Can be try to straighten out a few things here? There seems to me to be a few misconceptions mixed in with some accurate information.
Opinion, prejudice, half-truths and wishful thinking seem to get mixed in with facts. Just like a good pub discussion, or a Parliamentary debate.
Keeping just to our truck engines.
AdBlue is used in SCR (Selective Catalytic Reduction) engines to clean up the emissions. In Euro6 theyre getting the particulate and NOx levels down really low. This isnt affecting (greatly) the CO2 levels.
Let`s pull that apart.
First, lets say that in an "ideal" diesel the exhaust would produce only carbon dioxide (CO2) and water. Water is OK but CO2 is a "greenhouse gas". More CO2 means Global Warming or better described as Climate Change, or what may turn out to be more extreme weather events. Burning twice as much diesel means twice as much CO2. Reducing CO2 means smaller fuel bills, and we can agree thats good. But nothing is perfect and exhaust gases have many other components.
Secondly, Euro 6 have a particulate filter to clean up the soot. When it gets clogged it squirts diesel in to burn off the crap at high temperatures. Easy enough to understand.
Thirdly, the SCR, Adblue bit. NOx gases are bad for your health and the environment. By squirting AdBlue (ammonia and water) into the exhaust gases, downstream of the particle filter, the NOx gases are converted into nitrogen N2 and water.
Here`s two links originally put up by Norb.
youtube.com/watch?v=fc6-nJ2 … e=youtu.be
youtube.com/watch?v=8JGVCPs … e=youtu.be
Much clearer than I put it.
All the above is pretty uncontroversial Id say. Thats the way it works.
Whether or not its "worth it" is another issue. Keeping the air clean is probably costing us money. If we had no emissions regs we could have less complicated, easier to maintain engines, which were possibly more fuel efficient*. Well 17 of the G20 countries have agreed that it is worth it. The USA and Japan are pretty much Euro6 too. It is NOT only a EU scheme. Brexit probably wont make any change.
If some places charge three times as much as others for AdBlue its clearly not a tax issue. Clean engines are more complicated and expensive than dirty ones? Well, thats true. Thats a choice we as a society have made. If some operators want to try to make money by cheating the system, then just make sure the fines take any competitive advantage theyve gained. Most of us don`t want to see haulage rates cut by companies running bent on hours, why put up with companies running bent on emissions?
*Using AdBlue technology in a cleaner engine makes it more fuel efficient than a non-AdBlue clean engine. But a dirty engine could be even more efficient.
