ENGINE AR-COMPLETE 2615341 - Caterpillar

Illustration 1 g02289058
Partial hydraulic schematic (1) Main control valve (2) Pilot control valve (boom and bucket) (3) Pilot control valve (stick and swing) (4) Pilot control valve (blade) (5) Pilot pump (6) Main hydraulic pump (7) Pilot manifold (8) Hydraulic activation solenoid valve (9) Travel speed solenoid valve (10) Pilot relief valve (11) Pilot control valve (travel) (12) Pilot control valve (swing boom)
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Operators compartment (13) Left joystick (stick and swing) (14) Joystick thumbwheel for the swing boom (15) Left travel lever (16) Right travel lever (17) Right joystick (boom and bucket) (18) Blade control leverPilot pump (5) is a gear pump that supplies oil flow to the pilot system. The pilot pump is located inside the main pump compartment and mounted externally to main pump (6). The pilot pump shaft is mechanically connected to the main hydraulic pump shaft.The pressure of the pilot system is limited by pilot relief valve (10) located in pilot manifold (7). The pilot relief valve pressure setting is adjustable.Pilot oil performs the following functions:Operation of the main control valve - When joysticks (13) and (17) are operated, pilot oil is sent to main control valve (1) via pilot control valve (2) and pilot control valve (3). The boom swing is activated by the joystick thumbwheel for swing boom (14). Pilot oil is sent to main control valve (1) via pilot control valve (12) in order to perform a swing boom function. The blade cylinder is activated by pilot control lever (18). The pilot oil is sent to main control valve (1) via pilot control valve (4) in order to perform a blade function. When travel levers (15) and (16) are operated, pilot oil is sent to main control valve (1) via pilot control valve (11) .Generation of signal pressure - The following operations are carried out by the signal pressure that is generated in the pilot circuit:
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(19) Hydraulic activation control lever
Hydraulic activation control lever (19) controls solenoid valve (8). When hydraulic activation control lever (19) is placed in the UNLOCKED position, solenoid valve (8) is energized and pilot oil passes through the solenoid valve. Pilot oil now flows to the pilot control valves. When the hydraulic activation control lever is shifted to the LOCKED position, solenoid valve (8) of pilot oil manifold (7) is not energized. Pilot oil is not supplied to the pilot control valves. Thus when the joysticks and/or the travel levers/pedals are operated, the cylinders or the motors are not activated.
The swing parking brake is released. Anytime the boom swing control valve, swing control valve, stick control valve, bucket control valve, or boom control valve is shifted the swing parking brake is released.ReferenceFor more information concerning the swing parking brake, refer to Systems Operation, "Swing Hydraulic System".
When the travel speed switch on the right console is set at the HIGH SPEED position, travel speed solenoid valve (9) opens. This action allows pilot oil to flow through travel speed solenoid valve (9). The oil then flows to the displacement change