Accord Hybrid’s Unique Powertrain Delivers High Mileage, So-So Drivability

COLUMBUS, OH – What’s so special about the new Honda Accord Hybrid?

Two things: Its groundbreaking 50 mpg (4.7 L/100 km) EPA city rating for starters, and the fact that this new-generation model has no transmission.

Honda press materials speak of the existence of an E-CVT, or electric-coupled, continuously variable transmission onboard the car. But as with the Toyota Prius or Ford C-Max that’s really just a euphemism for a computer-controlled setup that uses two electric motors in tandem to provide step-less, wide-ratio range transmission of torque to the drive wheels, similar to what a conventional CVT would do.

There is no torque converter, pulley, belt or other mechanical connection between the generator motor and electric traction motor.

The ’14 Accord Hybrid, which is technically the second U.S. model to employ Honda’s new Earth Dreams Technology powertrain in place of the last-generation IMA (Integrated Motor Assist) system, is actually a lot closer to an electric vehicle in the way it works than a conventional hybrid.

The powertrain consists of a generator motor that keeps the lithium-ion battery charged and funnels electricity to a traction motor positioned up front to drive the wheels. A 2.0L Atkinson-cycle, DOHC 4-cyl. gasoline engine with i-VTEC variable valve timing completes the package.

Honda says the Earth Dreams system offers three modes of operation, electric-only, hybrid and engine drive.

If piloted extremely conservatively, it is possible to keep the Accord Hybrid in electric-only mode, moving solely on its battery power for a short distance, and at speeds up to 60 mph (97 km/h), Honda engineers estimate. There’s a dash-mounted EV button that allows the driver to lock the powertrain in pure-electric mode, keeping the internal-combustion engine shut down until the battery requires recharging.

Otherwise, it’s only when available stored energy becomes depleted or the car reaches highway speeds that the car kicks on its gasoline engine.

In hybrid mode, the IC engine acts like a generator to create electricity to supply the traction motor, working in a fashion similar to the plug-in Chevrolet Volt.

At highway cruising speeds, the Accord Hybrid slips into engine mode and, unlike the C-Max and Prius, decouples its electric powertrain, allowing the 141-hp 2.0L powerplant to drive the front axle directly via a single lockup gear that performs the same function as an overdrive sixth speed in a conventional transmission.

It’s a unique concept that, thanks to some sophisticated software, manages that highway-speed transition from electric to gasoline power nearly seamlessly.

So why not just follow the Volt formula instead? Battery size, weight and cost.

Unlike the Volt, which packs a 400-lb. (181-kg) 16.5 kWh Li-ion battery into its center tunnel, the Accord Hybrid uses only a 1.3-kWh unit that spans the width of the car and is a little more than a foot (30 cm) deep.

Even compared with the battery of the Accord Plug-In, which was the first car to employ the Earth Dreams powertrain but can be recharged for 13 miles (21 km) of electric-only range, the Accord Hybrid’s pack is about one-fifth the size and eats up a more modest 3.1 cu.-ft. (88 L) of trunk space.

Honda says the setup that allows the engine to drive the front wheels directly also is more efficient at highway speeds, because there’s less power lost than if the gasoline powerplant was used to create electricity to drive the traction motor.

Mileage is impressive, leading the competition with its city rating and registering a solid 45 mpg on the highway and 47 mpg (5.0 L/100 km) combined. What’s more, the car actually delivers on its promise. In 36 miles (58 km) of mixed driving in and around the Ohio State University campus here, the Accord Hybrid checks in at spot-on 47.1 mpg.

In a short, 5-mile (8-km) city loop to see how much mileage could be wrung out of the sedan, we hit 56.0 mpg (4.2 L/100 km), while launching conservatively but adhering closely to posted speed limits. Other drivers here employing hypermiling manage miles-per-gallon numbers in the 60s and 70s.

One of the car’s strong points is its regenerative braking, a key focus for Honda developers. Brakes perform linearly, with none of the clutch and grab often associated with hybrids and EVs.

Other changes from the standard Accord are minimal. The Hybrid gets an aluminum hood and all-aluminum subframe, rather than the aluminum-steel component found in the conventionally powered car. Inside, the instrumentation includes some additional mileage- and battery-tracking gauges, but otherwise it’s pretty much standard Accord.

Shortfalls of the U.S.-built Accord Hybrid include its busy city-speed operation and high starting price.

Even though there’s no actual CVT, the electric-motor setup behaves just like one, meaning there’s too much of that rubber-band effect as the two motors adjust ratios to match inputs from the accelerator. That makes the Accord Hybrid nowhere nearly as smooth an operator as the Volt.

The electric motor produces excessive noise and generates a rather unpleasant whine as the car works up to speed.

But these are common traits among hybrids on the market, and that may be a tradeoff environmentally conscious buyers are willing to live with in exchange for 50 mpg.

The cost may be a more difficult hurdle for more casual shoppers. With prices starting at $29,155 for the base Hybrid trim and escalating to $31,905 for the midgrade EX-L and $34,905 for the top-of-the-line Touring, the Accord checks in above its key rivals.

Honda officials say their hybrid packs in more standard equipment, and they’re confident car buyers comparing prices will recognize its value. But the entry price marks a significant jump from a conventional Accord (the premium is $3,600 on EX-L models), and it may be asking a lot of more value-minded Internet shoppers to see past that cost premium.

Honda officials are reluctant to forecast volumes in the U.S., though they say sales in more hybrid-friendly Japan topped 6,000 units in the car’s first couple months of availability. Unlike the Accord Plug-In, which is available only in California and New York and has sold 349 units so far this year in the U.S., the Hybrid model is available nationwide beginning this month.

In the end, the Accord Hybrid likely will appeal to a limited set of Honda buyers who are looking for the highest mileage they can get and don’t mind paying for it.

Those with a tighter budget would do well to stick with a smoother-driving 4-cyl. Accord. Its fuel economy may not be as eye-popping as the Hybrid model, but starting at $21,995, it can be had for thousands of dollars less and is fun to drive, earning a spot on the 2013 Ward’s 10 Best Engines list.

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