Hur enkel- & dubbelportsturbin i kombination med två olika avgassamlare påverkar gasväxlingsprestanda på en Scania V8

Sammanfattning: The exhaust arrangement on a Scania V8 consists of one manifold at each bank connected to a twin entry turbine (8-2-2). A study in GT-Power has shown improved performance and reduced cylinder to cylinder variations using two manifolds at each bank in combination with a single entry turbine (8-4-1). This thesis work analyses the difference in performance shown in simulation and verify it by engine test. The initial work was focused on simulation in GT-Power. Investigating how exhaust manifold volume and pulses effects the turbine efficiency and the mean effective pressure during the gas exchange. To verify GT-Power simulations four engine tests with different exhaust arrangement have been made. The results from GT-Power simulation indicate that a larger exhaust volume improve the turbine efficiency. Also an even flow of pulses to the turbine entry is positive for the efficiency. In engine test a single entry turbine has 4 % higher efficiency than a twin entry, this result correlate well to simulations. The smaller volume in the 8-2 manifold effects the turbine efficiency positive at 1200 rpm because of less energy losses in this manifold. The 8-4-1 manifold show in test up to 400 mbar higher mean effective pressure during the gas exchange than the 8-2-2 manifold. In simulation the difference were 600 mbar. In Engine test the 8-4 manifold has 1 % higher volumetric efficiency and about 30° Clower exhaust temperature than the 8-2 manifold. The tendencies from simulation checks well with engine test results, especially at 1500 and 1900 rpm. The difference in mean effective pressure in the gas exchange and the cylinder to cylinder variations is not that big in test as in simulation. This is not due to turbine efficiency rather pulse transfer between the cylinder banks. The engine test shows that two manifolds per cylinder bank in combination with a single entry turbine, 8-4-1, has the lowest cylinder to cylinder variations and the best gas exchange performance. Because of this is the 8-4-1 system the best for the V8 engine.