Variables explanations

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Joined: Tue Dec 03, 2019 8:48 am

Variables explanations

Post by sverza » Tue Dec 03, 2019 8:55 am

thanks for your useful app.
If possibile, I would like to have some info about some variable monitored:
- differences between different post injections (1, 2, 3).
I've searched on the documentation you reported ( and the only place where I found something related is at page 60 where basically the 3 types are described during an active regeneration
If you have more tips, you are welcome!
- EGR management:I suppose the app is reporting the EGR described at page 51/52 "V339 EGR Motor 2.", am I correct?
Is there a way to monitor also the first one (page 50) High pressure?
In this point I'm quite confused... someone reports the engine has 1 egr (high or low, as reported in the pdf above mentioned), someone reports both are working in the same time... honestly I don't have any reference where I can find an answer.

UPDATE: I've noticed the app shows also DIFFERENTIAL PRESSURE when launched and not connected. As soon as it is connected to the ECU the field POST INJECTION 1 appears instead the DIFFERENTIAL PRESSURE. Which is the reason?

Just to let you know I have a CXXB engine, see attached

Again, many thanks

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Re: Variables explanations

Post by admin » Wed Dec 04, 2019 12:38 pm

Here the answers based on what I've learned in last years (I'm not an engine technician):
  • Post injections are used by engine ECU to reduce nocive emissions and engine noise, the difference between 1 2 and 3 is just the timing, number 2 is after number 1 and number 3 is after number 2, in normal use you'll see that the number 1 is the most used and the number 3 is rarely used; but the ECU uses these injections also to crete the conditions for the regeneration process, in fact this process is based on the temperature increasing that is obtained raising the fuel quantity of the post injections, post injections 1 and 2 increase the output gas temperature and post injection 3, that is deliberately retarded, permits to send unburned fuel into the DPF where it burns increasing even more its temperature. In this phase you'll see in the app these values considerably higher than standard, post injection 3 in particular.
  • EGR is explained well in pages 51-52 of the document you link, it participates in the regeneration process because it has direct impact in the engine chambers temperature and consequently in the output gas temperature. During the regeneration, the EGR valve is closed so it doesn't reduce the chamber temperature as usually it do. Depending on engine type, you can have low pressure EGR, high pressure EGR or both. Last engines, due to restrictive emission lows, have both EGR. In my app I add the value I found available in the ECU, but when I find both I add usually the low pressure value. I've also tried to add both value in the same field, but I reverted to a single value because the very low quality of the adapters in the market limits the reading of multiple blocks using the CANBUS protocol :(
  • Differential pressure is one of the last parameter I added, but unfortunately on all ECU have it available. If you don't find it, probably your ECU doesn't permit to read it.

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Joined: Tue Dec 03, 2019 8:48 am

Re: Variables explanations

Post by sverza » Wed Dec 04, 2019 2:17 pm

Thanks Sir, PM for you


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