3100 HEUI Diesel Truck Engine Lubrication System

Lubrication System Schematic
(1) Hydraulic pump. (2) High pressure relief valve. (3) Passage (to rocker arms). (4) Jumper tube. (5) High pressure oil line. (6) Injection actuation pressure control valve. (7) High pressure oil manifold. (8) Hydraulic pump oil supply line. (9) Piston cooling jets. (10) Cylinder head gallery. (11) Passage (to push rod lifters mounted in the side covers). (12) Main bearings. (13) Camshaft bearing. (14) Passage (to the oil pan). (15) Main oil gallery. (16) Turbocharger oil supply line. (17) Passage (to front housing). (18) Passage (to oil pump idler gear bearing). (19) Oil filter bypass valve. (20) Passage (to camshaft idler gear bearing). (21) Passage. (22) Oil filter. (23) Oil cooler bypass valve. (24) Oil cooler. (25) Oil pump. (26) Oil pump bypass valve. (27) Oil pan.

Oil pump (25) is mounted to the bottom of the cylinder block inside the oil pan (28). The oil pump (25) pulls oil from oil pan (28) and pushes the oil through passage to oil cooler (24). Oil then flows through oil filter (22). The filtered oil then enters the turbocharger oil supply line (16) and main oil gallery (15).

Engine Right Side
(16) Turbocharger oil supply line. (19) Oil filter bypass valve. (22) Oil filter. (23) Oil cooler bypass valve. (24) Oil cooler. (29) Turbocharger oil return line.

Engine Left Side
(1) Hydraulic pump. (7) High pressure oil manifold. (5) High pressure oil supply line. (8) Hydraulic pump oil supply line.

The main oil gallery (15) distributes oil to main bearings (12), piston cooling jets (9) and camshaft bearing (13). Oil from main oil gallery (15) also exits the front of the block and enters a groove cast in the front housing.

Oil enters the crankshaft through holes in the bearing surfaces (journals) for the main bearing (12). Passages connect the bearing surface (journal) for the main bearing (12) 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 (10) thru passage (3) to the rocker arm mechanism. A passage (18) sends oil to the oil pump idler gear bearing.

Oil from the front main bearing enters a passage (20) to the camshaft idler gear bearing (20). Oil passages in the crankshaft send oil from all the main bearing (12) thru the connecting rods to the connecting rod bearings.

The passages send oil from the camshaft bearing (13) to an oil passage in the side covers. The oil then enters a hole in the shafts to push rod lifters (11) to lubricate the lifter roller bearings.

NOTE: Engines equipped with an auxiliary oil filter (27) will pick up oil at a port and the filtered oil will be returned to oil pan (28).

The hydraulic pump (1) is a gear-driven axial piston pump. It raises the engine oil pressure level from typical engine operating oil pressure to the actuation pressure level required by the unit injectors. The injection actuation pressure control valve (6) electronically controls the output pressure of the hydraulic pump (1).

The oil circuit consists of a low pressure section and a high pressure section. The low pressure circuit typically operates at a pressure of 240 to 480 kPa (35 to 70 psi). Its function is to provide filtered engine oil to the hydraulic pump (1) as well as the lubricating system of the engine. Oil is drawn from the engine oil pan (28) and supplied through the oil cooler (24) and oil filter (22) to both the engine and the hydraulic pump (1).

The high pressure oil circuit provides actuation oil to the unit injector and operates in a pressure range typically between 4 and 23 MPa (581 and 3338 psi). This high pressure oil flows through lines into a high pressure oil manifold (7) located on the left side of the air inlet manifold. The manifold stores the oil at actuation pressure ready for unit injector operation. Oil is discharged from the unit injector under the valve cover so that no return lines are required.

After the lubrication oil has done its work, it goes back to the engine oil pan.

The oil pump bypass valve (26) limits the pressure of the oil coming from the oil pump (25). The oil pump (25) can put more oil into the system than is needed. When there is more oil than needed, the oil pressure increases and the oil pump bypass valve (26) will open. This allows the oil that is not needed to go back to the suction side of the oil pump (25).

With the engine cold (starting conditions), bypass valves (19 and 23) will open and give immediate lubrication to all components when cold oil with high viscosity causes a restriction to the oil flow through oil cooler (24) and oil filter (22). The oil pump (25) sends the cold oil through the bypass valves around the oil cooler (24) and oil filter (22) to the turbocharger oil supply line (16) and the main oil gallery (15) in the cylinder block.

When the oil gets warm, the pressure difference in the bypass valves decreases and the bypass valves close. Now there is a normal flow of oil through the oil cooler and oil filter.

The bypass valves will also open when there is a restriction in the oil cooler (24) or oil filter (22). This action does not let oil cooler (24) or oil filter (22) with a restriction prevent lubrication of the engine.

NOTE: See the topic, Oil Filter Group in the Specifications, for a cross section of the oil filter group valves.

Filtered oil flows through the main oil gallery (15) in the cylinder block. From here the piston cooling jets (9), valve mechanism, camshaft bearing (13), crankshaft main bearings, and the turbocharger cartridge are lubricated.

An oil cooling chamber is formed by the lip forged at the top of the skirt of the piston and the cavity behind the ring grooves in the crown. Cooling jet oil flow enters the cooling chamber through a drilled passage in the skirt and returns to the oil pan (28) through the clearance gap between the crown and skirt. Four holes drilled from the piston oil ring groove to the interior of the piston drain excess oil from the oil ring.

Engine Front Left Side
(29) Breather. (30) Hose. (31) Cylinder head.

Breather (29) allows blowby gases from the cylinders during engine operation to escape from the crankcase. The blowby gases flow or discharge through hose (30) into the atmosphere. This prevents pressure from building up that could cause seals or gaskets to leak.

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