The success of DCTs has shown that there is an appetite for new automatic transmission technologies that combine smoothness with emissions-cutting efficiency. The challenge continues to be cost. just-auto spoke to Bill Martin, managing director of Zeroshift, who believes his company could be part of the solution.
just-auto: We profiled Zeroshift a few years ago. What developments have there been since then? What challenges are you currently addressing?
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Bill Martin: The last three years have been interesting for everybody in the industry. As a developer of alternative transmission concepts, Zeroshift has seen the pressure on CO2 emissions and finances increase at the same time. This has changed the way in which our customers see Zeroshift fitting with their strategies.
We’re working with several vehicle manufacturers and engineering consultancies on main drive transmissions that help engines work more efficiently. There is also a strengthening focus on our technology’s suitability for hybrid and electric drivetrains, where it can help to make more of the battery capacity and so help to work around the limitations of today’s battery technology.
There seems to have been a change in attitudes generally. I get the impression that the industry is more willing to listen to different ideas; that strategies are more aligned. There is growing interest in using automated manual transmissions (AMTs) in hybrid vehicles that have electric rear axles, for example. A less expensive automatic main transmission at the front helps to offset the additional costs you’re adding in at the rear.
Some manufacturers are also looking at fitting electric motors to the AMT for hybrid functions, which interests us as well. Zeroshift’s technology provides all the cost and packaging benefits of an AMT with the added benefit of smooth gear changes with no torque interruption.
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By GlobalDataI think the challenge facing all companies at the moment is to make the right choices when it comes to R&D dollars. Zeroshift has the advantage that it helps to reduce CO2 cost-effectively, no matter whether the programme involves conventional, hybrid or electric powertrains.
just-auto: Have you seen investment move from alternative powertrains to transmissions?
Bill Martin: We see that more and more manufacturers are analyzing the energy’s path to the wheels and removing as much drag as possible in the drivetrain. Transmission development can get significant fuel efficiency gains cost-effectively and quickly. Manufacturers are reviewing each sub-system to achieve peak efficiency and reduce power losses. The recent introduction of wet launch clutches to replace the torque converter on some planetary automatics is a good example of this.
Controlling multiple clutches, hydraulic actuation systems and synchromesh actuation all consume power. The industry sees that dry clutches are more efficient than wet clutches and that single-clutch systems are more efficient than dual or multi-clutch systems – hence the growing interest in AMTs and in Zeroshift’s technology.
just-auto: What is Zeroshift’s technology? How does it work?
Bill Martin: Our technology is an evolution of the AMT, a simple cost-effective means of retaining the mechanical efficiency of a manual transmission while providing the added functionality of an automatic. Zeroshift does this by replacing the traditional synchromesh pack with two drive rings. It works like a traditional dog-engagement gearbox, but instead of one ring, there are two, each driving the torque in one direction only. Small, lightweight forks then shift gear via low-power actuation.
Any Formula One transmission engineer will tell you that the most mechanically efficient gearbox is a lightweight single dry-clutch dog-engagement. Zeroshift gives you that, but in a way that drives as smooth as a traditional planetary automatic.
just-auto: How does your technology compare to dual clutch transmissions?
Bill Martin: For manufacturers, Zeroshift is more efficient, lighter, smaller and less expensive to develop, calibrate and produce. There are no hydraulics and no need for complex heat management for the two clutches. There’s also no need for wet and dry-clutch versions for different engines in the same vehicle since Zeroshift’s technology is not torque-limited.
For drivers, Zeroshift provides better acceleration and top speeds, and uses less fuel than a manual. The shifts are instant so the car feels sporty yet smooth.
just-auto: How does the move towards electric drivetrains affect Zeroshift’s proposition?
Bill Martin: A transmission that provides seamless shifts and improves efficiency is very important for EVs. People forget that electric motors aren’t perfect; they’re only about 95% efficient at best and at high and low speeds are only about 65% efficient. That can add up to quite a shortfall in range.
Having a number of gear ratios and the ability to shift without interrupting torque can extend the range by up to 10 percent. It also helps to reduce the compromise between high-speed cruising and fully laden launches that is inevitable in a single-speed set-up. Multi-speed gearboxes make sense for EVs and, compared to the cost of batteries, a transmission offers a much better return on investment.
Zeroshift has a multi-speed transmission concept under development especially for electric vehicles. With dampers on the gear hubs and electronic control of the motor, you will be able to make seamless ratio changes without adding a clutch.
That’s important because what people love about EVs is the way that their torque flows so smoothly and the immediacy of the launches. Zeroshift’s EV transmissions let you retain these characteristics; other attempts use at least one clutch, which also adds weight and power losses.
just-auto: How does the technology work with hybrids?
Bill Martin: Hybrids still need gearboxes and, like any car, they have to be more efficient than current technologies. From speaking to vehicle manufacturers, we know that many want to be able to package eight-speed transmissions in front-wheel drive platforms and be able to add some hybrid functions. Zeroshift is developing a system that does just this.
By removing the synchromesh you solve a lot of the weight, cost and packaging issues that such transmissions would normally face. Our system also uses the electric motors on the transmission to provide the start-stop function, so you can also remove the starter-generator. Our calculations suggest that it should be possible to develop an eight-speed automatic with start-stop for around the same cost as a six-speed manual transmission.
just-auto: How much interest is there in your technology among manufacturers?
Bill Martin: We can’t name clients of course, but Zeroshift is working with several vehicle manufacturers and engineering consultancies on projects. We have customer projects for applications that include motorcycles, hybrid passenger cars, hybrid medium duty trucks, motorsport and EVs.
For the superbikes, the emphasis is on providing uninterrupted acceleration with automatic gear changes that keep the rider’s attention focused on the road. Elsewhere the main benefit is of our seamless-shift gearbox technology is the reduction in fuel consumption and CO2 emissions. And it’s a relatively inexpensive means of doing that.
just-auto: How much does the technology cost to manufacture or license?
Bill Martin: Zeroshift licenses its technology and we usually only disclose the costs directly to customers. The car industry is very cost-conscious and we want to see the technology in production: we’ve made sure that the licensing arrangements are realistic and reflect this.
But to put it in context, it’s important to remember that what we’re proposing is much simpler than a lot of the drivetrain options manufacturers have been exploring. Zeroshift replaces the synchromesh pack with a couple of drive rings to give you an uninterrupted supply of torque. It compares well against other means of reducing CO2. We know that on many vehicles, compared to Zeroshift, fitting low-rolling resistance tyres is the only thing that cuts more grams of CO2 per euro invested.
