Fossil fuel efficiency vs emissions

[ExalyThor]

Hi! I just wanted to talk about something that grinds my ears and that is emission standards. My b5 passat gets an impressive 4.3l/100km combined, but it's only rated at euro2 emissions. Now why my neighbour with a new car burn 2 times as much fuel and still be fine, because it's an euro6. Even if it polutes less per l of burnt diesel, it burns twice as much. And let's say the dpf makes up for the aditional burnt fuel in terms of emissions, burning twice as much fuel means that car exhausts the limited amout of oil in the earth twice as fast, and trucks need to deliver the fuel twice as often. What do you think?

[tankyx]

It is just down to the age of the car.

 

Apparently my 2004 BMW 316ti (6.0L/100km on highway) pollutes more than a 2019 Porsche Cayenne Turbo S 

[dalekphalm]

2 hours ago, TheSponyX said:

Hi! I just wanted to talk about something that grinds my ears and that is emission standards. My b5 passat gets an impressive 4.3l/100km combined, but it's only rated at euro2 emissions. Now why my neighbour with a new car burn 2 times as much fuel and still be fine, because it's an euro6. Even if it polutes less per l of burnt diesel, it burns twice as much. And let's say the dpf makes up for the aditional burnt fuel in terms of emissions, burning twice as much fuel means that car exhausts the limited amout of oil in the earth twice as fast, and trucks need to deliver the fuel twice as often. What do you think?

As far as I can tell from looking up the Euro emissions standards, it's rated in g/km - which makes sense to me. If the newer car uses more fuel, it must still produce less grams per kilometer of emissions (there's a shit ton measured, and it's different between Diesel vs 'Petrol' (gasoline).

https://en.wikipedia.org/wiki/European_emission_standards#Emission_standards_for_passenger_cars

 

So while your car might burn less gas, it still emits more pollution than his.

[zassou]

i would assume your passat is a diesel? if thats the case you need to know that earler euro x standard, doesnt include NOX, ozone and other bad stuff.

 

diesel engines burns way hotter than petrol ones, first they are compress-ignited, up to 20:1 for passenger cars. where a typical petrol engine is somewhere between 9 to 13, depending on performance. diesel is injected into the combustion chamber when the piston reaches the top dead centre (tdc) where the air is hottest, and the fuel is spontaneous ignited. modern diesel cars are turbocharged, forcing more air into the engine and thus make it even hotter. where as petrol is introduced before they are compressed, the fin spray of fuel air mixture can cool the engine down.

 

in theory hydrocarbon fuel like diesel and petrol will turn into water vapour and co2 if it's burnt in a perfect scenario, but it's never the case in car engines. when fuel is burn in a especially hot engine, there are chance that nitrogen, which is 79% of the air, will combine with the oxygen to form various of nitrogen oxides (NOx) compound, which combines with water forms nitrous acid which causes a bunch of problems.

 

while diesel engines do have higher thermal efficiency than petrol, they do create a lot more pollutant, thats why they need egs and urea can. petrol engine by design runs cooler and less stressful then diesel, and they have a higher rev range that can cope with wider work load. modern petrol engine can be more efficient than diesel when combined with direct injection and port injection, together with akinson cycle and higher  compress ratio. some latest tech includes variable compress ratio from nissan that can contineously change the compress ratio fron 9 to 15:1.

 

in the past europe envioronment brasses was controlled by big autos, like vw, bmw and daimler. they made policies that favours co2 emission, party due to at the time most ppl think co2 is the only bad actor in the exhaust, and partly big auto wants to keep the japanese out because they can't produce reliable car at reasonable price. but as time goes, diesel car will be phase out, ever since vw scandal, people starting to realise diesel wasnt as clean as they were told.

[zassou]

european emission standards are fundermentally flawed, they focus heavily on carbon emissions where nox ozone are more dangerous than a lukewarm greenhouse gas. because co2 is a simple problem to solve, you just plant more trees. you can't just do something later to fix the nox and ozone, one is known to cause acid rain and lung desease, the other one is major air pollutant that should not formed on the low atmosphere.

 

that's why in recent years a lot of small turbo petrol engine cars, because they can give you low emission and high power, in theory of course. if the turbo doesnt spools up, its just a small engine, so by nature they burn less fuel. but when you need the power, the engine is squeezing hard to make the turbo spin to pump more air, sometimes more fuel to make extra power. and that is why they are not efficient. you dont have the toque you need in low rev, so you rev higher, spooling up the turbo and then your efficiency goes away.

 

a typical engine runs at maximum efficiency at medium-high load. too low it starves oxygen and producing soot due to incomplete combustion, too high it runs too hot and forms nasty pollutant. and that's why a higher displacement, naturally asperated engine can sometimes burn less fuel than lower one, because they are less stressed, you have higher torque at low end, and have higher rpm at the top without burning too hot.

 

often than not these small engines are over stressed in real life scenario, they cant produce as much torque as bigger engines, they can't even spin as fast as naturally asperated ones because they have a turbo to drag around. so in a system where tax is pretty much based on how big your displacement volume instead of the actual efficiency and pollution control, comsumers got fxxked.

[Mira Yurizaki]

I don't think it's the age of the car per se, but the design of the power system in its entirety. When California first introduced emissions standards, a lot of cars of the time didn't bother updating their power systems and engines that were expecting its exhaust free flowing to the muffler suddenly get screwed when a catalytic converter gets in the way. And while I'm sure having no catalytic converter is better for fuel economy no matter how you slice it, you can still work with the physics and make a design that works to mitigate the issues of "obstructions" in the exhaust flow overall.

 

To that end, while using less fuel overall may be better for long term energy endurance, the affects of emissions happens in the short term with regards to health and longer term if those health problems affect the ecology. Plus emissions can have wide reaching effects on other areas.

[bimmerman]

Aftertreatment technology and combustion management have come a huge way in a relatively short time, especially for diesels. It is absolutely plausible that a newer car pollutes less on a g/km or g/mi basis regardless of its fuel consumption rate.

 

 

 

 

[RonnieOP]

Im american so i dont know anything about euro emissions. But does the rating matter?

 

Do you pay more in taxes depending on the rating?

 

[ExalyThor]

5 hours ago, RonnieOP said:

Im american so i dont know anything about euro emissions. But does the rating matter?

 

Do you pay more in taxes depending on the rating?

 

No extra taxes but low standars are starting to not be allowed in big cities already.

[ExalyThor]

How many people who had respiratory problems or died because of the poor quality of air were also smoking? This kind of graph should me made. I bet 95% of the affected people were also smokers.

[RonnieOP]

1 hour ago, TheSponyX said:

No extra taxes but low standars are starting to not be allowed in big cities already.

Wouldnt cars already bought be grandfathered in?

 

Would be really dumb if they just banned older cars from being drove.

[TomvanWijnen]

16 minutes ago, RonnieOP said:

Would be really dumb if they just banned older cars from being drove.

lol that is sadly indeed what is happening in a lot of places...

[RonnieOP]

40 minutes ago, TomvanWijnen said:

lol that is sadly indeed what is happening in a lot of places...

I dont know much about EU but thankfully in the US that shit wouldnt fly.

 

Thankfully starting on Dec 1st in my state any car made in 2000 or before wont even have to go through emissions tests anymore.

[Monkey Dust]

10 hours ago, TheSponyX said:

How many people who had respiratory problems or died because of the poor quality of air were also smoking? This kind of graph should me made. I bet 95% of the affected people were also smokers.

I believe smokers would get recorded as smoking related deaths, as if you're a smoker that is what has done the most damage. It will mostly likely be asthmatics, people with heart conditions and the elderly.

 

Though indoor pollution is often worse than outdoor as many modern houses, and retro insulated older ones, are so air tight, so how much can be blamed on cars is open to debate... Cars certainly play a part, though some people seem to think that if we got rid of cars our city air would be as pure and clean as the Scottish highlands, and that is clearly bollocks.

[dalekphalm]

7 hours ago, Monkey Dust said:

I believe smokers would get recorded as smoking related deaths, as if you're a smoker that is what has done the most damage. It will mostly likely be asthmatics, people with heart conditions and the elderly.

 

Though indoor pollution is often worse than outdoor as many modern houses, and retro insulated older ones, are so air tight, so how much can be blamed on cars is open to debate... Cars certainly play a part, though some people seem to think that if we got rid of cars our city air would be as pure and clean as the Scottish highlands, and that is clearly bollocks.

That might be true - but there would be a massive air quality increase. Sure, it won't make a city like the Scottish highlands, but it will be better none the less.

[kokakolia]

On 11/24/2019 at 10:19 AM, Monkey Dust said:

I believe smokers would get recorded as smoking related deaths, as if you're a smoker that is what has done the most damage. It will mostly likely be asthmatics, people with heart conditions and the elderly.

 

Though indoor pollution is often worse than outdoor as many modern houses, and retro insulated older ones, are so air tight, so how much can be blamed on cars is open to debate... Cars certainly play a part, though some people seem to think that if we got rid of cars our city air would be as pure and clean as the Scottish highlands, and that is clearly bollocks.

Getting rid of cars would increase the quality of life ten fold! Air pollution aside, noise pollution and lack of space for... errr... people is a massive deal. In cities like the Hague with lots of pedestrian streets downtown, it's an absolute joy to walk around. You have all the space and it's so peaceful. You have a lot of tiny shops, cafes and restaurants too. Because people who walk around are more likely to stop and check things out. So getting rid of cars is great for business too. 

 

tl;dr CURSE CARS!!!!

[Donut417]

4 hours ago, kokakolia said:

Getting rid of cars would increase the quality of life ten fold! Air pollution aside, noise pollution and lack of space for... errr... people is a massive deal. In cities like the Hague with lots of pedestrian streets downtown, it's an absolute joy to walk around. You have all the space and it's so peaceful. You have a lot of tiny shops, cafes and restaurants too. Because people who walk around are more likely to stop and check things out. So getting rid of cars is great for business too. 

 

tl;dr CURSE CARS!!!!

Well in places like NYC not having a car or a not as big of a deal. But where I live you have to go 10 miles to buy groceries. We don’t have shit around where I live. The only major thing we have is the airport. Even in Detroit public transportation is so so from what I have read. Would be cool if we had some light rail that connected at least larger cities. 

[WihGlah]

It's worse than you think. New cars have new tech added every time the emissions standards are made tighter, making the cars more expensive, just so the car can achieve lower emissions on a specific predetermined drive cycle (that no-one actually drives like).

 

No-one actually gets the emissions that their cars are specified for.

[dalekphalm]

9 minutes ago, WihGlah said:

It's worse than you think. New cars have new tech added every time the emissions standards are made tighter, making the ars more expensive, just so the car can achieve lower emissions on a specific predetermined drive cycle (that no-one actually drives like).

 

No-one actually gets the emissions that their cars are specified for.

While the gist of what you said might be true - even if no one gets the emissions that the car is rated for, a newer car will still produce (in most cases) less emissions than an older car.

 

Especially since the older car likely never got it's rated emissions either.

[WihGlah]

50 minutes ago, dalekphalm said:

While the gist of what you said might be true - even if no one gets the emissions that the car is rated for, a newer car will still produce (in most cases) less emissions than an older car.

 

Especially since the older car likely never got it's rated emissions either.

Tell that to VW.

 

[dalekphalm]

30 minutes ago, WihGlah said:

Tell that to VW.

I assume you're referring to the emissions scandal?

 

I'm not sure how that applies here. Even the "clean diesels" that ended up being far more environmentally unfriendly than advertised are largely still better than older vehicles - aside from Diesels that specifically had a Urea filter - and that's just basic physics. Any diesel without a Urea filter will pollute more NOx than one with.

 

But aside from that one instance, what I said is largely true. A car from 2019 will typically pollute significantly less than it's equivalent from 1999.

[WihGlah]

13 minutes ago, dalekphalm said:

I assume you're referring to the emissions scandal?

 

I'm not sure how that applies here. Even the "clean diesels" that ended up being far more environmentally unfriendly than advertised are largely still better than older vehicles - aside from Diesels that specifically had a Urea filter - and that's just basic physics. Any diesel without a Urea filter will pollute more NOx than one with.

 

But aside from that one instance, what I said is largely true. A car from 2019 will typically pollute significantly less than it's equivalent from 1999.

You are clearly an expert. Please enlighten us as to your extensive qualifications.

[dalekphalm]

1 minute ago, WihGlah said:

You are clearly an expert. Please enlighten us as to your extensive qualifications.

What do my qualifications have to do with anything? This is the internet, so me telling you I'm a specialist in y would be pointless anyway, since there's no way for you to verify my claim to be an expert.

 

Not that I made any such claims.

 

So, do you have any counter points, or are we just gonna jump straight to "appealing an authority" strawman?

 

I would love to continue the discussion, instead of you making pointless comments about my supposed expertise though.

[WihGlah]

I don't disagree on any particular point. 

 

I just find it interesting that you needed to comment so vigorously.

 

[dalekphalm]

8 minutes ago, WihGlah said:

I don't disagree on any particular point. 

 

I just find it interesting that you needed to comment so vigorously.

 

We're discussing a topic, and I added to the discussion. If that is a problem, please take it up with a mod? I really don't know what else to tell you, lol.