Engine Lubrication: Description and Operation

Oil Supply

The oil supply in the new generation of engines has been essentially redesigned with the following objectives in mind:
- To ensure the supply of oil even during very high lateral and axial acceleration
- To reduce friction and drive losses

The main differences between the new oil supply system and that used on previous models are as follows:
- Additional oil extraction point in the cylinder head
- Electronic demand-controlled oil pump
- Additional watertight sheetmetal panel between crankcase and oil pan







Compared with the previous models, the new 3.6 and 3.8-liter engines have not only one, but two extraction points in each cylinder head. In addition, the new 911 engines now have a total of 5 oil pumps instead of 3. These are located in the oil pan and are driven by a shared shaft. They include 4 extraction pumps for the cylinder heads (2 per cylinder head) and a new demand-controlled oil pressure pump.







Demand-controlled oil pump

In order to reduce drive losses from auxiliary units and improve the efficiency of the engine, while at the same time reducing fuel consumption, the new 911 Carrera models are fitted with an electronic demand-controlled oil pump.

With this new oil pump, the delivery pressure and volume is controlled for the entire engine map. In other words: the required oil pressure and a defined oil volume is set for each engine operating state (e.g. different engine speed and load). The oil pump is integrated neatly in the oil pan area and is driven directly by the crankshaft via a chain.

Function







Depending on the input values for engine speed, engine load, engine oil temperature and the expected change in engine speed, a specific control valve (4) position is defined using a map in the DME control unit. The control valve position regulates the oil pressure for the spring piston on the gear wheel, which can move in axial direction. The oil pressure on the control piston is not regulated on the other side. The control valve is open fully in the non-energized state and as a result, the oil pressure is the same on both sides, which means that the gear wheel will not move. In other words: the pressure difference between the spring piston and the control piston can be used to control every position. When the gear wheel moves, the teeth are still only partially engaged and as a result, power and friction as well as energy requirements are reduced.







To extract oil from the two cylinder heads, the four additional oil pumps are integrated in the main oil pump housing so that the oil in the cylinder head on the new 911 Carrera engines is extracted at two points.


Oil circuit