US9874130: IC-engine comprising a waste heat recovery system for compressing exhaust gases
This patent by Volvo trucks relates to an internal combustion engine arrangement that comprises an internal combustion reciprocating piston engine, and an exhaust line capable of collecting exhaust gases from said engine;a waste heat recovery system carrying a working fluid in a loop, in which said fluid is successively compressed, heated in a heat exchanger by means of the exhaust gases, and expanded in a first expander;a first compressor located in the exhaust line and mechanically connected to the first expander of the waste heat recovery system. The thermal energy of at least one engine fluid, such as the engine exhaust gases, EGR gases, engine cooling fluid, lubrication fluid, charged intake air, etc. is converted by the waste heat recovery system into mechanical energy by the expander and is transferred in mechanical form from the expander of said waste heat recovery system towards a compressor provided in the exhaust line. The recovered energy is used to compress the exhaust gases, or more particularly to benefit from the suction effect at the input of the compressor, in order to reduce the exhaust back pressure on the engine which is prejudicial to the engine efficiency. Such back pressure is all the more high as a fairly high number of devices are now commonly arranged in the exhaust line for various purposes, such as for reducing air pollution, for reducing noise and/or for recovering energy. Therefore, the energy needed for reducing the exhaust back pressure is recovered by means of the waste heat recovery system without needing an intermediate form of energy transfer other than the mechanical energy transfer from the expander to the compressor.