Abstract: A fluid operated braking system for a motor vehicle, having a main braking circuit for applying braking pressure to the actuators of both wheels of at least one axle of the vehicle and a subsidiary braking circuit for applying a reduced braking pressure to one of the wheels of the axle if it should enter a skid or incipient skid state, in which the subsidiary braking circuit is controlled by two distributors each of which has three ports, one connected to the main braking circuit, one connected to the subsidiary braking circuit, and one connected to the brake actuator of an associated wheel of the axle, the distributor being controlled by an electrovalve to connect the main braking pressure circuit to the brake actuator of the associated wheel of the axle under normal condition and to connect the subsidiary braking circuit, through an internal path within the distributor to the brake actuator of one wheel of the axle when this wheel enters a skid or incipient skid state, without affecting the distributor asso

Abstract: A combustion chamber for a diesel engine has a secondary chamber, communicating with a precombustion chamber, the secondary chamber consisting of a central channel extending diametrically in the piston crown and having at its discharge end two branches, forming an anchor configuration, which induce turbulence in the combustion gases, grooves being provided in the piston crown to trap gases escaping from the central channel.

Abstract: Apparatus and method for recovering fuel from the induction system of an internal combustion engine having a carburetor, comprising one or a plurality of collectors along the fuel path between the carburetor throttle valve and the inlet valves of the engine, the collectors being in the form of annular recesses in the walls of the ducts, which recesses act to trap fuel which flows back as a liquid condensed onto the inlet manifold pipes as a reaction to the closure of the associated inlet valve of the engine. Each collector is connected by a drainage systems of conduits via expansion tanks and a pump, to the petrol tank of the engine and/or to the inlet to the carburetor whereby fuel which condenses prior to being drawn into the engine can be recycled for vaporization thereby avoiding its entry into the engine as a liquid.

Abstract: A fluid operated braking system for a motor vehicle, having a main braking circuit for applying braking pressure to the actuators of both wheels of at least one axle of the vehicle, and a subsidiary braking circuit for applying a reduced braking pressure to one of the wheels of the axle if it should enter a skid or incipient skid state, in which the subsidiary braking circuit is controlled by two distributors each of which is associated with a respective wheel and has three ports, one connected to the main braking circuit, one connected to the subsidiary braking circuit, and one connected to the brake actuator of the associated wheel of the axle, the distributor being controlled by an electrovalve to connect the main braking pressure circuit to the brake actuator of the associated wheel of the axle under normal braking conditions, and to connect the subsidiary braking circuit, through an internal path within the distributor, to the brake actuator of the associated wheel of the axle if this wheel enters a skid

Abstract: A cylinder head for a compression-ignition (diesel) engine has a sector accommodating the upper part of a fuel injector between four valves, the sector being isolated from the tappet lubricating oil by a protecting casing on the upper part of the cylinder head. The casing may itself be sealed by a protective and sound-proofing cover.

Abstract: Automatic control of spark advance in an electronic ignition system for an internal combustion engine is effected by using a first electromagnetic pick-up cooperating with a protuberance which is phase-displaced on a rotary part (flywheel) relative to top dead center by the maximum advance angle required, and a second pick-up which cooperates with peripheral teeth on the rotary part. Pulses from the second pick-up are counted during a predetermined interval (T) initiated by a pulse from the first pick-up to provide a count which is stored as a reference value representing the required spark advance angle, this stored reference value being subsequently compared with the number of pulses from the second pick-up counted with the commencement of the next pulse from the first pick-up to provide a spark-triggering pulse upon parity of the number of these subsequently counted pulses with the reference value.

Abstract: A hydro-dynamic brake system of the type having a volumetric pump circulating brake fluid to a reservoir, and a modulating valve in the output of the pump acting under the control of the brake pedal to constrict the pipeline thereby increasing the pressure at the output of the pump. This pressure is fed to a distributor controlled by a solenoid valve and also receiving an input directly from a master cylinder which is also controlled by the brake pedal. Each wheel has a speed sensor feeding a processing and control circuit which produces an output signal to a solenoid valve which controls various transfer ports of the distributor. The distributor has a series of cylindrical cavities housing pistons which control valves in passages linking the chambers into which each cavity is separated by its piston.

Abstract: An electrical distribution system suitable for use on motor vehicles where electric current is to be supplied selectively to one or more electric power consuming devices, wherein there is provided a main power carrying conductor and a plurality of signal carrying lines which energize one or more of a plurality of actuators to interconnect the power line to a selected electrical device, in which the power line is in the form of a metal strip of sufficient rigidity that the actuators can be mounted thereon by a mounting which also makes electrical contact thereto.

Abstract: A device for automatically varying the ignition spark advance angle in an electronically controlled ignition system for an internal combustion engine, in which there is a first sensor for producing a train of pulses the pulse repetition frequency of which represents the engine speed and a second sensor for producing a single pulse once each revolution of the engine when the crankshaft is at the top dead center position.

Abstract: An improvement in pneumatic anti-skid braking systems for at least one wheel of a vehicle, of the type having a first valve system for causing a controlled reduction in braking pressure in a brake actuator upon reception of a control signal from an anti-skid control device sensitive to the dynamic state of at least one wheel of the vehicle, and a second valve system for causing a subsequent controlled rise in pressure after the signal from the anti-skid control device has been removed, the improvement being the provision of an accumulator in parallel with the first valve system and having two unidirectional valves, one at each side, which permit the accumulator to charge up to the braking pressure during normal braking, store this pressure upon anti-skid release of the braking pressure, and then deliver its charge to the circuit, causing a rapid increase of braking pressure after the anti-skid control signal is removed from the first valve system.

Abstract: A diesel engine fuel injection pump with electronic output regulation has an actuator cylinder for controlled displacement of a control rod which regulates a pumping element control screw. This actuator cylinder is machined in the pump body together with a seating for a distributor valve which controls the supply of hydraulic working fluid to the actuator cylinder. The working fluid may be the fuel itself.

Abstract: In a device for measuring ultrasonically the flow of gas, for example the air flow in the induction duct of an internal combustion engine, an upstream piezo-electric transducer is located in a plenum chamber upstream of a measurement duct and a downstream piezoelectric transducer is located in a seating in the measurement duct. To reduce vorticity in the gas flow the upstream transducer is seated at the apex of a frusto-conical element in the inlet chamber and the seating of the downstream transducer is tapered externally.

Abstract: A method and apparatus for the antiskid braking of a vehicle, of the type in which the signals representing the speed of two wheels of an axle of the vehicle are generated and used, together with a signal representing the deceleration of the vehicle to generate control signals for successive release and reapplication of the brakes during a braking operation, in which a signal representing the slowest wheel of the axle is compared with a reference signal generated cyclically from the said speed and deceleration signals in successive intervals of time using the expression ##EQU1## where A, B and C are predetermined constants, d.sub.v is the deceleration signal and T.sub.1 is the reciprocal of the signal representing the speed of the slowest wheel of the axle.

Abstract: A control circuit for cyclically operating one or more piezoelectric transducers to transmit and receive ultrasonic signals is disclosed. The circuit comprises a power transistor in series with an induction coil and controlled by a timing circuit to conduct for a short time during each cycle. As the power transistor cuts off a high voltage pulse is generated by the induction coil and this is fed via a zener diode as the transmission signal to the or each piezoelectric transducer across which is connected a switching circuit comprising a potential divider and a pair of opposite polarity diodes which automatically feed off the high voltage transmission signal to earth and pass low strength received signals to an amplifier.

Abstract: A control valve for controlling refrigerant circulation in a vehicle air conditioning system has an inlet port and an outlet port for connection to the evaporator and the compressor inlet respectively of the system, and a valve controlling communication between these two ports. First control means in the valve body control the valve in dependence upon one or more external controls including manual controls and second control means control the operation of the valve in dependence upon the thermodynamic conditions, such as the temperature, of the refrigerant fluid.

Abstract: An internal combustion engine having at least one cylinder, a combustion chamber externally of the cylinder and communicating with the cylinder, and spark ignition means, which preferably comprises a first electrode supported in a central region of the combustion chamber and a spark plug having a single electrode extending into the combustion chamber and defining with the first electrode a spark gap, for initiating from said central region of the combustion chamber combustion of a fuel/air mixture in the combustion chamber.

Abstract: An ultrasonic device for determining the air flow rate in a conduit, comprising a duct, which may form part of the conduit or may be connectable thereto, at each end of which is a respective enlarged cylindrical chamber communicating axially with the duct and housing a respective piezoelectric transducer. In use of the device the piezoelectric transducers both transmit ultrasonic signals towards each other along the duct and the air speed in the duct is determined by the difference in transit times of the ultrasonic signals in the two directions. The air flow through the chambers is largely radial and the piezoelectric transducers are located axially at positions where the air speed is very low to minimize disturbances thereto.

Abstract: An energy dissipator for a vehicle safety belt includes a reel on which one end of the belt is wound and anchored, the reel having two internal screw threads of opposite pitch in which respective bushes are threaded, so that in the event of an unwinding force on the reel due to a tension in the belt, for example on impact, the bushes are screwed towards each other and squash a deformable element interposed between the bushes.

Abstract: An antiskid braking system of the type which includes a threshold circuit which at a first threshold level releases the brakes and at a second threshold level reapplies the brakes according to the deceleration of the vehicle. A correction signal circuit varies the first threshold level in dependence upon or more dynamic parameters of the vehicle such as the wheel speed and/or vehicle deceleration to optimise the anti-skid braking.

Abstract: An anti-skid braking system which includes a throttle control arrangement associated with the throttle plate located in the induction manifold for opening the plate upon operation of the anti-skid system in order to compensate for the braking effect of the engine initiated upon release of the accelerator pedal. The throttle arrangement includes a solenoid-controlled vacuum actuator and a piston connected to the throttle plate through a lever system.