HOSE A 6W0148 - Caterpillar

Illustration 1 g01050367
Block diagram Of The Automatic Retarder Control (ARC) (1) Switch for the Automatic Retarder Control (ARC) (2) CAT Data link (3) Brake/Cooling ECM (4) Retarder On lamp (5) Chassis/Brake valve (6) Supply oil for the parking brake (7) Supply oil for the service brake (8) Engine Output Speed sensor (EOS) (9) On/Off switch for the parking brake (10) Secondary brake pedal and valve (11) Retarder lever (12) Pressure switch for the signal oil from the retarder lever and for the ARC (13) Pressure switch for the signal oil to the service brake/retarder relay valve (14) Service brake pedal and valve (15) Cab brake valve (16) Parking brake solenoid valve (17) Supply solenoid valve for the retarder lever and for the ARC (18) Control solenoid valve for the retarder lever and for the ARC (19) Shuttle valve (20) Pressure switch for the oil from the service brake control
Illustration 2 g00989690
The Automatic Retarder Control system (ARC) is designed to modulate the brakes of a truck during the descent of a grade. The ARC modulates the brake system in order to maintain a constant engine speed. The ARC reduces the effort that is required by the operator in order to maintain a constant engine speed during downhill operation. The constant engine speed improves production and brake cooling.The ARC system engages the service and retarder brakes. If ARC On/Off switch (1) is moved to the On position, the ARC will be activated. The ARC will be activated if the throttle pedal is not depressed and the parking and secondary brakes are Released. The ARC is disabled when the throttle is depressed.The ARC is set at the factory to maintain a constant engine speed of 1950 50 rpm. The engine speed is programmable. When the ARC takes control of the retarding, the engine speed may oscillate out of the speed range for a few seconds. After a few seconds, the speed of the engine should stabilize. In order to correctly operate the ARC, the operator must turn On ARC On/Off switch (1) for the ARC and the operator must then select the correct gear for the grade, load, and ground condition. The ARC is designed to allow the transmission to upshift into the gear that is selected by the shift lever. After the transmission shifts to the gear that is selected by the operator and the engine speed exceeds 1950 rpm, the ARC will apply the retarder in order to maintain a constant engine speed.The ARC system also provides engine overspeed protection. If an unsafe engine speed is reached, the ARC will engage the brakes. This is done even if the switch for the ARC is in the Off position and if the throttle is depressed. A truck that is approaching an overspeed condition will activate a horn and a light at 2100 rpm. If the operator ignores the horn and light the ARC will engage the retarder at 2125 rpm. If the engine speed continues to increase, the Transmission ECM