KIT-SEAL 1991149 - Caterpillar

Illustration 1 g00996717
Circulation of air through the air starting system
(1) Starting motor solenoid
(2) Relay valve
(3) Lubricator
(4) Pilot valve
(5) Relay valve
(6) Pipe nipple
(7) Starting motor The starting motor and the prelube pump are powered by pressurized air. However, the starting sequence is initiated by an electrical power supply of 24 VDC. The electrical power supply, the wiring, and the electrical controls are provided by the customer.Pressurized air from the main air supply is provided to relay valve (2). The main supply of pressurized air is blocked by the relay valve until the valve opens. The relay valve allows some control air pressure to flow to the valve that is controlled by starting motor solenoid (1).When the normally closed solenoid is activated by 24 VDC, the solenoid opens the connected valve. The valve allows the control air pressure to flow to a piston in the starting motor. The piston causes the starting motor's pinion to engage the flywheel ring gear. The starting motor does not crank the engine yet.The control air pressure flows from the starting motor's piston to the top of relay valve (2). The relay valve opens in order to allow the main supply of pressurized air to flow through lubricator (3).The control air pressure is routed from the top of relay valve (2) to the air inlet at the bottom of pilot valve (4). The control air pressure is not allowed to pass through the pilot valve yet.The main supply of pressurized air bypasses relay valve (5) and the air flows to the prelube pump motor.
Illustration 2 g00996720
Flow of pressurized air and of engine oil through the prelubrication system
(8) Box for the oil pressure switch
(9) Box for the relay
(10) Lubricator
(11) Prelube pump motor
(12) Prelube pump The main supply of pressurized air flows through lubricator (10) in order to operate prelube pump motor (11). The motor operates prelube pump (12). The pump draws engine oil from the oil pan. The oil is pumped upward into the oil cooler's inlet elbow. The oil circulates normally through the engine.A hose is connected from the main oil gallery in the cylinder block to pilot valve (4). When the engine oil pressure reaches 10.3 to 17.2 kPa (1.49 to 2.49 psi), the pilot valve opens. The engine oil pressure indicates that the prelubrication is complete.The control air pressure flows from the air outlet at the bottom of the pilot valve to the top of relay valve (5). The relay valve opens and the main supply of pressurized air flows through pipe nipple (6) in order to operate starting motor (7). The vanes of the starting motor rotate the starting motor's pinion and the pinion rotates the flywheel in order to crank the engine.Another hose is connected from the main oil gallery in the cylinder block to an oil pressure switch in box (8). The customer provides the wiring and an electrical power source for the normally closed switch. Customer supplied wiring connects the switch to a relay coil in box (9). Electrical power to