Oil circuit - as-built configuration - GF18.00-P-0800OM
ENGINES 651.9
Schematic diagram
Oil circuit function
All moving components on the engine, which are lubricated and cooled by engine oil, are supplied with engine oil via the engine oil circuit.
The lubrication reduces the friction and mechanical wear. Impacts are also absorbed by the oil buffer in the bearings. The oil circuit of the engine is supplied with engine oil via the oil pump. The oil pump is designed as a controlled vane-type pump, is driven by the gear drive and has an integrated pressure limiting valve which limits the oil pressure to max. 10 bar. When the engine is started, the oil pump draws the engine oil out of the oil pan via the suction line with prefilter and delivers it to the oil-water heat exchanger via the pressure line with integrated return flow check valve.
During the cold-start phase, the oil-water heat exchanger ensures that the engine oil is warmed up rapidly. After the warm-up phase, the oil-water heat exchanger serves to cool the engine oil.
The coolant flow of the oil-water heat exchanger is controlled mechanically by a thermocouple depending on the engine oil temperature. After the engine oil has passed through the oil-water heat exchanger, it enters the oil filter module.
To ensure that the engine continues to be lubricated even if the flow of oil through the oil-water heat exchanger is obstructed (e.g. by dirt), a pressure differential valve is installed parallel to the oil-water heat exchanger whereby the oil can be bypassed at the oil-water heat exchanger. In the oil filter module, the engine oil flows in through the oil filter element, thereby cleaning the filter element. If the flow of oil in the oil filter element is obstructed, for example through excessive dirt, the oil filter bypass valve is installed parallel whereby the oil can be bypassed at the oil-water heat exchanger. The engine oil then passes into the main oil duct and transverse oil duct in the crankcase.
The main oil duct supplies the crankshaft bearings, connecting rod bearings, intermediate gear and balance shafts with engine oil directly, and the oil spray nozzles are supplied via the oil spray nozzle shutoff valve.
Engine oil is sprayed over the oil spray nozzles under the piston crowns thereby cooling them.
The two exhaust gas turbochargers are also supplied with engine oil via a bypass along the main oil duct.
The vacuum pump is mounted directly upstream of the oil pump and supplied with engine oil.
The oil supply for the cylinder head branches off from the main oil duct. The following lubrication points are supplied with engine oil in the cylinder head:
- Camshaft main bearing
- Hydraulic valve clearance compensation
- Cam on the respective camshaft
- Timing chain oil spray nozzle
The following lubrication points and components are supplied with engine oil via the main oil duct in the timing case:
- Chain tensioner
- Intermediate gear for gear drive
The engine oil passes back into the oil pan via the return ducts.
The oil level check switch (S43) is used for monitoring the engine oil level and the oil temperature sensor (B1) is used for monitoring the oil temperature.
As of 06/10 the engine oil pump valve regulates the engine oil quantity, according to requirements, which is fed to the engine oil pump. In this way the supply of the engine with engine oil in the oil circuit is optimizes and the power loss of the engine and the fuel consumption drop.
The oil spray nozzles are switched off in the post-start phase if one of the following conditions is met:
- Engine oil temperature > -10°C
- The max. shutoff time (depending on the model, engine power, intake air temperature and engine oil temperature) is not reached
- The engine speed or injection quantity has not reached the established limit value
At high engine oil temperatures, activation of the oil spray nozzles can be interrupted depending on the engine speed.