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How Do Hybrids Work?
Hybrid vehicles combine power from a gasoline engine and a battery-powered electric motor. The batteries that power the electric motor, or motors, are charged by the gasoline engine when it's running, and a little bit by energy captured while braking. So, unlike an electric car, you never, ever have to plug it in. Adding the power of an electric motor means you can use a smaller gasoline engine and still get decent performance. Most hybrids also incorporate an "engine shut-off" at idle. So the gasoline engine automatically stops running when you stop at a light, and then instantly restarts when you touch the gas pedal to move again. The result is a significant increase in fuel economy — especially in stop-and-go driving — and a substantial decrease in pollution. Brilliant, or what? We think so.
Different Kinds of Hybrids
A computer decides which source of power to use — and it's quite seamless. You never notice it switching back and forth. Toyota uses a system in which the car is powered by the electric motor in stop-and-go traffic. If you accelerate quickly, which calls for more power, the gas engine will come on, regardless of the speed at which you're driving.
At higher speeds or when you stomp on the gas, the gasoline engine automatically — and instantly — joins with the battery-powered motor, which gives it the juice to pass or merge with highway traffic. Ford's current system is licensed from Toyota, so it works how? Just the same way.
The Accord Hybrid is different. Both the gas engine and the electric motor get you moving from a stop, meaning that the car never operates on electric power alone. The Accord also uses something Honda calls Variable Cylinder Management, shutting down half of the V-6's cylinders at light engine loads to improve mileage and cut pollution. The new Civic Hybrid, however, starts out on its conventional engine, which is then augmented by the battery power when a boost is needed. Once it reaches cruising speed, it runs on the electric motor.
Because a computer takes care of divvying up the work between the gasoline engine and the electric motor, the experience of driving a hybrid is pretty much like any other car. If you didn't have the multi-colored lights on the dashboard telling you what was going on, you wouldn't know there's anything special happening.
What makes the electric motor such a good partner for a gas engine is the fact that electric motors are really, really good at making torque, which is the force that moves you. The Civic Hybrid's electric motor, for example, produces a measly 20 horsepower, but 76 lb.ft. of torque (that's a lot, for such a small motor). That adds substantially to the torque provided by the gasoline engine. Most gasoline engines are as big as they are to give good acceleration, and need only a fraction of their available power while cruising; a hybrid's gas engine can be more efficient — just big enough to keep the car at cruising speed on the highway.
At first, there was just one kind of hybrid, the kind designed to wring the absolute maximum mileage out of each ounce of gasoline. The power of the electric motor was used to augment a little gasoline engine, giving both good gas mileage and reasonable performance. The result was cars like the Toyota Prius, which is rated by the EPA at 60 mpg city, 51 mpg highway and can get up to 650 miles between fill-ups (Note — your actual mileage will suck more than this. Most Prius owners report mileage in the 40's, which is still very good). It gets its best mileage in the city because it spends more of its time operating on battery power alone.
"Mild" Hybrids
Recently, however, car makers then discovered that they could use a hybrid gas-electric powertrain to increase power, at the expense of some of the efficiency. So while getting slightly better mileage, they could better the acceleration of their non-hybrid models. The result was cars like the Lexus GS350H, which can zip from 0-60 in 5.2 seconds, about a half second faster than the V8 GS 430, while getting thirty percent better mileage. The Accord Hybrid falls into this category, too ' its powertrain is rated at 253 horsepower, nine more horsepower than the standard Accord.
We're disappointed with this approach to using hybrid technology. Honda and Toyota seem to be catering to the power mongers, instead of leading the way out of the darkness. Instead of making a more powerful GS for example, we wish Lexus would offer an GS-H. All it would take is a smaller engine, and a little reprogramming of the computer, and you'd have a luxury hybrid that gets great mileage. We'll be right here, waiting.
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