5 ms·

The term for that is a hybrid series powertrain. It allows one to optimize the generator to run at a single RPM, which leads to efficiency benefits.

euroderf 2y ago
FWIW back in the 80s Mother Earth News had plans for a car that used this principle.
- Loughla 2y ago
  I genuinely believe hybrid cars will be the path once we get the itch for electric cars out of our system. You get all the good parts of each engine type, with less of the bad parts of the other type.
  - gambiting 2y ago
    I have a PHEV and I genuienly believe this is the best combination of both, it's so practical with upsides of both drivetrains, but also let's not kid ourselves - PHEVs are vastly more complicated than either just plain ICE or EV cars, you have a lot more stuff that can go wrong. I deal with it by just buying extended warranty for as long as they let me lol, but it's definitely a concern with them.
    - Lwerewolf 2y ago
      The Prius and other HSD cars (i.e anything with a power-split device of the Toyota variety - input-split PSD) are some of, if not flat out the most reliable and simple ICE cars. Permanent atkinson-cycle engine, no turbos because there's no exhaust gas pressure to drive them in the first place (and if there was, it'd be an inefficiency to be rooted out), bulletproof starter/generator especially since the ls600h (double-sided cooling of IGBTs >> no usual IGBT packaging degradation-related failure modes - this was NOT the setup on the 3rd gen prius), still a very efficient power transfer from the engine to the wheels (a big percent is still transferred mechanically), etc, etc. Adding a bigger battery to those isn't a whole lot of increased complexity. The only issue is making a PHEV that has the same performance characteristics in both EV and hybrid mode - not that it hasn't been done. Specifically on HSD cars, the two electric motors combined, or even just MG2 (the "motor") have way more power than you'd assume - they actually function as an AC-AC converter, converting a significant portion of the engine's output power from mechanical to electric and back to mechanical again. It's essentially the way the eCVT works. Therefore, with a battery (and buck-boost converter) that can support such a load, they can propel the car alone way more than adequately - with a speed limit to protect the "generator" from too high RPM, due to the way the HSD works. Anyways, it absolutely can be done and it absolutely can be way simpler. If it's a case of a typical modern ICE with a big battery and a motor thrown in somewhere that makes it "hybrid"-ish - i.e. all the ICE complexity + the EV "complexity" (minus the classic starter/alternator) - yeah, no thanks. IMO: Good examples - the Chrysler Pacifica PHEV. Bad examples - C63 AMG (the PHEV version).
      - robocat 2y ago
        > bulletproof starter I was told this is not true for 2006 Alphard hybrid (I have one). ~USD1000 part (usually old Toyotas have cheaper parts). And beware that older hybrids use small (e.g. 50Wh) NiMH batteries - I think they started to change to Lithium in 2017 or something
        CarVac 2y ago
        The Alphard hybrid had a belt CVT, rather than a power-split-device hybrid. https://toyota-club.net/files/faq/21-11-20_faq_hybrid_thsc_en.htm https://toyota-club.net/files/faq/21-11-20_faq_hybrid_thsc_e... "Hybrid repair experts have called the first generation Estima (AHR10) Toyota's most problematic hybrid vehicle ever."
    - wiredfool 2y ago
      I think a PHEV would be ideal for me -- Bimodal use, mostly a few km trips, and then a few 1000km trips/yr. The long trips are the ones where we wind up filling the car, so space inside/towing is important. (We've got a 7 seater, used to be a renault grand scenic, now a ford galaxy). OTOH, one of the last times I rented a car, they 'upgraded' me to a PHEV, and I wasn't impressed. It was a tight fit with the kids + luggage, and we didn't even have the dog along. Fuel economy was well worse than plain old diesel, because it turns out when they give you a PHEV with 0km in the battery, it's not much of a hybrid. (This was a Volvo S60).
      - gambiting 2y ago
        Ours is an XC60 T8 and yeah, I do 90% of my day to day driving in EV mode, then few very long distance trips on fuel. But yeah, not much use if it's not charged.
  - rootusrootus 2y ago
    What would you say the bad part is for a BEV? Personally I hope to never drive another gas-powered vehicle, hybrid or not. I'm very much addicted to the convenience and performance of modern BEVs.
    - gambiting 2y ago
      I drive across Europe few times a year and covering 800 miles in one day is difficult to do in almost every BEV, maybe with the exception of Teslas. Also I had to deal with chargers in Germany a few times and it's been a pain every time(the classic - charger requires an account, the account only accepts german-registered payment card). But I'm also perfectly happy to admit that it's fine and doable just requires adjustment of expectations, and even the charging network thing I'm sure has solutions if you plan beforehand.
      - spockz 2y ago
        I got the tip from other BEV users for charging in Germany to go off the highway and find something like a shopping center/mall. There they had always plenty fast chargers and something convenient to do as well. Their built in navigation showed them the way. (This was bmw, not Tesla.)
      - thatfrenchguy 2y ago
        I mean, you can use Tesla chargers with any car these days in the EU?
        brnt 2y ago
        But they are a tiny minority of charging point, the market is quite diverse in Europe. And this whole setting up account, installing apps for each and every company, different in each and every country, is really off putting. I have no idea why they don't just use the kind of dumb payment terminals every unmanned carbohydrate station uses. Works with any card from any country all the time.
      - rootusrootus 2y ago
  - elihu 2y ago
    Continuing to burn fossil fuels forever isn't really an option. At some point we'll effectively run out, but before then we'll have caused catastrophic climate change due to our CO2 emissions. Synthetic or plant-based fuels are plausible options, but synthetic fuels can't compare with battery EVs in terms of energy efficiency, and plant based fuels need crop land that's probably better used to grow food. Electric vehicles aren't a temporary fad. They're here to stay. Liquid fuels aren't going away either, but I expect eventually they'll be used mostly for military and aviation applications, not ground transportation.
    - amluto 2y ago
      > synthetic fuels can't compare with battery EVs in terms of energy efficiency, This is almost meaningless. If you are turning renewable energy sources into either synthetic fuel or grid power, then efficiency is irrelevant. What matters is cost (of the whole system, including distribution of the energy) and emissions (burning even carbon-neutral methane or hydrogen isn’t quite zero emission). There are startups working synthesizing fuels from air and solar energy, and they argue, fairly convincingly, that bypassing the entire electrical distribution network can more than make up for extremely low efficiency. Also, heavier vehicles likely emit more brake and tire dust than lighter vehicles, and a series hybrid can be much lighter than a long range BEV.
      - elihu 2y ago
        Of course efficiency matters, because electrical energy is a bottleneck resource. Renewables may be cheap, but they aren't free and we have a lot of other things we need that energy for. If you can make a car go 4 miles with 1kwh of electrical input, that's much better than a car that can got 2 or 3 miles with the same input. Multiply that by the ~1.5 billion cars/trucks in the world presently and that's a huge difference. Burning liquid fuel in a heat engine typically wastes about 2/3 of the chemical energy as heat. Hybrids do better, but there's only so much you can do. I don't know what the state of the art for synthesizing liquid fuel is, but I assume there's some significant energy loss there too. On the other hand, modern permanent-magnet electric motors can be around 95% efficient. Lithium ion batteries typically have coulombic efficiency better than 99%. Actual energy efficiency is a little less due to internal resistance (it takes a higher voltage to charge the battery than you get out when you drain it, so even if amp-hours in is almost equal to amp-hours out, watt hours might be a little different). Charging circuitry also tends to be pretty efficient. Battery-electric drive trains are already so close to optimal efficiency that there's very little that they can actually be improved on, and nothing else comes close. The tire dust microplastics thing is a real problem, but it's not that much worse for EVs than other cars. Brake dust is much less of an issue on BEVs and hybrids, due to regenerative braking. Personally I hope the idea of BEVs that haul around 800 pound batteries goes out of fashion (and it might if we could be bothered to electrify our major highways to make huge batteries largely unnecessary), and I also hope cars in general start to get smaller and less numerous. But I think cars are basically here to stay in some form, so they might as well be electric.
rsynnott 2y ago
Some buses also use these. Dublin Bus has a particularly disconcerting plugin hybrid variety; if it’s using the diesel engine, that runs constantly (so it’s noisier than a normal bus at rest) but if on battery, it’s silent. There are few things more unnerving than a double decker bus gliding along virtually noiselessly (their pure-electric buses, somehow, are noisier). Double-decker buses are supposed to sound like they might explode at any moment, like in the good old days. (/s, just in case; ye olde 20 tonne 1980s buses were extremely noisy, and it was not great.)
drmpeg 2y ago
The other problem it solves is the complex transmission required. Diesel-Hydraulic locomotives were built, but were not successful long term. The most famous is the Krauss-Maffei ML4000, built for the Southern Pacific railroad. https://en.wikipedia.org/wiki/Krauss-Maffei_ML_4000 https://en.wikipedia.org/wiki/Krauss-Maffei_ML_4000

euroderf 2y ago

FWIW back in the 80s Mother Earth News had plans for a car that used this principle.

Loughla 2y ago
I genuinely believe hybrid cars will be the path once we get the itch for electric cars out of our system. You get all the good parts of each engine type, with less of the bad parts of the other type.
- gambiting 2y ago
  I have a PHEV and I genuienly believe this is the best combination of both, it's so practical with upsides of both drivetrains, but also let's not kid ourselves - PHEVs are vastly more complicated than either just plain ICE or EV cars, you have a lot more stuff that can go wrong. I deal with it by just buying extended warranty for as long as they let me lol, but it's definitely a concern with them.
  - Lwerewolf 2y ago
    The Prius and other HSD cars (i.e anything with a power-split device of the Toyota variety - input-split PSD) are some of, if not flat out the most reliable and simple ICE cars. Permanent atkinson-cycle engine, no turbos because there's no exhaust gas pressure to drive them in the first place (and if there was, it'd be an inefficiency to be rooted out), bulletproof starter/generator especially since the ls600h (double-sided cooling of IGBTs >> no usual IGBT packaging degradation-related failure modes - this was NOT the setup on the 3rd gen prius), still a very efficient power transfer from the engine to the wheels (a big percent is still transferred mechanically), etc, etc. Adding a bigger battery to those isn't a whole lot of increased complexity. The only issue is making a PHEV that has the same performance characteristics in both EV and hybrid mode - not that it hasn't been done. Specifically on HSD cars, the two electric motors combined, or even just MG2 (the "motor") have way more power than you'd assume - they actually function as an AC-AC converter, converting a significant portion of the engine's output power from mechanical to electric and back to mechanical again. It's essentially the way the eCVT works. Therefore, with a battery (and buck-boost converter) that can support such a load, they can propel the car alone way more than adequately - with a speed limit to protect the "generator" from too high RPM, due to the way the HSD works. Anyways, it absolutely can be done and it absolutely can be way simpler. If it's a case of a typical modern ICE with a big battery and a motor thrown in somewhere that makes it "hybrid"-ish - i.e. all the ICE complexity + the EV "complexity" (minus the classic starter/alternator) - yeah, no thanks. IMO: Good examples - the Chrysler Pacifica PHEV. Bad examples - C63 AMG (the PHEV version).
    - robocat 2y ago
      > bulletproof starter I was told this is not true for 2006 Alphard hybrid (I have one). ~USD1000 part (usually old Toyotas have cheaper parts). And beware that older hybrids use small (e.g. 50Wh) NiMH batteries - I think they started to change to Lithium in 2017 or something
      - CarVac 2y ago
        The Alphard hybrid had a belt CVT, rather than a power-split-device hybrid. https://toyota-club.net/files/faq/21-11-20_faq_hybrid_thsc_en.htm https://toyota-club.net/files/faq/21-11-20_faq_hybrid_thsc_e... "Hybrid repair experts have called the first generation Estima (AHR10) Toyota's most problematic hybrid vehicle ever."
  - wiredfool 2y ago
    I think a PHEV would be ideal for me -- Bimodal use, mostly a few km trips, and then a few 1000km trips/yr. The long trips are the ones where we wind up filling the car, so space inside/towing is important. (We've got a 7 seater, used to be a renault grand scenic, now a ford galaxy). OTOH, one of the last times I rented a car, they 'upgraded' me to a PHEV, and I wasn't impressed. It was a tight fit with the kids + luggage, and we didn't even have the dog along. Fuel economy was well worse than plain old diesel, because it turns out when they give you a PHEV with 0km in the battery, it's not much of a hybrid. (This was a Volvo S60).
    - gambiting 2y ago
      Ours is an XC60 T8 and yeah, I do 90% of my day to day driving in EV mode, then few very long distance trips on fuel. But yeah, not much use if it's not charged.
- rootusrootus 2y ago
  What would you say the bad part is for a BEV? Personally I hope to never drive another gas-powered vehicle, hybrid or not. I'm very much addicted to the convenience and performance of modern BEVs.
  - gambiting 2y ago
    I drive across Europe few times a year and covering 800 miles in one day is difficult to do in almost every BEV, maybe with the exception of Teslas. Also I had to deal with chargers in Germany a few times and it's been a pain every time(the classic - charger requires an account, the account only accepts german-registered payment card). But I'm also perfectly happy to admit that it's fine and doable just requires adjustment of expectations, and even the charging network thing I'm sure has solutions if you plan beforehand.
    - spockz 2y ago
      I got the tip from other BEV users for charging in Germany to go off the highway and find something like a shopping center/mall. There they had always plenty fast chargers and something convenient to do as well. Their built in navigation showed them the way. (This was bmw, not Tesla.)
    - thatfrenchguy 2y ago
      I mean, you can use Tesla chargers with any car these days in the EU?
      - brnt 2y ago
        But they are a tiny minority of charging point, the market is quite diverse in Europe. And this whole setting up account, installing apps for each and every company, different in each and every country, is really off putting. I have no idea why they don't just use the kind of dumb payment terminals every unmanned carbohydrate station uses. Works with any card from any country all the time.
    - rootusrootus 2y ago
- elihu 2y ago
  Continuing to burn fossil fuels forever isn't really an option. At some point we'll effectively run out, but before then we'll have caused catastrophic climate change due to our CO2 emissions. Synthetic or plant-based fuels are plausible options, but synthetic fuels can't compare with battery EVs in terms of energy efficiency, and plant based fuels need crop land that's probably better used to grow food. Electric vehicles aren't a temporary fad. They're here to stay. Liquid fuels aren't going away either, but I expect eventually they'll be used mostly for military and aviation applications, not ground transportation.
  - amluto 2y ago
    > synthetic fuels can't compare with battery EVs in terms of energy efficiency, This is almost meaningless. If you are turning renewable energy sources into either synthetic fuel or grid power, then efficiency is irrelevant. What matters is cost (of the whole system, including distribution of the energy) and emissions (burning even carbon-neutral methane or hydrogen isn’t quite zero emission). There are startups working synthesizing fuels from air and solar energy, and they argue, fairly convincingly, that bypassing the entire electrical distribution network can more than make up for extremely low efficiency. Also, heavier vehicles likely emit more brake and tire dust than lighter vehicles, and a series hybrid can be much lighter than a long range BEV.
    - elihu 2y ago
      Of course efficiency matters, because electrical energy is a bottleneck resource. Renewables may be cheap, but they aren't free and we have a lot of other things we need that energy for. If you can make a car go 4 miles with 1kwh of electrical input, that's much better than a car that can got 2 or 3 miles with the same input. Multiply that by the ~1.5 billion cars/trucks in the world presently and that's a huge difference. Burning liquid fuel in a heat engine typically wastes about 2/3 of the chemical energy as heat. Hybrids do better, but there's only so much you can do. I don't know what the state of the art for synthesizing liquid fuel is, but I assume there's some significant energy loss there too. On the other hand, modern permanent-magnet electric motors can be around 95% efficient. Lithium ion batteries typically have coulombic efficiency better than 99%. Actual energy efficiency is a little less due to internal resistance (it takes a higher voltage to charge the battery than you get out when you drain it, so even if amp-hours in is almost equal to amp-hours out, watt hours might be a little different). Charging circuitry also tends to be pretty efficient. Battery-electric drive trains are already so close to optimal efficiency that there's very little that they can actually be improved on, and nothing else comes close. The tire dust microplastics thing is a real problem, but it's not that much worse for EVs than other cars. Brake dust is much less of an issue on BEVs and hybrids, due to regenerative braking. Personally I hope the idea of BEVs that haul around 800 pound batteries goes out of fashion (and it might if we could be bothered to electrify our major highways to make huge batteries largely unnecessary), and I also hope cars in general start to get smaller and less numerous. But I think cars are basically here to stay in some form, so they might as well be electric.

rsynnott 2y ago

Some buses also use these. Dublin Bus has a particularly disconcerting plugin hybrid variety; if it’s using the diesel engine, that runs constantly (so it’s noisier than a normal bus at rest) but if on battery, it’s silent. There are few things more unnerving than a double decker bus gliding along virtually noiselessly (their pure-electric buses, somehow, are noisier). Double-decker buses are supposed to sound like they might explode at any moment, like in the good old days. (/s, just in case; ye olde 20 tonne 1980s buses were extremely noisy, and it was not great.)

drmpeg 2y ago

The other problem it solves is the complex transmission required. Diesel-Hydraulic locomotives were built, but were not successful long term. The most famous is the Krauss-Maffei ML4000, built for the Southern Pacific railroad. https://en.wikipedia.org/wiki/Krauss-Maffei_ML_4000 https://en.wikipedia.org/wiki/Krauss-Maffei_ML_4000