TFA is exactly that...

I think it's also because EREVs need a performant generator that isn't much different from the drive motor. So you'll have a full ICE+EV drivetrain on top of an EV as its battery for it to work, which is not ideal.

Compared to that, other hybrid systems like the motor-clutch combo packs that sit between the ICE and gearbox, as well as the fixed gear Toyota systems, can have motors that are weaker, lighter, and cheaper than the ICE, while being able to be additive to the ICE power output. That makes more efficient use of steel and copper than full serial setups.

BMW i3 had such EREV option, but it apparently used a cheap OEM bike engine(not like a BMW Motorrad engine) and also could not overcome power draw of the EV drive motor. So it literally just extended the range, not allowing it to run indefinitely at highway speeds with just refueling. Nissan e-POWER system is powerful enough to do that, but then the readers of comment will have to back to the line 3.

That is exactly what ePOWER is, that configuration is called a series hybrid and is more commonly seen in heavy industry like diesel trains or trucks in the mines (for better or worse).

More recently effort is also going into series hybrids for public road haulers, which I personally think is a great application for it since you can potentially put a lot of the equipment into a hot-swappable dolly.

I drove a Nissan Note (Nismo esition) with ePower and it could happily spin the wheels when taking off, not something you normally get out of a tiny economy hatchback. I think it has 140kw electric drivetrain? 140kw is pretty sporty when delivered instantly.

Range extender EVs made a lot more sense a decade a go when batteries were much more expensive, and fast chargers were not yet ubiquitous. Then range extenders were more affordable than EVs and could go to places EVs couldn't.

Now these EREVs are mostly luxury niche of big cars (where extra space taken by two power trains doesn't matter) for people who don't want to spend 20 minutes at rapid chargers on that yearly long trip they do. Or for people who live in some global warming ignoring backwater[1] that hasn't built out rapid charger yet.

[1] even China has ubiquitous fast charging network now

What you are referring to is usually referred to as an EREV (Extended Range Electrical Vehicle). The reason legacy manufacturers market their less efficient plugin hybrid and non plugin hybrids (100% of the power comes from petrol) instead is because that's what they have and want to milk for as long as possible. In terms of drive train these are more complex to manufacture and more costly to maintain than an EREV. EREVs typically have slightly larger batteries than a typical PHEV as well. Typical electrical ranges are at least 80-100 miles or more in some cases. Usually the cars are available as without the range extender as well. This is less common for PHEVs and hybrids. Though of course some legacy manufacturers are still trying to push compromise cars. Like Nissan in this case.

Nissan has been really struggling for the last few years, this new hybrid engine doesn't look like it will turn things around for them to me.

EREVs are an idea that is not new and also relevant in shipping and aviation. Many modern large ships (oil tankers, cruise ships, etc.) are already EREVs effectively: an electrical motor drives the propeller and a generator powers the motor.

And there are are a few plane designs that are using small batteries + generators to power flight. It makes a lot of sense: electrical motors are a lot simpler, lighter and cheaper to maintain. Engine maintenance is very costly in aviation. And so is fuel. The recently announced X1 is a good example of a plane that does this. There are a few other manufacturers working on this as well. Early days but the potentially large fuel savings probably ensure this is going to happen one way or another.

There’s a lot of good replies here but I’ll add mine too:

The simples reason is this. What you’re describing is having a gas motor spin a thing (the generator) -> charge battery -> discharge battery -> spin a thing (the wheels) to make car go. Each of those steps has efficiency losses.

That’s why most hybrids are parallel hybrids, where both the gas engine and the battery+motors can spin the wheels more or less directly, even at the same time.

you still basically get the engine spinning at a more constant rpm, and the battery kicks in for acceleration (and charges on deceleration), and now highway cruising doesn’t have any lossy conversion steps, while acceleration and braking uses the advantages of the electric drive chain.

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

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

Ford and Ram are both doing this with their next generation electric pickups. Range and towing on pure electric was deemed too compromised.

https://www.motortrend.com/features/what-is-an-erev-extended...

Not for cars, but Edison Motors in Canada seems to be going this route right now for their heavy duty trucks and heavy-duty pickup truck conversions.

Disclosure: I have a small investment in them.

That's pretty much how the Chevy Volt worked. It was an incredibly good system in that car and GM did their usual thing and killed it

It seems to me you’re talking about a range extender, which lots of Chinese EV makers use. Many do buy them but sometimes you get the worst of both worlds: weighty like an EV and the heat, vibration, exhaust of a petro car. For most people the extended range is only needed very occasionally but you have to carry the ICE system the whole time.

The original/first BMW i3 (2013) was like this, full battery electric (with an admittedly small battery 80-160 miles range depending on model), with an "range extender" engine.

Personally I'm a big fan of the EREV (which only drives an alternator, rather than a PHEV which drives the wheels directly) due to the simpler mechanical design - however I'm not sure if it's a personal preference. I feel even a fairly small 30kw (40hp?) would make a huge difference to the utility of the vehicle, while still being small and economical.

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.

You may be interested to read / watch videos of Audi's RS Q e-tron they raced in the Dakar Rally and even won with this type of powertrain - https://en.wikipedia.org/wiki/Audi_RS_Q_e-tron

The above comment’s video explains why.

You lose energy converting the the gas power to electrical power to mechanical power. Constant RPM doesn’t matter as much as you think.

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

the ICE extender was an option.

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?

Already a big push with this. They call them EREV now, extended range electric vehicles.

Isn’t that how diesel trains operate?

Honda's current hybrid system and this e-POWER both work this way mostly

You mean like a BMW i3 with a range extender? Little two-cylinder petrol that just spins a genny.

They work, they're not terribly efficient in terms of converting fuel to distance travelled, and really batteries are getting so good these days there's little point any more.

The concept is called range extenders, and the video does explain why it’s one of those false great ideas and every production vehicle has failed: EVs with range extenders are at best bad EVs and at worst terrible hybrids.

Edison in Canada is doing diesel electric hybrid trucks

[dead]

Aka EREV, thats becoming majority of “PHEVs” now.