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Author: Subject: Megasquirt......on a diesel ????
NigeEss

posted on 19/11/13 at 12:37 AM Reply With Quote
Megasquirt......on a diesel ????

Is it feasible ? Assuming a common rail application.

In my mind it will work, after all the principles are the same, injector timing and duration.

Discuss

[Edited on 19/11/13 by NigeEss]





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coyoteboy

posted on 19/11/13 at 01:42 AM Reply With Quote
AFAIK, unless MS3 has changed it, megasquirt has no injection timing control? This makes it impossible to achieve diesel control, ESPECIALLY on a commonrail where the injection timing is often 1 pilot injection followed by a second "full" injection.

Megasquirt does ignition timing and injects "whenever", or in sequential on the MS3 I think it has a "whenever, but approximately here for each cyl". I'd have to check the manual.
This is because, on a petrol engine, injection timing is not particularly important, especially not at high load levels.

[Edited on 19/11/13 by coyoteboy]






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baz-R

posted on 19/11/13 at 02:42 AM Reply With Quote
ms2 and 3 have injection timing control but this is aimed at petrol users and im not even sure it would work on GDI's yet but its possible that even gdi petrol and diesel comon rail is in some form of alpha or beta firmware.

best place to look and ask is on msextra.com

also if you have no luck with megasquirt i have seen diesel engine control ecu's out there in the market

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MakeEverything

posted on 19/11/13 at 06:08 AM Reply With Quote
IIRC, cant you select fuel type on megasquirt?





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luke2152

posted on 19/11/13 at 07:34 AM Reply With Quote
Megasquirt is not amywhere near fast enough for common rail diesel because fuel needs to be precisely injected at exact point btdc. On petrol sequential injection timing need only be done on the correct stroke and even then only at low/mid rpm. So in a word, no. thereorically you could use it on a rotary pump diesel to control the advance and fuel metering solanoids but all the calculations in tunerstudio are based on petrol and injectors so would need serious amounts of trial and error to even get it running.
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ashg

posted on 19/11/13 at 07:59 AM Reply With Quote
source code for ms3 is available, the processor has scope to do it, nothing is impossible.





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matt_gsxr

posted on 19/11/13 at 09:36 AM Reply With Quote
just google it and you will find lots of good stuff

[Edited on 19/11/13 by matt_gsxr]

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luke2152

posted on 19/11/13 at 11:22 AM Reply With Quote
quote:
Originally posted by ashg
source code for ms3 is available, the processor has scope to do it, nothing is impossible.


You could be right about the ms3 processor. When I asked similar question on forums couple of years ago the consensus seemed to be that the ms2 processor was too slow.

I think another big issue would be getting the seperate ms ignition and fuel outputs to control the timing and duration of the same injector.

Also I seem to remember common rail needing 5 injection events per cylinder per cycle (pre injection to reduce knock, then several normal injections and a post injection to reduce emmisions). Not to say it wouldn't run ok with just one or two events if you could live with a bit of knock.

Maybe megasquirt could be used piggybacked onto original system fool the ecu that it needs to deliver more fuel under certain circumstances?

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coozer

posted on 19/11/13 at 12:47 PM Reply With Quote
Thing with petrol injectors is they are quite slow. The time from valve open to closed is fast, much faster than injector opening time never mind the full cycle. So petrol injectors spend most of the time injecting against a closed valve and thats why theres no point trying to make MS do it quicker so wont be much use on a direct injection oil burner. Stick with the correct, supplied with the car, ECU.





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DW100

posted on 19/11/13 at 01:05 PM Reply With Quote
A few fundamental issues would need to be sorted.

1st, common rail diesel solenoid type injectors are fired using around 80volts

and 2nd desired fuel quantity is controlled as much by rail pressure as injector timing.


P.s I'm a mechanic and I do a lot of common rail diagnostic work and understand the systems very well.

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ashg

posted on 19/11/13 at 01:46 PM Reply With Quote
it should be able to cope. ms3 can do windowed knock detection now so its already shown that it is capable of doing the processing. as for 80v trigger thats easy to solve too. with regards to fuel rail pressure you can reassign the ignition control blocks to deal with that. its all possible its just a lot of work.





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DW100

posted on 19/11/13 at 01:52 PM Reply With Quote
Yes all do-able, but as the pioneer it'll be a huge learning curve.

It would definitely be easier to get the existing engine management system to run stand alone and chip it to whatever is required.

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ashg

posted on 19/11/13 at 03:49 PM Reply With Quote
quote:
Originally posted by DW100
Yes all do-able, but as the pioneer it'll be a huge learning curve.

It would definitely be easier to get the existing engine management system to run stand alone and chip it to whatever is required.


oh yes most certainly.





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Simon

posted on 19/11/13 at 06:19 PM Reply With Quote
There is an aftermarket diesel ecu out there, but iirc, it's about £2500

I'm sure if they made it £700, they'd sell loads !

ATB

Simon

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coyoteboy

posted on 19/11/13 at 09:26 PM Reply With Quote
quote:

source code for ms3 is available, the processor has scope to do it, nothing is impossible.




Aye but last time I checked you need a £k compiler and linker to compile changes as the"free" version is limited to compilations smaller than the code requires.

You may also wish to check out the code license - IIRC the MS3 code is not licensed for use on non-MS mainboards which would hamper you.

[Edited on 19/11/13 by coyoteboy]






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