Patent GB-1331395-A (GB)
Title: Electrical control system for a motor vehicle
Inventor: RIDDOCH H
IPC: B60T17/22
Filed: 1972-06-28
Abstract: 1331395 Electrical control; braking systems; anti-locking systems GIRLING Ltd 28 June 1972 [3 July 1971] 31260/71 Headings F2E and F2F [Also in Division B7] A motor vehicle has an electrical starting system 1 with an ignition switch I incorporating a starter switch S, and a starter motor M, the vehicle also including an hydraulic braking system with an electric pump B and an hydraulic brake anti-locking system 3 with an electric pump C the pumps B, C supplying accumulators A 2 , A 1  respectively: operation of motor M and pumps B, C is controlled by output signals from a logical control section 4 which operates in response to input signals from systems 1, 2, 3 and from the vehicle alternator 5 such that the motor M and pumps B, C operate one at a time and according to predetermined operating priorities where there is a demand for two or more of these devices to operate at the same time. As shown, the system 2 includes two pressure responsive switches P1, P2-pressure switch P1 closes below a first predetermined minimum level (say 1200 lb in<SP>2</SP>) and pressure switch P2 closes at pressures below a higher predetermined minimum level (say 2500 lb in<SP>2</SP>). The antilocking system 3 comprises three hydraulically operated modulators W1, W2, W3 the first two of which control operation of the brakes on the front wheels independently of one another, and the third of which controls operation of the brakes on the rear wheels of the motor vehicle. Individual switches T are connected to the modulators, and are triggered to supply signals to the logical section 4 when the actuators require fluid as a result of pressure drop-the control section 4 produces a signal to energize a relay R4 to operate pump C. The alternator 5 comprises a warning light control unit G acting as a switch and a relay R10 so that a signal is supplied to the logical control section 4 when the alternator is charging. When the ignition switch I is operated relays R1 and R2 are energized and via closed pressure switch P1 and relays R6 and R8 on operating relay R3 of pump B is energized to start the pump B. Simultaneously a relay R9 is energized to prevent operation of the motor M until pressure in the braking system 1 builds up sufficiently to open switch P1 thereby breaking the circuit to relay R3 to stop pump B. The switch S can now be operated to start motor M and start the engine. With the engine running a signal from alternator 5 energizes relay R6 and relay R3 is again energized to start the pump B until pressure builds up sufficiently to open switch P2 and break the circuit to relay R3. All low pressure conditions in the hydraulic braking system 2 are indicated by a warning lamp L. As regards the anti-locking system 3, the modulator switches T may be operable to start the pump C once the ignition switch I has been operated but not while the starter switch S is actually operated. Alternatively the pump C may be given absolute priority over motor M as well as pump B by modifying the ignition switch I and starter switch S and by modifying the logical control section 4 so that the pump C and motor M are interlocked. Preferably in this ease the logical control section 4 comprises electronic gating circuitry.