Speaker Interview: Han-Hein Spit, Vice President at Bosch Transmission Technology BV
Han-Hein is responsible for marketing, sales and project management for the Bosch CVT pushbelt business.
He shares with us his optimism about the future of EV and hybrid powertrains, and explains how Bosch’s pushbelt CVT offers improved performance leading to better driving range and lower costs.
What do you see as the future for new mobility services, and how will next-generation hybrids and EVs fit into this model?
Electrification shows no sign of slowing. Bosch predicts that by 2020, 3% of all new powertrains will be EV and a further 6% hybrid. By 2030, the EV share could increase to a fifth of all new vehicles. In the meantime, hybrid vehicles are bridging the gap between ICEs and EVs. It is expected that the hybrid market will grow further in the coming years and will remain in the next decades. This may sound like bad news for those who work in the transmission industry, but this might not necessarily be the case.
For many in the transmission industry, electrification may actually bring opportunities. Single-speed drives have brought BEVs only so far. The next generation of electric vehicle drivers are going to want more from their cars. Bosch identifies a chance here for transmissions. Transmissions can enable EVs to operate more efficiently, providing more traction force or top speed when required, and the pushbelt continuously variable transmission (CVT) has been developed solely for that purpose.
The hybrid market can also benefit more from the use of transmissions in its powertrains. Transmissions and e-motors are now two completely different markets. If these come together, there will be great opportunity for synergy. Developers of e-motors should now start to consider the transmission and specifically CVT as a possibility, a solution. This is potentially the key to our future powertrains. As in the early days of the internal combustion engine, the majority of powertrain developers still have to discover the strength of pairing a continuously variable transmission system with an electric motor; but undoubtedly, the success of the CVT and ICE combination (having approximately 25% market share in the two-pedal passenger car market) could be extended to the electrified powertrain era, bringing a variety of new opportunities for the transmission industry.
What is the potential of CVT technology in improving electrified powertrains?
The CVT transmission system offers EVs improved performance, including increased continuous power and improved peak efficiency levels, which means better driving range and lower costs. The system makes it possible to have a vehicle in its optimum working condition. Either it can drive in the most energy-efficient gear or it can accelerate smoothly for optimum power.
There is a great opportunity for e-powertrains to use a smaller CVT that is activated electromechanically instead of the current hydraulically actuated systems, further improving the efficiency of the transmission. The combination of an electric engine and smaller CVT system is a better solution than a bigger, heavier battery or expensive high-performance e-motor. The additional expenses for a CVT are saved within the entire powertrain by lowering the electric motor cost including its cooling and batteries.
Bosch Transmission Technology, already in the hybrid vehicle transmission market with P2 and P3 configurations based on the CVT, is planning to enter the electric vehicle market by 2025 with a pushbelt CVT system that promises to increase range, reduce battery capacity and improve performance while retaining the EV feel with smooth powershift and silent drive. The CVT variator was designed with electric vehicle application in mind: it is quiet and responsive, comfortable, highly efficient, low in weight and compact in size. With a ratio coverage of approximately 4, the use of a pushbelt CVT creates higher efficiency as well as better performance. The added downsizing opportunities for electric motors help to extend the range, at lower costs for EV manufacturers.
The single loopset (push) belt (SLB) design promises to cut losses by up to 40% and reduce variator volume by 12%, thereby reducing transmission weight and cost by 10% and 3% respectively. A pushbelt CVT is able to retain the smooth, silent and shiftless behaviour of an e-motor; but with the same battery capacity and e-motor, you are able to create more traction force at the wheels when needed. By adding a CVT, the maximum torque requirements of electric motors can be reduced, enabling manufacturers to reduce the size and cost of the active parts. Such downsized e-machines combined with a CVT can deliver the same performance with lower losses than current high-revolution e-motors, which also offers opportunities to simplify the cooling systems and balancing requirements of the e-motors, and extend the driving range of the vehicle.
What are OEMs looking for from CVT technology today?
In the scramble to get into the market, the first generation of EVs has been lacking in several areas; concerns about range and recharge times, for instance, have meant that the EV industry mainly concentrated on cost and time-to-market. The idea and focus in electrical powertrains is to push these into the market with as few components as possible. Right now, everything is aimed at cost saving and making vehicles as light as possible. Electric vehicles need more diversified powertrains in order to appeal to a wider crowd. At the moment, EVs are not yet ready for widespread use. Most people can’t afford them, and if they can, current EVs are not capable of providing the full characteristics that the modern motorist is used to, such as easily driving up a steep hill or towing a trailer.
Undoubtedly, as Tesla Motors has shown, when it comes to EVs, acceleration performance matters to some consumers just as much as efficiency. But to provide the power requirements of the modern motorist creates a problem for a lot of EV manufacturers. More powerful EVs mean the expensive development of electric motors, and the battery capacity to power them – without increasing the overall charging time (something that is already a barrier to purchase). Increasing battery capacity is very expensive and often makes batteries very heavy. The industry is now developing e-motors with a far higher torque capacity and rpm range, but this is, again, an expensive development and requires materials that are not widely available.
Han-Hein will be speaking at Electric & Hybrid Vehicle Technology Conference Europe on Wednesday 08 May 2019 at 08:30am on Hybridization: Examining the Latest Technologies and Architectures to Deliver Electric Vehicle Efficiency and Meet Customer Demands.