Urea Injection releases the beast.
I am currently spec-ing out a new Peterbilt 389 for my business. Rushed to beat the new 2011 EPA standards, I was all set to pull the trigger on a 140K truck until I decided to research the new SCR urea injection technology that everyone seems to be afraid of..
The Cummins 550 ISX I have ordered is rumored to increase in price by 10K with the new SCR system, and everybody in the sales business is trashing the new engine because of it's cost, and the urea maintenance involved, hence my scramble to buy a current EGR 550. Last night, I thought I would take a look at what it's all about.
After Googling and reading about the new technology, I think I'm going to wait and buy one of these new engines.
What is happening is this:
In a nutshell, the urea that is injected into the exhaust is incredibly effective in breaking down ALL NOx gasses, and this allows the engine to run on much less power robbing, coolant system taxing EGR.
As we know, EGR substitutes exhaust gasses for oxygen in the combustion chamber. This lowers the available O2 to burn, hence lowering combustion chamber temperatures and lowering power, along with the lowered number of NOx released.
Want to know why your 6.4L is a dog stock? The engine isn't allowed the benefit of oxygen to burn in order to make emissions. It's basically chocked to death. With SCR, we can now turn down the EGR which turns UP the oxygen. This makes for a stronger powerband, more crispness and definitely more power and fuel economy while lowering operating temps. There is basically NO ECM induced regeneration because the extra DPF clogging soot from the EGR isn't produced, and regeneration can be achieved passively. instead of by active means.
Ford is taking credit for reinventing the wheel with the 6.7L, but I submit that the better power and fuel efficency comes directly on achieving emission standards with less EGR that the SCR injection now allows..
The new technology, with all of the inconveniences of filling the urea tank will bring back the old snappy diesels, and I for one am buying in.