HEAT REJECTION AVOIDANCE IN COMBUSTION ENGINES

Heat rejection to a cold reservoir is inherent of thermal machines operation. One of them, the engine cycle, aims to deliver liquid power and its efficiency increases directly proportional to the hot reservoir and inversely proportional to the cold reservoir. Most of the studies for increasing engine efficiency leads to increase the hot reservoir. This research instead, instigates the discussion of a better use of energy and heat rejection avoidance on internal some combustion engines systems. It demonstrates the principle that the heat rejection improvement using liquid instead of air ran against the real objective that should have been using it better. The paper shows feasible design steps with physical, energetic and economical approach to implement an engine gas recirculation system, which uses tail pipe gases, through a supersonic Laval nozzle parallel to intake line after charge air cooler. It also purposes waste heat recovery from engine liners as heat source for a Rankine cycle. All calculus and simulations are done based on a real engine data submitted to an European Transient Cycle.