Hybrids are not what they claim!
Posted: Thu Feb 03, 2005 1:39 am
Defroster, Air-Conditioning Put Dent In Hybrids' MileageDetroit Free PressFebruary 3, 2005By Mark PhelanThere's a loophole in how most hybrid gasoline-electric vehicles work, and countless gallons of gasoline are draining out of it. Running the front defroster increases their fuel consumption drastically, as I discovered while driving three of them during Detroit's typically cold winter. Setting the air-conditioning on maximum cool has the same effect, so the problem is not limited to northern regions. None of the automakers admits to knowing how much this increases the hybrids' fuel consumption, but one estimate is that drivers use the defroster or max the air conditioner 10 percent of the time behind the wheel each year. The Ford Escape SUV, Honda Accord and Toyota Prius hybrids all fell far short of the fuel economy figures the companies advertise. Hybrids, which use electric motors to supplement their gasoline engines, have won wide acclaim for the extremely high mileage they achieve in tests by the Environmental Protection Agency. According to the EPA, the Prius, the best-selling hybrid, gets 60 miles per gallon in city driving and 51 m.p.g. on the highway. The Escape is rated at 36 and 31, the Accord 29 and 37. The hybrids fell as much as 40 percent below the EPA mileage figures for combined city and highway driving during my recent test, which covered a mix of Detroit-area roads. "This is clearly a drawback," said Joe Phillippi, principal of AutoTrends Consulting, a New Jersey firm. "The vast majority of the country is affected." The Escape, the largest of the three vehicles, did fairly well, giving me 21.6 m.p.g. The Accord, which Honda promotes both for its fuel efficiency and the added performance of its electric motor, got 20.4 m.p.g. My colleague Tony Swan averaged just over 27 m.p.g. using the defroster only occasionally in the Accord hybrid. His review runs in today's Motor City section. The Prius' fuel economy suffered the most, but particularly cold and slippery weather conditions certainly contributed to its 22.8 m.p.g. A sophisticated feature that shuts the gasoline engine off when it's not needed is one of the key reasons the vehicles score so well with the EPA, but the Escape, Accord and Civic all lose that ability when the front defroster is on. I have tested the Civic before but did not drive it for this evaluation. Nobody really knows how much of the time drivers use the front defroster or max AC. The best guess comes from Ford, which has 30-year-old research that says it's about 10 percent of the time for all drivers in the United States. The Prius can operate its front defroster when the gasoline engine is off, but cold weather keeps the engine from shutting down as often and for as long as it does when the defroster is not engaged. All three vehicles I drove probably got somewhat better fuel economy in my test than if I'd been driving conventional models, but this is just the latest example of hybrids falling short of the hype that surrounds them. Even some very enthusiastic hybrid owners have become frustrated by the cars' failure to delivery fuel economy matching the EPA numbers. "All I want is a damn car that lives up to its promise and that won't make my wife repeatedly tell me I'm a big fool," Civic hybrid owner Pete Blackshaw wrote in his online blog, http://www.hybridbuzz.blogspot.com. Blackshaw of Cincinnati likes his car but writes that he's still nearly 15 m.p.g. below the advertised mileage. "All in all, despite Honda's good intentions, very disappointing." Salespeople I talked to who specialize in hybrids at Detroit-area Ford, Honda and Toyota dealerships were either unaware of or misinformed about how using the defroster and air-conditioning affects fuel economy. "Hybrids are never going to hit the EPA numbers," said Jim Hall, vice president for industry analysis at consultant AutoPacific. "It doesn't surprise me. I think it's a nonissue, though," since most people get worse fuel economy than the EPA mileage posted alongside the price on every car's window sticker. A federal regulation sets standards for how quickly the front defroster must be able to clear ice from a windshield, said Tom Watson, the Ford engineer who developed the Escape hybrid's powertrain. The front defroster uses fluid from the engine to heat air in cold temperatures and runs the air conditioner to clear the windshield on cool, clammy days. Losing the engine's stop-start ability "does make for a reduction in fuel economy," he said. The owners of hybrid cars change their driving habits to increase fuel economy, said Ron Cogan, editor and publisher of the Green Car Journal, a San Luis Obispo, Calif.-based magazine specializing in alternative fueled vehicles. "If your goal in getting a hybrid is maximum fuel economy, you will learn over time the idiosyncrasies of the car and the technology," he said. Another idiosyncrasy affected the Prius I drove. Not only did the engine shut down very infrequently, but it often stopped and started several times during a single stoplight. Under ideal circumstances, the engine shuts down when the car comes to a stop and doesn't start again until you depress the accelerator. Despite that, the Prius' ability to walk and chew gum while other hybrids stumble demonstrates that "Toyota's not just on the cutting edge of this technology, they're sharpening it," said Rich Homan, executive editor of the auto Web site Inside Line. Surprisingly, the Chevrolet Silverado and GMC Sierra so-called mild hybrid pickups, which have been criticized as less technically sophisticated than the other hybrids, can go into engine-shutdown mode with the front defrost or maximum air-conditioning engaged, like the Prius can. "A lot of people put a lot of thought into coming up with our control strategies," said Connie Scarpelli, GM marketing manager for alternate fuel vehicles. "We're very proud of what they accomplished."