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This work experimentally investigates how the dwell time between pilot injection and main injection influences combustion characteristics and emissions (NOx, CO, THC and Smoke) in a single-cylinder DI diesel engine. Additionally, results from diesel injection are compared with those shown in dimethyl ether (DME) injection under the identical injection strategy to demonstrate the sensitivity of the combustion characteristics and emissions to changes of the fuel type. Two fuel injection systems are applied for this experiment due to the differences of fuel characteristic with regard to physical and chemical properties. The injection strategy is accomplished by varying the dwell time (10°CA, 16°CA and 22°CA) between injections at five main injection timings (-4°CA aTDC, -2°CA aTDC, TDC, 2°CA aTDC and 4°CA aTDC). It was found that pilot injection offers good potential to lower the heat-release rate with reduced pressure traces regardless of the dwell time between injections and fuel type.