A NEW CONCEPT OF EXTERNALLY HEATED ENGINE - COMPARISONS WITH THE STIRLING ENGINE

This paper presents a new concept of the externally heated value (EHV) engine. Air can be used as a working medium in the closed cycle of th is engine. Heat delivered to the working air can come from a combustio n chamber or another heat generator of an arbitrary type. The engine c onstruction and the thermodynamic cycle performed by it are original a nd entirely different fi om the well-known Stirling engine. The main d isadvantage of the Stirling engine is its low power density, that is t he low power obtained per litre of the engine cylinder volume. In the case of the engine presented here it is possible to achieve power dens ity and efficiency similar to those typical of advanced internal combu stion engines. Comparisons between the power of the Stirling engine an d the power of the new engine have been performed for the same engine capacity, rotational frequency and maximum and minimum temperatures of the cycle. At the same minimum pressure of the working gas in both en gines, the power of the EHV engine is several times higher than that o f the Stirling engine, while, on the other hand, at the same maximum p ressure of the working gas in both engines, the power of the EHV engin e is 20 per cent higher than that of the Stirling engine power. The ef ficiencies of both engines do not differ significantly from each other .