The Wishart Cycle for Internal Combustion Engines

The six thermodynamic processes which comprise the Wishart cycle for heat engines are defined and the cycle thermal efficiency is derived in this paper. The cycle is analysed by determining the effect on the cycle thermal efficiency with changes in the four independent cycle properties being the compression ratio, the expansion ratio, the quantity of fuel heat added and the quantity of otherwise rejected heat reused. Those properties make it possible to achieve in an internal combustion engine based on the cycle conditions whereby the component processes can be performed more ideally, in engine components suited for each process, than those which are possible for sequential processes operating in a single cylinder. The mode of operation and configuration of an engine are described to demonstrate that controlled combustion at low temperature, the elimination of detonation, improved power balance and relatively high thermal efficiency can be achieved in a practical internal combustion engine.