Brake system including anti-lock control and electronic brake force distribution
First Claim
1. A brake control system for a vehicle having front wheels and rear wheels, said brake system comprising:
- a plurality of control valves for controlling pressure fluid at brakes associated with the front and rear wheels of the vehicle, including at least one rear-wheel brake inlet valve for controlling pressure fluid flow to a first rear-wheel brake associated with a first rear wheel of the vehicle and a second rear-wheel brake associated with a second rear wheel of the vehicle;
a switch responsive to at least one of;
(a) braking pressure when a predetermined pressure threshold in a master cylinder in the vehicle is exceeded, and(b) a measured quantity related to vehicle dynamics;
control electronics responsive to wheel sensor signals representative of the rotational behavior of the wheels of the vehiclefor generating valve control signals for controlling each of the plurality of control valves;
error monitoring means for detecting the occurrence of defects and malfunctions in said control electronics and for deactivating selected ones of said plurality of control valves other than said rear-wheel brake inlet valve; and
a secondary circuit, which remains operative after defects and malfunctions in said control electronics are detected, for controlling said rear-wheel brake inlet valve to maintain pressure in the first and second rear-wheel brakes at a limited level in response to said switch and to deactivation, by said error monitoring means, of selected ones of said plurality of control valves.
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Accused Products
Abstract
A brake system including electronic anti-lock control (ABS) and electronically controlled brake force distribution (EBV). This brake system has electrically operable hydraulic valves, of which the inlet valves are open in their inactive position. An electronic error monitoring device is provided which responds upon the occurrence of defects or malfunctions and disconnects the control at least in part. The brake system also has control electronics including secondary circuits which remain in function after the error monitoring device has responded, and by which the inlet valves leading to the rear-wheel brakes are actuated and which are provided such that the pressure in the rear-wheel brakes is maintained constant when a limit value of the braking pressure in the master cylinder is exceeded.
12 Citations
23 Claims
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1. A brake control system for a vehicle having front wheels and rear wheels, said brake system comprising:
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a plurality of control valves for controlling pressure fluid at brakes associated with the front and rear wheels of the vehicle, including at least one rear-wheel brake inlet valve for controlling pressure fluid flow to a first rear-wheel brake associated with a first rear wheel of the vehicle and a second rear-wheel brake associated with a second rear wheel of the vehicle; a switch responsive to at least one of; (a) braking pressure when a predetermined pressure threshold in a master cylinder in the vehicle is exceeded, and (b) a measured quantity related to vehicle dynamics; control electronics responsive to wheel sensor signals representative of the rotational behavior of the wheels of the vehicle for generating valve control signals for controlling each of the plurality of control valves; error monitoring means for detecting the occurrence of defects and malfunctions in said control electronics and for deactivating selected ones of said plurality of control valves other than said rear-wheel brake inlet valve; and a secondary circuit, which remains operative after defects and malfunctions in said control electronics are detected, for controlling said rear-wheel brake inlet valve to maintain pressure in the first and second rear-wheel brakes at a limited level in response to said switch and to deactivation, by said error monitoring means, of selected ones of said plurality of control valves. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A brake system including:
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electronic anti-lock control (ABS) and electronically controlled brake force distribution (EBV) by means of electrically operated hydraulic valves of which the inlet valves controlling the pressure fluid flow to individual wheel brakes are open in their inactive position, control electronics to generate valve control signals in response to wheel sensor signals representative of the rotational behavior of the individual wheels, and an error monitoring device which responds upon the occurrence of defects or malfunctions and disconnects or deactivates the control at least in part, characterized in that; (a) the brake system further includes; (1) voltage supply, (2) a logic circuit, (3) a pressure switch responsive to hydraulic pressure in the master cylinder, and (4) a switch responsive to vehicle acceleration; (b) the control electronics include secondary circuits which; (1) remain operative after response of the error monitoring device for controlling the inlet valve leading to the rear-wheel brakes, and (2) are provided such that the pressure in the rear-wheel brakes is maintained constant or limited in dependence on at least one of; (i) the braking pressure, (ii) when a predetermined pressure threshold in the master cylinder is exceeded, and (iii) a measured quantity related to vehicle dynamics, (3) include a driver for actuating the inlet valves leading to the rear-wheel brakes, the driver being actuated by the control electronics by way of the logic circuit only if the voltage supply is disconnected from the other hydraulic valves and the pressure switch, operated by the hydraulic pressure in the master cylinder, or a switch responding to the vehicle acceleration is operated; and (c) the hydraulic valves, with the exception of the inlet valves leading to the rear-wheel brakes, are connected to the voltage supply by way of a mechanic or electronic disconnecting relay which is; (1) controlled by the error monitoring device, and (2) on detection of malfunction, interrupts the voltage supply of the hydraulic valves. - View Dependent Claims (21, 22, 23)
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Specification