| 摘要 |
<P>PROBLEM TO BE SOLVED: To avoid the deterioration of the traveling performance of a vehicle caused by the lowering of an engine output caused by power generation for motor four-wheel driving. <P>SOLUTION: A motor torque command value dTm rises at a time t1 when an amount of a front-wheel drive slip reaches a value not smaller than a four-wheel drive start determination value, thus bringing about a four-wheel drive state that rear wheels are driven, too. Since a large target drive force cannot be set because a road-face friction coefficient is so extremely small as a frozen road or the like has until a time t2 comes when the target drive force reaches a target drive force setting value, the maximum value dTmmax of a motor torque command is made to be a motor torque maximum value Tmmax that is necessary for the elimination of the front-wheel drive slip. After the time t2, a large drive-force drive state that the large target drive force can be set because the road-face friction coefficient is so comparatively large as a snow-compacted road has, the dTmmax is lowered to Tmmax×0.5. By this, an amount of engine power consumed for the driving of a generator can be reduced, thus avoiding the deterioration of the traveling performance. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
