Numerical Investigation of Diesel Engine Performance Under Different Fuel Mixed Modes

A thermodynamic numerical simulation model is developed to predict the performance of a direct injection four-stroke single cylinder diesel engine under different dual fuel modes. Diesel engine performance using neat diesel and blends of diesel with biogas, methane, and (biogas + hydrogen) in a dual fuel mode was investigated. The results were generated for a maximum energy substitution of biogas up to 70% and methane 70% with diesel 30% each. The simulated results of present study are found in good agreement with the published experimental results. The results obtained indicate that the combustion and performance characteristics are poor for (biogas + diesel) in dual fuel mode, however a small percentage of hydrogen addition in blend (biogas + diesel) significantly enhances their combustion and performance characteristics. Brake power and torque of blend DSL(20)BIO(60)H2(20) are comparable to neat diesel. As methane possesses better burning quality, it improves combustion characteristics and therefore methane blend DSL(40)CH4(60) produces higher brake power and torque than neat diesel. For maximum energy substitution, blends DSL(30)CH4(70) and DSL(30)BIO(50)H2(20) show highest brake thermal efficiency of nearly 39% and lowest brake specific energy consumption of about 15 MJ/kWh at an injection timing of 20 o BTDC. Injection timing of 20° BTDC gives maximum brake thermal efficiency as well as minimum brake specific energy consumption at different engine speeds for all fuel blends.