Why are Toyota Prius, Chevy Volt, other hybrids jelly bean shaped?
As sales of hybrid cars continue to rise, one trend among them has emerged above all others. From the popular Toyota Prius and Honda Insight to the struggling Chevy Volt on down the line, these fuel efficient gas=and-electic hybrid cars tend to share the same basic styling motif: they’re jelly bean shaped hatchbacks. The question which car makers have yet to answer is whether it’s for reasons scientific or merely copycattish. The first mainstream-popular hybrid was the Prius, whose egg shape looked unlike that of any existing Toyota model. As competing hybrid models have emerged, they’ve each adopted a similar look. But is that because they’re hoping to tap into the existing popularity of the Prius by vaguely copying its look, or is the jelly bean design part of the secret recipe of fuel efficiency? Chalk this one up to the Department of Befuddlement, as we attempt to solve this mystery.
Toyota may have answered that question when it launched the Camry Hybrid, which looks just like a standard Camry but employs a Prius engine. The result is a car whose gas mileage is improved, but not nearly as much. While the Prius gets 51 miles per gallon, the Camry Hybrid gets a mere 44. That difference may not sound like much until it’s compared to the low 30′s that the standard Camry gets. In other words, when the Prius engine is in a Camry, it only saves a little more than half as much fuel as it does when it’s inside the Prius jelly bean.
Common sense suggests that the more smoothly air can pass over a car while it’s being driven, the less effort the car must exert in order to push through that air. Most traditional cars have several sudden changes in angle from the nearly flat hood to the diagonal windshield to the flat roof and back down to the typically trunk, forcing wind to change directions accordingly while passing over the car. But take away those directional changes in favor of a car design in which the air can pass smoothly, as is the case with the body of the Prius and Volt and so many other hybrids, and it stands to reason that such a body style could get better fuel efficiency simply by working with the wind.
So as the public continues to demand more hybrid cars, are we resigned to a future in which we’ll all be driving egg shaped hatchbacks? After all, even the new hybrid model displayed by Jaguar at the LA Auto Show this year breaks with the auto maker’s distinctive look in favor of a car that looks like a cross between a Jaguar and a Prius. But let’s keep in mind that hybrid technology is still in its infancy, relatively speaking. As battery technology evolves to allow hybrid cars to use only a small fraction of the gasoline they require today, the extra bits of efficiency gained by aerodynamically friendly design may no longer matter. If for instance a decade from now the options are a jelly bean shaped hatchback hybrid which gets 200 MPG, and a more “normal” looking hybrid which gets 180 MPG, then the traditional automobile design as we know it may yet have a future.