A low pressure pneumatic direct injection engine by AR Combustion concept has been developed. In this engine, the scavenging process is performed by air only, prior to the fuel feed process, which minimizes the fuel short-circuiting accompanying the scavenging flow. The wide spray form generated by the rotary type injector facilitates homogeneous combustion even in the high speed high load range, which promises higher maximum power output. Meanwhile, in the light load range, AR Combustion effectively solves the irregular combustion.The bench test results show a remarkable reduction in the exhaust emissions and fuel consumption while successfully maintaining high power output of original two-stroke engine. Moreover, actual vehicle tests using a motorcycle reveal its good potential as a vehicle engine.