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August 29, 2012


This is because Environmentalists (Eco-Marxists)don't really want alternative fuels; they want reduction in consumption and government control (and redistribution) of natural resources. This is why they oppose nuclear energy, shale, fracking, clean coal, etc while favoring cap-and-trade, carbon taxes, etc.

Half, you need to get into international motor racing. Audi won Le Mans this year racing a diesel car. Europe is full-on with diesel technology. Audi's car also the epic Williams flywheel.

The downside to diesels is that they require strong particulate filters and ruin the engine note. So much of the raw sexuality and beastly nature of high performance vehicles is lost.

The greater the population, the less room for those of us who love adventure. The only adventure left is of the urban kind or sports, which aren't really an adventure. Car racing and private flying under assault. I guess that leaves sailing for the remaining adventure with climbing in there too. Otherwise bad-ass mofos are out of luck.

I always LOL when I see the plates on hybrid cars in Virginia - the motto is "Clean Special Fuel". Um, whut, it uses gas just like every other car...

Yet for some reason diesel does not count as a "Clean Special Fuel" and diesels don't get the privileges hybrids do (e.g., hybrids can use the HOV lanes even with one passenger) even though they have high mpg.

Small diesel cars are quite the rage in Europe.

The US seems to have missed out on the advanced diesel engines for cars; perhaps it skip that generation and go straight to the new petrol engines that combine low cubic capacity with both a turbocharger and a mechanically driven supercharger. I've seen some reviews of them recently.

Mind you, that's quite a bit of kit to go wrong and land you with heavy repair bills.

Remember that a gallon of diesel is more expensive than a gallon of gasoline. MPG is a truly worthless statistic. Vehicles should be measured on a $ / Mile basis.

Here's my understanding of the situation... Oil refineries produce equal amounts of diesel and gasoline. Most of the diesel refined in the US is shipped to Europe.

So switching the US to diesel would drastically increase fuel prices in Europe and create a huge gasoline surplus.

The thermodynamic efficiency of diesel isn't so much higher than gasoline-- diesels get better fuel mileage (volume of fuel burnt vs. distance) because diesel oil contains more chemical energy (it's denser).

Anyway, diesel engines are nice things and America could probably use more of them, but they are harder to start, produce more air pollution (and heavy tailpipe filtering reduces fuel efficiency), give less road performance (diesels produce more torque at low RPM's but don't run well over a large RPM range, so you either stick to a smaller speed range-- not so good in city traffic-- or haul around a more complicated transmission), and use a less convenient fuel (diesel oil doesn't evaporate readily so it gets all over hands and fenders and the ground and stinks the place up). Oh, and diesel engines weigh more per horsepower, so some of your fuel efficiency is sacrified to hauling the engine itself around-- they deal with that in Europe by just using small, low-horsepower engines, but Americans like peppy cars.

When you're paying ~$2/liter at the pump, be sure you'll look for a car with a decent mileage, let's say an average of 5.5l/100km (42mpg). It doesn't matter if it's gas or diesel, but mostly diesels fall into this category without being ridiculously small.

The other reason we Europeans buy diesel cars, despite being a little more expensive, is that the engines last longer, which translates into a higher resell value.

There is the preconception that diesel engines pollute more than petrol. Well, they pollute differently. Both engine types have to use filters and catalysts in order to conform with the tough emissions rules.

Also, some countries tax differently depending on the engine type and capacity. And speaking of engine capacity, I think most diesel cars have engines between 1.4l and 2l; gas a little bit lower.

"Vehicles should be measured on a $ / Mile basis"

Yes, but that changes over time. GGE/mile (GGE=gallon of gas equivalent) is a better measure, but my favorite for measuring alternative fuels is the EGG (Effective cost per Gallon of Gas equivalent). EGG values include the extra up front costs relative to a similar gasoline model.

Here are some EGG values for various alternatives:

natural gas: $2/gallon
Volt-hybrid: $10/gallon
Leaf electric: $12/gallon
Tesla: $15/gallon

So for the battery-only cars in production, gasoline would need to be over $10/gallon for them to be economically viable.


Diesel smells bad and reminds SWPLs of truckers, who are the wrong kind of white people.

The real conversation that should be had here is not diesel or gasoline (at present prices the diesel advantage is not large, and diesel cars are a bit sluggish), but natural gas.

Natural gas cars. That is the future, and the game changer. In the last couple of years it has turned out that the US is the Saudi Arabia of NatGas with fracking, so nat gas prices have plummeted and are now quite cheap.

Here are the advantages of NatGas cars:

(1) The energy is much cheaper
(2) You can get a pump to fuel you at home, using your residential natural gas.
(3) If you fuel at residential rates via (2) above, things are much cheaper still than you would even get at the pump.
(4) Natural gas is super clean, both in terms of conventional pollutants and lower carbon emissions.

Tons of buses and fleet vehicles run on natural gas, and natural gas consumer cars are increasingly common in Europe.

But natural gas consumer cars are very rare in the US and all you can get is the Civic CNG. And they make them really substantially more expensive, even though it is technologically almost the same as a gas engine. What's up with that?

The energy-equivalent cost of natural gas is about $1.55 so the equivalent of a gallon of gasoline.

With gasoline pushing $4, this is a huge difference.

One reason NatGas cars haven't been big 'til now is that natural gas used to cost 2x or 3x more than it costs now before the massive discoveries of the last couple of years.

Here's a good link to an article discussing diesel autos -http://www.practicalenvironmentalist.com/automobiles/2012-usa-diesel-cars.htm.

Diesels have advantages and disadvantages compared to gasoline engines. They are more efficient, and, in my state, diesel fuel currently costs about the same as regular gasoline - both just over $4/gallon (thanks, Barack!). So the greater efficiency of the diesel translates into real savings. Diesels have a higher compression ratio, so they don't need spark plugs or ignition systems and the engines last longer. They do require more frequent oil changes. In the past, diesels had the reputation for being hard to start in cold weather, but that problem seems to have been overcome. Some people think that they are noisy or smell bad.

The only diesel passenger cars available right now in the US are German imports - Audi, VW, BMW, and Mercedes. Of course, this is because autos with diesel engines are much more frequent in Europe, where diesel fuel is less expensive than gasoline. But both Ford and Chrysler currently produce large diesel pick up trucks, and apparently all three US manufacturers are planning to produce diesel cars in the next two years.

One thing I didn't realize was the main reason that diesel cars are so much more common in Europe than in the US. Here it is (from a link in the article I cited):

German automakers seem dead-set on exporting their “clean diesels” to the United States. However, to sell a diesel engine in this country, it must be equipped with an exhaust after-treatment system, and a special fuel injection system in order to meet our strict air quality rules.

European emissions rules allow a diesel to emit up to 0.29 grams of nitrous oxide (NOx) per mile — which is about what the typical diesel school bus or trash truck emitted 5 years ago.

US regulations on the other hand, only allow a diesel to emit 0.07 grams of NOx per mile, making compliance a costly effort.

Smaller firms like Honda or Subaru would have to spend hundreds of millions of dollars to develop a compliant engine, for a historically small US market. So it’s tough for many of them to justify such a big investment.

The Germans however, seem willing to take this risk. And if history is any indication, they’re the ones that can garner mass public acceptance for a new technology.

What the other Dan above says about natural gas cars is true. And with the flood of new natural gas coming from fracking, I don't understand why there is not a big movement in this direction.

One issue is that the unit to connect your home natural gas line to refuel the car is expensive. But natural gas stations are available in most big cities now, although they are in limited locations.

But if big government has to push some energy solution on us - wouldn't natural gas cars make more sense than solar, wind, etc?

Good grief! Diesel fuels are only about 10 to 30% denser than gasoline, depending on type.

The reason that diesel engines are more efficient is that they operate at much higher pressures and temperatures than do gasoline engines. The thermodynamic efficiency of any heat engine increases with temperature and pressure. This include coal-fired and nuclear electrical power stations.

The somewhat higher density and viscosity of diesel fuels is due to their higher content of long-chain molecules. This reduces their volatility, which is needed to prevent premature detonation (knocking) during the fuel/air compression stroke.

Speaking about natural gas as fuel (LPG - liquefied petroleum gas), there aren't too many models or makes to choose from, but...

Back in Eastern Europe (Bulgaria, Romania...) I've seen a lot of taxi drivers hauling big LPG tanks in their trunks. The modifications required for the engine were relatively easy and cheap to make, and it worked on most gas engines. Actually it worked better on simpler, older engines than on the more recent ones.

It was the only way a cab driver could make a decent profit, because LPG, besides being cheaper then oil products, was not taxed as much. What do you think the government will do if more people start using LPG as fuel for cars, not just for heating?

On downside of LPG is that it has less energy then gas (20-30% less).

[HS: I don't think we have enough NG to run every car--and then we'd use it all up and we wouldn't have any left for home heating. I don't think it's as good an idea as it sounds.]

I looked at buying a new car recently and the gas mileage difference between the VW TDI models (the models running on diesel) and non-diesel cars of the same size was not that large. Like 28 mpg vs. 34 mpg. Its not a miracle device.

The big difference comes from driving smaller cars with smaller engines. My old Saturn SL would get 42 mpg on the highway because it was so light and has a small engine.

For instance the diesel VW Toureg gets about 22 mpg which is pretty good for a mini-SUV, their premium gasoline model is 19 mpg and their hybrid model is 21 mpg (worse than the diesel).

I think diesel is a nice alternative, but 52.5 mpg will require a lot of people to buy Priuses and Volts.

Have you seen how much diesel fuel costs? That is the reason that diesel cars don't sell.

Back in the '70s, when diesel cars were everywhere, diesel cost far less than gasoline. That is not the case these days.

Lots of information and dis-information here. Have been driving diesel cars for 3 decades. A modern diesel really spoils you for a gas model. Lots of torque. Currently have 2 VW Jetta TDI's, getting 36 and 38 around town, 46 and 49 on the hiway. both have over 100,000 miles and run like new. Traveling in Europe I have driven a little Ford diesel, very nice and the Honda Whisperdiesel...incredible. diesel fuel is far less flammable than gasoline, the engines provide the same or better performance, much higher mileage, and they last a long long time.

Diesel, awd/rwd, under 3000 lbs, 6 speed, station wagon is the holy grail of SWPL gear-heads.

MC: Diesel smells bad and reminds SWPLs of truckers, who are the wrong kind of white people.

This is the reason they promote "green" alternatives that aren't viable and won't be for the foreseeable future.

The reason diesels don't sell well in the US is due to taxes. A few years ago the lefties demanded higher taxes on diesel because it was "dirty". Diesel has been improved so it's now cleaner than regular gas. But lefties don't want to remove the higher diesel tax because they want to force everyone to go to electric instead. It's the same reason they don't want natural gas. I figured that out when T Boone Pickens gave his "bridge fuel" speech at TED. Natural gas is domestic and cleaner than gas but the liberals were still bitching about it. As Voltaire said, "The perfect is the enemy of the good."

By the way, the Ford Focus Econetic has a regular gas engine and gets 67 mpg. But it's not sold in the US because Ford's marketing shows that not enough people will buy it to justify importing. You can't blame Ford for that. It's the consumers who won't buy it. Although if gas keeps going up I'd say that might change.

"The somewhat higher density and viscosity of diesel fuels is due to their higher content of long-chain molecules. This reduces their volatility, which is needed to prevent premature detonation (knocking) during the fuel/air compression stroke."

In a diesel, the fuel gets injected at the top of the compression stroke(near Top Dead Center), and keeps getting injected until the crank has turned to 20-30 degrees past TDC. This not only eliminates knocking on compression (there's nothing to knock) but keeps the pressure in the cylinder steady through more of the power stroke. (As the cylinder descends, more fuel gets added to maintain pressure.)

Contrast this to a gas engine, where compression has to be limited to prevent knocking, and where the entire fuel-air mix is burned as soon as the spark plug fires (near TDC). Pressure drops rapidly during the power stroke of a gas engine, limiting its ability to create torque.

This is why you have to "get on the gas" when towing anything with a gas engine. You need really high pressure at TDC, to get anything throughout the rest of the stroke.

I often roll my eyes at commercials showing gas-powered pickups towing heavy things. It's a good way to wreck an engine.

Albert Magnus,

If you go on TDI club, you will find plenty of people getting significantly more MPG than the official numbers. My wife's 2010 jetta TDI wagon, has a 16 gallon tank and usually gets 620 miles per tank of combined city/highway driving. Highway typically averages around 49-52mpg, city is closer to 35mpg. Driving style has a lot to do with it as well. The majority of Jetta's now a days sell as TDI models and they hold their value, ven e4th generation golf/jetta diesels are easily double the price of a gas model and have better MPG than the more recent ones.

You will find VW diesels that get way better MPG than that in europe, but they are on lupos and other small cars. Heck, the global market Ford Ranger gets 40mpg and its 90% of the size of a ford 150, AND makes 350 ft/lbs of torque. It also looks way better than the F150, comes with 6 air bags etc. We aren't getting it as they think it would canabalize f150 sales and that people would rather pay a lot more for a Ford Transit van...

Switching to diesel isn't a good long-term solution because the efficiency gains are not high enough to slow down oil consumption. Plus sufficient replacement of gasoline engines by diesel will take 15+ years.

I admit that battery technology isn't ready from prime time (lithium-ion batteries aren't quite practical for most people and it's not clear if Li-S or Li-air batteries will ever really work). Of course, batteries have the advantage of increased efficiency and the ability to draw energy from nuclear power.

Of course, nuclear plants (primarily thorium-fueled) could be used to make dimethyl ether, which could replace diesel, if we really want to go that route.

I get 47.5 mpg hwy from a 2001 VW bug w/ 275K miles on it. I drive from the Eastern Shore of MD to Pittsburg and Dayton regularly. I really don't understand why either the estimates I hear of diesel mpg are so low or why my actual mpg is so high. I must be doing something right.


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