An electronically controlled brake system includes a brake actuator wherein a valve is electrically controlled to maintain the spring chamber in the non-actuated position during normal operation. However, should there be a failure in the electrical system, then the spring chamber is allowed to set the brake actuator. The "failure" could also include a diagnostic system included in the control which identifies a failure in control operation. In this way, should there be an electrical failure, either in the control or power circuits, the truck is stopped.
Evacuation operation performance is improved when any abnormality occurs in an electronic throttle control system. When any serious abnormality occurs, a first abnormality storage element (133) operates, a load relay for a power supply circuit (104a) of a throttle valve open/close controlling motor (103) is de-energized to operate a first alarm and display (109a). Thus a first device carries out the evacuation operation by a fuel cut control. When any slight abnormality occurs, a second abnormality storing element (136) comes to actuate thereby a second alarm and display (109b) being operated. Thus a second device carries out the evacuation operation using together a throttle valve opening control by the motor 103 and the fuel cut control.
A system is provided for permitting movement of a vehicle having brakes while an auxiliary component of the vehicle is operated by the vehicle. The system includes a pressurized fluid source. A control device is coupled to the pressurized fluid source and the brakes of the vehicle to release the brakes in response to a first signal and to at least partially apply the brakes in response to a second signal. A controller applies the first signal to the control device when at least one of a first set of conditions exist and applies the second signal to the control device when a second set of conditions exist.
The electro-pneumatic latching valve system having an electrical switch unit that further includes an "apply" or "activate" switch, a "release" or "deactivate" switch, and a power supply. A first solenoid valve is in electrical communication with the activate switch and a second solenoid valve is in electrical communication with the deactivate switch. A pneumatic latching valve is in pneumatic communication with the first and second solenoid valves and a source of pressurized control and supply air is in pneumatic communication with the pneumatic latching valve and the solenoid valves. A terminal device, e.g., a spring brake, is in pneumatic communication with the latching valve, and the device is released or applied in response to pressurized supply air delivered to the device through the pneumatic latching valve in response to pneumatic control signals delivered to the pneumatic latching valve from the solenoid valves.
