Effect Of Thermal Load On Valve By Using Conventional Diesel And Blended Fuels

Abstract

The valves used in the IC engines are of three types: Poppet or mushroom valve or Sleeve valve or Rotary valve. Of these three types, Poppet valve is most commonly used. Since both the inlet and exhaust valves are subjected to high temperatures of 500°C to 1200°C during the power stroke, therefore, it is necessary that the materials of the valves should withstand these temperatures. The temperature at the inlet valve is less compared to exhaust valve. Thus the inlet valve is generally made of nickel chromium alloy steel and exhaust valve is made of si-chrome steel.Automobile engines are usually petrol, diesel or gasoline engines. Petrol engines are Spark Ignition engines and diesel engines are Compression Ignition engines. Blended fuels are mixtures of traditional and alternative fuels in varying percentages. Here the effect of diesel blended fuels on valve is studied by mathematical correlations applying thermal loads produced during combustion. Blended fuels are usually bio fuels blended in different percentages. Percentages vary from 0%, 5%, 10% and 20%.Internal combustion engines produce exhaust gases at extremely high temperatures and pressures. As these hot gases pass through the exhaust valve, temperatures of the valve, valve seat, and stem increase. To avoid any damage to the exhaust valve assembly, heat is transferred from the exhaust valve through different parts, especially the valve seat insert during the opening and closing cycle as they come into contact with each other. In this thesis, a finite-element method is used for modeling the thermal analysis of an exhaust valve. The temperature distribution and resultant thermal fluxes are evaluated. Detailed analyses are performed to estimate the boundary conditions of an internal combustion engine. In this thesis, Catia is employed for modeling and Ansys is used for analysis of the exhaust valve.