Search Results

The detailed chemical reactions leading to autoignition of n-pentane are investigated in this study. A single-cylinder engine operating in a nonfired mode was used. The engine is supercharged and the temperature of the inlet fuel/air mixture is varied. By increasing the inlet manifold temperature, at a given inlet manifold pressure, the fuel/air mixture can be made to undergo autoignition. In-cylinder pressure and temperature profiles were measured. Gas samples from the combustion chamber were extracted and analyzed using gas chromatography techniques. The detailed chemical reaction mechanisms explaining the products from the different stages of the fuel oxidation process are presented. It is speculated that the generation of OH radicals from the peroxide (QOOH) decomposition is responsible for the autoignition of the n-pentane fuel/air mixture.

Recently, studies were conducted on a single cylinder, four stroke engine to investigate the effect of temperature and local mixedness on exhaust port hydrocarbon oxidation. To examine the effect of temperature, hydrocarbon tracers (propane, propene, 1-butene, n-butane, and n-pentane) were individually injected into the exhaust port just behind the exhaust valve for operating conditions that provided different exhaust port temperatures. For the local mixedness experiments, tracer mixtures (propane + n-butane, 1-butene + n-butane, propene + n-butane) were injected into the exhaust port just behind either a normal exhaust valve or a shrouded exhaust valve. The concentration of tracers and their reaction products were measured using gas chromatography of samples withdrawn from the exhaust stream. The tracer consumption behavior with changing port temperature confirmed that there is a minimum port temperature for hydrocarbon oxidation.