| 摘要 |
PCT No. PCT/GB94/01681 Sec. 371 Date May 3, 1996 Sec. 102(e) Date May 3, 1996 PCT Filed Aug. 1, 1994 PCT Pub. No. WO95/03963 PCT Pub. Date Feb. 9, 1995A vehicle anti-lock braking (ABS) system having a motor-driven pump (10) for providing a hydraulic supply to the ABS system. The pump motor (10) is controlled by a series device in the form of an electronic switch (16), such as a MOSFET, to enable frequent testing of the motor circuit by short pulses which produce no significant noise. Feedback to control motor speed is obtained by measuring the e.m.f. generated by the motor (16) after it has been switched off and after a delay to allow the back e.m.f., caused by switching off the motor, to decay (preferably to zero) before the measurement operation begins. The generated voltage is integrated during a motor switch-off period, the motor speed being established in this period by subtracting the measured integrated voltage when acting as a generator from the main supply voltage (B+) . The ignition switch-controlled supply within the vehicle electrical system only operates a logic gate (40) to control the supply of direct battery power to the vehicle voltage regulator (36), the pump motor circuit and its electronic controller (16) being connected directly to the battery supply (B+) whereby to act as an energy sink to protect all silicon devices in the electrical control system except the ignition circuit logic gate means.
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