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I hate seeing this conversation about diesel when we should be having this discussion about gasoline. Gasoline engines have lesser thermal efficiency and lesse

I hate seeing this conversation about diesel when we should be having this discussion about gasoline. Gasoline engines have lesser thermal efficiency and lesser torque potential than diesel engines. If you're going to get rid of one or the other, get rid of gasoline vehicles. Diesel engines have a longer stroke, cooler combustion, more flexibility with air/fuel ratios, extreme wear tolerance, lower rotational speeds, and cost the same with similar complexity to gasoline engines. They are also more economical in practice because their extra low-end torque gives them (arguably) a drivability advantage which lends itself to increased MPG. They are superior to gasoline engines in every way. And because they can run with air/fuel ratios anywhere from 10:1 all the way to 60:1 they can easily run a mutitude of different fuel's with only minor software adjustments. So please, stop shitting on diesel. It's ignorant to the fact that you probably drive a gasoline powered car that does more damage to the environment per gallon of fuel burned than a diesel bus.

gamblor956 8y ago
They are superior in every way except the one that matters: diesels are much dirtier than gasoline engines, especially with respect to particulate emissions. Diesels are only good for limited purposes, like buses and trucks, that need the higher efficiency.
- haloux 8y ago
  That's a really difficult argument to make without a source. A lot of recent research is disproving the age-old trope of 'Damn Dirty Diesel'. sources and additional reading: https://pubs.acs.org/doi/pdf/10.1021/es034928d https://pubs.acs.org/doi/pdf/10.1021/es034928d https://phys.org/news/2017-05-carcinogenic-soot-particles-petrol.html https://phys.org/news/2017-05-carcinogenic-soot-particles-pe... https://www.energy.gov/sites/prod/files/2014/03/f9/2002_deer_ahlvik.pdf https://www.energy.gov/sites/prod/files/2014/03/f9/2002_deer...
  - jeffwass 8y ago
    First paper only covers CO2. Second paper only considers fine-size (<20 nm) particulates (and not larger sizes like 100nm+) of direct injection cars, and is a bit misleading by comparing six cars to a single carefully-selected diesel car with particulate filter. Further, in reality here in a London, people are cutting open their Diesel particulate filters to avoid cost of replacing clogged filters and still passing MOT exhaust tests, which apparently don’t/can’t check for filter tampering. Third paper is way back in 2002 and considers only cars, not heavy trucks and buses, which are way worse in urban settings.
    - gamblor956 8y ago
      As jeffwass notes, diesel is better at CO2 emissions. But in California, particulate emissions matter more, especially in SoCal, which is prone to inversions that trap particulate pollution.
    - djaychela 8y ago
      I don't disagree with your points here, other than the MOT changed in May to include inspection of the DPF system if fitted (on 2006 onwards vehicles) , including checking for one which has been cut open. Obviously not foolproof, but at least its a start - if the DPF is missing, it's a fail now.
tdr 8y ago
> They are superior to gasoline engines in every way. What about pollution? There is sufficient evidence that the fine particles cause cancer [0]https://www.cancer.org/cancer/cancer-causes/diesel-exhaust-and-cancer.html https://www.cancer.org/cancer/cancer-causes/diesel-exhaust-a...
- zelon88 8y ago
  See my previous reply.
jeffwass 8y ago
Please cut this diesel apologist Bullshit! Your defense of diesel entirely ignores exhaust and emissions. Sorry to be rude but this is a very personal and emotional topic to me and you’ve really pissed me off by saying “They are superior to gasoline engines in every way.” You apparently aren’t living in a city where the poor-sighted decision was made to promote Diesel engines over gasoline for marginally better CO2 metrics, and now get to breathe air that exceeds annual EU pollution limits in mere days. Diesel is terrible in urban settings. It’s dirty as hell. I have no idea where you live but Diesel engines are entirely on their own choking the streets of London with their particulates and NoX exhaust. Gasoline engines are much cleaner by comparison. I’ve gotten bronchitis several times in the past few years. I’ve finally tracked it down to the nox fumes, primarily from buses and heavy trucks where it’s a very noticeable sharp smell. I’ve gotten a bit better by avoiding high streets whenever possible, and I’m also proactively going up to drivers in idling diesel cars and asking them to cut the engine. It’s been estimated that 10k people are dying a year in London alone from effects of the exhaust!!
- usrusr 8y ago
  > I’ve gotten bronchitis several times in the past few years. I’ve finally tracked it down to the nox fumes Oh, I'd really love to hear how you did that.
  - jeffwass 8y ago
    Correlation of coughing fits with noticing an earlier exposure to walking through a NOx cloud. The NOx smell is unmistakable once you identify it. The tricky part is that there’s usually a delay of a few hours between exposure and cough attack. Intentionally avoiding high streets has helped for me. I still get coughing fits but not as many full on cases.
- zelon88 8y ago
  Diesel particulates (aka: soot) comes from unburned fuel during the combustion process due to insufficient heat in the combustion chamber. This can be reduced with software that eases into the throttle instead of literally translating the input from the gas pedal into throttle input. Applying the throttle slower results in more complete fuel burn. Here in the USA when you crank up your injectors to create the black cloud of smoke it's called "rolling coal." It's how you get more power out of a diesel engine without changing anything else. Just pour in more fuel. Because they don't have butterfly valves in the intake or throttle plates, diesel engines usually operate at or in excess of 100% volumetric efficiency. So while a 2.0L gas engine will consume 900cc of air at partial throttle, a diesel engine WILL ALMOST ALWAYS consume approximately it's displacement worth of air on an intake stroke. So a 2.0L diesel, even at part throttle, is consuming around 2.0L (or more) of air per intake stroke. So to limit particulates, add a throttle limiter that limits throttle changes to a certain speed where the temperature of combustion increases proportionate to the fuel being injected. You can also reduce soot output by filtering the fuel. You can refine diesel until you're blue in the face, but the fact of the matter is you get to a point where the cost of refining it isn't worth the benefit coming out of the tail pipe. Not to mention the soot falls back to Earth and doesn't stay in the atmosphere as long as you think it does. So much of that black cloud is getting washed into your sewers when it rains. You've found a bug in your code and you want to throw it all out and start over?
andygates 8y ago
> I hate seeing this conversation about diesel when we should be having this discussion about gasoline. We're really having this conversation about combustion. For city driving of all types, it's time is very nearly up.

gamblor956 8y ago

They are superior in every way except the one that matters: diesels are much dirtier than gasoline engines, especially with respect to particulate emissions. Diesels are only good for limited purposes, like buses and trucks, that need the higher efficiency.

haloux 8y ago
That's a really difficult argument to make without a source. A lot of recent research is disproving the age-old trope of 'Damn Dirty Diesel'. sources and additional reading: https://pubs.acs.org/doi/pdf/10.1021/es034928d https://pubs.acs.org/doi/pdf/10.1021/es034928d https://phys.org/news/2017-05-carcinogenic-soot-particles-petrol.html https://phys.org/news/2017-05-carcinogenic-soot-particles-pe... https://www.energy.gov/sites/prod/files/2014/03/f9/2002_deer_ahlvik.pdf https://www.energy.gov/sites/prod/files/2014/03/f9/2002_deer...
- jeffwass 8y ago
  First paper only covers CO2. Second paper only considers fine-size (<20 nm) particulates (and not larger sizes like 100nm+) of direct injection cars, and is a bit misleading by comparing six cars to a single carefully-selected diesel car with particulate filter. Further, in reality here in a London, people are cutting open their Diesel particulate filters to avoid cost of replacing clogged filters and still passing MOT exhaust tests, which apparently don’t/can’t check for filter tampering. Third paper is way back in 2002 and considers only cars, not heavy trucks and buses, which are way worse in urban settings.
  - gamblor956 8y ago
    As jeffwass notes, diesel is better at CO2 emissions. But in California, particulate emissions matter more, especially in SoCal, which is prone to inversions that trap particulate pollution.
  - djaychela 8y ago
    I don't disagree with your points here, other than the MOT changed in May to include inspection of the DPF system if fitted (on 2006 onwards vehicles) , including checking for one which has been cut open. Obviously not foolproof, but at least its a start - if the DPF is missing, it's a fail now.

tdr 8y ago

> They are superior to gasoline engines in every way. What about pollution? There is sufficient evidence that the fine particles cause cancer [0]https://www.cancer.org/cancer/cancer-causes/diesel-exhaust-and-cancer.html https://www.cancer.org/cancer/cancer-causes/diesel-exhaust-a...

zelon88 8y ago
See my previous reply.

jeffwass 8y ago

Please cut this diesel apologist Bullshit! Your defense of diesel entirely ignores exhaust and emissions. Sorry to be rude but this is a very personal and emotional topic to me and you’ve really pissed me off by saying “They are superior to gasoline engines in every way.” You apparently aren’t living in a city where the poor-sighted decision was made to promote Diesel engines over gasoline for marginally better CO2 metrics, and now get to breathe air that exceeds annual EU pollution limits in mere days. Diesel is terrible in urban settings. It’s dirty as hell. I have no idea where you live but Diesel engines are entirely on their own choking the streets of London with their particulates and NoX exhaust. Gasoline engines are much cleaner by comparison. I’ve gotten bronchitis several times in the past few years. I’ve finally tracked it down to the nox fumes, primarily from buses and heavy trucks where it’s a very noticeable sharp smell. I’ve gotten a bit better by avoiding high streets whenever possible, and I’m also proactively going up to drivers in idling diesel cars and asking them to cut the engine. It’s been estimated that 10k people are dying a year in London alone from effects of the exhaust!!

usrusr 8y ago
> I’ve gotten bronchitis several times in the past few years. I’ve finally tracked it down to the nox fumes Oh, I'd really love to hear how you did that.
- jeffwass 8y ago
  Correlation of coughing fits with noticing an earlier exposure to walking through a NOx cloud. The NOx smell is unmistakable once you identify it. The tricky part is that there’s usually a delay of a few hours between exposure and cough attack. Intentionally avoiding high streets has helped for me. I still get coughing fits but not as many full on cases.
zelon88 8y ago
Diesel particulates (aka: soot) comes from unburned fuel during the combustion process due to insufficient heat in the combustion chamber. This can be reduced with software that eases into the throttle instead of literally translating the input from the gas pedal into throttle input. Applying the throttle slower results in more complete fuel burn. Here in the USA when you crank up your injectors to create the black cloud of smoke it's called "rolling coal." It's how you get more power out of a diesel engine without changing anything else. Just pour in more fuel. Because they don't have butterfly valves in the intake or throttle plates, diesel engines usually operate at or in excess of 100% volumetric efficiency. So while a 2.0L gas engine will consume 900cc of air at partial throttle, a diesel engine WILL ALMOST ALWAYS consume approximately it's displacement worth of air on an intake stroke. So a 2.0L diesel, even at part throttle, is consuming around 2.0L (or more) of air per intake stroke. So to limit particulates, add a throttle limiter that limits throttle changes to a certain speed where the temperature of combustion increases proportionate to the fuel being injected. You can also reduce soot output by filtering the fuel. You can refine diesel until you're blue in the face, but the fact of the matter is you get to a point where the cost of refining it isn't worth the benefit coming out of the tail pipe. Not to mention the soot falls back to Earth and doesn't stay in the atmosphere as long as you think it does. So much of that black cloud is getting washed into your sewers when it rains. You've found a bug in your code and you want to throw it all out and start over?

andygates 8y ago

> I hate seeing this conversation about diesel when we should be having this discussion about gasoline. We're really having this conversation about combustion. For city driving of all types, it's time is very nearly up.