http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/ Autoblog Comments for BMW 520d beats Prius in gas mileage http://www.autoblog.com/media/feedlogo.gif http://www.autoblog.com en-us Copyright 2008 Weblogs, Inc. The contents of this feed are available for non-commercial use only. Blogsmith http://www.blogsmith.com/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/
Time to start thinking. Ugly and slow Prius, or fast, brilliantly shaped 5 series, hmm...]]>Mar 23rd 2008 12:12PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/
This test is proof that you can alter the conditions of any situation to get the outcome you desire. So a diesel gets good mileage on the highway. No surprise there. Too bad there are so few diesel cars in the U.S. and the fuel's outrageous.]]>Mar 23rd 2008 12:33PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/
First, BMW is much more expensive.

Second, why did they only add 100 miles urban driving? Just felt pity for Toyota? If 460 miles were driven on BMW's strong point, then at least 350 miles should have been driven on Toyota's strong point (urban).]]>Mar 23rd 2008 12:42PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/
Diesels can give you better mileage without making you feel like you're sacrificing your driving experience in some world-saving crusade.]]>Mar 23rd 2008 1:01PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/
If you're comparing diesel vs gas hybrids, you need to take into account the additional energy-per-liter/gallon, and you need to look at CO2 emissions.

The fact that the Prius had significantly better CO2 emissions is an important stat.

The end result is: they're both great cars, they have different advantages, and they serve different purposes.]]>Mar 23rd 2008 1:19PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/
I would love to have a BMW diesel, don't get me wrong, but the Prius still has that crown as an affordable "green" car that gets good gas mileage with midsized car room and hatchback versitility.
]]>Mar 23rd 2008 1:39PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/
"Diesel contains about 10% more energy by volume than gas and therefore produces about 10% more CO2 by volume when burned."

Just to clarify: diesel contains more energy because it weighs more. It weighs more because it physically takes more crude oil to make a gallon of diesel than a gallon of gasoline: depending on estimates, it's between 15-25% more crude per gallon.

Then there's the high-strength block, high-pressure injectors, turbocharger and emissions control system. Granted, not quite as complex as a parallel hybrid, but not as simple as a naturally-aspirated gas engine, either.

Compression ignition is a good technology, but I think there's a bias amongst gearheards towards diesel, and it's one that conveniently glosses over the true fuel requirements and complexity inherent in a modern TDI.

]]>Mar 23rd 2008 3:59PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/
While diesel engines are more expensive to manufacture for the reasons you mention, hybrids of course also add complexity. In addition, the diesel, properly maintained, should provide a more consistent level of performance over it's lifecycle than will a battery-assisted gasoline engine (which won't be reaching the same mileage numbers after 100k-200k miles).

There's tradeoffs for both. And this is really an apple-oranges comparison since the 5 series isn't really in the same size or price class as the Prius. I don't think many people are going to be cross shopping a $45k+ mid-sized sedan against a $24k compact.]]>Mar 23rd 2008 4:48PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/Prius 65mpg (imperial), 109g/km
118d 62mpg (imperial), 119g/km

I'd bet that under a real world test the 118d would substantially beat a Prius. The offical figures for a 520d are:
55.4mpg (imperial), 136g/km

It must be noted that the co2/km figure is calculated from the combined cycle fuel economy figure so any test that over states economy will understate co2 emissions.]]>Mar 23rd 2008 7:16PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/Mar 23rd 2008 9:36PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/Mar 25th 2008 3:58PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/Mar 23rd 2008 12:13PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/Mar 23rd 2008 12:53PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/Mar 23rd 2008 1:19PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/
It's not a US thing, it's a chemistry thing and no magic is going to change it.

Note that if didn't crack or polymerize any H-C-Hs that you get from oil, you would indeed get more Diesel from a barrel of oil than you do gas. But those days are a long way behind us now. Modern Diesel isn't just bunker fuel anymore. As Diesel emissions standards have become tighter, the requirements for the fuel itself have become tighter, and now Diesel requires a lot of reprocessing, just as gasoline does.]]>Mar 23rd 2008 1:29PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/
For explanation, here is a portion of Csaba Csere's article from Car and Driver, April 2008;

"AI Mannato, a fuel-issues manager at API, explains that oil refineries tend to fall into two categories: catalytic cracking and hydrocracking. Most U.S. refineries are set up for catalytic cracking, which turns each barrel of crude oil into about 50-percent gasoline, 15-percent diesel, and the remainder into jet fuel, home heating oil, heavy fuel oil, liquefied petroleum gas, asphalt, and various other products. In Europe and most of the rest of the world, refineries use a hydrocracking process, which produces more like 25-percent gasoline and 25-percent diesel from that barrel of oil. So the rest of the world is already maximizing diesel production. In fact, despite using a refining strategy that minimizes the production of gasoline, Europe still ends up with too much of the stuff, so it exports it to America-about one of every eight gallons of gasoline that we consume.

Meanwhile, Americans are already using most of the diesel fuel
that our refineries produce, so if sales of diesel cars take off, keeping the diesel flowing here will put further demands on tight worldwide diesel supplies and probably cause the price to rise even more. "]]>Mar 23rd 2008 5:22PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/
Cracking and polymerization is what you are talking about, and I already addressed it. With some additional reprocessing you can break apart the molecules in the oil and make other ones from it. If you want more kerosene (jet fuel), you can get it.

But you also end up with less of something else. There's no free lunch. No part of a barrel of oil is wasted in the US or in Europe, so if you start looking for more of one thing, you give up something else.

And again none of this makes up for the fact that Diesel contains more H-C-H chains in it, and so you have to use up 15% more of the H-C-Hs from oil to make a gallon of Diesel instead of gas.]]>Mar 23rd 2008 6:03PMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/
Read my post again. Try to understand it. Get back to me in the morning.]]>Mar 24th 2008 2:32AMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/Mar 24th 2008 10:31AMhttp://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/http://www.autoblog.com/2008/03/23/bmw-520d-beats-prius-in-gas-mileage/Mar 23rd 2008 12:29PM