A Second Law Approach to Exhaust System Optimization

A model has been constructed that applies second law analysis to a Fanno formulation of the exhaust process of a turbocharged diesel engine. The model has been used to quantify available energy destruction at the valve and in the manifold and to study the influence of various system parameters on the relative magnitude of these exhaust system losses.

The model formulation and its application to the optimization of the exhaust manifold diameter is discussed. Data are then presented which address the influence of the manifold friction, turbine efficiency, turbine power extraction, valve flow area, compression ratio, speed, load and air-fuel ratio on the available energy destruction in the exhaust system.