Clean Diesel – Diesel Technology

How Retrofitting Fits in Today’s Fleets

November 2009, Green Fleet Magazine - Feature

by Chad Simon

Imagine taking an old medium-duty diesel truck from its deathbed, gutting it, and retrofitting it with a brand-new Cummins diesel engine, transmission, aftertreatment system, and Eaton hybrid-electric system, thus giving it another 10 years of useful life. Through Freightliner Custom Chassis Corporation's (FCCC) hybrid-electric retrofit program, this "resurrection" can be arranged at a cost less than purchasing a brand-new truck, according to Mike Stark, FCCC alternative fuels program manager. 

Fleet managers who implement retrofit units in their fleets benefit not only from federal tax credits and greater fuel efficiency, but also by the knowledge they're offsetting their own carbon footprints and setting an example for other fleets to follow. 

FCCC's HEV Program Grows

FCCC began manufacturing hybrid-electric chassis in 2001, sending the first 18 prototypes to various locations in the U.S. for fleet evaluation. 

Since then, the Gaffney, S.C.-based subsidiary of Daimler Trucks North America LLC has sold close to 400 hybrid-electric units to large delivery companies, according to Stark. FCCC manufactures premium chassis for the delivery walk-in van and shuttle bus markets, as well for motor homes and school buses. 

FCCC's hybrid-electric chassis, which features a diesel engine coupled to an electric motor/generator and lithium-ion batteries, works in conjunction with the engine and transmission, enabling seamless operation incorporating electric and diesel power. 

Lithium-ion batteries capture and store energy during the regenerative braking phase of the vehicle's operation. The batteries are constantly charged throughout the diesel engine's operation, eliminating the need to plug into an electrical source. Both the engine and electric motor can provide power to the drivetrain. The sophisticated hybrid supervisory controller selects the most efficient mode of operation - either diesel or electric - depending upon current operating conditions and driver demand. 

Evaluating the Technology

Several hybrid-electric chassis prototypes were recently delivered to FedEx through a partnership between FCCC and the nationwide delivery company to validate the technology, evaluate performance, test the hybrid-electric system's reliability, and determine its practicality for fleet use. 

So far, the prototypes have a cumulative 98-percent reliability rating. When the vehicles are sent out to a morning job, they return at night without experiencing problems. In addition, the units average about a 45-percent increase in fuel economy, and brake pad life is extended 3-4 times because of the hybrid's regenerative braking feature.

To evaluate the hybrid system in-house, FCCC runs two vehicles - one hybrid and one gasoline - in the same general route area. The performance of the two trucks is measured in as close to their operating environment as possible. 

"We want to compare apples to apples by likening a six-cylinder diesel to another six-cylinder diesel," Stark said. "We're not comparing a diesel engine to a gasoline engine. Our six-cylinder diesel vehicles today get anywhere from 10-13 mpg; now add 45 percent on top of that number, and that's what the hybrids get." 

Retrofit Program Launched

FCCC launched its hybrid-electric retrofit program in November 2008 with several objectives in mind. One objective was to increase the population of hybrid-electric vehicles in fleet service. Another aimed to modify older medium-duty diesel trucks with mileage up to 300,000 to bring them up to EPA 2007 emissions standards. The current standards apply until new emissions regulations kick in Jan. 1. 

Another objective was to take vehicles earmarked for potential retirement and extend service lives another 7-10 years with a new engine and hybrid system retrofit. 

Since the program launch, FCCC has removed the engines, transmissions, wire harnesses, and exhaust systems in 92 MT-45 walk-in van chassis, replacing those components with new 2007 Cummins 200-hp ISB engines with aftertreatment systems and Eaton hybrid-electric systems, complete with the instrumentation, electronics, and cooling systems. 

The trucks were also repainted and returned to like-new condition. All 92 trucks were deployed to FedEx's California fleet as part of a corporate strategy to meet California Air Resource Board (CARB) requirements. One vehicle takes about 30 hours to retrofit. 

"It's a slow-moving process, but there's a plan to steadily increase that number as we move forward. Once the retrofitted vehicles have been validated in their fleet for reliability and productivity, FCCC will increase that number steadily to 200 and eventually up to 300," Stark said. 

Retrofitting Is Cheaper

According to Stark, it's less expensive to retrofit an older truck than to purchase a brand-new unit. The body, base chassis, frame rails, cross members, and engine mount remain intact and don't need to be replaced, so fleet managers save the cost of these components. 

Expenses include retrofit labor costs and the price of the Eaton system. In comparing the overall cost structure of the vehicle itself, the goal is not to increase the number of trucks in a fleet, but upgrade those trucks to gain the efficiency and benefits of the hybrid-electric system, according to FCCC.

In the midst of complying with the new 2010 diesel emissions regulations, FCCC has seen significant interest in the hybrid-electric retrofit program from commercial fleet users.

"We're not prepared to go forward with this program on a one- or two-vehicle basis; we want to package retrofits in groups of 25-50. Because 2007 emissions regulations are quickly expiring, we're now integrating the hybrid-electric system with the 2010 aftertreatment system to achieve the required NOX reduction," Stark said. 

A hybrid-electric retrofit is a win-win situation for fleets. In addition to saving money by increasing a fleet's overall fuel efficiency, fleet managers who purchase a hybrid-electric system retrofit from FCCC are eligible for federal tax credits up to $4,500 per vehicle under FCCC's approval with the IRS. That amount will likely increase when the new 2010 emissions regulations are enforced. WT

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