The Endangered Clutch Pedal
By Bill Visnic Ward's AutoWorld, Apr 1, 2008 12:00 PM

Not even a decade ago, the world's light-vehicle transmission sector was placid and staying true to its tradition for careful investment and incremental developments.

Probably the most unique — or riskiest, if you prefer — production effort was the continuously variable transmission, which was enjoying increased use by chief proponent Nissan Motor Co. Ltd. after a history of fitful development dating back to the 1980s.

The transmission world got turned upside down sometime around 2001, the year BMW AG and ZF Friedrichshafen AG introduced a 6-speed planetary automatic that delivered serious efficiency and drivability enhancements, compared with the 5-speed units that were settling in as the assumed pinnacle of automatic-transmission development.

This century's second Big Bang of transmission development came just a year later, when BorgWarner Automotive, in conjunction with Volkswagen AG, launched the remarkable Direct Shift Gearbox, a dual-clutch, automated manual transmission (DCT) employing BorgWarner's revolutionary Dualtronic components.

Suddenly, the formerly sleepy transmission sector is the focal point of industry buzz — first because these innovative new transmissions promise demonstrable efficiency gains for engineers charged with meeting fuel-economy standards green-lighted by Congress last fall.

And second, the functionality of these exciting new transmissions is blurring the lines between automatic and manual — to the point where the traditional manual transmission and the sometimes annoying clutch pedal may be headed for a hastier extinction.

That's the thinking of Bernd Matthes, president and general manager, BorgWarner Transmission Systems, who's happily presiding over the skyrocketing uptake of his company's DualTronic technology, which enabled the DCT for production vehicles.

Matthes isn't predicting the overnight extinction of the manual transmission, but he definitely sees the manual as a fading design, perhaps something on the order of the carburetor, which was outmoded by better technology required to improve fuel efficiency and emissions.

Matthes says some kind of automatic is likely to be a de facto requirement in the future, calling automatics “the tool to influence the fuel-efficiency and emissions equation.” He says manual transmissions are operated too erratically to ensure the fine degree of control required to produce optimum fuel economy and emissions.

And although emerging markets have caused a temporary uptick in global manual-transmission production, Matthes predicts some type of automatic quickly will come to dominate in those regions.

He says driver inexperience — many markets such as China and India have operators coming into 4-wheeled conveyance directly from bicycles or walking — and congestion in affluent areas that typically are the first to become heavily motorized, indicate these regions likely will migrate quickly to automatics, particularly once cost differences between automatic and manual are marginalized.

Paul Lacey, manager of North America technical research for Global Insight, also says new automatic-transmission options gradually will displace manuals, terminating the contract with your left foot. He cites General Motors Corp., for example, as an auto maker that appears to be heading down that road: Lacey says GM is “phasing out manual transmissions for trucks and medium-duties,” a large portion of its current portfolio.

And Lacey and several other sources say multi-speed automatics, DCTs — and let's throw in a dash of CVT — directly will chop into most auto makers' manual-transmission installation rates. That's particularly true for U.S. domestics, which are rapidly moving from a ground-zero position in terms of multi-speed automatics to one of fast adoption of 6-speeds or more, as well as DCTs.

In North America, manuals are losing ground annually. In 2007, 96.5% of domestic light trucks and 90.3% of domestic cars came equipped with automatic transmissions, an increase from 1997, when 88.7% of domestic passenger cars and 83.8% of light trucks were so equipped, according to Ward's data.

Penetration rates also are down for manuals in import vehicles, although they remain higher than for the domestics, Ward's data shows.

Why? Conventional planetary automatics and DCTs are becoming too good to ignore.

It's not exactly news that certain regions favor certain transmissions.

“There is no doubt that customer preference plays a major role in determining what transmission designs to employ,” says Matthew S. Castiglione, group leader, R&D drivetrain engineering, at Southwest Research Institute's Engine, Emissions and Vehicle Research Div.

“Americans drive vehicles with step-ratio (planetary) automatics. Europeans tend to prefer manual transmissions, and CVTs continue to be important in the Asian market,” Castiglione says. “Another part of the equation is the fact that vehicles in America and Europe tend to be heavier with more powerful engines than in other markets; CVTs do not work well in these types of vehicles.”

Europe's historic predisposition for manuals — currently approaching 80%, according to Stephan Rinderknecht, vice president-research and development at Getrag GmbH & Cie KG — is changing rapidly. Rinderknect says within 10 years, manual-transmission installation rates in Europe will drop to 55%.

As automatics of less than six speeds drop by millions of units, the big gainers are 6-, 7- and 8-speed automatics and DCTs, according to BorgWarner data.

For the domestic auto makers in North America, “automatic” will come to mean a mix of multi-speed planetary automatics and DCTs. The change will happen quickly, because, paradoxically for a region that so strongly slants toward automatics, as recently as 2004, not a single light vehicle built in North America was equipped with an automatic of more than five speeds.

“I think they all (domestic auto makers) will have a certain portion of their portfolio as dual-clutch,” Lacey says.

DCT innovator BorgWarner says it expects production of its DCT modules to increase 500% by 2013, with DCTs coming from five more auto makers in addition to the VW, Audi, Nissan, Bugatti and Shanghai Automotive Industry Corp. brands already using the patented DualTronic technology.

At full launch of announced programs under contract in 2012-2013, BorgWarner says it will provide DualTronic technology for an expected 2.3 million DCTs annually.

Chrysler LLC, for one, will use BorgWarner components for the DCTs it plans to produce in a significant U.S. joint venture with Germany's Getrag Group starting in 2009. This venture, which came as something of a surprise to the transmission community and many industry analysts, is investing $530 million to build an 804,000-sq.-ft. (74,700-sq.-m) plant in Kokomo, IN. The site will make 700,000 DCTs annually.

In fact, Getrag and BorgWarner are teaming all over the world to spread DCT technology. Getrag, in yet another JV (this time with Ford Motor Co. in Slovokia), has invested in manufacturing capacity of some 700,000 DCTs. Production will begin this year for many front- and all-wheel-drive Ford and Volvo vehicles.

Getrag also has retooled a plant in Germany to make DCTs for rear-drive and longitudinal-engine vehicles. One high-profile result: BMW AG's new M DCT transmission — the first-ever DCT from the hallowed performance-car company — is supplied by Getrag (and employs BorgWarner's DualTronic components).

Two other DCT “firsts” worth noting, both of which are coming to the U.S. this year: Nissan Motor Co. Ltd.'s GT-R supercar, in which the Getrag/BorgWarner DCT is the only transmission, muscling out even a conventional manual, the expected choice, and Mitsubishi Motors Corp.'s Lancer Evolution, which Mitsubishi calls the Twin-Clutch Sportronic Shift Transmission.

Getrag said last fall it will produce about 2 million DCTs by 2014, and forecasts a major 4% installation rate in North America by 2010.

“The penetration of the dual-clutch transmissions will increase significantly, both in the U.S. market and the European market,” Mircea Gradu, Chrysler's director-transmission and driveline engineering, told Ward's earlier this year.

The only dissent with Gradu might be in terms of how one defines “significantly.” BorgWarner and Getrag have a clear vision of DCT's rapid advance in the U.S. and Europe, but Michael Paul, ZF executive vice president, flatly says, “We don't see much space for a dual-clutch (transmission) in a conventional car.”

Instead, Paul says ZF sees DCTs as a new-age alternative for manual transmissions driving performance vehicles, retaining the efficiency and sporty characteristics of a clutch-pedal manual transmission while also enabling “automatic” capability.

But for everyday vehicles, ZF clearly thinks the planetary automatic is the choice. Paul calls DCTs “one alternative,” adding, “We don't see it as a replacement for the planetary-type (automatic) transmission.”

Since the dawn of the automobile, the mechanically pure manual transmission has ruled the roost in terms of efficiency. GM's 1940 innovation of the planetary automatic brought comfort and convenience, but its torque converter also introduced plenty of fuel-sapping drag.

Now, an important factor in future transmission implementation is the fact that the relative efficiency of new-technology transmissions is converging around a theoretical optimum overall ratio spread of roughly 6:1.

In effect, today's multi-speed automatics are closing in on the renowned efficiency of the manual transmission — and the DCT for that matter, as the DCT's foundation architecture is that of a conventional manual.

Southwest Research Institute has a longstanding competency in transmission testing and evaluation, and SwRI's Castiglione says, “For contemporary front-wheel-drive 6-speed automatic transmissions, we are seeing maximum efficiencies of around 93% to 94%. For rear-wheel-drive 6-speed automatics, we have measured maximum efficiencies of up to 97%.

“The continued development of electronic pressure controls and torque converter lock-up strategies has increased the efficiencies of transmissions,” he adds. “These developments, along with other design improvements, have allowed the manufacturers to increase the number of gears without reducing efficiency. The addition of more forward gears allows the engine to operate in a narrower speed range, which reduces fuel consumption.”

The end result for today's new generation of multi-speed planetary automatics is remarkable. ZF data shows a striking increase in fuel-efficiency for a 6-speed automatic compared with a 4- or 5-speed. And although we once were told there was little to be gained from expanding beyond six ratios, ZF's figures indicate otherwise.

That explains ZF's pending jump to the 8-speed paradigm, along with Aisin Group, which already has an 8-speed planetary automatic in production for Toyota Motor Corp.'s Lexus Div. These two transmission suppliers, as well as Japan's Jatco Ltd. and OEMs Volkswagen, Ford and GM, all are licensees of the pioneering Lepelletier 6-speed architecture, of which most 7- and 8-speeds will be a derivation.

ZF's Paul says the efficiency of the company's new 8-speed automatic will close the gap with DCTs, which are claimed to be some 10%-15% more efficient than a 6-speed automatic.

ZF unveiled its 8-speed automatic at February's Geneva auto show in intriguing “hybridized” form in the BMW X5 Vision, but a production version isn't expected until sometime next year, perhaps for a '10 model likely to be a BMW.

ZF says the 8-speed employs an “entirely new shifting concept” of four planetary gear sets and five shift elements — and improves fuel economy by 6% over the still-new 6 HP 28 6-speed unit. ZF also says the new unit can handle more torque than its 6-speed automatic, although the 8-speed enjoys similar weight and dimensions.

Significantly, Paul says the 8-speed automatic's overall ratio spread is slightly better than 7:1. He says depending on the torque characteristics of future engines, there may be an opportunity for planetary automatics to move to an even wider ratio spread, but “we are close to the optimum.”

Look for efficiency and performance improvements from DCTs to counter the surge from 8-speed automatics, however.

BorgWarner's Matthes says 7- and 8-speed planetary automatics may catch up to the efficiency of today's 6-speed DCTs, but a second generation will improve on the company's current wet-clutch DCT design with a “humid” architecture with advanced friction materials.

The new gearbox requires much less lubricating oil, while also leveraging higher-pressure control modules, both intended to boost efficiency. With the humid clutch, “we aren't taking a bath, we're taking a shower,” Matthes says in explaining the humid DCT's lubrication strategy.

There could be additional ratios, as well, as is the case with BMW's all-new 7-speed DCT, although Matthes says most vehicles could not make productive use of 7- or 8-speed DCTs.

He says the humid-DCT design also takes the architecture a step closer to the dry clutch, which is more efficient but has much lower torque capacities. Earlier this year, BorgWarner introduced its first dry-clutch DCT, a 7-speed unit going into service for VW.

What about hybridization? ZF (through BMW) unveiled its 8-speed by highlighting its modular design that enables incorporation of an electric motor directly in the transmission. It's likely more multi-speed automatics will include this feature, doubtless inspired by the 2-mode hybrid transmission jointly developed by GM, BMW and the former DaimlerChrysler AG.

But here, Matthes insists the DCT also enjoys an advantage, calling its layout the “perfect link” for a hybrid driveline. He says the design of the DCT, with two input shafts, is ideal for dividing and controlling the separate internal-combustion and electric-drive components of a hybrid.

No single transmission is expected to prevail. But it appears safe to say manual transmissions and CVTs will suffer.

Pre-DCT, the CVT appeared to have a serious future, and the technology does have its places. Nissan sold a not-insignificant 615,000 CVT-equipped vehicles in the U.S., alone, last year, and 1.2 million globally.

But outside Asia, the CVT appears to be fading. While Nissan executives won't go so far as to say Nissan is to CVT as Mazda is to the rotary engine, outside Asia, Nissan is one of a few auto makers to have any significant portion of its transmission portfolio dedicated to CVTs.

“Generally, CVTs operate more efficiently than step (-ratio automatic transmissions) or DCTs, particularly in lower-speed, city-driving cycles,” Nissan engineers say, although admitting, “the advantage at sustained highway speed is much less noticeable.”

And the CVT probably will never match the best automatics and DCTs in terms of efficiency.

“The highest efficiency that we have measured for a push-belt CVT is 85%,” lagging well behind multi-speed automatics and DCTs, says SwRI's Castiglione.

ZF's Paul also relegates CVT to narrow applications, saying, “CVTs will only be surviving in Japan; they are a Japanese specialty.” He also says CVTs are a “relatively expensive solution.”

And although Chrysler pulled the trigger on a high-volume CVT application for its compact cars (Dodge Caliber, Jeep Patriot/Compass), powertrain Vice President Bob Lee told Ward's last fall, shortly after announcing the auto maker's intent to build DCTs with Getrag, that Chrysler is “not that comfortable” with CVTs.

“It's just not realistic (for global applications),” adds Global Insight's Lacey. “The technology and efficiency is outweighed” by 6-speed automatics and DCTs, he says.

It's hard to argue DCTs don't have an edge in the vital area of maximum efficiency, while enabling a wide range of driving-characteristic “tuning” that better suits the coming tightening of fuel-economy and emissions standards.

But the necessary manufacturing investment mitigates against DCTs totally supplanting conventional manual transmissions, as well as automatics. Because DCTs essentially add electrohydraulic control to an existing manual transmission, implementation of DCTs is directly tied to manufacturing capacity for manuals. So again, regional conditions are at play.

“All the investment in North America is planetary automatics,” BorgWarner's Matthes says. “You can't just throw that away.”

He says the DCT makes sense when the choice is replacing an older, 4- or 5-speed automatic or the players have the potential to “start from scratch” — such as the situation with Chrysler's new DCT venture. But the lack of existing manual-transmission production in North America means DCT penetration is certain to proceed much further, much faster, in Europe or in emerging nations where manual transmissions already are produced in high volumes.

Manual transmissions and CVTs are losing out to the improved technology and attractive driving features of multi-speed automatics and DCTs, but the manual won't be banished. Instead, as has been the case for decades, transmission variety will reign.

ZF, for example, with the bulk of its portfolio dedicated to multi-speed planetary automatics, nonetheless is well under way with its own DCT development program. BorgWarner, with major investment in its DualTronic DCT technology, is at the same time working to improve the efficiency of planetary automatics, for which the company supplies all manner of materials and components.

Although Nissan is heavily invested in CVTs, its engineers probably best summarize the situation: “There are several factors that contribute to the selection of a transmission for a particular vehicle. We always weigh factors such as performance, smoothness, cost, efficiency, and customer expectations in a particular segment. Each type of transmission will likely have a place in the Nissan or Infiniti lineup.”

But one thing is certain: The world is edging toward automatic, and the two front runners are the planetary type and DCT. Congestion, tightening fuel-economy standards, emissions regulations and driver preferences are shouting, “Lose the clutch pedal.”

“In the end,” says ZF's Paul, some type of automatic transmission “clearly will save fuel. It's not just the efficiency of the transmission. It's driving behavior.”

ZF Unwraps 8-Speed Automatic Transmission subscribers.WardsAuto.com/ar/zf_automatic_transmission/index.html

Chrysler-Getrag JV Called Promising subscribers.WardsAuto.com/ar/chrysler_getrag_jv/index.html

Audi to Launch 7-Speed, High-Torque DCT subscribers.WardsAuto.com/ar/audi_launch_dct/index.html