A simple on-board electric generator for road electric vehicles based on single-cylinder engine and PM-brushless generator

The article discusses the proposal, specifications and overall performance of a 10 kW electric power range extender suitable for electric plug-in and series hybrid vehicles, based on a single cylinder, four stroke internal combustion engine, derived from a motorcycle engine, modified and developed at Istituto Motori CNR of Italy, coupled with a PM generator. This unit has been thought as a low-cost mobile recharging system for city cars and small commercial vehicles and it's based on the required characteristics of a modern electric city car to define the reference power for the range extender. In the paper is explained the ratio which leaded to the adoption of a single cylinder internal combustion engine, followed by details of the main design characteristics of the unit, which has been assembled just with off-the-shelf elements, in order to reduce the cost coming from new design and making. The use of the air cooling for the electric generator (a permanent magnet axial unit) permitted to simplify the whole system, still allowing an easy packaging of the same for the final application on the vehicle. As field test, a complete description of functioning of the internal combustion engine and the generator has been reported; then the two sub-systems have been coupled together and finally tested as a whole system with conventional unleaded gasoline.