Hybrid electric vehicles (EVs) combine many benefits of internal combustion engines (ICE) and EVs. One of the best hybrid EV technologies comes from Japanese car manufacturer Honda. Called the two-motor hybrid system and able to deliver excellent performance, fuel efficiency, and low emissions, it powers certain versions of the Honda Accord and CR-V. But what makes Honda’s two-motor hybrid system stand out from the rest?
The Honda two-motor hybrid system gets its name from its two electric motors. One is the generator motor that converts mechanical energy into electrical energy that charges the hybrid battery.
The other electric motor is the propulsion motor. Powered by the stored charge in the hybrid battery, the propulsion motor directly drives the wheels and propels the Honda hybrid EV.
Aside from the electric motors, the Honda two-motor hybrid system also uses an Atkinson-cycle gasoline engine. Compared to the Otto-cycle engine in most vehicles, the Atkinson-cycle engine enhances fuel efficiency by shortening the intake stroke while maintaining a full-length expansion stroke. While an Atkinson-cycle type produces less power at lower speeds, the efficient electric motors can compensate for that power loss.
The intelligent power unit (IPU) contains the hybrid battery and the systems that control the power storage device. It regulates the energy flow within the hybrid system, making sure the right amount of power flows between the battery, generator, and propulsion motor. Lightweight and compact, the IPU frees up cargo or passenger space inside the vehicle.
Last but not least is the power control unit (PCU). The control hub for the Honda two-motor hybrid system, the PCU regulates hybrid functions and distributes power according to how you drive and the conditions outside your vehicle. The PCU manages the energy balance between the battery and motors, ensuring the two-motor hybrid system delivers the right performance and efficiency.
Honda is on the fourth generation of its two-motor hybrid system. The latest version rearranges the electric motors into a side-by-side position. The new arrangement frees up space for a more powerful propulsion motor with more torque and higher peak motor speed.
To further enhance the hybrid’s capability and performance, the 4th generation Honda hybrid system features an advanced set of gears and clutches. The Honda Accord and CR-V have a high-speed lockup clutch that reduces engine RPM at high speeds, making cruising on the highway quieter and stress-free.
In addition, the 4th generation Honda two-motor hybrid system has a new Atkinson-cycle 2.0-liter four-cylinder engine. It adds direct multistage fuel injection to produce more power and significantly reduce emissions.
The two-motor hybrid system is available for the front-wheel-drive (FWD) versions of the Honda Accord and CR-V. Additionally, the 4th generation hybrid system is now available for all-wheel drive (AWD) versions of the Honda CR-V.
The Honda two-motor hybrid system manages power distribution and propulsion by running its two electric motors in tandem. It enables the hybrid EV to smoothly accelerate to higher speeds. Also, the hybrid system can cruise at low RPMs when you engage the gasoline engine.
The hybrid system has three driving modes. EV mode relies entirely on electric motors and draws power from the hybrid battery, so it doesn’t burn fuel and produces no emissions or exhaust. If you’re cruising at low speeds or braking, this mode is for you.
In hybrid mode, the propulsion motor drives the wheels while the gasoline engine runs the generator motor. This mode strikes a balance between the engine and battery power, providing the hybrid battery with enough charge to run the electric motors while consuming less fuel.
Last but not least is engine mode. In this mode, a lockup clutch connects the gasoline engine to the drive wheels. Engine mode engages at higher speeds. Instead of going through the transmission like in an ICE vehicle, engine power goes straight to the wheels, resulting in better fuel efficiency when driving at high speeds.
Furthermore, the Honda two-motor hybrid system can run as a series hybrid or a parallel hybrid. A series hybrid draws mechanical power from the electric motor, which runs on electricity from the hybrid battery or gasoline engine. In comparison, a parallel hybrid uses the electric motor and internal combustion engine simultaneously to generate mechanical power.
The Honda two-motor hybrid system can handle daily driving in urban areas and high-speed cruises on highways. When you drive on urban roads, the system usually works as a series hybrid. But when you need to drive fast on a highway, it can run the engine in a parallel mode.
Like many other hybrid systems, the Honda two-motor hybrid system employs regenerative braking. When you hit the brakes, the system collects kinetic energy and turns that captured energy into electricity that can charge the hybrid battery. While regenerative braking alone can’t completely charge the battery, it helps reduce fuel consumption by capturing energy that would otherwise go to waste.
Want to learn more about regenerative braking? Read this article.
The Honda two-motor hybrid system outperforms other vehicles in several ways. First, it has superior fuel efficiency, especially when compared to ICE vehicles. Its two-motor setup also performs better than other hybrid systems.
At the same time, it also delivers better performance. The Honda two-motor hybrid system accelerates more smoothly and can hit higher top speeds, making driving more fun and responsive.
Finally, the two-motor hybrid system takes up less space than other hybrid systems. Its IPU is more compact, freeing up room for cargo and other systems.
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