Integrated Motor Assist (commonly abbreviated as IMA) is

Honda is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan. Honda has been the world's largest motorcycle manufacturer since 1959, reaching a producti ...

hybrid car A hybrid vehicle is one that uses two or more distinct types of power, such as submarines that use diesel when surfaced and batteries when submerged. Other means to store energy include pressurized fluid in hydraulic hybrids. The basic princip ...

technology, introduced in 1999 on the

Insight Insight is the understanding of a specific cause and effect within a particular context. The term insight can have several related meanings: *a piece of information *the act or result of understanding the inner nature of things or of seeing intu ...

. It is a specific implementation of a parallel hybrid. It uses an

electric motor An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate forc ...

mounted between the

internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal co ...

and transmission to act as a

starter motor A starter (also self-starter, cranking motor, or starter motor) is a device used to rotate (crank) an internal-combustion engine so as to initiate the engine's operation under its own power. Starters can be electric, pneumatic, or hydrauli ...

, engine balancer, and assist

traction motor A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric or hydrogen vehicles, elevators or electric multiple unit. Traction motors are used in electrically powered rail vehicles ( electric multipl ...

Overview

In its first generation, IMA could not power the car on electricity alone, and could only use the motor to assist or start the engine. 2006 Civic Hybrid, however, can activate the electric motor while the vehicle is coasting without turning on the internal combustion engine, though in contrast to

Toyota is a Japanese multinational automotive manufacturer headquartered in Toyota City, Aichi, Japan. It was founded by Kiichiro Toyoda and incorporated on . Toyota is one of the largest automobile manufacturers in the world, producing about 10 ...

's Hybrid Synergy Drive (HSD) or General Motors and

DaimlerChrysler The Mercedes-Benz Group AG (previously named Daimler-Benz, DaimlerChrysler and Daimler) is a German multinational automotive corporation headquartered in Stuttgart, Baden-Württemberg, Germany. It is one of the world's leading car manufactur ...

's Global Hybrid Cooperation, the IMA has a less powerful motor/generator which allows the car to slow or stop its rate of deceleration to a lesser extent; it cannot operate without turning over the engine which is directly coupled to its electric motor.

Regenerative braking

The IMA uses

regenerative braking Regenerative braking is an energy recovery mechanism that slows down a moving vehicle or object by converting its kinetic energy into a form that can be either used immediately or stored until needed. In this mechanism, the electric traction m ...

to capture some of the energy that would otherwise be lost as heat during braking and reuse that energy later to help accelerate the vehicle. This has three effects: it increases the rate of acceleration, reduces the work required of the

engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ...

, and reduces the frequency of brake hardware replacement. The acceleration boost is important as it allows the engine to be scaled down to a smaller but more fuel-efficient variant without rendering the vehicle unacceptably slow or weak. This smaller engine is the primary reason cars equipped with IMA get better highway mileage than their more conventional counterparts.

Starting

Additionally, vehicles equipped with IMA can shut off their engine when the vehicle stops and use the electric motor to rapidly spin it back up when the driver releases the brake pedal (or in the manual transmission variant, when the shifter is placed into gear from neutral). They also have a conventional starter as a backup, making it the only production hybrid system which can operate with its high voltage electric system disabled, using only its engine like a traditional vehicle. However, since the IMA also acts as the vehicle's

alternator An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating magnetic field with a stationary armature.G ...

, eventually the 12 volt accessory battery would require an external charge.

Other names

*ISG: Integrated Starter Generator *ISA: Integrated Starter Alternator *ISAD: Integrated Starter Alternator Damper *CAS: Combined Alternator Starter *CSA: Crankshaft Starter Alternator or Combined Starter Alternator *CISG: Crank-mounted Integrated Starter Generator

List of vehicles using IMA

IMA-equipped Honda Civic Hybrid * Honda J-VX (1997

concept car A concept car (also known as a concept vehicle, show vehicle or prototype) is a car made to showcase new styling and/or new technology. They are often exhibited at motor shows to gauge customer reaction to new and radical designs which may or ...

) *

Honda Insight The is a hybrid electric vehicle that is manufactured and marketed by Honda. Its first generation was a two-door, two passenger liftback (1999–2006) and in its second generation was a four-door, five passenger liftback (2009–2014). In its ...

(1999-2006, 2010-2014) * Honda Dualnote (2001 concept car) *

Honda Fit Hybrid The Honda Fit (Japanese: ホンダ・フィット, Hepburn: ''Honda Fitto'') or Honda Jazz is a small car manufactured and marketed by Honda since 2001 and now in its fourth generation. It has a five-door hatchback body style and is considered ...

(2010-present) * Honda Fit Shuttle Hybrid (2010-present) * Honda Civic Hybrid (2003-2015) * Honda Accord Hybrid (2005-2007) * Honda Freed Hybrid (2008-present) * Honda CR-Z (2010-2016) * Acura ILX Hybrid (2013-2014)

References

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External links

Honda Official "Green Technology - Hybrid"
Automotive technology tradenames Engine technology Honda Hybrid powertrain de: Honda Civic IMA