Volkswagen goes greener with new manual gearbox

The MQ281 gearbox will be fitted to the new Passat, which is due to launch in September. It will later be added to almost all of the vehicle classes within the Volkswagen Group.

Depending on the engine and vehicle combination, the gearbox can save up to five grams of carbon dioxide per kilometre, according to Helmut Göbbels, head of manual gearbox and 4-wheel-drivetrain development at Volkswagen.

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This includes “downspeeding”, or driving in high gears at low engine speed in order to save fuel.

“The gearbox must play its part in the continuous improvement of the overall vehicle´s fuel consumption,” Göbbels said.

To develop the new gearbox, Volkswagen’s engineers used computer modelling techniques, including simulating transmission fluid flow in order to ensure uniform and optimum lubrication of all necessary components under all operating conditions, Göbbels added.

“The delivery action as well as the turbulence generated by rotors such as gears were simulated with this method,” he said. “The simulation focused particularly on operating ranges with a low engine speed, which pose particularly demanding requirements regarding transmission fluid delivery.”

By improving the lubrication of all gear wheels and bearings, the company was able to reduce the amount of oil required by the gearbox over its lifetime to just 1.5 litres.

To reduce friction even further, a bearing concept adapted to the gearbox, using friction-minimised bearings with low-contact seals, was developed.

Using finite element analysis, the team also optimised the use of materials and their distribution within the gearbox housing, said Göbbels. This allowed them to achieve the maximum stiffness level for the structure, while minimising material use.

The team also used a virtual “acoustic fingerprint” development method to design the gearbox’s acoustics.

“This method was used to simulate the sound radiation behaviour at the transmission's connection points under consideration of an optimal gear engagement behaviour,” Göbbels explained.

The new housing improves driving comfort by reducing the level of noise and vibration.

The new gearbox is being manufactured in-house, with production being ramped up at Volkswagen’s plants in Barcelona in Spain and Córdoba in Argentina.

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