EXPERIMENTAL INVESTIGATION AND CFD ANALYSIS OF A MULTI-CYLINDER FOUR STROKE SI ENGINE EXHAUST MANIFOLD FOR OPTIMAL GEOMETRY TO REDUCE BACKPRESSURE AND TO IMPROVE FUEL EFFICIENCY

In internal combustion engines, exhaust manifold plays a vital role in the improvement of fuel consumption of the engine. A good conditioned exhaust manifold increases the performance of the engine. The work is focused on improving the fuel consumption, by reducing the backpressure in the exhaust manifold, experimentally and computationally. This work comprehensively analyzes eight different models of exhaust manifold and concluded the best possible design for least fuel consumption. CFD is the current trend on automotive field in reducing the cost effect for analysis of various models on the basis of fluid flow. A multi-cylinder Maruti - Suzuki Wagon-R engine with maximum speed of 1500 rpm is taken for the analysis. The load and performance test is conducted. From the experiment backpressure and exhaust temperatures are measured. The mass flow rate and velocities are calculated. Flow through the exhaust manifold is analyzed using commercially available software with mass flow rate and pressure as boundary conditions. The results obtained by CFD are compared with experimental values and found to be closely matching. For comparison, experimental and computational values of backpressure and exhaust velocity are plotted against corresponding experimental values at all loading conditions. The decrease in backpressure and increase in velocities are shown using pressure contour and velocity contour.