Honda has developed multiple hybrid systems to improve fuel efficiency and performance across its vehicle lineup. The evolution began with the
Integrated Motor Assist (IMA) system in 1999, which used a single electric motor to support the engine, offering
mild hybrid functionality. In 2013, Honda introduced the Intelligent Dual-Clutch Drive (i-DCD) system, which added a dual-clutch transmission and enabled full electric drive at low speeds. The same year, the Intelligent Multi-Mode Drive (i-MMD) system was launched, featuring a two-motor setup that seamlessly switches between EV drive, hybrid drive, and engine drive for optimal efficiency. For high-performance applications, Honda developed the Sport Hybrid SH-AWD (Super Handling All-Wheel Drive) system, which combines a V6 engine with three electric motors to deliver both all-wheel drive and
torque vectoring capabilities.
Integrated Motor Assist The Integrated Motor Assist, or IMA as it is commonly known, is Honda's hybrid car technology that uses a gasoline-electric drive system developed to achieve higher fuel economy and low exhaust emissions without compromising engine efficiency. The IMA system uses the engine as the main power source and an electric motor as an assisting power during acceleration. It was first designed for the Honda Insight in 1999, which combined the electric motor with a smaller displacement VTEC engine and a lightweight aluminium body with improved aerodynamics. Low
emissions target was realized when the car achieved the EU2000. In 2001, the Honda Insight Integrated Motor Assist system was declared "Best New Technology" by the Automobile Journalists Association of Canada (AJAC). The development of the IMA system is a result of optimizing the various technologies that Honda has built over the years, including the lean-burn combustion, low-emission engines, variable valve timing, high-efficiency electric motors, regenerative braking, nickel-metal hydride (Ni-MH) battery technology and the microprocessor control. The target of this integrated system was to meet improvements in several areas: •
Recovery of deceleration energy With the IMA system, the amount of energy regeneration during deceleration is optimized and friction is reduced. The recovered energy is used to supplement the engine's output during acceleration. •
Reduction of energy displacement The IMA supports the engine during a low rpm normal driving range by utilizing the electric motor to generate a high-torque performance. When the gasoline engine enters a higher rpm range, the electric motor ceases and power output is supplied by the VTEC engine. The assistance from the electric motor reduces the work of the gasoline engine, allowing the engine to be downscaled. This results in better mileage and reduces fuel consumption. •
Idle stop system The power from the electric motor is generated and conserved when the vehicle moves forward. When brakes are applied, the IMA system shuts off the engine and conserved power from the electric motor is utilized. This minimizes vibration of the car body and saves fuel when the engine is idling. When the brakes are released, the electric motor will restart the engine. The i‑DCD system was offered primarily in Japan and introduced to Malaysia in 2017, making these the only markets to receive mass-market i‑DCD-equipped models like the Jazz Hybrid, City Hybrid, and HR-V Hybrid. However, the compact DCT has exhibited overheating and clutch problems under heavy stop-and-go conditions: the actuator (DOT‑4) fluid degrades from heat and moisture, leading to clutch slippage, fluid leaks, and transmission overheat warnings, issues preventable with regular fluid changes every ~20,000 km and transmission oil replacement every ~30-40,000 km. Moreover, in Japan, about 81,000 Fit and Vezel Hybrids produced from July 2013 to February 2014 were recalled due to software glitches in the DCT control unit that caused gear engagement failures, requiring software reflashes and, in some cases, component replacement to resolve start-up delays or non-engagement problems.
System Architecture •
Hybrid system configuration: • 1.5 L Atkinson-cycle
LEB-series DOHC i‑VTEC petrol engine • 7-speed dual‑clutch transmission with built-in electric motor • Lithium-ion battery and Intelligent Power Unit (IPU) • Electric servo-brake and fully electric compressor
Operation modes •
EV Drive: pure electric from stand-still •
Hybrid Drive: engine and motor propel via DCT •
Engine Drive: engine directly drives wheels
Among the Honda car models that are using i-DCD •
Honda Fit/ Jazz Hybrid (Japan/ Malaysia, 2013-2020) •
Honda Grace/ City Hybrid (Japan/ Malaysia, 2013-2020) •
Honda Vezel/ HR‑V Hybrid (Japan/ Malaysia, 2013-2022) •
Honda Fit Shuttle Hybrid (Japan, 2015-2022) •
Honda Freed Hybrid (Japan, 2016-2024)
Sport Hybrid SH‑AWD (Super Handling All‑Wheel Drive) Sport Hybrid
SH‑AWD is Honda's advanced torque-vectoring, three-motor AWD
series-parallel hybrid system that debuted in the 2014
fifth-generation Legend and 2014
Acura RLX. It combines a petrol engine with three electric motors: one at the front and two at the rear, for superior traction, handling, and performance.
System Architecture •
Three‑motor layout: A front-mounted electric motor and two independently controlled rear motors (Twin Motor Unit, or TMU) are powered by a lithium-ion battery. The gasoline engine provides propulsion and charges the battery via an integrated generator. •
Torque vectoring: Each rear motor can apply positive or negative torque independently to steer the car through corners. For instance, during corner exit, more torque is directed to the outside rear wheel for agile turn-in; during braking, regenerative braking is applied more aggressively to the inside wheel to enhance yaw control.
Operational modes •
Electric Drive (Rear-Motor Only): Powers the vehicle using only the two rear electric motors. Used for low-speed, silent driving and launch acceleration, offering zero tailpipe emissions. •
Engine Drive (Front-Motor Only): At higher speeds with light loads, the front-mounted electric motor and gasoline engine propel the vehicle, while the rear motors regenerate or sit idle, balancing efficiency and power. •
Hybrid Drive (All Motors Active): Under hard acceleration or AWD demand, the gasoline engine and all three electric motors (front + both rear) work together to maximize torque, response, and stability . •
Torque‑Vectoring Regeneration: During cornering and braking, the rear motors apply customized positive or negative torque to each wheel—boosting handling and energy recovery.
Performance & Benefits •
Handling and stability: The feedforward + feedback torque control ensure stability, agile cornering, and confidence-inspiring behavior both in tight turns and during emergency maneuvers, even on low-friction roads. •
Efficiency and power: In the Legend, the SH‑AWD system combines a 3.5 L V6 engine with three electric motors to produce 382 PS (281 kW), delivering V8-level acceleration with fuel consumption similar to a 4‑cylinder engine (16.8 km/L, JC08 cycle) . •
NSX performance: The second-generation NSX leverages this system with a TMU plus a front Direct Drive Motor, enabling yaw control even at low throttle-off conditions. This achieves remarkable linear acceleration and stability. The NSX produces 581 PS and 646 Nm, with a 0:100 km/h time of 3.3 s.
Among the Honda/ Acura car models that are using Sport Hybrid SH-AWD •
Honda Legend (2014) •
Acura RLX Sport Hybrid (2014-2020) •
Acura MDX Sport Hybrid (2017-2020) •
Acura NSX (2016-2022)
Sport Hybrid i‑MMD (Intelligent Multi‑Mode Drive)/ e:HEV Honda's Sport Hybrid i‑MMD (also called e:HEV in latter date) is Honda's second‑generation, two‑motor
series-parallel hybrid powertrain system introduced in June 2013 with the
Honda Accord Hybrid. It combines a petrol engine, two electric motors (a drive motor and a generator motor), and a lithium‑ion battery to offer smooth, efficient, and intelligent hybrid operation. The system has evolved into several versions, optimized for different vehicle classes, from compact hatchbacks to mid-size SUV, by varying motor output, battery capacity, and transmission tuning to suit each application.
System Architecture •
Series‑parallel hybrid layout: At low speeds or during light acceleration, the system operates in Electric Drive, where the drive motor draws electricity from the battery to power the wheels. During moderate loads or acceleration, Hybrid Drive engage, the petrol engine powers the generator motor, which creates electricity to drive the wheels and/or recharge the battery. At steady highway speeds, a clutch connects the engine directly to the wheels in Engine Drive mode. •
Two-motor configuration: •
Drive Motor: Propels the vehicle. •
Generator Motor: Charges the battery and can restart the engine. • These motors are controlled by a Power Control Unit (PCU) that handles electricity flow and cooling via an ATF-cooling loop.
Operational modes •
Electric Drive: Pure electric propulsion at low speeds. Quiet, zero direct CO2 emissions, with typical range of ~2 km depending on conditions. •
Hybrid Drive: The engine acts as a generator powering the drive motor and may recharge the battery during acceleration or moderate loads. •
Engine Drive: At cruising speeds, engine power is routed directly to the wheels via a mechanical clutch for maximum efficiency.
Development and evolution •
2014: Honda launched the first i‑MMD system with the
Accord Hybrid, featuring conventional round‑wire stators, exclusively paired with Honda's
LF series 2.0 L Atkinson-cycle petrol engine. •
2017: The
Clarity Plug‑in Hybrid (2018 model year), marked the debut of the 1.5 L
LEB series Atkinson‑cycle engine paired with the i‑MMD system. •
2019: With the release of
Honda Fit (2020 model year), Honda unified its hybrid models under the e:HEV branding for most markets (excluding America), consolidating the i‑MMD lineup. •
2023: The 2.0 L e:HEV system was updated to a 4th-generation design, first seen on the
CR‑V (2023 model year), featuring a compact parallel motor layout, stronger magnets, and a dual-gear setup, with an additional low range engine gear, allowing higher torque, better efficiency, and improved towing and city driving. This parallel motor layout is also adopted in the latest
Accord, while the
Civic shares the same design but retains an in-line motor configuration, better suited to its compact platform.
Among the Honda car models that are using i-MMD/ e:HEV •
Honda Insight (2018-2022) •
Honda Clarity PHEV (2018-2021) •
Honda Fit e:HEV (Asia/ Europe, since 2020) •
Honda City e:HEV (Asia, since 2020) •
Honda Vezel/HR‑V e:HEV (Asia/ Europe, since 2021) •
Honda Stepwgn Hybrid (Japan, since 2017) •
Honda Odyssey Hybrid (Asia, since 2016) •
Honda Accord Hybrid (since 2013) •
Honda CR-V Hybrid (since 2020) •
Honda ZR-V (since 2022) •
Honda Civic e:HEV (since 2022) == Vehicle Safety Technologies ==