OM648 Into Volvo c304 camping expedition vehicle

baldur

01-11-2019, 06:12 AM #14

(01-10-2019, 07:26 PM)Turbo thanks for the answer really looking forward to work with one... very interesting
My question regarding the pumps was for lowering pumping losses for great consumption but still plenty of power.

How hard is it to get more then 2 injections per cycle? is it a hardware or software limitation? simple can you use two units to get 4 event per cycle?

Regarding 2 injections per cycle is just beneficial for emissions, well bosch say for CRS2-25 system that use injectors like cri2-20/22/25 can use up to 8 individual injections for quieter combustion plus reduced fuel consumption and emissions (solenoid injectors)
http://www.bosch.co.jp/tms2015/en/produc...-25_EN.pdf
After a lot of looking I find and bought a bunch of CRI2-22 that will flow like 50% more then the BMW CRI3-22 injectors, and it would be nice to really see what is possible with them
perhaps you want to try some too

and the CRS3-27 system with CRI3-27(pizo) up to 10 event /cycle

There are a number of things that affect what can be done, but primarily it's the performance of the injector itself. Secondly it's the driver circuit and thirdly it's the control logic. My control logic currently needs about 100 microseconds between injection events for reliable operation. The driver circuit is boost assisted so it is capable of more frequent injections than the EDC15 which does not have a separate voltage booster circuit.
But you have to understand the purpose of each injection event to know how to calibrate the system. Pre injection is used to warm the charge air up just a little bit to speed up ignition of the main event (make combustion smoother, avoid diesel knocking). The main event then delivers all of the fuel that contributes to power. At low engine speeds the most modern systems may actually split the main injection into two or three closely spaced events to space out the delivery time without having to drop the pressure too far which hurts atomisation. Then you have optional post injection events that are just wasted fuel, do not contribute to making power in any way, shape or form. The first post injection event is to re-light the mixture to try to burn some of the soot that formed in the main combustion event. Second post injection event is then used to heat up the exhaust gas to warm up emissions control gear as well as regenerate DPF.
What makes common rail different from every other diesel control technique except hydraulic unit injectors which is the closest thing to CR, is that you have control of the injection pressure so you can control the injection duration independently of the injection quantity.
I suggest you send me a message if you want to discuss this further, as this is not the topic of this thread.

Baldur Gislason

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