[Cat-tech]

Where does the 4 main cycles idea come from? As far as I've seen every 2350 file I looked at has 2 pilot, 2 post, and one main injection cycle. And from studying the file and datalogging, it appears to mainly use those for warmup, regen, or in idle/low fueling regions............

(edited 02-14-2020 for better clarification).

typical of a few diff red engines.

Pilot1 = 1st cycle.
Pilot2 = 2nd cycle.
Main = 3rd cycle.
Post1 = 4th cycle

(post2 ) = used mainly for SCR-only (no DPF) systems as in-cylinder dosing to clean the SCR element when soot clogging is detected. Some engines also use this cycle as part of the DPF regen system as well.

There are some variation to how these cycles are sued this based on year/model and pre-'2010 and post 2010 models, and what type of aft-treatment systems are sued.

An O-scope can be used when making adjustments to see what the final results really are though.

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Breaking it down, there should only be 4 cycles for the actual combustion to happen, and thus what is titically seen on an o-scope.


here is a pic of the first cycle singled out. There are actually only 11 pulses (plus some sort of half-pulse?. perhaps injector trim offset added?), but the camera was not fast enough to catch it without a bunch of artifacts appearing. When looking at it live though, it is clear that there was only roughly 11 +- slight variances (within cycle#1) depending on situation.

Oh ok I see what you're saying...