Oil circuit function

S18.00-2500-06

Front view of engine

1 Top chain tensioner

2 Lubrication point for intermediate shaft

3 Bottom chain tensioner

4 Oil-water heat exchanger

5 Bypass valve

6 Filter housing

7 Filter element

8 Oil pump

9 Oil pan

10 Pressure relief valve

11 Return flow check valve

S18.00-2501-06

Side view

12 Oil spray nozzle for cooling piston

The engine lubrication system reduces the mechanical wear and tear of the moving parts and facilitates their operation. In addition, these components are cooled and shocks absorb.

The principal components of the engine lubrication and cooling system are:

- Oil pump

- Oil filter

- Oil-water heat exchanger

- Pressure relief valve

- Return flow check valve

- Oil spray nozzles

Oil pump

The oil pump is designed as a gear pump which is driven through a shaft by the intermediate shaft of the engine. It pumps the lubricating oil required out of the oil pan and through the oil passages to the individual lubrication points of the engine.

Oil filter

The oil filter is attached to the crankcase in a re-usable housing.

The filter is provided with a filter element. This makes it possible to minimize the environmental impact during disposal by reducing the portion of residual oil.

-----------------------------------------------------------------------------------------

The oil filter housing is provided with one feed and two outlet passages; the second outlet passage is equipped with a bypass valve, which is normally closed.

If the oil filter is blocked, the rise in pressure in the oil filter housing causes the bypass valve to open. As a result, lubrication of the engine is assured, although the oil which now flows through the bypass valve, is unfiltered.

Oil-water heat exchanger

The oil-water heat exchanger is located on the side of the crankcase.

Both the engine oil as well as the coolant of the engine flow through the heat exchanger in separate passages. As the engine coolant has a slightly lower temperature than the engine oil, the coolant absorbs the heat of the engine oil and thus cools it.

Pressure relief valve

The pressure relief valve is located in the oil pump and regulates the oil pressure to a maximum of 5.5 bar.

If too much engine oil is supplied at high engine speeds, the pressure relief valve opens and allows the engine oil to flow back directly from the oil pump to the oil pan.

-----------------------------------------------------------------------------------------

Return flow check valve

The return flow valve is designed to prevent the engine oil flowing back into the oil passages or into the oil pan when the engine is not running. The oil passages are always filled with engine oil for this purpose. This prevents valve clatter when restarting the engine and ensures optimum lubrication of the components from the outset.

The valve is located between the cylinder head and crankcase.

Oil spray nozzles

The oil spray nozzles are located in the crankshaft bearing brackets. One oil spray nozzle is provided for each cylinder.

The piston crowns are cooled by means of the oil spray nozzles. The nozzles are designed as pressure valves and spray engine oil below the piston crowns from a pressure of 2 bar.

The oil for the oil spray nozzles is supplied through a drilling in the bearing bracket and a groove below the bearing shell.