Geometry design and optimization of piston by using finite element method

The piston performance may be impacted by piston geometry, stress, temperature and deformation applied. Thus, the purpose of this study is to investigate the changes of piston performance with different piston head designs. Besides, the piston is optimized by using topology optimization to remove excessive material. The study was carried out by using the dimension of a piston based on the cylinder of a spark ignition engine. The four piston head designs are flat-top piston, bowl piston, square bowl piston and dome piston. All four piston designs were modelled by using Solidworks. Static Structural and Steady State Thermal Analysis in ANSYS Workbench were used to analyze the piston performance. The measured parameters are stress, deformation and temperature distribution. Next, optimization of piston was done by using topology optimization to identify non-essential parts that can be removed. The optimized piston design was analyzed. The findings for the original and optimized piston geometries were tabulated to make comparison. It is found that bowl piston has lower stress, deformation and temperature. The stress, deformation and temperature of optimized piston is lower than original piston. The mass of optimized piston is about 5 percent lesser than the original piston.

Numerical Investigation of the Impact of Spray – Bowl Interaction on Thermal Efficiency of a Gasoline Compression Ignition Engine

Gasoline compression ignition (GCI) is a promising way to achieve high thermal efficiency and low emissions while leveraging conventional diesel engine hardware. GCI is a partially premixed combustion concept, which derives its superiority from good volatility and long ignition delay of gasoline-like fuels. The present study investigates the interaction between the piston bowl and the spray plume of a compression ignition engine that operates with a late fuel injection strategy using computational fluid dynamics (CFD) analysis. Simulations were carried out on a single cylinder of a multi-cylinder heavy-duty compression ignition engine. The engine operates at a speed of 1038 rev/min., and a compression ratio of 17. Incylinder turbulence was modelled using RNG k-ε model and the fuel spray break up was modelled using KH-RT model. A reduced chemical kinetic mechanism was used to model combustion chemistry. After validating the combustion and performance characteristics of the baseline piston against experimental results, several new piston bowl designs were generated using CAESES. Full cycle engine simulations for four selected bowl profiles were carried out. The results compare the spray-bowl interaction of the new piston bowl designs with the baseline design. It was found that the lip location and center depth of the bowl profile are the critical design parameters that influence the air utilization and heat transfer losses. The impact of spray-bowl interaction on thermal efficiency of the engine is investigated.