System for controlling rotation of drive wheel for vehicles and method therefor

Claim 3

A system as set forth in claim 1, wherein the seventh means comprises: (a) eighth means for detecting the first controlled variable of the first driving force adjusting mechanism; (b) ninth means for detecting the second controlled variable of the second driving force adjusting mechanism; (c) tenth means for reading a target controlled variable of the second driving force adjusting mechanism from the selected characteristic graph with respect to the detected first controlled variable; (d) eleventh means for calculating a difference between the read target controlled variable and the detected controlled variable of the second driving force adjusting mechanism; (e) twelfth means for driving the second driving force adjusting mechanism on the basis of the calculated difference by the eleventh means so as to place the second driving force adjusting mechanism on the target controlled variable position.

Claim 4

A system as set forth in claim 2, wherein the first and second driving force adjusting mechanisms are first and second throttle valves installed in series with each other in an intake air passage of the vehicular engine and the controlled variables are opening angles of the respective throttle valves.

Claim 5

A system as set forth in claim 3, wherein the twelfth means includes a stepping motor linked with the second throttle valve.

Claim 6

A system as set forth in claim 3, wherein the plurality of characteristic graphs comprise a plurality of maps to each of which a page number is allocated in an order such that as the page number increases the opening angle of the second throttle valves decreases.

Claim 7

A system as set forth in claim 5, wherein the page number is allocated to each map in such an order that page 0 indicates that the opening angle of the second throttle valve is 100% with respect to its fully open position independently of the opening angle of the first throttle valve, page 1 to page 18 indicate that the opening angle of the second throttle valve is decreased in proportion to the opening angle of the first throttle valve until the opening angle of the first throttle valve is increased to a corresponding threshold value, and page 19 indicates that the opening angle of the second throttle valve is 5% with respect to its fully open position independently of the opening angle of the first throttle valve.

Claim 8

A system as set forth in claim 6, which further comprises thirteenth means for calculating a change rate of the first speed and wherein in a first case when the change rate of the first speed is equal to or above zero and the calculated slippage is below a first lowest predetermined slippage, the sixth means selects one of the maps at page 0, in a second case when the change rate of the first speed is equal to or above zero and the calculated slippage is above the first lowest predetermined slippage but below a second lowest predetermined slippage, the sixth means selects one of the maps at page 13 or whose page number is incremented from that used in the first case, in a third case when the change rate of the first speed is equal to or above zero and the calculated slippage is increased and exceeds the second lowest predetermined slippage, the sixth means selects one of the maps at page 19 or whose page number is incremented from that used in the third case, in a fourth case when the change rate of the first speed is below zero and the calculated slippage increases and exceeds a highest predetermined slippage, the sixth means selects a predetermined value corresponding to 5% of the opening angle of the second throttle valve, and in a fifth case when the change rate is below zero and the calculated slippage is decreased and becomes below the highest predetermined slippage, the sixth means selects one of the maps whose page number is decremented from that used in the fourth case with time so that the opening angle of the second throttle valve is stepwise increased, and in a sixth case when the change rate of the first speed is below zero and the calculated slippage is decreased and becomes below a fourth lowest predetermined slippage, the sixth means selects one of the maps whose page number is page 0 or whose page number is decremented from that used in the fifth case whenever a predetermined time has elapsed.

Claim 9

A system as set forth in claim 7, wherein the four predetermined slippages are set according to characteristics of the vehicular engine and vehicle.

Claim 10

A system as set forth in claim 8, wherein the four predetermined slippages are 0.1, 0.2, 0.3 and 0.1.

Claim 11

A system as set forth in claim 5, which further comprises thirteenth means for biasing the second throttle valve toward its fully open position.

Claim 12

A system as set forth in claim 1, wherein the second means comprises eighth means for detecting a left driven wheel speed and ninth means for detecting a right driven wheel speed and wherein the second means calculates the second speed from an average speed of the left and right driven wheel speeds.

Claim 13

A system as set forth in claim 1, wherein the first means comprises a drive shaft rotation sensor for detecting a rotation of the drive shaft of the vehicle.