A theoretical and an experimental investigation of a small scale trigeneration based on a diesel engine generator set is conducted. Comparing with the separate generation system, trigeneration saves primary energy input; and it reduces CO 2 gas emission to the environment. A conclusion can be drawn that trigeneration is an environment friendly method, and it is financially feasible.

An experimental investigation of NOx emission reduction from automotive (petrol) engine using the Miller Cycle was carried out. Two versions of Miller Cycle were designed and realized on a petrol engine. The tests were carried out on the test rig. The test results showed that applying Miller Cycle could reduce the emission of nitrogen oxides from petrol engine.

Experimental tests have been carried out to evaluate the performance and emissions characteristics of a diesel engine when fuelled by blends of 25% vegetable oil with 75% diesel fuel, 50% vegetable oil with 50% diesel fuel, 75% vegetable oil with 25% diesel fuel, and 100% vegetable oil, compared with the performance, emissions characteristics of 100% diesel fuel. The series of tests were conducted and repeated six times using each of the test fuels. 100% of ordinary diesel fuel was also used for comparison purposes. The engine worked at a fixed speed of 1500 r/min, but at different loads respectively, i.e. 0%, 25%, 50%, 75% and 100% of the engine load. The performance and the emission characteristics of exhaust gases of the engine were compared and analyzed. The experimental results showed that the carbon monoxide (CO) emission from the vegetable oil and vegetable oil/diesel fuel blends were nearly all higher than that from pure diesel fuel at the engine 0% load to 75% load. Only at the 100% engine load point, the CO emission of vegetable oil and vegetable oil/diesel fuel blends was lower than that of diesel fuel. The hydrocarbon (HC) emission of vegetable oil and vegetable/diesel fuel blends were lower than that of diesel fuel, except that 50% of vegetable oil and 50% diesel fuel blend was a little higher than that of diesel fuel. The oxides of nitrogen (NOx) emission of vegetable oil and vegetable oil/diesel fuel blends, at the range of tests, were lower than that of diesel fuel.