Impact of the content of alcohol in petroleum on the level of an unsupercharged engine’s noise

The results of the studies conducted on the chassis dynamometer for a vehicle powered with a spark-ignition engine are presented in the study. The tested vehicle was equipped with an unsupercharged engine. There was tested the noise level of the engine powered with ethyl alcohol at variable settings of the fuel injection. In the course of the tests, the dose of fuel was increased within the range from the manufacturer’s settings respectively by: 5%, 10%, 20% 30% and 50% of the nominal dose, and the ignition advance angle with reference to manufacturer’s settings was increased respectively by 00 and 30 . It was found, that the noise level for the engine powered with ethanol decreases together with the increase of the fuel’s dose, (up to about 110% of the nominal dose), and then increases. At the same time, the increase of the noise level for the increased value of the ignition advance angle was found.