Surplus Internal Combustion Engine R&D Capacity: where should research go?

[shin_getter]

With the downsizing of traditional motor vehicle ICE demand, due to electrics and EU ICE Ban on the horizon, we are going to quickly see extra capacity of ICE engine development, which would take on projects that were not economically interesting in tighter times.

So what kind of development should the ICE field go into? Perhaps the ancient aero-engines can finally get a replacement?

If the short term excess in capacity is left unused, people are just going to retrain and facilities repurposed. Ultimately there is only a small time window to push next gen tech before the field slows due to descaling.

 

[gtg947h]

Perhaps the ancient aero-engines can finally get a replacement?

That would be my preference, as unrealistic as it is. Small marke size and high regulatory costs will doom that one...

 

[Calum Douglas]

Virtually all the improvements needed for current ICE used in light aircraft dont need any R&D at all, just application of what is already known perfectly well. Sadly, as the poster above alludes to, difficulties with the market of aero-engines means almost nobody bothers. RED being an exception.

Hybrid ICE cars will be in production until at least 2050 (and quite possibly beyond depending on what happens with supply logistics of E-fuels vs lithium/cobalt)

RED Aircraft – Home of the V12

red-aircraft.com

 

[gtg947h]

I kind of wonder what market that RED engine is aimed at. Any airframe that needs 500hp per engine was probably fitted with a turboprop a long time ago. If you were going to be making new light GA piston engines you'd be targeting more 150-300hp.

Yes, existing automotive technology would make for a wonderful new aviation engine; you still have to do the design and development work. I'd imagine you could probably start with a derivative of an existing auto engine (perhaps lightnening the block and removing unneeded accessories), but a lot (most?) of your technical work would come in integrating the propeller drive (chances are you'd need a reduction drive of some sort) and integrating a liquid-cooled engine into airframes designed for air-cooled opposed engines.

That's not even counting the stunningly massive paperwork/certification burden (which if you want to sell to anyone other than a small number of homebuilders, is a necessity). I don't think anyone outside the industry really understands how much additional cost and time and paperwork that adds.

Adding to that burden is that the FAA standards for electronic engine controls were written for the needs of jet engines going on airliners, and they're one-size-fits-all. You'd have to meet a standard that the existing carb-and-mag engines could never hope to achieve.

And all of that effort and money would have to be amortized across a few thousand units in the end. Remember, light GA production figures are in the ballpark of 1000 new airplanes/year (per GAMA reports), and homebuilt completions are around the same figure. I would figure that even a game-changing engine competitively priced with a horsepower-equivalent Lycoming/Continental would only sell a couple hundred units per year.


Unfortunately all of this will most likely never happen. There's not enough demand for new engines, at least at a price point that would fund them. I'm doing the best I can with the airplane I'm building, and fitting an SDS EFI package to a Lycoming. That gets me a lot of the EFI advantages while retaining most of the basic engine/airframe integration work.

 

[Hobbes]

Most of the technical work in converting an automotive engine to aviation use is in getting the reliability up.
Car engines spend most of their lives producing a small fraction of their maximum power, at 1/3 of their rev limit. Airplane engines spend their time far closer to max power. This means you have to modify the oil and water cooling systems to cope with increased loads. You have to change tolerances to keep the engine healthy in this new thermal environment.
Then add redundancy (two fuel systems, two ignition systems) and add fault tolerance.

 

[TomcatViP]

I kind of wonder what market that RED engine is aimed at. Any airframe that needs 500hp per engine was probably fitted with a turboprop a long time ago. If you were going to be making new light GA piston engines you'd be targeting more 150-300hp.

Yes, existing automotive technology would make for a wonderful new aviation engine; you still have to do the design and development work. I'd imagine you could probably start with a derivative of an existing auto engine (perhaps lightnening the block and removing unneeded accessories), but a lot (most?) of your technical work would come in integrating the propeller drive (chances are you'd need a reduction drive of some sort) and integrating a liquid-cooled engine into airframes designed for air-cooled opposed engines.

That's not even counting the stunningly massive paperwork/certification burden (which if you want to sell to anyone other than a small number of homebuilders, is a necessity). I don't think anyone outside the industry really understands how much additional cost and time and paperwork that adds.

Adding to that burden is that the FAA standards for electronic engine controls were written for the needs of jet engines going on airliners, and they're one-size-fits-all. You'd have to meet a standard that the existing carb-and-mag engines could never hope to achieve.

And all of that effort and money would have to be amortized across a few thousand units in the end. Remember, light GA production figures are in the ballpark of 1000 new airplanes/year (per GAMA reports), and homebuilt completions are around the same figure. I would figure that even a game-changing engine competitively priced with a horsepower-equivalent Lycoming/Continental would only sell a couple hundred units per year.


Unfortunately all of this will most likely never happen. There's not enough demand for new engines, at least at a price point that would fund them. I'm doing the best I can with the airplane I'm building, and fitting an SDS EFI package to a Lycoming. That gets me a lot of the EFI advantages while retaining most of the basic engine/airframe integration work.

In my opinion, given the cost of dev and certification and the large range of power that could suit the market, the main focus point is to have a parametric design and a scalable manufacturable product.

The second aspect is to increase altitude of flight, hence the reliance on safe and economic turbo and/or hybrid systems, what would be a must. Aircraft structure are becoming so light and reliable that a relative degree of pressurization is to reach the GA market pretty quickly.

Hence, IMOHO, wankel inspired turbo hybridized propulsion system could be the awnser.
A single design could be then easily scaled up (stacked in effect with just a custom design turbo per application) with a predictable reliability.

See what the UAV industry has done in the US.

 

[Fluff]

Sorry to be the prophet of doom, but automakers only do research because they are pushed by environmental rules, usually for cleaner emissions, hence diesel gate saga.

And they will already have moved everyone over to the battery side and a little to hydrogen research.

And as mentioned above, 'grandfather' rights and the risks of anything going wrong keep the old designs going in the small aircraft market. Just not enough demand, unless we are going to get personal VTOL - see the other thread.

 

[Calum Douglas]

Sorry to be the prophet of doom, but automakers only do research because they are pushed by environmental rules, usually for cleaner emissions, hence diesel gate saga.

And they will already have moved everyone over to the battery side and a little to hydrogen research.

And as mentioned above, 'grandfather' rights and the risks of anything going wrong keep the old designs going in the small aircraft market. Just not enough demand, unless we are going to get personal VTOL - see the other thread.

Have you ever worked in the engine mechanical design department of a major automotive manufacturer ?

I`ve worked in two, in two different countries; and whilst in recent years a massive amount of research is done on emissions, equally vast amounts are done on NVH, weight, cost, performance, economy and so on. Its simply not true at all that they only do what is required to pass legislation as far as R&D goes.

I dont know anyone doing hydrogen research at an OEM (they are, but not the friends I still have there).

Again, its also simply not true that all the R&D is moving to batteries. Hybrids are projected by most big makers as going to be needed until at least 2050 (despite what moronic lawmakers state). As such there will be a lot of engineers working on engines for decades to come.

 

[Fluff]

Sorry to be the prophet of doom, but automakers only do research because they are pushed by environmental rules, usually for cleaner emissions, hence diesel gate saga.

And they will already have moved everyone over to the battery side and a little to hydrogen research.

And as mentioned above, 'grandfather' rights and the risks of anything going wrong keep the old designs going in the small aircraft market. Just not enough demand, unless we are going to get personal VTOL - see the other thread.

Have you ever worked in the engine mechanical design department of a major automotive manufacturer ?

I`ve worked in two, in two different countries; and whilst in recent years a massive amount of research is done on emissions, equally vast amounts are done on NVH, weight, cost, performance, economy and so on. Its simply not true at all that they only do what is required to pass legislation as far as R&D goes.

I dont know anyone doing hydrogen research at an OEM (they are, but not the friends I still have there).

Again, its also simply not true that all the R&D is moving to batteries. Hybrids are projected by most big makers as going to be needed until at least 2050 (despite what moronic lawmakers state). As such there will be a lot of engineers working on engines for decades to come.

Sorry didnt realise this was a personal thread about you. I sit corrected.

Many of the european manufacturers have already stated no new diesel engines, only minor updates to existing designs.

'Everyone' is into hydrogen - in the UK some recent tenders have been issued for supply of infrastructure, i.e. for council fleets.

IMHO hybrids for cars are a half horse half donkey, too many parts, too many inefficiencies in real use, your either carrying an engine you dont need, in town, or a battery pack you dont need on the motorway. Battery and charging developments will wipe out hybrids, dont waste your money is my humble advice.

The reason current automakers are pushing hybrids is that its a quick update to an existing vehicle and engine, so keeps the capital investment down, until its time to develop a replacement, which will often be battery powered. Thats why we see a fairly random selection of battery vehicles, i.e. Vauxhall/Opel have a corsa, but no astra in BEV. VW have the purpose made ID3 and 4.

 

[gtg947h]

Most of the technical work in converting an automotive engine to aviation use is in getting the reliability up.
Car engines spend most of their lives producing a small fraction of their maximum power, at 1/3 of their rev limit. Airplane engines spend their time far closer to max power. This means you have to modify the oil and water cooling systems to cope with increased loads. You have to change tolerances to keep the engine healthy in this new thermal environment.
Then add redundancy (two fuel systems, two ignition systems) and add fault tolerance.

Oil and water cooling will have to be modified anyway as the arrangement of components in an aircraft will be very different than in a car. But as lots of test stand/dyno runs have shown, give a common production piston engine (airplane, auto, or otherwise) adequate cooling, proper lubrication, and proper fuel/spark delivery and they'll run damn near forever at high power. There's a common misconception that "car engines can't handle high power like airplane engines can", implying weakness in the "core" engine of block, crank, pistons, valve train.... but in reality, what kills auto conversions in reliability is the supporting systems--gearbox/reduction drive, ECU (use of an OEM one with unknown fail-safes/failure modes/programming), fuel and electrical supply, and the cooling/lubrication supply.

However, yes, some additional redundancy would be required, from a fault-tolerance and cert requirement standpoint.

The second aspect is to increase altitude of flight, hence the reliance on safe and economic turbo and/or hybrid systems, what would be a must. Aircraft structure are becoming so light and reliable that a relative degree of pressurization is to reach the GA market pretty quickly.

Pressurization sounds wonderful but it becomes a real pain from a maintenance, certification, and repair standpoint. There's a reason why so few light airplanes are pressurized. Besides, for the "mission" of most light aircraft (local-ish fun flying, or training) it's not required. All it does is add weight, complexity, cost, maintenance expenses, and fatigue concerns.

 

[TomcatViP]

@gtg947h : A lot of folks are using their a/c for routine flight longer than 200Nm. And this trend will increase (if you can commute by air in and out of the city (see on demand mobility), you'll want to commute farther than what's possible by car daily or, more probably, weekly).

 

[gtg947h]

@gtg947h : A lot of folks are using their a/c for routine flight longer than 200Nm. And this trend will increase (if you can commute by air in and out of the city (see on demand mobility), you'll want to commute farther than what's possible by car daily or, more probably, weekly).

Yes, people do sometimes travel with light airplanes. Relatively few people do it routinely. Very few people do so frequently enough and far enough that a pressurized airplane would be worth the additional expense. The interstate highway system and cheap commercial flights mostly put an end to that, except for people who do so because they want the experience of going in their own airplane. And I say this as one building an airplane to be used for travel (among other uses). But I look at all the people I know who are active private pilots, and almost all of them spend most ( >50%) of their time flying locally. Traveling more than an hour or so away is a "couple of times a year" event.

Light aircraft as we know them today are not a practical everyday traveling solution except when there's no real alternative. They're limited in where they can operate (still tied to airports, they don't solve the first/last mile problem), they're expensive (to purchase, insure, operate, and maintain), they require a significant time and money investment to get and stay qualified to operate, they're far more restricted by weather conditions than ground transportation or airlines. As the saying goes, "time to spare? Go by air"; your other alternatives are almost always going to be cheaper, safer, and more reliable.

I'm also really skeptical about this "urban air mobility" stuff. I don't think the efficiency and affordability is there for anyone but the special few to make use of it, I don't see the general public putting up with it (look at how spooled up some people get about ordinary light airplanes; what do you think they're going to do when giant-scale octacopters come blasting through downtown and dropping into the park in front of them?), I don't see how the FAA will integrate it all into the NAS without shafting traditional aviation (major vested interest here), and I don't see the FAA getting its head around certifying such a beast, especially something autonomous.

 

[TomcatViP]

I would agree mostly if we had that talk 20 years ago. You don't buy and fly a TBM700, a Panthera or a Piper 350 for touring your home airfield.

Nowadays, If you can afford such plane, you can afford to have your family settled far away from your job place and commute every w.e back home for example.

 

[Calum Douglas]

Sorry to be the prophet of doom, but automakers only do research because they are pushed by environmental rules, usually for cleaner emissions, hence diesel gate saga.

And they will already have moved everyone over to the battery side and a little to hydrogen research.

And as mentioned above, 'grandfather' rights and the risks of anything going wrong keep the old designs going in the small aircraft market. Just not enough demand, unless we are going to get personal VTOL - see the other thread.

Have you ever worked in the engine mechanical design department of a major automotive manufacturer ?

I`ve worked in two, in two different countries; and whilst in recent years a massive amount of research is done on emissions, equally vast amounts are done on NVH, weight, cost, performance, economy and so on. Its simply not true at all that they only do what is required to pass legislation as far as R&D goes.

I dont know anyone doing hydrogen research at an OEM (they are, but not the friends I still have there).

Again, its also simply not true that all the R&D is moving to batteries. Hybrids are projected by most big makers as going to be needed until at least 2050 (despite what moronic lawmakers state). As such there will be a lot of engineers working on engines for decades to come.

Sorry didnt realise this was a personal thread about you. I sit corrected.

Many of the european manufacturers have already stated no new diesel engines, only minor updates to existing designs.

'Everyone' is into hydrogen - in the UK some recent tenders have been issued for supply of infrastructure, i.e. for council fleets.

IMHO hybrids for cars are a half horse half donkey, too many parts, too many inefficiencies in real use, your either carrying an engine you dont need, in town, or a battery pack you dont need on the motorway. Battery and charging developments will wipe out hybrids, dont waste your money is my humble advice.

The reason current automakers are pushing hybrids is that its a quick update to an existing vehicle and engine, so keeps the capital investment down, until its time to develop a replacement, which will often be battery powered. Thats why we see a fairly random selection of battery vehicles, i.e. Vauxhall/Opel have a corsa, but no astra in BEV. VW have the purpose made ID3 and 4.

Despite your anger at the existence of Hybrids, they produce the least emissions for the least input. Because they do not require a huge
battery, and the engine can be maintained in its most optimal running areas.

A reasonably good scientific discussion of the facts is to be had here:

Watch Hybrid Future: Electric vs. Electrified Powertrains on PBS Wisconsin

Andrea Strzelec compares emissions of electric, internal combustion and hybrid engines.

pbswisconsin.org

You made the descision to post about a topic upon which it is far from clear that you know anything about, and therefore, it is not terribly
surprising that you find yourself being corrected by someone who does. This is called life, sadly - and we are all irked by it sometimes.

 

[Fluff]

Sorry to be the prophet of doom, but automakers only do research because they are pushed by environmental rules, usually for cleaner emissions, hence diesel gate saga.

And they will already have moved everyone over to the battery side and a little to hydrogen research.

And as mentioned above, 'grandfather' rights and the risks of anything going wrong keep the old designs going in the small aircraft market. Just not enough demand, unless we are going to get personal VTOL - see the other thread.

Have you ever worked in the engine mechanical design department of a major automotive manufacturer ?

I`ve worked in two, in two different countries; and whilst in recent years a massive amount of research is done on emissions, equally vast amounts are done on NVH, weight, cost, performance, economy and so on. Its simply not true at all that they only do what is required to pass legislation as far as R&D goes.

I dont know anyone doing hydrogen research at an OEM (they are, but not the friends I still have there).

Again, its also simply not true that all the R&D is moving to batteries. Hybrids are projected by most big makers as going to be needed until at least 2050 (despite what moronic lawmakers state). As such there will be a lot of engineers working on engines for decades to come.

Sorry didnt realise this was a personal thread about you. I sit corrected.

Many of the european manufacturers have already stated no new diesel engines, only minor updates to existing designs.

'Everyone' is into hydrogen - in the UK some recent tenders have been issued for supply of infrastructure, i.e. for council fleets.

IMHO hybrids for cars are a half horse half donkey, too many parts, too many inefficiencies in real use, your either carrying an engine you dont need, in town, or a battery pack you dont need on the motorway. Battery and charging developments will wipe out hybrids, dont waste your money is my humble advice.

The reason current automakers are pushing hybrids is that its a quick update to an existing vehicle and engine, so keeps the capital investment down, until its time to develop a replacement, which will often be battery powered. Thats why we see a fairly random selection of battery vehicles, i.e. Vauxhall/Opel have a corsa, but no astra in BEV. VW have the purpose made ID3 and 4.

Despite your anger at the existence of Hybrids, they produce the least emissions for the least input. Because they do not require a huge
battery, and the engine can be maintained in its most optimal running areas.

A reasonably good scientific discussion of the facts is to be had here:

Watch Hybrid Future: Electric vs. Electrified Powertrains on PBS Wisconsin

Andrea Strzelec compares emissions of electric, internal combustion and hybrid engines.

pbswisconsin.org

You made the descision to post about a topic upon which it is far from clear that you know anything about, and therefore, it is not terribly
surprising that you find yourself being corrected by someone who does. This is called life, sadly - and we are all irked by it sometimes.

oh I love a good correction from those much much better than I.

Shall we start on religion next?

Clearly you have never maintained a 10 year old car, nor seen a good car scrapped due to a warning light appearing at the annual test.

So your super duper design abilities, have not equipped you well for the future.

I can also spell decision, clearly english not your strong point. - dont know why you bother trying to use it.

 

[Arjen]

Gentlemen, might I suggest toning down the aggrieved note?

 

[Zoo Tycoon]

A green ammonia fuelled Napier Nomad II for a stationary engine.

Napier Nomad - Wikipedia

en.m.wikipedia.org

Near constant volume combustion, maximising the Carnot cycle efficiency, combined with low temperatures combustion for ultra ow NoX.

Hence a Zero CO2 emissions, ultra low NOX, with a very high “well to plug” conversion efficiency, taking advantage of green ammonia opportunities to offer the low cost means to transport/store energy capture at an optional location and release it in a high power density format at point of use.

 

[Fluff]

we seem to be somewhat off topic, plenty of topics for cars/hybrids.

Anyone got a view on actual aircraft - a slight tangent, once combustion engines are gone, be it 20 or 50 years, what will replace them - in aircraft?

 

[Fluff]

An green ammonia fuelled Napier Nomad II for a stationary engine.

Napier Nomad - Wikipedia

en.m.wikipedia.org

Near constant volume combustion, maximising the Carnot cycle efficiency, combined with low temperatures combustion for ultra ow NoX.

Hence a Zero CO2 emissions, ultra low NOX, with a very high “well to plug” conversion efficiency, taking advantage of green ammonia opportunities to offer the low cost means to transport/store energy capture at an optional location and release it in a high power density format at point of use.

Nice, would have gone in the Shackleton, that would have given some range boost.

 

[iverson]

<snip>
IMHO hybrids for cars are a half horse half donkey, too many parts, too many inefficiencies in real use, your either carrying an engine you dont need, in town, or a battery pack you dont need on the motorway. Battery and charging developments will wipe out hybrids, dont waste your money is my humble advice.

The reason current automakers are pushing hybrids is that its a quick update to an existing vehicle and engine, so keeps the capital investment down, until its time to develop a replacement,<snip>

Despite your anger at the existence of Hybrids, they produce the least emissions for the least input. Because they do not require a huge
battery, and the engine can be maintained in its most optimal running areas.<snip>

For what it is worth, I have owned Toyota hybrids since they first appeared in the US. All of them have delivered higher fuel efficiency than advertised and have required no maintenance above the usual oil and filter changes. The first one (a 2002) was recalled and repaired under warranty for a couple of things early on. But it ran to 140,000 miles before anything serious happened--a failed controller. It never had a brake job, due to the regenerative braking system. So the high parts count doesn't seem to hurt reliability or efficiency.

It is incorrect to say that the Prius, at least, is "a quick update to an existing vehicle and engine". The engine is an Atkinson-cycle type, rather than a Diesel- or Otto-cycle, and the transmission is infinitely variable. To me, the bodies all look unique to the Prius.

 

[Trident]

In Toyota-style hybrids, the IC engine is generally a pretty bare bones affair compared to a typical modern turbo, which helps in terms of cost and reliability (the parts count isn't actually that bad).

I kind of wonder what market that RED engine is aimed at. Any airframe that needs 500hp per engine was probably fitted with a turboprop a long time ago. If you were going to be making new light GA piston engines you'd be targeting more 150-300hp.

The Russian Altius-M UAV is actually a pretty perfect (if somewhat sinister) use case. I was struck by its claimed endurance of 48h (quite a lot better than the competing Reaper), but a back of the envelope comparison showed that with Diesels the difference is completely plausible. In an application where extreme endurance is required, the markedly better fuel consumption trumps the gain in engine weight (and possibly also number).

Yes, existing automotive technology would make for a wonderful new aviation engine; you still have to do the design and development work. I'd imagine you could probably start with a derivative of an existing auto engine (perhaps lightnening the block and removing unneeded accessories), but a lot (most?) of your technical work would come in integrating the propeller drive (chances are you'd need a reduction drive of some sort) and integrating a liquid-cooled engine into airframes designed for air-cooled opposed engines.

That's basically how the Thielert Centurion family came into being, they are modified Mercedes-Benz automotive Diesels.

 

[Grey Havoc]

The Russian Altius-M UAV is actually a pretty perfect (if somewhat sinister) use case. I was struck by its claimed endurance of 48h (quite a lot better than the competing Reaper), but a back of the envelope comparison showed that with Diesels the difference is completely plausible. In an application where extreme endurance is required, the markedly better fuel consumption trumps the gain in engine weight (and possibly also number).

On a side note, a lot of US R&D work on heavy fuel engines for UAVs through out the 2000s seemingly got tossed into the waste basket during the Obama administration (they may possibly have been trying to clear the way for using biofuels in the various services' UAV fleets as part of the very ill-fated initially USN centered biofuel initiative).

 

[iverson]

In Toyota-style hybrids, the IC engine is generally a pretty bare bones affair compared to a typical modern turbo, which helps in terms of cost and reliability (the parts count isn't actually that bad).Yes, existing automotive technology would make for a wonderful new aviation engine; you still have to do the design and development work. I'd imagine you could probably start with a derivative of an existing auto engine (perhaps lightnening the block and removing unneeded accessories), but a lot (most?) of your technical work would come in integrating the propeller drive (chances are you'd need a reduction drive of some sort) and integrating a liquid-cooled engine into airframes designed for air-cooled opposed engines

Well, the Prius engine does not have a turbocharger and intercooler. But it it is hardly bare bones. It still has everything that other Toyota four-cylinder engines have: twin cams, poppet valves, pistons, rings, fuel injection, 12-volt starting battery, etc. Plus it has the drive-train battery, an electric reverse motor, and, in the original configuration at least, two electric drive motors, one of which doubles as an alternator during breaking and coasting. One of the engineers that I used to work with called my Prius a "four-engined geek Ferrari".

I am not a mechanical engineer. But what follows is what I understand about these cars after owning three of them.

The Prius IC engine is not smaller than those in comparable vehicles: it has the same displacement as most Toyota four-cylinders (1500 cc if memory serves). The only thing that differentiates it is the Atkinson Cycle. In this system, the inlet valve is held open for part of the compression cycle. This makes the expansion cycle longer than the compression cycle, thus extracting more work from expansion than the engine expends on compression. This feature is part of the reason for the good fuel economy. The Atkinson cycle engine burns less fuel per cycle and is thus less powerful than an otherwise comparable Otto cycle engine. But it extracts more power from the fuel that it does burn.

My main point, though, is that the Prius is not a standard car with an electric motor bolted on. It is a carefully designed system that maximizes economy by recapturing energy that would be wasted in an ordinary car. The result is necessarily complex. But it works.

In general, IC engines in passenger cars have to be sized to provide enough power and torque for a required, minimum rate of acceleration. They deliver more power than the car can use under most operating conditions and thus weigh more and consume more fuel. The Prius IC engine is no different in this respect. But the Prius system lets the car make use of extra power that would otherwise go to waste and optimise fuel consumption over the course of a trip. The IC engine is integrated with an alternator, battery, and a control system. When the IC engine is running, the control system uses any excess power to charge the battery. When the battery stores enough power, the electric motor runs instead of the IC engine. The control system monitors the state of the powertrain as a whole and selects the optimum operating mode:

• When stopped, a Prius does not idle. If the battery is low, the IC engine runs until it is charged. Otherwise, the IC engine shuts down until you start up again, at which point the electric motor gets you moving while the engine restarts.
  
  
• During regenerative braking and while coasting, the IC engine shuts down while the alternator charges the battery. The Prius system essentially recaptures a percentage of the energy that the car expended during acceleration, rather than wasting the energy as heat in its brake rotors.
  
  
• When accelerating away from a stop, the IC engine and the electric motor work together. The electric motor delivers 100% torque and power at 0 rpm, where the IC engine has 0 of both. By the time the wheels are turning and the battery is draining, the IC engine is up to speed.
  
  (Priuses are not sports cars. But their performance can be surprising. A guy in a mid-life-crisis-yellow Corvette decided to cut my wife off at a stop light by outdragging her from the turn-only lane and cutting in front. His ostentatious throttle blipping annoyed my better half enough to make her forget her usually staid driving habits. When the light changed, she floored it. We were across the intersection before the Corvette could get moving and he stalled in the middle of the crossing.)

Getting back on topic, I am not sure what the future of the internal combustion engine and automobile/air transport may be. But I am sure that solutions won't be simple. We can't go on burning fossil fuel. Had we accepted that 50 years ago, there might have been simple solutions. But now, every approach will likely involve complex trade-offs, compromises, and sacrifices that we haven't imagined yet. The Prius is, hopefully, a harbinger of the engineering spirit that will accept the sacrifices, make the trades, and come up with harmonious, practical, if complex results.

 

[Hobbes]

The Prius has another trick: the electric motors can be used to keep the ICE in the rev range for which it is optimized, making the ICE more efficient.

 

[Trident]

Well, the Prius engine does not have a turbocharger and intercooler.

Sure, a petrol turbo is arguably simpler over all, but you only get what you pay for - in terms of efficiency the only relevant competition here is a modern turbo-diesel. In which case the charge air cooler is liable to be liquid-coolant and the turbocharger to have at least a variable-geometry turbine or possibly even be two-stage. Add the more elaborate exhaust aftertreatment system with EGR (almost certainly cooled, possibly HP *and* LP), a particulate filter, SCR *and* NSC... and suddenly the Prius doesn't look so bad any more. Electric motors aren't exactly the most complex of mechanical contraptions, either.

My main point, though, is that the Prius is not a standard car with an electric motor bolted on.

I did not say it was!