Experimental Investigation on Combustion and Performance Characteristics of a Direct-Injection Diesel Engine

In present experimental study, combustion characteristics and performance parameters of a multi cylinder four stroke direct injection diesel engine are investigated. Different combustion characteristics like peak cylinder pressure, net heat release, rate of pressure rise, cumulative heat release, mean exhaust gas temperature are analyzed at various loads and at constant speed of 1500 rpm. Effect of combustion characteristics on performance parameters like thermal efficiency and brake specific fuel consumption are also studied. It is found that various combustion characteristics increase non-linearly with increasing engine load and this is attributed to the more fuel requirement at higher loads. Performance parameters are significantly affected by engine load and are found to be enhanced by increasing loads. Highest thermal efficiency (nearly 25%), lowest brake specific fuel consumption (0.38 kg/kWh) and lowest ignition delay period (nearly 0.41 ms or 0.4 crank angle) are obtained at 9 kg load. It is infer that at higher loads, engine performance improves due to better ignition and combustion characteristics which subsequently result in lower exhaust emissions.