Honda Civic Hybrid

The all-new, ninth-generation 2012 Honda Civic Hybrid, using a lithium ion battery for the first time, increases its average EPA fuel economy rating from 41 mpg to 44 mpg. The new model is rated at 44 in both city and highway driving.
The improvement in fuel economy solidifies the Civic Hybrid’s second-place position for fuel economy among cars that don’t plug into the grid. The 44-mpg average moves the Civic slightly closer to the Prius’s 50-mpg level, and edges out the 42-mpg Lexus CT 200h. Honda makes the claim that the Civic Hybrid becomes the most fuel-efficient sedan – meaning it’s not a hatchback – on U.S. roads.
Like other new Civic models – there are now five different versions, including the HF high fuel-efficiency non-hybrid model – the 2012 Civic Hybrid gains a reworked exterior, a redesigned interior and new features.

The Powertrain

The 2012 Civic Hybrid employs the fifth generation hybrid powertrain system that Honda calls Integrated Motor Assist (IMA). It’s a descriptive moniker in that a thin, pancake-type electric motor/generator is “integrated” between the engine and transmission and only “assists” the gasoline engine. This compares to hybrid systems from Ford and Toyota where the electric motor can assist the gas engine plus, propel the vehicle on electric power alone. In certain instances, the Civic Hybrid engine does cut off fuel and the car operates briefly on electric power only, but the engine’s parts still move. Like other hybrid vehicles, the Civic shuts off the engine when the car comes to a stop, and then fires up again when it’s time to go.

In addition to the shift to lithium-ion batteries, the 2012 Civic Hybrid gains a larger gasoline engine, a 1.5-liter four-cylinder in place of a 1.3-liter. Combined gasoline and electric horsepower is unchanged at 110 and torque is up a nominal four pounds-feet, to 127. Yuuji Fujiki, chief engineer for Honda’s IMA hybrid system, explained that the larger displacement allows the engine to run at lower RPMs, which in turn allows for more frequent use of the electric motor and produces a quieter ride.
Fujiki said every aspect of the hybrid system’s design was tweaked for optimal efficiency – such as the motor that increases output from 15 kW to 20 kW, uses more coils and widely spaced magnets, and employs plastic spacers to better manage temperature. The motor provides up to 23 horsepower, a three horsepower gain over the previous motor.

The 20-kW Li-ion battery is more powerful by 5 kW and 30 percent lighter than the previous generation’s nickel-metal hydride battery. The IMA system’s greater power and the battery’s 35 percent increase in efficiency allow the Civic Hybrid to operate more frequently on the electric motor’s power alone in certain low-speed cruising situations.
There’s a side benefit in going lithium: so the next generation of Civic Hybrid owners don’t go postal.
The Civic Hybrid is the only hybrid model for which we’ve seen numerous customer complaints about critical battery failures. Civic Hybrid owners have reported loss of power or outright pack failures, and have not been satisfied with the company’s fixes. The shift to lithium hopefully will put the issue in the rear view mirror.
Completing the IMA system is a continuously variable transmission (CVT). The CVT consists of a drive pulley and driven pulley that are linked by a steel belt, and operates sort of like a 10-speed bicycle. It combines the fuel economy of a high-gear ratio manual transmission, the performance of a low-gear manual with the smooth, stepless shifting of a conventional geared automatic transmission.