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Discussion Starter · #1 ·
I have been trying to get some more information on how the Honda eCVT works, but google doesn't have much information on the Insight eCVT in particular.

I know the Prius uses 2 Planetary Gear sets, one of m1 and one on m2 that join together to drive the wheels, but I am not sure if the Honda is the same, or if it uses the metal V belt like in traditional CVTs. I am also looking for information on how the engine directly drives the wheels sometimes?

Does anyone have any information on the Insight eCVT?

836 Posts
From what I understand.

At all speeds the electric motors drive the wheels, either in series or parallel to maximize efficiency. (Series for lower speeds, parallel for highway speeds). At speeds above 45 mph, the engine can engage the single gear to power the wheels directly. I do know that the car does in fact have transmission fluid. Whether that's used as a cooling aid, and/or clutch activation, I'm not 100% sure.

I hope that helps. From a traditional standpoint, there is no transmission between the ICE and the wheels, just a single fixed gear.

At least that's my basic understanding of the system.

I found this much better explanation when searching google for Honda 2 motor hybrid system.
2018 Honda Accord Hybrid features third-generation MMD two-motor system; no heavy rare-earth metals in motors

An excerpt from that article:
Drive Force Transfer. Just like the previous model, the Accord Hybrid is not equipped with a conventional mechanical transmission. Instead, motive force transfer is accomplished through the interaction of the Accord Hybrid’s gasoline engine and two electric motors. Coordinated by the IPU, this form of drive force transfer offers smooth and predictable acceleration matched with efficient low-rpm highway cruising when the gasoline engine is in operation. Gasoline engine shutdown is seamlessly integrated into the operation of the Accord Hybrid when appropriate.

The drive force transfer system operates without the need for a torque converter, mechanical pulley or belt. It instead uses two motors for driving and generating power. The system is optimally and rapidly able to control both engine and electric motor rotation in order to deliver higher fuel efficiency and quicker engine response in each driving mode.

When cruising at mid- or high-speeds in the high-efficiency range of the engine, a lock-up clutch is engaged, connecting the drive motor to the generator motor to transmit engine torque directly to the drive wheels as efficiently as possible. In EV Drive operation, when the battery-powered drive motor is used for either acceleration or regenerative braking, a clutch disengages the stopped gasoline engine from the drivetrain to eliminate efficiency loss from mechanical friction in the engine.

Improving efficiency and reducing weight and size, the drive force transfer system of the second-generation i-MMD integrates the torque limiter within the flywheel.

And yes, I know it's about the accord hybrid, but it's the same system used in the 3rd Generation Insight.

Premium Member
4,843 Posts
I like the transmission recap from this (non-Honda) Serviceability Report for the 2019 Insight. It describes the Insight's two-motor eCVT transmission as 'the art of simplicity.'

Here is how it works:
  • There is no 12-volt starter motor as in the previous IMA system.
  • One motor (MG1) starts the ICE when the single clutch is open.
  • MG1 can also act as a generator when the clutch is open and the ICE is running.
  • When the clutch is closed and the car is moving, MG1 is a generator.
  • A second motor (MG2) powers the wheels when the clutch is open, both forward and reverse.
  • When slowing down with the ICE off and the clutch open, MG2 is a generator and works with the recuperative braking system to add electrical energy back into the Li-ion battery pack.
  • When the clutch is "open" the car can be driven in EV mode with or without the ICE running.
  • When the Li-ion battery is low on a charge the ICE starts and MG1 is now a generator adding electricity to the high voltage battery and the inverter for MG2.
  • With the clutch closed, the ICE can take over all power requirements and the Insight becomes a gas car.
  • Without an alternator, MG1 and MG2 are spinning so one will be a generator and keep the HV battery charged enough to keep everything powered up.
  • The clutch can only close when the ICE is in the correct rpm range to the road speed. At that point it is direct drive with no way to change the gear ratio.
  • If you need more power than the ICE can contribute, MG2 will become a motor and add that extra torque to the drive wheels.
  • No planetary gear set as in the Toyota and Ford design but it has the same effect.


520 Posts
I can't believe I just found this post.. I am a total nerd and loved reading the white papers, in particular the one of Electro Servo Braking and intelligent Power Unit. It's amazing that the IPU outputs 700 volts @ 400Kva! I know this may vary slightly for our Insight, but not by much! Also reading about Agile Handling Assist was very interesting, it's amazing how many high tech systems were built into these cars at an affordable price!
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