Abstract: An anti-lock braking system comprises a pump motor which is energized initially during vehicle drive-off and then deactivated. The deactivation voltage and subsequent motor voltages are evaluated against predetermined voltage levels for an appropriately operating pump motor to determine whether or not the anti-lock braking system should be deactivated and a failure warning mechanism activated to warn the vehicle operator of the deactivated system.

Abstract: An anti-lock braking system (1) includes an electronic control unit or ECU having software which utilizes inputs of deceleration and pump motor voltage feedback to effect an appropriate duty cycle for the pump motor. By utilizing vehicle velocity, calculated vehicle deceleration and wheel deceleration to estimate the type of surface engaged by the vehicle wheels, and utilizing motor voltage to estimate pump load, the duty cycle of the motor may be varied so that low brake pedal effort braking has the benefit of less pump motor operation and reduced pump motor noise.

Abstract: A pressure piloted release valve (80) is disposed within an adaptive braking system (10) having shuttle valves (34, 44, 54, 64). The release valve (80) provides for a quick release of fluid pressure buildup within the adaptive braking system (10) so that an associated shuttle valve (34, 44, 54, 64) will return to a normal braking position and cease restricting fluid flow with an associated wheel brake (30, 40, 50, 60). The release valve (80) includes a differential area release valve (100) received with a valve body (83) having a stepped bore (90). The valve body (83) includes a frustoconical-shaped body chamber (120) with a radial passage (124) such that displacement of the release valve (100) results in a second end (105) of the release valve (100) engaging sealingly a sloped end wall (102) of the body chamber (120) to prevent fluid flow through a longitudinal through passage (101) of the release valve (100) to a receptacle chamber (85) via the radial passage (124).

Abstract: The pressure differential release valve (130) comprises a three-part body having a first end member (132), an intermediate body member (133), and a second end member (134). The members (132, 133, 134) define an interior stepped bore (139) containing a differential area piston (141) and a poppet (161). The differential area piston (141) and poppet (161) have respective longitudinal through-openings (142, 162) and the poppet (161) engages a valve seat (168) of the body. The longitudinal through-opening (162) of the poppet (161) includes a ball valve (165) biased by a spring (166) into engagement with a valve seat (164) of the poppet (161). The piston (141) abuts the poppet (161) at an end (151) adjacent the valve seat (164) of the poppet (161). Fluid pressure received at an end (135) opening in the first end member (132) is transmitted through the body and exits an end opening (136) at the second end member (134).