Air pollution-free internal combustion engine and method for operating same

Claim 1

A dual mode method for operating an internal combustion engine having at least one cylinder, a piston reciprocating in said cylinder, an exhaust port in said cylinder and an exhaust valve in said port, means for injecting fuel, water and an oxidant selected from the group consisting of substantially pure oxygen gas and an oxygen containing gas into said cylinder, means for supplying said fuel, oxidant and water in metered amounts to said injecting means, means for interrupting the supply of either substantially pure oxygen gas or oxygen containing gas in a manner whereby interruption in the supply of one type of oxidant discontinues interruption of the supply of the second type of oxidant so as to supply one or the other type oxidant to said oxidant injector, means for adjusting the metered amounts of fuel during transition between the two modes of operation in order to provide an amount of fuel capable of being completely combusted by the oxidant gas supplied to the oxidant injector, means for igniting the injected mixture of fuel and oxidant to produce combustion, and means for cyclically opening and closing said exhaust valve, which comprises at least one cycle comprising: a. interrupting the supply of oxygen containing gas to said oxidant injector means and initiating a supply of substantially pure oxygen gas to said oxidant injector means; b. adjusting the metered amount of fuel to an amount capable of being completely combusted by the substantially pure oxygen supplied to said oxidant injector means, and then c. carrying out at least one cycle comprising the steps of: i. closing said exhaust valve prior to completion of the exhaust stroke to entrain a limited amount of exhaust gas in the cylinder as a working fluid; ii. injecting a metered amount of substantially pure oxygen gas into the cylinder after the exhaust valve closes and prior to the piston reaching top dead center on its exhaust stroke, said oxygen injection occurring while relatively low pressures exist in the cylinder, and said amount of oxygen injected being at least a stoichiometric quantity; iii. injecting a metered amount of fuel into the cylinder under high pressure, after injection of the oxygen, so that the fuel burns progressively as it is injected; iv. combusting the mixture of oxygen and fuel injected into the cylinder; v. opening said exhaust valve after said fuel and oxygen are combusted and discharging the exhaust gas from said cylinder; and vi. injecting a metered amount of a water spray into said cylinder, while said exhaust valve is open, to cool the cylinder wall, piston, dome, combustion chamber wall and exhaust gas by vaporization of the water; d. then interrupting the supply of substantially pure oxygen gas and initiating the supply of an oxygen containing gas to said oxidant injector; e. adjusting the metered amount of an amount capable of being completely combusted by the oxygen containing gas supplied to said oxidant injector means, and then f. carrying out at least one cycle comprising steps (i) (ii) (iii) (iv) (v) (vi) above except that substantially pure oxygen gas is replaced by the oxygen containing gas.