MANAGER: Jeff Bush
TITLE: National fleet purchasing manager
FLEET: Nestlé Waters North America, Brea, CA
OPERATION: Nationwide fleet of more than 4,000 vehicles
When a fleet manager gets tasked with testing alternatively powered vehicles — everything from diesel-electric hybrids to compressed natural gas (CNG) and even hydrogen-powered fuel cells — the worries extend far beyond simply dealing with significantly higher sticker prices. In particular, fleets putting alternative vehicles on the street also closely monitor two other critical criteria: operational benefits/drawbacks and maintenance needs.
Maintenance in particular can be a dicey area for many forms of alternative propulsion commercial trucks. Since they are so new to the industry, information on upkeep comes from the laboratory and test track, not so much from real-world experience.
That proved to be one of the issues facing national fleet purchasing manager Jeff Bush and Nestlé Waters North America (NWNA) when they decided to add diesel-electric hybrid trucks to their fleet of 4,000, which includes CNG utility customer service vans and 32 hydrogen fuel cell forklifts. The new medium-duty diesel-electric trucks, configured with both dry van and beverage delivery bodies, help in the delivery of product, primarily bottled water, across the U.S.
Bush is a U.S. Navy graduate and 24-year veteran of the U.S. Marine Corps as a fixed wing aviator. So when it came time to examine the maintenance needs of diesel-electric hybrid trucks, he made sure to cover all the bases.
“Our trucks are equipped with the Eaton parallel electric-hybrid drive system, so their personnel came in to help train our technicians and drivers,” he explains. Specialized training isn't anything special or new to NWNA's diverse fleet. Yet its Freightliner Business Class M2e diesel-electric hybrid trucks offered some unique challenges. For starters, Eaton counseled NWNA's technicians to leave much of the vehicle's propulsion system — from the electric motor and transmission to the battery pack — untouched during preventive maintenance checks.
NWNA quickly found that the position of the power electrics carrier, or “PEC,” which contains the hybrid system's battery, affected truck loading and unloading operations. “We instructed our forklift operators to be very careful loading and unloading these vehicles as they'd be placing heavy cases right over the area where this component is located,” Bush says.
While NWNA's M2e vehicles are getting 25 to 35% better fuel economy as expected, maintenance benefits and drawbacks are only now beginning to surface. “We were told to expect longer brake life as a side benefit of the hybrid system, and for those hybrid trucks now reaching three years of age, we're beginning to see that,” Bush notes. “Our technicians are telling me these trucks are right at the point when they'd typically be changing brake pads, yet they're finding they still have more miles to go.”
Another benefit is there seems to be less heat wear on the truck's diesel engine. The hybrid system allows the engine to rev up slower with less strain and thus produce less heat. Bush cautions, however, that this benefit may be a double-edged sword over time.
“The downside is that if the engine doesn't generate enough heat, the emissions system may be forced to conduct more active regeneration events to clean the diesel particulate filter,” he explains. “More active regenerations means stopping the vehicle and burning more fuel,” Bush notes. “This is a situation we'll just keep watching as these vehicles accumulate more time and miles.”