2014 Honda Accord Hybrid Has No Transmission: How It Works

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2014 Honda Accord Hybrid

2014 Honda Accord Hybrid

The 2014 Honda Accord Hybrid has no transmission.

To be more precise, there's nothing in a form we'd normally recognize as a transmission—no conventional automatic transmission, no automated dual-clutch system, no belt-and-pulley continuously variable transmission (CVT) either. There's no torque converter, either—not even a drive clutch to slip the engine from a standing start.

Enough about what the Accord Hybrid doesn't have; here's what it does have: In addition to a lean four-cylinder engine, there are twin electric motors (each purposed and configured differently), a compact 1.3-kWh battery pack, and an electronically controlled clutch pack. 

Not related to IMA; this one's a 'full hybrid'

The hybrid system in the 2014 Honda Accord Hybrid is an all-new one—completely different than the familiar Integrated Motor Assist (IMA) setup that's been used in a wide range of Honda (and Acura) products over the years. This vehicle (and the Accord Plug-In Hybrid) have a system called Intelligent Multi-Mode Drive (i-MMD).

2014 Honda Accord Hybrid motor system

2014 Honda Accord Hybrid motor system

Core to the system is that couplet of electric motors (we call it that because of how neatly they're packaged and nested together), of which one is always connected to the wheels. One of them drives the vehicle—the propulsion motor—while the other stays connected to the engine and functions primarily as a generator.

The gasoline engine in the 2014 Honda Accord Hybrid is a 2.0-liter in-line four, with i-VTEC intelligent valve timing and lift and an Atkinson-cycle. It makes a peak 141 horsepower and 122 pound-feet of torque, and it's not mechanically connected to the drive wheels under most driving conditions.

But in steady-speed highway cruising a multi-plate wet clutch and controller system connect it—essentially in a direct-drive configuration that's about equivalent to the top gear in conventional transmissions.

This unique arrangement essentially creates four different drive modes: Electric Vehicle (EV). Hybrid Vehicle (HV), Engine mode, and Regeneration mode.

2014 Honda Accord Hybrid i-MMD configuration

2014 Honda Accord Hybrid i-MMD configuration

2014 Honda Accord Hybrid operating modes

2014 Honda Accord Hybrid operating modes

Four drive modes--and only one with the gasoline engine connected to the wheels

The majority of the time—during lower-speed driving, deceleration, and most acceleration, the gasoline engine is decoupled from the drive wheels, and you'll be driving the Accord Hybrid with the gasoline engine either off, or at a wide range of possible revs that don't directly correspond to speed.

Here, the gasoline engine is directly powering the generator—which, in turn is sending power directly over to the propulsion motor, with the 1.3-kWh battery also kept charged by the generator and by deceleration and braking.

Honda confusingly calls this an eCVT, which we think implies that there's an actual continuously variable transmission (CVT), as in the most popular configuration (about 80 percent) of the current-generation Honda Accord models.

'Engine mode' for highway cruising

However, the only time the gasoline engine is directly connected to the wheels is in high-speed cruising, where the engine is kept in its most economical range—Honda engineers call it 'engine mode' and the propulsion motor provides some boost when needed.

In the Accord Hybrid, the 1.3-kWh lithium-ion battery is stowed just below the back seat—preventing the rear seatbacks from slipping forward but not affecting rear passenger space.

2014 Honda Accord Hybrid battery pack

2014 Honda Accord Hybrid battery pack

The battery pack and controller hardware together weigh about 155 pounds—coincidentally, about the weight of a typical automatic transmission.

The Accord Hybrid weighs 3,550 pounds in its base form, or up to 3,602 pounds in top Touring trim; that's within a hundred pounds of major rivals like the Toyota Camry Hybrid, Ford Fusion Hybrid, Hyundai Sonata Hybrid, or Kia Optima Hybrid.

The Honda Accord Hybrid weighs a bit more than the standard Accord, but it gets amplitude-reactive dampers to help ward away ride harshness, as well as an electric servo braking system to smooth the last 5 mph of braking—which can be a bit uneven in some hybrids.

How will the 2014 Honda Accord Hybrid perform? Visit our drive of the closely related Honda Accord Plug-In Hybrid first, then stay tuned tomorrow for full driving impressions of the Accord Hybrid.

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