Vehicle slip control apparatus

Claim 2

A slip control apparatus of a vehicle for preventing a driving wheel (2,3) of the vehicle from excessively slipping on a road surface, comprising output torque adjusting means (14), slip detecting means (64,65,66,U S ) for detecting the slip of the driving wheel (2,3) and feedback control means for feedback controlling the output torque adjusting means (14) in response to a signal of the slip detecting means (64,65,66,U S ) so as to make the slip a target slip value (S ET ), characterized by a slip reduction detecting means (U S ) which is apt to detect a reduction of the slip from a relatively large slip amount towards said target slip value (S ET ) and a recovery control means (U S ) for controlling the torque adjusting means (14) in an open loop control in lieu of said feedback controlling, so as to increase the output torque in response to a signal of the slip reduction detecting means (U S ) before the slip has been reduced to said target slip value (S ET ).

Claim 3

Apparatus as claimed in claim 1 or 2 characterized in that it comprises slip state detecting means (U S ) for detecting the state of the slip and target value altering means for altering said first and second target slip values in response to an output of said slip state detecting means in accordance with the detected state of the slip.

Claim 4

Apparatus as claimed in any of claims 1 to 3 characterized in that said slip state detecting means (U S ) is apt to detect the maximum acceleration of the vehicle body when the slip is reduced.

Claim 5

Apparatus as claimed in any of claims 1 to 4 characterized in that it comprises brake releasing means (U S ) for suspending the slip control performed by said second slip control means (U B ) when the actual slip has a predetermined slip value smaller than said second target slip value (S BT ).

Claim 6

Apparatus as claimed in claim 5 characterized in that said predetermined slip value is set to be a value between said first and second target slip values (S ET , S BT ).

Claim 7

Apparatus as claimed in any of claims 1 to 6 characterized in that said slip detecting means (64,65,66,U S ) calculate a slip ratio of the driving wheel (2,3) on the basis of at least the rpm of the driving wheel (2,3).

Claim 8

Apparatus as claimed in any of claims 2 to 7 characterized in that it comprises a slip occurrence detecting means (U S ) for detecting the state of occurrence of the slip and an increased-torque amount altering means (U S ) for altering the amount by which the output torque is increased by said recovery control means (U S ) in response to a signal of said slip occurrence detecting means (U S ).

Claim 9

Apparatus as claimed in claim 8 characterized in that said slip occurrence detecting means (U S ) is apt to detect the maximum acceleration of the vehicle when the slip is reduced and in that said increased-torque amount altering means (U S ) is apt to increase the torque amount when said maximum acceleration of a vehicle increases.

Claim 10

Apparatus as claimed in any of claims 1 to 9 characterized in that it comprises limiting means (U S ) for limiting the speed of brake operation so as not to exceed a predetermined maximum value of brake operation speed.

Claim 11

Apparatus as claimed in claim 10 characterized in that it further comprises maximum speed value altering means (U S ) for altering said predetermined maximum speed value in such a way that the maximum speed value increases when the vehicle speed increases.

Claim 12

Apparatus as claimed in any of claims 1 to 11 characterized in that the power source of the vehicle is an internal combustion engine (6) of which the output torque is adjusted by adjusting the intake air amount and in that said torque adjusting means (14) is apt to adjust the intake air amount of the internal combustion engine (6).

Claim 13

Apparatus as claimed in any of claims 7 to 12 characterized in that it comprises backup control means for controlling the torque adjusting means (14) in an open loop control so as to gradually increase the output torque when the slip has become smaller than a predetermined backup control slip value which is smaller than said target slip value (S ET ).

Claim 14

Apparatus as claimed in claim 13 characterized in that it comprises absorb control means (U S ) for providing a smooth transition by means of an open loop control between said backup control and said feedback control.

Claim 15

Apparatus as claimed in claim 14 characterized in that the absorb control means (U S ) is set so as to control the torque adjusting means (14) to assume an adjustment value which is between the adjustment value obtained by said backup control means and the adjustment value obtained by said feedback control means.

Claim 16

Apparatus as claimed in any of claims 1 to 15 characterized in that it comprises left slip detecting means (64, U S ) for detecting the state of slip of the left driving wheel (2) of the vehicle, right slip detecting means (65, U S ) for detecting the state of slip of the right driving wheel (3) of the vehicle, selecting means for selecting either one of the signals of said left and right slip detecting means (64,65,U S ) on the basis of a predetermined condition, left braking force adjusting means (31), right braking force adjusting means (30), a power source (6) in common for both driving wheels (2, 3), whereby said second slip control means (U B ) comprises a respective slip control means for controlling of said left and right braking force adjusting means (31,30) in response to an output of said left and right slip detecting means (64,65,U S ), respectively, and whereby said first slip control means (U T ) controls said output torque adjusting means in response to an output of said selecting means so as to cause the slip of the driving wheels (2,3) to become said first target slip value (S ET ) which has been selected by the selecting means.

Claim 17

Apparatus as claimed in claim 16 characterized in that said selecting means is set so as to select the signal corresponding to a smaller slip amount in the case when only either one of the slip control means for the left and right braking force adjusting means (31,30) is operating and to select the signal corresponding to the greater slip amount in the case when both slip control means are operating.