In this chapter, as an alternative to conventional engines, compressed biogas (CBG)-fueled compression ignition (CI) engine was evaluated. Biogas fuel is considerably economic due to the local product fuel compared to that of CNG and LPG fuels for many countries. In addition, due to the higher octane rate, biogas is considerably adaptable for the diesel engines. In this issue, CBG diesel-fueled engine was investigated using full geometry 3D computational fluid dynamics (CFD) simulations including intake and exhaust ports were used in optimization process to get the optimum design parameters of the CBG-diesel engine. Usage of CBG fuel in the optimized CBG engine without any constructive change in cylinder block will considerably decrease the cost. During the engine design, one-dimensional (1D) and three-dimensional (3D) CFD codes and multi-objective optimization code were employed by coupling codes. CBG and diesel fuels were defined as leading reactants using user-defined code in dual-fuel diesel engine modeling. CBG and diesel mass flow rates, start of pilot diesel fuel injection, compression ratio, valve timing, and engine speed were defined as input variables in different engine loads and evaluated about 20,000 cases to define the proper operating conditions. CBG-diesel engine and significantly lower NOx emissions were emitted under dual-fuel operation for all cases compared to single-fuel mode at all engine load conditions. Moreover, CBG-diesel engine provided superior performance in reductions of NOx and particulate matter (PM) emissions.
Part of the book: Diesel and Gasoline Engines