Robert Boschgmbh

Wenguang Zhou

Rosalin Irwan

Quingyuan Li

Qingyuan Li

Labiba Quaiyum

Bertram Foitzik

Hsien-cheng Wu

Ravikumar Bhadange

Fu-Long Chang

Reimar Fuchs

Kevin Wu

A system and method for generating a pressure-volume curve for a hydraulic system in a vehicle. The system includes a plunger coupled to the hydraulic system, a pressure sensor configured to detect a pressure of the hydraulic system, and an electronic controller configured to access a prior pressure-volume curve from a memory, generate a signal to move the plunger, receive a pressure from the pressure sensor, generate a new pressure-volume curve based upon the received pressure and a position of the plunger, compare the new pressure-volume curve to the prior pressure-volume curve, in response to the new pressure-volume curve and the prior pressure-volume curve differing by at least a threshold value, replace the prior pressure-volume curve with the new pressure-volume curve in the memory, and actuating the hydraulic system based upon the stored pressure-volume curve.

Real-time pressure-volume curve generation for a hydraulic system

A system and method for performing a diagnostic on a hydraulic system in a vehicle while the vehicle is at a standstill. The method includes, by means of an electronic processor, moving a plunger at a constant rate, determining a position of the plunger, receiving a pressure of the hydraulic system from a pressure sensor, comparing the determined position and the measured pressure to a position versus pressure graph, and sending a diagnostic to a diagnostic indicator.

Performing a diagnostic on a hydraulic system while the vehicle is operating

A vehicle includes a brake pedal, a master cylinder, a braking circuit with a wheel cylinder, and a brake pressure generator with strokable piston. A pedal feel simulator is coupled to the master cylinder through a switchable valve, the simulator providing a reaction force. An isolation valve closes to isolate the braking circuit from the master cylinder and the simulator circuit. A controller is programmed to place the simulator in fluid communication with an output of the brake pressure generator, and to stroke the piston at a designated diagnostic time. The resulting pressure increase is observed, and the controller checks whether the pressure-increase to piston-stroke relationship is within a predetermined acceptable range for continued operation of a brake-by-wire mode in which the master cylinder is coupled to the simulator circuit and decoupled from the braking circuit.

Vehicle having brake system and method of operating

A brake system comprises a master cylinder, a first brake cylinder, a second brake cylinder, an electronically-controlled pressure generating unit distinct from the master cylinder, a first hydraulic circuit in selective fluid communication with the master cylinder and the first brake cylinder, a second hydraulic circuit in selective fluid communication with the master cylinder and the second brake cylinder, and a controller. In a first mode, the controller is operable to actuate the electronically-controlled pressure generating unit to deliver hydraulic fluid pressure to the first brake cylinder and the second brake cylinder proportional to an input. In a second mode, the controller is operable to actuate the electronically-controlled pressure generating unit to deliver hydraulic fluid pressure to the first hydraulic circuit and the first brake cylinder and the master cylinder is in communication with the second hydraulic circuit to deliver hydraulic fluid pressure to the second brake cylinder.

Vehicle brake system and method of operating

A vehicle includes a brake pedal, a master cylinder, a braking circuit with a wheel cylinder, and a brake pressure generator with strokable piston. A pedal feel simulator is coupled to the master cylinder through a switchable valve, the simulator providing a reaction force. An isolation valve closes to isolate the braking circuit from the master cylinder and the simulator circuit. A controller is programmed to connect the simulator circuit with an outlet of the brake pressure generator, and to stroke and retract the piston at a designated diagnostic time. The controller observes a pressure decrease as the piston retracts and checks whether the pressure-decrease to piston-retraction relationship is within a predetermined acceptable range for continued operation of a brake-by-wire mode in which the master cylinder is coupled to the simulator circuit and decoupled from the braking circuit.

A vehicle braking system includes a brake pedal, master cylinder, a braking circuit with a wheel cylinder, and a brake pressure generator. A pedal feel simulator is coupled to the master cylinder output side through a switchable valve, the pedal feel simulator providing a reaction force. An isolation valve closes to isolate the braking circuit from the master cylinder and the simulator circuit. A primary pressure sensor generates a braking request signal responsive to the brake pedal. A controller activates the brake pressure generator to apply a braking force to the wheel cylinder based on the braking request signal. The controller identifies an abnormal value from the primary pressure sensor and couples the pedal feel simulator with a secondary pressure sensor within the braking circuit to determine whether the abnormal value indicates a primary pressure sensor malfunction or a malfunction of the pedal feel simulator or the switchable simulator valve.

Brake system and method of operating

A vehicle includes a brake pedal, a master cylinder, a braking circuit with a wheel cylinder, and a brake pressure generator. A pedal feel simulator is coupled to the master cylinder through a switchable valve. An isolation valve is provided to isolate the braking circuit from the master cylinder and the simulator circuit. A controller is programmed to couple the simulator circuit to a pressure sensor positioned in the braking circuit at a designated diagnostic time during which the brake pedal is depressed to generate a brake pedal input while the vehicle is positively parked. Increased fluid pressure from the brake pedal input is observed with the sensor in the braking circuit. The controller checks whether the pressure-increase to brake pedal input relationship indicates efficacy of the simulator circuit for continued operation of brake-by-wire operation.

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Novi, MI, United States of America

Wenguang Zhou