Vegetable oil usage in a diesel engine that its piston and valves coated with ZrO2

Alternative fuel researches are being carried out due to the increasing energy requirement and near future petroleum depletion. One of the most important alternative fuel researches is considered to be vegetable oil usage in internal combustion engines. In this study, three pure vegetable oils were used in a diesel engine. Soybean oil, tobacco seed oil and almond seed oil were blended with diesel fuel by volumes of 15%, 35% and 65% rates, volumetrically. The mentioned blend fuels and standard diesel fuel were then used in e single cylinder, four strokes and air cooled diesel engine. Then the engine was converted to a low heat rejection diesel engine. The piston head and exhaust and intake valves of the engine were coated with ZrO2 coating ceramic material. Then the above mentioned test fuels were tested in the coating engine. The tests results of coating and uncoated normal engine operation were compared with each other. In the performance tests, engine torque, power and brake specific fuel consumption results for test fuels usage in were observed. In the emission test, CO,CO2, HC and NOx emission results for all the test fuels operation were founded and compared with the standard diesel fuel operation. Results of performance have showed that the performance of the engine was slightly decreased with vegetable oil usage. However, the performance parameters of all the vegetable oils were increased when the test engine was coated probably due to the reduction of heat transfer through the engine cylinder. As for the emission results, both for coated and uncoated engine operation CO and HC emissions were decreased with vegetable oil usage. However, NOx emissions were increased for both engine coating and vegetable oil usage in diesel engine. Keywords: Diesel engine, Performance and emission, Soybean oil, Almond oil, Tobacco oil.