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Offline eric l

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« on: 12/02/2007 19:18:46 »
I have posted the question as a sideline in the topic about diesel fuel and petrol (gasoline), but to no effect.

In the late sixties and/or early seventies the rotary engine (Wankel-engine) was heralded as the engine of the future.  NSU had one model, Mazda had two or three models equipped with them.  There were also two motorbike models :  one by Suzuki (chain driven and axis of the engine transversal) and an other by Hercules (shaft driven, axis of the engine lenghtwise).
NSU became part of the Volkswagen-Audi-Group, and the Ro80 disappeared.  As far as I know, Mazda does not market Wankel-engine driven cars any more. And the motorbikes I mentioned are becoming collector's items.

A simmilar story for the gasturbine.  I remember - it must have been around 1970 - a gasturbine driven racing car at Le Mans, making the full 24 hours.  But it did not appear again.  The only occasions where you can see a moving gasturbine other than in a plane are tractor pulling events.  I suppose the noise is a problem here, an maybe it is difficult to make a gasturbine small enough to fit in a car.

Anyone around who has information about either of this (or both) ?

 


 

Offline iko

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« Reply #1 on: 12/02/2007 19:26:13 »
Electric engines seem to be a promise
in developing high-performance and no
environmental pollution...

 

paul.fr

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« Reply #2 on: 12/02/2007 19:33:44 »
Electric engines seem to be a promise
in developing high-performance and no
environmental pollution...


But, the most popular model right now i believe is the Prius, spell check anyone, and that is still far from ideal.
one of the big American motor manufactors have recently unveiled a prototype electric car but have you seen the battery pack! and it may be another 10 years utill it rolls off the assembly line.

Paul
 

Offline neilep

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« Reply #3 on: 12/02/2007 20:57:54 »
This is my current favourite car. My cousin has one and me wants it !

its the Mazda RX8 and it uses a Rotary engine and does silly perfomance from only 1300cc !!

It utilizes two 650 cc units !!..what ever that means !!










 

another_someone

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« Reply #4 on: 13/02/2007 01:56:30 »
Problem with wankel engines is that they are a lovely idea but very difficult to deal with oil seeping past the seals.

Electric cars have many advantages, but low pollution is a rather complicated issue with them - what it does is shift the pollution from where you can see it (in the car exhaust) to where you can't see it (at the electricity generating station).  OK, you have more choices about how you generate electricity in a large stationary electricity generating plant than you have in the confines of a portable motor car engine, but you still have to be careful that you look at the whole picture, not just a small part of it.

One problem is, when you say it is 10 years off before an all electric car hits the streets, that car manufacture is such a large scale business that doing anything can take 10 years, just to build the production plant for it, let alone the technology.

Nonetheless, there are a few specialist electric vehicles out there, and they at least will explore the technical issues.
 

another_someone

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« Reply #5 on: 13/02/2007 02:33:30 »
If you want to try an electric vehicle today:

http://www.electriccarhire.com/?gclid=CPaMxZKlqooCFSdXMAodz1Zjrw

Ofcourse, there is still the problem about how you recharge the car on a long journey.
 

Offline daveshorts

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« Reply #6 on: 13/02/2007 09:37:27 »
It is definitely possible to build a gas turbine small enough to fit in a car, the military have man portable gas turbine water pumps for fire fighting. I think the problem is more maintainance, and fuel efficiency, as I think small turbines are probably not very fuel efficient.
 

another_someone

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« Reply #7 on: 13/02/2007 13:57:06 »
It is definitely possible to build a gas turbine small enough to fit in a car, the military have man portable gas turbine water pumps for fire fighting. I think the problem is more maintenance, and fuel efficiency, as I think small turbines are probably not very fuel efficient.

Not sure the matter is as black and white as that, as in essence a turbo charged car is a hybrid piston/gas turbine vehicle - it is just about how you balance the function of the turbine and the function of the pistons, and where you take the energy from.

One problem I can see from a pure gas turbine is that of torque, particularly since you cannot run them at low revs - and that is why hybridising with a piston engine can provide the low rev torque.  Another possibility I would imagine is using a turbo-electric hybrid, as has been used in railway engines before (although their power requirements are ofcourse different from that of a personal motor vehicle).
 

Offline lightarrow

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« Reply #8 on: 13/02/2007 14:33:30 »
Wankel engine:
 

Offline eric l

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« Reply #9 on: 13/02/2007 14:46:10 »
Thank you for all the info - some of it quite new for me.
For what it's worth, I'll add here what I've been told about gasturbines.  (I have most of it from a guided tour at a plant where they had recently installed CHP or Combined Heat and Power, with a gasturbine).  
It seems that medium and big sized gasturbines are more fuel efficient than other (internal combustion) engines.  Problem with small engines, as would fit in a car, is that they are simply much more expensive than piston engines.  (I remarked that they would probably be cheaper if manufactured in the same quantity as piston engines, but got no answer on that).  
Also, in the case of CHP, the heat produced at the exhaust is effectively used.  This would probably not be the case if the engine were placed in a car or motorbike, so fuel efficiency would be far less.  (I had no argument against this)
And, indeed, a gasturbine is almost useless at low revs.  
 

Offline ukmicky

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« Reply #10 on: 14/02/2007 00:09:48 »
Hi George its really nice to see your back. That must have been one hell of a new years hang over you had, next time send me an invite :)

Talking about gas turbines and things ,did you know there was a motor cycle manufacturer i believe in America who actually built and sold a large number of motor cycles powered by an actual jet engine which was as usable as any other bike. The only reason it didn't catch on was due to the riders burning themselves on various parts of the bikes.
« Last Edit: 14/02/2007 00:12:11 by ukmicky »
 

another_someone

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« Reply #11 on: 14/02/2007 01:47:54 »
Hi George its really nice to see your back. That must have been one hell of a new years hang over you had, next time send me an invite :)

 :)

I wanted to spend time doing other things - and if I end up spending as much time on here as I did before, I shall probably take another sabbatical.

Quote
Talking about gas turbines and things ,did you know there was a motor cycle manufacturer i believe in America who actually built and sold a large number of motor cycles powered by an actual jet engine which was as usable as any other bike. The only reason it didn't catch on was due to the riders burning themselves on various parts of the bikes.

There seem to be several private project that use gas turbines (some of them also refer to them as jet powered, although I would draw a distinction between a true jet, that relies on thrust, and a gas turbine that relies on shaft drive).

Aside from heat, they also have problems with fuel consumption, and immense turbo lag.

http://www.badbros.net/jetbike.html

http://www.popularmechanics.com/automotive/jay_leno_garage/1302876.html
 

Offline albert

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« Reply #12 on: 14/02/2007 22:13:39 »
Battery powered vehicles are the only way forward.

Serious advances in battery and capacitor technology really should have the 'Hydrogen Economy' exponents shutting up shop by now. The trouble is with who owns the chain of energy supply - the likes of BP, Shell, Exxon - want to keep hold of their monopoly and so Mr.Bush and Mr.Blair back them by wasting public money for research and development.

Hydrogen is such an inefficient and inconvenient way of moving about. It uses so much energy to creaate it, it's dangerous, and as I understand it causes catastrophic damage to the atmosphere - more so than C02.

So I'll be hoping that the likes of Toshiba come up with the goods soon and we can all lead healthier lives with zero emission (for the user) vehicles whizzing about the streets powered by carbon neutral nuclear/renewable power generation.

Albert
 

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« Reply #13 on: 14/02/2007 22:29:11 »
Battery powered vehicles are the only way forward.

Serious advances in battery and capacitor technology really should have the 'Hydrogen Economy' exponents shutting up shop by now. The trouble is with who owns the chain of energy supply - the likes of BP, Shell, Exxon - want to keep hold of their monopoly and so Mr.Bush and Mr.Blair back them by wasting public money for research and development.

The problem is not so much whether one fuel is better than another, the problem is trying to set up the infrastructure to support it.  In that respect, it matters not whether you are talking about hydrogen or battery, you need the support infrastructure to allow you to top up during your journey (i.e. filling stations).  The car is the easy bit.

Ofcourse, one other option still remains, and this would have the minimum disruption to the supply chain, is the use of synthetic hydrocarbons rather than using mineral hydrocarbons.

Quote
Hydrogen is such an inefficient and inconvenient way of moving about. It uses so much energy to creaate it, it's dangerous, and as I understand it causes catastrophic damage to the atmosphere - more so than C02.

I'd agree with most of that, but the dangers of hydrogen have been overplayed (it is less dangerous than natural gas, which most of us have piped into our homes).
 

Offline iko

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« Reply #14 on: 14/02/2007 22:42:19 »
Now that all China is going to be 'motorized',
In our old Europe it's our turn to go back to the...
PERFECT MACHINE!

 

Offline scanner

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« Reply #15 on: 14/02/2007 23:07:59 »
To follow on from my other post elsewhere.
Diesel is the answer, petro-diesel and bio-diesel can be mixed or substituted in any proportion and the two can both be distributed through the same network with much if any modification. Once production is scaled up bio-diesel can be cheaper to produce than petro-diesel and given something like the massive, stupid, misguided subsidy given to LPG in the UK could rapidly take over. Even better bio-diesel can be made from all the waste oil and fat available from food production and sale establishments every where. Just wait until you can fill the car and the occupants at a McDonalds or Burger King drive through?

Petrol/electric Hybrids like the Prius do not deliver anything like their claimed mileage in real life use and battery cars are a joke. If you work out their MPG from the quantity of fuel needed to be used to generate the electricity needed to charge the battery and then look at the pitiful range they have they are simply short distance city cars at best.

Diesel on almost any suitable fuel has greater range than petrol, greater safety than petrol, gas (LPG or CNG) or Hydrogen and despite what some of your less well informed (or should that be more ill informed)correspondents think lower OVERALL harmful emissions - simply because they emit less of everything per mile. Catalysts clean up petrol emissions (once they are properly warmed up - and in the UK 75% of all journeys do not allow the catalyst to fully warm up) but at the cost of 10-20% higher fuel consumption - a good idea? I don't think so.
 

Offline albert

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« Reply #16 on: 15/02/2007 01:00:14 »

The problem is not so much whether one fuel is better than another, the problem is trying to set up the infrastructure to support it.  In that respect, it matters not whether you are talking about hydrogen or battery, you need the support infrastructure to allow you to top up during your journey (i.e. filling stations).  The car is the easy bit.


Yes that's true. Current recharge times are look to be minutes for the latest UltraCapacators.

So should we just dump the car? I don't think that'll happen any time soon. There's an interesting comment I heard about the car being that last bastion of perceived personal freedom left - hence all the kerfuffle over speed cameras and RFID road pricing. If that's true then it's a pretty sad reflection of how stupid we're all getting and how empty our lives have become.

But the fact remains that our whole society has developed over the last 50 years on the basis of full and unrestricted mobility of the population - shops at the edge of town, jobs 40 miles away, leisure and recreation facilites no longer on the doorstep.

It wasn't always this way - once there were no dual-carriageways and no motorways, people worked where they lived and walked to the shops - but there's no going back and so it is STOOPID to try and turn back the clock unless we're going to also try and restructure the way towns and cities are built. Public transport cannot solve this, so we are stuck with the car and that in the future we will be dependent on low-power, low weight, power efficient EV's to move us around.

In the short-term we should introduce strict emission AND power limits on cars if we're that bothered - this will change the design and performance profiles of the machines and will prepare us for more moderate expectations for our future personal transportation podules. It'll be goodbye to Ferrari, Range Rover and Lambo - but really - who needs 300bhp to sit in a traffic queue or trundle at 40mph in road works?

Quite how near that future is is a matter for science and the correct routing of R&D development money through universities towards viable technologies and NOT headline grabbers like that ludicrous 'Intelligent Energy' hydrgen powered version of the Raleigh Grifter that gets so much exposure and has cost goodness knows how much. They should rename it 'Intelligent Elephant' and paint it white!

Rant complete...

Phew!

Albert
 

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« Reply #17 on: 15/02/2007 01:03:34 »
Even better bio-diesel can be made from all the waste oil and fat available from food production and sale establishments every where. Just wait until you can fill the car and the occupants at a McDonalds or Burger King drive through?

Nice idea, but it will only happen over the Chancellors dead body - the loss of tax revenue would be unacceptable.  The government will never agree to anything other separate distribution channels for motor fuel so that it can be taxed separately.

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Petrol/electric Hybrids like the Prius do not deliver anything like their claimed mileage in real life

They are still very early technology (you made the point about how much the diesel has improved in the last quarter century, but the hybrids have only been here for less than a decade).

I actually see diesel to be a logical partner to hybrids, since the lack of flexibility of a diesel engine scarcely matters when you use an electrical transmission system.

Quote
use and battery cars are a joke. If you work out their MPG from the quantity of fuel needed to be used to generate the electricity needed to charge the battery and then look at the pitiful range they have they are simply short distance city cars at best.

The major advantage of battery cars is low weight - otherwise, little else.

Range is something that is constantly improving, but at present they are a niche market (although if they can be produced cheaply enough, they could make a very useful second vehicle for local trips).

 

Offline scanner

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« Reply #18 on: 15/02/2007 13:58:45 »
Even better bio-diesel can be made from all the waste oil and fat available from food production and sale establishments every where. Just wait until you can fill the car and the occupants at a McDonalds or Burger King drive through?

Nice idea, but it will only happen over the Chancellors dead body - the loss of tax revenue would be unacceptable.  The government will never agree to anything other separate distribution channels for motor fuel so that it can be taxed separately.

Quote
Petrol/electric Hybrids like the Prius do not deliver anything like their claimed mileage in real life

They are still very early technology (you made the point about how much the diesel has improved in the last quarter century, but the hybrids have only been here for less than a decade).

I actually see diesel to be a logical partner to hybrids, since the lack of flexibility of a diesel engine scarcely matters when you use an electrical transmission system.

Quote
use and battery cars are a joke. If you work out their MPG from the quantity of fuel needed to be used to generate the electricity needed to charge the battery and then look at the pitiful range they have they are simply short distance city cars at best.

The major advantage of battery cars is low weight - otherwise, little else.

Range is something that is constantly improving, but at present they are a niche market (although if they can be produced cheaply enough, they could make a very useful second vehicle for local trips).

No reason why McD and BK couldn't have pumps as well many are in any case located on or close to filling stations.
It is possible to register as a bio-diesel producer/user and submit your own returns to HMR&C to pay the duty post use. I know several people who have done it.

Peugeot Citroen and I think Smart are already developing  diesel hybrids and you are wrong in stating that the technology is less than a decade old. Railway locomotives have been using TRUE hybrid technology, both diesel electric AND diesel hydraulic for decades.
Diesels do not suffer from "lack of flexibility" my daughter's Punto JTD will do from below 30 to over 100mph quite smoothly in 5th gear. Could tell me one petrol car that is more flexible than that? Indeed could you tell me exactly how much more flexibility you would like.
People who have never driven a diesel car or if they have, never realised that you do not drive them in anything like the same way as a petrol car as their power delivery is very different, often think that because the power band is narrower over all than a petrol this is a problem. However, the USEFUL power band is just as wide AND because the torque is much higher, the diesel can pull much higher gear ratios and thus the speed range in each gear is virtually the same, if not wider, with a diesel.
It is the speed range that matters in each gear, NOT how manic the engine is sounding.

In a diesel it is rarely necessary to change down to get enough torque for safe overtaking as max torque is produced well down the rev range (it is torque that wafts you safely past the other car not bhp) Petrol cars often need a down change or two to bring the engine "back on the boil" after cruising for a while and this makes for very tiring driving - continually stirring the gearbox trying to find the right gear to suit the high revving petrol.

If you think diesels are so "inflexible" I suggest you try a good modern one sometime. The turbo has transformed the diesel in a true WIN-WIN way TD's produce more torque, pull higher gearing and use less fuel than their normally aspirated equivalents - what more could you want?
« Last Edit: 15/02/2007 14:12:19 by scanner »
 

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« Reply #19 on: 15/02/2007 14:35:56 »
No reason why McD and BK couldn't have pumps as well many are in any case located on or close to filling stations.
It is possible to register as a bio-diesel producer/user and submit your own returns to HMR&C to pay the duty post use. I know several people who have done it.

Possible - even then, I would ask if the oil available from these sources would ever satisfy more than the smallest fraction of potential demand.

Quote
Peugeot Citroen and I think Smart are already developing  diesel hybrids and you are wrong in stating that the technology is less than a decade old. Railway locomotives have been using TRUE hybrid technology, both diesel electric AND diesel hydraulic for decades.

Not really comparing like with like.  You mentioned that diesels were only actively developed since the 1980s, yet I could argue that diesels have been around since Otto Diesel invented the process in the 1890s.

What I meant was that the current application to small scale use in motor cars is extremely new - ofcourse, larger vehicles, as well as stationary diesel electric generators have been around most of the 20th century.

When you are talking about the efficiency of the use of the technology in motor cars, you have to look at how long they have had to solve the problems specific to motor cars, not how long the generic technology has been around.

Quote
Diesels do not suffer from "lack of flexibility" my daughter's Punto JTD will do from below 30 to over 100mph quite smoothly in 5th gear.

Maybe a slight difference in what we are talking about.  Maybe I should have used the term 'responsiveness' rather than 'flexibility'.

Yes, diesels do have a very wide band over which they can pull useful torque - what I meant was the time it takes to spin up revs (e.g. when you want to pull away rapidly, not so much about how few gear changes on needs).  Indeed, it may be argued that the reduction in the need for gear changes can make diesels more relaxing to drive than some petrols, but less suitable for boy racers.

I have driven a Fiat Tipo diesel (not mine) of some years of age.  It would do pretty much anything I needed of it, but certainly did not have the responsiveness of a petrol engine (but then, my boy racer days are long gone).
 

Offline scanner

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« Reply #20 on: 15/02/2007 17:19:02 »
You have to look at the total volume of oil available for recycling my comment on McD and BK was the sort of light-hearted throwaway line that I'm told is the norm on here.

The Armed Forces are commissioning portable waste veg oil recycling plants so that they can use field kitchen waste as fuel.

The forces sensibly went 100% diesel - even Despatch Rider's M/bikes! - recently so that everything they use from Aircraft and tanks to motorcycles and  generators can all use the same fuel.
Diesel/AVTUR is also MUCH safer to store in bulk under combat conditions than any other fuel.

You may have a point about automotive hybrids but the Prius/Insight appear to have done little to advance the cause by failing miserably to live up to the hype and delivering pathetic fuel economy in real world use compared to equivalent diesels. Furthermore the little matter of the environmental problems created in making and disposing of the battery packs has yet to be addressed.

If the last diesel you drove was a Tipo then I will accept your experience is way out of date. I used to own it's Big Brother a Tempra Estate and now own it's descendant a Marea Estate and there is no comparison. The later Mareas/Punto with the common rail JTD engine are yet another vast improvement. I doubt if you would notice any difference whatsoever between comparable petrol and diesel models of the same car these days.

A good example is http://www.alfa147collezione.co.uk/ [nofollow]both version have 120 bhp but the diesel is a second faster from 0-62mph and has a top speed of 120mph (as opposed to 121mph for the petrol version) and approx 30% better fuel economy.

The Alfa is in effect the modern Tipo, same size and uses the modern version of the same diesel engine and trounces it's petrol sibling on all counts bar 1 highly illegal mph.
Shame that the diesel costs about 1000 more, but it does retain that price premium throughout it's life, whist recovering it through fuel savings and reduced company car tax for business users, in a couple of years.

I have the solution to the electric car range and refuelling problem (once the battery making, carrying and disposal problems have been solved) run them on diesel. In fact almost any form of diesel. Fit them with a small generator pack - it only has to supply enough current to meet mean consumption as the peaks can be recharged when the car is running below peak (a lot of the time in traffic). That pack could be powered by a small Gas Turbine such as those used in large model planes, target drones etc. The GT could then happily hum away at it's optimum speed and the waste heat can be utilised to solve the other problem of electric cars - no heater.

« Last Edit: 15/02/2007 18:52:06 by scanner »
 

Offline albert

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« Reply #21 on: 18/02/2007 23:00:20 »
To suppliment the mcD and BK fuel supply I made a proposal on another site that liposuction clinics should donate their erm... byproducts (which are likely to be have been sourced from mcD and BK) so that the couch potatoes of the future can do their bit for humanity...

Then some boffin replied - raining on my parade...

"Let us not assume free energy, but rather let us assume the entire planet is filled with obese couch potatoes. If 100 pounds of fat could be harvested from each of 6 billion people each year, that is 600 billion pounds or 300 million short tons of fat each year. If we assume human fat has the same energy content as crude oil, and since 1
ton of oil equals about 8 barrels, this is 2.4 billion barrels of oil equivalent (BOE). Since the world currently consumes about 30 billion barrels of crude oil per year, this method will not go far toward eliminating our dependence upon oil."

Ah well - out of the madness a good idea might just turn up!

Albert
 

paul.fr

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« Reply #22 on: 18/02/2007 23:04:09 »
To suppliment the mcD and BK fuel supply I made a proposal on another site that liposuction clinics should donate their erm... byproducts (which are likely to be have been sourced from mcD and BK) so that the couch potatoes of the future can do their bit for humanity...

The same such idea was in a storyline on Boston Legal last week! are you a script writer on the side?

Paul
 

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« Reply #23 on: 18/02/2007 23:59:49 »
I think there really are two questions that we have to consider, to some extent separately, here.

Firstly, what is the ideal motor for a motor car, and although there is still some way to go for that technology to be fully mature, I think it is valid to say that it is the electric motor.

The separate question is what is the best energy storage system for a motor car.  Is it better to generate electricity away from the vehicle itself, and store the electricity as capacitive or chemical electrical charge onboard the vehicle; or is it better to store a liquid fuel (e.g. petrol or diesel) on board the vehicle, and convert it to electricity in situ.

At present, the latter option seems to be the more energy efficient, although politically, generating pollution in some far remote location, and then shipping the relatively pollution free electricity to the congested cities is more tolerable, even if it is less energy efficient.

Ofcourse, that is true as long as we have relatively cheap and available supplies of oil to use as a liquid fuel.  Once we start having to synthesise liquid fuels because we have run out of mineral sources, then the equation might change (but, despite the doom and gloom merchants, it seems unlikely that we will run out within the 50 to 100 years).

In any event, given the 50 to 100 year leeway we still have, it does give us ways to think of other ways of transporting energy (it is the convenient transportation of energy that is the major problem for vehicle transportation, rather than the availability of energy as such - although the latter is a wider issue but not one particular to motor vehicles).
 

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« Reply #23 on: 18/02/2007 23:59:49 »

 

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