As the gaps between tractors and trailers shrink through aerodynamic design, making connections safer is only one concern for standards-writing engineers who must account for autonomous trucking in the near future.
The Society of Automotive Engineers (SAE) is developing new standards for hookups that tackle two contentious issues: tractor-trailer interconnection that let the two units communicate, and the best way to electronically couple them to reduce driver injury.
"There is little consensus on a common connector system for the future," said Dave Englebert, chair of the SAE Truck and Bus Brake and Tractor-Trailer Interconnect group. "It is very political."
For example, a global solution is needed to harmonize European trailers that connect with North American tractors sold in Australia, said Matthew Fry, an engineering manager Knorr-Bremse Group AG, the German industrial holding company and parent of Bendix Commercial Vehicle Systems.
"The amount of data is exploding and we need a system that can report back and forth," said Wally Stegall, vice chairman of the future truck group of the Technology and Maintenance Council of the American Trucking Associations (ATA). Tire pressure monitoring systems, door sensors, solar panels, and wireless temperature sensors are just a few of the data sources.
Englebert, Fry and Stegall spoke at the recent SAE COMVEC Technology Connection meeting in Indianapolis.
"Anytime you try to create standards, it's hard to get everybody to agree," said Mike Roeth, executive director of the North American Council for Freight Efficiency (NACFE). "But that's not a reason not to do it."
Compatibility counts
An SAE task force reviewing voltage systems used by North American heavy-duty truck manufacturers recommended in October 2018 that 12-volt direct current should be used with the interface governed by existing SAE standards. The task force said 24- or 48-volt DC connectors should be options based on demand.
With many truck makers pledging to offer high-voltage battery-electric trucks for sale early in the next decade, a new standard probably will be needed.
Kenworth Truck Co., which is working with Toyota Motor Corp. on an experimental fleet of 10 hydrogen-powered fuel cell electric heavy-duty trucks, is using 48-volt power systems to run cooling fans and pumps, said Brian Lindgren, Kenworth director of research and development.
Volvo Trucks North America has twin 12-volt battery systems on its retrofitted battery-electric VNR day cab model that it will sell in selected states beginning in 2021.