Dual Mass Flywheels Reduce NVH

The use of dual mass automotive flywheels is resulting in enhanced driving comfort and smoother running

The dual-mass flywheel (DMF) from Schaeffler is an integrated spring/damping system that promotes extra-smooth motor running, reduces engine noise and helps save fuel in internal combustion engine and hybrid vehicles.

Schaeffler first introduced this innovation for significantly enhanced acoustic and driving comfort onto the market some time ago but the technology has since gained increased relevance not just for improving ride comfort but reducing emissions in the age of hybrid powertrains.

According to Schaeffler CEO Automotive Technologies Matthias Zink, the dual-mass flywheel is a good example of how company’s like Schaeffler can make improvements to existing technology.

“What began a number of years ago as a clever idea for damping vibration in gasoline engines has remained to this day an effective method for improving vehicle ride comfort while also lowering fuel consumption and hence CO2 emissions,” he says.

Schaeffler manufactures the product for customers all around the world at its plants in Bühl (Germany), Szombathely (Hungary), and Taicang (China). The plant in Bühl – the dual-mass flywheel’s birthplace – has itself produced over 100 million units of the product since it first went into production.

Continuous technical refinement

The development of the dual-mass flywheel at Schaeffler’s Bühl campus was the end result of intensive detail work and the big market breakthrough came with the addition of the arc spring damper, which improved the flywheel’s performance as well as reducing the cost of the overall system.

While the primary flywheel mass was originally made of cast or forged steel, Schaeffler’s expertise in metal forming soon enabled it to make all components except for the secondary mass from formed sheet metal parts. This made the system lighter and paved the way for the DMF to go into widespread use.

By 2000, the company was producing around two million units annually, meaning that 20 per cent of all manual-transmission cars in Europe were benefiting from significantly reduced noise, vibration and harshness, as well as comfort thanks to the innovation.

After continued development work, the company introduced the centrifugal pendulum-type absorber, further improving the DMF’s vibration and noise damping performance. Today, Schaeffler makes this spring/damper system in several hundred variants for more than 50 customers worldwide.

Torsional vibration isolation

Installed between the engine and the transmission, the flywheel prevents torsional vibrations from the piston action of the engine from propagating along the drive train to the transmission. The secret to this is the pendulum mass of the flywheel’s centrifugal pendulum-type absorber, which exerts a force against the direction of rotation of the engine. This cancels out the torsional vibrations produced by the engine almost entirely, delivering major benefits, particularly when driving with lower engine speeds. The system is also a highly effective means of absorbing drive train noise.

It also reduces fuel consumption by facilitating driving in the more fuel-efficient lower engine speed range, which also lowers CO2 emissions.

• Author
• Recent Posts

Jonathan Newell

Jonathan Newell is a graduate of Loughborough University and has three decades of experience in engineering as well as broadcast and technical journalism.

Latest posts by Jonathan Newell (see all)

• UK manufacturing steps up to COVID-19 crisis - April 2, 2020
• Clustering Innovation - March 12, 2020
• A Global Monitor - March 6, 2020