An experimental evaluation of hydrogen, biodiesel and butanol blends on performance, combustion and exhaust characteristics in a diesel engine

High levels of engine-out emissions contribute to environmental pollution, which triggers global warming. In this respect, the utilization of environmentally friendly fuels is considered a viable option in internal combustion engines. In this study, the effects of biodiesel, butanol, and H2 fuels, which could serve as alternatives to fossil-based diesel fuel, on engine performance, combustion, and exhaust emissions are examined in a four-stroke, four-cylinder diesel engine with common rail injection system. With the increase in the H2 ratio in the energy share, an increase in brake specific energy consumption and a decrease in brake specific fuel consumption were observed. In tests conducted at high H2 ratios, not only did the cylinder gas pressure exceed 100 bar and the cylinder gas temperature exceed 2000 K, but also an increase of more than 50% was also observed in the maximum pressure increase rate. In addition, the maximum NO emission was obtained as 9.2 g/kWh in B30 + 70H2 tests. The replacement of biodiesel with diesel generally caused an increase in HC, NO, and CO2 emissions. With the addition of butanol, a reduction in emissions was observed based on test results conducted with pure biodiesel.