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BMW i3 REx is pretty much exactly as described. It has a 38 hp twin cylinder motorcycle engine which is more than your ideal 20, but even that is known to slowl

BMW i3 REx is pretty much exactly as described. It has a 38 hp twin cylinder motorcycle engine which is more than your ideal 20, but even that is known to slowly lose charge while climbing long hills since the engine can't output much power. The engine is not mechanically connected to the wheels. Interesting oddity of incentives. California's zero emission vehicle rules state that range extended EVs count for more zero emission credit, but to qualify as range extended the gas range can't exceed the battery range. Since i3 had a pretty small battery and BMW didn't want to go to the expense of building a different, smaller tank for the US they shipped the i3 with a software locked portion of the gas tank. You can flash the firmware to unlock the full gas tank (which is still pretty small). i3 wasn't a huge success. BMW made a bet battery prices would stay extremely high and weight would really matter in an EV. i3 and i8 were experiments to see if they could build cars from carbon fibre re-enforced plastic at scale economically. Spoiler alert: they couldn't. That meant i3 was shockingly expensive to buy and even minor collisions can write the entire car off since even hairline cracks in the CFRP shell can result in catastrophic failure. Unfortunately for you I don't see any new vehicles being designed to fill that niche. Designing a ground up PHEV is far too expensive, so every manufacturer is just electrifying their existing gas designs and stuffing batteries anywhere they can find a spare bit of space. Since engines give off waste heat for free no one is going to bother making a full heating system just for the plug in version since it would drive the sticker price up on a plug-in even higher (and they are already a tough sell since they get up into full EV range). Combined with the charging network getting better very rapidly and PHEVs are a bit of an investment dead end. They will continue to exist (especially in the EU market), but everyone is putting the absolute barest possible engineering effort into them.

fomine3 3y ago
Now there are many PHEVs with heat pump.
jjtheblunt 3y ago
Excellent summary but i bought an i3 (pure electric) in the US in 2014 and it was not shockingly expensive to buy (roughly 1/2 tesla model S) and at 128,000km had only a single service for brake fluid flush. It was awesome but couldn’t go far enough for an only car once we moved to where mountains were over half its range away.
- theluketaylor 3y ago
  i3's were $50,000+ dollar cars when the US average selling price was under $35,000. That's for a supermini car (but well packaged) with a pretty spartan interior. It was selling for the same price as extremely well equipped 3 series and lower end 5 series. I'd call that shocking. The depreciation curve on them was also extreme, since they were worth under 30k within just a couple of years. Much more scary is the repair costs. Yours as the pure electric needed very little, but the REx repairs were expensive. You had to pay BMW dealer prices since it was a weird little engine you couldn't get parts for. And as I said, even minor collision damage was pretty catastrophic.
upon_drumhead 3y ago
How does a software locked fuel tank work? When it gets below x%, it just acts like it's empty and stops the engine?
- theluketaylor 3y ago
  I believe they used the fuel flow monitor that cars have anyway to just shut the fuel pump off after 7.1L when there is actually 9L of fuel in the tank. It's a pressurized tank, so the extra fuel you can't reach takes way longer to go foul. Happily the software fix to remove the restriction is easy to find.
WirelessGigabit 3y ago
The other restriction in the USA is that you cannot turn on the motor at-will. EU engines can enable something like 'hold state of charge' which allows for the ICE to maintain the 75% charge. That way you don't end up at 10% where the engine just can't maintain the charge at all.

fomine3 3y ago

Now there are many PHEVs with heat pump.

jjtheblunt 3y ago

Excellent summary but i bought an i3 (pure electric) in the US in 2014 and it was not shockingly expensive to buy (roughly 1/2 tesla model S) and at 128,000km had only a single service for brake fluid flush. It was awesome but couldn’t go far enough for an only car once we moved to where mountains were over half its range away.

theluketaylor 3y ago
i3's were $50,000+ dollar cars when the US average selling price was under $35,000. That's for a supermini car (but well packaged) with a pretty spartan interior. It was selling for the same price as extremely well equipped 3 series and lower end 5 series. I'd call that shocking. The depreciation curve on them was also extreme, since they were worth under 30k within just a couple of years. Much more scary is the repair costs. Yours as the pure electric needed very little, but the REx repairs were expensive. You had to pay BMW dealer prices since it was a weird little engine you couldn't get parts for. And as I said, even minor collision damage was pretty catastrophic.

upon_drumhead 3y ago

How does a software locked fuel tank work? When it gets below x%, it just acts like it's empty and stops the engine?

theluketaylor 3y ago
I believe they used the fuel flow monitor that cars have anyway to just shut the fuel pump off after 7.1L when there is actually 9L of fuel in the tank. It's a pressurized tank, so the extra fuel you can't reach takes way longer to go foul. Happily the software fix to remove the restriction is easy to find.

WirelessGigabit 3y ago

The other restriction in the USA is that you cannot turn on the motor at-will. EU engines can enable something like 'hold state of charge' which allows for the ICE to maintain the 75% charge. That way you don't end up at 10% where the engine just can't maintain the charge at all.