Abstract: A fuel injection timing system for a compression ignition engine makes use of a read only memory programmed to provide a digital output representing the time or shaft angle when injection is required in accordance with the values of digital input corresponding to speed and engine load. The speed data is obtained from a transducer which also provides position signals enabling an injection datum to be established so that a comparator can compare the output of the memory with a digital signal representing shaft angle or time to trigger injection at the required instant.

Abstract: An angular position signal generator includes a rotor and a stator each having an arrangement of salient magnetic poles. The poles on the rotor are all of the same polarity and are spaced at unequal angles around the axis of the rotor. The poles on the stator are identically arranged so that in at least one position of the rotor all the poles are aligned and in at least two other positions only some of the poles are aligned. As the rotor rotates, therefore, the flux flowing between the poles fluctuates and a winding in the flux path produces pulses of different magnitudes at these various positions of the rotor.

Abstract: A fuel injection system for a V- or flat-type internal combustion engine with split intake/exhaust systems, includes injectors respectively associated with the intake systems and a pair of transducers associated with either the intake systems or the exhaust systems. A control unit alternately energizes the injectors in known manner and the outputs from the control unit to the injectors are used to operate a multiplex circuit whereby the transducers are alternately connected to the control unit, to control the pulse length of the output pulses therefrom.

Abstract: A vehicle tire pressure warning system includes a rotating assembly and a non-rotating assembly. The non-rotating assembly includes a magnet and a pick-up coil. The rotating assembly includes a series circuit comprising a coil, a magnetically operated switch and a pressure actuated switch which is closed when the tire pressure is adequate. The magnetic switch is closed periodically by the magnet and current is induced in the coil. When the magnetic switch re-opens the coil is coupled to the pick-up coil and the flux collapse in the coil causes a signal to be induced in the pick-up coil. The absence of such a signal indicates that the tire pressure is too low and is detected by a counter system for each wheel which counts the number of pulses from all the wheels between pulses from the associated wheel.

Abstract: A fuel injection system for a compression ignition engine includes pulse length control means which determines the instant and duration of opening of a series of injector valves in accordance with the output of a digital memory unit, empirically programmed to match the specific engine. The memory is addressed by two inputs, one derived from an engine speed transducer and the other derived by combining analogue signals from the speed transducer and from a demand transducer. The system operates without any feedback representing the quantity of fuel injected so that no fuel flow transducers are required.

Abstract: In an engine control system, particularly for fuel injection, the frequency of a variable frequency clock is compared with an output signal from a memory device and the difference used to control an engine function. The frequency of the clock is determined by the collector current of the transistor having two variable resistors controlling its emitter and base currents respectively. This invention relates to engine control systems and is particularly, but not exclusively, intended for use in fuel injection systems for engines.

Abstract: A pulse waveform recognition circuit includes an input stage consisting of a tuned circuit tuned to approximately the frequency of a sinusoid to half-waves of which the pulses to be recognized approximate. A transistor is biased to conduct weakly and has its base coupled to the tuned circuit so as to be turned on by a pulse within the band width of the tuned circuit. The transistor drives a monostable multi-vibrator with a frequency dependent feedback circuit which causes the reversion time of the multi-vibrator to decrease as the frequency of triggering increases and which also increases the threshold voltage required to trigger the monostable circuit as this frequency increases. The circuit is used in an ignition system for an i.c. engine.

Abstract: A lamp assembly has a housing of which part defines a parabolic or paraboloidal mirror and part defines part of an ellipsoidal reflector. A lamp filament is mounted at the inner focal point of the reflector and the focal point of the mirror coincides with the outer focal point of the reflector. The housing has a lens element defining a window through which light is directed from the mirror.In one embodiment, an additional mirror and lens element are provided for receiving light from the reflector. The additional mirror directing the light in the opposite direction to the light directed by the first mentioned mirror.In another embodiment, further mirrors are provided in the housing for increasing the horizontal spread of light.

Abstract: An electrical switch has an operating member movable between two positions and includes a light transmissive region in the operating member. The region is illuminated by a light source acting through a lens. Movement of the operating member between the two positions changes the relative position of the lens and the light source such that the area and intensity of the light on the light transmissive portion is varied in said two positions. This variation provides a visible indication of the operative position of the switch.

Abstract: A headlamp tilting mechanism in a motor vehicle comprises a pair of spring arms mounted in opposition on a shaft which is pivotable relative to the motor vehicle body and which carries a pair of headlamps. One end of each spring arm has attached thereto one end of a sleeved cable. One cable is attached to an unsprung part at the rear of the vehicle and the other cable is attached to an unsprung part at the front of the vehicle. Both cable sleeves abut against the underside of the vehicle body. Changes in the attitude of the vehicle body relative to the front and rear wheels cause changes in the tension of the cables to effect biasing of the spring arms so that a resultant rotation of shaft is effected which corresponds to the change in attitude of the vehicle body.

Abstract: A corona discharge gas flow transducer includes a high tension discharge electrode, and a receiving electrode having two terminals, the difference between the current flow from these terminals representing the gas mass flow. For deriving a current difference signal there is a circuit comprising a current to voltage converter, switch means alternately connecting the two terminals to the converter, and further switch means a.c. coupled to the converter and operable in synchronism with the switch means.The transducer is used in an i.c. engine fuel system in which the transducer output is integrated over a fixed engine crankshaft angle to generate a fuel demand signal.

Abstract: The motor vehicle comprises a vehicle body suspended on wheels and carrying a pair of headlamps which are mounted on a common cross rod angularly movable relative to the body by means of a headlamp tilting mechanism. The headlamp tilting mechanism is of the hydromechanical type and includes a lever which is mounted on the vehicle body through the intermediary of a pivot. The lever has an arm which is urged by spring into engagement with a temperature sensitive element secured to a rear axle housing of the motor vehicle. An extension projecting from the lever is engaged by an output rod of a mechanism for rendering the tilting mechanism inoperative. The mechanism comprises a body within which is disposed a bellows element having the output rod secured thereto. Also disposed within the body is a temperature expansible material and a heating element which is arranged to be heated when a headlamp filament energizing switch is manually closed.

Abstract: A lamp assembly comprises a reflector body having an aperture in the rear thereof which is closed by a bulbholder. The bulbholder houses electrical contacts for engaging a bulb which contacts are integrally formed with respective electrical terminals which project from the bulbholder. The bulbholder is welded to the reflector body so as to trap respective electrical connectors, which form part of a printed circuit power supply, between the electrical terminals and the reflector body, so that the electrical terminals are electrically connected to the respective electrical connections, a power supply thereby being provided to the bulb.

Abstract: An i.c. engine fuel injection control includes a corona-discharge type transducer for measuring the mass of air aspirated by the engine. Since such a transducer is humidity sensitive a compensation circuit is provided for automatically applying a humidity correction to the control circuit which is used to control the quantity of fuel injected as a function of the transducer output. This control circuit includes an integrator to which the transducer output is periodically applied and a current source which periodically discharges the integrator, the time taken to discharge determining the quantity of fuel injected. The current source is controlled by the humidity sensitive means, to obtain the required compensation.

Abstract: An engine exhaust recirculating valve is operated by a solenoid. The valve is normally open, but has an electronic control circuit, including an engine speed transducer, which energizes the solenoid to close the valve when the engine speed is above a predetermined level.

Abstract: A lamp assembly comprises a hollow body having two recesses therein, a bulbholder and a reflector in each recess, and a colorless transparent lens extending across the openings of the recesses. In one of the recesses is mounted a standard bulb and a filter element in the form of a domed cover surrounding the bulb. A neutrally colored light-absorbing material is incorporated into the filter element or is provided as a layer over a surface thereof remote from the bulb.

Abstract: A direction indicator switch having a body, a rotor, and detent means on the body and the rotor for releasably retaining the rotor in any one of a rest, and first and second operative positions. A detent release member is movable with the rotor and is also movable relative to the rotor to release the detent means, and carried by the body is a pawl. The pawl is resiliently urged towards a projecting position wherein the pawl intersects the orbit of a striker rotating with the vehicle steering shaft. The pawl is capable of movement relative to the body about first and second spaced parallel axes, and is permitted to move to its projecting position when the rotor of the switch is moved to either of its first or second operative positions. During cancelling movement the pawl is moved by the striker, and in turn co-operates with the detent release member to release the detent mechanism and thus to permit the rotor to be moved back to its central rest position by an inherent spring bias.

Abstract: A method for plating using a plating jig comprising a metal frame with an impervious covering of an electrically insulating material on the frame. At least one part of the frame is bare of the covering to permit contact being made with a component to be held by the jig for plating. A contact piece encloses said bare part and is formed of a non-conductive resiliently compressible matrix containing conductive particles such that a conductive path is established through the matrix wherever this is compressed. The contact piece is arranged to be compressed by contact with a component on the jig so as to establish an electrical connection between the frame and the component.

Abstract: A process control apparatus, for example for internal combustion engine fuel injection control, includes a digital memory which produces an n-bit digital output in accordance with two independently variable input signals. The m most significant bits are transferred to a counter which is clocked to give a pulse length output. The n-m least significant bits control a logic circuit which is used to program another counter which is used to introduce an added delay to each output pulse. This arrangement enables higher resolution to be obtained using a limited size main counter.

Abstract: A road vehicle electrical system has an alternator which provides power through a rectifier to a battery, and also supplies a third supply line used for feeding an ignition warning lamp. Control means for the starting system of the vehicle is associated with the supply lines in such a way that once the engine has started and the third supply line is energized, a further attempt cannot be made to start the engine until the engine has stopped.