An investigation on the performance of a Brayton cycle waste heat recovery system for turbocharged diesel engines

A Brayton cycle waste heat recovery (WHR) system for turbocharged diesel engines was proposed and the performance of a diesel engine integrated with the proposed system was investigated. The waste heat recovery system is integrated with the turbocharging system of diesel engines, using the turbocharger compressor as the Brayton cycle compressor. The engine cycle simulation code GT-Suite 7.0 was used to investigate the performance of a diesel engine integrated with the WHR system. A Brayton cycle turbine was designed and its performance was simulated with a through-flow model. The turbocharging system of the original engine was modified and the energy flow distribution between the diesel cycle and the Brayton cycle was optimized. Results show that the fuel economy of the diesel engine can be improved by 2.6% at high engine speed and 4.6% at low engine speed under engine full load operating conditions when equipped with the Brayton cycle WHR system. The influence of turbocharger parameters on the WHR engine performance was invesgated.