A month after new federal guidance on diesel exhaust fluid systems for on-road trucks and off-road equipment were issued, construction equipment manufacturers are quiet on how it might affect their machinery.
The guidance issued from the Environmental Protection Agency would give truck drivers and diesel equipment operators more time before an empty DEF tank or sensor failure causes power losses, also known as derate. The biggest beneficiaries would be long-haul truckers who can experience a sudden drop to 5 mph four hours after a DEF sensor alert. The same goes for heavy-duty diesel pickup trucks.
For offroad construction and farm equipment, four hours after a DEF alert, the machine powers down to idle only. Depending on the machine, getting it running again usually requires additional maintenance beyond refilling the DEF tank.
So far, the trucking and agricultural industries have been the most vocal about the guidance, praising it as ending costly downtime. Truckers won’t have to face being stranded on the roadside, and farmers won’t find their tractors and other equipment cutting out in the fields, their respective advocates say.
As for construction equipment, manufacturers contacted by Equipment World largely declined comment, as did associations that represent them. Some did say they saw the new guidance and were reviewing it to determine what effect it would have.
“We are aware of the new guidance and are working closely with our engine manufacturers to evaluate our systems,” said Nadine Erckenbrack, Bobcat public relations manager. “We will provide updates to dealers and customers as applicable regarding any changes.”
What Does the New DEF Guidance Say?
The derate is part of the EPA’s Tier 4 Final emissions requirements, which were phased in between 2008 and 2015. Since then, DEF has been required on diesel engines over 74 horsepower to cut nitrogen-oxide emissions.
EPA Administrator Lee Zeldin announced the new guidance August 12. It “urges” engine and equipment manufacturers to alter DEF system software in existing vehicles and equipment to prevent the shutdowns, “giving operators more time to repair faults without impacting productivity or safety.”
The guidance also requires new on-road diesel trucks, starting with model year 2027, “be engineered to avoid sudden and severe power loss after running out of DEF.”
The guidance calls for longer warnings before more gradual drops in torque or speed occur.
For off-road construction and farm equipment, no derate would occur until 36 hours after a sensor warning. Then there would be a 25% torque reduction. At 100 hours, torque would be cut in half.
This chart shows the current and new guidance on DEF derate for off-road diesel equipment. *Nonroad constant speed engines (e.g., agricultural pumps) and gensets do not have an initial inducement step as any torque reduction may limit product functionality.
**Nonroad equipment can be restarted with full power 3 times for up to 30 minutes after inducement.EPA
At 4,200 miles or 80 hours, torque would drop 30%.
Speed would not be reduced until 8,400 miles or 160 hours. It would then drop to 25 mph.
For HD pickups, derate would occur at 4,200 miles or 80 hours after sensor alert. After that, top speed drops to 45 mph.
“It is unacceptable that farmers, truckers, construction workers and many other small businesses continually experience failures of diesel-powered equipment when they need it most – costing millions of dollars in lost productivity,” Zeldin said August 12. “Today, we are responding to those concerns by calling on manufacturers to take action to update their software and eliminate the unnecessary sudden loss of power and frustrating shutdowns that too many Americans have experienced.”
The EPA says it is urging engine and equipment manufacturers to follow the new guidance. Such adherence, the agency says, includes developing software updates and “working closely with their customers to identify which engines should be prioritized for new software first and ensuring that customers are aware of this potential update.”
