Method for adjusting brake pressures of a vehicle, and brake system for carrying out the method
AssigneeWABCO GmbH
InventorHorst Eckert
Life of this patent
Estimating the term…
Abstract
A method for adjusting brake pressures at pneumatically actuated wheel brakes of a vehicle includes, after an external braking demand, continuously ascertaining, by a brake control unit, in a pressure control mode, at least one differential slip value from measuring signals supplied by speed sensors of the wheels, as the difference between the slip of two axles of the vehicle before releasing the control signals; evaluating the differential slip value with consideration for a predefined or adjustable setpoint differential slip value; and depending on the evaluation, bringing the differential slip value closer to the setpoint differential slip value by adapting at least one control signal.
Claims24
A method for adjusting brake pressures at pneumatically actuated wheel brakes of a vehicle, wherein the brake pressures at the wheel brakes are adjusted in a normal braking mode depending on a driver's braking demand determined by a driver of the vehicle, and wherein, when an external braking demand independent of the driver's braking demand is received and/or when certain wheels tend to lock, a brake control unit takes over adjustment of the brake pressures in a pressure control mode, wherein the brake control unit, in the pressure control mode, ascertains control signals for pressure control valves of the particular wheel brakes and changes the brake pressures of the relevant wheel brake by controlling the pressure control valves, the method comprising:
- after an external braking demand, continuously ascertaining, by the brake control unit, in the pressure control mode, at least one differential slip value from measuring signals supplied by speed sensors of the wheels, as the difference between the slip of two axles of the vehicle before releasing the control signals;
- evaluating the differential slip value with consideration for a predefined or adjustable setpoint differential slip value;
- and
- depending on the evaluation, bringing the differential slip value closer to the setpoint differential slip value by adapting at least one control signal,
- wherein the brake control unit evaluates the at least one ascertained differential slip value with consideration for at least one control intervention criterion and, depending on fulfillment of the at least one control intervention criterion, releases the control signals or adapts at least one control signal for readjusting the differential slip value, and
- wherein at least one slip threshold value is specified to the brake control unit as a control intervention criterion for evaluation of the differential slip value and, if the slip threshold value is exceeded, an adaptation of the distribution of brake pressure to the axles takes place.
A method for adjusting brake pressures at pneumatically actuated wheel brakes of a vehicle, wherein the brake pressures at the wheel brakes are adjusted in a normal braking mode depending on a driver's braking demand determined by a driver of the vehicle, and wherein, when an external braking demand independent of the driver's braking demand is received and/or when certain wheels tend to lock, a brake control unit takes over adjustment of the brake pressures in a pressure control mode, wherein the brake control unit, in the pressure control mode, ascertains control signals for pressure control valves of the particular wheel brakes and changes the brake pressures of the relevant wheel brake by controlling the pressure control valves, the method comprising:
- after an external braking demand, continuously ascertaining, by the brake control unit, in the pressure control mode, at least one differential slip value from measuring signals supplied by speed sensors of the wheels, as the difference between the slip of two axles of the vehicle before releasing the control signals;
- evaluating the differential slip value with consideration for a predefined or adjustable setpoint differential slip value;
- and
- depending on the evaluation, bringing the differential slip value closer to the setpoint differential slip value by adapting at least one control signal,
- wherein the brake control unit evaluates the at least one ascertained differential slip value with consideration for at least one control intervention criterion and, depending on fulfillment of the at least one control intervention criterion, releases the control signals or adapts at least one control signal for readjusting the differential slip value, and
- wherein a tolerance range comprising an upper slip threshold value and a lower slip threshold value is specified to the brake control unit as a control intervention criterion for the evaluation of the differential slip value and, if the upper slip threshold value is exceeded or the lower slip threshold value is fallen below, an adaptation of the distribution of brake pressure to the axles takes place.
A method for adjusting brake pressures at pneumatically actuated wheel brakes of a vehicle combination including a motor vehicle and at least one towed vehicle, wherein the brake pressures at the wheel brakes are adjusted in a normal braking mode depending on a driver's braking demand determined by a driver of the vehicle, and wherein, when an external braking demand independent of the driver's braking demand is received and/or when certain wheels tend to lock, a brake control unit takes over adjustment of the brake pressures in a pressure control mode, wherein the brake control unit, in the pressure control mode, ascertains control signals for pressure control valves of the particular wheel brakes and changes the brake pressures of the relevant wheel brake by controlling the pressure control valves, the method comprising:
- after an external braking demand, continuously ascertaining, by the brake control unit, in the pressure control mode, at least one differential slip value from measuring signals supplied by speed sensors of the wheels, as the difference between the slip of two axles of the vehicle before releasing the control signals;
- evaluating the differential slip value with consideration for a predefined or adjustable setpoint differential slip value;
- and
- depending on the evaluation, bringing the differential slip value closer to the setpoint differential slip value by adapting at least one control signal,
- wherein differential slip values are determined for multiple axles, in each case based on a reference axle taken into account in all axle pairs, and
- wherein a trailer axle having a least slip at the moment is continuously determined at a present control axle from measuring signals of speed sensors of wheels of the towed vehicle,
- wherein a trailer differential slip value is ascertained for the control axle according to the difference of the slip of the reference axle of the motor vehicle and the slip of the control axle of the towed vehicle and is brought closer to the setpoint differential slip value by adjusting a trailer brake pressure, and
- wherein at wheel brakes of the remaining trailer axles that differ from the control axle, the inlet valves of respective pressure control valves are closed after a start point according to the requirement of the external braking demand.
A braking system of a motor vehicle or a vehicle combination including a motor vehicle as the towing vehicle and at least one towed vehicle, the braking system comprising:
- one brake cylinder and one pressure control valve per wheel, which are connected to a brake control unit in a signal-transmitting manner in order to receive control signals during a pressure control mode,
- a service-brake valve which can be actuated by a driver of the vehicle, and
- a brake signal emitter,
- wherein the brake control unit is configured to adjust brake pressures in the brake cylinders in a normal braking mode, depending on a driver's braking demand, by actuating the service-brake valve
- wherein the brake control unit is configured to adjust brake pressures in the brake cylinders in a pressure-control mode, via the pressure control valves,
- wherein the brake control unit is configured to receive external braking demands which are independent of the driver's braking demand,
- wherein the brake control unit is connected to speed sensors of the wheels for detecting rotational behavior and for monitoring a tendency of the wheels of the vehicle to lock based on measuring signals of the speed sensors and, upon determination of a tendency of at least one wheels to lock and/or upon reception of an external braking demand, to take over adjustment of the brake pressures in the pressure control mode,
- wherein the brake control unit is configured for continuously determining differential slip values from the measuring signals of the speed sensors as differences between slips of two axles of the vehicle and for evaluating and readjusting the differential slip value according to one predefined or ascertained setpoint differential slip value by adapting the control signals,
- wherein the brake control unit is configured to evaluate the at least one ascertained differential slip value with consideration for at least one control intervention criterion and, depending on fulfillment of the at least one control intervention criterion, releases the control signals or adapts at least one control signal for readjusting the differential slip value, and
- wherein at least one slip threshold value is specified to the brake control unit as a control intervention criterion for evaluation of the differential slip value and, if the slip threshold value is exceeded, an adaptation of the distribution of brake pressure to the axles takes place.
Dependencies are inferred from the claim text.