944K views · Dec 13, 2020 · 25:15 · 2 HN recommenders · 3 mentions · discussed 2024–2025
WeberAuto explains how the Honda E-Drive (i-MMD) hybrid transaxle works in the CR-V, Accord, Insight and Clarity hybrids. It walks through the system's three modes of operation.
Why Hacker News points people here: HN recommends it as a clear explanation of a mind-blowingly simple power-split hybrid design.
“Some of these designs are mind-blowingly simple. My favorite is Honda's E-drive”HN comment, 2024
“Some of these designs are mind-blowingly simple. My favorite is Honda's E-drive”
Explains Honda's simple e-drive power-split hybrid design.
I wish more people knew how the power-split devices in modern hybrids worked. The 'eCVT' and similar terminology they often get just doesn't do it justice. They're a beautiful design, and entirely different than 'CVTs' as most people know them. Some of these designs are mind-blowingly simple. My favorite is Honda's E-drive: this video
“has more info.”
More detail on how Honda hybrids drive the wheels.
Current Honda hybrids are like that. The only time the Internal Combustion Engine (ICE) is directly connected to the drive train is when the speed gets to above around 60MPH. The rest of the time the ICE is used to power a generator which then sends power to the electric motor and/or the battery pack. this video has more info.
“Another one from WeberAuto like in my parent comment, this time on the (apparently very similar) Honda system”
Another WeberAuto video on the similar Honda hybrid system.
More YouTube videos about the eCVT... 1) Better -- much simpler, and above all shorter -- video explanation of the Toyota system: link . 2) Another, a little longer, but very pedagogical and beautifully animated explanation: link . Eight years old, but apparently the "power split device" worked the same even then. Bonus -- short conversation in the comments, arriving at the same conclusion I did above: @TimpBizkit 3 weeks ago I thought the prius had a cvt 1 reply @aspecreviews 3 weeks ago It doesn't. The "CVT" is electrically simulated. Heh, yeah. 3) Titled something about "Launch Gear", but actually on the whole CVT thing (from a channel I semi-regularly watch): link . 4) A good basic look-through of the various types of CVT and their history: link . 5) Long and thorough explanation of the Prius powertrain: link . Uses a cutaway of the actual transmission, so good for getting a more concrete picture than e.g. #2 above. But... Long. 6) Another one from WeberAuto like in my parent comment, this time on the (apparently very similar) Honda system: this video . So likely to be about as good as the previous one, but... 25 minutes more of this? Naah, I've had enough. There were also some from Scotty Kilmer et al, but... The less said, the better. The ones I'd most recommend are #4 for general CVT stuff and #2 for the Prius e-CVT's operating principle specifically. Well well, all in all that was quite the rabbit hole.
