Abstract: A management system of an engine having a hot operating system (a catalytic converter or fuel vaporiser) and a rapid heating system for the hot operating system includes a clock and means to operate the clock after the engine has stopped where the clock operates to issue a signal indicating the time since the last engine switch off. An estimator is coupled to the clock for estimating the temperature of the hot operating system prior to restarting the engine on the basis of signals from the clock indicating the time since last engine switch off and a heating system controller controls the rapid heating system in dependence upon the estimated temperature of the hot operating system prior to restarting the engine.

Abstract: A method is described for operating an engine having an afterburner and a catalytic converter downstream of the afterburner. Sufficient excess fuel is introduced into the engine to produce in the exhaust gases fuel constituents including unburnt hydrocarbons, carbon monoxide and hydrogen. Unburnt hydrocarbons are intercepted upstream of the afterburner so as to allow substantially only carbon monoxide and hydrogen to reach the afterburner. Sufficient additional air is introduced into the exhaust system to bring the composition of only the carbon monoxide, hydrogen and air to stoichiometry or leaner than stoichiometry, the resulting concentration of hydrogen and oxygen in the mixture reaching the afterburner being sufficient for ignition immediately after a cold start.By removing the hydrocarbons temporarily before the exhaust gases reach the afterburner, reliable cold ignition can be achieved with lower levels of fuel enrichment.

Abstract: An intake manifold system 10 is described for a multi-cylinder four stroke spark-ignition internal combustion engine 12. Each cylinder has at least one intake port 20, each intake port 20 being connected at one end to the combustion chamber by at least one intake valve 14 and at the other end to a first intake duct 22 that is connected to a first plenum 24 common to the first intake ducts 22 of other engine cylinders. Each intake port 20 is also supplied by a second intake duct 32 the through flow cross-section of which is at least 15% of the maximum effective through flow cross-section of the open intake valve and controlled by a variable throttle 40, the second.

Abstract: A method is described of operating an internal combustion engine burning a fuel containing carbon and hydrogen, to provide a flame in the exhaust system to heat a catalytic converter or burn off the soot in a particulate filter trap. The method involves reducing the intake throttle opening during deceleration mode below the throttle opening for the steady speed idle position to create a proportion of combustible gases in the exhaust gas stream. By ensuring at the same time the presence in the exhaust gas stream of additional air, an ignitable mixture is produced which is ignited to burn as a flame in an afterburner chamber of the exhaust system. By selecting deceleration periods to enrich the mixture excessively in this manner, adverse effects on drivability go unnoticed.

Abstract: An internal combustion engine 12 in which liquid fuel is introduced prior to the charge entering the combustion chambers is mounted in a vehicle having an air scoop 34 which acts as a source of ram air pressurised by the movement of the vehicle. The ram air is fed into the exhaust system by way of an isolation valve 36 which is opened only during engine deceleration modes and serves to reduce emissions of unburnt hydrocarbons and carbon monoxide caused by the fuel wetting the intake manifold.

Abstract: A phase change mechanism is described for varying the phase of an engine camshaft relative the engine crankshaft.

Abstract: A catalytic converter comprises two catalytic matrices 10, 12, 14 mounted in a common housing and spaced from one another by an afterburner chamber 16. An igniter 22 is arranged in the afterburner chamber 16 near the first matrix 12 and a flame guard 18 is arranged upstream of and in close proximity to the igniter 22. The flame guard 18 comprises at least one elongate narrow strip spanning the combustion chamber which acts to spread the base of the flame across the width of the chamber 16 so as to enable the flame to spread in a shorter distance across the exhaust gases before reaching the second matrix 14.

Abstract: A method is described for reducing the total emissions during cold starts from an engine burning a hydrocarbon fuel and having an afterburner arranged upstream of a catalytic converter. The method comprises the steps of:(i) adding an excess of fuel to the engine combustible charge and adding air to the engine exhaust gases immediately after the engine has first fired to assure the presence in the exhaust/air mixture of sufficient concentrations of hydrogen and oxygen to permit the resulting exhaust/air mixture to be ignitable and to burn with a steady flame in the afterburner while the latter is at a temperature close to the ambient temperature, and(ii) igniting the exhaust/air mixture in the afterburner immediately after the engine has first fired.

Abstract: An intake system for an internal combustion engine has a plurality of intake tracts connected in use to extend from individual engine intake ports to a common plenum chamber and a common passage opening into the plenum chamber for supplying air to all the intake ports. The tracts are arranged to open into the plenum chamber in pairs associated with pairs of intake ports, each pair of intake ports having valve events which do not overlap. The ends of each pair of tracts disposed within the plenum chamber are arranged directly facing one another and are separated by a gap which is sufficiently wide to permit mass air flow between the respective tracts and the common passage but which is sufficiently narrow to couple most of any pressure wave energy emanating from one tract directly into the facing tract.

Abstract: A four-stroke spark ignited internal combustion engine has a variable volume working chamber and an auxiliary chamber having a fixed volume which is smaller than the maximum volume of the working chamber, with the working chamber and the fixed chamber being communicated by a series of passages in the cylinder wall. The passages in the cylinder wall are situated such that when the piston is near the top of its exhaust stroke, the end gases stored in the auxiliary chamber are discharged into the crankcase.

Abstract: An internal combustion engine has a crankshaft, a camshaft driven by the crankshaft through a drivewheel at half the crankshaft speed and at least one cam on the camshaft for actuating a spring-biased poppet valve. To achieve variable event timing, a lost motion coupling is arranged between the drive wheel and the camshaft. During the opening of the valve, the camshaft rotates at substantially the same speed as the drive wheel, but during the closing of a valve, the camshaft is accelerated by the valve spring to lead the drive wheel and thereby reduce the duration of the valve event. It is alternatively possible to collapse the opening phase of the valve event rather than the closing phase by reversing the operation of the coupling.

Abstract: A method of reducing the light-off time of a catalytic converter comprising exposing the matrix of the converter to an alternating magnetic field or to electromagnetic radiation having a frequency such that the washcoat and the catalyst particles supported by the matrix are heated to the light-off temperature without a corresponding increase in the temperature of the entire matrix. The catalytic converter includes a matrix formed in two or more parts, of which the downstream parts are conventional. The upstream part of the matrix consists of a honeycomb made of a material which does not absorb microwave energy, is coated with a washcoat dispersed with catalyst particles which does heat up when exposed to microwave energy, and is enclosed in a waveguide having perforated walls through which exhaust gases can flow.

Abstract: A phase change mechanism for a camshaft of an internal combustion engine comprises a drive member to be connected to the camshaft drive train, a driven member to be connected to the camshaft, a coupling element interposed between, and movable relative to, the drive and driven members, and means connecting the coupling element for rotation with the drive and driven members in such a manner that the phase of the driven member relative to the drive member is dependent upon the position of the coupling element.

Abstract: A spark plug is disclosed having a metal body 18, a center electrode 16 and an insulator 14 surrounding the center electrode, the part of the insulator disposed within the combustion chamber being separated by an annular gap from the metal body of the spark plug. In order to reduce cycle to cycle variations, a filler 12 of very poor thermal conductivity is used to fill the gap between the insulator 14 and the body 18 to prevent gas movement in this gap, thereby preventing the gap from forming part of the combustion chamber.

Abstract: An internal combustion engine is described in which each combustion chamber (10) in the engine has an associated auxiliary chamber (18), and in which, for low compression ratio operation, the auxiliary chamber (18) is constantly connected to the combustion chamber (10) and, for high compression ratio operation, the auxiliary chamber (18) is connected to the combustion chamber (10) by a one way valve (24, 36, 38, 40) which permits gas flow only in the direction from the combustion chamber (10) towards the auxiliary chamber (18).

Abstract: The invention relates to a manifold system for an internal combustion engine comprising a shutter (22) serving as an externally controlled source of pressure waves disposed within a tract (10) and activated at a predetermined time preceding the closing of an associated engine valve (12) such that the pressure pulse from the shutter reaches the associated valve (12) as it is closing during each engine cycle.

Abstract: The invention relates to a spark ignited engine in which charge stratification occurs within the combustion chamber and in which the burn quality of the charge is dependent upon the timing of the instant of introduction of the fuel into the charge. A sensor is provided to produce a signal representative of the burn quality and the fueling timing is controlled in dependence upon the output signal of the sensor so as to optimize the charge stratification within the combustion chamber.

Abstract: A cylinder head gasket is described which also serves as an electrode of an ionization sensor. The gasket (16) has an electrically conductive surface portion (16c) which is electrically insulated from the cylinder head (14) and from the engine block (12) so that it may serve as an electrode of an ionization sensor. The gasket of the preferred embodiment is of five layer sandwich construction comprising two outer layers (16a, 16b) of soft metal capable of deformation under pressure to effect a gas tight seal with the block (12) and the cylinder head (14), a central core (16c) of electrically conductive material to serve as an ionization electrode and two layaers of ceramic material (16e, 16f) insulating the central core (16c) from the two outer layers (16a, 16b).

Abstract: A variable camshaft phasing mechanism is described comprising concentric drive and driven members (12, 10) rotatable respectively with a drive pulley (12) and a camshaft (14). The members (10, 12) are coupled to one another by means of an eccentric cranking element (18) on one of the members (12) engaged by two hydraulic jacks (28, 30) on the other member (10). Valves (36) are provided for controlling the flow of the hydraulic fluid from the chamber of the hydraulic jack (28, 20) to lock the members (10, 12) against rotation relative to one another in different relative angular positions of the members and to permit flow from either of the cylinders of the jacks to the other.

Abstract: An engine crankshaft has a crankpin that is radially slidably mounted relative to the crankshaft axis so that its axis can follow other than a circular path centered on the cranking axis. The mechanism includes at least one main bearing section with a stationary eccentric bearing surface, and at least one web fixed to the crankshaft and extending radially from the main bearing section. A housing is slidably mounted on guide surfaces on the webs for a sliding movement along the web, and has a crankpin secured thereto. The non-rotating eccentric bearing surfaces engaged by the housing force the housing to slide radially in and out along the web in synchronism with rotation of the crankshaft such that the distance of the center of the crankpin axis from the center of the main bearing section axis varies as a function of the angle of rotation of the crankshaft.