IMA Basics
The concept for the 2003 Civic Hybrid's powertrain is grounded
in
simplicity - use a highly efficient gasoline engine and
supplement
the performance with an electric motor. On the surface, the
system
may appear complex, but the Civic Hybrid powertrain provides a
simple
solution for the seemingly incompatible task of combining both
efficiency and performance. Honda's solution is its patented
Integrated Motor Assist (IMA) system, which is also referred to as
a
"hybrid" system because it uses two power sources - gasoline
and
electricity. This system allows the Civic Hybrid to use a smaller
gasoline engine (compared to other Civics) without any
significant
loss of performance.
The Civic Hybrid IMA system is comprised of three main components: the gasoline engine, the electric motor, and an energy storage device. The electric motor is positioned between the engine and transmission. The electric motor assists the engine when accelerating and recaptures energy when braking or decelerating (regenerative braking). Most of the vehicle's propulsion comes from the gasoline engine with the electric motor providing assist as needed. The IMA system is especially effective when you consider that acceleration requires a significant amount of power and energy (requiring a larger displacement engine at the expense of overall fuel economy), but the extra displacement is not necessary while driving at a constant speed on a level road (where vehicles spend the majority of their time). The IMA system effectively manages this challenging aspect of vehicle propulsion. The IMA system combines the strengths of the gasoline and electric systems to increase overall efficiency. The electric motor enhances the power provided by the gasoline engine. Reciprocally, the gasoline engine enables the electric motor to operate independently without the need for an outside power source.
Overview
The 2003 Civic Hybrid uses a new generation of Honda's IMA
technology, building on the one that originally debuted on the
1.0-liter 3-cylinder 2000 Honda Insight. The new Civic Hybrid has
a
larger 1.3-liter 4-cylinder gasoline engine featuring several
technology breakthroughs and a more powerful electric motor.
Also,
numerous electrical system components have been combined,
lightened
and reduced in size.
The Civic Hybrid's IMA system occupies the same width dimensions in the engine bay as the conventional Civic sedan even with the increased componentry from the IMA system. The 1.3-liter inline 4-cylinder i-DSI engine is shorter than the 1.7-liter inline 4-cylinder engine used in the Civic sedan, which allows room for the 10 kilowatt electric motor/generator to be positioned between the engine and transmission within the same amount of engine bay space. Both transversely mounted powertrains measure the same length, 35.8 inches (883mm). Widthwise from the front of the engine bay to the back, the Civic Hybrid powertrain measures 25.8 inches (575 mm), which is slightly narrower than a conventional Civic.
Powertrain Highlights:
- Second generation Integrated Motor Assist (IMA) hybrid system uses a 1.3-liter 4-cylinder gasoline engine with Dual & Sequential Ignition (i-DSI) and is assisted by a powerful electric motor with a compact Intelligent Power Unit (IPU).
- New i-DSI lean burn combustion technology uses two spark plugs per cylinder and maximizes combustion for economy and power.
- New cylinder idling system adapts Honda's VTEC variable valve control system to significantly increase the amount of kinetic energy recovered during deceleration. The system reduces engine resistance, greatly improving the vehicle's regenerative efficiency.
- Improved ultra-thin DC brushless motor delivers the world's highest output density for an electric motor and achieves 30 percent more torque than the previous model - without a size increase.
- New Intelligent Power Unit (IPU) combines the Power Control Unit (PCU) and the battery pack, which results in a 42 percent reduction in volume (compared to the Insight's IPU) for improved packaging flexibility and reduced weight.
- Choice of Continuously Variable Transmission (CVT) automatic transmission or manual transmission.
- Creeping Aid System (on CVT models) minimizes the car from rolling backwards from a stop on steep hills.
- Achieves ULEV emission standards. (A SULEV version will be available in California in January 2003.)