Dang, you beat me to it, although they do bolt up like the old mechanical styles, much easier to swap out than the old oness ǝoɾ said:High pressure common rail. ~27,000psi+, no individual injection lines, hence the "common rail" just like gasoline fuel injection vehicles have. For the first time (for cummins ISB) injectors are not simply poppet valves that open anytime pressure is over xpsi. Now they have piezo electric connections and open like fuel injected cars. Each individual injector cost between $300-$1300 (x6)
Haven't seen inside of one yet, although I'm willing to bet it is much less complex than anything else seen on a B series ever before.
The benefits are tremendous. NVH, drivability and engine life. Common rail engines can get much more power per liter, are more efficient, and start better under all conditions. They have the ability to adapt to changes in altitude, temperature, and load, instantly and more accurately without the operator even knowing that it's going on. On some common rail engines, the operator can select how much power he wants or set the max GPH his machine will burn, all on the fly.ToxicDoc said:The distribution theory is the same, but the application is a little different. High pressure feedback, the routing of dumped fuel, etc is much more involved in this engine than with a gasoline rail injector with a simple regulator.
Of course all this stuff is required when you have diesel at 25,000+ psi, but I wonder excluding lowering the emissions are you getting any benefit from the complexity?
I didn't even think about that. It's kind of hard to light off a converter without HC to burn.s ǝoɾ said:Normal cats do not work well in diesels. They depend on rich-lean cycling that happens in gasoline engines. The in effect, DEPEND on HC to balance out the mix. Obviously w/o HC they do not work so well. Nothing to scavenge up the excess oxygen.
It's funny, the inherent tendency of gasoline engines to misfire (where HC comes from) is actually much like a dpf regen cycle, but it is using much less fuel, much more often.magnumRC said:I didn't even think about that. It's kind of hard to light off a converter without HC to burn.
So what you're telling me is that all this emissions stuff isn't an exact science and hundreds of millions of dollars are being spent on "guesses" that may or may not lead to another problem? Great...s ǝoɾ said:It's funny, the inherent tendency of gasoline engines to misfire (where HC comes from) is actually much like a dpf regen cycle, but it is using much less fuel, much more often.
A diesel engine dumps fuel maybe every 20 minutes (I am totally making that number up, I don't know how often regen happens) that is the HC required to react with the NOX. In the mean while it stores NOx in a "trap" waiting for those hydrocarbons. The part I am not sure about, but believe may be correct, is this is done through retarded injection timing? That would be the easiest way.
Gasoline engines kind of do the same thing, except they have several "regen" cycles where HC is dumped into the exhaust. We call those misfires. Of course the normal rich/lean cycling even without misfire, still produces carbon monoxide which will help strip that oxyen molecule(s) off the NOx and let it escape as co2 and pure nitrogen.
It's funny, the various ammonia or urea schemes, actually inject more nitrogen into the exhaust BUT the hydrogen attached, can scavenge up the oxygen from NOx, resulting in water and nitrogen.
That stuff is all theoretical. We end up with so many of these "unexplained" emissions, because the various reactions do not occur under ideal conditions (ratios, pressures, temperatures, ect ect) along with unpredicted additions such as engine oil additives getting thrown into the mix.
Obviously in the ideal world, or on paper you only end up with pure water and pure co2 (along with extra atmospheric air). In the real world, even those 2 can mix together to form weird secondary byproducts like carbonic acid.
Soon I might be able to tell more about it hopefully...
100% correct. I have been stating this for quite some time as well. Less vehicles with slightly more pollution per vehicle, ends up better than more vehicles with slightly less pollution per vehicle, or that is my guess anyways. I would hate for any gov't funds, mandates, or regulations be involved, and much more prefer this to be left a conscious decision left to the individual.magnumRC said:The best solution would be (cringe) public transportation. As public transportation exists now, it is one of the dumbest and stupidest things around. It's a huge waste of money.
The internal combustion engine isn't even an "exact science". We (the world) do not even know exactly how it works yet. Before anyone claims to know exactly how it works, I'll just say it. They are wrong. There are so many uncertainties, flukes, and things that cannot be predicted through computer modeling, since computer models can only be based off of info we already know.Hard_runner67 said:So what you're telling me is that all this emissions stuff isn't an exact science and hundreds of millions of dollars are being spent on "guesses" that may or may not lead to another problem? Great...
That's some deep philosophy, but ever so true.We don't even know how these engines work. There is no way you could...