I’m embarrassed to admit this, but I learned a lot from this Jalopnik article by Autombile editor Jamie Kitman.
I don’t care about the political part, or rather, I don’t care to discuss it here, but I am amazed by the studies he references.
I was in the dark on diesel.
My question is, is bio diesel just as bad?
https://jalopnik.com/the-big-diesel-lie-grows-while-the-trump-administration-1837177598
In reply to CyberEric :
It has to do with the combustion process. The same properties that allow good BSFC also send NOx through the roof.
If you want a clean Diesel, lower the compression, run it with spark ignition, and keep the combustion near stoich so it doesn't create high NOx. To do this, you'd need some way to restrict the intake at idle and low load, like a throttle body...
To clarify, is this the part you want to discuss?
A study published in the scientific journal Nature concluded that 38,000 additional people will die prematurely each year from diesels’ emissions of vehicles known to be out of compliance, added to 70,000 people that would likely die each year from diesel exhaust even if the vehicles met the letter of the law.
Yup.. https://www.ft.com/content/8e8fc06e-2b05-11e5-8613-e7aedbb7bdb7
It's a dirty fuel. and johnny coal roller ain't helping.
It takes more energy to create bio-diesel than you get by burning it, so depending on where that energy comes from it may be a losing battle no matter how much cleaner it does or doesn't burn (which i dont know) than 'regular diesel'.
But yeah, diesels are crap for the environment and always have been. However, there's a lot of ugly in the world to call out and my personal opinion is that lack of regulation and enforcement by governments is a far greater ill than the general existence and use of diesel fuel.
Interesting article!
Heck, if it runs on combustion it is bad for the environment.
In reply to Snrub :
That, and that although one outcome is reduced (CO2 I believe) the rest are far worse. I didn't know that.
In reply to Vigo :
Thanks for the info, that's a good point. And yeah, I'm just wondering if it burns cleaner.
Yeah, it was a compelling read for me.
Knurled. said:In reply to CyberEric :
It has to do with the combustion process. The same properties that allow good BSFC also send NOx through the roof.
If you want a clean Diesel, lower the compression, run it with spark ignition, and keep the combustion near stoich so it doesn't create high NOx. To do this, you'd need some way to restrict the intake at idle and low load, like a throttle body...
We should ground your comments. Yes, high combustion pressures = better BSFC = higher combustion temps = more NOx.
But from an engine out standpoint, a diesel NOx output is considerably lower than gasoline. So if the law allowed un-controlled exhaust emissions, a diesel is cleaner for NOx, HC, and CO, only higher for PM.
Thankfully for our health, that's not even close to be good enough.
And it's REALLY easy to clean up gasoline emissions when running stoich- which it does really well. And REALLY hard and expensive to clean up diesel emissions. Possible, but just so expensive that it's hardly worth it- as it adds many dollars on top of the already more expensive diesel engine.
Which is why you don't see nearly as many diesels in the US.
Ignoring Jamie's normal ranting and raving, that article is pointing out why the EU has gone to all on road driving certification, and why many of us (not officially by any means) expect California and the EPA to eventually do some on road emissions testing. So we are working towards far more robust solutions.
Not to comment at all about current solutions and robustness (again, I'm not offical either)- just that we see the possibility and want to make sure we are doing it right before the rules come down.
I take everything I read on Jalopnik with a grain of salt -- IMHO (as with most former gawker media products) they're much more interested in controversy and clicks than they are in truth and journalistic integrity.
AIUI, diesel combustion puts out more of some pollutants but less of others. Generally it's better on HC and CO, worse on NOx and particulates. I have also read (elsewhere) that the local impact of the different pollutants varies with the local temperatures/etc, and the NOx from diesel is less of an issue in colder northern climates like Germany than it is in warmer areas like LA. NOx and particulates are harder to treat, yes, but that's partly because the tech to do it hasn't been developed for as long as it has for gas engines.
Vigo: it takes more to produce it than you get out by burning it, yes (that's the second law of thermodynamics), but much of that energy is captured from sunlight by the plants that are used as the input via photosynthesis. It's pretty expensive to make it this way compared to the traditional one, though.
In reply to codrus :
People have been trying to clean up diesel the entire time of CARB and the Clean Air Act. The problem is that nobody has found a way to reduce NOx in a very lean environment that is super robust. Trucks have gotten around it because most of them operated at a totally different standard than cars and light trucks (which is actually 90% of all trucks out there). So basic reductions were good enough up until recently.
And for the EU, diesel has a totally different standard, as it was favored for a few reasons (which has turned out to backfire on the EU). So you saw a huge swing to diesels from the early 90's to just recently.
Right now, the biggest problem with diesel is that it requires a very expensive system that is hardly robust (the root of the Mercedes investigation that Jamie was bringing up).
Before the VW thing, I predicted that diesel was going to disappear in the EU due to cost except for the high end market. Now I think it's just going away. If you look at the air (not measure it, just LOOK at it), you can see the result of many years of diesel emissions. Pretty disgusting, if you ask me. The snot you would put out after running was kind of scary.
I too learned something about diesels today. I learned my Cummins' injection pump needs rebuilt. 
Its thr particulate that is specifically bad for humans. That stuff gets I your lungs and dosent come out.
Wait, diesel fuel isn't a perpetual energy machine? Well that totally contraverts what i was trying to say! 
The funny thing about being better for NOx, CO, CO2 is that those are the ones that actually disperse into the wider atmosphere. Not that they aren't a problem, but they're a bit of a red herring in terms of diesel emissions when the particulates are what you you're walking and rolling around on top of and making constant direct contact with and getting almost all your health risk from. If we wanted a term that brought attention to those dangers instead of sort of subliminally distracting from them like 'better CO!' et al, we can just say 'diesel fallout', since technically that's a correct description too.
While I agree with everything in the article, it really irks me that everyone has jumped onto the "we have a pollution problem, we need to totally re-engineer and rebuild our entire automotive industry" before taking a look at the cost/effect/effort. We would get much further, faster, by going after large ocean shipping and cruise ships before ever making the car the scapegoat of modern pollution. Simply putting some regulations and proper exhaust systems in place for those large ships and especially cruise ships would give us a larger decrease in harmful particulates than any change in cars ever would. It drives me nuts that we spend so much time arguing and policing the car when we could go after the 300 or so cruise ships in the US to get the same drop in emissions. My 2 cents idk.
In reply to LarsBrunkhorst :
Oh I agree regarding scapegoating the car. From the research I've done, it’s not the biggest culprit to pollution.
In reply to LarsBrunkhorst :
FWIW, the law requires that the cost/benefit equation is examined pretty sharply when new standards are thought of. And when you look (again you can see it) the air quality problems in areas that 90% of the pollution is cars, it's not really scapegoating- it's quite real. Heck, the clean up of air in my lifetime is pretty amazing- and I do remember how cars smelled in the 70's.
And at the same time recent restrictions happened for cars, they also have happened for ships. Which is a different animal, as that took a world wide treaty to do that effectively. But there are emissions controls on shipping and cruise ships.
Vigo said:Wait, diesel fuel isn't a perpetual energy machine? Well that totally contraverts what i was trying to say!
The funny thing about being better for NOx, CO, CO2 is that those are the ones that actually disperse into the wider atmosphere. Not that they aren't a problem, but they're a bit of a red herring in terms of diesel emissions when the particulates are what you you're walking and rolling around on top of and making constant direct contact with and getting almost all your health risk from. If we wanted a term that brought attention to those dangers instead of sort of subliminally distracting from them like 'better CO!' et al, we can just say 'diesel fallout', since technically that's a correct description too.
Particulates, interestingly enough, are a good chunk of why we've got glaciers disappearing. It settles on the ice, and makes the ice less reflective. Less reflective means it absorbs more heat.
CyberEric said:Oh I agree regarding scapegoating the car. From the research I've done, it’s not the biggest culprit to pollution.
Cars have been cleaned up to a massive degree, and environmental regulators are now chasing ever more diminishing returns with increased standards. IIRC there are days in LA where running a modern car actually improves the air quality -- what's coming out the tailpipe is cleaner than the ambient air.
In 1972, my chemistry professor went on a tirade about the sooty pollution from heavy trucks. I guess he was well ahead of the times.
codrus said:Cars have been cleaned up to a massive degree, and environmental regulators are now chasing ever more diminishing returns with increased standards. IIRC there are days in LA where running a modern car actually improves the air quality -- what's coming out the tailpipe is cleaner than the ambient air.
Very true, I remember reading that. The Porsche 911 Turbo, specifically, was measured at the tailpipe to have less of certain emissions than the outside air.
On the rail side, we've got Tier IV emissions on all the new diesels, urea injection, the whole shebang. It's been a difficult period. Reliability is still not there, compared to the old smoky 2 strokes that run and run and run and everybody knows how to fix when they don't. The modern stuff is not only more complex, but has shorter maintenance intervals. I've discussed at length with others wondering what the real benefit of the Tier IV stuff is when we have to do more frequent oil changes (at 200 gallons per engine per change) and replace things like injectors, pumps, etc much more often. I guess used motor oil doesn't make particulate matter. 
A friend of mine (who is not a train nerd) asked another friend of mine (who is a train nerd) why we don't have regenerative braking on locomotives. His reply was that we still haven't quite figured out how to turn electricity back into diesel fuel.
codrus said:CyberEric said:Oh I agree regarding scapegoating the car. From the research I've done, it’s not the biggest culprit to pollution.
Cars have been cleaned up to a massive degree, and environmental regulators are now chasing ever more diminishing returns with increased standards. IIRC there are days in LA where running a modern car actually improves the air quality -- what's coming out the tailpipe is cleaner than the ambient air.
This isn't a bad thing.
I like the concept of catalyst coatings on the radiators, myaelf.
volvoclearinghouse said:On the rail side, we've got Tier IV emissions on all the new diesels, urea injection, the whole shebang. It's been a difficult period. Reliability is still not there, compared to the old smoky 2 strokes that run and run and run and everybody knows how to fix when they don't. The modern stuff is not only more complex, but has shorter maintenance intervals. I've discussed at length with others wondering what the real benefit of the Tier IV stuff is when we have to do more frequent oil changes (at 200 gallons per engine per change) and replace things like injectors, pumps, etc much more often. I guess used motor oil doesn't make particulate matter.
A friend of mine (who is not a train nerd) asked another friend of mine (who is a train nerd) why we don't have regenerative braking on locomotives. His reply was that we still haven't quite figured out how to turn electricity back into diesel fuel.
If you only think about emissions from an environmental standpoint, I can understand why you'd have some questions or wonder what he real benefit is. The truth is that there's more to emissions than just their environmental impacts. Not everything out of a tailpipe has an equal impact or impacts the same thing. Some compounds have little impact on humans, but more on the environment (CO2), while others like NOx and PM have more severe impacts on human health.
So, the regulations are written and enacted to prioritize eliminating the things that harm humans over the things that harm the environment. This is also why they prioritize emissions of on-road vehicles over off-highway vehicles which are fewer in number and more likely to operate around fewer people. They've made great strides in reducing the human health risks (NOx/PM/Hydrocarbons), and now they'll turn to reducing the environmental impact next (CO2).
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