Government regulations are prompting a changeover to electric powertrains, with early growth coming in commercial vehicle applications where range and recharging are more easily managed. Greater expansion will require revisions in maintenance and broader availability of charging stations as well as improved driving ranges.
Electric vehicle (EV) introductions are coming at a rapid pace, and major fleet owners like Penske and Amazon are placing significant orders. ABI Research predicts that commercial-vehicle shipments will hit 3 million units worldwide by 2024. That’s a strong 28% growth rate over the next five years. Most of that expansion will come in operations with planned routes and home-base charging, according to ABI.
While rapid growth is expected, program managers are moving cautiously. Buyers and drivers are still leery about moving away from rapidly improving internal-combustion engines. Electric power system developers are pushing the limits of technology to make battery power more attractive to buyers.
“Electrification is an investment in the future. You have to invest, but you need to be realistic about profits,” Shelley Knust, executive director, off-highway engineering at Cummins, said during the recent SAE COMVEC Technology Connection in Indianapolis.
Design teams are looking at a range of technologies that can help them improve EV driving distances. One is connectivity, which is expected to become an important element in the push to extend EV ranges. Coupled with GPS data, it can help drivers determine optimal routes for energy conservation and help systems account for hills and curves.
“The synergy between electrification, autonomy and interconnectivity technologies will likely revolutionize overall vehicle efficiency,” said Tom Carlill, Caterpillar’s new-product introduction program manager. “A connected vehicle that is aware of its surroundings via onboard sensors and real-time GPS position data can anticipate load requirements and continually adjust engine output to maximize overall efficiency. If it’s electrically powered, the job can be done with a smaller battery. And, if it’s a hybrid, the machine can select the power source most appropriate to the task in real time to maximize efficiency.”
Shifting fleets to hybrid and pure EV powertrains requires many changes in both product and infrastructure development. Keeping batteries charged is a major challenge for commercial vehicles. Engineers are using several strategies to extend operating ranges. Regeneration can provide major benefits regardless of the size of the vehicle.
“In rail, regeneration is already in use; they’re already seeing 25% reduction in energy consumption,” said Scott Woodruff, director of global mining at MTU America Inc. “We want to bring those benefits to commercial trucks.”
The availability of charging stations is a bigger issue. Fast chargers are still evolving, and rollouts for all types of charging stations remain sluggish. Many suppliers and fleet owners are turning to partnerships to ensure that charging stations meet usage requirements.
“Infrastructure is one of the biggest challenges,” said Tony Heaton, head of battery systems at Nikola. “Part of our business model is to go wells to wheels, focusing on control hardware and working with partners like Anheuser-Busch. The number of charging systems will grow fairly quickly.”
Fleet owners will need to consider that charging infrastructure when they begin buying EVs. Ensuring that trucking routes have necessary charging stations will be a concern as stations are built to meet demand. The North American Council for Freight Efficiency (NACFE) predicts that in the near term, many electric trucks will be used in areas where they recharge at depots or their home base.
NACFE predicts that for the foreseeable future, fleets will need a sophisticated understanding of the infrastructure, rates, duty cycles and times available for charging, suggesting that fleets invest in networked charging software and services. Fleet owners should also work closely with local utilities and charging system providers in their area.
Refurbishing maintenance programs
As drivers and owners grapple with charging, they’ll also need to rework their maintenance operations. This aspect of the infrastructure will change dramatically with the shift from pistons and cylinder blocks to inverters and battery controls.
“When electrified powertrains are deployed, it will require training for dealers, maintenance personnel and even users,” said Michael Weinert, VP of engineering at John Deere. “You want maintenance technicians to be highly efficient in the diagnosis of electronic parts—they are very expensive. We don’t want a lot of parts returned with no faults found.”
EV proponents note that many maintenance tasks become simpler as that changeover occurs. “EVs are easy to maintain,” said Varoujan Sarkissian, head of electrical and control systems at Nikola. “There aren’t as many parts, and you don’t need maintenance like oil changes. But we do need to understand high-voltage implications; we need to work with owners and maintenance people to make sure they’re not in danger.”
Floating the idea of hydrogen
Development in electrification is often dovetailed with research in hydrogen fuel cells. Cummins’ Knust noted that “some vehicles may leapfrog the hybrid phase and move directly to hydrogen.”
The programs can be linked because fuel cell systems can use batteries to store energy, much like a conventional hybrid. They also use electric motors. That can make it comparatively easy to convert a battery-powered system to a fuel cell design.
“Our fuel cell vehicle is a hybrid—if you take the fuel cell out and expand the battery pack, you have an electric vehicle,” said Dane Davis, Nikola’s chief technical officer. “The drivetrain stays the same, the motors and inverters don’t change.”
Components head off-highway
Just as truck developers can leverage advances made in electrification technologies for passenger cars, engineers designing electrified powertrains for off-highway equipment plan to leverage advances in on-highway vehicles. But in many off-highway designs, additional ruggedization will be needed.
Power electronics and motors for commercial trucks will typically have longer lifetimes and tougher environmental requirements than components used in passenger cars. Off-highway vehicles have even more stringent reliability requirements, but they don’t have large enough volumes to attract much attention from component manufacturers. That’s expected to change when the markets for inverters, power devices and other components used in electrified powertrains rise, prompting more component development programs to focus on commercial markets. Until then, companies will be on their own in the effort to meet harsh environmental requirements.
“On-highway equipment needs to be hardened before it can be used in off-highway machines,” said Deere's Weinert. “Volumes are low for off-highway applications; they’re even lower when you’re going to electrification components. Volumes will be quite low during the transition to electrified powertrains.”
Hardening enclosures is one of the simplest ways to ruggedize equipment. Nikola Motor Co. is taking this approach as it races to get electric and hydrogen fuel-cell powertrains ready for on- and off-highway vehicles. One goal is to use the same circuit boards in as many systems as possible.
“Off-road vehicles have severe environmental requirements for connectors and components,” said Nikola's Sarkissian. “Some parts in our off-road vehicles get submerged; they need to meet strict regulations. We want a family of products that serve both markets so we can use the same products. We use different seals, different connectors and different enclosures so we don’t have to change the electronics.”
However, the expansion of battery power will come at a fairly slow pace. Many off-highway markets have already changed over, but the rate of change will be slow for many of the remaining applications. It’s hard for batteries to compete with diesel power.
“We’ll see dominance by diesels for the next several decades; it can be three to five times the cost for a full-electric vehicle versus diesel,” said Cummins' Knust. “We will have first adopters, people who will pay more. But for the bulk of the market, cost is a big factor.”Continue reading »