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Examination of alternative transportation part 1: IMA, BAS, and Start-Stop hybrids
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Honda Civic Hybrid Gen 1 Dashboard
Today starts a new weekly feature where we’ll be examining various types of alternative transportation. In part one, we’ll be covering IMA, BAS, and Start-Stop style hybrids, what they are, how they work and what models they come in.
IMA stands for Integrated Motor Assist and is Honda’s proprietary system. It functions in a mentality that the car functions like any conventional vehicle save for when extra power is needed or it’s stopped, at which time the electric system assists or takes over. When extra power is needed, such as when you accelerate sharply, the electric motor kicks in, taking that extra demand off the gasoline engine. At a stop, the gasoline engine disengages, saving you fuel at every stop. You can see a very nice animation of how the system works at http://www.fueleconomy.gov/feg/hybridtech.shtml under the Hybrid setting. Honda is the only manufacturer and their system can be found on the Insight I (1999-2006), the Civic Hybrid (Generation 1 2003-2005, Generation 2 2003-present), the Accord Hybrid (2005-2007) and the Insight II (2010-Present)
Like every hybrid, there are advantages and disadvantages. The price difference between a conventional gasoline model and an IMA Hybrid equipped model is less then the price difference between other hybrid systems while still offering palpable mileage boosts beyond their conventional equivalent. They’re also very well suited to expressway driving; many owners report getting as much as 20 MPG beyond the EPA estimated MPG with relative ease. On the flip side, their performance in city and on congested roads is far less admirable, every time you take your foot off the brake the gasoline combustion engine comes on to the frustration of many owners who are attempting to be miserly with their fuel.
Bottom line, if you’re on a budget and want to save fuel, look at IMA, especially if a large portion of your commute is at higher speeds.
BAS stands for Belt Alternator Start and is one of two hybrid systems that GM sells under their hybrid Green Line logo. While on paper BAS functions much like IMA, by being a gasoline vehicle with electric assist, in reality the so called electric assist is so minimal as to be nearly invisible to most drivers. http://www.fueleconomy.gov/feg/hybridtech.shtml you should look more at the Stop/Start animations to get a feel for how the hybrid functions. BAS is available on Saturn Aura Green Line (2007-2009), the Saturn Vue Green Line (2007-2009), and the Chevy Malibu Hybrid (2008-2009).
BAS is the cheapest hybrid system available when compared to their conventional gasoline equivalents, I’m sorry to say that’s about their only advantage. They offer meager fuel economy improvement against their conventional counterparts and early models suffered from problems resulting in a very high percentage of owners having to have components replaced due to catastrophic failures in their drivetrains and electric systems.
Bottom line, if you’re taking a serious look at BAS hybrid systems due to their price, consider a smaller and more efficient gasoline vehicle instead such as the Chevy Aveo, the Honda Fit, the Toyota Yaris, or the Ford Focus.
Start-Stop hybrids, also known as Microhybrids are a relatively common technology in countries in Europe and Japan. Sadly, there is only one model with the technology in the US, and that’s the Chevy Silverado Hybrid (2004-Present). Under the flash animation http://www.fueleconomy.gov/feg/hybridtech.shtml it falls under the Stop/Start Hybrid, providing no motive power but allows the combustion engine to disengage at a stop.
Start-Stop hybrids are useful on work sites, as the electric battery provides power for tools and recharging batteries on the fly and anything else that you’d otherwise need a higher powered outlet to run or recharge, like a blender.
Start-Stop Microhybrids can be found internationally on various BMW’s, VW’s, Toyota’s, the SMART fortwo, and even on Tata Motors Tata Ace. None of the aforementioned companies believe that bringing their technology to America would be a profitable decision.
Bottom line, Start-Stop hybrids offer a very modest fee for very little improvement in fuel economy, but it is an improvement and on depending on its duty life, that extra power can be of enormous use. However, for the average driver, the technology simply isn’t worth it.
Next week we’ll look at "Full Hybrids", including Toyota’s HSD, Ford Hybrid systems and GM’s Two-mode Hybrids.
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