229 replies to this topic

[Moon Tricky]

Of all the latest hybrid technologies, Idle Stop seems to be, in principle, the most sensible. Why burn fuel while you're standing still? It's obvious how marketing teams can sell this sort of idea. But it's not as easy as that. Stopping and starting an engine all the time leads to excessive wear and tear. Either you over-engineer it, or it doesn't last very long. That's not very good. Which is a shame. But what I'm wondering is, what exactly is causing all this extra wear and tear? And can anything be done about it?

Furthermore, how much power does it actually take to idle an engine (say a 2 litre inline 4), and what is the efficiency of an idling engine? My thought is, if an idling engine turns out to be less efficient than the (engine at peak torque)-generator-battery-motor route, would it be possible to make savings by keeping the engine turning over using the motor? Would that even help?

[McGuire]

Originally posted by Moon Tricky

what is the efficiency of an idling engine?

is this a trick question?

[Moon Tricky]

Originally posted by McGuire


is this a trick question?

Err... maybe...

Obviously it's 0% in terms of the actual excess power you get out of it to do useful stuff. I mean, in terms of the fuel you put in versus how much power it takes to actually turn the thing over.

[Zoe]

Idle stop already was a big hoopla in the eighties around here. For some reason it didn't remain popular despite some car models being offered with such a device by the factory.

And of course, there's the comfort issue - A/C doesn'r really work that well when the engine's not running...

Zoe

[Todd]

Originally posted by Zoe
Idle stop already was a big hoopla in the eighties around here. For some reason it didn't remain popular despite some car models being offered with such a device by the factory.

And of course, there's the comfort issue - A/C doesn'r really work that well when the engine's not running...

Zoe

Honda has solved the A/C issue by fitting an electrically driven compressor to maintain cooling when the engine is stopped. There is still the issue of wear and tear on the engine though. Since the propulsion motor serves as the starter in some hybrids, I don't think wear on the starter is such an issue.

[kikiturbo2]

Of all the latest hybrid technologies, Idle Stop seems to be, in principle, the most sensible. Why burn fuel while you're standing still? It's obvious how marketing teams can sell this sort of idea. But it's not as easy as that. Stopping and starting an engine all the time leads to excessive wear and tear. Either you over-engineer it, or it doesn't last very long. That's not very good. Which is a shame. But what I'm wondering is, what exactly is causing all this extra wear and tear? And can anything be done about it?

IIRC, you are using somewhere around 1.5-2 litres of fuel per hour of idle..

as for idle stop... wear and tear, for me, would be on the crank and other rotating parts as you'd have questionable oil pressure and oil supply if you stopped the engine every so often..?

cheers

vlado

[Greg Locock]

If you think that is a big deal then either spin the engine up to a reasonable speed and full oil pressure before fuelling it, or fit an electric oil pump.

Personally I think option 1 would be a great idea for any engine, albeit the starter motor and battery might need a bit of an upgrade.

The big problem if you haven't got a seriously powerful electric motor is that when you hit the throttle at the start of the traffic light grandprix the (hey are we back on topic?) customer expects the car to move forwards, not run through some sort of start-up sequence.

[cheapracer]

VW had a try at a system in the late 70's that had a huge flywheel inbetween the engine and the transmission. It could be disconnected from both depending on the situation and at lights it free spun with the engine off (duh) and its inertia was good for about 3 minutes from memory. Of course you merely let the clutch out which reignited the engine before taking up the drive. The bulk of the mass was disconnected under normal driving, cant remember how.

I think idling gives the worst emmisions doesnt it rather than fuel saving considerations?

[kikiturbo2]

as for the oiling problems, I would prefer some sort of oil pressure acumulator, or an electric pump..
as for the starter, normal starter would not live too long with start - stop driving, if it was asked to crank the engine up every time... a combined starter/alternator in the flywheel is a much better idea.... and soon we get to toyota prius type of thing...

personally, I would ditch all this hybrid/stopGo/etc... technology and just concentrate on making useable sub 1000 kg cars... that is a much cheaper and simpler way of dealing with fuel consumption... never mind the fact that those cars would be a much better drive...

[Moon Tricky]

Originally posted by Greg Locock
If you think that is a big deal then either spin the engine up to a reasonable speed and full oil pressure before fuelling it, or fit an electric oil pump.

What is a "reasonable speed"? And surely it would be a good idea to lubricate it properly while it was getting it up to that speed?

If you did keep an electric oil pump running while stationary, would the engine still not need to be turned over, albeit slowly (maybe only 100rpm or so) in order for the oil to actually reach all the surfaces?

I'm taking a combined starter-generator as a given. I think they're a good idea in any case.

[zac510]

Sounds like a job for an oil accumulator during the short stop/start duty cycle?

[Moon Tricky]

Originally posted by zac510
Sounds like a job for an oil accumulator during the short stop/start duty cycle?

Good idea! I hadn't heard of them before so I just looked it up. It sounds like an ideal thing to use in conjunction with a combined starter-generator that can spin the engine up to above idling speed before any fuel is injected (preferably with all valves open to minimise pumping losses).

But is that enough? I'd be surprised if they weren't already doing that.

As for the "strategy", or the conditions for the engine stopping and starting again:
Stops when the car is stationery, the accelerator is not depressed, the gearbox is in neutral, and the engine has idled for a certain short amount of time (maybe 10 seconds or so).
Starts again as soon as the accelerator is pressed, and doesn't stop again until you've gone somewhere.

[cheapracer]

Dont know what the fuss is, most major traffic lights here (China) have time countdown clocks so you know when the lights will go green/red (usually 30 second cycle) - everybody switches off and restart at about 3 secs to go, simple!

[Moon Tricky]

Originally posted by cheapracer
Dont know what the fuss is, most major traffic lights here (China) have time countdown clocks so you know when the lights will go green/red (usually 30 second cycle) - everybody switches off and restart at about 3 secs to go, simple!

That's an interesting idea... not very good for your engine though.

[Todd]

Originally posted by cheapracer
Dont know what the fuss is, most major traffic lights here (China) have time countdown clocks so you know when the lights will go green/red (usually 30 second cycle) - everybody switches off and restart at about 3 secs to go, simple!

We've had world class traffic congestion for decades, and that is the first I've heard of this idea. As noted by Moon Tricky, the manual stop-start approach probably causes excess mechanical wear on the engine and motor. It would still be nice to sit at lights knowing that they will change and when. It would also cut out the Charlottesville Virginia Pig practice of disabling turn lane lights late at night so that they remain red, waiting in a hiding place, and then arresting anyone who gives up after 5 minutes and drives through the light.

[imaginesix]

Originally posted by Greg Locock
If you think that is a big deal then either spin the engine up to a reasonable speed and full oil pressure before fuelling it, or fit an electric oil pump.

Personally I think option 1 would be a great idea for any engine, albeit the starter motor and battery might need a bit of an upgrade.

The big problem if you haven't got a seriously powerful electric motor is that when you hit the throttle at the start of the traffic light grandprix the (hey are we back on topic?) customer expects the car to move forwards, not run through some sort of start-up sequence.

That would be one more benefit of using a powerful electric motor to drive away from standstill. I'd love to see a hybrid with a much larger electric motor and much smaller IC engine, a la Volt (maybe).

[phantom II]

Honda and Chev wouldn't have such systems if they were bad for the engine since GM offers 100 thousand miles on their trucks. All GM cars since 89 wont start if there is no oil pressure. With modern lubricants, turning the engine over from a stop especially when it is hot is no problem. Post office delivery trucks have been doing this for two decades now. The biggest obstacle for stopped engines is battery technology especially for 42 volt systems. Neither company runs the air conditioner compressor at the stop though. Bummer.

[phantom II]

This Sunday, Autolinedetroit.org will interview Bob Lutz about the Volt. 7am eastern. Streaming availible also Ipod and XML http://www.autolined...ne/archives.php

HIGH VOLTAGE

Synopsis: Ever since GM "electrified" the auto world with its Chevy Volt announcement a few months back, they've been working behind the scenes trying to make this "game-changing" concept into a viable production vehicle. Negotiations with Tier Ones & Twos, tweaking designs along with testing, testing and more testing recently led GM Vice Chairman of Global Product Development Bob Lutz to charge up to Traverse City, Michigan and update the automotive industry on the Volt's progress. As one of the main speakers at the Center for Automotive Research's Management Briefing Seminars, he not only spoke to the packed house but also stopped by Autoline Detroit's mobile studio for a talk with John McElroy. He brought along the Global Vehicle Line Executive for E-Flex, Frank Weber, so John could get the latest update first-hand on the design challenges GM faces as it hopes to bring this vehicle to market by 2010. In addition, John speaks to CAR Chairman Dr. David Cole to get his analysis on where the industry is today and what impact this seminar has on it year in, year out.

Originally posted by imaginesix
That would be one more benefit of using a powerful electric motor to drive away from standstill. I'd love to see a hybrid with a much larger electric motor and much smaller IC engine, a la Volt (maybe).

[Todd]

Originally posted by phantom II
Honda and Chev wouldn't have such systems if they were bad for the engine since GM offers 100 thousand miles on their trucks. All GM cars since 89 wont start if there is no oil pressure. With modern lubricants, turning the engine over from a stop especially when it is hot is no problem. Post office delivery trucks have been doing this for two decades now. The biggest obstacle for stopped engines is battery technology especially for 42 volt systems. Neither company runs the air conditioner compressor at the stop though. Bummer.

Honda has a second air conditioning compressor run by an electric motor in the Accord Hybrid, so that A/C keeps functioning when the engine is stopped. The 2nd generation Civic Hybrid has this feature too.

[phantom II]

The Chevy has a 200amp 12v alternator that goes to full blast restoring the juice in the batteries. Right now, it is 92'f in South Florida with 80% hunidity. I can assure you that the engine doesnt turn off, because that huge compressor takes a lot of HP to keep the big cab cool. The Honda woudnt be any different. The engines wont switch off in any big city in America during rush hour in the summer. Now let there be rain with your wipers and lights switched on and the situation gets worse. In mild conditions, it works quite well.

Originally posted by Todd


Honda has a second air conditioning compressor run by an electric motor in the Accord Hybrid, so that A/C keeps functioning when the engine is stopped. The 2nd generation Civic Hybrid has this feature too.

[kikiturbo2]

Originally posted by imaginesix
That would be one more benefit of using a powerful electric motor to drive away from standstill. I'd love to see a hybrid with a much larger electric motor and much smaller IC engine, a la Volt (maybe).

the only way hybrids make sense is if they had much smaller engines... IMHO, sub 1 tonne, with probably 30 HP diesel + 30 HP electric..

[Moon Tricky]

Originally posted by kikiturbo2

the only way hybrids make sense is if they had much smaller engines... IMHO, sub 1 tonne, with probably 30 HP diesel + 30 HP electric..

I don't believe so at all... the only hybrid technologies I consider particularly worthwhile are regenerative braking and, if it could be done effectively, idle-stop. Unless batteries start getting a lot more efficient very quickly, I don't think converting engine power into electricity is going to do very much. Think about it, any power coming out of the motor via the battery and the generator is going to have a well-to-wheel efficiency of less than the engine on its own. Just with the generator and motor, assuming they are 90% efficient, you're down to 81% of the engine's efficiency already. The efficiency of charging a battery depends on how full it is. It's only efficient when it's nearly full. Charging it from empty is typically only something like 50% efficient. This is why the Prius tries to use only something like 20% of the top-end of the battery's capacity, where it's more like 80% efficient. Now that's not only a waste of energy, it's also a lot of useless extra weight to be lugging around.

So if the engine is 35% efficient, generator 90%, battery 80%, motor 90%... that's down to 22.7%.

You'd be much better off, in my opinion, using an engine that gets good efficiency at low revs and/or throttle positions, using variable valve actuation, and a good efficient continuously variable transmission that allows the engine to run at full throttle as much as possible (vary power output by selecting engine speed as much as possible. And it doesn't have to be a cone-and-belt CVT before anybody mentions it). Use a large battery by non-hybrid standards, but small by hybrid standards, possibly 24V.

With a good regenerative breaking strategy and a supercapacitor, the motor/generator need not function as a generator quite as much. A stop from 30mph could potentially power your car's electrical systems for about 2 minutes, depending on what you've got switched on. The motor could be used to assist the engine so that less fuel is used to produce the desired power (use electrical power where available in preference to increasing the rpm, but never exceed in total the power the engine can produce on its own), but it makes no sense to drive around on the motor alone.

[kikiturbo2]

I am not talking about motor-generator-electric motor system... but rather a car with conventional drive + electric motors... best would be a combined generator/motor combo in the flywheel.. where you use the internal combustion engine in the conventional manner and electric motors to give extra go at the lights. Of course, you would charge the batteries by regenarative braking + IC engine if needed.. a continuously variable trans would be a plus, as you could run the engine at the point of highest efficiency for most of the time..

even better, instead of the batteries, you could use a high speed rotor, as it was tried on the patriot le mans car project..

the whole point is that instead of going for a normal sized IC engine + hybrid technology, we should use the smallest IC engine we can get away with, thus lowering the overall mass.... Cars like Prius are overly complex and not that efficient, when you take everything into consideration, mostly due to their mass..

[Moon Tricky]

Originally posted by kikiturbo2
the whole point is that instead of going for a normal sized IC engine + hybrid technology, we should use the smallest IC engine we can get away with, thus lowering the overall mass.... Cars like Prius are overly complex and not that efficient, when you take everything into consideration, mostly due to their mass..

Reducing the mass is always a noble aim. Cars have a lot of extra junk these days... electric windows... I can remember when winding a handle was good enough for most people, and you only got electric windows on real luxury cars.

Still, even though a motor might weigh less than an engine of the same power output, if its power has still got to come from the engine via an inefficient route including storage in heavy batteries, the advertised advantages seem like a red herring. Plus you don't just need full power to get away from the lights. You might want it for overtaking as well. 30hp might be just enough to do 70mph but it will struggle to reach it, and if you want to get 30hp out of the motor at the same time for the full 60hp, that's a lot of power you have to store up. And what if you don't have that much power stored up? That's why I'd prefer a 60hp engine and a 20hp motor, and a floored accelerator gives you 60hp -- whether it comes out of the engine or the engine and the motor together is up to the computer -- but that 60hp should always be there when you want it, irrespective of what the battery has been doing. You don't want to put your foot down and for nothing to happen.

Also the other thing is, top speed is relatively unaffected by the mass of the vehicle. Reducing mass improves acceleration, but at higher speeds, wind resistance becomes significant, and that's only a function of the shape of the vehicle, not its mass. I wouldn't want to go on the highway with anything less than a guaranteed maximum of 80hp, and anything under 120hp would be a bit of a chore.

[imaginesix]

Originally posted by Moon Tricky
I don't believe so at all... the only hybrid technologies I consider particularly worthwhile are regenerative braking and, if it could be done effectively, idle-stop. Unless batteries start getting a lot more efficient very quickly, I don't think converting engine power into electricity is going to do very much. Think about it, any power coming out of the motor via the battery and the generator is going to have a well-to-wheel efficiency of less than the engine on its own.

That's why the spicy (as opposed to mild?) hybrid should be configured to drive the wheels directly from the IC engine, when cruising. The large electric motor should be ideal for the accel/decel cycles.

But the Volt, as a stepping stone, would be interesting to try anyways.

[McGuire]

If things work out I could see how a deal like the GM BAS mild hybrid system (Saturn Green Line etc) could catch on across the board. You can have start/stop and regen braking -- free energy, basically -- in a plug-and-play module that will fit in almost anything. The retail price premium is about $2200USD as of today but that can come down with some volume and experience base.

[McGuire]

Originally posted by Moon Tricky
I wouldn't want to go on the highway with anything less than a guaranteed maximum of 80hp, and anything under 120hp would be a bit of a chore.

Goes to show how spoiled we are these days. I bought an Opel 1900 coupe (killer SCCA showroom stock car at the time) new in 1975. It was rated at 81 hp (Bendix EFI, '75 only) and was considered fairly sporty at the time. Top speed 94 mph. I once drove it from Detroit to Los Angeles nonstop with the pedal on the mat the whole way. (Well twice actually, also drove it back.) Nice little car.

[Zoe]

Originally posted by Moon Tricky


Reducing the mass is always a noble aim. Cars have a lot of extra junk these days... electric windows... I can remember when winding a handle was good enough for most people, and you only got electric windows on real luxury cars.

I don't know where the weight of modern cars comes from. A co-worker of mine owns an Audi S8; the curb weight is about 1900 kgs. Compared to my 1979 Cadillac Coupe de Ville this is not noticeable less; and this Cadillac has all possible gadgets (electric everything etc), no single piece of Aluminum on the body, a larger engine, a heavy frame, railroad tracks in the doors as side impact protection and whatnot.

Zoe

[Todd]

Originally posted by Zoe


I don't know where the weight of modern cars comes from. A co-worker of mine owns an Audi S8; the curb weight is about 1900 kgs. Compared to my 1979 Cadillac Coupe de Ville this is not noticeable less; and this Cadillac has all possible gadgets (electric everything etc), no single piece of Aluminum on the body, a larger engine, a heavy frame, railroad tracks in the doors as side impact protection and whatnot.

Zoe

----------------------------S8---------------Coupe de Ville
Airbags---------------------8? 10?----------------0
Differentials-----------------3---------------------1
Camshafts------------------4---------------------1
Wheel size------------------19"-------------------15"
Navigation system-----------1(80lbs)--------------Exxon Map(2 ounces)
Speakers--------------------10-------------------4
Sunroof---------------------1(huge, glass)--------maybe a mailslot
Doors------------------------4--------------------2

I would also argue about structural integrity and what not, but I've seen what an old body on frame full sizer can do to a new unibody German luxury sedan. Also, keep in mind that the 1979 Cadillac was a down-sized econo version of what came before 1977.

[phantom II]

80lbs for GPS ???? Try 5lbs including antenna and cable. 6 of those speakers are mid range and 2 tweeters. Caddies 4 speakers were huge. The caddy steel wheels and big radials must be at least 10lb more each than the Audis high tech wheels and tires even without the wheel covers. The Audi is all aluminum. Beats me why it weighs so much. Those two extra differentials must be heavy as hell. My neighbour has one. Audi engine weighs 430lbs. Porsche AWD weighs 80lbs more than the TWD 997. Porsche 997 engine, 444 lbs.
C6 Z06 LS 7 engine complete with ancillaries and flywheel and clutch 458 dry 490lb wet. Lots of oil.
LS 1/2 459lbs. The LS2 plus T56 tranny in my roadster weighs 582 lbs as a unit.
Those huge mid 70 Caddys don't weigh any more than the new DTS and STS cars.
BMW M5 V10, 529lbs
Carrera GT V10, 472 lbs.
BMW V8, 463lbs, L6, 409 lbs
New cars are heavy especially in the US. There is a story in this weeks Autoweek about Americas pitiful drivers. Now there in lies the problem, forget the heavy doo dads.

Originally posted by Todd


----------------------------S8---------------Coupe de Ville
Airbags---------------------8? 10?----------------0
Differentials-----------------3---------------------1
Camshafts------------------4---------------------1
Wheel size------------------19"-------------------15"
Navigation system-----------1(80lbs)--------------Exxon Map(2 ounces)
Speakers--------------------10-------------------4
Sunroof---------------------1(huge, glass)--------maybe a mailslot
Doors------------------------4--------------------2

I would also argue about structural integrity and what not, but I've seen what an old body on frame full sizer can do to a new unibody German luxury sedan. Also, keep in mind that the 1979 Cadillac was a down-sized econo version of what came before 1977.

[imaginesix]

Sound insulation (tar mat all around the cockpit and thicker window glass) accounts for a lot too.

[Todd]

Originally posted by phantom II
80lbs for GPS ???? Try 5lbs including antenna and cable. 6 of those speakers are mid range and 2 tweeters. Caddies 4 speakers were huge. The caddy steel wheels and big radials must be at least 10lb more each than the Audis high tech wheels and tires even without the wheel covers. The Audi is all aluminum. Beats me why it weighs so much. Those two extra differentials must be heavy as hell. My neighbour has one. Audi engine weighs 430lbs. Porsche AWD weighs 80lbs more than the TWD 997. Porsche 997 engine, 444 lbs.
C6 Z06 LS 7 engine complete with ancillaries and flywheel and clutch 458 dry 490lb wet. Lots of oil.
LS 1/2 459lbs. The LS2 plus T56 tranny in my roadster weighs 582 lbs as a unit.
Those huge mid 70 Caddys don't weigh any more than the new DTS and STS cars.
BMW M5 V10, 529lbs
Carrera GT V10, 472 lbs.
BMW V8, 463lbs, L6, 409 lbs
New cars are heavy especially in the US. There is a story in this weeks Autoweek about Americas pitiful drivers. Now there in lies the problem, forget the heavy doo dads.

I doubt that the Cadillac's wheels and tires weighed as much as modern fashion rims, and I've hoisted all of them. Big dumb rims rarely weigh as little as stamped steel wheels the same size, let alone stamped steel wheels sized for function instead of 'style.' The Cadillac's speakers may have been 4x10s and 6x9s, but they had magnets that wouldn't hold a Domino's coupon to your refrigerator. The navigation weight estimate was based on the difference between a Civic Si with navigation and one without navigation. Ask Honda why they can't make one that weighs 5 lbs.

The 1976 Cadillac Sedan deVille weighed 5,129 lbs, and rode on 235/75R15 tires. Do the new Cadillac sedans really weigh over 5,000 lbs? Does any tire fitted to a German car that is imported today weigh as little as a 235/75R15? The wheel and tire package on my 2007 Civic almost certainly weighs more.

[Todd]

Originally posted by imaginesix
Sound insulation (tar mat all around the cockpit and thicker window glass) accounts for a lot too.

That's fine, but the Cadillac would have had a silent interior until the window rubbers all dried out and the various mounting gaskets collapsed allowing everything in the interior to rattle like a new Audi TT.

[Moon Tricky]

Originally posted by McGuire
Goes to show how spoiled we are these days. I bought an Opel 1900 coupe (killer SCCA showroom stock car at the time) new in 1975. It was rated at 81 hp (Bendix EFI, '75 only) and was considered fairly sporty at the time. Top speed 94 mph. I once drove it from Detroit to Los Angeles nonstop with the pedal on the mat the whole way. (Well twice actually, also drove it back.) Nice little car.

The first car I ever drove was a 998cc Nissan Micra, 65bhp... it could do 70mph... heck, I almost got it up to 100 once. Took a while though... You can apparently turbocharge that old thing up to about 85bhp, however silly it may sound. Although I would guess 120bhp or more ought to be possible out of a 998cc engine, considering the Mitsubishi Lancer Evolution FQ400 gets 400bhp out of a 2.4L engine.

I think what I'm saying is, there are ways to make lighter engines with plenty of power, that don't involve big electric motors and batteries.

[imaginesix]

Sure but then you're shooting yourself in the foot when it comes to fuel efficiency, which is what this discussion is about. And in the case of a hybrid, especially one with stronger regen, light weight is of even less benefit than on a non-regen car. So not having to worry as much about weight is yet another benefit of having a more powerful motor and a minimal engine.

[Moon Tricky]

Originally posted by imaginesix
Sure but then you're shooting yourself in the foot when it comes to fuel efficiency, which is what this discussion is about. And in the case of a hybrid, especially one with stronger regen, light weight is of even less benefit than on a non-regen car. Yet another benefit of having a more powerful motor and a minimal engine.

A certain amount of turbo actually increases fuel efficiency, I thought. I'd always supposed the reason you didn't generally get them on small cars was the expense. Certainly, a lighter car will have less kinetic energy to recover, but then again, you'd have to put less back again to accelerate it, so it shouldn't really make that much of a difference.

[Greg Locock]

"A certain amount of turbo actually increases fuel efficiency, I thought."

Not on a typical gasoline engine

[McGuire]

Originally posted by Todd


That's fine, but the Cadillac would have had a silent interior until the window rubbers all dried out and the various mounting gaskets collapsed allowing everything in the interior to rattle like a new Audi TT.

This pains me to say as NOBODY loves old Cadillacs more than I do, but those old boats do not compare to a modern luxury sedan for interior noise levels and ride comfort overall. They just don't, by any set of metrics you can devise.

A body-on-frame car goes over the bumps like a stack of dishes, and the NVH issues are approached accordingly. A unit-construction car is many times more rigid. If I were updating one of those old Caddies perhaps the first thing I would do is figure out a proper way to weld the body and frame together and make a unibody out of it. Looking that over right now as a matter of fact. New frame would be the easiest way to do it, it appears.

[Zoe]

Count me in for the lovers of old American Iron.

It is a bit unfair to compare a 25+ year old car with one that's max two years old. I can compare my "old" Cadillacs to the new Mercedes that many co-workers drive. The main differences I see are:

* In most new cars one tends to sit cramped like in a camping toilet, regardless whether it is a Mercedes, BMW or whatnot.

* Speed performance. Any modern car (well most of them) go past 100mph without effort, which - while possible - is not really the case with Ye Olde Iren

* Fuel efficiency. Well, a Mercedes S-Class probably doesn't use that much more fuel than my Cad, but it goes faster with the same consumption!

I don't agree with the rattle and clang issue; to my experience a well kept body-on-frame actually performs smoother over rough roads than the modern "stiff suspension" cars. The body will kinda float, that's right, but there are country roads here where I will drive faster and much more comfy with my Cad than with any modern A, B, C, or whatever class Mercedes. Simply because the suspension is much more soft.

Same with engine noise. Tractors, aka Diesels are quite popular here, and when you drive along in a very expensive Mercedes Diesel, you still here the tractor under the hood making lots of noises.

I won't even start on seating comfort.

YMMV of course, and certain road applications demand different cars (or setups). I wouldn't want to drive all those twisty mountain passes we have here with my Cad, otoh I wouldn't want to drive my Supra over those LA freeways either

I don't know about the wheel weight as I never put one on a scale, however simply from a feeling the wheels of my Supra (205x60x15) weigh less than the ones of the Cad (235x75x15). They are smaller in any case.

Still, my question is really unanswered: Where does all the weight go to? To complete Todd's table:

----------------------------S8---------------Coupe de Ville
Airbags---------------------8? 10?----------------0
Differentials-----------------3---------------------1
Camshafts------------------4---------------------1
Wheel size------------------19"-------------------15"
Navigation system-----------1(80lbs)--------------Exxon Map(2 ounces)
Speakers--------------------10-------------------4
Sunroof---------------------1(huge, glass)--------maybe a mailslot
Doors------------------------4--------------------2

Engine size-----------------4l----------------------7l
Aluminum in car------------plenty------------------zero
Weight of bumper-----------20kg------------------60kg (per piece, estimated)

Not to forget that many gadgets like cruise control etc. are simply a leightweight electronic unit on a modern car, whereas it is heavy metal with plenty of vacuum hoses and cables, heavy electrical motors etc on a classic car (cruise control for example).

I would have hoped that with all those modern materials, like carbon fibre plastics, aluminum everywhere, cars should weigh much less instead of much more.

Zoe

[Moon Tricky]

Originally posted by Greg Locock
"A certain amount of turbo actually increases fuel efficiency, I thought."

Not on a typical gasoline engine

No? That surprises me. I mean, comparing a small turbocharged engine with a slightly larger one of the same power.

[crono33]

i have a completely new and unheard of idea about the idle-stop problem.

improve infrastructure to accomodate traffic and avoid jams, queues etc...

[desmo]

Or spend the money you'd spend on road infrastructure improvements in congested urban areas on making mass transit a viable alternative and consciously make the auto commuting responsible for most urban congestion as impractical and unattractive a proposition as possible.

[Todd]

Originally posted by desmo
Or spend the money you'd spend on road infrastructure improvements in congested urban areas on making mass transit a viable alternative and consciously make the auto commuting responsible for most urban congestion as impractical and unattractive a proposition as possible.

Seems that even pro mass transit types concede that commuting by car has to be artificially hindered to make other means competitive. It is perverted to the extreme that they would want to put such evil into practice.

[desmo]

I wouldn't call deciding not to invest the billions spent on adding lane miles in congested urban areas "artifically hindering" any more than I'd call not investing the same sums in mass transit instead "artificially hindering" that.

Euro cities with extremely limited traffic in urban centers and good mass transit are really pleasant places to be compared to car dominated cities in my personal opinion. Cars are a great way to travel outside these few urban centers.

[McGuire]

Originally posted by desmo
I wouldn't call deciding not to invest the billions spent on adding lane miles in congested urban areas "artifically hindering" any more than I'd call not investing the same sums in mass transit instead "artificially hindering" that.

Euro cities with extremely limited traffic in urban centers and good mass transit are really pleasant places to be compared to car dominated cities in my personal opinion. Cars are a great way to travel outside these few urban centers.

Right on. When you are sitting in a traffic jam four lanes wide and a mile long, nearly every car carrying one passenger, you have to ask yourself if this is an intelligent use of our civic space and natural resources. When are we going to stop? When we have paved over the entire continent?

[Todd]

Originally posted by McGuire


Right on. When you are sitting in a traffic jam four lanes wide and a mile long, nearly every car carrying one passenger, you have to ask yourself if this is an intelligent use of our civic space and natural resources. When are we going to stop? When we have paved over the entire continent?

Uh, don't sit in the traffic jam if you don't think it is a worthwhile way to spend your time.

[crono33]

actually, taking a short flight on a small airplane, you will quickly notice that roads cover really a tiny, tiny part of the available space, even in urban areas :-)

"roads everywhere" is usually the point of view of a motorist :-)

but yes, those traffic jams are silly. however, is very difficult to make people give up their personal transport. i have lived in dublin, ireland, where the city administration has been for over a decade very busy trying to discourage people from using cars. the result? a mess. traffic is a nightmare, made worse by the hundreds of empty buses further clogging the little space available...

even in switzerland, where the public transport works like a dream, only 11% of swiss use PT, and at peak time the railway network is full to the brim and couldnt accomodate any more convoy.

the solution to traffic congestion requires a mix of solutions: more parking places (in many european cities over 50% of urban traffic is people driving around looking for parking), efficient public transport, park&ride areas, cheap taxies, remote work, moving offices out of city, increase speed limits, etc

criminalizing drivers and forcing them on PT wont work. i think i saw a traffic jam made only of taxi, in NYC :-)

Originally posted by McGuire


Right on. When you are sitting in a traffic jam four lanes wide and a mile long, nearly every car carrying one passenger, you have to ask yourself if this is an intelligent use of our civic space and natural resources. When are we going to stop? When we have paved over the entire continent?

[Moon Tricky]

It really does astound me that it seems about 90% of cars on the road are carrying no-one but the driver. You'd think there would be a market for small, two-seater commuter cars, but no... people just wouldn't take them seriously, I don't think. Although Smart managed to sell some.

Still, it occurs to me that regenerative breaking and idle-stop would be ideal on buses. They're heavy and they do a lot of stopping and starting.

[McGuire]

Originally posted by crono33
actually, taking a short flight on a small airplane, you will quickly notice that roads cover really a tiny, tiny part of the available space, even in urban areas :-)

Yes, and the people look like ants and the cars like tiny toys. Maybe there is a more accurate and useful point of view available. How wide is an eight-lane highway including the safety aprons, medians, access roads, and exits and entrances? How much drainage area does it represent?

Basically we are snaking a quarter-mile-wide blight through the landscape. A flyover at 5000 ft is one way to look at an urban highway. Have you ever walked one?

[McGuire]

Originally posted by Todd


Uh, don't sit in the traffic jam if you don't think it is a worthwhile way to spend your time.

Now that is just a willfully stupid response. Go sit in the corner.