Abstract: A stratified charge internal combustion engine comprises at least one cylinder having at least one intake valve 14 per cylinder, and two manifolds 24, 34 having branches 22, 32 supplying first and second gas streams to at least one intake valve of each cylinder. The two streams enter the cylinder separately through different regions of the valve 14 so as to produce a stratified charge within the engine cylinder. The first manifold 24 supplies a stream comprising air within which fuel to be burnt is dispersed and the second manifold 34 supplies a stream comprising dilution gases. Each of the two manifolds 24, 34 has a plenum chamber and the plenum chambers of the two manifolds are connected to a common air supply throttle 50. The plenum chamber 34 of the second manifold is additionally connected to an exhaust gases recirculation (EGR) pipe 84 from the exhaust system of the engine through an EGR throttle 54 of similar design to and mechanically ganged with the air supply throttle 50.

Abstract: A multi-cylinder spark ignition internal combustion engine is described having two banks of cylinders 10a, 10b. One bank of cylinders may be selectively disabled by cutting off its fuel supply while continuing to receive air. The exhaust system includes an NO.sub.x trap 20 to store NO.sub.x gases while the exhaust gases contain excess air. During part load operation, the engine is run with one bank of cylinders disabled most of the time during which NO.sub.x gases are stored in the NO.sub.x trap 20. In order to permit the trap 20 to be regenerated or purged periodically, both bank are fired at is the same time for short intervals to supply a stoichiometric or reducing mixture to the exhaust system.

Abstract: A spark ignition internal combustion engine is provided including an intake manifold. A main throttle regulates the intake of ambient air into the intake manifold. An EGR pipe is connected between a point in the intake manifold downstream of the main throttle and a point in the exhaust system located downstream of the main restriction to exhaust gas flow. The exhaust gas pressure at the latter point is substantially constant during engine operation. An EGR throttle is rigidly connected for movement with the main throttle. The EGR throttle has a similar geometry to the main throttle such that the flow cross sections of the main throttle and the EGR throttle are in a fixed predetermined ratio to one another for all positions of the main throttle.

Abstract: An intake system for an internal combustion engine is described having an intake port 120 divided by a twisted partition wall 123 into two helical channels 121, 111; 122, 112. The end of the partition wall 123 adjacent the intake valve 113 lies in a plane generally perpendicular to the stem of the intake valve 113 and the part of the partition wall 123 at the other end of the intake port 120 lying in a plane generally parallel to the stem of the intake valve 113.

Abstract: An internal combustion engine is described having one or more combustion chambers 10 each having an intake port 16, a fuel injector assembly 30 for injecting fuel into the intake port 16 and means 20, 22, 24, 26 for supplying pressurised gas to assist in fuel atomisation of the fuel metered through the fuel injector assembly 30.The means for supplying pressurised gas comprises a passage 20, 24 incorporating a passive flow restrictor 22 having no moving elements. The passage 20, 24 leads from one of the combustion chambers 10 of the engine to the intake port 16 and is operative to deliver a single pulse of gas to the intake port 16 during each combustion cycle of the engine in order to assist in the atomisation of fuel which is injected into the intake port 16 at the same time as the pulse of gas.

Abstract: A variable compression ratio internal combustion engine has a piston connected to a crank pin on the crankshaft by means of a connecting rod formed in two parts, with the first part being rotatably secured to the crankshaft, and the second part being rotatably secured to a gudgeon pin of the piston. The two parts are connected to each other by a coupling including two eccentrics having axes of eccentricity that are inclined to one another so that the eccentrics cannot both lie in a dead center position at the same time.

Abstract: An intake system is described for a spark ignition internal combustion engine having ports per cylinder, which may lead to a common intake valve or two separate intake valves. One of the intake ports (12) is shaped to direct a first flow tangentially near the outer periphery of the cylinder and the other intake port (20) is shaped to direct a second, swirling, flow towards the center of the cylinder. The second swirling flow has the same direction of rotation as that of the first flow. Injectors (28) are provided for introducing fuel into the second swirling flow thereby producing within the cylinder a charge that is radially stratified with a combustible mixture concentrated near the center of the cylinder.

Abstract: The present invention relates to a compressed gas supply system in an internal combustion engine which may be used for example for an air-assisted or an air-driven fuel injector.

Abstract: A control system (14) is described for an internal combustion engine having a catalytic converter and a heater (12) for raising the temperature of the catalyst in the catalytic converter. The control system comprising an electrical circuit (16) for estimating, rather than measuring, the temperature of the catalyst and means for controlling the heater (12) of the catalytic converter based on the estimated catalyst temperature.

Abstract: A downdraft type carburetor having essentially conventional idle speed and main fuel metering systems has a throttle body or plug movable within a fixed area venturi to provide sonic flow at idle and part throttle operations; the plug is slidably mounted on a fuel tube extension of a centrally located main fuel discharge snout, and discharges fuel into a high velocity constricted area or throat formed between the plug and fixed area venturi.