CUP 4B8393 - Caterpillar

Illustration 1 g01107127
Lubrication system schematic (1) Unit injector hydraulic pump (2) High pressure relief valve (3) Passage to the rocker arms (4) High pressure oil line (5) Injection actuation pressure control valve (6) High pressure oil passages (7) Oil supply line for Unit injector hydraulic pump (8) Piston cooling jets (9) Cylinder head gallery (10) Passage to pushrod lifters (11) Main bearings (12) Camshaft bearing (13) Passage to engine oil pan (14) Main oil gallery (15) Turbocharger oil supply line (16) Passage to front housing (17) Passage to oil pump idler gear bearing (18) Oil filter bypass valve (19) Passage to camshaft idler gear bearing (20) Passage (21) Engine oil filter (22) Oil cooler bypass valve (23) Engine oil cooler (24) Engine oil pump (25) Oil pump bypass valve (26) Engine oil panEngine oil pump (24) is mounted to the bottom of the cylinder block inside the engine oil pan (26). The engine oil pump (24) pulls oil from engine oil pan (26). The engine oil pump pushes the oil through the passage to the engine oil cooler (23). Oil then flows through engine oil filter (21). The filtered oil then enters the turbocharger oil supply line (15) and main oil gallery (14) .The main oil gallery (14) distributes oil to main bearings (11), piston cooling jets (8), and camshaft bearing (12). Oil from main oil gallery (14) exits the front of the block. The oil then enters a groove that is cast in the front housing.Oil enters the crankshaft through holes in the bearing surfaces (journals) for the main bearing (11). Passages connect the bearing surface (journal) for the main bearing (11) with the bearing surface (journal) for the connecting rod.The front housing passage sends the oil flow in two directions. At the upper end of the passage, oil is directed back into the block and up to cylinder head gallery (9) through a passage to the rocker arm (3). Passage (17) sends oil to the oil pump idler gear bearing.Oil from the front main bearing enters a passage (19) to the camshaft idler gear bearing. Oil passages in the crankshaft send oil from all the main bearings (11) through the connecting rods to the connecting rod bearings.The passages send oil from the camshaft bearing (12) to an oil passage in the side covers. The oil then enters a hole in the shafts to pushrod lifters (10). The oil lubricates the bearings of the lifter.The Unit injector hydraulic pump (1) is a gear-driven axial piston pump. The Unit injector hydraulic pump raises the engine oil pressure from the typical operating oil pressure to the actuation pressure that is required by the unit injectors. The injection actuation pressure control valve (5) electronically controls the output pressure of the Unit injector hydraulic pump (1) .The oil circuit consists of a low pressure circuit and a high pressure circuit. The low pressure circuit typically operates at a pressure of 240 kPa (35 psi) to 310 kPa (45 psi). The low