增程式车用发动机更加关注电驱动车辆行驶工况下，电机驱动功率道路行驶阻力功率平衡状态时的发动机燃油经济性。基于这种特点，开发了一种增程式电动车辆专用发动机，发动机工作循环采用基于阿特金森循环的高膨胀比设计，发动机可以提供额定35 kW的发电功率输出。匹配车辆后，对比同等动力水平下的传统奥托循环发动机与阿特金森循环增程器的整车等速行驶经济性，结果表明，采用阿特金森循环的发动机增程器具有更高的经济性和更广泛的车型覆盖能力。

The balance between the motor driving power and the road driving resistance power was paid more attention in respect of the fuel economy of engine for range extended vehicle. Based on this feature, a special engine was developed for range extended electric vehicle. The engine adopted a high expansion ratio design based on the Atkinson cycle and could provide the power generation output of 35 kW. After matching the electric vehicle, the comparison of vehicle driving economy at constant speed was conducted between the Otto cycle engine and Atkinson cycle engine range extender based on the same power. The results show that the engine for range extender of Atkinson cycle has higher power generation efficiency with a wider range of vehicle type.