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New MANN-FILTER transmission oil filter for the e-axle

Contrary to some opinions, the majority of electric vehicles have a transmission that is housed in what is known as the e-axle. This e-axle is a compact solution for the electric drive of battery electric vehicles and applications in hybrid vehicles. Electric motor, power electronics and transmission are combined into one compact unit, which directly drives the vehicle axle.

To meet new electromobility requirements when it comes to oil filtration, the worldwide filtration expert MANN+HUMMEL developed new transmission oil filters to provide flawless cooling and lubrication of the e-axle. For commercial vehicles in the independent aftermarket, one of these transmission oil filters is available as MANN-FILTER W 7071 for Mercedes-Benz eActros 300 and eActros 400.

Lubrication and cooling with one oil
As all of the transmission components are integrated in the e-axle, one oil circuit in total is sufficient for both cooling and lubrication. Yet this is an advantage with a catch: Since the oil comes into contact with mechanical and electronic components, metal particles and chippings from the transmission can end up in the power electronics and the e-motor, causing them damage. Therefore, the e-axle only functions if these particles are removed from the system efficiently, quickly, and permanently. As with many conventional transmissions, the focus is on particle separation: A filter is required for this. 

The MANN-FILTER transmission oil filter W 7071 is fitted with the new MULTIGRADE O-eM 50 filtration medium, which is specially tailored to the oil requirements for lubricating and cooling e-axles. Specifically, the fully synthetic filtration medium works as follows: Pressure losses are reduced by approximately 50 percent and are therefore significantly lower compared to conventional transmission oil filters made of cellulose media. Another positive effect: Significantly reduced differential pressures cause the bypass valve to open for shorter times and less frequently. This allows more filtered, clean fluid to reach the areas requiring lubrication, ensuring a longer service life of the transmission. Low differential pressure also means lower energy requirements for the entire system and has a beneficial effect on the driving range of electric vehicles.

The fully synthetic filtration medium is also characterized by a significantly higher chemical resistance to becoming brittle during the period of use, which is why the filter is suitable for very long service intervals according to the vehicle manufacturer's specifications. In addition, the W 7071 has a high degree of separation: 99.5% with a particle size of 50 µm. For comparison: A human hair has a diameter of 50–100 µm.