The present work is based on the need for understanding the in-cylinder flow and its subsequent effects on combustion in a valved-two-stroke spark ignition engine with fuel injection using Computational Fluid Dynamics (CFD) and experimental techniques. In this context, the CFD code KIVA-II has been modified to model the two-stroke engine gas exchange and combustion processes. A 3-D Cartesian grid generation program for complex engine geometry has been added to the KIVA code which has been modified to include intake and exhaust flow processes with valves. New and improved sub models for wall jet interaction, mixing controlled combustion and one dimensional wave action have also been incorporated. The modified version of the program has been used to simulate a fuel injected two-stroke spark ignition engine and parametric studies have been undertaken. The simulated flow, combustion and exhaust emission characteristics over a wide range of operating conditions show the expected trends in behaviour observed in actual engines. In the second phase of this study, the air-assisted-fuel-injection (AAFI) process into a cylinder has been simulated with a high resolution computational grid. The simulation results are presented and compared with experimental data obtained using the Schlieren optical technique. An approximate method based on the conservation of mass, momentum and energy of the spray jet and using a comparatively coarse grid has been suggested for simulating the AAFI process. The simulation study predicts a high degree of atomisation of fuel spray with Sauter mean diameter around 10 μm even with moderate air and fuel pressures. The penetration and width of spray are simulated within 15% of the experimental values. In the last phase of this study, the flow and combustion processes have been studied for a four-stroke spark ignition engine with the AAFI process. The simulation results obtained using this approximate method have been validated with experimental data ge.

This project deals with the numerical setup about the effect of different mixture properties of premixed combustion material using Computational Fluid Dynamic (CFD). Mitsubishi Magma 4G15 is used as the base line engine design for the simulation model. 2000 revolution per minute (rpm) and 1000 iterations are set as the tested speed and the number of iterations per time step respectively. The simulation is started right before the spark ignited and when both valves are closed. The model is simulated at different mixture properties which are constant and varying mixture properties. The constant mixture properties value is taken from previous study. While the varying mixture properties is simulated using kinetic theory where only specific heat, thermal conductivity, and viscosity are varied. Case 1 is set as the constant mixture properties and also as the benchmark case. Case 2 until case 5 is the varying mixture properties with different value of L-J parameters. Case 1 gives only 2.19% of deviation from the experimental result on the peak pressure value and 25% deviation on the peak pressure timing. Meanwhile, for case 2 until case 5, they give as much as 22.34% until 45% deviation on peak pressure value and 100% until 162.5% deviations on the peak pressure timing. The key parameter that caused the results are the L-J parameters, mass fraction burned, and turbulence flame speed. The inaccuracy of the turbulence speed is mostly based on laminar flame speed, thermal conductivity, and specific heat. So, the study of L-J parameter is needed to ensure the perfect result in using kinetic theory approach.

The 53 technical papers in this book show the improvements and design techniques that researchers have applied to performance and racing engines. They provide an insight into what the engineers consider to be the top improvements needed to advance engine technology; and cover subjects such as: 1) Direct injection; 2) Valve spring advancements; 3) Turbocharging; 4) Variable valve control; 5) Combustion evaluation; and 5) New racing engines.

1D and Multi-D Modeling Techniques for IC Engine Simulation provides a description of the most significant and recent achievements in the field of 1D engine simulation models and coupled 1D-3D modeling techniques, including 0D combustion models, quasi-3D methods and some 3D model applications.