ENGINE AR 4P6893 - Caterpillar

Illustration 1 g03661833
One-Way / One or Two Pump - Electronic Control
(1) Tool relief valve
(2) Main control valve
(3) Flow limit 1 pressure sensor
(4) Proportional reducing valve (Flow limit 1)
(5) Proportional reducing valve (Flow limit 2)
(6) Flow limit 2 pressure sensor
(7) Proportional reducing valve (A2 extend)
(8) Proportional reducing valve (A1 extend)
(9) Left joystick (stick)
(10) Right joystick (boom)
(11) F2.2 stack valve
(12) Tool line relief valve
(13) Attachment control valve
(14) Attachment control valve
(15) Tool line relief valve
(16) Hydraulic oil cooler
(17) Boom DOWN control pressure sensor
(18) Boom UP control pressure sensor
(19) Stick IN control pressure sensor
(20) Stick OUT control pressure sensor
(21) Pilot manifold
(22) Main relief valve
(23) Hydraulic tank
(24) Pilot relief valve
(25) Idler pump
(26) Drive pump
(27) Pilot pump
(28) Proportional reducing valve (power shift pressure) One-Way / One or Two Pump with electronic control is designed to allow complete electronic control over the work tool. This hydraulic system allows the operator to control a work tool with a one-way flow system with from one pump or two pumps.One-Way Flow from One Pump
One-way flow from one pump can be achieved by selecting a work tool that requires one-way flow from one pump. The work tool can be selected through the monitor or by the work tool select switch. A typical example is a hammer that receives oil from one pump only.When one pump flow is required to the work tool, the pump supplying the oil can be programmed through the monitor. The following situations are listed to increase controllability of the work tool.
When the work tool with a boom and bucket operation is used most often, the idler pump is recommended as the supply pump.
When the work tool with a stick and swing operation is used most often, the drive pump is recommended as the supply pump.Reference: Refer to Testing and Adjusting, "Work Tool Parameter - Program" for the tool control system to change the settings for work tool operation.Reference: Refer to Testing and Adjusting, "One-Way / One or Two Pumps - Electric Control: Default Value of Work Tool Parameters" for the Tool Control System to reference the factory settings.
Table 1
Operation Lever List
Control Extension
Right joystick thumb wheel Push Forward
Illustration 2 g03662268
One-Way Flow from One Pump (idler pump)
(1) Tool relief valve
(4) Proportional reducing valve (Flow limit 1)
(5) Proportional reducing valve (Flow limit 2)
(7) Proportional reducing valve (A2 extend)
(11) F2.2 stack valve
(13) Attachment control valve
(14) Attachment control valve
(23) Hydraulic tank
(25) Idler pump
(26) Drive pump
(27) Pilot pump The following description is made under the assumption that the idler pump is supplying oil to the work tool.When the device for activation listed in Table 1 is pressed, the machine ECM sends a modulated signal to proportional reducing valve (15). Proportional reducing valve (7) allows pilot oil to flow to attachment control valve (14). Attachment control valve (14) shifts, allowing high-pressure oil from the idler pump to flow to the work tool.When abnormally high pressure occurs in the line to the work tool, tool relief valve (1) opens at a set pressure. This opening will allow the high-pressure oil into the return system and