Porkyd
Jan 21, 2010
2:01 PM

It always seems to be the eternal argument and unless a diesel hybrid comes along, which should smash all records, we'll never know.

I'm in the UK and gone from a 2.2 Diesel to the Prius Hybrid for various reasons, MPG being one of them. There's lots of diesels out there that will claim to do 70-80mpg but the one I had struggled to do 40mpg and Id had it for three years since new. I suspect a lot of the diesels that claim to do high MPG are just the small cars (Polos, Fiestas in the UK - not sure what's in the U.S.). The Prius is classd as a medium sized family car over here. If they did the same set up in a little mini car I suspect they could get some astounding MPG figures.

The battries don't need replacing every few years, you don't have to plug them in and as far as I am aware the production of the batteries and their effect on the environment have come on a long way since they first started to produce this type of battery. At the end of the hybrids are just another option for the motorist day.

I suspect if you drove the Jag XF diesel doing 0-60 in 5.9 seconds from every time you stopped you might not get 51mpg out of it.

Everyone will have an opinion but there's no right or wrong answer and I'm as much against eco campaingers plugging the hybrid as the saviour of the world.It's just a car with a petrol engine that just happens to have a battery that helps it out now and again!

VWJunky
Jan 22, 2010
5:06 AM

I am partial for Diesel here in the US but we don't have the killer little diesel cars that get the great fuel milage. I would think around town the hybrid would win hands down but on a long haul accross he country the diesel would be king. Trains are Diesel Electric and are pretty effiecent. I think in the near future that diesel and electric will come together and give is crazy good MPG. I really want the jeep wrangler 4 door hybrid with the diesel generator. But it won't happen. oh well.
Erick

There is also something else that the Europeans get with their diesels: dirtier emissions. Current passenger car diesels have to meet Tier II bin 5 if they're being sold in the USA, and they're just barely making that. Current Euro 5 standars are less strict. But once Euro 6 standards hit, watch the European diesel MPG numbers go down.

Draigflag
Jan 22, 2010
10:06 AM

I never understood the emission regs in the US. For example, i saw a 6.2 litre V10 diesel truck over there, now are you seriously suggesting that a truck that gets 12 MPG and has high C02 emissions, emits less N0X than a tiny European diesel that gets 120 MPG?

I know C02 and N0X are completely different, but surely a car that emits up to 5 times less C02 is surely not going to emit more N0X than a truck 5 times it's size?

European standards are very strict indeed, but they're different to US ones, hence why there's so much confusion and misunderstanding and why they're hard to compare directly. If you look at the Euro 5 standards for Europe, you can see that passenger cars (diesel) must emit only 0.080 grams per kilometre of N0X, but if anybody can compare that to US ones as i am struggling to find any N0X measurements for US passenger cars!

Notice I said "passenger car." Trucks are in a completely different class. In the USA, not only do they not have as strict emission standards, but they also have much less strict CAFE standards. It's a big mess that should be change in a few years.

Draigflag
Jan 23, 2010
2:51 AM

Well either way, the fact that boats and planes (the biggest polluters) are exempt from any kind of carbon taxing in the EU just shows that governing bodies are just taxing people for the sake of it!

The 16 largest ships in the World create more pollution than every car in the World, and yet in the UK we are expected to pay between £35 and £400 a year in carbon taxes for our cars, even if we only drive a few miles a year...

And then the government wonders why we have little faith in them!

You mean I have to raise my faith level to 'little' ?

It is a little strange. Over here you can drive a PZEV vehicle for thousands of miles before emitting as much pollution as using a lawn mower for one afternoon.

Something that everybody should be conscious about when comparing fuel mileage between European and American cars is that the gallons used are different.

Therefore:

1 MPG (UK) = 0.83 MPG (US)
1 MPG (US) = 1.2 MPG (UK)

A 50 MPG car in Europe only makes out 41.5 MPG in America. The metric L/100km doesn't suffer from this, but I think more people are comfortable using miles and gallons. Just be careful when you're talking to someone across the pond that you're both speaking the same "language".

Draigflag
Jan 26, 2010
9:51 AM

Yes i am aware of that, but a car that does 126 MPG, still does roughly 100 MPG, a car that does 82 MPG still does 68 US MPG etc. It's about the only thing in America that's smaller is the gallon! :)

There's no doubt at all that a diesel car has the potential to be considerably better than a petrol/hybrid.
In response to Porkyd and his comments on the false claims about diesel cars, I've run an Audi A2 1.2Tdi 3L for 7 years now. The A2 isn't much smaller than a Prius and probably has much better use of space and, therefore, capacity. It's certainly not a small car.
My A2 averages between 90 and 96mpg (UK) and has given me 120.2mpg (UK) on a door to door trip from my home in Yorkshire to London - including the town driving at either end. I can very easily exceed 100mpg on any long run.
Show me a Prius that can match that!
The (very) sad thing is that my 7 year old car (a model only sold in Germany) was discontinued by Audi some years ago because "no one ever bought them" and "they never made any money on them". In fact, they didn't charge enough money for them. I bought mine in Germany for 3000 pounds less than the standard A2 was on sale in the UK. There doesn't seem any will within the motor industry to tackle the emissions problem. the technology's been around for years but I'd place a bet on the new A2 (coming in 2011) having much poorer consumption figures than my 7 year old car with 105,000 miles on the clock!

I went from a Peugeot 2.0l HDI 110hp to a PriusIII > 130hp and I consume less gas than I used to consume diesel.
And you shall not forget that one litre of diesel rejects more CO2 than the same amount of gas, so that the difference in CO2 is even more important.
But what is nasty with small diesels is that they often do not have particulate filters nor NOx filters, and this is an issue in cities where diesel cars are really a nuisance (not so on highways, but who does only highway driving with his car?).

Draigflag
Feb 22, 2010
12:06 PM

I'm still confused by all this N0X stuff, if you look at the N0X emissions for Europe, they are so much lower than in America. And most cars have DPF fitted as standard.

My only guess is that because fuel in the US is so "dirty" and unrefined compared to the liquid gold we make in Europe, that somehow when a clean Euro diesel is tested in the US with US diesel in it, it somehow emits more N0X as there are more harmful pollutants in the US fuel to start with.

VWJunky
Feb 23, 2010
5:42 AM

We just lowered the sulfer content in Diesels here in the US a few years ago. We had to that first before we could use the new emmisions that are now on the cars. So I don't know how dirty our fuel is now compaired to Europe but it should be alot closer to you. Here in the US we refine diesel here and send it to Europe! LOL!

ryrym1984
Mar 1, 2010
6:59 PM

I don't think diesels can achieve much else beyond a small niche market share here in the US. Our emissions controls just don't allow the automakers to bring small diesels to market. Given the governmental controls most automakers will continue down the hybrid route this side of the Atlantic.

VWJunky
Mar 2, 2010
9:05 AM

The smaller cars don't have to have the expensive Urea treatment, VW's jettas and Golfs don't need it but if you get into larger engines you will need them. I won't go hybrid at all unless it comes with a diesel motor! LOL!

BDC
Mar 2, 2010
11:07 AM

The fact that diesel produces about 15% more CO2 than gasoline (gallon for gallon burnt) means that a 40mpg TDI Jetta produces about as much CO2 as a 34mpg Corolla. A 55mpg Prius emits about 40% less CO2 per mile than a 40mpg TDI Jetta. CO2 restriction is where most civilized nations are heading with emissions controls, that will play a large part. The extra expense of a diesel engine is the other barrier -- though I don't see how VW can justify the price of German/Mexican Corollas, diesel or no diesel.

I would love to see anyone sell a diesel microcar in the US. It might fail miserably like the Smart car has, but it might be mildly successful too. I would think about buying one. But not a 60hp diesel four-door that goes 0-60 in 15 seconds like the A2. That would never sell here. I am looking forward to the American version of the iQ. That's a car I'd consider buying, as long we get the 1.3l and a manual transmission.

VWJunky
Mar 3, 2010
10:33 AM

I pull a small trailer with my jetta and still get in the 40's mpg on the highway. I can get 32mpg pulling a 13 ft boston whaler with 4 people. For me Diesel can do more and I love the power at 1200 rpm and that is with my old 01 Jetta that is not clean. I just don't like the Prius. Pretty much boring to me. I can hop up the power on my car with cluch ripping force and still get the same milage. Power and good milage is what I like! LOL! There are going to be different cars for different people and peoples needs. Still wanting a Jeep Wrangler 4 door with Diesel and would go hybrid if they do decide to go with the diesel hybrid!

Draigflag
Mar 3, 2010
11:15 AM

You're all forgetting about the new strict Euro emission standards, diesels are getting cleaner and cleaner and more powerful. Last time i researched this, i found that the N0X emissions have been much lower in Europe for years than in California, by around 5 to 6 times, and i triple checked my calculations too. I think the controversy surrounding this and all the confusion can only lead to one conclusion - the US has developed a conspiracy theory that somehow a tiny clean efficient diesel car from Europe that does upwards of 100 MPG can somehow emit more N0X than an 8.0 litre Yank tank that barely reaches double figures!? C'mon guys, common sense needed...

VWJunky
Mar 3, 2010
11:59 AM

I am with you Fiat500! Now if we can get the Fiat 500 Diesel here!

Draigflag
Mar 3, 2010
12:05 PM

You'll want the new one then, now with 95 HP and even lower emissions! Should do over 80 MPG easy! Or maybe Fiats revolutionary Mutiair engines? Power/economy or better still, Fiats new 0.9 litre 2 cylinder engine available in the 500, less than 100 grams of C02 per kilometre but around 120 MPG and it's turbocharged! The choice is endless...

But the Fiat 500 is going to the US next year or maybe the year after

Ignore the manufacturers claimed figures when looking at diesel mpg. Real world figures are invariably a lot less. Even driving them "like a Vicar" its hard to get close to the claimed combined figures.

The hybrids real world economy seems a lot less than the claimed figures too. As the other poster says, thats before you take into account battery replacement costs. More over, battery costs are likely to harm residual prices of such vehicles, thus increasing the overall cost of ownership.

The figures on this website for both diesels and hybrids make interesting reading.

BDC
Mar 5, 2010
3:28 PM

I don't know where fiat500abarth's "120mpg" figure comes from for the future 900 twin. They are saying mileage will be 15% better than the 1.2l which gets something like 55mpg (US) in combined driving.

That said, the EPA figures for diesels here in the US are pretty accurate.

But I agree, Rob, one of the reasons I use fuelly is for real-world numbers from real people driving production cars. The EPA has started falsely inflating American cars (see Ford Fusion Hybrid or Chevy Equinox EPA ratings), so any shred of accuracy they had before they merged with the American auto industry is suspect. Ever since they started messing with the ratings in 2007 they've been off, and now that they're exercising a major conflict of interest they are even further from the truth. I get my EPA ratings from Fuelly :)

Draigflag
Mar 6, 2010
3:22 AM

Yes i understand it's hard to get the claimed figures as they are achieved under very controlled environments. My Abarth 500 claimed figures of 51 MPG which i've had once or twice but i really had to try hard to get that! It only averages around 31 MPG in the real World.

Getting back to my original argument, i still think Diesels are better than hybrids, the main reason is the fact that you can often have performance as well as economy in most cases. Did anybody see the test Jeremy Clarkson did with the Prius V's the BMW? He followed a Prius around the track being driven hard, he was in a gas BMW V8, the Prius got 17 MPG whilst the BMW got 19 MPG. I rest my case...

Both hybrids and certain common rail diesels have "ships on the horizon", in terms of future maintenance costs. Currently, the lowest running cost option (in high fuel tax countries) is probably an LPG converted petrol. Lower exhaust emissions too.

ryrym1984
Mar 11, 2010
8:05 PM

A lightweight car with an engine able to loaf around at track speeds vs a weighty car with a tiny engine >.<>
Diesels won't make it here unless we change the EPA regs. Or new technology comes around that makes it cheap to work around them. VW small diesels have to waste fuel in regen cycles to to burn up particles. All other diesels need the urea fills. I'm not sure how many buyers are going to want an Accord that starts at $25,000 and needs a $300 urea fill every 7500 miles or so.