SAE Updates Truck Standards for Wide Variety of Systems

New and updated standards from SAE International involving handling maneuvers, braking, corrosion testing, electrical systems and windshield wipers are expected to again have a significant effect on the trucking industry, several industry experts and manufacturers have said.

Although SAE International — previously known as the Society of Automotive Engineers International — is not a regulating body, the standards it adopts are more influential in many ways than the mandates handed down by regulators. That’s because the standards often are established by the manufacturers and engineers who will be putting them into action — and in many cases, the standards drive federal regulations.

“SAE provides a list of standards based on best engineering practices,” said Jesus Gomez, who served as director of engineering for Western Star Trucks, a unit of Daimler Trucks North America, Portland, Ore., until April 2011. DTNA also is the parent company of Freightliner Trucks.

“SAE does not set regulatory guidelines,” said Gomez, now manager of the CEO office at DTNA. “However, SAE’s set of best practices do influence regulatory bodies, like [the California Air Resources Board, the U.S. Environmental Protection Agency and the National Highway Traffic Safety Administration], which in turn affect manufacturing when prescribed by the regulatory bodies.”

SAE committees, which work on design and adopting the standards that the industry typically embraces, consist of engineers who often seek to achieve the same goals for their companies — whether technological breakthroughs or a particular type of testing parameter. Any given SAE committee usually has several steering committees and technical subcommittees that formulate the so-called “J-documents” that contain the standards.

The Truck and Bus Committee, which oversees 234 J-documents, has steering committees for: brake and stability control; advanced and hybrid powertrain; body and occupant environment; total vehicle; and electrical/electric. Technical committees work under the steering committees and draft the standards.

SAE regularly holds symposiums, congresses and other meetings, but they are not necessarily a precursor to the adoption of new standards. The upcoming Heavy Truck Handling, Dynamics & Control Symposium — scheduled for May 15-17 at the Michelin Americas Truck Tires facility in Greenville, N.C. — will include discussions of issues that may be under consideration for new standards.

One example on the agenda this year will be a presentation by Mehdi Ahmadian, a professor of mechanical engineering at Virginia Tech, where he also is director of the Center for Vehicle Systems and Safety. Ahmadian, chairman of the SAE Chassis and Suspensions Committee, will discuss the engineering and development of heavy truck handling dynamics and control.

“Some of the issues and some of the standards related to electronic stability control of heavy trucks are going to be quite significant for us as we go forward,” he said. “A lot of companies are developing or have electronic control systems in their new production.”

Ahmadian said standards also may be developed for maneuverability of heavy trucks.

“We may see standardization of dynamic maneuvers adopted across the industry for handling maneuvers, very similar to what has been done with passenger vehicles,” Ahmadian said, “except that the requirements for heavy trucks are different in terms of their dynamics and all the other issues they have.”

Alan Korn, director of vehicle dynamics and control for Meritor Wabco, Troy, Mich., also will be presenting on stability control — with an emphasis on tractors. Korn said he expects a rule from NHTSA that will mandate stability controls on tractors and motor coaches, and he intends to use his presentation to prepare the industry for the actions it will need to take.

“We don’t know with 100% certainty, but what we believe is that [a possible NHTSA rule] will require stability control to be installed on all new tractors, air-brake tractors and motor coaches,” he said. “Upon the implementation date — which could be sometime in 2014 — all new vehicles that meet that criteria will have to be fitted with stability control.”

Korn said SAE has no current standard on which the new rule might be based, but he indicated a standard could follow the rule.

“What might happen is, once people put their heads together, there will be a requirement within the notice of proposed rulemaking,” he said. “Whether that standard is accepted or an alternative is considered, once that’s resolved, perhaps a standard will be adopted.”

Gomez said he expects federal regulations on certain maneuvers, particularly those related to braking distance, to be influenced by new standards that may come out of SAE.

“Anything like standards on braking and distance, or capacities with vehicles loaded or unloaded, has been affected by the influence between SAE and regulations in the past, and I imagine that would continue to be true,” he said.

But the United States is not the only country, or even the first, to respond to standards that come out of SAE. Gomez said that DTNA is one of several manufacturers trying to stay ahead of the curve on such technologies.

“There are different countries where there are regulations with respect to vehicle proximity,” Gomez said. “When you approach a vehicle at certain speed, the vehicle takes over the braking of the vehicle, and we do have that technology in our vehicles. Some of the most significant developments for any OEM are precisely with regard to vehicle safety — and then they become safety standards.”

In January, SAE established a new standard for testing procedures on driveline parking brakes used in medium-duty vehicles.

The recommended procedure tests friction-based parking brake components used in conjunction with hydraulic service-braked vehicles with a gross weight rating heavier than 10,000 pounds. The test procedures apply to both brake-related and actuation-related testing but not to application dashboard switches or indicators.

For corrosion testing of commercial vehicle components, the SAE Truck & Bus Corrosion Committee issued a revision in November to the J2721 standard originally issued in 2009. The revision updates recommended practices to validate acceptable corrosion performance for metallic components and assemblies on medium and heavy trucks, as well as bus and trailer applications. It spells out various testing procedures for components in various locations within vehicles and incorporates cyclical conditions including corrosive chemicals, drying, humidity and abrasive exposure.

The J2721 standard was developed originally to address corrosion related to factors such as de-icing chemicals, temperature extremes, abrasion and mechanical stress. However, the standard does not address the chemistry of corrosion or methods of corrosion prevention — leaving these matters to J447, a related standard.

As electric vehicles gain prominence, SAE already has developed a standard for EV batteries and soon may be developing a standard for noise — or lack of it — from electric vehicles.

The battery standard, J2929, published in February 2011, defines safety criteria for lithium-based rechargeable battery systems as energy storage systems connected to high-voltage power trains. The standard, considered to be minimal, may result in battery-system and vehicle manufacturers coming up with additional requirements for the development of a safe battery system.

SAE also is considering the development of a standard for noise from electric vehicles, said Steve Schrier, a spokesman for Navistar Inc., the manufacturer of International trucks based in Warrenville, Ill. The focus of the standard is not to eliminate noise but to generate more of it for the safety of those who may not hear the approach of an unusually quiet electric vehicle.

“They’re so quiet that they come down the alleyway, and people don’t realize they’re there,” Schrier said.

SAE has been working since January 2011 with the National Fire Protection Association on an electric vehicle safety training initiative, and SAE’s Ground Vehicle Standards Technical Committee is developing a variety of standards to ensure safe implementation of EVs and hybrids.

Another possible standard revision has been under discussion in the Environmental Standards Task Force of the SAE Truck and Bus committee, whose chairman is Gary Yurko of Tyco Electronics, Harrisburg, Pa. The committee met on March 29 to consider updating the standard on recommended environmental practices for electronic equipment design in heavy-duty vehicle applications.

The committee did not take any action in March, but an SAE spokesman said the members will continue to discuss revising the standard, first established in 1988 and revised several times since then. The standard concerns the range of environments that influence the performance and reliability of electronic equipment designed for heavy-duty and off-road vehicles.

Other recently issued standards for trucks and buses include an inertia brake dynamometer test procedure for vehicles weighing more than 10,000 pounds and equipped with hydraulic service brakes.

Issued Nov. 10, the standard calls for two main test sequences. The first is a development test sequence for generic test conditions when specific vehicle parameters are not known. The second is a test sequence that can be applied when more specific information is available — such as brake pressure as a function of brake pedal input force, or vehicle-specific loading and brake distribution information.

SAE also announced a revision of its standard on truck and bus windshield wipers systems — a revision of a standard most recently reaffirmed in 2000.

The revision establishes minimum performance requirements and uniform test procedures for windshield wiper systems, but it applies only to tests that can be performed in commercially available laboratories.

However, not every aspect of commercial vehicle transportation requires new or annually revised standards. For example, NHTSA is considering speed ratings on heavy truck tires, but the SAE Truck and Bus Tire Committee is not considering any new standards on that issue.

The most recent SAE standard on truck and bus tires, published in October 2010, concerned testing methods for the determination of heavy-truck tire force and moment properties under combined cornering and braking conditions.

Tire manufacturers use an International Organization for Standardization, or ISO, “service description” marking/labeling convention — consisting of “load index” and “speed symbol” — to comply with many regulations in effect outside the United States. At present, an SAE spokesman said, the U.S. Department of Transportation has not adopted the ISO service description on truck and bus tires for regulatory purposes.

SAE standard J844, revised four times since its original adoption in 1963, concerns compliance specifications for tubes and fittings. Federal requirements for the “load range” of truck and bus tires are based partly on that standard — although the most recent revision of the federal requirements removed its previous reference back to SAE.

Current NHTSA requirements for truck and bus tires call for tires rated for 55 mph or less to be marked with their maximum speed rating.

Truck manufacturers say that SAE standards rarely present a challenge for them to react or take special measures to meet them because they serve on the committees that set the standards — and usually base the standards on the priorities they already are pursuing.

For example, Schrier said, Navistar usually is working on a given standard before SAE adopts it.

“From a standards perspective, we’re meeting the standard that the customer is demanding anyway,” he said, “so we work closely with the people who are developing the standards.”

Gomez said that Daimler sponsored the most recent SAE Vehicle Engineering Congress, held in Chicago in November, and that Daimler employees are chairmen of a wide array of SAE committees.

Other items to be discussed at the May symposium in Greenville include:

• Findings from the past five years of research on heavy vehicle roll stability by the National Transportation Research Center.

• The status of NHTSA research and rulemaking on heavy vehicle electronic stability control.

• An update on onboard safety systems research from the Federal Motor Carrier Safety Administration.

• The future of new-generation wide-base single tires.

• The latest on commercial vehicle chassis, control systems and active safety systems.

• An assessment of ride in a heavy commercial truck using numerical simulation methods.

• A look at active steering of heavy goods vehicles under the category of control and testing.

• A discussion of predictive vehicle stability control with tire force saturation management.