There is one hell of a lot of mis-information here, its quite staggering. I see MMTM is in full force as ever. Amazes me how some people claim to be experts, without the first clue.
Its interesting that even some truck drivers donāt have a basic understanding of how an engine, even in basic principles work. A guy a page or so back was talking talking about putting 90% petrol in the tank instead of diesel because petrol is cheaper.
It seems bizarre to have to maybe explain the inherent differences between a diesel and petrol engine, but there you go. The only control you have over a compression ignition engine is at what point to inject the fuel, there is no control over ignition itself. Maybe thats what a certain poster meant, but he wasnāt exactly clear on the fact.
It may interest some people to know that EGR actually reduces combustion temperature. The exhaust gas recirculation increases the specific heat capacity of the combustion mix, thus lowering the combustion temperature. The eco benefits actually stem from this fact, in that nitrous oxide is produced more efficiently at higher temperatures, thus by reducing the heat, you reduce the production of NOx.
Before exhaust gas is put back into the combustion chamber it passes through a heat exhanger to reduce the temperature thus allowing a greater amount of recirculated gas to be forced in. Again exhaust gas has a higher specific heat capacity than air, so again it serves tor reduce combustion temperature. There are compromises though, EGR will reduce the amount of fuel burned in the power stroke, thus energy and therefore power is lost. EGR also produces more particulate matter in the exhaust, which means more stuff to clog up the other emission reducing systems.
To more onto SCR for a secondā¦
To those who donāt seem to know, it has nothing to do with the combustion process, it isnāt injecting āintoā the engine, it comes after the fact, the only connection it has to engine operation is a map that helps the system decide how much to use in relation to engine operation/performance.
I have always been dubious towards the benefits of adblue, it still has problems inherent in its design, operating conditions affect its efficiency a great deal, and there is always the problem of un-reacted ammonia being released into the atmosphere.
To those who seem to think its corrosive, reading up reveals that it is slightly alkaline with a PH of 9. So and i quote ā¦
so should not be kept in contact with aluminium, brass, mild steel. Stainless Steel and Plastic tanks and fittings are recommended. Prolonged skin contact may cause irritation.
To put that into perspective, you can buy drinking water that is between PH9 and PH10, and is considered beneficial for your health. So i would say manufacturers are airing on the side of caution with those comments.
Mike C saidā¦
but its manufacture, transportation, and storage use more emmisions than it saves (in the real world)
This is the crux of the matter, very much like tescoās transporting ālocalā produce 3000 miles before it gets to your plate.
On top of that what we do in the UK, and even the EU for that matter, is but a drop in the ocean. The main polluters of the world, China, India, the Americaās etc are the ones who need to make significant changes.
As many have pointed out lately, and a view im subscribing too, is that this planet was here before we were, and it will be here after we destroy ourselves, its arrogant to think whatever we do will have that much of an impact on things. We arenāt having as great an impact as the governments would like us to think, its simply a good opportunity for them to spin more money out of our guilt through green taxes. Enabling them to secure their gold standard pensions, and increase their pay by 60% as was talked about recently
Itās a shame we have to deal with all this emmisions related crap, it destroys the character of decent engines and overcomplicates matters, emissions and efficiency do not run hand in hand, the Euro emissions system is simply another stumbling block for haulage operators.