Higher fuel economy and
the fun of the drive
are the essence of this
uniquely Honda hybrid
openclose
- Table of Contents
- Overview of e:HEV
- Advantages of e:HEV 2-motor hybrid
- 3 modes
An original hybrid approach delivers both
environmental responsibility and fun driving
As a mobility manufacturer dedicated to helping solve the critical issue of CO2 emissions, Honda has for decades been engaged in developing a full range of vehicle electrification technologies. As part of this initiative, Honda is further expanding its lineup of hybrid vehicles, which are currently among the most accessible electrified vehicles.
Hybrid technology improves fuel economy by efficiently using two sources of power: a motor and a gasoline engine.
The e:HEV hybrid system combines all of Honda's gasoline engine and electrification technologies with an array of other advanced technologies to achieve exceptionally low fuel consumption and a new level of driving pleasure.
While a motor operate throughout the low- to high-speed range, e:HEV relies on the gasoline engine alone for high-speed cruising. Through this configuration, the system realizes a unique combination of environmental performance and driving pleasure that could not be achieved with an engine-only system.
Honda's unique e:HEV hybrid
combines the best of motors and engines
While a gasoline engine can produce high output at high rpm, it has difficulty generating torque at low speeds, such as when starting off, and its fuel economy is poor in the stop-and-go traffic of city driving. In contrast, a motor can generate maximum torque even at low speeds, including when starting off. Hybrid vehicles improve efficiency and fuel economy by using two different sources of power: motors, to high speeds, and gasoline engines, which excel at high speeds.
Around the world, automakers have developed a wide variety of hybrid systems, matching them to models based on size and other factors.
In general, there are three types of hybrid systems: the series hybrid system, in which the gasoline engine generates electricity and the motor alone provides power to the wheels; the parallel system, in which the engine is primarily responsible for providing power to the wheels and the motor assists; and the series/parallel system, in which both the engine and motor can provide power to the wheels.
At low to medium speeds, at which the motor excels, e:HEV operates as a series system, providing power to the wheels with the traction motor alone. In high-speed cruising, in which the gasoline engine excels, e:HEV operates as a parallel system, simply connecting the engine directly to the wheels to provide power. Unique to Honda, this innovative hybrid system leverages the best features of both the series and parallel systems.
■ Differences between e:HEV and other hybrid systems
Differences with series/parallel hybrid system
A series/parallel system adjusts the ratio of power provided by the gasoline engine and motor based on driving conditions. In contrast, e:HEV depends mostly on more efficient motor power in daily driving, switching as needed between EV Mode and Hybrid Mode. Thanks to its simple structure with no complicated power-dividing mechanism, e:HEV can leverage its traction motor to maximum effect and deliver both outstanding performance and efficiency.
Differences with series hybrid system
A series hybrid system uses the gasoline engine to generate electricity and the motor to drive the wheels. In high-speed cruising, the motor operates with reduced efficiency, requiring the gasoline engine to generate more electricity in order to maintain high motor rpms. In contrast, e:HEV leverages the greater efficiency of the gasoline engine at higher speeds by simply connecting it directly to the wheels, resulting in quiet, fuel-efficient cruising.
■ e:HEV system overview
1) Electric CVT with 2 motors
The system comprises a generator motor, a traction motor, and a clutch connected directly to the engine. The two motors efficiently convert engine output into electricity, provide mechanical power to the wheels, and help turn regenerative braking energy into electricity. The traction motor incorporates magnets that are free of heavy rare earth metals.
2) Atkinson Cycle DOHC engine
High-output Atkinson cycle engine with superior thermal efficiency.
3) Directly connected engine clutch
During high-speed cruising, the system enters Engine Drive Mode, directly connecting the engine output shaft to the wheels. Equivalent to the top gear in a manual transmission, this gear ratio is optimal for high-speed cruising, while the simple power transmission pathway takes maximum advantage of the highly efficient Atkinson cycle engine.
4) Power control unit (PCU)
The PCU is equipped with a power drive unit (PCU) that converts battery current to AC, and a voltage control unit (VCU) that boosts voltage to the maximum 650V required by the traction motor. Thanks to its compact size and efficiency, the PCU can be mounted in the engine compartment.
5) Intelligent Power Unit (IPU)
This power supply unit integrates a lithium-ion battery with a control ECU and other components. It offers excellent efficiency in storing and outputting power, greatly contributing to fuel economy and driving performance.
Traction motor + Generator motor for simplicity + High efficiency
The two-motor hybrid system features both a traction motor and a generator motor. The traction motor is directly connected to the drive shaft and regenerates electricity during deceleration, while the generator motor is directly connected to the engine. The simple system requires no power-dividing mechanism or transmission and avoids the friction loss they cause, directly leveraging the characteristics of the high-efficiency traction motor to deliver power with exceptional smoothness. The direct connection of the traction motor to the engine similarly avoids a loss of energy.
