Don't tease the diesels

I've been mocked for suggesting HYBRID diesels. They clearly aren't receptive to change yet... especially when you bring up the topic of real-world data, knowing the new emission requirements cause an efficiency reduction. And they aren't too thrilled when I bring up the 1,200 mile road-rally, where the 2 Prius got better MPG than the diesel. The higher price of diesel obviously doesn't sit too well with them either.

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Im not so concerned about whether jetta owners are upset about diesel as I am that all of our goods and food is transported on trucks and trains fueled by diesel. Efficient yes, but expensive and not getting better any time soon!

 

I'm not going to mock you, but in my non-expert opinion, diesel hybrids have two things going against them:

Diesels historically do not lend themselves well to frequent on-off cycles. They do not start or stop smoothly. This is why people often complain about diesels idling too much - it can be a pain to stop and start them up

Also, diesels engines tend to be heavy, which increases the challenge for running on electric motors in a full hybrid.

I know diesel technology has come a long way, but I am not sure that they are the most compatible match for sharing a powertrain with an electric motor.

As I said, I am definitely NOT an expert at this, and my knowledge of diesels is decades out of data. So I invite someone with more knowledge to prove my biases wrong.

 

I little top-heavy, don't you think?

 

You know, if I've said it once, I've said it a thousand times....diesel hybrids already exist, and they're in use this very second moving goods around this country and around most other countries. We just don't ever think of them as hybrid vehicles, but all modern (think roughly 1950 through the present) railroad locomotives, except maybe the yard slugs, are hybrids. The diesel engine is used to generate electricity which is used to turn traction motors on the wheels.

They do in fact get phenomenal fuel economy (see for example http://www.aar.org/getFile.asp?File_id=364.) Yes, it's an industry publication, but the numbers aren't considered to be controversial.

Regenerative breaking is another thing that came from railroads. Modern diesel-electrics all do it (called dynamic breaking), the difference is what happens to the juice generated. Locomotives generally don't store the electricity in a battery, they either use it or dissipate it as heat.

It should be fairly easy to translate all the experience into a diesel truck with or without batteries. Heck, the Volvo C30 that's still in development is taking a page straight out of the railroad book. If I understand it correctly, all the motive power comes from four traction motors (one on each wheel, just like a train). The ICE simply drives a generator.

Diesel hybrids don't have to be that ambitious, but we shouldn't be too far from them. I only wish something could be done about the particulate exhaust issue.

 

I'm not in the least interested in a diesel engine. The diesel proponents very conveniently ignore the higher NOx and PM10/PM2.5. They also like to pretend that diesel exhaust isn't a proven carcinogenic or that it contains dioxin

 

[gasp] you mean you didn't statistically *test* for outliers?

 

The big problem with Big truck hybrids is weight. Trucks are limited to 80,000 pounds total weight including the trailer(s). Any added weight will decrease the weight they can carry, for less profit. Also keep in mind you would need a very large electric motor--our diesel in the motorhome makes 1350 lb-ft of torque--any idea what size electric motor you would need to equal that? Then you would have to work out the details of the transmission--I doubt an HSD would work at that scale, and still be weight-efficient.

 

The newest diesel-electric trains are starting to offer battery storage as an option.

Another place where diesel-electric hybrids have been common for years are ships. Almost all WWII era submarines, most new tug boats, ice breakers, and other working vessels use or used diesel-electric systems.

Tom

 

Diesel particulates are not a known carcinogen, ALL vehicle particulates are known carcinogens. Current diesels that utilize particulate filters can have official PM numbers of 0, just like gasoline engines. They don't really have 0 PM, they just reduce the PM size below what is measured by the standard just like gasoline engines. As far as official numbers though, you are living in the past. Diesels and Gasoline engines are equal in emissions, 0 PM.

Of course you don't really think your Prius has 0 PM emissions do you? A quick swipe of your finger inside your tailpipe will prove that theory wrong.

Now diesel NOx is higher than in a gasoline engine. This is directly related to the higher combustion temperatures due to higher compression. This higher compression in the primary reason that diesels have better mileage than gasoline engines. As gasoline engines get more efficient and use higher compression ratio's they are running into NOx issues as well.

 

That would be a real feat! I'm guessing that means that they've made some inroads into the charge density/weight issue. I always thought that the lack of the ability to store energy produced by regenerative breaking was a major flaw and sad to watch all that energy dissipated as heat. On the other hand the battery necessary to capture it was impractically large and correspondingly heavy.

I'd frankly be happy to see the current railroad technology transferred to trucks and the like while they work out the problems with storing electricity for use downstream.

Nobody said they have to put HSD in diesel trucks on the first go. I'd just like so see them use the fuel that they burn more efficiently.

 

No, I do not believe my Prius has zero emissions. No current internal combustion engine does, or will

However, diesels produce *far* more particulate and NOx emissions, even with a DPF. If you can find issue with the following, please let me know

http://www.toronto.ca/health/pdf/de_technical_appendix.pdf

http://www.toronto.ca/legdocs/2002/agendas/committees/hl/hl020729/it004.pdf

Subject Top Page: The Report on Diesel Exhaust

Subject Top Page: Diesel Programs and Activities

More Californians Killed By Diesel Pollution Than Homicide

Sick of Soot: Solutions to California's Diesel Pollution

Diesel Engines and Public Health

The last one compares the proposed T2B5 with the "strict" EuroIV and proposed EuroV diesel emissions standard. Quite a difference

http://www.ucsusa.org/assets/documents/clean_vehicles/dieseldilemma_fullreport.pdf

 

Diesel has more power per gallon then gas. I think its almost 20% more power. If they could make a hybrid that had a diesel engine powering an electric motor and also had regen it would be a winner. If the diesel engine runs at its most optimal rpm range to power the electric motor it could be made to be very efficient. You could also use the diesel engine for direct drive if the extra power was needed.

The car would probably get 75+ mpg and maybe 100+.

 

Frankly, I reject your challenge; it is simply a pointless rhetorical device.

The question isn't the science, it's the spin and the way the science is being used.

Let’s not loose track of reality.

No one here is claiming that diesels are "clean", but then again no one here is claiming that burning gasoline is "clean". If we want to continue living in the 21st century, then we're going to have to find ways of using our resources more efficiently. That includes diesel.

When you have divested your life of all the things that are touched by the use of diesel (in any form), you can make your argument legitimately. Until then, it's just a bit more than a little hypocritical to be sitting in your comfortable 21st century, first world life complaining about evils of diesel.

How many of the things in the room you're sitting in as you're reading this got to you on a truck, boat, or train (that includes the materials that the building is made of, your computer, and goes right down to your underwear)? How many of those things are you willing to do without (including the computer that you're going to rebut this on)?

Enough said.

While you may not care about diesels, you still benefit from them and you should be glad that there are folks out there trying to make better use of that particular technology. Can they do better? Yes. Should we be actively looking for and developing alternatives? Yes!

Should we be imitating the ostrich and sticking our heads in the sand? Well, you can if you want, that’s your right. I for one will be keeping my head up and my brain fully engaged. We need options and we need a bunch of them. We’re not going to get out of this with a one size fits all solution.

Peace.

 

Do you have any EPA diesel tests showing 0 PM for the current test?

The last TD number I looked at was for the 2006 Jetta TDi and the EPA test showed 0.046 for the PM.

 

No I don't because the EPA has not release the emissions data for the 2009 TDI yet. However, particulate filters have been used for years in Europe. Here is the results from the UK's equivalent of the EPA. Same car, different engines:

2008 BMW 123d with particulate filter:
VCAcarfueldata.org.uk - Search Results - Further Information

Fuel: Diesel
Fuel Consumption: 5.6 (l/100 km)
CO2: 148 (g/km)
Noise: 68.0 (dB )
CO: 0.385 (g/km)
HC: 0.023 (g/km)
NOx: 0.186 (g/km)
Particulates: 0.000
Euro Standard: IV



2008 BMW 125i Automatic:
VCAcarfueldata.org.uk - Search Results - Further Information

Fuel: Gasoline
Fuel Consumption: 7.9 (l/100 km)
CO2: 190 (g/km)
Noise: 74.0 (dB )
CO: 132 (g/km)
HC: 0.053 (g/km)
NOx: 0.045 (g/km)
Particulates: (N/A)
Euro Standard: IV