MoTeC Global Forum

Hi,
Ive noticed an possible error within the M84 ECU manager software (present in latest build 1.1.0.17).
Under General Setup/Fuel/Battery Comp table - when you enable the y axis (Which should be Fuel pressure?), It is fixed to Fuel Effective PW.

Cheers

Bryan

I think Motec has is right. This is how their help menu describes it.


THIS TABLE MUST BE FILLED IN - There is no other battery compensation
setting.

Compensations for various injectors may be loaded for particular injectors
by selecting 'Load Table' from the Tools menu.

The Fuel - Injector Battery Compensation normally sets the injector
'Dead Time' at various battery voltages.

The table value is a plus or minus time offset measured in usec and is
applied to the final Injector Pulse Width.

M84 has many axis locked into a default channel and can't be changed. Otherwise its an Mx00 and the price goes up. EPW is an appropriate Y axis for inj bat comp.

I understand the edit limitations of the M84 and the reasons for them, was not really concerned or trying to pass comment on those limitations, more to understand if the software was presenting an error (Which it seems Is not the case).

For my understanding and education, I understand (now) that:
The Fuel Actual PW is the summation of the Fuel Effective PW and Injector Dead time.
The Fuel Effective PW is a function of the default Injector Pulse width (IJPU) * the fuel table trim (%) plus all other compensation trims.
SO I guess this y axis in the battery compensation table would then be independent of the type of trim applied (Fuel/Air temp/Map etc) and a function of the resultant overall trim?
Did I get it?

Following on from this, how would you determine the dead time for the resultant trim levels?
I.e does the dead time for 10% fuel pressure trim have the same dead time as a resultant trim consisting of say 5% fuel pressure and 5% engine temperature (total again 10%)?

Cheers

Bryan

Can someone elaborate more on how to use Fuel EPW as Y axis in the Injector Battery Comp table?

It would definitely be much easier if MoTeC let use Fuel Pressure as Y axis on it.

Thanks

Ipe wrote:Can someone elaborate more on how to use Fuel EPW as Y axis in the Injector Battery Comp table?

It would definitely be much easier if MoTeC let use Fuel Pressure as Y axis on it.

Thanks

The opening closing of the injectors is highly dependent on the voltage that the injectors get.
So those compensations are a uniquely different approach to fuel pressure compensation.

Generally the fuel pressure is often not related the voltage, but can vary due to other reasons like fuel starvation.
So the injection timing could also benefit from having fuel pressure compensation if the pressure varies.