What is IMA in Honda CRZ?
The Integrated Motor Assist (IMA) in the Honda CR-Z is Honda’s mild-hybrid system that couples a small electric motor with the 1.5-liter gasoline engine to provide torque boost and to recapture energy during braking. It is not a plug-in or fully electric propulsion system, and the car cannot be driven on electric power alone.
What Integrated Motor Assist means for the CR-Z
IMA represents Honda’s approach to improving efficiency by adding an electric motor that assists the gasoline engine, rather than replacing it with an electric drivetrain. In the CR-Z, this setup is designed to smooth starts, boost acceleration at low to moderate speeds, and recover energy through regenerative braking.
- The electric motor assists the gasoline engine during acceleration, providing extra torque when you need it.
- During braking or deceleration, the system regenerates energy and stores it in a high-voltage battery pack for later use.
- It operates as a mild-hybrid, meaning there is no pure-electric driving mode and no external charging port.
In practice, the IMA helps the CR-Z improve fuel economy by reducing the workload on the gasoline engine in everyday driving, especially at city speeds, while maintaining familiar driving characteristics.
Hardware and how it’s implemented in the CR-Z
The CR-Z pairs a 1.5-liter i-VTEC gasoline engine with Honda’s IMA electric motor, all managed by an onboard control system that coordinates torque split and energy recovery. The system uses a dedicated high-voltage battery pack to store the recovered energy.
- The electric motor is integrated with the engine’s architecture to provide assist when needed.
- The high-voltage battery pack is typically a nickel-metal hydride (Ni-MH) type in many IMA-equipped Hondas of that era.
- The Intelligent Control Unit determines when to deploy electric assist or regenerative braking to optimize efficiency and smoothness.
Because it’s a mild-hybrid setup, the IMA’s electric motor serves as an assistant rather than a standalone drive unit, and the CR-Z relies on the gasoline engine for most of its propulsion.
Driving experience, efficiency, and limitations
Drivers may notice smoother starts and more responsive acceleration at lower speeds thanks to the electric assist, which can help the CR-Z feel more eager around town. However, the system does not offer electric-only driving and cannot be charged via plugging in, so fuel economy gains come primarily from assist during acceleration and energy recovery during braking.
Legacy and context in Honda’s hybrid lineup
IMA was Honda’s early foray into integrated motor assist technology and appeared in several models before Honda shifted toward more advanced two-motor hybrid systems. The CR-Z, produced from 2010 to 2016, is one of the last mainstream models to use the IMA approach in a modern, light-hybrid form. In later years, Honda has moved to more sophisticated e-CVT hybrids with dual-motor architecture (often referred to in markets as i-MMD or e:HEV), which allow greater electrified driving capability and efficiency. The CR-Z itself is no longer in production, and Honda’s contemporary hybrids emphasize these newer architectures for improved performance and efficiency.
Summary
IMA stands for Integrated Motor Assist, Honda’s mild-hybrid system used in the CR-Z. It adds a small electric motor to help the gasoline engine and recapture energy, boosting efficiency without enabling electric-only driving or external charging. As Honda’s hybrid technology evolved, newer models adopted more advanced two-motor systems, while the CR-Z remains a notable example of early hybrid innovation.
