RELAY AS 1443996 - Caterpillar

Illustration 1 g03667372
Schematic for the engine lubrication system
(1) Engine oil coolers
(2) Engine oil filters
(3) High-pressure fuel pump
(4) Turbochargers
(5) Turbocharger mounting support
(6) Front gear train
(7) Engine block
(8) Pressure relief valve for the lubrication system
(9) Engine oil cooler bypass valve
(10) Engine oil pump
(11) Prelubrication pump
(12) Engine oil pan
(13) Pressure regulator valve for the lubrication system
(14) Suction screen
Illustration 2 g03667374
Engine block lubrication (typical example)
(15) Main oil galleryEngine oil pump (10) is a gear-type pump that generates pressure for the engine lubrication system. The engine oil pump is mounted on the back side of the front gear housing. The pump gears are driven by the front gear train. Oil is drawn into the inlet of the pump through suction screen (14). Oil is drawn through the suction screen through a suction tube to the oil pump.Pressure regulator valve (13) is mounted to the engine oil pump. The pressure regulator valve controls the engine oil pressure to 600 100 kPa (87 15 psi) at the rated speed of the engine. In the case of a problem with the pressure regulator valve, pressure relief valve (8) limits the maximum pressure in the lubrication system to 850 kPa (123 psi). Both of the valves return excess engine oil to engine oil pan (12).The pressurized oil is directed through engine oil coolers (1). The engine oil coolers lower the temperature of the engine oil before the engine oil is sent to the filters. If the oil coolers become restricted, engine oil cooler bypass valve (9) allows engine oil to bypass the oil coolers. If the pressure differential across the oil coolers exceeds 180 kPa (26 psi), the bypass valve will allow engine oil to bypass the oil coolers. The oil coolers are mounted to the left side of the engine.Engine oil filters (2) are used to clean the engine oil. Cartridge-type filters are used. The filters are located on the front of the engine. Clean engine oil from the filters flows through an oil line and into the main oil gallery (15) that is cast into engine block (7). The main oil gallery supplies oil to the camshaft bearings through drilled passages in the engine block. The engine oil flows around each camshaft journal to the cam followers. The engine oil travels to each cylinder head through additional drilled passages. Passages that travel to the lifter groups lubricate the valve lifters. There are also passages in the cylinder heads that provide lubrication of the rocker arms, rocker arm shafts, and valve guides.Drilled passages in the engine block also supply oil to the high-pressure fuel pump (3) and to oil lines that feed turbochargers (4). The return oil from the turbochargers drains into the oil pan through mounting supports (5) through the rear housing. Return oil from the high-pressure fuel pump drains back into the oil pan through the front housing.The main oil gallery is connected to the main bearings by drilled holes. Drilled holes in the crankshaft connect the main bearing oil supply to the rod