Honda’s new Civic SE Executive 4 door saloon, powered by IMA with its highly advanced petrol-electric system delivering exceptional fuel economy, heralds a new era in high efficiency transportation.
Building on experience with the first-to-market Insight, this new Civic model from Honda represents the first application of such technology on an established mainstream platform. Already over 15,000 units have been sold in Japan and the USA and now European customers can enjoy the benefits of a combined fuel consumption of almost 58 mpg (4.9 l/100 km), CO2 of 116 g/km and emissions that better the Euro IV standard.
In Britain, the Civic IMA will be sold (from May 1st 2003) as an integrated part of the Civic range. It will be sold with a high level of equipment and refinement, and will offer increased operating efficiency and reduced personal tax liability for company car drivers without any disadvantages in terms of service or maintenance requirements when compared with other petrol or diesel C-sector cars.
Based on the Civic 4 door saloon, the Civic IMA uses a 1.3 litre i-DSI petrol engine coupled with a thin and lightweight electric motor for enhanced fuel economy and added power when accelerating. The electric motor acts as a generator during deceleration and braking, automatically recharging the car’s battery pack. The end result is a highly economical, roomy and comfortable 5-passenger saloon that retains all of the Civic family’s class-leading safety, performance, refined handling characteristics, reliability and legendary build quality
Further contributing to economy are aerodynamic enhancements that include a refined front bumper, a boot spoiler and under-body covers.
The IMA hybrid power unit of Honda’s Insight captured the International Engine of the Year award in 2000 for its innovative combination of an efficient petrol engine and an electric motor positioned between engine and transmission to provide a simple solution to the seemingly incompatible task of combining both efficiency and performance.
The Second Generation IMA system launched in the 2003 Civic 4 door ushers in a new era of high efficiency transportation, applying proven IMA technology to a mass-produced vehicle on an existing platform. It builds on the Insight’s technological concepts, but it does so using a significantly different mechanical system packaged in a conventional body design.
The principles of IMA
Honda’s patented IMA concept is grounded in simplicity - use a highly efficient gasoline engine and supplement the performance with an electric motor. Also referred to as a ‘hybrid’ system because it uses two power sources, IMA allows the use a smaller gasoline engine without any significant loss in performance. The 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 electric motor positioned between the engine and transmission assists the engine when accelerating and recaptures energy when braking or decelerating (regenerative braking), allowing it to operate independently without the need for an outside power source. When the Civic Hybrid is coasting or its brakes are applied when the engine is in gear, its electric-assist motor becomes a generator, converting forward momentum (kinetic energy) into electrical energy, instead of wasting it as heat during conventional braking. Energy is stored in the system's Nickel Metal Hydride (NiMH) battery pack located behind the rear seat in the boot. If the charge state of the IMA battery is low, the motor generator will also recharge while the Civic Hybrid is cruising.
In place of the 1.0 litre 3-cylinder engine of the Insight, the 2003 Civic IMA uses a 1.3 litre 4-cylinder i-DSI gasoline engine similar to that used in the new Honda Jazz; it also features a more powerful electric motor, while numerous electrical components have been combined, lightened and reduced in size.
With its low fuel consumption and high torque at low and medium speed ranges, i-DSI technology is ideal for an IMA application. Its compact dimensions mean that the 1.3 litre engine is shorter than the normal Civic petrol engine, which allows the electric motor/generator to be positioned between the engine and transmission within the same amount of engine bay space. From front of engine bay to back, the Civic IIMA powertrain measures 575 mm, slightly narrower than a conventional Civic. The IMA power unit will be teamed with a 5-speed speed manual transmission for the UK.
The Civic’s second generation IMA system delivers increased performance and provides enhanced packaging flexibility when compared to that of the Honda Insight. Additionally, the IMA batteries and related components utilise minimal cargo space in the trunk, leaving room for items such as two large pieces of luggage or a baby buggy.
The ultra-thin DC brushless motor delivers the world's highest output density for an electric motor, achieving 30 per cent more torque than that used in the Insight – without any increase in size. This peaks at a particularly useful 1000 rpm (62 Nm).
Other significant enhancements of the IMA system include:
New winding methods for the motor resulting in greater wire density
New Intelligent Power Unit (IPU) combines the Power Control Unit (PCU) and the battery pack, which results in a 42 per cent reduction in volume
Within the IPU the combination of the inverter and pre-driver results in a 28 per cent weight saving and a 39 per cent volume saving
New high-density silicone wafers in the inverter contributing to 25 per cent less heat loss
A new cooling system which combines two fans into one while consuming 85 per cent less energy to cool both the battery and the PCU, resulting in a 32 per cent weight reduction and a 20 per cent volume reduction
A battery module with reduced resistance and reduced energy losses, which improves output density by 23 per cent. More welding points between the pole plates and current collector plates contribute to this improvement
A battery box reduced in volume by 30 per cent and in weight by 6 per cent
Engine specification comparisons
2003 Civic 4dr IMA
2002 Civic 5dr
1.6i VTEC petrol
2002 Civic 5dr 1.7 diesel
No. of cylinders
Power PS @rpm
90 @ 5700
110 / 5600
100 / 4400
Torque Nm @ rpm
159 / 1000
152 / 4300
220 / 1800
Fuel economy EU Combined (mpg)
CO2 emissions (gm/km)
VTEC controlled cylinder idling system
The aim of regenerative braking is to reclaim as much energy as possible during deceleration, and the engine therefore needs to provide as little resistance as possible. In a traditional engine, the pumping action of the cylinders will actually provide a moderate amount of resistance, or ‘engine braking’. The Civic IMA therefore features a cylinder idling system which effectively reduces engine drag by closing the intake and exhaust valves on up to three of the four cylinders enabling the pistons to move more freely within the cylinders, thus allowing the generator to provide maximum resistance (instead of the engine) and, consequently, to produce more electricity.
The system uses Honda's VTEC (Variable Valve Timing and Lift Electronic Control) technology to close the intake and exhaust valves on up to 3 of the 4 cylinders at engine speeds as low as 1000 rpm.
Automatic Idle Stop
The petrol engine is automatically turned off during complete stops under most circumstances and uses the electric motor to re-start the engine. The Idle Stop feature is not activated during the first few minutes of engine startup or if the automatic climate control system is being used in air conditioning mode and "Economy Mode" is not selected.
Electronic Instrument Display
Since the Civic IMA uses a unique powertrain, the vehicle's gauges and readouts are unique, too. The digital and analogue electronic instrument display features the traditional set of meters along with comprehensive IMA readouts. When the ignition is turned off, the panels appear blank (black). When the ignition is turned on, the numbers are backlit with high-tech blue and red needles against a black background. A dimmer switch is located just to the right of the odometer and the gauges automatically adjust to night-time mode when the lights are turned on.
The electronic instrument display allows the driver to monitor more than 23 vehicle systems with the following instrument readouts:
Speedometer (analogue) with large numbers
Tachometer (analogue) with large numbers
Shift Light: Indicates the correct time to shift for maximum economy
Auto Stop: When the engine turns off automatically using the Idle Stop feature, this light turns on
Miscellaneous Indicator Lights: Oil pressure, low fuel, SRS, EPS, IMA, parking brake and battery
Odometer with Dual Trip Meters (digital): Displays vehicle mileage and has two trip meters, marked A and B. Mileage display controlled by pushing the Select/Reset button located under the speedometer
Fuel Economy Estimator - (digital): Shows numerical estimate of miles per gallon for either trip A or trip B mileage
Instantaneous Fuel Economy Meter: Bar graph meter (with numbers) shows an estimate of real time fuel economy
IMA Charge/Assist Meters (LCD): Indicates when the IMA battery is being charged or when it is providing electrical power assist
IMA Battery Charge Level (LCD): Indicates how much power the battery has stored
Fuel Gauge (LCD)
Engine Temperature (LCD)