Internal combustion engine having an exhaust gas turbine

Claim 1

In combination with an internal combustion engine having at least one cylinder carrying a respective reciprocally movable piston, a respective cylinder head closure on said at least one cylinder and closing the end of the respective said cylinder to define a respective combustion chamber with respect to said cylinder piston, inlet manifold means connected with said cylinder for conveying at least an oxygen-containing gas thereto, means for admixing incoming fuel with the oxygen-containing gas, ignition means for firing the fuel in the oxygen-containing gas, to develop power, and exhaust port for the periodic discharging of hot, high pressure combustion products from said cylinder, said exhaust port being disposed in a respective boundary wall of the combustion chamber or cylinder; the improvement comprising: (a) at least one respective nozzle means adapted for accelerating and conveying the hot, high pressure combustion products from the respective said cylinder to a turbine, said nozzle means having inlet and discharge ends and having its said inlet end contiguous said boundary wall at said exhaust port and sealingly encompassing said exhaust port so as to prevent leakage of said hot, high pressure combustion products to the atmosphere; (b) a valve means; (c) means coupled to said valve means for controlling said valve means to allow cylinder combustion gases to flow through the nozzle means near the end of the expansion (power) stroke of the piston; and (d) at least one turbine having respective inlet and discharge passageways and an output shaft for delivering power and disposed closely adjacent the nozzle means and having its inlet passageway connected with said discharge end of said nozzle means and sealingly connected therewith so as to prevent leakage of said expanded, high velocity combustion products to the atmosphere and constraining said expanded, high velocity combustion products to pass through said turbine, thereby giving up their energy to said turbine to become low pressure, low velocity exhaust gas, said discharge passageway conveying said low pressure exhaust gas away from said turbine; said nozzle and valve means including a combination variable geometry nozzle throat valve that varies the nozzle during blowdown beginning with a convergent-divergent nozzle structure at high cylinder pressures so as to produce supersonic flow at initial high cylinder pressures and progresses with smaller discharge end-to-throat area ratios to a simple converging nozzle structure for sonic and slower flows at the succeedingly lower cylinder pressures, that provides variable nozzle shapes throughout the valve opening sequence and that eliminates otherwise irreversible valve throttling losses ahead of said nozzle means, thereby maximizing the nozzle exit gas velocity and energy recovery by the turbine whereby said output shaft of said turbine can deliver power efficiently removed by said variable geometry nozzle valve and said turbine from said hot, high pressure cylinder combustion gases.