When it comes to hybrid cars, Honda has always played second fiddle to Toyota. Their Integrated Motor Assist hybrid system, which used an electric motor mounted on the crankshaft to assist a small gasoline engine, simply couldn’t return the same fuel economy numbers as Toyota’s Hybrid Synergy Drive, which split the gasoline engine and the electric motor. We put 29,000 miles on our long-term 2010 Honda Insight and averaged 42.1 MPG — an impressive figure, but still not as good as the Prius.
Now Honda has a new hybrid system called Earth Dreams, and while the name may be silly, the inner workings are serious: Finally, Honda has a hybrid that rivals (and even bests) Toyota.
Inside Honda’s new hybrid drivetrain
Let’s take a quick look at how the Honda hybrid system works. Fair warning: Honda is using phrases like “dual-motor hybrid” and “e-CVT”, terms often associated with Toyota’s hybrid system. All are misnomers; in fact the Honda system is completely unlike Toyota’s — and in my opinion, it’s way better.
The Honda system consists of a 2-liter gasoline engine (link goes to photo) driving a motor-generator. (Generator would be a more appropriate label; the only “motoring” it does is to start the gasoline engine.) A second motor — the main one — drives the Accord Hybrid’s front wheels. And that’s the key element here: Nearly all of the driving is done by the electric motor. Under lower power demands, the drive motor gets its power from a small battery pack in the trunk; when more juice is demanded, the engine fires up and spins the generator, producing electricity to run the drive motor.
That’s the primary difference between Honda’s new system and Toyota’s: Toyota uses both the gasoline engine and the electric motor as mechanical inputs to drive the wheels. Honda uses the gasoline engine to generate electricity. You can almost think of the Honda’s system as an electric transmission, like that used in diesel locomotives, where a big engine drives a generator that powers motors on the wheels.
The one exception comes when the Accord Hybrid is cruising at steady speeds — a situation where the gasoline engine can do the job more efficiently than the electric motor. When that happens, a clutch connects the engine-generator set to the drive motor, allowing the engine to drive the wheels directly.
(Those of you who are mega-geeks are probably seeing shades of Chevrolet Volt here, and you’re correct: Like the Volt, the Accord Hybrid relies on electricity to drive the wheels, with occaisional direct input from the gasoline engine. Logically, the two are similar, though the Volt’s mechanical arrangement is actually similar to the Toyota Prius. Go figure.)
Enviable MPG numbers…
So what are the advantages of the new system?
Well, the most noticeable one is the super-smooth driving experience. In some hybrids, you can feel the motion of the engine cutting in and out; because the Accord Hybrid relies on the electric motor to do the bulk of the work, the ride is smooth and shift-free, just like a pure electric car.
But the real benefit comes in fuel economy: The Honda Accord Hybrid’s EPA fuel economy estimates are 50 MPG city and 45 MPG highway, which is darn close to the Toyota Prius at 51/48.
Let that sink in: EPA estimates hot on the heels of the Prius. The Prius is a wind-cheating aerodynamic wedge with sheetmetal designed for maximum MPG. The Accord Hybrid is a great big mid-size sedan with acres of back-seat room, one that happens to have Honda’s nifty new hybrid drivetrain under the hood. For comparison, Toyota’s hybrid Camry — which uses a larger gasoline engine than both the Prius and the Accord — is EPA-rated at 43 MPG city/39 MPG highway
…and real-world results
But the amazing thing — the really, truly, stupendously awesome thing — is that the Honda Accord Hybrid really does deliver those numbers. In a week of driving (most of it done with the Accord’s “Econ” mode switched on, though I did take a run on the About.com Top Secret Curvy Test Road), I averaged 44.6 MPG. I’ve driven several hybrid sedans, and so far, the Honda Accord Hybrid is one of only two that has come even close to reaching its EPA fuel economy estimates. (The other was the Toyota Avalon, though again its EPA ratings are lower than the Accord’s — 40/39.) Most hybrid sedans rely on trick aerodynamics, and their fuel economy falls apart in real-world driving.
Louisville Kentucky Honda Dealer, Bob Montgomery Honda, http://www.bobmontgomeryhonda.com