Six-stroke engine

Abstract: In the present study, a four-stroke cycle gasoline engine is redesigned and converted into a six-stroke cycle engine and experimental study has been conducted using gasoline and acetylene as fuel with water injection at the end of the recompression stroke. Acetylene has been used as an alternative fuel along with gasoline and performance of the six-stroke spark ignition (SI) engine with these two fuels has been studied separately and compared. Brake power and thermal efficiency are found to be 5.18 and 1.55% higher with acetylene as compared to gasoline in the six-stroke engine. However, thermal efficiency is found to be 45% higher with acetylene in the six-stroke engine as compared to four-stroke SI engine. The CO and HC emissions were found to be reduced by 13.33 and 0.67% respectively with acetylene as compared to gasoline due to better combustion of acetylene. The NOx emission was reduced by 5.65% with acetylene due to lower peak temperature by water injection. The experimental results showed better engine performance and emissions with acetylene as fuel in the six-stroke engine.

Abstract: In this study, the effects of the amount of water injection and timing on engine performance were investigated in a water injection with exhaust heat recovery six-stroke engine converted from single cylinder, four-stroke, spark ignition engine. The experiments were performed at constant injection timing and four different injection pressures (25, 50, 75 and 100 bar) at full load and stoichiometric air/fuel ratio (λ = 1). Experimental findings were evaluated according to first and second law of thermodynamics. The highest brake power was measured at 3000 rpm as 1345.9 kW when the 13.44 mg/cyc water was injected at TDC. At this time, thermal efficiency, thermodynamic efficiency and irreversibility were calculated 14.73%, 21.88% and 52.57% respectively. It was seen that brake power, thermal efficiency and thermodynamic efficiency decreased but irreversibility increased when the different quantity of water was injected at the same engine speed and different injection timing. As a result, water injection timing and the quantity of water are important in order to provide optimum exhaust heat recovery for higher engine performance.

Abstract: In six stroke engine, there are additional two strokes, namely another power and exhaust strokes. The engine works through harnessing wasted heat energy created by the fuel combustion. After the combustion stage water is injected into the super- heated cylinder. The water explodes into steam and force the piston down. It in turn helps to cool the engine. That resulted in normal levels of power but using much less fuel. It also has the advantage of not requiring an external cooling system. In order to achieve these benefits, major modifications of conventional internal combustion engine must be done. In this paper the modification of the conventional four stoke internal combustion engine is illustrated to convert it into six stroke engine.