Abstract: A pneumatic vehicle brake system includes first and second groups of wheel brakes belonging, respectively, to first and second brake circuits having first and second compressed air storage tanks for providing first and second stored pressures. At least one first circuit brake cylinder is a combined spring-store/diaphragm cylinder with a spring store part for providing a parking brake and a diaphragm part for providing a service brake. If the first circuit fails, the spring store part is deaerated to engage the parking brake. A pressure sensor for measuring the first stored pressure is connected to a control unit that controls a modulator for aerating and deaerating the spring store part. The control unit generates a signal for an electrically actuatable modulator solenoid valve if the value measured by the sensor falls below a minimum value, such that the spring store part can be aerated and deaerated via the valve.

Abstract: An electropneumatic control arrangement for an automatic vehicle level control system, particularly of a commercial vehicle, includes at least; a solenoid valve unit having at least two electropneumatic solenoid valves, a compressed air inlet for infeeding compressed air, at least one compressed air connection for at least one air bellows and electrical control inputs, and an electronic control unit for actuating the solenoid valve unit. The electronic control unit comprises control outputs for electrically connecting to the control inputs of the solenoid valve unit. A plug connector is configured on the housing of the solenoid valve unit, in which the electrical control inputs are disposed, and a plug connector is provided on the housing of the electronic control unit, in which the control outputs are disposed. The plug connectors are mechanically plugged into each other.

Abstract: A pressure assisted park servo assembly for an automatic transmission includes a servo or spool valve which receives pressurized hydraulic fluid from various sources including two solenoid valves and transmission ports. The servo valve controls two flows of pressurized hydraulic fluid to a servo assembly to place the transmission in or release it from park. The improved park servo assembly exhibits enhanced operating speed.

Abstract: A brake regulation system for motor vehicles is provided with an electronic control unit, by which an automatic parking brake function can be activated in the stationary phase of the motor vehicle and can be deactivated upon reaching a predetermined triggering condition. The control unit can determine in a wheel selective manner the coefficient of friction, or rather the adhesion between the tires and the roadway at the location of the motor vehicle, which is held so as to be stationary by use of the parking brake function. In the presence of different coefficients of friction or adhesion coefficients at the right and left wheel of at least one driven axle, the triggering condition is adapted in the direction of a longer hold of the brake pressure.

Abstract: The invention relates to a pneumatic brake system 72 for a vehicle with brake cylinders 82, 84, which can be actuated with compressed air, for actuating wheel brakes, wherein a first group of wheel brakes belongs to a first brake circuit with a first compressed air storage tank 116 for providing a first stored pressure, and a second group of wheel brakes belongs to a second brake circuit with a second compressed air storage tank 130 for providing a second stored pressure, wherein at least one brake cylinder of the first brake circuit is embodied as a combined spring-store/diaphragm cylinder 84 with a spring store part 86 for providing a parking brake and a diaphragm part 88 for providing a service brake. In the event of a failure of the first brake circuit, the spring store part 86 can be deaerated in order to engage the parking brake.

Abstract: A brake control apparatus includes wheel cylinders which apply braking force to wheels when supplied with hydraulic fluid; a wheel cylinder pressure control system that controls a wheel cylinder pressure independently of a brake operating member operation; a manual hydraulic pressure source that includes first and second hydraulic pressure sources that pressurize the hydraulic fluid; a hydraulic fluid supply path that connects the manual hydraulic pressure source to the wheel cylinders; and a controller. Communication through the hydraulic fluid supply path is interrupted when the wheel cylinder pressure control system controls the wheel cylinder pressure, and the communication is permitted when the wheel cylinder pressure deviates from a target pressure. The controller executes control so that the hydraulic fluid from the first hydraulic pressure source starts to be supplied after the hydraulic fluid from the second hydraulic pressure source starts to be supplied.

Abstract: To retain a vehicle on an inclined roadway and when starting uphill, the vehicle speed, the brake pedal application, the drive torque, the operating condition of the vehicle engine, the application of a parking brake, and the activation of the retaining system is determined. When the retaining system is activated and the vehicle speed lies below a limit value, the brake force or the braking pressure is maintained when the brake pedal is applied and no drive torque is sensed; the brake force is increased when the driving engine is switched off and neither the brake pedal nor the parking brake is activated, or when the engine is switched on and neither brake pedal application nor drive torque is sensed. The brake force is reduced when the parking brake is applied, with the engine switched off and the brake pedal not applied, or a drive torque is sensed with the engine switched on. The retaining system is deactivated when the vehicle speed threshold is exceeded and/or when the off-switch is activated.

Abstract: A motor vehicle is prevented from being parked with an unactivated parking brake. This vehicle has a roll-away preventer normally to apply a brake pressure which prevents the motor vehicle from rolling. To prevent unintentional rolling of the vehicle upon failure of the roll-away preventer, deactivation of the drive engine by using the ignition key is prevented when a brake pressure is not present to prevent the motor vehicle from rolling.

Abstract: A pressure-holding valve for a brake system having a body with a blind bore therein. The body has a first passage which connects the blind bore with a variable pressure inlet port and a pressure outlet port. The blind bore is closed by seals carried on a plug having an axial passage therein connecting said inlet port with a second passage connected to the first passage. A non-return valve is located in said blind bore between the plug and the bottom of the blind bore while a valve controlled by an electromagnet is locate in the plug. In response to an operational signal the valve controlled by the electromagnet is moved into engagement with a seat to interrupt communication between the inlet port and the first passage.