PIT Reveals Aero Testing Results

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Trailer skirt fuel savings averaged 6.69%

MONTREAL — The Performance Innovation Transport (PIT) group, a not-for-profit engineering and research enterprise that’s part of FPInnovations, made useful news this week. During its biannual Energotest event at the Transport Canada test track in Blainville, QC, it announced the results of five years of performance evaluations on trailers equipped with side skirts and undercarriage aerodynamic devices. The skirts won.

The test results show that trailers with side skirts consumed an average of 6.69% less fuel than similar vehicles without skirts. Trailers with undercarriage aerodynamic devices consumed 1.43% less fuel on average than similar units without the deflectors.

“The goal of these trials was to identify the real value of each technology so fleet operators can focus their implementation efforts where they get the best value and can more easily justify their capital investment,” said Yves Provencher, director of PIT. “Our controlled test-track fuel efficiency studies accelerate technology implementation and provide the commercial vehicle industry with the information it needs to make sound technology choices.”

For the fuel economy evaluations, PIT tested side skirts from Freight Wing, Laydon Composites, Ridge Corporation, and Transtex Composite. Fuel savings with these devices ranged from 5.2% to 7.45% compared to similar vehicles without skirts.

Trailer undercarriage air deflectors tested by PIT were supplied by AirFlow Deflector, Airman, and SmartTruck. Fuel savings ranged from 0% to 2.2%.

The PIT testing was performed in accordance with SAE J1321 Fuel Consumption Test Procedure – Type II. For each test, unmodified control vehicles and test vehicles had the same general configuration, were coupled to the same trailers for base and test segments, and maintained load weights the same throughout the entire test period. All vehicles were in good working condition and set to manufacturer’s specifications.

Fuel consumption for the tests was measured by weighing portable tanks before and after each trip. The testing consisted of a baseline segment using non-modified vehicles followed by a segment using the control vehicle and test units equipped with the aerodynamic devices. For baseline and final segments, results were presented as the ratio between the average fuel consumed by the test vehicle and the average fuel consumed by the control vehicle. The values for fuel savings reflect the changes resulting from the modification of test vehicles.

The Energotest event was to feature fuel-consumption tests comparing North American and European trucks as well, but the two Volvo tractors imported from Sweden for the duel couldn’t beat bureaucracy. They were held up by Canada Customs, so that testing has yet to be done.

The 2014 Volvo Globetrotter tractors are spec’d with Volvo engines set to the current Euro 5 emissions standard. They’re rated at 460 hp and 1696 lb ft of torque, mated with I-Shift transmissions and 2.57 rear axle ratios.

They’ll go up against two North American Volvo tractors. One is a 2014-model VNL 630 with an EPA 2010 emissions spec on its 425-hp Volvo engine developing 1650 to 2050 lb ft (an Eco Torque version), plus I-Shift direct-drive transmission and a 2.64 rear axle ratio.

The other domestic tractor is a 2009 Volvo VNL 630 with EPA 2007 emissions equipment. It’s a 375-hp/1450-lb-ft Volvo engine with an I-Shift transmission and 3.36 rear axle ratio.

The testing will make the following comparisons: Volvo EPA 2007 vs. Volvo Euro 5; Volvo EPA 2010 vs. Volvo Euro 5; and Volvo EPA 2007 vs. Volvo EPA 2010.

Fuel efficiency will be evaluated using the SAE J1526 Type III fuel consumption tests, which compares the fuel consumption of one component of a combination vehicle to the same component in another combination vehicle, using portable tanks and the gravimetric method. The compared tractors will be switched between the semi-trailers at mid-test.

The tractor-trailer combinations will be optimized to allow the best fuel efficiency, such as the smallest tractor-trailer gap, and matching tractor roof deflector height with trailer height.

The results will be announced at the 2013 American Trucking Associations Management Conference & Exhibition in October.

Based in Montreal, PIT was formed in 2008. It’s an unbiased, neutral testing organization to help manufacturers evaluate and refine prototypes and to assist fleet managers in selecting the best technologies to reduce costs and environmental impact. PIT works in cooperation with the U.S. SmartWay Transport Partnership, Natural Resources Canada, and Environment Canada. The latter has selected PIT as the benchmark facility for testing green transportation technologies.

Membership in PIT has grown to include 26 fleets, 16 municipalities, and four federal and provincial government agencies. Fleets pay an annual membership fee based on fleet size, as little as $35 per vehicle. Manufacturers pay to have their products evaluated.

FPInnovations, the mother ship, is among the world’s largest private, not-for-profit forest research centers, helping the Canadian forest industry develop technologies that promote efficiency and sustainable development. PIT is a logical extension of its work developing technologies for logging trucks.

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Rolf Lockwood is editor emeritus of Today's Trucking and a regular contributor to Trucknews.com.

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