Full Sequential injection Knowhow/Prerequisites

[Matus]

Hi,

I would like to really understand operation of sequential injection. How it is working .. how settings in VEMS altering .. relation between Timing (Crank vs CAM) when I am trying more overlap settings, changing cams  etc.
I wasn't able to found any relevant documents about that .. if anybody knows or have something to read, please let me know.

[Leonhard]

This thread is helpful explaining injection timing:

http://www.motec.com/forum/viewtopic.php?f=39&t=769

For my understanding of VEMS injection strategy I created this drawing:

http://img4web.com/view/JNNJC

I made some good experience tuning Injection on closed valve and matching injection end angle for richest lambda.

regards

[Matus]

Hi, Thanks for input.

The case from drawing where injection pulse is starting when intake valve is closed .. during explosion. But what I wrote the main goal of Sequential injection is to inject fuel when valve is opened .. actually when air flow start to move in to cylinder.

It is still possible that I just didn't get it correctly

[Kamuto]

yes that's possible but it's not the correct way

[Matus]

OK so you know than how it is really.

I was facing with issue where my car have grinded cams changed timing overlap and also overal, modified heads bigger compression etc.
But we wasn't able really tune it anyhow as there was no reaction to change of timing  .... Torque curve was still the same no matter if I delay cams to crank or advance ... also when I play with overlap.   You know .. it is simply not possible to have this result so I bought VEMS that gives me also other valuable options and features however we have other car were we would like also tune timing ... but it have the same graph ...

So that stock ECU must be running in some mode lets say "not usual"    I would like to understand this topic as I would like to fix this car and also avoid to migrate this mistake to my engine with VEMS.

[Leonhard]

I think Injection end angle isn't your problem right now, running WOT (higher revs) injection duration ends up on open valve anyway.
What's makes this engine setup so special?

[Matus]

Honestly I don't think that there is anything special on that engine.

It is BMW 62B44  V8  ECU  BOSCH DME 5.1 ... it is Bosch fully sequential injection. 

But reason why I open this topic here is more knowledge demand. You know ... lest talk about VEMS Sequential injection. I will use secondary trigger ( CAM-SYNC)

There is "reference trigger tooth table"   How this is altering to setup  ?   When I put there numbers what that numbers should represent ?
How these numbers will be changed by change of timing ?  What it would be showing ?

Note .. : I replace that DME5.1 with VEMS for my engine .. but I am planning to use STOCK sensors  (Hall cam sensor) So at least I must understand what I am "sensing" and how to use it properly

[Leonhard]

All this information you find at VEMS Wiki, VEMSTune help topics and searching this forum.

M62B44 is done before, have a look here:

http://www.vems.hu/wiki/index.php?page=MembersPage

VEMS is learning by doing 

[Matus]

Yea I know.  This one is my own  however first M62.

http://www.vems.hu/wiki/index.php?page=MembersPage%2FBmwNoVanosVEight

So lets go back to main question... do anybody knows (for sure I suppose at least guy who did code for that) how it works and what relations are there ?

[jrussell]

Torque curve was still the same no matter if I delay cams to crank or advance ... also when I play with overlap.   You know .. it is simply not possible to have this result so I bought VEMS that gives me also other valuable options and features however we have other car were we would like also tune timing ... but it have the same graph ...

So you're not seeing any change in torque when changing the cam timing, but you think it's an injector timing problem? I'm a little confused. At higher RPMs anyway, the injectors are likely open most of the time, so the injector timing isn't as critical.

I think Leonhard's 0-720deg timeline is a great depiction of what is happening.

I don't really understand the original question, but from what I understand, the Injector Angle Curve config panel allows you to set the injector END angle with relation to crankshaft degrees. (of course since it wouldn't be to 720 if it was camshaft degrees). In general, you want the injector to spray on a closed intake valve so it atomizes from the valve heat.

Is that on the right track for your question at all?

[Matus]

OEM:
I agree with you.  Actually  I suppose that when it didn't react  it was just result of some error detection and protection of that stock ECU. We will try to figure it out and when I will have relevant result I will share it.

VEMS:

I have think that I am starting to inject sooner but the goal is to spray in to air flow not to port. At least that is what I understood from shared MOTEC knowledge share posted here by Leonhard. So I suppose that I must stat open injector in advance to cover delay.


Major question  : VEMS sequential injection understanding and correct setup.

 I have seen secondary trigger reference in numbers of crank.. what it means really ?   It looks like END of injection mark regarding graph shared by Leo

[Leonhard]

For fully sequential setup secondary trigger signal has to be placed before primary trigger signal (gap of 60-2 trigger wheel) to match ignition TDC of cylinder 1.
This is the main synchronizing part. According to firing order of your engine you fill out: h[2] table - ignition outputs and the injector group table.
Check on your engine the original timing of secondary trigger Hall signal, perhaps you have to rotate firing order to match the "right" first cylinder.
Here is a example for V8 trigger settings with 60-2 wheel:

http://img4web.com/view/V7EHNM

I would start with the default injection end angle (setting all to 720) until the engine is running and than make your own experience changing it.

regards

[MWfire]

if you want spray when intake valve is open, then you need to put in table around 180-200deg. That you need to tune on dyno.

[gunni]

Ultimately when you WANT to inject is of no concern, when you NEED to inject is another matter however.

You need to tune to what the engine needs

[Sprocket]

This may be a useful read?.......

http://papers.sae.org/2000-01-2834/