Experimental investigation between pre-ignition, knocking, vibration and performance in an internal combustion engine

Otto cycle internal combustion engines have undergone technological developments that can be fueled by various types of fuels in different mixture proportions. To achieve this, a detailed study of the main factors that influence the engine combustion process is necessary. The objective of this study is to evaluate the effects of varying the ignition advance on the performance parameters and vibration level of the engine operated with regular gasoline, podium gasoline, ethanol and a mixture of ethanol with regular gasoline. The experimental tests consisted of operating an Otto cycle engine on a bench dynamometer under full load conditions, varying rotation and ignition advance by 5, 10 and 20% in relation to the original ignition advance and correlating the levels of pre-ignition, knock, engine vibration levels with engine performance parameters. The results showed that the engine vibration level was influenced by the type of fuel used, engine performance parameters and the presence of pre-ignition and knock. The results also confirmed that fuels with a higher-octane number supported greater ignition advances, presenting lower levels of pre-ignition, knock and vibration in the engine. In all operating conditions, the level of engine vibration, presence of pre-ignition and knock was higher when using regular gasoline, followed by a mixture of ethanol and regular gasoline. This study is relevant because it correlates the vibration level of an internal combustion engine with the type of fuel and the engine's combustion process.