A Beltless Engine

Scott Benjamin

The 2010 Toyota Prius is shown on display at the North American International Auto Show in Detroit, Mich. (AP Photo/Paul Sancya)

Have you ever lost an accessory drive belt when you're out on the road? I have -- and it's usually a bad situation. Even car owners who consider themselves to be well-prepared by carrying a wide variety of hand tools, heavy-duty rope, straps, tape, assorted lengths and sizes of tubing, electrical wire, spare spark plugs and so on (yes, I was a Boy Scout), typically don't carry spare engine belts. However, it's not a bad idea to do so. Second, unless you're paying close attention to the instrument panel, there's a good possibility that you might not even notice anything is wrong -- that is, until it's too late. And, of course, there's always this angle, too: If you're going to be stranded on the side of the road, chances are that you'll be in a desolate (or dangerous) part of town or perhaps out in the middle of nowhere. You know, because Murphy's Law plays an important role in this whole situation as well.

Soon, however, there's going to be one group of new car owners on the road who won't have to worry about that particular kind of maintenance. The 2010Toyota Prius is going to be equipped with a beltless engine. According to Toyota's press release, "The 1.8-liter Prius engine is the first Toyota power plant that requires no belts under the hood for better fuel economy and less potential maintenance." That's right, no belts. And that means no more chirping or squealing belts under the hood when you start your car in the morning. No more belt tensioners to adjust. No more belts to slip off of various pulleys and the expensive component (or engine) repairs that are sure to follow. And increased fuel economy, too? Personally, I think this is a good development.

All of the accessories that are normally powered by the engine (via a series of belts or a single serpentine belt, in some cases) are now powered by electric motors. That means that the power steering pump, air conditioner, alternator and even the water pump all are electrically driven. In addition to the reduced maintenance and increased fuel economy, this means that any (or all) of the accessories can remain functional -- even when the engine isn't running.

It's just a guess, but if this design proves to be successful, I would expect that this beltless engine idea just might gain some momentum in the marketplace. I mean, better fuel economy, less maintenance and quieter operation? What's not to like about that?

More related stuff: How Car Engines Work How Electric Motors Work HowStuffWorks - Auto Fuel Economy Channel 2010 Toyota Prius Review and Prices