| DETERMINATION OF THE THEORETHICAL AND TOTAL EFFICIENCY OF THE FIVE-STROKE SI ENGINE |
| M. NOGA, B. SENDYKA |
| Cracow University of Technology |
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| ABSTRACT |
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The paper presents the derivation of a formula to determine the thermal efficiency of thermodynamic cycle of the engine with expansion ratio two times higher than compression ratio with respect to the thermal efficiency of the Otto cycle. Analysis of the thermal efficiency of the five-stroke engine cycle for the case in which the expansion ratio is two times higher than the compression ratio has been presented in this study for the first time. Using the derived model, a comparison was made between the thermal efficiency of four-cylinder five-stroke engine cycle and Otto cycle describing the work of fourstroke spark ignition engine. The analysis showed that the efficiency of the five-stroke engine cycle is higher by about 12% than it is for the Otto cycle, for the compression ratio used afterwards in the test engine. This fact constitutes an innovation of the presented work. Theoretical results have been verified during experimental research of prototype of the five-stroke engine constructed at Cracow University of Technology on the basis of in-line four-cylinder four-stroke engine. Analysis of the results indicated that at comparative value of the load, the five-stroke engine achieved total efficiency higher by an average of 11% at 1800 rpm and 19.4% at 2000 rpm, than it was in the case of engine realizing four-stroke cycle. |
| Key Words:
Five-stroke engine, Spark ignition, Additional expansion, Increase of thermal efficiency |
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