[Closed] Cars with a petrol/diesel engine AND an electric motor

I think the idea is that an internal combustion engine can be made to work as efficiently as it can (...another topic of discussion...) at a set speed/load, which isn't what you do currently accelerating through the gears/braking/ etc etc. So overall, an IC engine working at constant load charging batteries and running and electric drivetrain may still be more efficient overall - but is not optimal, just a bridging technology with the infrastructure we currently have.

EDIT: A similar technology is used for ships, whereby an industrial gas turbine which is relatively efficient at a given load/speed is used to drive a generator, which feeds an electric motor. There are other issues here around packaging/control of the ship/etc etc, but overall thermal efficiency is a driver too.

Ok. Here's the short answer, let me know if you want the long one 🙂

In most 'hybrid' cars, having a petrol engine coupled with an electric motor allows the petrol engine to be used only when it's most efficient to do so. So:

1. When you are going very slowly, it's on electric only.
2. When you are going at a reasonable pace, you can siphon off energy that would be wasted and put it into the battery
3. When you are cruising, the electric motor doesn't contribute
4. When you boot it, the electric motor provides extra power
5. When you brake, the motor works as a generator and recharges the battery some more.

You don't have to add electricity from a power station - all the electricity to charge the battery gets recovered from places where it's wasted in a normal car.

Bristolbiker is talking about series hybrids (as opposed to parallel hybrids which are in most hybrid cars), which are used in trains, boats and things, for a variety of reasons.

Having just bought a used car and looked into this, the thing that gets me is the fact that the quoted fuel economy for something like a Prius is still worse than a modern diesel engine.

Does rather beg the question, what's the point?

Well the older model Prius came out in 2003. It's good for 60mpg in normal driving, and is larger than a Golf. It's also petrol, which is cleaner and often cheaper. At the time I got mine, in 2006, nothing of its size had anything like its CO2 emissions and could not match consumption either; only tiny little Aygos etc could come close.

Now, you can get bluemotion/eco-tec diesels and so on which, on paper, are more economical. Still only a few of them are lower CO2 emissions than the OLDER mkII Prius.

However the new mkIII Prius gets 70+ mpg, is bigger still, faster and has the lowest CO2 emissions of ANY car, even the tiny ones, and is more economical than most of the bluemotion specials, not to mention more powerful. And being petrol again it's way way cleaner on other emissions like NOx (responsible for smog and poor air quality) and smoke.

That's the point 🙂

I'd have a Volvo V50 drive thanks. 70+mpg also, less environmentally harmful to manufacture than a Prius, and more useful space in the car. Probably uses less consumables such as tyres and brake pads etc because of the more reasonable weight. Volvos last a long time as well, which helps.

To me the Prius is cynical solution aimed at those who don't fully think it through. Sorry molgrips. If you really care that much cycle to the shops and run a diesel super mini.

Yeah but the prius looks ****ing minging! 😉

Molgrips - ok, I stand corrected 😳 🙂

Samuri - you're not wrong, although the latest model is a little better.

has the lowest CO2 emissions of ANY car, even the tiny ones, and is more economical than most of the bluemotion specials

If it has the lowest CO2 emissions, wouldn't that make it more economical than all other cars at least in fuel terms?

It would if the test used to determine CO2 emissions bore any relation to real world driving. The importance of these test results for marketing also cause ECUs to be programmed to give the best possible test results as opposed to the best real world compromise,, which is why chipped cars can do the seemingly impossible and be both faster and more efficient in reality!

I was travelling in a Prius a little while back, and it was very quiet and very comfortable. Very smooth acceleration at lower speeds, and felt quite different to other cars. I think if they used less electronic gizmos they might be even more efficient. Personally, I feel that the environmental side of things is far more important than fuel economy, but of course in the real world, it's the latter which is the crucial factor.

the thing that gets me is the fact that the quoted fuel economy for something like a Prius is still worse than a modern diesel engine

It depends whether the figures can be compared like for like, if you take the maximum MPG a petrol or diesel car can acheive it only achieves that figure at a speeds and in circumstances that people rarely drive in - faster than you can drive around town, slower than you drive on motorways, with no junctions, no roundabouts no braking or changing gears. So apart from being stuck behind a truck up the A9 between Perth and Inverness its a fantasy value.

The advantage, I would hope, of combining elec and petrol is that you'll travel in an optimum, economical manner for more of of the circumstances of your journey. So in use, rather than in marketing material, something like a Prius should out perform a comparably size car.

The other advantage of the combination is that we are at a very early stage in the transition away from fossil fuels for road travel (if indeed we ever make that transition) and at present we don't have either the driving habits, (in terms of range) or the infrastructure (in terms of charging facilities at home and one the road) that would make drivers feel happy to set off on a journey on battery power alone.

http://www.cafepharma.com/boards/showthread.php?t=206826

Probably uses less consumables such as tyres and brake pads etc because of the more reasonable weight

Haha, prime piece of forum bullsh*t there, well done 🙂 Prius weighs about the same as a V50, plus it uses regenerative braking which means the brake pads can last for over 100k miles.

From my own experience, I get between 58 and 62mpg from my mkII Prius in real world driving in the summertime. That includes driving around town and long motorway trips down the M4, all done at the speed limit.

Sorry molgrips. If you really care that much cycle to the shops

What on earth makes you think I don't cycle (or walk) to the shops? You are assuming that because I drive a Prius I think I'm some kind of fabulous eco-warrior who's better than everyone else? No, really, I just wanted a decent sized economical car. That's not a bad thing to want is it? Didn't really fancy shoving my kids and relatives into the back of a supermini. Should I have bought something LESS economical to please you?

If it has the lowest CO2 emissions, wouldn't that make it more economical than all other cars at least in fuel terms?

It is by far the most economical petrol car. All other cars that come close are diesel, and a litre of diesel produces more CO2 and a lot more other pollutants than a litre of petrol. Which is why it's so clean - 15% less CO2 than waverider's V50 and none of that nasty NOx. But that's still a great car, I'd happily drive one. Bit slow too with only 109bhp though as opposed to 138bhp in the new Prius 🙂

I dunno why Priuses get such stick. Nice economical car - what's the problem?

porter-jamie - that "study" is widely known to be utter b*llocks 🙂

which bit? the battery doing laps of the world?

I very much doubt if any of the Prius' I see get 70 - they're always flying past me at about 80-90 on the motorway 😉

I think the reason Prius's get such stick is that they are promoted as being really green, which they are pretty good at their end use, but surely greenness should take into account the whole of the vehicle's life such as the pollution from nickel mining shipping the nickel for processing by ship, shipping the processed materials back etc. all of which are not green. As on Top Gears demo you can drive an M3 as economically as a Prius. I like the Prius down the road from me. It doesn't have to pay any congestion charge but it permanently has a roof rack fitted but doesn't carry anything and gets thrashed so isn't economical.
I also don't like all this focus on CO2 emissions because it has sod all to do with how much mileage people travel. I did 3000 miles in my car last year. I know it's not the most environmentally friendly car but it causes way less pollution than a Prius or whatever doing normal annual mileage. I don't see why they don't just scrap road tax etc. and put it straight on the cost of fuel. If you drive an uneconomical car or drive more miles it costs you more - or is that just too simple a solution?

there are 2 points in a prius

they have a very green image. this is good for smug people, and also companies wanting to portray a green image

they are much more economical than petrol cars. this is great in places where it's difficult to run a diesel car, for emissions reasons. Ie America and Japan (2 massive markets)

diesel hybrids will obviously be a better choice when they're available. Pug reconned they would be doing one of the rcz that has a total of 200bhp (1.6 diesel iirc) and does 99co2s, so is cheap to tax etc. Seems like a great combo to me

the newer generation (not out here, yet) such as the chevvy volt use a petrol engine, but it has no direct drive to the wheels - ie it only drives a generator which only powers a battery which powers a motor which drives the wheels. This sounds inefficient, but eliminates the drivetrain (30% loss normally) and means the motor can be run at a single rev range (ie 1600rpm the whole time), thus be smaller (50bhp), simpler and cheaper. lotus are doing one of these (called a range extender). obviously it has limitations, ie can't cruise at high speeds for a long time, but for general driving they look pretty good

but surely greenness should take into account the whole of the vehicle's life such as the pollution from nickel mining shipping the nickel for processing by ship, shipping the processed materials back etc. all of which are not green

Well there is a lot more to it than that. Apparently most nickel is recycled, since it's as easy to recycle it as it is to refine the ore. Also a Prius weighs 200kg less than say a Golf, battery included. So that extra 200kg of gubbins has to be manufactured somewhere, shipped somewhere, the raw materials have to be mined and refined just the same.

Also the factory in Japan that makes them is something like 70% solar powered; uses water from an adjacent river and puts it back in cleaner than it comes out; and sends nothing to landfill.

As on Top Gears demo you can drive an M3 as economically as a Prius

What does that tell you? Nothing.

I did 3000 miles in my car last year. I know it's not the most environmentally friendly car but it causes way less pollution than a Prius or whatever doing normal annual mileage.

A valid point, but you are missing the real one somewhat. You could be doing 3000 miles a year in an economical car and save even more CO2 emissions 🙂 We all need to reduce as much as possible - we aren't working to a set CO2 alloawnce.

Re the 'road tax': It's a pretty small component of the total cost of car ownership, but it has a big psychological impact - because you tend to forget about it then all of a sudden bang, it comes out of one of your pay cheques. I had my tracking done the other day, and the mechanic was absolutely stunned that I only paid £15/year for my road tax, compared to his £150 or whatever for 6 months in his Civic Type R. Never mind that I was getting maybe double the fuel economy - he didn't seem to care about that, despite most likely costing him a lot more over a year.

Diesel hybrids could be good, but as far as I can tell the gains would be less. When driving a petrol car at low revs, you have to throttle the intake to reduce engine speed, which is wasteful. In a diesel, you only inject the fuel you need which is not wasteful. In a petrol hybrid, rather than throttle the engine you just divert energy to the battery, and when it gets full you just cut the engine. So petrol hybrids remove some of the advantages of diesel over petrol, and consequently I reckon the percentage gain would be less for a diesel hybrid.

The Chevy Volt is a great idea but it's built on more advanced battery technology that they are apparently having trouble with. It's an electric car with a 40 mile range that has a petrol genny to top it up. And you can plug it in. So the idea is that you drive it purely electric all the time unless you need to do a long journey, whereupon it runs on petrol and (supposedly) has the performance of and somewhat better economy than a normal car. It does not have mechanical drivetrain losses, but it does have electrical losses, so the absence of a gearbox is not really a factor.

Very nice idea tho. This set-up (series hybrid, like trains) would definitely benefit from being diesel I think.

FWIW I'd have been very attracted to a Volvo DRIVe or a VW Bluemotion car if they were out when I was splashing cash on a Prius. And I'd have bought one last year instead of a normal TDI Passat if there had been any second hand.

From my own experience, I get between 58 and 62mpg from my mkII Prius in real world driving in the summertime. That includes driving around town and long motorway trips down the M4, all done at the speed limit.

Prius is a green wash. The greenest car would be small light and longlasting. Aygo or wagonr or similar. Small engine and light body

the prius exists because of an american marketplace where car with zero emission in cities are favoured. Total lifetime environmental cost they are not good. all that extra lithium of whatever in the batteries, they are big and heavy, most of the High MPG comes from the easy rolling tyres and low areo drag.

Edit - a lot is guesswork because toyota wioll not release any info on the batteries - why?

I'm glad you joined in, this is an interesting subject.

What does this mean?

2. When you are going at a reasonable pace, you can siphon off energy that would be wasted and put it into the battery

What is NOx? I thought diesels were cleaner than petrol?

What we really need to do is change our driving habits and not do what I have just done (in my defence it is something I do only very rarely) and that is drive my monster car the few miles to the off licence so as to catch it before it closed.

I'd have a Volvo V50 drive thanks. 70+mpg also, less environmentally harmful to manufacture than a Prius, and more useful space in the car.

hmmm I doubt that. Official figures for a volvo V50 put the extra urban mpg at 50.1 [url= http://www.autotrader.co.uk/articles/2006/08/cars/volvo/v50/volvo-v50-d5-se-sport-car-review ]linky[/url]. The same site give the prius mpg at 76.4. I'd be interested to know where you get figures of 70+mpg for the volvo.

I think that TJs comment on green washing whilst valid is a bit of an over simplification. This combination of technology had not been achieved before toyota did it with this car. Whist there is an element of green washing someone had to do this first and what if the small cars that you mention were to get this sort of technology too? It certainly isn't the single answer to improving the efficiency of cars but to dismiss it out of hand like that seems a little harsh.

Gone fishin - its the truth tho. Oversimplified it may be but its a fundamental truth. Car amnufacturers won't make a green car - its not good business to make small light cheap car that lasts a longh time

a fiat panda is better than a prius because of the small amount of materials in it.

The prius is about zero emissions in cities and about salving peoples conscience Half the weight of it and use a 500 cc engine and you get closer to the mark.

total lifetime environmental penalty is the key thing - and the prius is bad on that because of the batteries. Toyota will not release any info on the batteries life and recycling - why - because the numbers are rubbish is my guess. they certainly will not last 20 yrs

Volvos are good on this because they last a long time. a significant amount of the environmental penalty is in the manufacture and disposal of cars.

lets put this another way - if petrol was £50 a gallon how long until 100+ mpg cars? if road tax was per kg and escalated rapidly after 500 kg how long till the 500 kg car?

I agree with TJ.. The prius is a bit greenwashy. After maybe 15 years and 200k+ miles it might offset the extra production costs and environmental impacts, but how many are likely to see that?
My ideal hybrid would be a small diesel with a flywheel energy storage system. Light, simple and no dirty metal batteries.

This bit doesn't make sense to me.
[i]"When driving a petrol car at low revs, you have to throttle the intake to reduce engine speed, which is wasteful. In a diesel, you only inject the fuel you need which is not wasteful."[/i]
Are you saying that a petrol engine is most efficient at full throttle ?

Are you saying that a petrol engine is most efficient at full throttle ?

Official figures for a volvo V50 put the extra urban mpg at 50.1 linky... I'd be interested to know where you get figures of 70+mpg for the volvo."

Homework: 0/10 - must try harder 😉

[url= http://www.vcacarfueldata.org.uk/search/vehicleDetails.asp?id=23038 ]"Linky"[/url]

the prius exists because of an american marketplace where car with zero emission in cities are favoured

I'm pretty sure that it's also partly because diesel is a dirtier fuel in the US. I know a couple of years ago modern 'clean' diesels like we have in Europe weren't possible over there because of the fuel quality.

I think electric/part electric cars are a good thing, they teach pedestrians to look rather than just listen and that's got to be good for cyclists.

I'd never have a diesel coz they're stinky and dirty, and I've followed too many modern ones belching black smoke at every gear change.

[i]if road tax was per kg and escalated rapidly after 500 kg how long till the 500 kg car?[/i]

TJ, I'm surprized you wrote that. Crash preformance of the 500Kg car is ??...Wouldn't the Mondeo already be 500Kg, if it were possible ?, the Manuf would love that.
Modern car weight is not a simple issue. On the one hand, Maunfs want to produce a lighter car, on the other hand, the customer demands more in their cars, not withstanding the crash preformance demanded by authorities in any particular market.

Molgrips, you work in Auto ?.

As I've written before, battery powered cars as we know them today, are not the final solution. Far from it.

GM microbes recycling waste into alcohol based fuels is one credible goal.
As an interim phase, plant material in the form of arable crops, is used to produce fuel, although ultimately, I'd like to see a move away from that. Which is starting to happen, espically at the testing stages.
(Don't even think about whinging about starving masses, I'm not even going to entertain remarks about that cr4p)
Unfortunately, any benefit from producing loads of nigh-on carbon neutral fuel, is p155ed away by producing it using conventionally powered agricultural machinery, then transporting it by conventionally powered vehicles/shipping.

Even then, I wouldn't suggest that carbon neutral should be where it stops.

For the next 50 years, heading towards producing a liquid type fuel to run engines in a similar format to todays motors, is the best we could reasonably hope for, imo, when stepping back and trying to appreciate/consider the [i]Big Picture[/i].

The Honda clarity ws along the right lines, but for the fact it was hydrogen powered.
Again, I have explained why the Hydrogen powered car isn't a real-world solution.

So you're telling me that a Prius is more environmentally friendly over its life than a Series III Landy running on chip fat?

surely it depends where you drive it?
A prius in city conditions is using 0 petrol. Beat that in your conventional car.

solo - a light car uses less energy to make it, to accelerate it and to recycle it.

Manufacturers have no incentive to make green cars - and of course a 500 kg car could be made safe. How heavy is a smart? Whats its Ncap rating? ( well maybe 500 kg is a bit light but you get my point)

It would have to lose all the gadgets so beloved of modern motorists tho. Become a much simpler and more basic vehicle. Think 2cv not Mondeo or a modern cyclocar

Unless you reduce the amount of materials in a car any "greening" remains greenwash

Biofuels from crops can never work - there simply is not enough arable land to make enough fuel

Basspine - but it needs to get tha energy from somewhere - so either the petrol engine has to start up when the battery runs flat or the petrol engine works harder to recharge the batteries once out of town

TJ the energy always has to come from somewhere! sunlight eventually if you look far enough back

I thought a prius charged its battery from braking not from the engine working harder?

Wouldn't the Mondeo already be 500Kg, if it were possible ?, the Manuf would love that.

Lightweight technologies exist, the problem is cost. Car manufacturers are proft-driven. Weights of replacement models have fallen in recent years, driven by demand for improved economy/efficiency. However, these changes have largely been achieved by removing 'bloat' from earlier lazy/sloppy design and manufacturing.

Mass-market manufacturers aren't going to push into new lightweight technologies (with significant R+D and manufacturing investment and higher materials cost) without a motivation - whether that's consumer 'pull' or government/fiscal 'push'.

A "greener" car also needs to be long lasting and infinitely repairable - again not in the manufacturers interests.

Think 2cv or similar cylocar. Small engine ( 500 cc or less) Simple, ( no electric windows etc) Galvanised and plastic construction, foams to give crash resistance, modular replaceable components.

NO car manufacturer will do this tho as it has no profit in it.

ebygomm - both. It can't recharge for ever from regenerative braking there will always be losses so at some point the petrol engine needs to change the battery

2CV was 600cc 😉

The best thing to do is service and look after your current car. Any new car is a HUGE hit on the environment and the government scrappage scheme is a horrendous abuse of the publics attempts to be green.

Agree with TJ - Toyota (who have recently shown they aren't exactly the most transparent of companies) don't publish figures on battery manufacture - the Prius is made all over the World so just shipping the parts costs the earth a fortune. Add the nasty chemicals used (which takes enormous resources to extract) and you have the car equivalent of the apparently well behaved kid packing a gun in his pocket.

My bro-in-law has a bi-fuel Volvo - horrible gutless thing but also basically mono fuel - they only ever use petrol in it.

You're better off hanging onto a V8 Range Rover for 25 years and really looking after it than buying a new car to try and ease your guilt.

Think 2cv or similar cylocar. Small engine ( 500 cc or less) Simple, ( no electric windows etc) Galvanised and plastic construction, foams to give crash resistance, modular replaceable components.

...which, in turn, requires a ground-up re-think of car design, rather than trying to 'improve' what we have. Similar to the way Gordon Murray is attempting to go with the T25.

One big problem is likely to be consumer acceptance of something radically different...

clubber - Member

2CV was 600cc

375 cc in the original one IIRC -. I have been in a 425 cc one.

My view is the incentive needs to be done thru taxation. Make petrol very much more expensive - £25+ per gallon at todays prices( ratchet it up over 20 yrs) and also tax on weight and physical size - with a low level for small and light and rapidly escalating as cars get bigger and heavier - again phased in over 20 yrs

I say again - if petrol was £25 a gallon how long until we had 100 mpg cars?

The engine used to drive a genny to power the electric motors is pretty much how the large diesel-electric trains worked:

http://en.wikipedia.org/wiki/Diesel_locomotive#Diesel-electric

And taking the long-lasting subject further, how many more years before my 12 year old 535i becomes 'green'? 😉

[i]and of course a 500 kg car could be made safe. How heavy is a smart? Whats its Ncap rating? ( well maybe 500 kg is a bit light but you get my point)[/i]

No, lets not generalise like that. How many people have a use for a Smart car ?. There are more Mondeos on the road than Smart two seaters.
This inidicates that there is a size-of-vehicle demand.

[i]It would have to lose all the gadgets so beloved of modern motorists tho[/i]
Agreed. But you sell someone today, a car with no aircon, manual windows, etc.....
Again, customer driven, don't bash the manufs.

[i]Unless you reduce the amount of materials in a car any "greening" remains greenwash[/i]
Agreed ^^^

[i]Biofuels from crops can never work - there simply is not enough arable land to make enough fuel[/i]
Very limited thinking here. Ocean testing using ocean based plants is already taking place... 😉

[i]Lightweight technologies exist, the problem is cost.[/i]
Exactly. Carbon-monocoqe mondeo anyone ?.
just dont mention the resin/recycle-ability of CFblah, blah***

[i]Car manufacturers are proft-driven[/i]
Yes, as well as car prices are market driven.
£60,000, CF Aygo, anyone, anyone ?

[i]again not in the manufacturers interests[/i]
Wrong again. Manufs bring new cars as a practical function of tool wear and [b]customer/market demand for [i]new[/i] cars.[/b]
Production tools wear-out. When they do, you either re-produce those tools and keep knocking out the same car for more and more money, like whos going to pay more for the same car/10 year old design(workforce wage demands/inflation). Or, faced with the prospect of ordering new tooling, you produce a new car, which can incorporate new design features for...safety and economy.
Knocking-out the same car for 300 years isn't a flyer, imo.

[i]NO car manufacturer will do this tho as it has no profit in it.[/i]
Again, not correct, please, please understand Manufs have to respond to what WE buy and what Govs suggest they would like to have offered for sale. Blamming the Manufs alone, isn't really addressing the issue.

Lots of carrots and sticks are required, but Joe Public has a hand in this too. Shouldn't the new-car buying public get-real too ?.
BMW wouldn't shift a single X5, if people decided that they we're going to descriminate against stupidly sized soft-roaders.
And while I'm here. WTF is that BMW monster that looks part X5 and part coupe.
Imo, that car really takes the P155 out of trying to address car emssions/fossil fuel consuption.

br - thats a serial hybrid propulsion system, which molgrips kindly pointed out as I went slightly off-topic in post #1 😉 That has as much to do with power delivery characteristics (electric: peak torque at zero revs, commpared to IC: peak torque at nearly peak revs) as efficiency.

£25+ per gallon at todays prices( ratchet it up over 20 yrs)

I think we've done the car is bad/what will happen when the oil runs out to death before and is drifitng off of the OP's more technical question. As an alternative to hybrid electric, BMW are looking at adding a a medium pressure heat recovery system from the coolant system and exhaust to power a steam turbine directly attached to the crank shaft. Adds a further 10/15% to the overall thermal efficieny of the engine. Planned to be added to road cars in the next 5 years (IIRC) if development contiunes on track.....

That would be the monumentally ugly BMW X6 then.

Truly a pointless car that has but a single purpose in life: to tell people that they wanted a BMW _AND_ a 4x4, but have no taste and no ability to understand the fundamental role of a 4x4.

[i]As an alternative to hybrid electric, BMW are looking at adding a a medium pressure heat recovery system from the coolant system and exhaust to power a steam turbine directly attached to the crank shaft. Adds a further 10/15% to the overall thermal efficieny of the engine. Planned to be added to road cars in the next 5 years (IIRC) if development contiunes on track..... [/i]

I'd love to see that work in -30 degrees, +40 degrees.

Where does the steam come from ?.

From waste heat from the engine.

Errr, yeah, heat is required for steam....What else though...

Edit:
That X6 hacks me off largely. What it says is
"Ha, I'm looking as if I'm rich, and whether I am or not, I'm going to make no attempt to contribute to a cleaner enviro.
Instead I'm going to let you do that while I tank around, in my tank"

Yeah, I do not like those cars, and I'm not sure I'd like the owner either.

Well obviously...

Where does the steam come from

Hot water from the coolant (with the water jacket extended to cover any remotely hot part of the block, plus INSULATION around the engine), further heated by a water jacket all the way along the exhaust system. You easily get >100 deg from the current cooling system, so by presurising it a bit more and stalling the flow longer around the engine (the complete opposite of what a current cooling system does - i.e. remove heat as effiicently as possible) you can get enough energy to do useful work.

This inidicates that there is a size-of-vehicle demand.

Yes, but...

Shouldn't the new-car buying public get-real too ?

How many 4/5/6/7 seat cars are regularly used with more than 2 occupants?

Clearly this is a difficult one to solve as many people buy bigger cars because they need the extra space [i]sometimes[/i]. However, the point about efficiency/benefits of much smaller cars could be relevant in many cases.

The Toyota iQ and T25 look at ways of using the space inside a small car more effectively (both having 3 seat potential).

So, clubber, steam turbine in a car. Wheres the water coming from ?
Its quite heavy stuff too, IIRC.

🙄

Yes, I understand that thanks. Doesn't mean it can't be made to work. Look up the specifics of what BMW are doing them post specific criticisms please rather than just vague 'it won't work'.

Not that I like Beamers.

Wouldn't change-of-state in the water reduce its cooling effect.

Engine block water is pressurized to increase boiling point, in order to allow the water to carry more heat away from the hot-bits.

Allowing steam to occur in the system ?, wouldn't that reduce system pressure ?.

Also, engine coolant isn't just water, boiling it would cause issues.

Generally, I've yet to be convinced on that one.

I wouldn't have an issue with a 7 seater carrying one person if the vehicle ran on a [b]fuel[/b] which had much less enviro impact, or better, none at all, and was infinately reproduceable, cleanly.

Otherwise, Bus for the family, Aygos for all license holders of the house ?

Taxation ?, whos that going to hurt the most ?, those who can least afford it.

Anyone who suggests the £25 gallon, doesn't own or have to re-fuel a car, and so by that fact, has to have that comment ignored.

Allowing steam to occur in the system ?, wouldn't that reduce system pressure ?.

Also, engine coolant isn't just water, boiling it would cause issues

You don't boil water it in the cooling system - as you say, in current engines it is pressurised so it doesn't. By throttling the high pressure temp liquid back into ambient air, you get wet steam to drive the turbine. As energy is extracted from the steam it cools to liquid water again and is pumped back into the cooling circuit. The technology isn't new, but the application is.

Again, this is drifting off-topic somewhat - this was meant simply as an example of an alternative 'hybrid' technology and the fact that there is now an economic and political/marketing driver to invest in bringing these technologies to market.... but not yet a business case to move away from oil based fuels.

I thought of this heat recovery system a while back 🙂

It's worth noting that once you have a hybrid electric system, you could scavenge electrical energy from all sorts of places. A steam turbine generator system driven from a heat exchanger in the exhaust for one, and the coolant for another. You could also have inductive dampers on the suspension generating current. Or, for a fairly straightforward upgrade you could stick a generator on the end of a turbo and generate leccy from the engine waste heat that way. Loads of options.

TJ - you're being a bit silly to be recommending tiny cars as a replacement for big cars. Of course it's more economical to drive a tiny car. But today, people want crash protection, comfort and a car big enough to carry a family around in. We upgraded from a Seat Ibiza to the Prius because we were going to want to carry adult passengers about in relative comfort.

I'd love a hybrid Yaris, if they made one. Unfortunately I can't afford three or four cars, one for every possible eventuality. If I could though, I would! (and keep them for a long time too, before anyone starts going on about changing cars every three years as if all eco-car owners have to do that).

You're better off hanging onto a V8 Range Rover for 25 years and really looking after it than buying a new car to try and ease your guilt.

Mat - what if your old range rover has just died? This is the point. No-one's advocating changing your car all the time, what we are advocating is that when you DO need to change your car, get a more eco one. What's the problem with that?

You and TJ are making up straw men, I'm afraid.

So you're telling me that a Prius is more environmentally friendly over its life than a Series III Landy running on chip fat?

Not necessarily. Waste chip fat is great, but there's very little of that around compared to petroleum. If you start growing crops for fuel you get into a world of trouble. Even Bush's fairly tame biofuel programme has tripled the cost of corn in Mexico and other places already. We need land for food - stopping growing food just so you can cruise around in a V8 landy when people are starving is deeply immoral, don't you think?

Biofuels do however have a lot of potential, and in 20-30 years we might really see that. Oceanic algae, biofuel crops on marginal land, cellulosic ethanol from waste or wood etc etc are all great possibilities.

So, clubber, steam turbine in a car. Wheres the water coming from ?

It gets recycled... Although you still need to lose some heat for this system to work.

A prius in city conditions is using 0 petrol. Beat that in your conventional car.

Not for long. The battery only powers the car for about 2 miles at best (although they are workign on one that'll do 40 miles). However, it loses a lot less MPG in town than other cars when you do town driving. I go from say 63mpg motorway to about 56 in town (best figures), whereas my Passat TDI goes from about 55mpg to 35mpg.

I'm pretty sure that it's also partly because diesel is a dirtier fuel in the US. I know a couple of years ago modern 'clean' diesels like we have in Europe weren't possible over there because of the fuel quality.

True - but it's also a dirty fuel here. It produces a lot of NOx (which is an irritant and causes smog) and diesel soot particles. These particles have been implicated in some very bad things.

The prius is a bit greenwashy. After maybe 15 years and 200k+ miles it might offset the extra production costs and environmental impacts, but how many are likely to see that?

Priuses are very reliable. The can easily rack up 200k miles and plenty more. The Prius is a brilliant bit of automotive engineering, and is full of cool stuff that you lot don't know about. For example, we all know that most engine wear happens in the first few seconds of driving, right? Well the Prius uses almost all battery power (unless you boot it) for the first minute or so of driving, until the oil's warmed a bit and circulated about the engine, to protect it. I don't think the car's old enough to start seeing the benefits from that yet, but I bet you'll see far fewer of them blowing smoke in 10 years time.

X6 may be daft but it gets rave reviews from the motoring press 😉

And with the most popular 35d diesel unit, it's emissions are probably lower than many of your cars.

You're better off directing your anger at ridiculous massive hybrid 4x4s like the Lexus rx400h or the even sillier GS450h.

Mol - you are still conveniently dodging the battery manufacturing issue... And you are better off fixing that RR than buying a whole new car.

Solo - I don't work in the auto industry btw, but sometimes I wish I did 🙂

The coolant steam turbine thing does still need a radiator of some kind to disperse some heat - the turbine needs a hot side and a cold side to work, otherwise the steam won't be able to expand into anything. Or you need two water pumps - one normal one and one to force water back into the block to create enough of a vacuum to allow steam expansion on the cold side of the turbine.

But I agree on the £25/gallon petrol. TJ should note that there is already a 95mpg car out (Seat Ibiza Ecomotion) with petrol at what, £5-6/gal. All you'd do with that kind of taxation would be strangle the economy severely. Unfortunately (and I wish this were not the case) for the short term future people still need to get around to make the economy work.

BristolBiker.

Thanks for that post, as more of the detail has been revealed, I can see why someone may decide to divert RD funds in that direction.

However, temps in different parts of the world might mean limited application. Still, worth a look I guess, hence BMW's decision.
😀

Mol - you are still conveniently dodging the battery manufacturing issue... And you are better off fixing that RR than buying a whole new car.

Indefintiely?

I don't know about battery manufacturing. I would hazard a guess that hybrid car batteries are a tiny proportion of the world's battery manufacturing capacity.

There are other factors tho. How much energy does it cost to manufacture a gearbox? They are big, and heavy (much heavier than a Prius battery) and the Prius doesn't have one.

I keep having these brilliant ideas, then someone comes out with it years later and everyone's like 'ooh, isn't that clever!' Grr...

I think the key here is that an idea that remains in your head will always just be an idea.... the 'clever' bit is patenting/licensing or commercialising/selling the product.... and alot of that is about having the balls to back yourself and your ideas. ....None taken.... 😉

There are other factors tho. How much energy does it cost to manufacture a gearbox? They are big, and heavy (much heavier than a Prius battery) and the Prius doesn't have one.

In that case, is a tonne of steel worse for the environment than a tonne of oil/acid/poison? I don't quite get your equation of more weight = more impact on the environment. Maybe we should also build much lighter houses then?

If I worked for flippin Toyota I could just tell someone and it'd get looked at. I'm not prepared to quit my job and sell everything to get invovled with this market... There's already a bloke who's invented a 6 stroke engine that scavenges most of the waste heat and converts it into work - he's even built a 1cyl engine that demonstrates it perfectly, but he's having massive trouble getting any big company interested.

When I get a house that'll fit a workshop in the garden, and enough money to start buying up old cars and engines for modding purposes, then I might be able to get something going 🙂

My latest idea is a 2 stroke engine with an external compressor. Instead of compressing 2l of air every two revs that you don't need, you only compress what you need to burn the fuel you need to get the car moving...

Mat - people complain about the weight of the Prius battery - I was just saying that the weight is not a factor.

Manufacturing things like gearboxes must be fairly energy intensive though?

TJ - you're being a bit silly to be recommending tiny cars as a replacement for big cars. Of course it's more economical to drive a tiny car. But today, people want crash protection, comfort and a car big enough to carry a family around in.

Bobbins - of course you can do this with a small light economical car - and anyway light does not mean small - your prius could be 2/3 the weight with all the useless gadgets removed. Light cars can have good crash protection

And as you know - the prius does have a gearbox - not a conventional one but it does have complex and heavy set of gearing to allow it to work - plus two electric motors as well. No weight saving there

The prius is a big heavy car. It does nothing that a yaris or a wagon R doesn't do. however you need the status symbol of a big luxury car.

All you'd do with that kind of taxation would be strangle the economy severely.

Which is why I suggest doing it over a 20 yr span.

Mol - I don't complain about the weight of the battery - in fact the Prius is a pretty light car overall. But it's what's in it and how it's made that does concern me. It's rather hard to find any info about it strangely enough...

your prius could be 2/3 the weight with all the useless gadgets removed.

Right, so you are saying there's 450kg of useless gadgets in my Prius? I'd be keen to see the breakdown of that weight.

Go on, back up your wild claims 🙂

And as you know - the prius does have a gearbox - not a conventional one but it does have complex and heavy set of gearing to allow it to work - plus two electric motors as well. No weight saving there

Stats please? The HSD and the motors are tiny and I don't see why they'd be heavy. But I'd be happy to be proved wrong if you can find some figures.

A Prius is not a big heavy car at 1300kg or so. Yes, heavier than a 2CV but I'd not put my family in a mobile biscuit tin if it's all the same to you.

It does nothing that a yaris or a wagon R doesn't do

It carries four adults and their stuff in comfort.

As for status symbol - you are raving mad there mate. It's the car I feel embarassed about mentioning since I know basically everyone will slag me off and call me a total retard for ever buying. So how can it be a status symbol?

All I wanted was a decent sized economical car. Why am I so bad for this?!

PS when I bought it the Aygo available at the time had the exact same CO2 emissions. So give over with the Aygo thing please.

It's rather hard to find any info about it strangely enough...

It is, yes. Any search is polluted by the raving crap about hummers being greener which all stemmed for one paid-for biased report that was full of stupid assumptions and sheer crap.

They are just plain old NiMH batteries though, so information about those should be available...?

Molgrips - the point you keep ignoring is the lifetime environmental penalty. A prius is bad for this - how bad we don't know because toyota will not release any info on the batteries. Even without the batteries it is not good because of the weight. More weight = more resources.

of course a simpler smaller lighter car can carry a family and their stuff in comfort and safety.

Look at the schematics for the engine and transmission - the gearing and electric motors and batteries are a lot bigger than a conventional gearbox.

if the pious was serious about reduced lifetime pollution rather than zero emissions in towns it would be a lot lighter.

As for stuff that could be removed. i'd have to go thru the car but. Electric windows, all that fancy dash, most of the speakers from the stereo, sat nav, Air conditioning- that sort of thing. Then as it gets lighter you then need less power to drive it - hence smaller lighter engine.
But all those toys are essential to you are they not .

another point you ignore is that in order to reduce emissions significantly you have to accept compromises in other areas.

Well the older model Prius came out in 2003. It's good for 60mpg in normal driving, and is larger than a Golf. It's also petrol, which is cleaner and often cheaper. At the time I got mine, in 2006, nothing of its size had anything like its CO2 emissions and could not match consumption either; only tiny little Aygos etc could come close.

It has its place, but it depends what you call normal driving. Highway driving I can achieve 60mpg from my diesel estate car, in 2000 with emissions of 140 IIRC.

These days both sides have advanced a lot, but if you drive a prius with any gusto you're dropping the MPG way below a similar car.

Dont forget the battery lifespan, the energy and chems going into making it etc. There are different ways of making a green car. Look at things like the old landy 90s, while they're not the most efficient of cars many of them have lasted 30 years with only small repairs and changes, while in that space of time most people will have had 6 cars. I think part of the problem is we treat cars as disposable items, I know loads of cars that have been scrapped by the age of 10 - that's criminal, criminal that such a vast amount of enery went into making them and they're now not solid enough to survive a decade.

Toyota have done a lot of research into "whole life" carbon use - i.e. power used to make, run and repair the vehicles. From this they concluded that the hybrid system was best (easy to realise and pretty good at what it does), all electric cars make no sense for the majority of car users, petrol cars can be made just as good as hybrids currently but they need to press that technology on. All sensible points. Wouldn't make me buy a huybrid at the moment, but I'm glad it's being worked towards. Personally I've never been a new-car person, I'm happy with a 10 or even 20 year old car that others would have dumped by now, my 10 year old D estate can reach 65mpg on a run. My 20 year old sports car can do 0-60 as fast as I want it to, im not sure I see the reason for buying new all the time as some people do, but it keeps me in a supply of older cars 🙂 .

Molgrips - the point you keep ignoring is the lifetime environmental penalty. A prius is bad for this - how bad we don't know because toyota will not release any info on the batteries. ven without tha batteries it is not good because of the weight. More weight = more resources.

To be fair I went to a lecture given by Toyota on their hybrid technology, and the one thing they did was work through the numbers and show that, from an energy standpoint and based on their expected lifespan at least, the hybrid still stacks up similarly against similar non-hybrid models.

another point you ignore is that in order to reduce emissions significantly you have to accept compromises in other areas.

Correct, but the general population would never go down that route as a step change, so it would be pointless to introduce it, far better to accept a slower introduction of the technology and work towards that when it is accepted. Bear in mind no company wants to commit suicide by introducing a super-green car that no-one gives a damn about.

I agree with TJ on the weight issue.

Cars have been getting heavier for years MkI Golf was 900kg MKVI golf is about 1500kg. Manufacturers are beginning to reverse the trend but there is a long way to go.

Removing wieght become a virtuous circle. Lightweight car needs a lighter engine to make it run acceptable, less engine power so lighter transmission and so on.

The average cyclist has about 1/3hp at their disposal yet they can power their vehicle comfortably at 20mph becuuse combined wieght of rider/bike is <100kg.

Many of your standard safety features (like safety zones for occupants, ABS, airbags, SIPS etc) are heavy. By definition. Of course the best option would be to say everyone has to drive carefully and therefore not need any safety kit and not need a powerful engine. But reality sucks.

porter_jamie - Member
Are you saying that a petrol engine is most efficient at full throttle ?

absolutely!

I thought we were talking about fuel efficiency, not maximum power.

We need land for food - stopping growing food just so you can cruise around in a V8 landy when people are starving is deeply immoral, don't you think?

Breeding more people when people are starving is even more immoral.
Should I stop driving my Land Rover just so other people can keep on having babies ?

coffeeking - so the best toyota can say is [i]by thier own figures[/i]that they wont release to anyone else that its

the hybrid still stacks up similarly against similar non-hybrid models.

Not very good is it. And I don't believe their figures anyway as they won't let independents look at them.

[i]I'd love a hybrid Yaris, if they made one. Unfortunately I can't afford three or four cars, one for every possible eventuality. If I could though, I would![/i]

And this is the real 'issue' for the average car owner, at different times you need different cars; especially if you've a family.

If I was buying cars with my wallet/brain, it would have to be a pair of s/h mid-sized MPV (example, Zafira) diesel - we've 3 teenage kids plus non-driving grandfolk.

Midland - a petrol engine is most efficient at full throttle - in that it turns more of the energy in the fuel into energy at the wheels at full throttle. at part throttle the frictional losses are almost the same as at full throttle and the combustion is less efficient - so for half the fuel you produce less than half the amount of power at the wheels.

this is why the experimental fuel challenge cars have tiny highly tuned engines run flat out and then they coast.