In addition to wasted fuel, high idle times can result in a wide range of increased expenses. Excessive idling also increases the risk of unscheduled, manual regens of aftermarket equipment, which can eat up valuable driver time. What’s more, most states have idling regulations.
Today’s aftermarket equipment makes it even more important to reduce idling. When idling, the vehicle is not operating at the ideal temperatures that allow soot to burn-off of the diesel particulate filter. “That buildup makes things harder to clean and can create the need for the driver to do a manual, parked burn-off,” said Mike Hasinec, vice president of maintenance support for Penske Truck Leasing.
That burn-off, which is also called a regen, typically takes around 20 to 30 minutes when done regularly but can take up to 40 minutes if the vehicle has experienced a lot of idling. Pressure drives regens. “You have an inlet and outlet pressure reading. When the pressure gets too large, it calls for a regen,” Hasinec said.
While it can be tempting for a driver to start and then abort a regen in order to get back on the road, it can lead to bigger problems. “They’ll start it and abort it not realizing that it is doing more damage,” Hasinec said.
Once a regen starts, the soot begins to burn off. If it isn’t completed, it can pack into the walls of the filter, creating hot spots that can eventually lead to cracking. “It is comparable to when you get flash fires in your chimney because you haven’t kept it clean,” Hasinec said.
In addition to damaging a filter, aborting a regen can degrade fuel economy. “As the filter fills with soot, fuel economy can decrease due to the back pressure. Also, the system will take the back pressure and think there is a heavy buildup of soot and it will call for more frequent regens,” Hasinec said.
One of the most important elements of protecting fuel economy and the aftermarket equipment is for drivers to pay attention to the dash lamps. “Those lamps are telling you that the truck needs help,” Hasinec said. “We have heard horror stories that dispatch will tell the driver to ignore the lamp until they break down. If they’re broken down on the side of the road and needing a tow, it creates far more timing issues and complications for our customers.”
Hasinec said there is a misconception that regens decrease the life of the DPF, but that isn’t true.
Reducing idling not only protects equipment and fuel economy but also enables drivers to comply with government regulations. Most states have idling restrictions, and violating the laws can result in hefty fines. The American Transportation Research Institute has tracked 60 state and local regulations related to idling.
Reducing idling typically starts with understanding driver behavior, and Penske can work with customers to identify driver idle time through data coming off of the engine. Fleets can then use the data to understand if the idling is driven by an application issue.
Customers in certain applications may require higher idle times, and Penske can work with customers to create either a pre- or post-trip strategy that allows drivers to complete a regen that doesn’t interrupt their daily route or service and keeps the filter clean. Regular regens can also shorten the amount of time the regen takes.
“We have customers that can’t reduce their idling, but there are different calibrations you can put on the truck that allow for that and can create more parked regen requests or allow the driver to run a regen more frequently,” Hasinec said. “Even when there is an application issue, there are things you can do to have a scheduled regen event during pre-trip or post-trip.”
If drivers are idling to stay comfortable during rest periods, the fleet could consider spec’ing an auxiliary power unit. Hasinec said APUs cost anywhere from $7,000 to $12,000. However, that cost is easily recovered in fuel savings alone, he said. “In a normal week, a driver spends 40 hours in the sleeper berth. You’re going to burn an average of 1 to 1.2 gallons per hour idling,” he explained.
Given the price of diesel, that could add up to about $147 a week. “ROI from a fuel perspective takes about a year and a half,” Hasinec said.