A cold startability study was carried out on a single-cylinder research engine. Engine cooling was achieved by circulating chilled alcohol through the engine. Cold air was supplied with the help of compressed air and vortex tubes. A technique was developed to measure white smoke output of the engine. Charge air temperatures for a non-firing engine were measured by using thermocouples and high-speed data acquisition techniques.
High-speed data acquisition techniques were used for quantitative determination of cold startability by comparing cranking torque, black smoke, white smoke, and cylinder pressure. Cold startability was measured for compression ratios of 14:1, 16:1 and 18:1 at 32°F, 14°F, and −4°F.
The study indicated desirability of lower compression ratios for performance and higher compression ratios, higher cranking speeds and retarded injection timings for improved cold startability.