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> Gasoline engines don't produce all the particulate pollution that diesel engines do With injection engines this simply isn't true any more. > made a big mis

> Gasoline engines don't produce all the particulate pollution that diesel engines do With injection engines this simply isn't true any more. > made a big mistake by adopting diesel The small injection turbo diesel engines offered much higher efficiency and thus much lower CO2 emissions (~half) compared to contemporary gasoline engines (they still do). Other parts of the emissions profile (e.g. NOx) have almost exclusively to do with how efficient the engine is run, e.g. gas engines that are close to efficiency to diesel engines will produce similar amounts of NOx. Broadly speaking, as more aspects of the combustion are externally, forcibly controlled, differences between diesel and gas engines become a lot less. (The average German car has a 1.6 liter three or four cylinder engine doing something like 4.5l/100km ~ 50 mpg; basically no one is driving big cars with six or eight cylinder engines).

bunderbunder 8y ago
Regardless of what's technically possible, the fact remains that US standards for particulate emissions and nitrous oxide are quite a bit stricter than European standards. So much so that, as we discovered recently, at least one major European automaker apparently felt the best way to get their diesel cars cleared to sell in the USA was by, in effect, lying.
- azernik 8y ago
  One of the revelations of the VW scandal is that, when they actually comply with emissions standards, diesel engines are not cost- or efficiency-competitive; one interpretation of the events is the result of a failed overinvestment in a technology that didn't pan out. https://www.politico.eu/article/europe-looks-to-electric-cars-after-diesels-dead-end/ https://www.politico.eu/article/europe-looks-to-electric-car...
  - jacobush 8y ago
    Kind of reminds of how air-breathing nuclear jets have great performance, but possess other drawbacks. https://upload.wikimedia.org/wikipedia/commons/3/39/Aircraft_Reactors_Arco_ID_2009.jpg https://upload.wikimedia.org/wikipedia/commons/3/39/Aircraft...
thekingofh 8y ago
In theory.
epx 8y ago
Direct injection could be a potential problem for gasoline, but not that much in practice.
- blattimwind 8y ago
  Well, if you look at a modern gasoline engine the exhaust processing is basically the same as for a diesel engine. Particle filter, NOx cat, AGR etc.
- Reason077 8y ago
  As of the Euro 6c emissions rules, gasoline engines are subject to the same particulate count limits as diesel engines. This has resulted in the addition of particulate filters to certain 2018 model petrol vehicles (BMW, VW) in Europe. This suggests that prior to Euro 6c, some petrol engines were getting away with higher particulate emissions than would have been allowed for diesels.
growlist 8y ago
Using my lungs as the yardstick, diesel exhaust is far far worse than petrol.
nwallin 8y ago
You're correct when you say that the difference isn't in diesel vs gasoline. But for better or for worse, US regulations (read: California Air Resource Board (CARB) regulations, not federal/EPA regulations) are much more stringent in terms of particulates and NOx, while EU laws focus more on CO2 emissions. California is primarily worried about smog in LA, while Europe is generally much more concerned with maintaining the North Atlantic Current. As you said, the high efficiency gasoline engines generate more NOx and particulates, but these engines cannot pass a CARB smog test. Most cars have separate US vs EU specs, (or simply aren't available in one market) and the EU specs always have better power and gas milage. For instance, the 1.0L engine in my 2014 Ford Fiesta is rated for 123hp, but the same 1.0L engine in the 2014 EU spec Ford Fiesta gets 140. (EPA vs EU gas milage ratings aren't directly comparable) This is a direct result of the fact that the US version runs at a lower temperature, which necessarily results in lower power and efficiency, but also results in less NOx. Incidentally, this is a large part of why the US response to the VW emissions scandal was so different than the EU response. The affected VW engines broke EU regulations by a little, but broke CARB regulations by a lot. It's like going 70mph in a 55mph zone vs a 35mph zone.
- foobar1962 8y ago
  >Incidentally, this is a large part of why the US response to the VW emissions scandal was so different than the EU response. The affected VW engines broke EU regulations by a little, but broke CARB regulations by a lot. We had some Dutch friends visiting when the scandal broke. Their BIG concern was the emissions tax they paid to register the car for the road -- whether they would need to pay back-fees, and an increase in tax for future registration.
azernik 8y ago
> e.g. gas engines that are close to efficiency to diesel engines will produce similar amounts of NOx. Your core theoretical claims may be true, but this specific example was not the fact revealed by the emissions scandal. VW had to cheat on NOx emissions numbers to get their diesel engines to match gasoline efficiency and performance.
- Reason077 8y ago
  They didn't have to cheat on NOx. They could have installed a selective catalytic reduction (SCR) system with an end-user refillable urea (AdBlue) tank. Just like all heavy diesel vehicles have had for years now. It would have added maybe $100 in cost to each vehicle. The SCR system is an after-treatment for exhaust gasses and does not significantly affect fuel economy or performance.
deleted 8y ago
[deleted]
stefan_ 8y ago
The biggest mistake in all of this isn't even diesel vs gasoline, it's that the majority of engine and technology advancements have gone into making cars even more ridiculously powerful and oversize. If a fully loaded van can clear a 10% incline alpine pass with a mere 60 kW engine, there is no justification whatsoever to have any more than half that power in a car driving in the city, or pretty much all over the place. Gasoline vs diesel feels a bit like fructose syrup vs table sugar, it's pretty clear in both the US and Europe that regulations have not kept up enough of a downward slope on emissions to prevent technological advancement from going into grotesque growths like the SUV instead of cleaning up the exhaust and reducing consumption further.
- mmirate 8y ago
  And when the drunk driver of a 10-seat family van plows into you at high speed, do you want your "compact car" to become a "compacted car" with you inside? Personally, I don't believe my life is quite worth the money I'd have saved by driving a small sedan instead of the larger vehicle I drive. (If it were, then I daresay my budget would be severely lopsided. Seriously; what kind of idiot would I have to be to spend more than 70% of my net income to car-related expenses?)
  - corv 8y ago
    A pickup or SUV isn’t needed to stay safe - especially not when all other cars are compact. This reasoning reminds me of the tragedy of the commons.
    - TeMPOraL 8y ago
      This is totally tragedy of the commons reasoning. There exist big cars on the road, so I need a bigger one to protect myself against them. I'm half-surprised that no one is selling civilian-use APCs at this point.
      - mmirate 8y ago
        Pfft. I couldn't weave, pass and lanechange through the usual shitty traffic if my vehicle was that unmaneuverable.

bunderbunder 8y ago

Regardless of what's technically possible, the fact remains that US standards for particulate emissions and nitrous oxide are quite a bit stricter than European standards. So much so that, as we discovered recently, at least one major European automaker apparently felt the best way to get their diesel cars cleared to sell in the USA was by, in effect, lying.

azernik 8y ago
One of the revelations of the VW scandal is that, when they actually comply with emissions standards, diesel engines are not cost- or efficiency-competitive; one interpretation of the events is the result of a failed overinvestment in a technology that didn't pan out. https://www.politico.eu/article/europe-looks-to-electric-cars-after-diesels-dead-end/ https://www.politico.eu/article/europe-looks-to-electric-car...
- jacobush 8y ago
  Kind of reminds of how air-breathing nuclear jets have great performance, but possess other drawbacks. https://upload.wikimedia.org/wikipedia/commons/3/39/Aircraft_Reactors_Arco_ID_2009.jpg https://upload.wikimedia.org/wikipedia/commons/3/39/Aircraft...

thekingofh 8y ago

In theory.

epx 8y ago

Direct injection could be a potential problem for gasoline, but not that much in practice.

blattimwind 8y ago
Well, if you look at a modern gasoline engine the exhaust processing is basically the same as for a diesel engine. Particle filter, NOx cat, AGR etc.
Reason077 8y ago
As of the Euro 6c emissions rules, gasoline engines are subject to the same particulate count limits as diesel engines. This has resulted in the addition of particulate filters to certain 2018 model petrol vehicles (BMW, VW) in Europe. This suggests that prior to Euro 6c, some petrol engines were getting away with higher particulate emissions than would have been allowed for diesels.

growlist 8y ago

Using my lungs as the yardstick, diesel exhaust is far far worse than petrol.

nwallin 8y ago

You're correct when you say that the difference isn't in diesel vs gasoline. But for better or for worse, US regulations (read: California Air Resource Board (CARB) regulations, not federal/EPA regulations) are much more stringent in terms of particulates and NOx, while EU laws focus more on CO2 emissions. California is primarily worried about smog in LA, while Europe is generally much more concerned with maintaining the North Atlantic Current. As you said, the high efficiency gasoline engines generate more NOx and particulates, but these engines cannot pass a CARB smog test. Most cars have separate US vs EU specs, (or simply aren't available in one market) and the EU specs always have better power and gas milage. For instance, the 1.0L engine in my 2014 Ford Fiesta is rated for 123hp, but the same 1.0L engine in the 2014 EU spec Ford Fiesta gets 140. (EPA vs EU gas milage ratings aren't directly comparable) This is a direct result of the fact that the US version runs at a lower temperature, which necessarily results in lower power and efficiency, but also results in less NOx. Incidentally, this is a large part of why the US response to the VW emissions scandal was so different than the EU response. The affected VW engines broke EU regulations by a little, but broke CARB regulations by a lot. It's like going 70mph in a 55mph zone vs a 35mph zone.

foobar1962 8y ago
>Incidentally, this is a large part of why the US response to the VW emissions scandal was so different than the EU response. The affected VW engines broke EU regulations by a little, but broke CARB regulations by a lot. We had some Dutch friends visiting when the scandal broke. Their BIG concern was the emissions tax they paid to register the car for the road -- whether they would need to pay back-fees, and an increase in tax for future registration.

azernik 8y ago

> e.g. gas engines that are close to efficiency to diesel engines will produce similar amounts of NOx. Your core theoretical claims may be true, but this specific example was not the fact revealed by the emissions scandal. VW had to cheat on NOx emissions numbers to get their diesel engines to match gasoline efficiency and performance.

Reason077 8y ago
They didn't have to cheat on NOx. They could have installed a selective catalytic reduction (SCR) system with an end-user refillable urea (AdBlue) tank. Just like all heavy diesel vehicles have had for years now. It would have added maybe $100 in cost to each vehicle. The SCR system is an after-treatment for exhaust gasses and does not significantly affect fuel economy or performance.

deleted 8y ago

[deleted]

stefan_ 8y ago

The biggest mistake in all of this isn't even diesel vs gasoline, it's that the majority of engine and technology advancements have gone into making cars even more ridiculously powerful and oversize. If a fully loaded van can clear a 10% incline alpine pass with a mere 60 kW engine, there is no justification whatsoever to have any more than half that power in a car driving in the city, or pretty much all over the place. Gasoline vs diesel feels a bit like fructose syrup vs table sugar, it's pretty clear in both the US and Europe that regulations have not kept up enough of a downward slope on emissions to prevent technological advancement from going into grotesque growths like the SUV instead of cleaning up the exhaust and reducing consumption further.

mmirate 8y ago
And when the drunk driver of a 10-seat family van plows into you at high speed, do you want your "compact car" to become a "compacted car" with you inside? Personally, I don't believe my life is quite worth the money I'd have saved by driving a small sedan instead of the larger vehicle I drive. (If it were, then I daresay my budget would be severely lopsided. Seriously; what kind of idiot would I have to be to spend more than 70% of my net income to car-related expenses?)
- corv 8y ago
  A pickup or SUV isn’t needed to stay safe - especially not when all other cars are compact. This reasoning reminds me of the tragedy of the commons.
  - TeMPOraL 8y ago
    This is totally tragedy of the commons reasoning. There exist big cars on the road, so I need a bigger one to protect myself against them. I'm half-surprised that no one is selling civilian-use APCs at this point.
    - mmirate 8y ago
      Pfft. I couldn't weave, pass and lanechange through the usual shitty traffic if my vehicle was that unmaneuverable.