Abstract:

The effect of transmission ratio between power turbine and diesel engine crank power on the
performances and the fuel economy was investigated for the application of turbo-compound system with Variable
Geometry Turbocharger (VGT) on a heavy duty diesel engine. A one-dimensional model was established to
simulate the turbo-compound engine and optimize the matching of the power turbine and turbocharger with the
engine. A turbo-compound prototype diesel engine was developed based on a conventional 11-L heavy-duty
diesel engine, and then tested to investigate the impacts of the openness of the VGT on the turbo-compound
engine performances, and to fine the most optimal control strategy. The results show that the turbo-compound
engine is better than the original machine under engine full load operation conditions. The brake specific fuel
consumption (BSFC) increases 3% on average with a maximum BSFC of 8%. Therefore, turbo-compounding
is a key technology to satisfy the future requirements of diesel engine’s energy conservation and emission
reduction.

Key words: heavy-duty diesel engine, turbo-compound, variable geometry turbocharger (VGT), fuel economy, brake specific fuel consumption (BSFC)