LATCH AS 3567550 - Caterpillar

Illustration 1 g01021887
Typical example
(1) Brake housing assembly
(2) Bolts
(3) Slave piston
(4) Solenoid valve
(5) Exhaust valve bridges
(6) Stud, spacer and nut The compression brake consists of three identical housing assemblies (1). A brake housing is installed in each of the valve mechanism compartments. The brake is located above the rocker arms and the rocker arm shaft. Each housing assembly is positioned over two cylinders. The housing is mounted to the support for the rocker arm shaft with bolts (2). The housing is supported on the cylinder head with one stud, one spacer, and one nut (6). The exhaust rocker arm is used to transmit force from slave piston (3) to the exhaust valve. A lead wire carries the signal of the compression brake to solenoid valve (4). Each lead wire activates the compression brake on two cylinders of the engine.Note: Only the valve mechanism that is for the exhaust is used in the operation of the compression brake.Note: The slave piston pushes on the rocker arm for the exhaust valves. The rocker arm depresses BOTH exhaust valves of each cylinder during the operation of the compression brake.The control circuit for the compression brake provides progressive braking capability. The control circuit for the compression brake permits the operation of one, two, or all three of the compression brakes. Therefore, the compression brake can be activated on two cylinders, four cylinders, or six cylinders of the engine.Compression Brake Operation
Illustration 2 g01023115
Master-slave circuit schematic
(1) Ground wire
(2) Solenoid valve
(3) Lead wire from the ECM
(4) Lead wire to the sensor for the ECM
(5) Spring
(6) Control valve
(7) High pressure oil passage
(8) Slave piston adjustment screw
(9) Slave piston
(10) Master piston
(11) Oil passage in the rocker arm shaft
(12) Engine oil pump
(13) Spring
(14) Rocker arm for the electronic unit injector
(15) Engine oil pan
(16) Oil drain passage
(17) Low pressure oil passage
(18) Ball check valve
(19) Exhaust valve bridge
(20) Exhaust valves
(21) Rocker arm for the exhaust valve
(22) Camshaft The compression brake operates on engine oil. The engine oil is supplied around the bolts through the rocker arm shafts. Solenoid valve (2) controls the oil flow in the compression brake housing assembly.The solenoid is activated by a signal from the ECM. Solenoid valve (2) moves down when the compression brake is activated. Solenoid valve (2) closes oil drain passage (16) to engine oil pan (15). Solenoid valve (2) also opens low pressure oil passage (17) to control valve (6). As low pressure oil passage (17) is filled with engine oil, the control valve is pushed up in the chamber against the force of spring (5). In the up position, a groove in control valve (6) is in alignment with high pressure oil passage (7) that supplies slave piston (9) and master piston (10). The engine oil pressure will now lift ball check valve (18). High pressure oil passage (7) is filled with the engine oil from passage (17). The chambers behind the slave piston and the master piston are also filled. This pressure moves the master piston downward until contact is made with electronic unit