Equipment World Digital Magazine
Issue link: https://read.dmtmag.com/i/139700
trucks | continued Eaton's UltraShift Plus high rolling resistance, or having smooth, controllable startup power in front of a paver, an automatic transmission is the better choice in Caterpillar's estimation. "You just cannot beat a torque converter in those applications when it comes to maintaining 100 percent boost engine power up and down through the gears," he says. "Additionally, there's not a dry clutch to be abused or overheat because an automatic is 100-percent fluid drive power. So that's where we see the advantages of a torque convertor automatic. However, in a steady-state cruise application in pure highway mode, you simply cannot beat an automated manual: They really shine in those applications." The case for automatics Despite their reputation as slow to change, it appears users are gravitating toward automatic transmissions in surprisingly high numbers. McKenna, for example, says the mDrive take rate in Pinnacle tractors is currently in the neighborhood of 38 percent, which aligns with other OEMs. In some medium duty applications, AMTs are now spec'd in over half of new trucks sold. Likewise, Saxman says that well over 50 percent of all new Volvos sold this year have been spec'd with the company's iShift AMT. There are several reasons for this significant shift. Shane Groner is manager of product development, NAFTA, for Eaton. He says currently the company's UltraShift Plus AMT is enjoying a 25 percent take rate in heavy-duty trucking applications – with on-highway applications logging in around 15 percent. "There are still a lot of highly experienced drivers out there that can get the most out of manual transmission," Groner says. "And those gearboxes are essentially bulletproof. So if you're blessed with an abundance of experienced drivers and upfront costs are still your primary expense driver, then it's hard to argue with manual transmissions." The appeal of automatics can go far beyond driver preferences, with safety and fuel economy topping the list. "Automatics allow less skilled (novice) drivers to be productive," says Steve Spurlin, executive director, international application engineering and vehicle integration for Allison Transmission. "They are also a large help with safety because the drivers can stay focused on the road or the task at hand instead of shifting gears. Additionally, drivers do not get as fatigued with an automatic as they do with a manual or AMT since they do not have to shift gears all of the time." "The way you spec a drivetrain is changing and automatic transmissions are a key part of that formula," says Brad Williamson, powertrain marketing manager for Daimler Trucks North America. "The industry at large is now spec'ing lower gear ratios with direct drive powertrains becoming more common." At the same time, Williamson says, the concept of "downspeeding" – or operating a diesel at lower rpms while at cruise speeds are being driven by the push for better fuel economy. "An automatic transmission can do these things better than all but the best drivers out there. Because information is key: If you designed both the engine and the transmission, then they can 'talk' to one another and share critical information. And the transmission can manage all this information and deliver the best performance possible given all those criteria. A driver just can't do that consistently." Williamson's point is important because it addresses the latest development in the evolution of automatics in heavy-duty trucking: complete powertrain integration. To date, Volvo, Mack, Daimler and Eaton (with a just-announced partnership with Cummins) have all developed highly integrated powertrains that share unprecedented levels of proprietary information between the engine and transmission to consistently deliver optimal fuel economy at all times. "It all boils down to the electronics," McKenna argues. "When you have Vendor A supplying the engine and Vendor B supplying a transmission, rarely do those two components share 100 percent of their information 100 percent of the time. Typically, the transmission in those instances ends up making decisions with about 75 percent of the data it needs to make an optimal shift. " Eaton's Groner says that a fully-integrated drivetrain can boost fuel economy from 3 to 6 percent above what a vehicle with a non-integrated drivetrain achieves. "And that's with an EPA 2013 engine," he adds. "Our testing shows those numbers are even higher on EPA '10 engines." EW 54 July 2013 | EquipmentWorld.com EW0713_Trucks.indd 54 6/24/13 11:09 AM