C13 Tier 4 Final Engines Lubrication System Caterpillar

Illustration 1	g01897775
Lubrication system schematic (1) Piston cooling jets (2) Main oil gallery in cylinder block (3) Engine oil pressure sensor (4) Oil flow to valve mechanism (5) Camshaft journals (6) Main bearings (7) Signal line (8) Oil filter base (9) Oil line to turbocharger (10) Engine oil cooler (11) Oil cooler bypass valve (12) Engine oil filter bypass valve (13) Engine oil filter (14) Oil pan sump (15) High pressure relief valve (16) System oil pressure regulator (17) Engine oil pump

Illustration 2	g01897793
Right side view of engine (10) Engine oil cooler (13) Engine oil filter (17) Engine oil pump

The lubrication system supplies filtered oil at a maximum temperature of 110 °C (230 °F), a nominal pressure of 375 kPa (54 psi) and a minimum pressure of 241 kPa (35 psi) at rated engine operating conditions. The system oil pressure regulator (16), which is located in the filter base, protects the lube system and components from higher oil pressure in excess of 450 kPa (65 psi). The system oil pressure regulator (16) is controlled by the signal line (7). The signal line is connected to the main oil gallery, but not to the oil pump. The engine oil pressure in the main oil gallery is independent of the pressure drop that is caused by the engine oil filter and the engine oil cooler.

The opening pressure for the oil cooler bypass valve (11) and the oil filter bypass valve (10) is 204 kPa (30 psi) of pressure differential. . The oil filter bypass valve ((10 )) and oil cooler bypass valve ((11)) protect the engine components from oil starvation during cold starts.

The high pressure relief valve ((15)) opens at 695 kPa (101 psi) in order to protect the engine from unsafe excessive system oil pressure. When the high pressure relief valve is open the engine oil bypasses the oil system and returns to the sump until the pressure falls below 695 kPa (101 psi).

The engine oil pressure sensor (3) provides engine system pressure data to the Onboard Diagnostics (OBD) through the Electronic Control Module (ECM). The engine oil pressure sensor is also part of the engine protection system.

The journal bearings of the turbocharger are lubricated by the oil line to the turbocharger (9) directly from the oil filter base. The oil drain line from the turbocharger then returns the oil flow to the sump.

Oil Flow Through The Lubrication System

Illustration 3	g01911773
Oil filter base (18) Oil from engine oil cooler (15) High pressure relief valve (19) Oil to engine oil cooler (20) Oil sample tap (12) Engine oil filter bypass valve (21) Oil line to turbocharger (16) System oil pressure regulator (11) Oil cooler bypass valve (22) Oil from engine oil pump

The engine oil pump is mounted to the back of the front gear train on the lower right hand side of the engine. The engine oil pump is driven by a gear that is directly connected to the crankshaft gear. During normal operation, the pump supplies oil from the sump through the engine oil cooler and the oil filter to the main oil gallery. The pump and system pressure is controlled by the System oil pressure regulator (16). The engine oil pump can supply excess oil for the lubricating system. When this situation is present, the oil pressure increases and the oil pressure regulating valve opens. The open oil pressure regulating valve allows the excess oil to return to the sump.

The engine oil cooler uses engine coolant to cool the oil. Oil cooler bypass valve (11) will open when the oil pressure drop across the oil cooler exceeds 204 kPa (30 psi). Opening of the bypass valve will force the oil around the engine oil cooler into the oil filter. If the pressure drop across the cooler falls below 132 kPa (19 psi), the bypass valve will close and the oil flow continues through the oil cooler.

During normal operation, approximately five percent of the oil flow is directed through an orificed passage that leads to the secondary oil filter (if equipped). The oil flows through the bypass filter and returns back to the engine oil sump. The main oil flow now flows toward the primary engine oil filter. When the oil pressure differential across oil filter bypass valve (12) reaches 204 kPa (30 psi), the valve allows the oil flow to bypass the primary engine oil filter in order to lubricate the engine parts. The bypass valve provides immediate lubrication to the engine components when there is a restriction in the primary engine oil filter due to the following conditions:

• Cold oil with high viscosity

• Plugged primary engine oil filter

Note: Refer to Specifications, "Engine Oil Filter Base" for a cross section of the valves in the engine oil filter base.

Illustration 4	g01946593
Interior of cylinder block (1) Piston cooling jets (23) Piston (24) Connecting rod

Filtered oil flows through the main oil gallery in the cylinder block (2) to the following components:

• Piston cooling jets

• Valve mechanism

• Camshaft bearings

• Crankshaft main bearings

• Turbocharger

• Nox Reduction System (NRS) valve

The piston cooling jets provide the underside of the piston with liberal amounts of oil. The oil is used to remove heat from the piston as well as lubricating the piston rings.

The breather allows engine blowby to escape from the crankcase. The engine blowby is directed to the Open Crankcase Ventilation (OCV) filter in order to remove oil particles before being discharged into the atmosphere through a hose. This prevents pressure from building up that could cause seals or gaskets to leak.