Simulated Experimental Study on Variable Geometry Exhaust Manifold Turbocharging System

The effect of the variable geometry exhaust manifold turbocharging system used in six-cylinder diesel engine was investigated.The controlled valve opened and closed modes were represented respectively by using the original exhaust manifold and the newly made exhaust manifold of semi-constant pressure.The experimental results indicate that the specific fuel consumption(SFC) of semi-constant pressure turbocharging mode reduces by 4.7 g/(kW·h) than pulse turbocharging mode in rated conditions.It is learnt from further analysis that in the semi-constant pressure turbocharging mode the SFC reduction is caused by less negative pumping work,and it in turn is attributed to the reduced average pressure in the exhaust manifold during forced exhaust.