predetermined second value being lower than said predetermined first value.

Claim 7

A traction control system according to Claim 1, wherein the traction control is returned from the low-µ control mode to the normal control mode when an acceleration of the non-driving wheel exceeds a predetermined value during the low-µ control mode.

Claim 8

A traction control system according to Claim 1, wherein the traction control is returned from the low-µ control mode to the normal control mode when a condition that an accelerator pedal is not depressed persists longer than a predetermined period of time during the low-µ control mode.

Claim 9

A traction control system for motor vehicles, comprising: (a) means for setting up, as first and second control threshold values for a driving wheel speed respectively, a value providing by adding a predetermined first value to a non-driving wheel speed when the motor vehicle starts, and a value provided by adding a predetermined second value to said non-driving wheel speed, said value being less than said first value; (b) means for starting traction control at a time point when the increasing driving 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 for which a condition that the non-driving wheel speed is not generated persists from the time point when the traction control is commenced; (c) means for performing throttle opening control at a predetermined first opening speed whenever a high peak of the driving wheel speed occurs where the driving wheel speed is changed from increase to decrease, before the period of time for which the condition that the non-driving wheel speed is not generated persists, becomes longer than a predetermined period of time, and performing throttle closing control at said first closing speed whenever the increasing driving wheel speed exceeds said first control threshold value; and (d) means for reducing the throttle opening degree to a preset lower limit value in case the condition that the non-driving wheel speed is not generated persists for said predetermined period of time, and thereafter, with said second threshold value as reference, performing throttle opening/closing control at a second opening/closing speed lower than said first opening/closing speed.

Claim 10

A traction control system for motor vehicles, comprising: (a) means for setting up, as first and second control threshold values for a driving wheel speed respectively, a value providing by adding a predetermined first value to a non-driving wheel speed when the motor vehicle starts, and a value provided by adding a predetermined second value to said non-driving wheel speed, said value being less than said first value; (b) means for starting traction control at a time point when the increasing driving 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 for which a condition that the non-driving wheel speed is not generated persists from the time point when the traction control is commenced; (c) means for performing throttle opening control at a predetermined first opening speed whenever a high peak of the driving wheel speed occurs where the driving wheel speed is changed from increase to decrease, before the period of time for which the condition that the non-driving wheel speed is not generated persists, becomes longer than a predetermined period of time, and performing throttle closing control at said first closing speed whenever the increasing driving wheel speed exceeds said first control threshold value; and (d) means for reducing the throttle opening degree to a preset lower limit value in case the condition that the non-driving wheel speed is not generated persists for said predetermined period of time, and thereafter, with said second threshold value as reference, performing throttle opening/closing control at a second opening/closing speed lower than said first opening/closing speed.

Claim 11

A traction control system according to Claim 8, wherein the control threshold value for the driving wheel speed is changed from said first control threshold value to said second control threshold value in case the condition that non-driving wheel speed is not generated persists for one second from the time point when the traction control is commenced.