초록 ▼

An electro-hydraulic brake apply system includes an emulator that effects pedal feel simulation by allowing compliance at a selective variable rate. This provides a vehicle driver with the preferred pedal travel and feedback characteristics of a conventional master cylinder/power booster apply syste

An electro-hydraulic brake apply system includes an emulator that effects pedal feel simulation by allowing compliance at a selective variable rate. This provides a vehicle driver with the preferred pedal travel and feedback characteristics of a conventional master cylinder/power booster apply system. As a secondary function, the emulator is utilized to latch the modulator. This locks the modulator apply piston in place when electrical power is removed from the drive motor. Further, the emulator operates to hydraulically isolate the master cylinder from the wheel brakes during normal system operation.

대표청구항 ▼

[ What is claimed is:] [1.] A brake apply system for delivering fluid pressure to a wheel brake to selectively actuate the wheel brake in two separate modes of operation comprising:a master cylinder wherein fluid pressure is generated in the master cylinder in response to a manual input on a brake p

[ What is claimed is:] [1.] A brake apply system for delivering fluid pressure to a wheel brake to selectively actuate the wheel brake in two separate modes of operation comprising:a master cylinder wherein fluid pressure is generated in the master cylinder in response to a manual input on a brake pedal;an emulator, wherein the emulator has a bore with a piston slidably carried in the bore, with a spring biasing the piston toward an end of the bore wherein a first chamber is defined in the bore on a first side of the piston and a second chamber is defined in the bore on a second side of the piston wherein the piston is spool shaped with a land of the piston adjacent each of the first and second chambers wherein a third chamber is defined between the lands and wherein the emulator includes a groove providing an opening between the first and third chambers when the piston is in an at-rest position;a first conduit extending between the master cylinder and the first chamber;a pressure transducer positioned in the first conduit;a wheel brake;a second conduit extending between the third chamber and the wheel brake so that a first mode of operation is provided wherein the first mode of operation is characterized by actuation of the wheel brake with fluid pressure generated by the master cylinder and delivered to the wheel brake through the first conduit, the emulator and the second conduit;a modulator having a variable chamber;a third conduit extending between the variable chamber and the wheel brake so that a second mode of operation is provided wherein the second mode of operation is characterized by actuation of the wheel brake with fluid pressure generated by the modulator and delivered to the wheel brake through the third conduit in relation to the a pressure resulting in the first conduit and sensed by the pressure transducer;a fourth conduit extending between the second chamber and the modulator; anda normally closed valve positioned in the fourth conduit.