Megasquirt Support Forum (MSEXTRA)

Well I'm hoping someone more knowledgable than me will have a crack at the base code and use me as their lab rat!

Thanks for the tips on further reading - I guess its time to go hunting on Amazon and ebay.

well, milestone # 1 get common rail ro run with megasquirt one single injection per cycle.

the 5 injection per cycle ability should not be to much more difficult. either using the ms3 code or built in processor in the injector driver to divide up the injection cycle. that is more down the road. and frankly i don't realy care that would be just modifying code.


current milestones

injector driver circuit, we have a good idea of what we need for this.

voltage booster. the conversion from 12 volts (8 -16 volts ) to 100- 150 volts is the current concern. the ability to do this with out much cost.

the idea of the 100 watt automotive to domestic power inverter is still on the table.

Has anyone considered megasquirts ability to control the rail pressure? The fuel pressure control in most modern common rail systems control the fuel going through the high pressure pump (inlet metering valve) and the pressure in the rail via another valve at the end. You can probably get away with just the IMV however.

Just to add to the chat about number of injections per cycle, you'll notice a big change in combustion noise from pilot+main to main injection only (think black taxi vs. modern diesel).

I can probably dig out holding current and period for Delphi solenoid injectors if needed by anyone, but not sure about Continental or Bosch....

megasquirt should not have a problem controling rail pressure.

my understanding is there is a pwm valve supplying fuel to the highpressure pump. so megasquirt will simply control this valve using generic outputs.

don't care about combustion noise.. actually like it.

frank_ster wrote:megasquirt should not have a problem controling rail pressure.

my understanding is there is a pwm valve supplying fuel to the highpressure pump. so megasquirt will simply control this valve using generic outputs.

How will you increase rail pressure with demand for increasing load? that sounds like a software coding nightmare. You can't just hook it up to a PWM output and call it "easy."

Bosch did it...

bobtooke wrote:Bosch did it...

I'm not saying it can't be done - FYI. Bosch charges a minimum $500,000USD and requires a purchase commitment to get a hold of their Diesel PCM. I worked on one here in the states, the user guide was a stack of books 4 feet tall. Gale Banks bought the license and asked me to help get them up to speed.

All I am saying is, those in this thread who think the Injectors are the biggest challenge - are mistaken. It would take a firmware rewrite and probably a better way of identifying engine position - Bosch ran a dedicated Time Processing chip on the PCM I used. This isn't trivial stuff - the best way to figure out just how complex diesel engine management is, is to read any o the Bosch documentation on the subject.

dieselgeek wrote:

frank_ster wrote:megasquirt should not have a problem controling rail pressure.

my understanding is there is a pwm valve supplying fuel to the highpressure pump. so megasquirt will simply control this valve using generic outputs.

How will you increase rail pressure with demand for increasing load? that sounds like a software coding nightmare. You can't just hook it up to a PWM output and call it "easy."

with a ve table .. either rpm vs throttle or rpm vs map will dictate fuel pressure.

also bosch and the others need to deal with more than running a diesel engine. they have to deal with noise, fuel economy, error trapping, limp home self protectection. and a bizillion other things.

frank_ster wrote:

dieselgeek wrote:

frank_ster wrote:megasquirt should not have a problem controling rail pressure.

my understanding is there is a pwm valve supplying fuel to the highpressure pump. so megasquirt will simply control this valve using generic outputs.

How will you increase rail pressure with demand for increasing load? that sounds like a software coding nightmare. You can't just hook it up to a PWM output and call it "easy."

with a ve table .. either rpm vs throttle or rpm vs map will dictate fuel pressure.

So how do I set up my MS3X VE table currently to handle this? Can it read a 360, 720 or 3600 trigger wheel?

frank_ster wrote: also bosch and the others need to deal with more than running a diesel engine. they have to deal with noise, fuel economy, error trapping, limp home self protectection. and a bizillion other things.

You forgot closed loop fuel pressure management, there's a whole CPU in a Bosch unit dedicated to monitoring and maintaining fuel pressure. You don't want to do it open loop, how will that work? so far we have a nice stack of programming requests that we should send to Ken and James, I'm sure they won't mind doing all this for free. Hopefully you start seeing my point that doing this with current MS3X hardware is a pipe dream.

bobtooke wrote:Bosch did it...

Yes, but just because NASA made a space shuttle, doesn't mean that you and I can too !

James

jsmcortina wrote:

bobtooke wrote:Bosch did it...

Yes, but just because NASA made a space shuttle, doesn't mean that you and I can too !

James

Thats very true, if I built a space shuttle it would probably explode during the launch procedure... ohh hang on a mo

I can plainly see the complexity, all I'm saying is that it wasn't so long ago people thought all of efi was a dark art. With determination and some of the genius innovators we have on here I'm sure its feasible to replicate what Bosch achieved.

Modern turbodiesels are rapidly overtaking petrol cars in terms of performance and popularity, even in motorsport. I think more and more people will be looking for aftermarket TD ECU solutions so its worth investing the effort.

Truck and Tractor pullers here are already dropping $7000+ for "prototype" standalone diesel units so it would be well worth the effort, I think.

And the "standalone" they're using now isn't really even tuneable. I think there is a lot of pent-up demand for it. It just takes a new level of effort on the part of coders and hardware designers.

Telling us something can't be done on the current hardware has me (and James probably too) interested in figuring out what would be necessary at least.

Ken

I'm a diesel engineer and I know having worked at Delphi and for Bosch and Conti the rail pressure control is not simple. Definitely you want closed loop control on something that is working at up to 2000 bar. There is also the problem with correcting fuel flow rates for the range of pressures...then there is the pressure wave compensation...

This would all be done for each type of nozzle, even for the same engine... As people have said, you could probably do something reasonably 'quick and dirty' as you're not worried about NVH or emissions. Probably would need the maps to be based on N vs pedal as based on MAP is not so critical with an oil burner....

This is quite interesting isn't it? I'm going to have a chat with guys here at work and see what issues we can come with to add to this discussion...

they way things get done is tackeling one problem at a time. first we need injector driving ability, once this has been dealt with then we can work on multiple injections. and then rail pressure.

my boss has a 2011 jetta tdi , i will steal it and start unplugging things like fuel pressure control and others. see what it does.

frank_ster wrote:they way things get done is tackeling one problem at a time. first we need injector driving ability, once this has been dealt with then we can work on multiple injections. and then rail pressure.

my boss has a 2011 jetta tdi , i will steal it and start unplugging things like fuel pressure control and others. see what it does.

One thing to keep in mind before you do - When's your next pay review?

i have been trying to quit for 3 years...

muythaibxr wrote:Telling us something can't be done on the current hardware has me (and James probably too) interested in figuring out what would be necessary at least.

Ken

I guess I need to see if I can find the trigger wheel on that Duramax sitting around here and see what pattern it is...

Any more thoughts/progress?