Computational Investigations On The Effect of Start of Combustion Timing on The Perfor-mance and Emissions Characteristics Of A Four Cylinder Four Stroke Cycle Spark Ignition En-gine With Hydrogen Direct Injection And GDI Modes

This paper presents the results of the computational research investigations on a 4-stroke 4- cylinder spark ignition engine fitted with direct fuel injection system with hydrogen and gasoline as two alternative fuels. The simulated results were generated in the professional internal combus-tion engines software named as AVL BOOST. The software has a graphical user interface for modeling the complete engine system using various elements provided in its design. The software basically uses the conservation laws of mass, momentum and energy in its design codes. Further the software has the facility of using alternative thermodynamic models for combustion, heat transfer and frictional power etc.

First a GDI engine was modeled from the basic elements. The GDI engine was run under constant speed, constant air-fuel ratio and variable start of combustion timing operation. The results were generated for the engine performance and its emissions characteristics. The proce-dure was repeated by operating the engine with hydrogen as an alternative fuel under similar design and operating conditions. Again the results were generated its performance and emissions characteristics. The results showed that the power and the torque output of the hydrogen based spark ignition engine fitted with direct fuel injection system were higher than that of its corresponding GDI version. Also the hydrogen version of the direct fuel injection type of spark ignition engine consumes lesser quantity of fuel per unit of energy output as compared to its gasoline version. Further the hydrogen based engine does not produce any CO emissions. Moreover the soot and NOx emissions produced by the hydrogen based direct injection spark ignition engine were lower than those produced by its GDI version.