With more integrated powertrain choices than ever, Fleet Equipment dived into the offerings to give you the lowdown on what’s out there, what’s new for 2017, and how it all works together.
How it works
Let’s get right into the specifics of integrated powertrains—how do engines “talk” to transmissions that are part of the integrated powertrain as opposed to other transmissions? We put this question to our OEM/OE sources.
“When we talk about deep integration, a big part of that is enabled by the J1939 data link. As AMTs entered the market, we’ve progressed our use of this communication protocol,” said Alex Stucky, product strategy manager of commercial powertrain for Eaton. “It’s a deeply optimized package. We’re sharing data, both public and proprietary that allows us to see where the most efficient operating range of the engine is. Visibility to engine operating conditions allows us to make software and shift logic adjustments to operate within a specific range of the fuel map, balancing performance and fuel economy.”
“Peterbilt works closely with its supplier partners to ensure top performance of every component and every system with an approach of complete vehicle integration,” said Anthony Gansle, marketing manager of on-highway products for Peterbilt Motors Co. “With the Model 579 Epiq’s standard powertrain–which utilizes a PACCAR MX engine with the Eaton Fuller Advantage automated transmission—we developed proprietary communication technology between the two components that, in combination with advanced aerodynamics and other features, can improve fuel efficiency by up to 14%. The software precisely adjusts RPMs and shift patterns for the best performance based on operating conditions and application. Additionally, this powertrain is integrated with other truck systems and Peterbilt technologies, such as Predictive Cruise, that utilizes this optimized communication for even greater fuel economy gains.”
“The Motor Control Module [MCM] and Transmission Control Module [TCM] provide inputs to the Common Powertrain Controller [CPC],” explained Kelly Gedert, manager of powertrain and components marketing for Daimler Trucks North America. “This dedicated powertrain communication network allows the transmission and engine to share information to optimize efficiency throughout the entire powertrain.”
“Using the reliable J1939 vehicle network, we share information that allows communication of proprietary messages,” explained Mario Sanchez, Cummins’ director of marketing communications. “This streamlines the processing of signals and decisions made by both electronic control module of the engine and transmission. There is also communication and comparison of conditional inputs that helps us to refine the control output.”
“As the engine and transmission are both proprietary products,” said began Scott Barraclough, technology product manager for Mack Trucks, “there is complete transparency between the components. The transmission knows the fuel mapping for the engine, enabling it to be in precisely the right gear for maximum fuel economy and performance. In addition to the engine, the mDrive is also able to communicate with other electronic control units [ECUs] throughout the truck, further maximizing performance and efficiency.”
Downspeeding is basically the process of programming the engine to run at a lower cruise RPM so that it uses less fuel. Running at lower RPMs also helps trucks and engines meet emissions regulations.
“Faster data sharing provides swift and more precise control of the operation, enabling more operating time within the sweet spot where engine is producing peak torque with less fuel,” Cummins’ Sanchez said. “This increases the amount of shifting, but there is no fatigue concern and the engine calibration is optimized with quick transition back to steady state. We also share critical information on input and output capability for optimal matching of engine performance and gear ratios. Validation is in process to leverage this capability even more, cruising at 975-1,100 RPMs is coming soon.”
“By communicating more effectively as integrated proprietary components, the powertrain allows for smoother shifting, more precise transmission shift points, and more exact communication with the engine to keep the RPMs in the fuel economy sweet spot while maintaining the required torque levels,” Daimler’s Gedert explained.
“The 2017 PACCAR MX engines achieve peak torque at 900 RPM,” Peterbilt’s Gansle said. “This peak torque rating maximizes downspeeding capabilities to meet a wide range of customer operating and business requirements.”
The relationship between the engine and axle is crucial for optimum downspeeding results, which is where integrated powertrains that include axles have an extra advantage.
“The mDrive AMT and the low RPM performance of our Mack MP engines have been the enablers for downspeeding for years,” Mack’s Barraclough said. “There are new axle ratios that will be available in the 2.2-2.3x range, allowing us to expand our Super Econodyne package offering to include the direct drive mDrive transmission. Until now, the Super Econodyne has been available exclusively with overdrive transmissions.”
“In January 2017, Detroit will release a 2.28 rear axle ratio in the 6×4 Integrated Detroit Powertrain package, and in mid-2017 will make an even faster 2.16 rear axle ratio available for the 6×4 Integrated Detroit Powertrain packages,” Gedert said.
The advent of automated manual transmissions has changed the possibilities available to powertrain manufacturers.
“AMT technology has allowed us to develop powertrain solutions well beyond our traditional integration constraints. The real-time data analysis and precise controllability of our AMT allows us to deliver consistent and efficient performance,” said Eaton’s Stucky. “AMT and engine integration activity has allowed optimization and feature development previously limited by mechanical technologies.
“We’ve expanded beyond product integration to include partners in our service and diagnostic strategies, with the end goal being the best service solutions to customers,” Stucky continued. “For example, Eaton and Cummins have expanded service cross-training efforts, so service reps are being trained on both engine and transmission processes. We’ve combined many CumminsCare and Eaton RoadRanger support network activities. These efforts provide a streamlined approach to powertrain troubleshooting—our representatives’ work together to determine root cause and direct customers to the right experts without delay.”