Comparing the operation of an HSDI engine using multiple injection schemes with soybean biodiesel, diesel and their blends

The KIVA-3V code, developed by Los Alamos National Laboratory, with modifications that improve its capability with biodiesel simulations was used to model the operation of an HSDI engine using blends of soybean biodiesel and diesel. Biodiesel and their blends with diesel are frequently used to reduce emissions from diesel engines, although previous studies showed that biodiesel may increase NO_x emission. The paradox may be resolved by running the engine in low temperature combustion mode with biodiesel/diesel blends, as low temperature combustion simultaneously reduced NO_x and soot. The modified KIVA code predicts the major combustion characteristics: peak combustion pressure, heat release rate and ignition timing accurately when compared with experimental measurements. It also correctly predicts the trend of NO_x emissions. It was observed that the cylinder temperature distribution has a strong effect on emission levels. The combustion process, engine performance and emissions are conventional with conventional and low temperature combustion injection schemes.