Performance and Emissions of a CRDI Passenger Van Using CME-Diesel Blends

In a move to reduce dependence on imported fossil fuels, develop and utilize indigenous renewable and sustainably-sourced clean energy sources, the Philippines enacted the Biofuels Act of 2006 (or Republic Act 9367) that mandated blending of biodiesel with commercially sold diesel fuels which presently is at 2% coconut methyl ester (CME) by volume. Deliberations are underway to shift to 5% by volume so that data on the effects on performance and emissions of percentage blends are necessary. This study presents fuel consumption and emissions measurements of an in-use passenger van with a common-rail direct injection (CRDI) powertrain fueled with 2, 5, 10, & 20 percent CME-diesel blends by volume (designated as B2, B5, B10, & B20 respectively) driven on the Japanese 10–15 Mode drive cycle. Results indicate B2-B20 had only a marginal effect on heating values, fuel blend density, and maximum power. Relative to neat diesel, the blends showed a 1–5% lower specific fuel consumption (SFC) with B5 lowest. Mileage was 1–5% higher with the blends with B5 highest. CO decreased with increasing blend. THC emissions of B1-B20 were roughly half that of diesel. NOx from the CME blends was marginally lower than diesel. The CO and THC trends agreed with published literature and usually ascribed to overall lean mixtures and increased amount of oxygenated fuel at higher CME blends. The NOx results need further investigation as it seemed to contradict other studies. Based on these results, B5 yielded the best combination of fuel economy and emissions improvement over neat diesel and B2 without performance loss.