batch fire of injectors - VLT

[brett_32i]

hopefully a quick one..

just wondering if this is done through the hardware of the ECU, or the software?

what is the determining factor that switches to batch fire and is it adjustable?

[streetbike]

It is a shame but it is only hardware it depend mostly of the injection time, when it is more then 8-10ms it switches to batchfire .....

typicaly on my car with 550cc it comes at 2600rpm and with the 1600cc it comes at 4000rpm ..

[Matt]

There was found a switchover parameter between batch/sequential for this ECU. One of the tuners had looked into the code for this. Havent tested it out yet

[streetbike]

Very interesting thing Matt !!! is it working on ca18det ??

[Matt]

Havent looked that far yet. Once I have a play around with VLT then CA18 would be the next candidate due to people having injection drops during the switchover

[skyline_stu]

Changeover is based on RPM, TP & coolant temp

Coolant temperature was an important input to determine batch or simultaneous mode too.

I had to run the ECU in batch mode for compatibility with the LPG system (imagine the problems when a multipoint LPG setup monitors Injector duty for load determination - and then it changes to from simultaneous to batch mode under boost)..

I ended up rewritting the firmware, installed it in a twin table chip, set it to 100% batch mode when on LPG (allows finer tuning resolution), then tuning the LPG's controller to suit the resulting duty cycle

It was a HUGE amount of work, but far cheaper than the client burning a hole in his piston..

@Streetbike *** Remember that changing the K constant changes calculated TP ***

Stu

[bachig24u]

There was found a switchover parameter between batch/sequential for this ECU. One of the tuners had looked into the code for this. Havent tested it out yet

There was found a switchover parameter between batch/sequential for this ECU. One of the tuners had looked into the code for this. Havent tested it out yet

Hi Matt,
Do you have the rom value for this parameter that i could edit code directly?

We've been seeing lambda spikes at specific rpm's with various injectors 'constants'. This is not a good place to be when pushing 40lBs inlet absolute pressure.
Moving the PAU load application to higher rpm's or increasing convertors stall speeds, redesigning inlet manifolds and the issue isn't noticed.
Monitoring injector pulses directly from individual looms show the sychronization amoungst cylinders just after lamdba spikes.

Our workaround is time consuming and expense, not a practical solution for the general street vehicle application.

p.s good to see some stability in 0.10.11 (up for a few weeks now

[Matt]

Stu who posted before has the parameter and I have a copy but havent checked it out yet. When I get some time after my break it will be something to look at again

[skyline_stu]

Water Temp is &3FD5, as is its set to 40'c
TP changeover is at &3FDB , currently 60h (96d)

Be careful with these as they are very powerful scalers.

[skylinegtrhr]

Water Temp is &3FD5, as is its set to 40'c
TP changeover is at &3FDB , currently 60h (96d)

Be careful with these as they are very powerful scalers.

Hi Stu and thanks for these but do You by any chance have water temp & TP change over for CA18DET?

Thanks in advance and sorry for little OT

[streetbike]

on the CA18DET it is also based on RPM

I have tested lots of injectors on my car and for what I have seen it is TP based but if TP is not achieved until 4000rpm it force change to batch fire

with 440cc it was at 3000rpm and 10ms pulsewidh,
with 550cc it was at 3500rpm and 10ms pulsewidh,
with 700cc it was at 4000rpm and 10ms pulsewidh
with 800cc it was at 4000rpm and 9ms pulsewidh
with 1200cc : 4000rpm and 7.5 ms pulsewidh

of course never tried this below 80°C ....

[skyline_stu]

That sounds plausable - because as you change the K constant, the active point on the map moves further left.

I haven't tested it on a CA18 ecu - I'd need to set up my test rig for that.. We'll see how my time goes over the rest of the week..

[bachig24u]

Water Temp is &3FD5, as is its set to 40'c
TP changeover is at &3FDB , currently 60h (96d)

Be careful with these as they are very powerful scalers.

Thanks Stu

[bachig24u]

CR31 and VLT ECU's and RB20DET 23710-11U00/04U60 will only ever work in batches of 1,5,3 and 6,2,4.

[skylinegtrhr]

That sounds plausable - because as you change the K constant, the active point on the map moves further left.

I haven't tested it on a CA18 ecu - I'd need to set up my test rig for that.. We'll see how my time goes over the rest of the week..

Hi Stu again, did You by any change test CA18 engine?