Yet another Hacker News

Nissan's third generation e-POWER powertrain

19 points mroche 1 hour ago 11 comments

gcanyon 1 hour ago | parent

One thing that always puzzled me was how the gas engines in hybrids were so efficient. Technology Connections has a great video explainer: https://www.youtube.com/watch?v=KnUFH5GX_fI

tl;dw: constant RPM and a weird stroke geometry where the power stroke is longer than the other strokes to extract more energy from the expanding gasses.

jostmey 57 minutes ago | parent

I'm surprised there isn't more effort to create hybrids in reverse--an electric car with optional gas generator. The gas generator could run at constant speed, never changing RMP, while the battery handles constant changes in acceleration. The idea is not mine. I've heard about it in China

serf 52 minutes ago | parent

bmw I3s were this type of hybrid as far as I remember.

the ICE extender was an option.

jasonwatkinspdx 49 minutes ago | parent

Yup, my friends had one and loved it despite the... unique styling.

They live in the Puget Sound area, and both work at the same place. It worked out to where they could do their commute, and ordinary errands entirely on battery, and only needed the range extender if they were going into downtown Seattle or on a road trip or such.

sjtrny 49 minutes ago | parent

Chevrolet Volt (2011) https://en.wikipedia.org/wiki/Extended-range_electric_vehicl...

Twirrim 30 minutes ago | parent

The volt was never popular enough, unfortunately. Right around the time we were looking to buy a new car, and had the Volt high on our list, the retired the product line.

cyberax 32 minutes ago | parent

There were several of them: the first and second generations of Chevy Volt, Fisker Karma, BMW i3, and a couple of Chinese brands.

They're less efficient than parallel hybrids at high speeds (on a freeway). And you also need a fairly sizeable engine to keep up with the consumption at freeway speed, so at this point you might as well just throw in a planetary gearbox.

jackvalentine 13 minutes ago | parent

This is how BYD does it. (It also can apparently drive the front wheels with a clutch)

https://bydautomotive.com.au/shark-6

janzer 11 minutes ago | parent

Just a note: the Technology Connections video above goes over why this doesn't work well for cars (but does for train locomotives).

geokon 5 minutes ago | parent

Theoretically couldn't you take an electric car and put an off-the-shelf generator in your frunk and wire it up to charge the battery as you drive?

instagib 57 minutes ago | parent

Hopefully it’s better than the second gen. Gas engine front only puts power to one wheel and electric rear only puts power to one wheel while the other two sit idle. Bad state for a mild 4x4 unless you keep it on pavement.