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With the upcoming stringent norms for diesel engines and continual pursuit for more and more fuel-efficient engines, it is necessary to enhance air-fuel mixing for proper combustion. The design of inlet port plays an important role in the engine performance, because the air-fuel mixing depends upon the air turbulence. Research showed that helical type inlet-port will be ideal for the engine with nominal injection pressure value less than 800-bar and thermodynamic simulation results highlighted the need of an optimum swirl number for the specimen engine. A parametric study on inlet port design has been done to achieve the optimum flow capacity.

The rate of wear of valve seats on the valve and in the cylinder head is mainly a function of the seat load and the total relative displacement velocity after seating. The problem of wear becomes severer when the valve head deflects under large firing pressures observed in modern high bmep engines. A model relating the wear rate linearly with the product of load and the relative displacement at the seat is developed. After the valve closes, superficial delamination occurs when the shear strain due to friction at the surface exceeds the plasticity limit of material. The wear is minimised by reducing the co-efficient of friction at the interface or by reducing the relative displacement. The model was validated by accelerated experiments on an actual engine running at an 18-bar bmep. Finite element analysis of the valve and the seat showed that the displacement of the valve seat could be linearly correlated with the deflection of the valve at the center.