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The higher portion of biodiesel blended fuel will result in lower power output since biodiesel itself has lower energy input (B20 gave about 3% lower torque output at peak torque speed). In the ELR (Engine Load Response) Test Cycle, biodiesel blended fuel emitted less smoke than diesel fuel, while CO and NOx emission of biodiesel blended fuel and diesel fuel are comparable. Biodiesel particulate matter (PM) seemed to be higher than diesel fuel. In addition, additized biodiesel blended fuels (B5, B10 and B20) proved qualitative in oxidation stability, acid value, etc. Biodiesel specific lubricant confirmed its functions by evaluating the viscosity increase, fuel dilution, TAN, TBN and wear metal content during engine durability test. The used oil analysis affirmed that the lubricant could effectively be used with particular biodiesel blended fuel in advanced, heavy-duty common-rail DI diesel engines.

Reduction of oil consumption of engines is required to avoid a negative effect on engine after treatment devices. Engines are required fuel economy for reduction of carbon-dioxide emission, and it is known that reduction of piston frictions is effective on fuel economy. However friction reduction of pistons sometimes causes an increase in engine oil consumption. Therefore reduction of engine oil consumption becomes important subject recently. The ultimate goal of this study is developing the estimation method of oil consumption, and the mechanism of oil upward transport at oil ring gap was investigated in this paper. Oil pressure under the oil ring lower rail was measured by newly developed apparatus. It was found that the piston slap motion and piston up and down motion affected oil pressure rise under the oil ring and oil was spouted through ring-gap by the pressure. The effect of the piston design on the oil pressure generation was also investigated.