Laboratory endurance test of a sunflower oil blend in a diesel engine

The effects of using a 25/75 blend (v/v) of alkali refined sunflower oil and diesel fuel in a direct-injection diesel engine were compared to a baseline test with diesel fuel. There were no significant problems with engine operation during the baseline test. However, problems were experienced while using the blended fuel. The major problems were (a) abnormal buildup on the injection nozzle-tips, (b) injector needle sticking, (c) secondary injection, (d) carbon buildup in the intake ports, (e) carbon deposits on the exhaust valve stems, (f) carbon filling of the compression ring grooves, and (g) abnormal lacquer and varnish buildup on the third piston land. The 25.75 blend cannot be recommended for long-term use in a direct-injection engine.