Engine Lubrication: Description and Operation

Lubricating Oil System







To guarantee a reliable oil supply in all driving situations, the V8 engines in the Cayenne S and Cayenne Turbo have an integrated dry-sump lubrication system. The oil pan is designed in two parts and has an upper and lower part. The oil-water heat exchanger and the oil filter are fitted directly on the upper part of the oil pan.

To ensure a lightweight design, the oil plane, the oil return collection tank and the suction pipe are all together in a plastic housing fitted in the oil pan.







Likewise, the oil pan wall is very thin so as to keep the weight as low as possible.







Oil pump

The integration of VarioCam Plus, the mechanical vacuum pump and the fact that the lower part of the crankcase is fully aluminium means that oil throughput on the Cayenne S and Cayenne Turbo is very high. A relatively large and efficient pump must be used to guarantee the required oil supply. However, a lot of energy is required to drive such a pump and this energy requirement in turn increases fuel consumption. To counteract this, a variable oil pump is used for the first time in the Cayenne S and Cayenne Turbo.







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 position ( -4- ) 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-energised 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, performance and friction as well as energy requirements are reduced.







The Cayenne Turbo has an additional pressure oil line for turbocharger lubrication. A turbocharger suction pump ( -4- ) is integrated in the main oil pump for suctioning off the lubricating oil.

Control valve







The control valve is fitted on the oil pump in such a way that it can be accessed from the outside.

Oil spray jets

The temperature of the pistons in the Cayenne S and Cayenne Turbo engine is reduced by means of spray cooling. The spray jets are fitted on the upper part of the crankcase. The spray oil is also used for improved lubrication of the cylinder lining. To ensure the necessary engine oil pressure at low revs and high engine oil temperatures, the spray jets have an opening pressure of approx. -> pressure: 1.8 bar.