International Journal of Engineering Technology, Management and Applied Sciences www.ijetmas.com March 2015, Volume 3 Special Issue, ISSN 2349-4476 234 Sachin Singla, Sumeet Sharma, Dr. D. Gangacharyulu Study of Design Improvement of Intake Manifold of Internal Combustion Engine Sachin Singla Student Mechanical Engg. Department Thapar University, Patiala Mr. Sumeet Sharma Associate Professor Mechanical Engg. Department Thapar University, Patiala Dr. D. Gangacharyulu Professor Chemical Engg. Department Thapar University, Patiala ABSTRACT: For a better performance of an internal combustion engine, design of intake manifold is one of the important factor. It is required that equal mass of air fuel mixture is delivered to each cylinder of the engine. Unequal distribution of charge reduces the efficiency of the engine. Presented study aims at the design modification of the intake manifold so that almost equal velocity can be obtained at the end of each runner. For the study purpose Intake manifold of Maruti Wagnor was used. Experimental study was conducted on the manifold and variation in outlet velocity and outlet pressure was recorded at different inlet velocities. Further, three dimensional drawing of the intake manifold was made and CFD simulation was conducted using ANSYS FLUENT. Two models were studied by making some modifications in the actual manifold and thus an improved manifold design was suggested. Results show that nearly equal velocity was obtained at all the runner outlet and flow velocity at outlet 1 increased by 16%, and velocity in other outlets improved by approximately 5% to 7% as compared to actual model. Keywords: Intake Manifold, Computational Fluid Dynamics (CFD) 1. INTRODUCTION: In an automobile, engine is one of the main component. Continuous research is going to make the engine more and more efficient and use of alternate fuels. The major challenge faced is to reduce the global carbon emission and to reduce the oil consumption. Now a day compressed natural gas (CNG) is widely used in the automobiles. Efficiency of an engine working on CNG is very less. When compared to the gasoline, it is seen that the average torque and power losses of CNG is in range of 1.6 to 21.6% and 3 to 19.7% respectively [1]. The efficiency of an engine depends on many factors, design of intake manifold (IM) being one of them. The function of the IM is even distribution of a uniform mixture of fuel and air to all the cylinders. Even distribution is essential for a better performance and optimal efficiency. Design of the IM is thus very important for better engine performance. Length of the runner, diameter of the runner, plenum volume, smoothness of the joints, shape of the runners are the some of the factors which are considered during the design of the IM. Computational Fluid Dynamics (CFD) is very helpful in predicting the flow pattern inside the cylinder and the IM. Using the CFD can reduce the design modification time. To analyze the physical phenomena which is involved in change of kinetic energy, renormalization group theory (RNG k- ε) turbulent model is used [2]. For an automobile different IM are used as per requirement and then the modifications are done as needed. But some general modifications are preferred for a good IM design. For the IM of a diesel engine, profile near the corners are made smooth so that reflecting shock waves at high velocity can be avoided. Some improvements in the plenum can also be made so that the flow can be easily directed into the runners [3]. With increase in the plenum