Abstract: Disclosed is a fuel/gas delivery system for use with operating an internal combustion engine in which quantities of a hydrocarbon fuel and hydrogen are introduced into the combustion chamber of the engine. The combustion chamber is provided with an igniter and the delivery of hydrogen is timed relative to both the delivery of the fuel and the activation of the igniter to establish an ignitable mixture at the igniter at the time of activation of the igniter.

Abstract: A multi-cylinder two-stroke cycle engine according to the invention incorporates a plurality of cylinders (1,2,3) arranged in line with each cylinder having at least two inlet ports one on each of the two opposite longitudinal sides of the in-line cylinders (1,2,3). Air passages (67,77) extend along said opposite sides to supply air from a supercharger (not shown) to the respective inlet ports. An air control valve (68) is operable to selectively control air supply to one or both of said air passages (67,77) whereby optimum combustion conditions are obtained for various engine load/speed conditions. A centrifugal supercharger arrangement is also disclosed, the supercharger being coupled to the engine crankshaft and interposed between the cylinder block and the engine flywheel.

Abstract: A multicylinder two-stroke cycle internal combustion engine (10) comprises an individual crankcase cavity (18) for each cylinder to receive the incoming air charge for that cylinder and a cylinder block (11) with at least two cylinders having cooperating crankcase cavities (18) provided with valve controlled intake ports (19) in a common wall (31) of the cylinder block (11). An air induction manifold (25) is detachably mounted to the common wall (31) to form a single air induction cavity (27), at least part of which is formed within the cylinder block (11), and has a single main inlet port for regulation of air inflow to the induction cavity (27). Individual passages (33) communicating each crankcase cavity inlet port (19) with the air induction cavity (27) are formed in the manifold (25). Acceptable performance with limited increase in the overall physical dimensions of the engine (10) can thus be obtained.

Abstract: A method of operating a two-stroke spark ignition engine (9) wherein the fuel is injected directly into the engine combustion chamber (22). The timing of the injection of the fuel and the ignition of the fuel charge are varied according to engine load and speed conditions. Under low load and speed conditions substantially all the fuel is injected after closure of the exhaust port (20) and the fuel charge is ignited between 40 and 70 degrees of crank angle rotation before the top dead center point of the engine cycle. Under high load conditions substantially all the fuel is injected before exhaust port closure.

Abstract: A two stroke cycle engine 10 with an exhaust gas treatment catalyst. Separate reducing and oxidizing catalyst portions 126 and 127 are provided to treat different portions of the exhaust gas exhausted during each exhaust period. The portion of the exhaust gas high in NOx, usually that first exhausted upon initial opening of the exhaust port, is directed to be treated by the reducing catalyst 126 and the remainder of the exhaust gas is directed to be treated by the oxidizing catalyst 127.

Abstract: A two-stroke spark ignited engine (10) with direct fuel injection (14) and an exhaust gas treatment catalyst. A separate catalyst unit (23) is provided for each combustion chamber (11) and is located at or adjacent each exhaust port (15) from that chamber and that during a cycle of each combustion chamber (11) the catalyst unit (23) of that combustion chamber (11) is exposed only to exhaust gases which change from chemically reducing to chemically oxidizing during the cycle. An engine which has exhaust gases which are overall chemically oxidizing can thus nevertheless have the NOx constituents of the gases reduced.

Abstract: Method and apparatus for controlling emissions, particularly of unburnt hydrocarbons, from a two stroke engine. The engine has direct in-cylinder fuel injection and has in the air inlet port and the exhaust port respective devices to control the flow therethrough. The devices are each independently controlled in relation to engine load demand and engine speed to regulate the mass of exhaust gases retained in the combustion chamber. The exhaust flow control device perferably also alters the timing of opening and closing of the exhaust port.

Abstract: A multi-cylinder engine block for an engine operating on the two-stroke cycle and having two or more adjacent cylinder bores (10,11,12) with the axes of the bores parallel and in a common longitudinal plane. Each cylinder bore having an exhaust port (20), and an exhaust passage (21) extending from each exhaust port (20) to an external surface (22) of the block in a direction generally at right angles to said common longitudinal plane (25). Two transfer ports (27,28) being provided communicating with the same cylinder bore on either side of the exhaust port in the direction of said common longitudinal plane. Each transfer port communicating with a respective transfer passage. The transfer ports (27,28) not extending beyond the common longitudinal plane (25), and the transfer passages (26,23) adjacent the respective transfer ports (27,28) extending in a direction generally tangential to the cylinder bore.

Abstract: Improvements in fuel injection nozzles for spark ignited internal combustion engines enabling a metered quantity of fuel entrained in a gas to be delivered into a combustion chamber to optimize the efficiency of operation of the engine. The fuel injection nozzle has a port (11) and a valve (15) movable relative to the port (11). Port (11) and the valve (15) have respective annular sealing faces (13) and (18) defining an annular frustoconical shaped throat (25) when the nozzle is open for the flow of metered fuel therethrough. The nozzle has a shroud (20) extending from the port (11) surrounding the periphery of the valve (15) when the nozzle is open and defining a delivery passage 27 downstream of the throat in the direction of fuel flow towards the combustion chamber. The delivery passage 27 is configured to be purged of fuel after each fuel delivery cycle to prevent carbon build-up in the nozzle.

Abstract: A method of operating a two-stroke spark ignition engine (9) wherein the fuel is injected directly into the combustion chamber (22). The timing of the injection of the fuel is varied according to engine load and speed conditions. Under low load and speed conditions at least 80% of the fuel is injected after closure of the exhaust port (20) whereas under some high load conditions at least 80% of the fuel is injected before closure of the exhaust port (20). The method may also comprise adjustment of ignition timing so that, in conjunction with low load and speed conditions, ignition occurs at least 5.degree. of crankshaft rotation after commencement of fuel injection and up to 70.degree. before top dead center of the engine cycle.

Abstract: A method of fuel injection for an internal combustion engine having one or more combustion chambers and wherein a metered individual quantity of fuel entrained in a gas charge is injected individually by the pressure of the gas directly into each combustion chamber each combustion cycle thereof. The method including the steps of delivering gas from at least one combustion chamber of the engine to a common gas reservoir, and controlling said delivery of gas to the gas reservoir to substantially maintain the gas therein at a pressure above the maximum compression pressure in the combustion chamber prior to commencement of combustion in said combustion chamber. Supplying gas at a regulated pressure from said gas reservoir to receive the metered quantity of fuel and effect in sequence delivery of that fuel into the respective combustion chambers of the engine.

Abstract: A method and apparatus for injecting fuel into a combustion chamber of an internal combustion engine particularly of two stroke cycle spark ignited engine, wherein a metered quantity of fuel is entrained in a gas, and the fuel and gas mixture so formed is delivered through a nozzle into the combustion chamber under conditions that will establish a fuel spray having a dispersion velocity in the direction of the spray axis of not more than 25 meters/sec at 35 millimeters of spray penetration from the nozzle when measured in still air atmospheric pressure, and preferably that dispersion velocity is not more than 18 meters/sec at 70 millimeters from the nozzle.

Abstract: A direct injected two stroke cycle internal combustion engine having a cylinder, a cylinder head at one end of the cylinder, a piston mounted for reciprocation in the cylinder, and an inlet port and an exhaust port in the wall of the cylinder at substantially diametrically opposite locations in the cylinder. A cavity in the cylinder head extending in a generally diametral direction from adjacent the cylinder wall at a location opposite the exhaust port. The cavity having substantially straight side edges in the direction of extension, and the longitudinal length of the cavity in said direction being about 0.55 to 0.77 of the diameter of the cylinder.

Abstract: A two stroke cycle engine 10 with an exhaust gas treatment catalyst. Separate reducing and oxidizing catalyst portions 126 and 127 are provided to treat different portions of the exhaust gas exhausted during each exhaust period. The portion of the exhaust gas high in NOx, usually that first exhausted upon initial opening of the exhaust port, is directed to be treated by the reducing catalysts 126 and the remainder of the exhaust gas is directed to be treated by the oxidizing catalyst 127.