Design of an Exhaust Gas Energy Recovery System for Internal Combustion Engines

The current research paper presents the experimental findings following exhaust runner heat exchanger tests as well as a realistic theoretical proof of concept for steam turbocharging by using said results. A preliminary heat analysis was completed in order to first assess the magnitude of recoverable energy from the spent exhaust gases. Through experimentation, actual heat absorbed by the water was successfully obtained and was higher than predicted. The proof of concept was then completed by inputting the experimental engine parameters into a turbocharged Otto cycle combined to a Rankine cycle using experimental figures for the heat input stages of the assessment. The theory ultimately resulted in peak improvements of 7.446% in engine thermal efficiency and an interesting reduction in brake specific fuel consumption of 6.930% near 2500 RPM. Furthermore, through the use of steam turbocharging, brake engine power can theoretically be improved by 35.00%, resulting in a 13.73% increase in the current experimental engine’s power density. The test engine was mounted onto a hydraulic engine dyno and a baseline of its power and torque output was recorded for final confirmation that the heat recuperated via this energy recovery system was not being negated elsewhere in the combined cycle. Finally, a preliminary steam turbine was designed and the optimal system configuration was presented for future use. The obtained results clearly demonstrate that steam turbocharging is a novel energy recovery system with great potential