Experimental Research on Two-stroke and Four-stroke Gasoline Engine with Alcohol Fuel

The purpose of this research is to explore experimentally the influences of gasoline-alcohol blended fuel on the performance of single cylinder two-stroke and inline-four cylinder gasoline engines. The research was conducted within 30% of alcohol and by blending 98 unleaded gasoline and 95% alcohol to form alternative fuels of various blending ratios. The engine performances, containing: engine speed, torque, output power, driving load, fuel pressure, manifold vacuum and oxygen content variation, were tested to obtain the optimum fuel blending ratio for the purpose of energy-saving. The research is divided into two parts: firstly, the test was carried out based on the engine of single cylinder two-stroke mower with 22c.c. air displacement, whereas a test bench and a power testing equipment were developed depending on the performance of the power system. Under different speeds, the alcohol-gasoline blended fuel of different blending ratios (3%-15%) was used to explore the difference with respect to torsion, torque, output power and driving load of low horsepower engine versus that without alcohol. Secondly, the test was performed using a 1834c.c in-line four cylinder engine, which consists of an ECM control system, a sensor (input component) and an actuator (output component). Of which, ECM can control the actuator according to the signals from the sensor, so as to optimize the working status of the engine for meeting various operating demands. For alcohol-gasoline blend fuel with different blending ratios (1%-30%), the fuel pressure, manifold vacuum, oxygen content and air flow variation were researched and compared with those without alcohol. The experiment results show that, the torsion, torque, output power and driving load of two-stroke engine can achieve better performance when the proportion of alcohol is 10%; as for four-stroke engine, when the proportion of alcohol is 20%, a better efficiency of fuel pressure can be realized; when the proportion of the alcohol is 15%, a better efficiency of manifold vacuum and air flow can be realized; when the proportion of alcohol is 10%, a better efficiency of oxygen content can be realized. The research results can thus provide a reference for the researchers in vehicle industry.