Smarter hybrid cars on the way
Glaskowsky explains a new kind of hybrid car we're likely to see in the next few years.
A friend of mine sent me a link to a story at gizmag.com (here) that quotes another site as saying that Porsche is planning to offer a hybrid-power version of its forthcoming Panamera sedan. (I couldn't find the story on the original site, so I can't offer a link to it.)
The story claims this might be the fastest hybrid car in the world when it debuts in 2011, but that's purely hypothetical. By that time, there will likely be a lot of very fast hybrids. In fact, I suspect that most cars will be sold as hybrids by 2015 or so. Once the necessary technology is developed, hybrids will have substantial economy, reliability, and performance advantages over cars powered solely by gasoline or diesel fuel.
The new technology goes by various names, each with its own associated design details-- "integrated starter alternator" (ISA) is one name that was commonly used some years ago when this approach was first considered (as in the Dec. 2002 EE Times story here). "Integrated motor assist" is what Honda is calling its version, and GM, DaimlerChrysler, and BMW have at least two names for the approach they are pursuing together: "Global Hybrid Cooperation" or (GM's preference) "two-mode hybrid." The latter team has also developed a new kind of automatic transmission for the system.
Basically, all of these boil down to the same thing: integrating an electric motor right into the transmission. The classic ISA design uses a large "pancake" electric motor between the engine and the transmission; the other variants put the motor (or motors) in the same general area.
All of these designs can operate in multiple different modes:
- Using the electric motor to start the gas engine (thus replacing the conventional separate starter motor)
- Running the motor as a generator to charge the batteries (thus replacing the conventional alternator)
- Using the motor as an electrical braking system (also known as regenerative braking)
- Using the electric motor alone to drive the wheels (pure electric car mode; the size of the motor determines acceleration and speed limits in this mode)
- Using the gas engine alone
- Using the engine and motor together for better acceleration and greater smoothness
- And (when the ISA design is coupled to a manual transmission) the electric motor can also be used to assist shifting by slowing down or speeding up the gas engine and synchronizing the gears before the clutch is reengaged
So for the cost of a largish electric motor (partially offset by the elimination of a starter and alternator), you get a car that's more efficient (because of the usual hybrid advantages), more reliable (less wear and tear on gears), and potentially faster (if the electric motor is powerful enough).