Talk:Fuel efficiency

message: I think everyone here has probably heard the apocryphal story about a guy who found a way to make a Camaro get 150 mpg with some secret technology but the big oil companies "silenced" him. Well I have no idea how much truth there is to this, but Wikipedia would be a great place for anyone who has a clue as to the truth of this to spread the word. If there is indeed a technology like this that would truly piss off the oil companies, let's post it up here and there will be nothing they can do about it.
:There is no truth to these stories, of course. There's only so much energy in a gallon of gas, and since the fuel economy of a car is dominated by factors OTHER than the engine (namely the weight, transmission and body shaping), nothing you can do to the engine is going to quadruple your gas milage. These stories are urban rumors that gain currency with the current "sticker shock" price of gas; they were huge in the 1970s for instance. Maury 22:51, 7 March 2006 (UTC)
replies: text: Getting 150 mpg isn't so difficult. Highly experimental vehicles have been able to get fuel efficiencies in excess of 1000 mpg for a few years now. I think the scepticism comes from a misunderstanding. You're not going to get a heavily laden SUV driving at 90mph to be very fuel efficient. But if you get a small to medium sized car there are things you can do.
Weight Minimise all the weight inside the vehicle, that means stripping out the seats, no luggage, go naked, lose weight, remove all the internal trim from the vehicle
Engine Get it cleaned and tuned up, use the most appropriate engine oil, etc. I'm not an expert in car maintenance, but there are small things you can do.
Driving Drive at around 55mph in the highest gear. Use the clutch when going downhill, and re-engage when you're near the bottom of the hill--Manc ill kid 12:09, 8 June 2006 (UTC)

text: As an aside to this debate, I find it interesting that the article states that a 'suitably modern supermini' may achieve something like 57mpg (UK) at 56mph... when my last car was a 1991 model that achieved close to 60mpg at that speed (when I could bring myself to drive that slow - normally mid 30s to low 40s - still, nearly as good as a Prius in the raw), was shaped like a box, and had a pig-simple engine (save for the single point fuel injection, more or less an electronically controlled carburettor) and a 4-speed gearbox... it wasn't fast, but it was quick enough to keep up with and regularly overtake motorway traffic. Does 'suitably modern' mean from 1980 onwards (approximately when the model line was birthed)? My current 1998 car with half the mileage, I haven't had opportunity to properly test, but I know I get notably worse economy in similar conditions (low to high 30s... fair play, it is a larger engine and slightly heavier, but it's got more sophisticated management, smoother shape, more and taller gears, etc)... are we slowly drifting backwards on this point? I'm reminded by the story of someone who had a Peugeot 205 diesel in the mid 80s that would regularly do more than 70mpg whilst still having (borderline :) acceptable performance... and this wasn't modified or anything out of the ordinary, but in fact fairly close to (and worse than) the manufacturers claims. Nowadays we need something with 3 fewer seats, minimal luggage capacity, dodgy handling and probably minimal extra performance to achieve the same thing? (Smart CDi)... or 1 less seat, similar get-up-and-go, and a suite of trick electronics and transmission? (The sadly discontinued Lupo 3L - it would, at least, have been more efficient around town - itself derived from an early 80s far-less-tricked-out design that pushed close to 80mpg in realworld testing). Gaaaah. People may speak of a conspiracy... I'd be inclined to agree with them. The technology advances we've had in 25 years SHOULD have given us the 150mpg, or at least the 100, by now... - Tahrey, 13/1/07 —The preceding unsigned comment was added by 82.46.180.56 (talk) 22:13, 13 January 2007 (UTC)
replies: text:  I also find the comment about achieving near 60MPG in a modern minibox. My 99 Corvette gets above 40MPG at 55-57mpg,a car I might add that is not designed for great fuel economy. If a modern econobox can't achieve better than 60MPG at those speeds, something is wrong IMO.
Ucntcme 03:16, 5 November 2007 (UTC)
thread_title: Fabled 150 mpg technologies

message: I have just asked a question about the format of fuel efficiency units at: Talk:Gallon. Bobblewik  (talk) 13:00, 20 Jun 2005 (UTC)
thread_title:  Ambiguous gallons in 'mpg'. 

message: I think this is incorrect. The best fuel economy is if you accelerate to the most fuel-efficient speed (45-60mph) smoothly but quickly, shifting gears to keep the engine RPMs up near the maximum of the torque curve until you get to speed. Google on "ecodriving". I'm not clear enough on my engine physics to be 100% sure on this.
=== More on "accelerate as gradually as possible" ===
Years ago, Car and Driver Magazine reported on some tests by BMW that measured the net amount of gas required to get from A to B, instead of the momentary use-fluctuations at different rates of acceleration. C&D reported this: For distances of a mile or more, accelerating at about 2/3 acceleration and holding steady at the desired speed yielded better gas mileage than slow acceleration to the desired speed. Volumetric efficiency was cited in explanation.
--- In the city, brisk acceleration has a collective benefit.  Even when the distance to the next light is short, moving smartly through an intersection allows more cars to get through, eliminating one or two go-stop-idle cycles for them. Obviously, there's a trade off here, but those who prefer gradual starts ought to be informed of the costs of their preference to others. 
--- Since heavier vehicles with larger cross-sections are more efficient at lower speeds than lighter vehicles with smaller cross-sections, it might make sense for SUVs, minivans, larger pickups, and crossovers to be included in the highway left-lane ban for trucks, using a height criterion.
(apologies--this may show up twice--new user) Bo8ob (talk) 20:45, 15 June 2008 (UTC)
thread_title:  "accelerate as gradually as possible" 

message: Years ago, Car and Driver Magazine reported on some tests by BMW that measured the net amount of gas required to get from A to B, instead of the momentary use-fluctuations at different rates of acceleration. C&D reported this: For distances of a mile or more, accelerating at about 2/3 acceleration and holding steady at the desired speed yielded better gas mileage than slow acceleration to the desired speed. Volumetric efficiency was cited in explanation.
--- In the city, brisk acceleration has a collective benefit.  Even when the distance to the next light is short, moving smartly through an intersection allows more cars to get through, eliminating one or two go-stop-idle cycles for them. Obviously, there's a trade off here, but those who prefer gradual starts ought to be informed of the costs of their preference to others. 
--- Since heavier vehicles with larger cross-sections are more efficient at lower speeds than lighter vehicles with smaller cross-sections, it might make sense for SUVs, minivans, larger pickups, and crossovers to be included in the highway left-lane ban for trucks, using a height criterion.
(apologies--this may show up twice--new user) Bo8ob (talk) 20:45, 15 June 2008 (UTC)
thread_title:  More on "accelerate as gradually as possible" 

message: how about some info on those world records for fuel efficiency?  the experimental cars that get 10,000 miles to the gallon and so on. - Omegatron 14:30, July 17, 2005 (UTC)
:Difficult do do in a meaningful fashion though... what's a solar car get? Maury 22:51, 7 March 2006 (UTC)
replies: text: Solar cars use about 40 kWh to travel 3000 km at an average speed of 90 kph or so. You can debate how to turn that into mpg. I think the 10000 figure is about right for mileage marathon cars, also bear in mind they are travelling quite slowly.Greg Locock (talk) 03:42, 25 August 2008 (UTC)
thread_title:  records 

message: It might be best to set aside a whole new topic just for tips about getting better fuel economy out of vehicles.  
Another section might be dedicated to fuel economy 'mods' that (at least in theory) definitely work, versus the pure quackery that gets really popular when fuel prices spike a bit.
First off, "gradual" acceleration is just wrong, if "gradually" accelerating means you're staying in first, second and third gear longer, you may as well be pouring gas onto the street.  You can prove this to yourself with your car's built-in real-time mileage doohicky, or with a 'scanguage' gadget plugged into your OBD port and monitoring fuel consumption and real-time mileage.  The longer you spend in lower gears, the worse the mileage you'll get.  Shift toward the highest practical gears as quickly as practical, and then 'gradual' acceleration will win... once you're in 4th or 5th gear.
Also, it should be pointed out that though fuel economy is a fine goal, that we're still not in bad enough shape that you NEED to dump a perfectly good vehicle to save 10MPG with a new car.  To save even 10MPG, it could take a decade, even longer to pay off the difference in a new car and a car you already owned, even at $3 or more per gallon.  Of course, if you're talking trading a truck/SUV for a little car and a 30+MPG difference, then it could take less time than paying for the car to make up the difference with only a modest increase in fuel prices, especially if you have little or no 'equity' in a truck/hybrid you're making payments on.  The more you drive, the quicker any savings add up.
Potentially Expensive Fuel Savings:
1. Get a car that is fuel efficient to begin with.
2. When you get your efficient car, get a manual transmission.  However smart an automatic transmission's 'brain' is, it can't see the road ahead like you can, and it can't predict what gear to be in as intelligently, as a result. 
 
3. Get a car with real-time fuel consumption monitoring, or buy an add-on like a '[Scangauge]' to use until you've established the optimal driving patterns for your vehicle.
4. Don't get a car that keeps the A/C on all the time to keep the windows 'clear', or with 'climate control' that maintains a preset temperature without giving you explicit control to turn the A/C absolutely off, even with the vent fan ON.  
"Free" Fuel Savings:
1. Keep track of your fuel consumption.  A notepad and a pencil will do.  A simple log of odometer+how much gas you put in, with whatever accuracy the odometer and pump gave you.  You can't tell if you're saving gas if you don't keep track.  
2. Check your tire pressure often, keep tires inflated properly & balanced/aligned.  For safety AND economy.  "Once a month" is recommended for checking pressure, but you should make sure the tires are equally and properly inflated more often than that.
3. You don't need to "pull G's" when the light turns green, and you don't need to go the speed limit (or higher) right up to a red light.  
4. Time your arrival at lights so they will be green and traffic will be moving more often than not.  If they aren't 
going to be green when you get to them, don't be in any hurry to reach them, and you won't feel so bad.
5. Manual: Coast out of gear everywhere you can safely (and legally) do so.  It adds up quickly.  Most states make it an infraction to drive 'down-hill' in neutral, but it's usually your most economical gear for every other situation. During extended downgrades at highway speeds, many modern engines will shut off fuel supply completely.
6. Keep an adequate enough following distance that you can pace the car(s) ahead and virtually never brake or accelerate.  (The dimwit who tailgates you now would tailgate even if you were tailgating the car ahead, and driving 100MPH.)
7. Get into the highest gear you can, as quickly as you can when accelerating.  
8. Take a hill in the highest gear you can, even if it means going a little faster up-hill.
9. Off the highway, open the windows.  On the highway, at higher speeds, shut them, the aerodynamic drag is worse, possibly worse than running A/C.
10. A/C is "free" when rolling down-hill, in gear.  You really can live without A/C, with the vent fan on, even in 100+F temperatures.  Bring some water with you.
11. Don't go excessive speeds on the highway.  Don't go excessively slow, either.
12. Use the cruise control on flat, open highway.  Set a sane speed, and let the computer stick to it.
13. Don't treat your car as a mobile storage shed/dumpster.  Shovel the garbage and useless junk out of it once in a while.  It may even stink less.
14. Keep the windows absolutely sparkling clean and residue free, and you won't need to operate the A/C as much in damp weather to keep them clear.  You'll also be able to see better at night.
15. Don't drive around in parking lots looking for a spot.  Half the lot is almost always empty, so look in the empty half for your spot.
: Regarding #5: No, this is not a good idea in modern engines. Most will all but shut off fuel supply if the manual transmission is in gear and the clutch in engaged, but will have to add fuel to maintain idle speed if the engine is not being pushed along by the motion of the drivetrain from the ground up. In particular GM LS* engines are this way.  If you do have a manual, you can often save fuel by "winding it up" in a lower gear and jumping to a higher gear, skipping in between. By using fewer shifts you keep the motor running a constant rate of increase rather than ups and downs. this is, however, dependent on the power output of the car compared to it's weight and gearing. As the saying goes "Your mileage may vary".
:Regarding 12,this is also not true. Learning to manage you fuel speed by foot pressure is more effective. Cruise control systems today are designed to maintain a given speed, not maximize fuel economy. If you pay attention you will find they hunt and flux, trying to adapt to the slight changes in road surface. A constant use of fuel will lead to better economy even though your speed may vary within several units of measurement.
:Regarding 14, this is also not true. 
:Air conditioning is not needed to keep windows from fogging over air flow works fine, and a clean window will fog over as much as a dirty one. Oh and on anything with a V-8 A/C is essentially free. All accessories combined (which means power steering and power brakes, alternator, etc.) account for less than 2.2% of the energy draw from the engine.
:#8 is also questionable as bogging an engine will allow to to do it, but dump fuel and increase emissions to do it. It can also cause excessive engine wear and tear as well as cause issues on the driveline.
:Regarding tire pressure ,even pressre is not a given. Depending on alignment, road crowning, and tire/wheel size, etc. It may be better to have front/rear air pressures vary. Further, there has been no conclusive research that shows that even tire pressures across have any effect on mileage. What does matter is under-inflation. More tire surface on the ground means higher rolling resistance.
:Regarding #1, if you want to do this, make sure to note the temperature when filling, and always fill to where you can see the fuel. Otherwise you can see a difference of a couple gallons of gasoline which will throw your measurements all off.
:Furthermore, due to variances among stocks and rotation, energy content and quality of gasoline varies from tank to tank, resulting in as much as 15% variance in fuel economy with no changes to driving or other conditions.
:And as far as MPG based on speed, this is also not useful or generic enough to hold true. A vehicle's best MPG/MPH will depend on it's gearing. A vehicle that is geared to run at a lower RPM at 65MPH will get better economy than that same car geared to run lower at 55MPH, all else equal. For example, in my 6-speed I will get better economy in top gear at 65 than I do in 5th gear at 55. That means some cars or trucks may get better economy at 70 in high gear than 65 in a lower gear. For example, my Vette gets upper 40's on the freeway at 55 MG in top gear, but if a hill shows up that is not a short one, I am usually better off MPG-wise to drop to 5th than to let it lug at a lower speed in a higher gear.
:The single best thing you can do to get better economy in your vehicle is to learn to drive it under it's better conditions, and use the brakes as little as possible. That and don't drive in the rain (as much as 20% reduction). Modern "accelerate by wire" vehicles can see gains of 2-3 MPG across the board by learning where to rest the pedal when not accelerating.
Ucntcme 04:29, 5 November 2007 (UTC)
replies: text: As noted earlier, this blanket statement can lead to an increase in gas usage depending on the car/truck used and its gearing. There is nothing magical about speed. if you car is geared for 55 (older cars), the dropping to 50 can increase consumption. If it is geared for 65 (newer cars), then you likely will increase consumption. Also the comment about hills is so far off base it is astonishing. Maintaining speed up hills is a matter of sustaining motion, specifically momentum. A vehicle traveling at 65 has more momentum than one at 55. Thus, you are better off to start with more momentum up the hill. This is especially true for straight gasoline engines as they lose efficiency under load (E85 and diesel do not suffer this problem anywhere near as bad). Further, speeding tickets have no bearing on fuel economy. Ucntcme 04:29, 5 November 2007 (UTC)

text: Guaranteed way to eliminate a "speeding" problem: eliminate the crime of speeding. Seriously. It's an obvious point. May not be the best way to go for some, but the reality of it is that it would in fact eliminate speeding tickets. Ucntcme 04:29, 5 November 2007 (UTC)

text: 9 and 10, beginning in the late 1970's there was a shift away from heavy and inefficient AC compressors that looked like lawnmower engines to smaller and more efficient types that use much less horsepower. Except for cars with the tiniest 3 and 4 cylinder engines put into cars too heavy for them, air conditioning has little to no impact on MPG. For vehicles where top gear is a 1:1 ratio, that's the most efficient gear, getting there as quickly as possible without 'lugging' the engine is the most efficient. A large part of the reason the EPA 'city' MPG is less is due to so much time spent in the lower gears, the other is time spent idling at stop lights and signs. If the transmission has an overdrive gear (where the driveshaft in RWD or the last gear before the differential in FWD is turning faster than the engine) that is the most efficient gear. For used cars, especially Ford and GM RWD models, it's often possible to swap a non-overdrive transmission for one with an overdrive. Unfortunately for Mopar lovers, they never made a RWD automatic with an overdrive (I dunno if they did manuals with overdrive). The easiest ones are before computer controlled transmissions, but even the "E" versions can be swapped, there are companies that sell reprogrammed computers for that.  —Preceding unsigned comment added by Bizzybody (talk • contribs) 04:07, 4 September 2008 (UTC)
thread_title:  Better Fuel Economy Tips 

message: Preliminary apology:
I apologize for the Wikipedia ineptitude displayed.  This is the first time I have been here.   I don’t know how to do this.
I found this on Wikipedia:
"Avoid driving at excessively low or high speeds. Most gasoline powered cars operate with maximum efficiency in the range of 45 to 60 mph ( 70 to 100 km/h ). This effect is largely due to aerodynamic drag. For vehicles with greater frontal area and less streamlined shapes (SUVs, trucks) best fuel economy is typically obtained toward the lower end of this range."
I think the above is garbage  I am a mechanical engineer.  I have some experience with automobiles, and I have driven one for many years.  Who writes this stuff?  Where is their data or theory?  How can it get changed?
What does "maximum efficiency" mean?  Is that distance per unit of fuel or is it 
distance per dollar including driver time and "My time ain't cheap?"
I think this is stuff written to justify wacko driving.
unsigned comment by Ecar 12:43, 23 September 2005
:Check out What speed should I drive to get maximum fuel efficiency? --Ben 03:26, 29 November 2005 (UTC)
thread_title:  I appolize for whatever ineptitude 

message: I think it would be good to work information about fuel economy trends into the article. Here's some stuff I found so far:
*EPA report Light-Duty Automotive Technology and Fuel Economy Trends: 1975 Through 2005 
*American Scientist article  Fuel Efficiency and the Economy (PDF)  (HTML or PDF, subscribers only)
--Ben 03:26, 29 November 2005 (UTC)
thread_title: Fuel Economy Trends

message: This page is really misleading and tries to express engineering principles and laymans terms. To summarise:
Fuel efficiency is simply useful energy output divided by heat or chemical energy input expressed as a percentage. This can be calculated for any thermal plant e.g. power stations IC engines etc. It is affected by a number of factors depending on the thermal cycle and machinery used.
Depending on which camp you're in, fuel economy is the amount of fuel required to go a fixed distance (l/100km) or the distance which may be travelled for a fixed amount of fuel (mpg).
Specific output is the power output per unit displacement.
These there measures are separate and NOT related! However, factors which affect one measure may well affect another.
The efficiency page needs to be totally re-written so that it contains actual facts.
Yotboy.
192.149.117.69 13:25, 2 January 2006 (UTC)
thread_title:  Thermodynamics 101 

message: Added external link to text "93/116/EC"
:... European Community Directive 93/116/EC. 
-Mardus 11:38, 8 January 2006 (UTC)
thread_title:  Section: Fuel Economy 

message: *Separated links that take to sites/pages commissioned by various governments' institutions
: I wasn't quite sure as to how necessary it was, but since I noticed that they could be grouped like that, then I thought, why not, and one of the reasons would be that the number of links was such that like links could be grouped together.
:Only that I grouped them into sections, which immediately reflected in the Contents bar at the top of the page, as a very long section title significantly extended the Contents bar's width. So I changed code to remove sections, but keep the whole section's appearance.
*Wording...
:Added the above link (in "Section: Fuel Economy") to External Links section, with a link description (which is the title of the directive) referring to another directive, which I also linked, but didn't place to a separate line, perhaps for the sake of brevity.
:The link looks like this: 
::*European Community Directive 93/116/EC — European Commission Directive 93/116/EC of 17.12.1993 adapting to technical progress Council Directive 80/1268/EEC relating to the fuel consumption of motor vehicles
:— The problem there is repeated text "European Community Directive 93/116/EC" and "European Commission Directive 93/116/EC" and that extends the whole area containing the link and its description. 
:I would delete "European Commission Directive" part placed after the link, but I am not sure then as to the wording of the actual link, as section Fuel Economy contains reference to "European Community directive", while the actual directive says it's a "European Commission Directive" in its text.
:The question boils down then (if the repeated part were deleted) to whether the Directive would be referred to as a "..Community Directive" or a "Commission Directive".
-Mardus 12:20, 8 January 2006 (UTC)
thread_title:  Section: External Links 

message: This article could be usefully expanded - it shouldn't just be about cars. Interesting questions are: Why are some engines more efficient than others? How do different types of engines compare (Deisel, Fuel Cell, electric, etc)? How do cars compare with aeroplanes, ships, rockets, steam engines, human body, etc for efficiency? How (in detail) has the efficiency of engines improved over the centuries?
There should also be short introductions and links to topics like aerodynamics as it pertains to fuel efficiency. This article is not a specialised topic and should be in layman's terms. I imagine that, with energy issues being so in the news lately, a lot of people will come looking for information on fuel efficiency. Seabhcán 11:17, 2 February 2006 (UTC)
replies: text: Perhaps it would be better to restrict the comparation to modes of passenger transportation from one point to another of the Earth surface. Comparison with the Space Shuttle is meaningless. Also it's not fair to compare cars with humans (either walking or cycling) because the form of energy they use is not interchangeable. StefanoC 12:43, 23 February 2006 (UTC)
thread_title:  article expansion 

message: Please keep it to third person. The idea is to inform the reader, not tell the reader what to do. That's Wikibooks' job. Elle vécut heureuse à jamais (Be eudaimonic!) 05:20, 13 February 2006 (UTC)
thread_title:  This is not wikibooks 

message: Naturally aspirated engines tend to be more fuel efficient than engines with forced induction (ex: turbocharged, supercharged).
From the little thermodynamics and engine theory I know, this statement seems incorrect. Turbochargers use waste energy in the exhaust to presurize the intake, thereby overcoming throttling losses (which are about 15% at cruise power). Whereas in a normally aspirated engine the pistons have to suck air into the cylinders, using up real power, a turbocharged version of the same engine would have no losses to this suction, and get that energy for free.
Can someone illuminate?
Maury 22:42, 7 March 2006 (UTC)
thread_title:  Ummm, is this actually right? 

message: It's not fair to compare the miles/gallon of the Space Shuttle with those of cars and trains (that don't have to work against gravity). One more meaningful measure would be fuel consumption vs. potential and kinetic energy gained. StefanoC 08:45, 13 March 2006 (UTC)
replies: text: I added it more as a piece of trivia, rather than a serious comparison. Seabhcán 10:57, 13 March 2006 (UTC)
replies: text: Yet it could be interesting to show how much (in)efficient rockets are with respect to other engines or to, e.g. a Space elevator StefanoC 13:15, 13 March 2006 (UTC)
thread_title:  Efficiency of rockets 

message: Fuel efficiency is not expressed in terms of power per unit of engine displacement. Meggar 01:09, 5 April 2006 (UTC)
replies: text: That section should be substituted perhaps with a discussion of theorical limits (Carnot efficiency) and a general description of the relative efficiency of open vs. closed cycles, otto vs. diesel, gas vs. steam. StefanoC 14:42, 5 April 2006 (UTC)
replies: text:  Yes, that is what should be here. The entire paragraph starting with the premise is incorrect. Deleted. Meggar 02:27, 23 May 2006 (UTC)
thread_title:  accuracy tag 

message: There has been no comment on this on either page in the month since the tag was put up. Here is one for Oppose. PS, tag removed by another user. Meggar 01:48, 27 July 2006 (UTC)
thread_title:  merge with Fuel economy in automobiles? 

message: For some reason,  has removed the fully referenced data in the energy content table and replaced some of it with less reliable online sourced information. This has also left some parts of the table entirely empty. The fact that he doesn't personally have access to the industry standard reference manual from which the data was taken does not justify removing data that wiki, by definition, considers more reliable. I haven't reverted his edit this time, but I do believe that it is actions such as his that undermine the fundamental validity of wikipedia. --Athol Mullen 21:17, 9 March 2007 (UTC)
thread_title:  Removal of properly referenced data 

message: The C-Train in Calgary, Alberta, Canada is entirely offset by a wind farm south of the city.  —Preceding unsigned comment added by 208.38.1.1 (talk) 20:33, 18 September 2007 (UTC)
thread_title:  Other trains 

message: To me the article implies that the increase in energy content is responsible for the majority of economy differences between gas and diesel. The clear dominant factor is the 50% better efficiency - extracting more energy from the source material. Clearly, 10% more energy in the fuel can not produce a 40% increase in economy, but getting half again as much out of the fuel certainly can. Anyone up for improving the wording there, or shall I? Ucntcme  —Preceding comment was added at 04:35, 5 November 2007 (UTC)
thread_title:  Diesel Vs. Gasoline 

message: In a related matter, does anyone think that fuel economy should be kept out of the automobile infoboxes?  Please voice your opinion at http://en.wikipedia.org/wiki/Template_talk:Infobox_Automobile#Vote_on_Fuel_Economy_in_the_Infobox 198.151.13.8 (talk) 18:28, 7 May 2008 (UTC)
thread_title:  Fuel Economy infobox 

message: CCPP with natural gas have 58% efficiency in electric power production. New planed CCPP should even exceed 60%.
The only car known by me in all versions is the Renault Kangoo. Here a study about the efficincy with gasoline, diesel, natural gas and electric power version Cleanova 2. --Pege.founder (talk) 10:19, 30 May 2008 (UTC)
thread_title:  CCPP and electric drive outperforms any ICE in efficiency 

message: Why haven't the numbers for E85 (85% Ethanol, 15% gasoline) been added to the chart?  —Preceding unsigned comment added by Bizzybody (talk • contribs) 04:10, 4 September 2008 (UTC)
thread_title: E85?

message: Is there place for methane in the table?
According to http://www.littleredbook.com/fuels.html methane has 23,875 Btu/lb  —Preceding unsigned comment added by 89.79.66.46 (talk) 09:53, 7 September 2010 (UTC)
thread_title: Methane as Fuel

message: Substituted at 15:41, 29 April 2016 (UTC)
thread_title: Assessment comment

message: In India only kilometres per litre is used. We don't use any other system  — Preceding unsigned comment added by 14.141.84.194 (talk) 18:15, 20 May 2016 (UTC)
thread_title:  In India only kilometres per litre is used 

message: As of August 2016, merger of the engine efficiency article into the fuel efficiency article would probably work well, if anyone wants to spend the time. I may do it sometime if the spirit moves me. — ¾-10 01:45, 12 August 2016 (UTC)
replies: text: Both of these are very broad terms. We should have them, because an encyclopedia needs something under those terms. A real article, in a real encyclopedia, would be much more specific. We need (i.e. these are massively important topics in today's world) much more specific articles in addition, such as engine fuel efficiency for current road vehicles, for petrol vs. diesel vehicles, for aircraft, for railways and diesel vs. electric. The way to move gradually towards such in-depth coverage is not by starting to merge the very top-level articles. Andy Dingley (talk) 10:29, 12 August 2016 (UTC)
thread_title:  Merger would probably work well 

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thread_title:  External links modified