Single Cylinder ICE Exhaust Optimization

Abstract: In this thesis, a study of an exhaust system on a single cylinder internal combustion engine was performed at AVL in Södertälje, from September 2011 to January 2012.
AVL works with engine and drivetrain development and is involved in the whole chain of development, from simulation to construction of hardware and at the end tools for testing, measuring and certification.
The single cylinder engine is used for tests and research due to its simple construction. AVL´s single cylinder (SC) engine is a hybrid based on an LNF (SAAB/GM engine family) head with a long stroke crankshaft and a displacement of 550cc, which would result in a 2.2 liter four cylinder engine. The LNF is a turbocharged, direct or port fuel injected 4-stroke, with dual overhead camshafts and four valves internal combustion engine. AVL needed an optimized exhaust system for this engine. Cylinder and exhaust pressure during the exhaust stroke where subjects of focus as the initial pressure oscillated round the average exhaust pressure level.
Measurements were made on the engine for all the necessary data for comparison and calibration of the simulated GT-Power model. GT-Post was used for analysis and displaying data and graphs.
Remodeling of the computer models exhaust system was performed in Gem 3D, a 3-dimensional pipe analysis submissive program to GT-Power. Simulations showed that the solution for the pulse oscillations were to use a perforated pipe inside a wool filled box.
The finished product was modeled in NX and constructed to fit the test bed. The new exhaust system was also made easier to assemble and maintain in the SC engine test bed. The new exhaust system/pulse damper was tested and verified. The cylinder pressure during the exhaust stroke did not meet the simulations behavior, but the pressure waves in the exhaust system were reduced. In conclusion, suggestions were made of what future work can consist of in order to improve the performance of the created pulse damper.