Continuously Variable

CTI Mag: Continuously Variable Transmission fit for a Global Market

Continuously Variable Transmission fit for a Global Market

The CVT represents the 2nd largest volume product in the global automatictransmission market. The rising popularity of crossover SUVs in many of the main markets requires comfortable, highly efficient and hybrid-ready transmission solutions. Punch Powertrain’s new torque converter CVT family is fit for that demand.

Dr.ir. Alex Serrarens, Manager Business Development, Punch Powertrain Nederland B.V.
Ir. Koen Laurijssen, Manager System Engineering – CVT Development, Punch Powertrain N.V.
Darren Foster (B.E.), Product Architect VT5, Punch Powertrain Nederland B.V.

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Issue: #December 2017

Context

Increasing vehicle efficiency and emission reduction has to be contributed for by all members of the modern powertrain. Ultra-high combustion efficiency, various levels of hybridization and a very efficient and functional transmission are mandatory to comply to worldwide emission regulations, particularly CO2. Such measures should not degrade or should even improve the comfort, convenience and performance of the vehicle to justify the higher cost that is usually  involved with clean(er) powertrains, particularly those with increasing levels of electrification. A counter-intuitive trend within the strive for efficiency is the high rise of the very popular cross-over and SUV segments. Particularly in regions where fleet-average fuel consumption and real world emissions come in place, such vehicles even put more pressure on the powertrain requirements. Finally, an additional trend impacting the future powertrains is Advanced Driver Assist Systems and ultimately Automated Driving. In the combination of things, the powertrain should be efficient, safe as well as silent and very smooth.

Given these high level requirements as well as our expertise and background in CVT development and production, Punch Powertrain has designed a totally new and future-ready CVT family of which the first product enters into production in China before the end of 2017. This new CVT—named VT5—realizes a higher efficiency, ratio coverage and comfort level than its predecessor (VT3) and many of its competitors. The first production application vehicle is a cross-over SUV with 250Nm 1.5L TGDI gasoline engine.

Growth of Automatic Transmission Market

Where 20 years ago, only 2 types of transmissions: MT and AT mainly dominated the automotive industry, today the automatic transmission experiences fierce competition from DCT and CVT, particularly in China. In the US, the traditional automatic is increasingly replaced by CVT. Collectively, DCT and CVT outpace the traditional automatic transmission by 2023. The youngest type disrupting the drivetrain but also the car market as a whole are battery-chargeable vehicles, that is EV and PHEV. Punch Powertrain is active in all growing segments, see Figure 1. The manual transmission more or less sustains its absolute production volume, however in an ever-increasing world market volume, it has to give away market share to CVT, DCT and battery vehicles.

The main reasons for AT losing ground in the world wide automatics market is that it is harder to meet the differentiating requirements in the various regions. For highest efficiency, and sporty step shifting usually a DCT is the best choice. When fuel efficiency resembling the MT is required in combination with easy (and fast) application as well as smooth, comfortable driving, CVT is the best choice. The traditional AT cannot meet up with this new mix of requirements, so more OEMs are choosing either or even both of these new risers within their portfolio.

Another aspect relating to the rise of CVT and DCT has to do with hybridization. It appears easier for offset type of transmission (like CVT and DCT) to integrate electric machines than for other transmission types. This urges OEMs to choice for portfolio transmission solutions where conventional, 48V and high voltage (HV) hybrids can be modularly produced with the same base transmission design. As an independent CVT supplier, Punch Powertrain develops such new modular CVT family in various torque classes where the new VT5 CVT (Figure 2) is the first in this future proof portfolio.

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