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AssigneeRobert Bosch Technology Corporation
InventorsLarry E. Isakson, John E. Mackiewicz, William Kent Messersmith, Jeffery E. Devall, Michael E. Gatt
Estimating the term…
A back-up power assisted braking system substitutes an intermittently actuated secondary source of pressurized hydraulic fluid such as a traction control/anti-lock pump and motor (41) for the normal braking power assist upon the detection of a failure in the primary power assisted braking system. A failure may be detected in responsive to sensing simultaneous brake pedal (23) displacement and a lack of fluid flow for providing an abnormality signal. Also, a failure may be detected by sensing a predetermined difference between the commanded braking force (45) and the actual braking forces (38, 49). There is a pressure transducer (45) which provides an indication of brake pedal commanded braking force and a hydraulic circuit (43, 53 or 55, 51) interconnecting the secondary source outlet, the individual wheel brake actuators (14) and secondary source inlet. A normally open solenoid operated valve (31, 47) is interposed in the hydraulic circuit between the wheel brake actuators and the secondary source inlet, and a control arrangement is coupled to the pressure transducer to provide an output voltage for enabling the solenoid of the solenoid operated hydraulic valve having a magnitude which varies directly as the indicated operator commanded braking force. Thus, the voltage level determines the braking force during back-up braking.
In a vehicle of the type having a brake pedal commanded hydraulic power assisted braking system including a primary source of pressurized hydraulic fluid, a plurality of individual hydraulic wheel brake actuators (14) and an intermittently actuated secondary source of pressurized hydraulic fluid (41) of a type having a high pressure outlet and a low pressure inlet, a back-up power assisted braking system comprising means (38, 45, 49) for sensing an abnormality in the power assisted braking system and for providing an signal indicative of a sensed abnormality, a pressure transducer (45) providing an indication of brake pedal commanded braking force, a hydraulic circuit (43, 53 or 55,51) interconnecting the secondary source outlet, wheel brake actuators (14) and secondary source inlet, a normally open solenoid operated valve (31, 47) interposed in the hydraulic circuit between the wheel brake actuators and the secondary source inlet, and control means (33) coupled to the pressure transducer and providing an output voltage for enabling the solenoid of the solenoid operated hydraulic valve having a magnitude which varies directly as the indicated operator commanded braking force.
In a vehicle of the type having a hydraulic power assisted braking system including a primary source of pressurized hydraulic fluid (11, 29) and an anti-lock braking feature including an intermittently actuated secondary source of pressurized hydraulic fluid (41) normally actuated only during one of and anti-lock operation and a traction control operation, the improvement comprising:
In a vehicle of the type having a hydraulic power assisted braking system including a primary source of pressurized hydraulic fluid (11, 29) and an anti-lock braking feature including an intermittently actuated secondary source of pressurized hydraulic fluid (41) normally actuated only during one of and anti-lock operation and a traction control operation, the improvement comprising:
In a vehicle of the type having a hydraulic power assisted braking system including a primary source of pressurized hydraulic fluid (11, 29) and an anti-lock braking feature including an intermittently actuated secondary source of pressurized hydraulic fluid (41) normally actuated only during one of and anti-lock operation and a traction control operation, the improvement comprising:
Dependencies are inferred from the claim text.