4 ms·

Evidence for this? They product more soot and smog, but less CO2. For certain driving characteristics they are MUCH better than gas. (E.g. heavy trucks that req

Evidence for this? They product more soot and smog, but less CO2. For certain driving characteristics they are MUCH better than gas. (E.g. heavy trucks that require larger amounts of torque)

Mizza 8y ago
There is detailed discussions about SOx/NOx further down this thread. News articles are easily found as well: https://www.theguardian.com/environment/2017/may/15/diesel-emissions-test-scandal-causes-38000-early-deaths-year-study https://www.theguardian.com/environment/2017/may/15/diesel-e... http://erj.ersjournals.com/content/17/4/733 http://erj.ersjournals.com/content/17/4/733 https://www.theguardian.com/uk/2013/jan/27/diesel-engine-fumes-worse-petrol https://www.theguardian.com/uk/2013/jan/27/diesel-engine-fum... etc etc Diesel is significantly worse for human health than gasoline.
iguy 8y ago
Googling for numbers, many sources quote these EU tests which everyone's cheating on. Out in the real world it sounds like switching Petrol -> Diesel saves maybe 20-30% CO2, and emits 10-20x the NOx. https://www.sciencedirect.com/science/article/pii/S0048969717333296 https://www.sciencedirect.com/science/article/pii/S004896971...
- namibj 8y ago
  You can fix NOx with AdBlue. You can't fix CO2.
  - iguy 8y ago
    The paper I linked "sampled ... 56% of all passenger cars sold in Europe in 2016". So they all have this stuff, right? Maybe next year's models will actually use it fully, and become clean. I'm not holding my breath though, it seems like a political problem. And if they do use it fully, in the real world, will they still be more CO2 efficient, and by how much? After all, the efficiency measure is the major incentive for all this cheating.
    - namibj 8y ago
      AdBlue is usually made from natural gas, so one has to figure the CO2 it takes into it. It should be able to use less diesel fuel, but I don't know if the reduction there is worth the increase in AdBlue use. The hotter the engine burns, which in this case should mean the higher the compression/inlet pressure is, the higher the efficiency, as well as the NOx levels generated. The impact of particle filters on engine efficiency is not know to me.
bsder 8y ago
There's also increasing evidence that the kind of particulates that the newer diesel engines emit are actually worse for humans that the older ones. The particles are smaller size and seem to cross the blood-brain barrier as well as penetrating further into the lungs. I would say that it just simply isn't clear which one is actually better right now, but there are some concerning signs around diesel engines right now.

Evidence for this? They product more soot and smog, but less CO2. For certain driving characteristics they are MUCH better than gas. (E.g. heavy trucks that require larger amounts of torque)

Mizza 8y ago

There is detailed discussions about SOx/NOx further down this thread. News articles are easily found as well: https://www.theguardian.com/environment/2017/may/15/diesel-emissions-test-scandal-causes-38000-early-deaths-year-study https://www.theguardian.com/environment/2017/may/15/diesel-e... http://erj.ersjournals.com/content/17/4/733 http://erj.ersjournals.com/content/17/4/733 https://www.theguardian.com/uk/2013/jan/27/diesel-engine-fumes-worse-petrol https://www.theguardian.com/uk/2013/jan/27/diesel-engine-fum... etc etc Diesel is significantly worse for human health than gasoline.

iguy 8y ago

Googling for numbers, many sources quote these EU tests which everyone's cheating on. Out in the real world it sounds like switching Petrol -> Diesel saves maybe 20-30% CO2, and emits 10-20x the NOx. https://www.sciencedirect.com/science/article/pii/S0048969717333296 https://www.sciencedirect.com/science/article/pii/S004896971...

namibj 8y ago
You can fix NOx with AdBlue. You can't fix CO2.
- iguy 8y ago
  The paper I linked "sampled ... 56% of all passenger cars sold in Europe in 2016". So they all have this stuff, right? Maybe next year's models will actually use it fully, and become clean. I'm not holding my breath though, it seems like a political problem. And if they do use it fully, in the real world, will they still be more CO2 efficient, and by how much? After all, the efficiency measure is the major incentive for all this cheating.
  - namibj 8y ago
    AdBlue is usually made from natural gas, so one has to figure the CO2 it takes into it. It should be able to use less diesel fuel, but I don't know if the reduction there is worth the increase in AdBlue use. The hotter the engine burns, which in this case should mean the higher the compression/inlet pressure is, the higher the efficiency, as well as the NOx levels generated. The impact of particle filters on engine efficiency is not know to me.

bsder 8y ago

There's also increasing evidence that the kind of particulates that the newer diesel engines emit are actually worse for humans that the older ones. The particles are smaller size and seem to cross the blood-brain barrier as well as penetrating further into the lungs. I would say that it just simply isn't clear which one is actually better right now, but there are some concerning signs around diesel engines right now.