Electrohydraulic brake system for motor vehicles

• US 20030222497A1
• Filed: 12/18/2002
• Published: 12/04/2003
• Est. Priority Date: 06/20/2000
• Status: Active Grant

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Inventors: Fey, Wolfgang, Klein, Andreas, Engelmann, Mario, Schubert, Peter, Fachinger, Georg
• Granted Patent: US 6,817,681 B2
• Time in Patent Office: Days
• US Class Current: 303/113.1
• CPC Class Codes: B60T 13/686 in hydraulic systems or parts thereof
• CPC Class Codes: B60T 7/06 Disposition of pedal
• CPC Class Codes: B60T 8/321 deceleration B60T8/34, B60T8/52, B60T8/54, B60T8/56, B60T8/58, B60T8/72, B60T8/86, B60T8/88 take precedence
• CPC Class Codes: B60T 8/4081 Systems with stroke simulating devices for driver input B60T8/4077 takes precedence

Abstract

The present invention relates to an electro-hydraulic brake system for motor vehicles which is controllable in a ‘brake-by-wire’ operating mode by the vehicle operator as well as independently of the vehicle operator, and which can be operated in a back-up operational mode where only operation by the vehicle operator is possible. The brake system includes an emergency pressure generator or master brake cylinder which has at least one pressure chamber and is operable by means of a brake pedal, and a hydraulic auxiliary pressure source whose pressure is used to act upon wheel brakes that are connectable to the master brake cylinder by way of at least one hydraulic connection closable by means of a separating valve, as well as an electronic control and regulating unit. In order to achieve a very rapid change-over of the separating valves into the closing position, the present invention arranges for an additional electric circuit that actuates the separating valve independently of the electronic control and regulating unit as the driver'"'"'s deceleration demand occurs.

Claims

1. Electro-hydraulic brake system for motor vehicles which is controllable in a ‘

brake-by-wire’

operating mode by the vehicle operator as well as independently of the vehicle operator, and which can be operated in a back-up operational mode where only operation by the vehicle operator is possible, including

a device for detecting the driver'"'"'s deceleration demand, an emergency pressure generator or, respectively, master brake cylinder that is operable by means of a brake pedal and has at least one pressure chamber,

a travel simulator that cooperates with the master brake cylinder and can be disconnected by actuation of the master brake cylinder,

a hydraulic auxiliary pressure source whose pressure is used to act upon wheel brakes that are connectable to the master brake cylinder by way of at least one hydraulic connection closable by means of a separating valve, as well as

an electronic control and regulating unit,

characterized in that an additional electric circuit (36) is provided which actuates the separating valve (11, 14) independently of the electronic control and regulating unit (32) as the driver'"'"'s deceleration demand occurs.

2. Electro-hydraulic brake system as claimed in claim 1,

characterized in that the reaction time of the electric circuit (36) is considerably shorter than that of the electronic control and regulating unit (32).

3. Electro-hydraulic brake system as claimed in claim 1 or 2,

characterized in that the electric circuit (36) includes an evaluating circuit (40) for detecting the driver'"'"'s deceleration demand (DDD) that serves to enable the actuation of the separating valve (11, 14).

4. Electro-hydraulic brake system as claimed in claim 3,

characterized in that connected downstream of the evaluating circuit (40) is a timer (41) that disables the actuation of the separating valve (11, 14) upon expiry of a predetermined duration.

5. Electro-hydraulic brake system as claimed in claim 3 or 4,

characterized in that a hardware monitoring circuit (watchdog 44) is connected downstream of the electronic control and regulating unit (32), said monitoring circuit disabling the actuation of the separating valve (11, 14) in the event of a dynamic status signal (WD) produced by the electronic control and regulating unit (44) differing from a status signal produced by the hardware monitoring circuit (watchdog 44).

6. Electro-hydraulic brake system as claimed in any one of claims 1 to 5,

characterized in that the actuation of the separating valve (11, 14) is effected by means of two actuation logic circuits (42, 43) being associated with a safety switch (45) and a separating valve driver (46) connected in series with the separating valve (11, 14).