The bus (similar to the one pictured above) has a GVWR of 27,500 pounds, carries up to 38 passengers and uses up to 70% less fuel than a similarly equipped conventional bus — so if the bus got 10 mpg with a conventional engine, it could get 30 mpg using Enova’s hybrid system.
Enova says that independent third party dynamometer testing confirms the vehicle uses up to 70% less fuel than a similarly sized internal combustion engine vehicle. In addition, the tests apparently show that carbon dioxide emissions are reduced by as much as 40%, nitrogen oxide by up to 20% and particulate matter by as much as 30%.
If the bus delivered to Denali is, in fact, the same HC Series hybrid bus listed on the IC Corporation website, then I find that Enova’s above claims are a bit overly rosy in some cases and downright contradictory to IC’s claims in others. After reading through both IC Corporation’s website and Enova’s website, I’m more than a bit confused.
For instance, the IC Corporation brochure about the HC Series hybrid bus (PDF) states that the vehicle has a 25-50% fuel economy improvement when the batteries are constantly charging (charge sustaining), and up to an 80% improvement when the bus is draining the batteries (charge depleting).
Also, another IC Corporation brochure about the HC Series states that the diesel-electric hybrid technology can result in up to a 90% reduction in particulate matter and up to a 60% reduction in NOx emissions. Compare these numbers to Enova’s claims of 30% and 40% reductions, respectively.
An article from Green Car Congress about the Enova/IC hybrid bus clarifies the issue a bit: the fuel economy of these buses is completely dependent on route, driving conditions and engine/power-train configuration.
A route with frequent stops and starts using a bus configured exactly like the one used in the dynamometer test will produce results similar to those claimed by Enova. A bus driven under highway conditions without frequent stops and starts will get much worse fuel economy.
So on a national park tour with many stops and starts, the hybrid bus will probably produce the claimed fuel economy and emissions results. This is excellent news in a place like Denali National Park where diesel prices are incredibly high and the preservation of its pristine beauty is key to its future value.
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Image Credit: IC Corporation