Internal Combustion Engine Essay

Internal combustion engines have been a relatively inexpensive and reliable source of power for applications ranging from domestic use to large scale industrial and transportation sectors for most of the twentieth century. DI Diesel engines, having the evident benefit of a higher thermal efficiency than all other engines, have served for both light- duty and heavy-duty vehicles. The in-cylinder fluid motion in internal combustion engines is one of the most important factors controlling the combustion process. It governs the fuel-air mixing and burning rates in diesel engines. The fluid flow prior to combustion in internal combustion engines is generated during the induction process and developed during the compression stroke. Therefore, a better

But when the piston moves towards Top Dead Centre (TDC), the bowl geometry has a significant effect on air flow for creating proper turbulence thereby resulting better mixing and better combustion. Turbulence plays a vital role in combustion phenomenon. In combustion the flame speed is very low in non-turbulent mixtures. A turbulent motion of the mixture intensifies the processes of heat transfer and mixing of the burned and unburned portions in the flame front, which practically increase in proportion to the turbulence velocity. This turbulence can be increased at the end of the compression by suitable design of combustion chamber, which involves the geometry of cylinder head and piston crown. The degree of turbulence increases directly with the piston speed. However, excessive turbulence is also undesirable. The effects of turbulence can be summarized as, turbulence accelerates chemical action so that the combustion time is reduced and hence minimizes the tendency to detonate. Turbulence increases the heat flow to the cylinder wall and in the limit excessive turbulence may extinguish the