GB1513958A - Internal combustion engine with exhaust gas recycling system and method for operating such engine - Google Patents

Abstract

1513958 Closed-cycle engines SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV 9 June 1975 [11 June 1974] 24650/75 Heading F1B A method of operating a closed-cycle I.C. engine with exhaust gas re-cycling comprises the steps of supplying hydrocarbon fuel and pure oxygen to the engine, recycling exhaust gas from the exhaust manifold to the inlet manifold, treating at least part of the exhaust gas during the recycling step to liquefy CO 2 and removing liquefied CO 2 from the recycled gas. An apparatus for carrying out the method includes an I.C. engine 2 leaving an exhaust manifold 3 leading to cooler 6 and valve 15 which directs some of the exhaust gas through a conduit 13 and the remainder through a compressor 7, a cooler 8 in which carbon dioxide liquefies and a separator 9 which directs liquid into a pipe 17 leading to a pump 19 and storage chamber 20. The rest of the exhaust gas, substantially free of carbon dioxide, passes through pipe 16 and is mixed with oxygen evaporated from a storage tank 21. The mixed gases pass through control valve 10 and are further mixed with exhaust gas from conduit 13 before entering inlet manifold 4 via a heater 11. Hydrocarbon fuel from tank 23 is supplied to engine 2 through flow measuring device 25 which provides a signal, representative of the rate of fuel-flow, to controller 26, which also receives from sensor 28 a signal representative of the oxygen content of the mixed gases. Controller 26 adjusts valve 10 to maintain a flow of oxygen appropriate to the fuel-flow. In a second apparatus, the re-cycling circuit is combined with an absorption refrigeration system in which the gases leaving the exhaust manifold pass through a heat exchanger in the refrigeration system boiler, through a wet scrubber to a valve corresponding to the valve 15, to a drier, a cooler, a compressor and pre-cooler, and then to a final cooler which is the evaporator of the refrigerator system. The mixture of exhaust gas and oxygen fed to the engine is passed through a heater which utilizes the heat in the exhaust gas leaving the engine, or the liquid coolant used in the engine, or an electrical heater. The apparatus is suitable for use in a submerged vessel or diving bell. The engine has a compression ratio of over 18 e.g. between 28 and 55 and when operating at a C.R. of 55 on a mixture of carbon dioxide and oxygen the temperature at T.D.C. the same as that reached when operating on air with a C.R. of 17À5. The optimum compression ratio is stated to be 30.