A system on a tractor for controlling trailer service brakes comprises a manually operated trailer brake switch, a first electropneumatic valve in communication with a pressure source and a controller. The controller has an input communicating with the trailer brake switch, an output communicating with the electropneumatic valve and control logic. The control logic receives an input from the trailer brake switch indicating a driver's request to apply the trailer service brakes of the combination vehicle, determines if a predetermined condition exists and transmits a signal to the output to the electropneumatic valve. The electropneumatic valve transmits pressure to a trailer service control line to actuate the trailer service brakes in response to the trailer brake switch and existence of the predetermined condition.

A device for a hydraulic braking system of a vehicle. The device includes a processing unit, which is programmed to determine at least one brake characteristic value of the hydraulic braking system, the processing unit being programmed to determine the at least one brake characteristic value as a vehicle axle-specific brake characteristic value, which in each case corresponds to a ratio between a brake pressure in all wheel brake cylinders assigned to a shared vehicle axle of the vehicle and a vehicle axle braking torque exerted on the shared vehicle axle with the aid of the wheel brake cylinders. A method for determining at least one brake characteristic value of a hydraulic braking system of a vehicle, and a method for decelerating a vehicle with a hydraulic braking system and an electric motor usable as a generator, are also described.

A vehicle braking system including a control unit (340) which is operable to communicate with at least one sensor (320, 350), the sensor (320, 350) being operable to provide signals corresponding to a characteristic of a vehicle to the control unit (340), and the control unit (340) being in communication with a brake demand source (300) to receive brake demand data, and the control unit (340) also being in communication with a plurality of wheel end units, each wheel end unit including a brake torque control unit (310) which is operable to control an associated brake actuator to apply a braking torque dependent upon a signal received from the control unit (340).

Methods, apparatus, systems and articles of manufacture are disclosed for automatic calibration of electronic trailer brake gain. An example apparatus includes a trailer brake gain calibration module programmed to compare a calculated trailer brake torque to at least one of a first or second threshold, adjust a gain value based upon satisfaction of at least one of the first or second threshold, and apply a pressure to a trailer brake based on the gain value.

System, method, and devices related to a wheel speed sensor that includes a wireless communication device and a motion sensor. The motion sensor includes an accelerometer. The wireless communication device and motion sensor are disposed in a housing. The housing is attached to an attachment member. The attachment member is selectively attached to a wheel of a towed vehicle.

A braking controller and method in a towing vehicle towing one or more towed vehicles as a combination vehicle provides brake control of the one or more towed vehicles based on a level of braking force applied to the towing vehicle. A non-enhanced braking mode applies a first level of braking force to the towed vehicles in a predetermined reduced proportion relative to the level of braking force applied to the towing vehicle, and an enhanced braking mode applies a second level of braking force to the towed vehicles greater than the first level of braking force. The enhanced braking mode strategy is used unless trailer capability information reported by one or more the trailers fails to match against expected trailer capability information.

Techniques of braking a trailer with a trailer braking system. In one example, a controller receives a brake request from a vehicle to apply the trailer braking system, receives a plurality of wheel speed signals from a plurality of wheel speed sensors, and determines a velocity of the trailer based on the plurality of wheel speed signals. The controller determines a wheel speed of one of a plurality of wheels based on one of the plurality of wheel speed signals, compares the velocity of the trailer to the wheel speed to obtain a difference value, and determines that one of the plurality of wheels is unstable when the difference value exceeds a threshold. A braking signal to reduce a braking force on one of the plurality of wheels is generated when one of the plurality of wheels is unstable and when the brake request is received.

Towed vehicles can be extremely heavy. Accordingly, it is too much of a burden to the braking system of a towing vehicle to not have brakes on the towed vehicle. Controlling the brakes of the towed vehicle must be accurately applied otherwise very dangerous conditions can be created. A method of controlling braking of a towed vehicle is, therefore, needed. The method comprises receiving speed signals based on speed of a towing vehicle, or a towed vehicle, or both said towing vehicle and said towed vehicle, receiving pressure signals based on pressure of a hydraulic brake system of the towing vehicle, and generating a brake output signal based on the speed signals and the pressure signals.

A system on a tractor for controlling trailer service brakes comprises a manually operated trailer brake switch, a first electropneumatic valve in communication with a pressure source and a controller. The controller has an input communicating with the trailer brake switch, an output communicating with the electropneumatic valve and control logic. The control logic receives an input from the trailer brake switch indicating a driver's request to apply the trailer service brakes of the combination vehicle, determines if a predetermined condition exists and transmits a signal to the output to the electropneumatic valve. The electropneumatic valve transmits pressure to a trailer service control line to actuate the trailer service brakes in response to the trailer brake switch and existence of the predetermined condition.

A system and method of controlling individual trailer brakes on a towed trailer supporting numerous fault tolerant behaviors including activating each operational brake when a brake is shorted. System operates in multiple modes where it operates with traditional brake controllers, operates in a degraded braking mode without a brake controller and in the preferred mode it retrieves vehicle information from tow vehicle and then communicates with a brake actuator controller over the trailer brake wire. When braking system includes wheel sensors traditional antilock releases are provided and unlike other braking systems this brake actuator controller can maintain wheel speeds below the trailer speed reducing or eliminating periodic wheel releases. System also diagnoses the mechanical operation of the trailer brakes including; identifying when brake adjustment is required, when brake friction surfaces are degrading, as well as diagnosing sensors, braking signals and brake actuator interfaces.