Abstract
A new type external combustion engine with 4 main cylinders, 1 auxiliary cylinder for heating and valves is proposed. The operation mechanism and the theoretical heat cycle of it resemble the Otto engine except the heat transfer process. By the function of valves, the engine basically separates the compression or expansion phase from the heat exchange phases. Therefore, the total volume of the pipes in the heat exchangers can be changed independently from the compression ratio of the engine. It makes the extension of heat transfer area easy, which leads to getting high power density and high thermal efficiency. Because precise structures are not required for the heat exchangers in this engine compared with the case of the Stirling engine, it is expected that pressure drops in it and the manufacturing cost of it become low.
