Starting Low Compression Ratio Rotary Wankel Diesel Engine

The single stage rotary Wankel engine is difficult to convert into a diesel version having an adequate compression ratio and a compatible combustion chamber configuration. Past efforts in designing a rotary-type Wankel diesel engine resorted to a two-stage design. Complexity, size, weight, cost and performance penalties were some of the drawbacks of the two-stage Wankel-type diesel designs. This paper presents an approach to a single stage low compression ratio Wankel-type rotary engine. Cold starting of a low compression ratio single stage diesel Wankel becomes the key problem. It was demonstrated that the low compression single stage diesel Wankel type rotary engine can satisfactorily be cold started with a properly designed combustion chamber in the rotor and a variable heat input combustion aid. A 10.5 compression ratio rotary Wankel-type engine was started in 15 secs at −10°C inlet air temperature. High cranking speeds and white smoke were the biggest drawbacks of this design.