[fpoling]

Indeed. Tesla Model 3 consumes about 50MJ of battery energy per 100 km. Toyota Prius consumes about 4.5 liters of gasoline. That gives roughly 150 MJ. So a electrical car consumes 3 times less or about 33% of energy of one of the best hybrid drivetrain.

[jillesvangurp]

Is that fresh out of the factory or after a few years of service? I think a lot of the metrics around hybrids are a bit optimistic. In the same way that official metrics for EV ranges are usually a bit more than is realistic.

Hybrids running on battery are about as efficient as an EV. When you enter the highway, they turn into ordinary ICE engines. If you use your prius exclusively for traffic in your neighborhood, you only use petrol to charge the battery, which is efficient and about as good as it gets with a hybrid. Unless you can plug it in of course. It won't use any petrol at all in that case.

[Tade0]

I've been driving my hybrid(compact estate) for over 7 years now and there's no noticeable change in fuel economy.

That being said, both the figures mentioned are to me a little bit optimistic.

I don't know about Teslas, but my fuel economy presents itself like this(figures are in litres per 100km):

-City driving: ~5 + ~100ml to bring the engine to working temperature. Checks out to 7 on a 7km drive and falling with distance.

-Highway, so maintaining real 120-140km/h (speed limit around here), 6.3-6.5. Absolute worst was 7.8 during a snowless -20°C night.

-Backroads doing 70-90km/h, average trip speed 50km/h, and here is where I think hybrids shine - 4.0-4.2.

-Hypermiling record: 3.7 as I was steadily rolling at 20-30km/h to a highway onramp a few kilometres away.

Overall fuel economy is nice, but what I like about this car the most is the ease of manoeuvring on the parking lot and very little vibration when the engine is running.

[fpoling]

I bought Toyota Yaris Hybrid in 2012. Toyota at that time claimed it should be 4.4 l/100. My average after 4 years before I sold it was 5.1. So my usage was just 15% off. And this was in Norway with a lot of driving in mountains.

On the other hand with electrical cars that I rented and from what I heard from friends the real range was shorter by 20% or more.

[AtlasBarfed]

Ice hybrids can run on the Atkinson cycle, which fas been explained to me as diesel range from gasoline.

I believe this is because the electric motor can handle the torque variation so the engine runs in a more consistent optimized torque band

[jillesvangurp]

The most optimal thing is to just use ICE engines as a generator/range extender that tops up the battery. Most hydrogen vehicles actually work like that as well: the fuel cell is basically used as a generator to top up the battery.

Some of the Chinese plugin hybrids are starting to do this. Those basically are EVs with a generator bolted on to extend the range to something crazy like well over 1000 miles. These vehicles are far simpler to build and mechanically a lot simpler. And the generator is of course an optional extra if your battery is big enough. More like a safety blanket for the range anxious.

Edison trucks (a Canadian startup) is doing putting generators on their trucks. They've built and designed their own electrical logging truck designed for the extremes of that business. Pretty awesome vehicle. Effortless pulls huge loads over unpaved roads. Basically, it has no gears so it is super simple to operate and it drives like a car. A pretty sporty one even. The generator is just there for when they go out into the middle of nowhere where they can't charge the truck. It's purely a range extender.

If you think about it, you could just buy an off the shelf generator, shove it on a trailer and hook it up to your EV. If you have a EV pickup, you can just sacrifice some space in the back. This isn't that hard. You only need a few kw of output from the generator. A simple, small, and cheap one would be good enough.

The reason companies like Toyota are trying to sell you a much harder to maintain and much more complicated solution instead is not because they haven't thought about it but because they have a large sunken investment in ICE engine manufacturing that they want to milk for a bit longer.

[to11mtm]

> The most optimal thing is to just use ICE engines as a generator/range extender that tops up the battery.

Not necessarily. A pure Series hybrid, at least so far, haven't been able to match up to the series-parallel setup Toyota and Ford is using. And part of the reason for that, is they typically have a 'direct drive' mode, such that the engine is directly connected to the wheels; at that point you can have far less energy lossage via the mechanical drivetrain compared to the loss of mechanical->electrical, even if that electrical was getting dumped straight into the electrical motor.

> If you think about it, you could just buy an off the shelf generator, shove it on a trailer and hook it up to your EV. If you have a EV pickup, you can just sacrifice some space in the back. This isn't that hard. You only need a few kw of output from the generator. A simple, small, and cheap one would be good enough.

The relative efficiency of your typical generator is probably not on the order of most car engines, I'd wager. Especially, again, going back to Toyota/Ford hybrid designs, the engine is can do an atkinson cycle which is more efficient (at the expense of larger engine size to power ratio.) Willing to bet most generators don't have nearly as much/good 'scrubbing' equipment for the exhaust compared to a modern car either.

> The reason companies like Toyota are trying to sell you a much harder to maintain and much more complicated solution instead is not because they haven't thought about it but because they have a large sunken investment in ICE engine manufacturing that they want to milk for a bit longer.

I do still agree with most of this, but TBH a series-hybrid setup (at least for the single speed Aisin units and Ford's HF transmissions to date) can be in many ways wayyy simpler than most modern cars. Lots of em don't even have direct injection, let alone turbochargers, and the gearbox itself is simpler than any modern automatic.

[Tagbert]

What you are describing are series hybrids where the power source generate electricity and the wheels are driven from the electric motor.

Nissan sells this as their E-Power system Hybrid. The Chevy Volt plug-in hybrids were primarily series hybrids when in hybrid mode.

Running the gas engine to charge the battery and drive the wheels is not as efficient as just using a large EV battery but the trade offs in cost, weight, and range may make it worthwhile for now.

[0cf8612b2e1e]

I previously wondered about the generator trailer. Hook it up for long trips and travel without fear.

Can a typical EV battery charge while driving or would they need to be redesigned for this purpose?

[AtlasBarfed]

A generator trailer can be a swappable battery too.

I think this strategy works super well for electric semis.

I think it is being proposed for electric container shops as well.

Finally, I had hopes those ultra compact rotaries would get commercialized as rechargers for phevs and EV range extenders (I think there was a darpa project mentioned two years ago for a novel inside out rotary).

Honestly the emissions for a recharger that gets used maybe 5-15% of the miles driven by a phev aren't that big of a deal.

If it speeds hybrid and full electrification, and the engine runs in a pretty ideal rpm that is lower emission anyway, then civilization is coming out ahead.

[lmz]

But running such a series hybrid with minimal charge of the batteries means almost all power is from the engine. And if that is undersized that won't end well.

[to11mtm]

AKA The Mazda MX30 PHEV. (And a couple of hybrids with similar design from the EU).

The Mazda's rotary gets ~70-75HP if the internet is to be believed. But oh, unlike many PHEVs that have 30-ish miles of range it has 50, so it's got a decently larger battery and starts to get into the 'Where GP is right about plug-in hybrids being marketing fluff'.

My general understanding is that they are a very unpleasant experience in such a state despite whatever range advantages you are given. Because of the relative weight of the batteries to give even 100 miles of range, the small engine isn't that useful on the highway and on a steep hill even less so.