Dual fuel, pressure adjustment

[puntogt4]

I think is a problem with dual fuel and pressure correction, I have a 350 kpa sensor on the lpg rail is a absolute model
When running I have a delta of 110kpa from map and lpg pressure, this is set from my lpg pressure rugulator landi renzo
I try to see the value of fuelpress2 but I see is so very strange and wrong value, I try to use all 3 type of sensor on dual fuel menu gauge, absolute and differential
but for each type I have a wrong reading of real fuel delta pressure, in attach thr msq and the 3 datalog

on this tred James write:

Correcting previous post, the number used is:
df_press = { sensor01 +barometer - map }
df_temp = { sensor02 }

http://www.msextra.com/forums/viewtopic ... nt#p305321

But reading my datalog is out!!! case gauge setting: by math, I have fuel 144.9kpa + baro 96.9kpa - map 37.2kpa = 204.6 kpa???
but log show 86.8kpa!!!
Francesco

[puntogt4]

After reading the log of differential I notice is the more reable to work,
I can ad around 90-100kpa at the fuel sensor on generic sensor IE, I have now
@ 0volt= 5.5kpa
@ 5volt= 389kpa
if I write:
@ 0volt= 102.4kpa
@ 5volt= 485.9kpa
I have the right value on fuel pressure and I can use the table for correction!!

[puntogt4]

Looking the dual fuel pressure adjustment on the picture is visible there are something wong,
the fuel pressure 2 is a mirrored on X respect the map and fuel pressure sensor value, when increase map decrease the fuel press2!!
My queation is if nobody have use dualfuel?
How is bossible this? the previus beta have the same bug?
An other question, is possible to implement a "AND" function on the imput of dual fuel?
traditional sistem if rea a delta pressure low disengage the LPG and jump to gasoline to prevent lean condition
and Landi on is ecus for turbocharged engine use the petrol injecto to help the engine undel high load
How we can menage this? by reading on the board I see is possible if I set the LPG fuel like first and gasoline second but I lose the fuel correction?
Is possible to use the dual table?
Dual Table = parallel fuel tables allowing simultaneous control of both fuels. e.g. mapped methanol under boost.

[jamies]

Is your LPG regulator referenced to the intake manifold, or is there no vacuum/boost line connected?

[puntogt4]

Is your LPG regulator referenced to the intake manifold, or is there no vacuum/boost line connected?

Like you can see on the picture is connect to the intake manifold and it follow very well the map signal, maintaining a right delta pressure
If I left pen the regulation pipe I don't have a good pressure to work on boost region

[Marek]

Asking for the petrol injectors to be operating when the lpg injectors are also operating isn't a great idea.

The primary reason you'd want this is because you don't have sufficiently large lpg injectors or don't have a reducer with sufficient surplus capacity such that you cannot deliver enough fuel under heavy load. In this case what you need is heavier duty components.

The secondary reason you may want this is that you have soft valve seats and need the lead in petrol to prevent valve seat recession. To ask for a tiny amount of petrol to also be injected, you need to very accurately define the injector deadtime and you are unlikely to succeed in this to achieve your goal which would be a (for example) 95% lpg. 5% petrol mix - the petrol injection time will simply be too short to be accurate or meaningful. I suggest you instead get a valve saver oil feed installed like all soft valve lpg installations have.

Thirdly, some lpg users will have a set up which is switched via relays and use the same injector channels for both fuels. Clearly the "and" condition can't work them.

Lastly, to troubleshoot such a setup will be a nightmare. Also, how exactly will injector trim be applied?

kind regards
Marek

[puntogt4]

[quote="Marek"]Asking for the petrol injectors to be operating when the lpg injectors are also operating isn't a great idea."

I'm not agree with You

"The primary reason you'd want this is because you don't have sufficiently large lpg injectors or don't have a reducer with sufficient surplus capacity such that you cannot deliver enough fuel under heavy load. In this case what you need is heavier duty components."

No I have a biggest reducer is more than I can use and the line from tank is bug too also tha main valve on tank is the bigger One and the injector are the white Bosch can delivery fuel to 170kw turbo engine

" The secondary reason you may want this is that you have soft valve seats and need the lead in petrol to prevent valve seat recession. To ask for a tiny amount of petrol to also be injected, you need to very accurately define the injector deadtime and you are unlikely to succeed in this to achieve your goal which would be a (for example) 95% lpg. 5% petrol mix - the petrol injection time will simply be too short to be accurate or meaningful. I suggest you instead get a valve saver oil feed installed like all soft valve lpg installations have."

no, I have heavy valve seat My is a C20LET engine and I have a complete data of My set of gasoline and Lpg injecort, Then I can work togheter with no issue, If You say gasoline is a liquido and when sprayed into the cilynder it go in a vapur of gasoline and this substract energy ( temperature ) from engine mixture, for this reason many modern engine with Lpg or CNG dual fuel are using both fuel at same time, when going into boost region obviously not in a mixture of 5gasolin and 95 Lpg but more than 60-80% gasoline and reat of Lpg!

"Thirdly, some lpg users will have a set up which is switched via relays and use the same injector channels for both fuels. Clearly the "and" condition can't work them."

This dipende of each istallation, may be they have a differenti injector, I have low impedance for Lpg and high impedance for gasoline, and I have a custom espansione PCB that provider to drive alla injector, this is only a improvement for people have separate injector channel

"Lastly, to troubleshoot such a setup will be a nightmare. Also, how exactly will injector trim be applied?"

For this reason whe need a right data to work, If I and other people have a 4 egt One per cilinder is very easy to set-up, in case of people don't have rigth data they use the BASIC setting or upgrade their istallation

sorry If My english appear confuse but My english
is not the best and My phone do the rest!!!

francesco

[puntogt4]

I have try a lot of configurazione but nothing is working for me! here nobody have a functional fuel pressure correction in working condition?
Francesco

[jsmcortina]

Only just got to look at this.

In the MSQ you posted, you Generic Sensors configuration has:
Sensor 01 = lpg pressure
Sensor 02 = lpg temp

However... on the Dual Fuel screen you have:
Temperature on = Sensor 01 (WRONG ONE!!)
Pressure in kPa on = Sensor 02 (WRONG ONE!!)

The two inputs are transposed.
The pressure input is also configured as "Gauge" but you say you are using an Absolute sensor.

Perhaps you've already fixed these in later testing.

I've re-tested on the bench and the "Fuel Pressure 2" looks to be an accurate representation of the differential rail pressure. (Although wasn't there some mention somewhere of choked flow?)

James

[puntogt4]

I have to fix this, swap input!!! OK
but for the accelerazione? di you see the all 8 injector are firing during accelerazione?

[jsmcortina]

I have to fix this, swap input!!! OK
but for the accelerazione? di you see the all 8 injector are firing during accelerazione?

I have not tested that yet. I will.

James

[puntogt4]

ok, here the last msq with the right sensor setting!

[jsmcortina]

ok, here the last msq with the right sensor setting!

How does it run now?

James

[puntogt4]

ok, here the last msq with the right sensor setting!

How does it run now?

James

Now with the correctoion working very better, remaninig the problem with the accelleration,
specially at cold condition with the 8 injector firing the engine is undriveble

in attach a screenshot where we see the duty 1 end duty2 when accelleration income, I can't attach the log because is to big 9mb

[jsmcortina]

I am not able to replicate a problem here.

I've tested with 1.4.0 release, pre-1.4.1 beta1 and the latest dev code. In all cases, the TPS-based acceleration only adds fuel to the bank of injectors currently in use. (EDIT: Although it might make more sense if the second bank were logged as Seq PW5,6,7,8.)

I confirmed this on the stim (tweaked MSQ for 36-1 bench setup, pot input for MAP and switch input for switching.)

James