| 摘要 |
The IC engine (12) has direct fuel injection designed for good fuel economy under moderate loads using a stratified weak mixture. Its crankshaft (18) is directly connected to a fly-wheel integrated with the rotor (16) of the electric motor (14), which interposed between the engine and the transmission (20). An electronic management unit (22) controls engine and motor operation, primarily to meet the net torque output demanded by the driver through accelerator pedal depression. Demand is met by the engine, the motor, sometimes in generator mode, intervening to sustain weak-mixture engine operation and to set exhaust gas temperatures at values consistent with pollution control requirements. Exhaust gas treatment includes a catalytic converter with a NOx trap retaining oxides of nitrogen. For correct trap operation gas temperatures should lie between e.g. 250 deg C and 450 deg C. Above a threshold engine torque value, in weak-mixture running, the higher figure will be exceeded. To prevent this, while maintaining fuel economy, the management unit will, if the battery is adequately charged, meet the excess torque demand using the motor. To raise low gas temperatures into the trap range the motor is run as a generator, artificially increasing the engine load, the excess energy being stored in the battery. High temperatures (600 deg C) for sulfur oxide purging are obtained in the same way.
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