Bookmark and Share

BUS REPORT Spring 2012

Fuel Efficiency Test Results Exceeded Expectations

Thomas Built Buses offers a full line of SCR-equipped school buses

Thomas Built Buses offers a full line of SCR-equipped school buses. Third-party test results show that SCR technology provides at least a seven percent fuel economy advantage on urban routes and a 27 percent advantage on highway routes.

The Thomas Built C2 with selective catalytic reduction (SCR) technology results in a seven to 27 percent fuel economy advantage over the IC CE Series with in-cylinder exhaust gas recirculation (EGR), depending on the route (urban or highway) and transmission mode (Economy or Performance).

How's that for proving our point?

We've always known that the fuel economy of our SCR-equipped buses was better than that of EGR-equipped buses, so we set out to provide measurable, verifiable information to help our customers choose the school buses best suited to their needs and their budgets.

We commissioned an independent, third-party test by Bosch Automotive Proving Grounds in December 2011. The test evaluated a Thomas Built Buses Saf-T-Liner® C2, powered by a Cummins ISB 6.7 liter engine equipped with selective catalytic reduction (SCR) technology, and an IC Bus CE Series, powered by a MaxxForce® DT 7.6 liter engine, equipped with in-cylinder exhaust gas recirculation (EGR) technology. Both buses were EPA 2010 diesel emissions compliant.

The test results demonstrated that the Thomas Built C2 with SCR technology is the more cost-effective choice for budget-conscious customers. And that's particularly important in today's tough economy. A seven to 27 percent fuel economy advantage can add up to an annual operating cost savings of $603 to $1,417, even after factoring in the cost of the diesel exhaust fluid (DEF) required by SCR technology.

But wait. There's more. In addition to budget-sparing fuel economy, SCR-powered engines are more reliable and more dependable because they run at an optimal combustion temperature. SCR-equipped engines regenerate less often than EGR-equipped engines, and fewer regenerations mean you'll be cleaning filters less frequently.

When the first SCR-equipped engines were introduced, the industry's lack of familiarity with DEF caused some concern and some speculation about what a hassle it might be. Wrong! As our customers attest, DEF couldn't be easier to use. It's inexpensive, and it's widely available through distributors and at truck stops across the country. Technicians can simply top off the DEF when they check other engine fluids, so the driver never has to be involved.

Faced with 2010 EPA emission requirements — and an ongoing commitment to maintaining maximum fuel efficiency — we embraced SCR technology. As the results of this recent test so clearly demonstrate, the Saf-T-Liner C2 with SCR technology delivers on that commitment.

"Test results exceeded our expectations," said Tom Hodek, Cummins general manager, Bus Business. "Since day one, we've been confident that our SCR technology offers a fuel economy advantage over alternate emissions reduction technology. This test further defines the advantages of a cleaner, cooler-running SCR engine."

"We've believed for some time that the fuel economy of our buses was better, since we'd taken the SCR technology path," Jed Routh, Thomas Built Buses product planning manager. "This was validated when we heard about actual fuel economy advantages from customers who received the early EPA 2010-compliant Thomas Built buses."

As customers evaluate purchases based on their total cost of ownership of each vehicle, it should be noted that the significant improvement in fuel economy achieved with SCR technology provides a cost advantage to customers, even with the added cost of DEF.

Read our white paper on the test results.