Experimental evaluation of a 4-cc glow-ignition single-cylinder two-stroke engine

The performance of a 4cc two-stroke single cylinder glow plug engine was assessed at wide open throttle for speeds ranging from 2000 to 7000RPM. The engine performance was mapped for the stock aluminum head and one composed of titanium, which was printed using additive manufacturing. The engine was mounted to a motoring dynamometer and the maximum torque was determined by adjusting the fuel flow. Maximum torque occurred around 3000 to 3500RPM and tended to be higher when using the aluminum head. At slower speeds, the titanium head produced slightly higher torque. For each test condition, maximum torque occurred at leaner conditions for the titanium head compared to the stock aluminum one. Higher efficiencies were observed with the aluminum head for speeds greater than 3000RPM, but the titanium heads provided better efficiency at the lower speed points. The titanium head was equipped with an in-cylinder pressure sensor and the combustion performance was assessed at maximum torque for speeds of 4000, 6000, and 7000RPM. The peak cylinder pressure increased with decreasing speed, while the indicated mean effective pressure increased with speed. The Coefficient of variance (COV) for indicated mean effective pressure (IMEP) was less than 10% for each condition.