Nissan Motor Company Limited

Saburo Tomikawa

Katsuhiko Kawamura

Osamu Matsuno

A hybrid vehicle control apparatus controls an engine that rotates at least one first wheel and a mechanically independent electric motor that rotates at least one second wheel. The hybrid vehicle control apparatus stabilizes the vehicle driving performance when there is a change in the portion of the total drive torque that should be carried by the engine. Thus, the hybrid vehicle control apparatus prevents degradation of the vehicle driving performance due to the response of the engine when the drive force distribution is shifted. The target drive torque of the engine driven wheels is calculated by multiplying the total target drive torque by a rear wheel drive force distribution ratio. The target drive torque of the motor driven wheels is calculated by estimating the actual drive torque of the engine driven wheels and subtracting this estimated value from the total target drive torque.

Hybrid vehicle control apparatus

A hybrid vehicle control apparatus controls an engine that rotates at least one first wheel and a mechanically independent electric motor that rotates at least one second wheel. The hybrid vehicle control apparatus stabilizes the vehicle driving performance when drive forces are obtained from both the engine and the electric motor. Thus, the hybrid vehicle control apparatus stabilizes 4WD travel over a wide range using an engine and a comparatively small electric motor. The target front (motor-driven) wheel drive torque is calculated by subtracting the target rear (engine-driven) wheel drive torque from the total target drive torque. Meanwhile, the motor torque upper limit value is estimated from the motor rotational speed. If the front wheel target drive torque exceeds the motor torque upper limit value, the drive torque &Dgr;T, which corresponds to the amount by which the motor torque is insufficient, is added to the rear wheel target drive torque.

An EGR system comprises a vacuum-operated EGR valve and an auxiliary valve of a diaphragm type for assisting the operation of the EGR valve. A diagnostic control unit monitors an engine rotational fluctuation parameter such as a misfire parameter under the condition of EGR and judges that there is a possibility of abnormality in the auxiliary valve when the fluctuation parameter is greater than a first judgment value. In response to this judgment, the diagnostic control unit forcibly cuts off the EGR and calculates the fluctuation parameter under the condition of EGR cutoff. The diagnostic control unit concludes that the auxiliary valve is abnormal when the fluctuation parameter in the EGR cutoff state is smaller than or equal to a second judgment value which is smaller than the first judgment value.

Growing community of inventors

Isehara, Japan

Saburo Tomikawa