Follow-up Report, 9th International CTI Symposium USA – Automotive Transmissions, HEV and EV Drives, 20-21 May 2015, Novi, Michigan
Efficient Drives: A Reality Check
Crude oil became significantly cheaper in 2015, not least because the USA is now an oil exporter again, and there is a global surplus. How long this cosy situation will last remains to be seen, but as the 9th CTI Symposium in Novi, Michigan (May 20-21) again showed, it has an impact on the debate over tomorrow’s drives. Even more than last year participants discussed, which and how much fuel-saving technology is needed to effectively reach fleet consumption targets like CAFE.
Chairman Ernie J. DeVincent, Vice President Product Development, Getrag, welcomed this year’s participants in a new setting: the Suburban Collection Showplace in Novi, Michigan. The event centre and attached hotel have more space for the symposium, which grew once again this year: some 520 participants attended, around 30 percent more than last year. Besides the eight plenary lectures, attendees could choose from 63 technical presentations and meet 40 exhibitors. With the exception of the ‘crunch year’ 2009 the North American CTI Symposium has grown steadily since 2007, and is now a central discussion platform for American and international transmission and powertrain developers.
How Can Transmissions Reduce Fuel Consumption?
In the opening lecture of the symposium on Day One, Getrag COO John McDonald made it clear there is no reason to relax just because oil prices have dropped. According to BP figures, oil reserves will not last much longer than 50 years based on today’s global population figures; in reality, strong global population growth and further variables could reduce that period further still. But as McDonald pointed out, transmission developers have more on their plates than calls for lower fleet consumption due to volatile resources. They also need to offer affordable solutions in a globalized market with differing customer requirement sets. McDonald says the ’Getrag Approach’ to this problem involves transmission technology that combines scalability and flexibility with a high degree of modularity and commonality. Thanks to on-demand actuation and clutch cooling – plus the inherently superior efficiency of layshaft transmissions – he says third-generation Getrag DCTs are now the most efficient form of automation, roughly 5 to 6 percent cheaper than a current 9-ratio automatic torque converter transmission. The speaker also noted that third-generation DCTs are scalable right up to a plug-in hybrid with high levels of modularity and commonality. As a result, McDonald concluded, Getrag can already offer transmission solutions that are future-proof, efficient and tailor-made.
The Right Transmission for the Right Vehicle
Mike Harpster, Director Propulsion Systems Research Lab, General Motors, provided an OEM’s take on powertrain requirements up to 2020 and beyond. The real challenge, he said, lay in meeting CAFE 2025 requirements without compromising on driveability. He believes in the ’right transmission for the right vehicle, which means fundamentally different solutions can each make sense. In certain circumstances, for example, a CVT could be more fuel-efficient than a fixed-ratio transmission despite its lower inner efficiency. For the automatic torque converter transmissions that remain popular in North America, GM is opting for 9 to 10 ratios – plus a cooperation with Ford to ensure the transmissions are not just efficient and comfortable, but affordable too. GM is taking a different route again with the second-generation Chevrolet Volt, which has a redesigned Range Extender drive with two electric drive modes and three Range Extender modes. The transmission is a planetary unit that manages the power of the internal combustion engine and two electric motors. On the other hand, given the advanced state of hybrid technology, Mike Harpster’s statement that ”conventional drives will come closer to hybrids in terms of fuel consumption” was surprising. He says the role of transmissions as ’transformers’ will diminish, and that they should always be seen as part of the overall system – particularly in view of the fast-growing importance of auto electronics, right up to car-to-x communication and automated driving.
Efficient Technology Has To Pay
As an environmental agency representative, Don Hillebrand, Director Argonne Center for Transportation Research, faces a real dilemma: how to bring fleet consumption figures down to 54.5 mpg in 2025 without overburdening the industry and auto drivers. One option would be to raise vehicle tax like ’they do everywhere else in the world’, which he says is hardly feasible in the USA: when the Clinton administration tried, it lost control of Congress to the Republicans for the first time in 40 years. Raising taxes, Hillebrand points out, is tantamount to political suicide. As a result, the USA approach involves making fleet consumption figures for CAFE (Corporate Average Fuel Economy) stricter for manufacturers every year until they hit 54.5 mpg in 2025, but also rewarding sensible technology that can cut fuel consumption. Hillebrand said the technologies already exist, but the issue was their price point. Even the most energy-efficient technology is no use if hardly anyone buys it. Summing up, he said the USA approach comprised ever-stricter fleet consumption figures, plus intensive research into the most efficient fuel reduction technologies as a way of cutting costs.
Efficiency by Low Friction
Philip A. George, Director Advanced Development, Schaeffler, began his lecture by summing up the dilemma all auto developers currently face. Emissions regulations are getting stricter, fuel is cheap … and on top of that, drivers expect comfort, not frugal, fun-free transportation. He said there was a huge set of technologies available, but that simply adding them up did not work. In his example, he showed how in reality, 1+1+1 is often less than 3, or even less than 2. In George’s view, the solution involves a systemic approach and two core challenges: further improving mechanical components, and affordable low voltage electrification that builds on those improvements. Accordingly, one core challenge involves reducing or eliminating friction. He said on a reference car with a footprint of 4.2 m2 (a mid-sized car according to CAFE rules), these mechanical improvements alone cut fuel consumption from 24 to 29 mpg. As an example of efficient hybridization, George presented the TDA (Transmission Driven Accessories) concept. This has an engine boost feature, plus the ability to avoid engine drag loss by separating secondary drive units from the powertrain.
2500 Years of Planetary Transmissions
Charles Gray, Director Transmissions and Driveline Engineering, Ford, gave interesting insights into the history of planetary gearsets. He noted that the ancient Greeks had the idea around 500 years B.C., but that it was not until 1908 that Ford fitted a two-ratio transmission in the Model T. Since then, he said, the technology has evolved continuously. From the Ford perspective, the latest high points are the patent application for an 11-ratio automatic transmission in 2015, and the introduction in 2017 of the 10-ratio automatic shift developed together with GM. Gray sees considerable room for improvement in production methods, now and in the future. These include gear tooth modifications to improve durability and NVH, hard finishing for NVH-critical gears only and further improvements to manufacturing methods, but also advanced torsional vibration absorbers and lower drag loss in clutches. Charles Gray also cited Moore’s Law, which states that the number of transistors on an integrated circuit doubles every two years. As a result, 10 or 11 ratios can now be handled – a number that used to be unthinkable. The lecture title was ’Can we make it?’. Gray’s answer: ”Look how far we have come … can we make it? Yes, together”.
CVTs – a Partner for Dynamic and Autonomous Driving
Hiroyuki Kai, President Jatco Mexico, began by referring to the global trend that predicts over-proportional growth for CVTs and DCTs in the market for ’2-pedal’ transmissions’ up until 2020. He believes 85 percent of all automobiles will still have a combustion engine in 2030 (increasingly as part of a hybrid drive), and around 50 percent even in 2050. Jatco’s response is a straightforward CVT that can be hybridized with little effort, and has a commonality factor of over 70 percent. Mr. Kai also emphasized the functional flexibility of CVTs. On one hand, he said, the CVT ideally complements automatic and autonomous driving, because stepless operation made it particularly easy to keep the engine within its optimal efficiency zone. On the other, he said, Jatco also satisfies customers who like fixed-ratio transmissions with the ’D-Step’ feature that is now available on several series production Nissan models. Like Charles Gray before him, Kai showed how much untapped potential still lies in optimizing manufacturing processes. Improvements included continuously synching production and customer wishes (Douki), leaner manufacturing concepts, and enhanced manufacturing methods such as micro shot peening for the pulley surface so that CVTs can master even higher torque.
Turbine Powered Range Extender
Ian Wright began his career as a radio engineer in New Zealand, co-founded Tesla Motors, and is now the CEO of Wrightspeed Inc. His fascinating and unusual topic: a Range Extender drive for trucks that uses a gas turbine to generate electricity. Further downstream are two electric motors with two gear ratios each, to permit the use of high-speed electric motors, and a 200 kW inverter in between that Ian Wright calls a CVT. Why the analogy? Because like a CVT, the inverter enables power to be used steplessly – only with no clutches, converters, synchronizations or differentials. Wright says the stepless regulation is achieved simply by regulating the motor frequency. So why a turbine, not a combustion engine? Wright explained it’s because gas turbines deliver good efficiency only under maximum load, which is always given in a range extender configuration, but also because they are much smaller than engines, very reliable, need little maintenance and require almost no afterburn treatment (unlike diesels). He pointed out that the electricity generated was actually cleaner than the power mix delivered by power stations in the USA. Compared to a diesel truck, he said, the savings and benefits were impressive: -93% particulate matter, -82% NOX, -69% HC, -69% CO2 – and a lot less noise.
The Future of Autonomous Driving
’Roadmap to Autonomous Driving’, the lecture by Ali Maleki, Vice President Business Development, Ricardo North America, stayed a little closer to familiar concepts, yet was still deliberately provocative. His statements: ”By 2050, all automobiles will drive autonomously” and ”the majority of automobiles will be part of a sharing concept”. Maleki began by explaining how the different stages of autonomous driving are classified today. Under SAE J3016 there are: 0 = no automation, 1 = driver assistance, 2 = partial automation, 3 = conditional automation, 4 = high automation and 5 = full automation. Maleki believes 95 percent of all driving tasks can be mastered using ’conventional’ algorithms; the remaining five percent would need heuristic algorithms, i.e., the ability to conjecture and make decisions based on available information. This, together with concerns over data security, are currently the two most critical points in the public’s opinion of autonomous driving. Maleki reminded listeners that uncertainties of this sort existed at the dawn of the automobile age too: ”We have been there before and we will resolve this”. He said the necessary sensors are already there, and that the bigger challenge involved defining functional modules in a way that avoids excess complexity. Maleki expects integrated control modules to be created in software, grouped in an application framework, and based on the operating system and an ASIL layer (Automotive Safety Integrity Level) that interacts closely with the hardware. But the biggest challenge of all, he warned, lay elsewhere: What will the industry do if US auto sales drop by 40 percent over the next 25 years?
Driving Must be Fun
One way might be upholding fun-to-drive: Ian Wright for example, had given a second reason why he is backing gas turbine range extenders: ”Call it green, call it clean – we just call it cool“. In his lecture, Charles Gray had also explained how important motorsport still is for Ford. John McDonald had spoken of ‘four transmissions’ in one, by which he meant that software could not only make DCTs more fuel efficient, but comfortable, sporty or even supersporty too. The fact that CVTs from OEMs like Nissan or Subaru now ship with shift programs just because of the fun factor speaks for itself. One insight often heard at Novi was that ultimately, it’s automobile drivers who decide what they want – and driving enjoyment is definitely part of the mix.
Once again, the CTI Symposium USA had more participants and topics than the year before. The event showed that transmissions face an increasingly diverse range of tasks at the interface between efficiency and driving enjoyment. Another trend at Novi was that for developers, it now goes without saying that hybridization is one of many measures needed for compliance with CAFE. Each individual measure needs to be seen as part of the overall system, and the end result has to be affordable for drivers. Philip George from Schaeffler surely expressed the sentiments of many participants when he said: ”At the end of the day, it’s the volume that goes into CAFE“.
Author: Gernot Goppelt