Exhaust System Design Improvement of Internal Combustion Engine

• Main Authors: Yu-Feng Lin, 林裕豐
• Other Authors: 吳浴沂
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/g496q9

碩士 === 國立臺北科技大學 === 車輛工程系所 === 98 === This paper is focus on exhaust system performance improvement. To design a new exhaust system which has to keep several design limitation. 1st one is set catalyst position closer to cylinder head. 2nd is satisfy engine room space limitation. 3rd is satisfy catalyst flow uniformity index equal to 0.85 or more. 4th is keeping engine performance compares with base engine. This paper includes 2 steps, one is 3d model design step and the other is simulation step. 3D design step: Following the exhaust system layout limitation, choosing 4-2-1#1 exhaust concept to design new exhaust system. For new concept exhaust system has been created which has new catalyst position 44.9mm closer to the cylinder head than base engine. And following new flow distribution concept to change exhaust flow angle between end of manifold and catalyst front end to increase distribution area of flow into catalyst. Simulation step: - Computational Fluid Dynamics: Each cylinder was simulated in steady state condition to calculate flow uniformity (γ) on section of catalyst. Result of flow uniformity will be a index of catalyst utilization. For the final result of uniformity shows that new concept exhaust system is better the traditional one and satisfies 0.85 requirement。 - Performance simulation: Performance of engine simulation model which using new exhaust system has max. power (75.98ps@6000rpm) and max. torque (104.08N.m@4500rpm). To compare with performance of base engine simulation model and real engine test. It shows that difference of overall performance is in 1.5% which satisfies performance requirement. Follow each result of 2 steps above; the new concept exhaust manifold can keep performance in position of catalyst 44.9mm closer to cylinder head condition, and satisfies uniformity index which should improve exhaust system performance of base engine.