Oil pump

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The main functions of the oil circuit correspond to those of its predecessor. The oil has the following task:

Lubrication
Controlling the shift elements
Transmitting torque
Cooling

It is a conventional recirculated compressed-air system with an oil pump that supplies a pressure control valve and itself is supplied from an oil sump. The pressure control valve (system pressure valve) sets the system pressure. The system pressure is between 5.5 and 17.5 bar at a volumetric flow of 14.5 cm³ per minute.

A new type of oil pump is used. A double vane-type compressor is used in the 8-speed automatic gearbox.

Double means that the shape of the pump body enables two supplies in one rotation of the pump. The double vane-type compressor is located in the gearbox behind the converter housing, above oil level. It is driven by a slightly faster rotating rolling tooth-type chain directly from the converter neck.

The oil pump takes in through a filter and supplies the oil to the system pressure valve. The required system pressure is set.

Excess oil is returned to the intake port of the oil pump. Introduction into the intake port is in the direction of flow so that this has a charging effect. Cavitation and noise emission are therefore avoided and efficiency is improved.

The advantage of the double vane-type compressor is its small size compared to its delivery rate. The efficiency of the oil pump has improved by 10 - 30 % across the entire engine speed range compared to the toothed pump in the 6HP automatic transmission.