Non hybrids get over 100 MPG now

[Draigflag]

Just been taking a peep at the most economical cars of 2014, the new Peugeot 308 takes top place with 91 MPG average, followed by the Renault Clio with 88 MPG average. As expected these are all diesel cars, no hybrid technology involved.

As mentioned, figures are for "combined" fuel consumption, this is the average which according to my previous cars, I've got very close to, even exceeded, on a regular basis. For the "highway" figure, I should imagine some of these cars do over 100 MPG, but I can't find any information on this. Never considered a French car in the past, but they certainly seem to be leading the way with fuel consumption.

http://www.nextgreencar.com/most-eco...l-diesel-cars/

[trollbait]

None of which are available in the US.

The combined numbers are from the NEDC test cycle. Which is very optimistic, more so than the pre-2008 EPA, and would likely require advanced hypermiling techniques to reach outside of the lab. The VW Golf with 2.0 TDI is rated from 60mpg to 69mpg(I'm assuming this is standard and not Imperial gallons) depending on transmission and trim. The EPA numbers are just 34mpg combined.
http://www.fueleconomy.gov/feg/Find....32698&id=32699

The EPA test does underestimate diesels, but even giving a best case 20% increase for that, the EPA numbers are still short by at least 20mpg. The best one on Fuelly is at 49mpg, with them averaging in the 38 to 40mpg range.

Since the 2008 changes, the EPA numbers have pretty close to what most report getting.

[Charon]

Even mopeds and very small scooters don't get that kind of mileage. Before I'd believe anything over about 50 mpg for anything, I want to see it tested by the likes of the American Consumer Reports or some equivalent, testing on real roads under real traffic conditions. The only reason I'd believe 50 mpg comes from the (now very old) VW Rabbit Diesel with manual transmission. That Diesel was pre-emission control. And it got its 50 mpg in the days of the US 55 mph speed limits.

[Draigflag]

Well as you say the Uk gallon is actually larger by around 17% I think, so 100 MPG, would be closer to 80 MPG in the US. You have to remember, fuel here is much more refined, which not only gives better fuel consumption, but fewer emissions, and more power too, so a car that gets 91 MPG in Europe, might only get 75 or 80 MPG using diesel from the US.

The figures quoted are average figures, I admit the Highway figures can be optimistic, but in all fairness, I've always got close to the average figure with my style of driving. I once got 82 MPG in my old diesel car which only had an average figure of 65 MPG, so it's not impossible to get these figures, even exceed them.

Im hoping to change my car soon for the 2nd most economical car in that list, so I will no doubt share my findings, watch this space!

[Draigflag]

Originally Posted by trollbait

None of which are available in the US.

The combined numbers are from the NEDC test cycle. Which is very optimistic, more so than the pre-2008 EPA, and would likely require advanced hypermiling techniques to reach outside of the lab. The VW Golf with 2.0 TDI is rated from 60mpg to 69mpg(I'm assuming this is standard and not Imperial gallons) depending on transmission and trim. The EPA numbers are just 34mpg combined.
http://www.fueleconomy.gov/feg/Find....32698&id=32699

The EPA test does underestimate diesels, but even giving a best case 20% increase for that, the EPA numbers are still short by at least 20mpg. The best one on Fuelly is at 49mpg, with them averaging in the 38 to 40mpg range.

Since the 2008 changes, the EPA numbers have pretty close to what most report getting.

That's because by the looks of things you only get the 2.0 litre diesel, there are lots of different versions available this side of the pond, the most economical is the 1.6 Bluemotion which does 94 MPG on the highway and an average of 88 MPG!

http://www.volkswagen.co.uk/new/golf...gine/1540/1542

[Charon]

I would also be interested to know in what way the fuel is "more refined" in Europe than in the USA. To cite a specific example, gasoline (petrol) is usually thought of as more refined than diesel, but because it is a lighter hydrocarbon it contains less energy per unit volume than diesel. In the US, #1 diesel (winter fuel) is more refined than #2, but yields poorer fuel mileage.

[trollbait]

Yes, we only get the 2.0 TDI here, but the NEDC numbers are still a bit higher. The 60 imp. mpg is 50 us mpg. The EPA gets 34mpg combined, and users on this site are closer to that number. A few do get near that NEDC number. A few also only get in the low thirties.

The EPA tests have their flaws, but the numbers on the window sticker are close to what to typical person will get. They also allow comparisons between vehicles. CR and other magazine tests do not control variable to allow that.

The gasoline is generally a higher octane overseas. Higher octane allows an engine to run a more efficient, higher, compression ratio. The 1.4L turbo in the Sonic and Cruze was designed for Europe. Because of the stigma premium fuel has, GM just says it runs regular and lets the knock sensors do their job. These engines will take advantage of premium if given the chance though.

I ran a tank of premium in the Sonic once. It felt like performance improved. The fuel economy did by 2mpg. With the 24 cent price difference at the time, it was a tiny bit cheaper per mile.

I understand that the diesel is a better cetane. I don't know much on the subject, but wouldn't be surprised if it allows the engine to run a bit more efficiently like higher octane gasoline does. I do know European diesel has more lubricants in it. When you hear of a German diesel needing a new fuel pump in the US, it may not be because of the part, but that we generally have crap fuels here.

[Charon]

According to Wikipedia - http://en.wikipedia.org/wiki/Octane_rating - there are several ways of rating octane. Research Octane Number (RON) and Motor Octane Number (MON) are most common in automotive use. RON usually runs several points higher than MON. In Europe the RON is commonly displayed on pumps; in the USA the average of the two is used and is usually 4 or 5 points lower. This may well explain the common thought that European gasoline is more refined when in fact the two are about the same.

Supercharged (including turbocharged) gasoline engines are still constrained by the fuels in use. Typically the engine will run a lower compression ratio so that when the boost pressure is added the cylinder pressures will not go too high causing detonation. Electronic knock sensors help, but retarding the timing to eliminate knock also reduces efficiency.

Naturally occurring hydrocarbon fuels (petroleum) usually contain sulfur. When the fuels are refined some of the sulfur is removed. When the US EPA started requiring low-sulfur fuels the refining process had to be changed, and the change also resulted in refining out some of the natural aromatics. Those aromatics helped lubricity, particularly in Diesels. Their removal caused a lot of problems with O-rings in fuel pumps. The latest round of sulfur reduction (Ultra Low Sulfur) is no doubt causing more, particularly in older engines. In effect, the more highly refined fuels are actually causing problems that do not happen with less highly refined fuels.

[Draigflag]

Well thanks for doing the homework, you obviously have more time than me! Perhaps then this explains why American cars require more frequent oil changes as there are less lubricants in the fuel to start with?

I know in times gone by, some 15 to 20 years ago, some people beleived that diesels were not allowed in the US due to N0X emissions. Its true that Europe seems more concerned about C02, but when you look at the new Euro emission standards, a lot of the new diesels have lower N0X emissions than some of the large gasoline cars in the US. Im just waiting to hear what excuses the US government can come up with next to prevent small efficient diesels being sold there.

[trollbait]

The Wikipedia article includes a table of octane ratings by the different methods for a large sampling of petrols. The "EuroSuper" or "EuroPremium" or "Regular unleaded" in Europe, "SP95" in France entry is around the US midgrade octane rating. Other European examples are higher than our regular. It is possible that the info is out of date or incomplete.

Mazda had to lower the compression rating of its Skyactiv-g engine from 14:1 to 13:1 in order for it to run on US regular.

Due to tightening emissions Europe has gone to the lower sulphur content. I wonder if current fuel pumps and such are designed with this in account.

While there maybe some anti-diesel bias at the EPA, the main hurdle to diesel cars in the US is their past reputations of being dirty, stinky, noisy, and slow. The last influx was in the 1980's. Emission ratings for them were several steps behind gasoline cars. They didn't have a DPF, or even a turbo then.

The diesels in GM cars then use the blocks of a gasoline engine, and had reliability issues. The only diesel cars available to most since then have been VWs, which had past reliability issues here. Mostly with things not related to the engine, but the timing belt likely kept some away from the TDI.

Encounters with diesel trucks owned by tuners that think billowing smoke is 'cool' leave many with a poor perception. I still remember one pick up with upright exhausts that you literally could not see from behind while accelerating up the highway. That was only last summer.

Many would be surprised that a new diesel is nothing like they heard or remember, and that they meet and in some cases exceed the same emission requirements for gasoline cars. I don't think we'll get the smaller diesels here, because many think a 0 to 60 mph time over 10 seconds is too slow.