7 ms·
which is the whole point of hybrids Part of the point, not the whole point. Regenerative breaking is absolutely a win; but there can also be a significant ben
by cperciva 1y ago
which is the whole point of hybrids
Part of the point, not the whole point. Regenerative breaking is absolutely a win; but there can also be a significant benefit from allowing the ICE to remain in the RPM "sweet spot" rather than moving around a larger range.
- unglaublich 1y agoThis is how diesel-electric locomotives work too.
- ben-schaaf 1y agoThey also use the electric motor(s) for braking, but instead of going into a battery it goes into a bank of resistors.
- ddeck 1y agoI think you meant capacitors. Resistors would just dissipate the energy as heat. edit: Thanks for the correction. They do indeed use resistors and just dump the energy as heat. Unfortunate. Hopefully this will change as supercaps continue to improve. Maxwell tech's modules are already used in light rail, and looks like some work towards smaller locomotives in Switzerland here: https://www.osti.gov/etdeweb/servlets/purl/20823697 https://www.osti.gov/etdeweb/servlets/purl/20823697
- ahartmetz 1y agoCapacitors have pitiful energy storage capacity. Resistors is correct, unfortunately.
- trained6446 1y agoNope, resistors. The energy is dumped as heat. Dynamic brake
- ben_w 1y agoTo add to the other comments: https://en.wikipedia.org/wiki/Dynamic_braking https://en.wikipedia.org/wiki/Dynamic_braking
- jnpnj 1y agoI heard about that long ago but couldn't find more, so IIUC chemically it's easier and more efficient to have a "one mode" combustion engine and let the electric engine deal with the variations, to the point that the reaction produces near no toxic byproducts, is that right ? I was wondering if there was research to keep improving that part. Even though it would help sustain the fossil fuel industry..
- Asmod4n 1y agoNissan hat the e-POWER system where a petrol engine is just used to recharge the battery of your electric car and nothing else. In theory they could run that petrol engine at the sweet spot where it produces the least amount of carbon emissions. i believe there is also a chinese company which is making such a car, their cars have nearly 1000 miles range.
- orwin 1y agoDiesel-electric engines in trains and tanks worked like that during WW2.
- p0w3n3d 1y agoAFAIK this is about engine efficiency. ICEs have highest momentum and efficiency sweet spot somewhere in the middle of available revs, which depends on the engine construction and was being altered by different mechanisms (like turbocharging and variable valve timing) but since the electric engine (I'm speaking of Toyota solution) is able to keep the ICE in the sweet spot with its eCVT, the engine can be simplified and even work on different combustion cycle (Atkinson's cycle)
- coryrc 1y ago> ICEs have highest momentum and efficiency sweet spot somewhere in the middle of available revs Close: they have the highest efficiency at about 90% of maximum torque for most of the RPM range. So if you want double the power, you want to be able to double the RPM; and if you want half the power, you want to be able to drop the RPMs in half. To pull this off, you either need a very quick shifting gearbox or some sort of CVT. This is also why automatic transmissions, despite being ~80% efficient versus ~95% manual transmissions, are not much worse on mileage. Because they can quickly switch between low RPM and higher RPM (first by torque converter lockup, second by switching gears).
- masklinn 1y agoAfaik that’s pure series hybrid and that’s almost non-existent in cars (outside of range extenders, not that there are that many of those). There are a handful but most hybrids are either parallel or series-parallel. I assume because the power range is so low that the conversion losses are way too noticeable compared to a mechanical drivetrain.
- federiconafria 1y agoThat's something I wish there had been more focus on, instead of focusing on massive heavy batteries, develop the hybrids further.
- ddeck 1y agoNot sure about the US, but the Japanese didn't stop focusing on hybrid development. More than half of all sales in Japan are hybrids, whereas electric is only a few percent [1]. Honda even recently announced that they're scaling back on electric to focus on hybrids: https://www.reuters.com/business/autos-transportation/japans-honda-scale-back-electric-vehicles-concentrate-hybrids-2025-05-20/ https://www.reuters.com/business/autos-transportation/japans... [1] https://www.bloomberg.com/news/articles/2023-12-19/hybrid-cars-will-be-the-majority-of-sales-in-japan-next-year https://www.bloomberg.com/news/articles/2023-12-19/hybrid-ca...
- matthewdgreen 1y agoYes but Honda seems to be doing this because they can’t make batteries. BYD can, ever cheaper, and they’re expanding their plug-in offerings much faster than Honda is scaling them back. I’m worried for Japanese car makers.
- dalyons 1y agoYep. Hybrids are a dead end, they’ll be obsolete in a few short years
- pkolaczk 1y ago
- pkolaczk 1y agoAnother part of the point is that you can pack a much smaller and more efficient ICE and then substitute the missing power and torque from electric motors when needed. Most cars are not used at max power all the time. You need max power only at short times when accelerating. With pure ICE there is the tradeoff - a bigger engine will get you more max power / max torque but is going to be less fuel efficient because of internal friction.
- mort96 1y agoAnd, you can make much lighter and lower range electric cars without all those heavy batteries, and boost the range with diesel when needed. Very attractive in principle. Most cars are not using their full range all the time, for a lot of people a 50 mile range car would be more than enough 98% of the time, but that remaining 2% means that people end up buying 200 mile range cars instead. But then, do you end up removing enough battery weight to offset the weight of a whole ICE?
- lotsofpulp 1y agoSmaller cars have always been available, but people have shown a preference for bigger cars where they can sit higher up, even though it costs them more.
- mort96 1y agoI'm not talking about size, I'm talking about range and weight. You can have a huge car or a smaller car, going from a 90kWh battery pack to a 30kWh battery pack is gonna have the same weight saving in both
- andrepd 1y agoMaybe they should be at least charged for the catastrophic externalities that that "preference" results in.
- eldaisfish 1y agodoes "preference" equate to endless, manipulative advertising from car manufacturers? Or, perhaps, the "preference" of higher profit margins from larger cars, pushing manufacturers to entirely abandon reasonably sized cars?
- throw0101d 1y ago> […] but there can also be a significant benefit from allowing the ICE to remain in the RPM "sweet spot" rather than moving around a larger range. Which is why I'm surprised electric cars with range extenders aren't a bigger thing: * https://en.wikipedia.org/wiki/Range_extender https://en.wikipedia.org/wiki/Range_extender Have the powertrain be all-electric, and have a battery pack, but for those with range anxiety have a small generator as an option that would go in the frunk (front truck). A (proverbial) small Honda EU2200i would be less maintenance than a traditional engine.
- recursive 1y agoRange anxiety seems to go away after your first week of EV driving.
- dboreham 1y agoIt isn't really "range" anxiety, rather "no charger available" anxiety. Today, if I run out of petrol|gasoline somewhere, even if I'm in the middle of nowhere and don't have a gas can, I can still recover from that situation within an hour or so (hitch a ride to the next gas station, buy gas can, fill with gas, hitch back to my vehicle). With an EV the density of fueling/charging locations is orders of magnitude lower than for gas, and if I end up discharged I'm looking at finding a flat bed truck, or perhaps a mobile high power generator. Disclosure: I own both kinds of vehicles.
- sokoloff 1y agoI'd say more that it evolves rather than goes away. We've had our BEV for over a decade and it's the car we tend to choose to drive for short distance errands. We like it by all means, but when one of us needs to take the hybrid car for a weekend or a local business trip, we still have to plan out to make sure the other can manage whatever we need to do with just the BEV. As dboreham says in the sibling comment, the range anxiety morphs into charger-availability anxiety. Even if I know a charger physically exists at my destination, if it's 45% or more of the range away, I still need to worry that it will be working, that my access will work, that it won't be occupied or blocked, etc. In nearly 40 years of driving, I almost never researched gasoline availability (through the Nevada desert and in Central America, I did). In a little over a decade of BEV driving, I've done a lot of EVSE (charger) researching.
- theshrike79 1y agoThis is the thing with good hybrids. The "gas pedal" becomes a "I want to go faster/slower" pedal, its position has zero impact on the RPM. As an anecdote: A security company I know only buys Toyota Hybrids for their guards just because of that. They have a habit of driving cars like they stole them and normal ICE cars break down from that kind of abuse. Hybrids won't let you abuse them, they pick the RPM and you deal with it. (They also swap the passenger seat for a plastic box because the guards threw heavy crap like safety boxes on it, wearing down the seat in months)
- vladvasiliu 1y agoDo all Toyotas do that? I'm pretty sure that my dad's Corolla will rev the engine when I press the gas if the engine is already running. I'm also surprised for the first few minutes when I drive it how little "engine braking" it has (my habit is from riding a big motorbike).
- theshrike79 1y agoDunno. My both Priuses did it and the company was specifically using the Yaris Hybrid. Both will rev on neutral, but when the gear selector is on Drive there is no link between the pedal and RPM.
- bonzini 1y agoAnd on Brake it's even the opposite: above a certain speed, you press the accelerator and the RPM decreases to remove engine braking.
- trklausss 1y agoDepends on the configuration. If they are equipped with a CVT+electric engine on the shaft, then that's the case: they rev to the sweet spot (which on gas engines is 4000-5000 rpm on acceleration? Depending on expected engine load I assume) and the speed is controlled by hydraulic force applied on the CVT. With other hybrids: depends on the generator they have installed, but it matches the consumption in amps by the engine in order to "go" if it is not directly coupled with the transmission, or they just downshift to accelerate with help of the electric engine. I am assuming a lot here: Toyotas (specially RAV4) mount CVTs among others, assuming pure electric generator by the ICE or coupled to it... So it depends a lot on specific configuration.
- SigmundA 1y agoMost hybrids on the road are parallel and have a mechanical connection to wheels and vary rpm as needed, although the CVT implementations may hold rpm due to gear ratios like any CVT hybrid or not. A direct mechanical connection is more efficient at highway cruise speeds than a mechanical->electric->mechanical conversion. The main win a gasoline hybrid has is in running the Atkinson cycle gaining efficiency while losing torque which the electric motor makes up. This brings the gasoline engine up into diesel efficiency territory. This is also why you don't really diesel hybrids, the engine is already very efficient but it is more expensive and heavier and hybrid adds more expense and weight.
- nixass 1y agoThat's the case only with CVT transmission
- pinko 1y agoAre there still a lot of hybrids without CVTs?
- eulers_secret 1y agoHyundai/Kia use a traditional 6-speed auto in their hybrids. I drive one, the engine stays at a few RPM stepping points during most driving (it likes ~1600RPM, ~2200RPM, and ~3600RPM). I had a Prius previously, and I like this different setup because it reduces "engine droning noise", which was terrible on the Prius. Though H/K have recently introduced a new hybrid system with a CVT, so maybe 2026 or 27 model years will be different. Since I'm only making one comment, I also want to say hybrid cars are better than ICE because there are fewer belt-driven accessories. Aircon in particular on an electric motor is a big improvement. Without the idling engine producing heat, hybrids are much nicer in hot stop-and-go conditions! Also my Prius made it its whole life (200k miles and ~20 years) without ever changing the brake pads... amazing!
- nixass 1y agoI'd say that the market is very fragmented. Toyota and Lexus, obviously, use eCVT in their cars. Honda is also in eCVT camp for most of their models but for example new CR-V has weird setup. It acts as an BEV until ~80-100kmh and then shifts completely to ICE with a single gear. While in EV mode the engine is constantly charging batteries. Then you have KIA and Hyundai with their dual clutch setup in all HEV and PHEV range.
- timc3 1y agoLots. BMW, Audi, Mercedes, Porsche, Volkswagen, Volvo for example. I find it a pity that Lexus uses CVTs as I would probably sell my BMW 330e and get a Lexus.
- HPsquared 1y agoDiesel engines with all their turbochargers, EGR, SCR, DPF etc equipment, work pretty well as part of a hybrid system. All that stuff works much better in steady-state operation. Diesel hybrid buses and trucks are much smoother and cleaner than non-hybrid.
- supportengineer 1y agoIn order to do this with a gas engine, it can be done but you need to completely mechanically decouple the gas engine from the drivetrain. The gas engine needs to do one thing and one thing only which is charge the battery. The gas engine has maximum efficiency at about 80% throttle.
- kube-system 1y agoThe efficiency of the entire system is more important than the efficiency of the engine itself. Charging the battery and then discharging it also incurs losses. Many series hybrids will prioritize generating electricity when some of it is also required to directly drive the motor. They usually don't sit around at low-load situations just generating electricity, unless SOC is low. > The gas engine has maximum efficiency at about 80% throttle. ICE efficiency varies in multiple dimensions based on load and RPM, and in a series hybrid, you have some ability to dynamically influence these... throttle would be one of those inputs.
- sliken 1y agoThere do exist serial hybrids where the engine produces electricity while maintaining the ideal RPM, and then is connected to a battery+electric motors. However in practice the vast majority of hybrids do not use this approach and have motors that vary RPM with road speed (depending of gearing of course). The common case of maintaining ideal RPM is the CVT, which most folks dislike, so much so that some models have a switch to pick how many fake gears you have to break up the boring drone of a constant RPM engine. BTW, the chevy bolt was advertised as a serial hybrid, right up to the day it shipped. I believe the most common serial hybrid today is an EV with a range extender.
- euroderf 1y ago> a significant benefit from allowing the ICE to remain in the RPM "sweet spot" rather than moving around a larger range. I remember buying plans from the Whole Earth News for such a car back around 1980. That was the selling point - keep the ICE running at an optimal point. I've not seen those same plans reproduced online.
- euroderf 1y agoAha! https://store.motherearthnews.com/products/hybrid-car-blueprint https://store.motherearthnews.com/products/hybrid-car-bluepr...