Technology CIVIC Hybrid
Concept Technology
Honda IMA System/Power Unit
The New Honda IMA System
A world's highest fuel economy of 29.5km/L
Recognized as an Ultra Low-Emissions powerplant

The New Honda IMA System is more efficient than ever.

The i-DSI1 engine's special combustion characteristics result in leaner burning, while VTEC variable valve control technology employed in the VTEC Cylinder Cut-off System contributes substantially to electrical power regeneration (battery charging) during deceleration. Both these features help boost fuel economy.

Motor assist system
The new system employs a higher-output motor, and the IMA nickel metal hydride battery and PCU (Power Control Unit) have been made smaller, lighter, and more efficient, and have been combined with the IPU (Intelligent Power Unit). The resulting package is compact enough to fit into a regular passenger sedan.
New Honda IMA System

Cutaway model the New Honda IMA System IMA's improved efficiency and fuel economy combine with the Honda Multimatic S's continuously variable transmission to achieve astonishing fuel economy of 29.5km/L2-the highest in the world for a 5-seater gasoline-powered production vehicle, even with the automatic transmission. The system delivers high drivability, while exceeding the Japanese government's fuel economy standards for 2010.
Moreover, a lean-burn-compatible adsorption-type NOx catalytic converter and other equipment result in clean-burning performance that has earned the New Honda IMA System recognition by the Japanese government as an Ultra Low-Emissions powerplant.
1 DSI: Dual & Sequential Ignition
2 Fuel consumption in 10-15 mode (Japanese Ministry of Land, Infrastructure and Transport figures)

The 1.3L i-DSI VTEC Cylinder Cut-off System engine:
excellent fuel economy and highly efficient electrical regeneration.

The dual and sequential ignition control system's intensive combustion, along with leaner burning and lightweight construction, create a quantum leap in fuel economy.
The i-DSI engine's combustion characteristics are enhanced by an improved intake port shape that results in a powerful horizontal and vertical swirl. This permits the leaner burning that delivers low fuel consumption. Plateau honing of the cylinder walls creates a silken finish, and the piston skirts are impregnated with low-friction molybdenum sulfide (MoS2) to reduce friction between sliding components to a minimum. Furthermore, in the pursuit of higher fuel economy, each and every part has been lightened.

Engine lightening technologies
*Magnesium alloy head cover
*Plastic intake manifold
*Aluminum connecting pipe
*Plastic idle pulley
*Ultra-compact compressor bracket
VTEC Engine

The valves of three cylinders are left closed during deceleration, resulting in a major improvement in electrical regeneration.
Since excessive engine friction during deceleration can lead to loss of the wheels' rotational energy due to engine braking, the amount of energy that can be regenerated by the motor may be reduced. The New Honda IMA System employs the VTEC System to stop operation of valves in three of the four cylinders, reducing engine friction by 50%, and making possible highly efficient electrical regeneration.

Three cylinders idle
Three cylinders idle
VTEC Cylinder Cut-off System configuration
VTEC Cylinder Cut-off System configuration
Throttle open
Throttle open
Throttle closed
Throttle closed (deceleration)
VTEC Cylinder Cut-off System
When the throttle is open during acceleration or cruising, the valve lift-mode rocker arm and the idle-mode rocker arm are engaged via a synchronizing piston. During deceleration, as soon as the throttle is closed and regeneration begins, the synchro piston is positioned inside the idle-mode rocker arm, disengaging the lift-mode rocker arm so that the valve remains at rest. Since the cylinder is sealed off, pumping losses (resistance caused by engine aspiration) that result in engine friction are reduced, and the wheels' rotational energy is effectively transmitted to the motor. Moreover, cylinder idling can be maintained at engine speeds as low as 1,000rpm, for even greater regenerative efficiency.

Page Top

Honda Worldwide site

Home | Site Map | Site Index | About this Site

Copyright, Honda Motor Co., Ltd. and its subsidiaries and affiliates. All Rights Reserved.