Off topic:Bi-fuel

SECU-3 is able to control stepper or PWM controlled gas valve in closed loop mode - using oxygen sensor. It was finally implemented in version 4.7, but it lacks documentation

Hello.
Thank you all. It's a good news.
If you use Secu-3 micro and Secu-3 lite you don't need to add a TAP for the ignition, if you use a Secu-3t you don't need to a TAP and a control unit for the stepper motor in case of petrol/gas. Well done!

The ultimate would be to control the gas flow with a Oxygen sensor, I ran gas on a Fuel injected Audi and that controlled the gas using the Oxygen sensor but first you had to calibrate the mixer so that the Oxygen sensor was reading within its bounds, there was a red and green led and you adjusted the mixer input to get the rod led out and the green on. On a carburettor equipped car I can see the gas mix being well out of bounds so an Oxygen sensor would be good here even if you only used it for calibration.

I can't understand very well, do you mean a tool like that?

Diagnostic box lambda gas.JPG (30.83 KiB) Viewed 275 times

That's used for calibrating... I don't know what, the mixer or the control unit? However when you use the stepper motor with a mixer.
I'm thinking of regulator setting,they check the exhaust gas composition if they have got the tool, if not they adjust the flow by using their skills.
In both cases the engine is running without a high load,it's strange for me.
What can we do by ourself to get a fine tuning and to understand what parts are better in case of swapping?
The lambda probe is in the list,if we already have got a Secu-3 we can also use as a tool or a data logger.
I was still inetersting in mixers.

Mixer with venturi.jpg (59.49 KiB) Viewed 275 times

Internal.jpg (217.95 KiB) Viewed 275 times

The ventiri size can be changed if it takes, I understood why they say that it's better and so on.
I can't understand how to fit it,I'm not sure,the top is the air flow entering side,right?
It's strange because the bottom is larger than the top.
When you fit a velocity stack on a carburator the larger side is at the top.

Mixer on the carburator.jpg (355.74 KiB) Viewed 275 times

That picture is from fb factory page, I don't think they used the one for Renault from their catalogue.
I collected some examples to see the fitting way but I'm still confused.

Weber DCNF whit a mixer.jpg (164.12 KiB) Viewed 275 times

Mixer for DCNF.jpg (134.53 KiB) Viewed 275 times

The next car seems a Paugeot.

Mixer.jpg (298.59 KiB) Viewed 275 times

Regulator,stepper motor and mixer.jpg (222.87 KiB) Viewed 275 times

Doesn't take the register with the screw yet?
Other picturse are from sellers.

Mixers.jpg (107.36 KiB) Viewed 275 times

VW mixer.jpg (127.61 KiB) Viewed 275 times

That example is used often, I don't know if some parts were swapped.
I thought to use a vacuum cleaner for a comparison between a mixer on teh carburator and one between an air box and the carburator.
You must take off parts from the engine, you must buld an adaptor and add all parts as on the engine, it doesn't look a very good idea.
By a lambda probe we can see if the mixture became richer on leaner by parts swapping.
Is there a simpler way? If we use the Secu-3 to read vacuum and rpm at he idle can be enough?
Bye.

To be short. In SECU-3 algorithm which controls gas valve in general is similar to fuel injection.
On cranking:
position of gas valve determined by the Cranking PW map (this map is from fuel injection), 1ms = 1%

After cranking:
position of gas valve determined as follows.
pos = basic position from 3D map (TPS, RPM)
pos x corrections from VE and AFR maps applied
pos x warm up enrichment factor applied from Warmup enrich. map
pos x correction factor from air density map
pos x lambda correction based on value integrated from indications of narrow band oxygen sensor
pos + Acceleration enrichment correction
pos * Barometric correction (if enabled)
pos * Correction from gas pressure and gas temperature sensors (available in SECU-3i)
Fuel cut if necessary (full closing of valve)

So, SECU-3 has rich functionality. So, it is all implemented and tested by some guys, but I still need to write documentation for it I have many ideas, but I'm lacking of time.

Topic in Russian viewtopic.php?f=60&t=1235 viewtopic.php?f=11&t=195

Hello.
Congratulations! Thank you all contributors. Unfortunately it's too complicated for me.
I imagined that there must be a map like injections or ignitions but it isn't showed in any stepper control unit manual.
I didn't know that Secu 3 lite also can use a stepper module.
I can't understand why conservion kits are caslled first,second,third,fourth,fifth generation...
Often the regulator for mixers is the same for cars with carburator and injection, if there is the stepper control unit is called closed loop.
That's the last document regarding the Landi Renzo 81 regulator.

d71bc-Katalog-oborudovaniya-propan-1,2,3-pokoleniya.pdf

(2.02 MiB) Downloaded 11 times

They don't show the SE 81 SIC/A. I think the model called Renzomatic must be very old.

RENZO MATIC-RENZO LANDI.jpg (164.52 KiB) Viewed 247 times

Last month I found some files about LPG and kits but they were in russian. Why are there many vendors and documents?
I think that the SIC/A can be used for closed loop only because there is a stepper motor,I'm not sure but it doen't look a solenoid.
I found two different control units,the only difference I spotted is the stepper on the regulator instead of the solenoid valve.

lcsv05.pdf

(1.63 MiB) Downloaded 9 times

lcs-2-ita-gb-fra-spa.pdf

(2.4 MiB) Downloaded 11 times

I'm very happy that Secu-3 ecus let you use a stepper motor if you want.It can be used on all systems with a mixer.
I have some idea about gas system but I avoid to tell because I think that they can be dangerous and illegal because it takes an exam for the conversion.
Using a diffrent mixer or adding a stepper motor can be enough,when and if you can use a gas injection,sometimes I think to something mixing parts.
I found a conversion kit with an ecu like injection but I think it's used to drive a stepper motor only,there are injectors too but they don't look electronic,there is a distributor.
I think it's told about it in the russian topic at the second link of the previous post.
It was used on french Nivas,the distributor remind me the K Jetronik injection.

LPG Niva Necam GPL.jpg (198.27 KiB) Viewed 247 times

LPG Niva Necam.jpg (282.99 KiB) Viewed 247 times

Necam ecu for Niva.jpg (123.52 KiB) Viewed 247 times

Necam LPG kit.jpg (66.55 KiB) Viewed 247 times

Then there are four injectors for every cylinders on the intake manifold.

Necam injector.JPG (18.67 KiB) Viewed 247 times

They spent good words for that system but it was offered by factory cars only if I understood, there is nothing to remap the ecu. You can still find injectors and distributors as spare parts but they are very expensive.
I found a manual in french,I understood nothing.

NECAM-KOLTEC.pdf

(1.16 MiB) Downloaded 9 times

Bye.

Algorithm which I described above is 3-rd generation with some features of 4-th generation.
SECU-3i is able to perform gas injection as in 4-th generation systems (of course, using external peak and hold injector driver). Now I'm developing SECU-3i version with embedded versatile driver of low inpenadce injectors, so it will be possible to eliminate external driver.

Hello.
Well done!
I took a look at LPG and CNG FAQs but I didn't find what I need.
I found installation manuals for open loop systems.
There are two sorts of regulators for LPG and only one for CNG.

RGV.JPG (66.04 KiB) Viewed 225 times

There's written that it's for carburator,is it a pneumatic version?

160805-113932-LPG tradizionali_IT.pdf

(47.45 KiB) Downloaded 10 times

RGE.JPG (66.51 KiB) Viewed 225 times

160805-115533-LPG tradizionali_IT.pdf

(47.45 KiB) Downloaded 9 times

RME.JPG (64.75 KiB) Viewed 225 times

160826-122830-CNG tradizionali_IT.pdf

(48.13 KiB) Downloaded 8 times

The scheme for the switch with a carburator.

M200DC.pdf

(898.91 KiB) Downloaded 11 times

The scheme for the switch with petrol injection.

M200DI.pdf

(963.18 KiB) Downloaded 9 times

Those the FAQ.

160622-090952-FAQ_GPL_it_uk_R2016.pdf

(2.59 MiB) Downloaded 9 times

160622-091121-FAQ_it-eng_METANO_R2016.pdf

(2.28 MiB) Downloaded 8 times

I don't know anything of chemistry and symbols. I'd like to make a comparison between petrol and gas.
In the two FAQs there is nothing about it.
I found different values for gas stoich ratio, for petrol you can find 14,7:1,sometimes 14,5:1, for gas more options...
Bye.

Hello.
Thank you all. It's a good news.
If you use Secu-3 micro and Secu-3 lite you don't need to add a TAP for the ignition, if you use a Secu-3t you don't need to a TAP and a control unit for the stepper motor in case of petrol/gas. Well done!

The ultimate would be to control the gas flow with a Oxygen sensor, I ran gas on a Fuel injected Audi and that controlled the gas using the Oxygen sensor but first you had to calibrate the mixer so that the Oxygen sensor was reading within its bounds, there was a red and green led and you adjusted the mixer input to get the rod led out and the green on. On a carburettor equipped car I can see the gas mix being well out of bounds so an Oxygen sensor would be good here even if you only used it for calibration.

I can't understand very well, do you mean a tool like that?

No not like that, it was years ago but on the box inside the engine bay there were 2 leds and the box was connected electrically to the ECU oxygen sensor wires, you started the engine and the red led came on, you then had a restrictor/valve in the gas vapour line from the evaporator to the inlet manifold, you turned the restrictor/valve until you got a green led which showed you were at 0.5V in the 0V to 1V range of the oxygen sensor.

Hello.
Thank you. I understood. I never found a box with leds.
I found a workshop tool for cars without a lambda probe.

Set 2000.JPG (40.01 KiB) Viewed 197 times

I don't think there is something better for old systems with mixers so we can do the same job with a Secu-3 and a lambda probe.
I don't know what is written but it regards LPG.

conversion de motores a combustibles alternos-1.jpg (157.29 KiB) Viewed 197 times

I remember to have seen the same thing in another foreign language somewhere,if I'm not wrong percentages were reversed.

conversion de motores a combustibles alternos-2.jpg (155.79 KiB) Viewed 197 times

conversion de motores a combustibles alternos-3.jpg (121.77 KiB) Viewed 197 times

Is LPG composed by all those gases? Is there the method to calculate the stoich ratio in the next picture?

conversion de motores a combustibles alternos-4.jpg (89.49 KiB) Viewed 197 times

It would have been better to write the value of each gas. Unfortunately they don't tell the percentages of the mixture at the service stations.
The capacity of LPG tanks is in liters of water,perhaps to avoid confusion with m^3.
You can refill them till 80% so the liters of LPG allowed are 80% of water liters.
That's what happens in the tank.

LPG tank.JPG (82.2 KiB) Viewed 197 times

Somewhere it's written 85% or 75%.

carburants_bac.pdf

(64.35 KiB) Downloaded 9 times

gpl1_generalites.pdf

(71.15 KiB) Downloaded 10 times

They're in french,they seems the tell the same thing,maube you can find similar documents in your native language.
There are charts with many values I don't know.

LPG-Propane-Butane.JPG (38.92 KiB) Viewed 197 times

PROPAN-BUTAN-BENZIN-DIESEL.JPG (53.66 KiB) Viewed 197 times

I'm interesting in octane number, stoich,consumption and power,nothing else.
On LPG VE is a little bigger than petrol,possible? Did I misunderstand?
Bye.

Hello.
A personal project regarding a mixer.

CNG mixer 1.JPG (31.59 KiB) Viewed 171 times

CNG mixer 2.JPG (23.06 KiB) Viewed 171 times

CNG mixer 3.JPG (16.2 KiB) Viewed 171 times

CNG mixer 4.JPG (25.64 KiB) Viewed 171 times

The rubber part on the carburator of the red Niva is from Renault 12, the carburator from Peugeot 504,the mixer is 63mm, I don't know the size of the venturi.

Bocina de carburador Adon Renault R12-1.6-l-1990-1994-.jpg (28.05 KiB) Viewed 171 times

I meet that sort of mixer often.

Mezclador GNC-Ford Taunus.jpg (91.47 KiB) Viewed 171 times

The same for the rubber part from R 12.

Ford GNC mezclador.jpg (13.15 KiB) Viewed 171 times

I didn't understand if they use Sierra mixers on Taunus or vice versa.

Mezclador Ford Sierra.jpg (98.04 KiB) Viewed 171 times

The owner of that red Sierra tried that mixer and another one for the OEM air box.

Mezclador GNC-Ford Sierra.jpg (90.71 KiB) Viewed 171 times

Another person used a system like the one above. He was satisfied till he had some problem owing to the breaking of rubber part on the carburator.

Ford Sierra CNG mixer.jpg (72.83 KiB) Viewed 171 times

Finally the owner of the red Sierra preferred the standard OEM air box.

The air box adapted for the mixer.

Ford Sierra air box.jpg (57.41 KiB) Viewed 168 times

Ford Sierra CNG mixer.jpg (60.59 KiB) Viewed 168 times

Perhaps the mixer is for Taunus on the catalogue.

Ford Sierra air box cap.jpg (42.24 KiB) Viewed 168 times

Ford Sierra engine bay.jpg (80.64 KiB) Viewed 168 times

The ultimate test is what he preferred.
I found an old Lada Niva brochure.

Lada Niva LPG-GPL in France.JPG (595.64 KiB) Viewed 168 times

It was written that the bochure is of 1989,September, somewhere 1990 or 1991.
It seems that the LPG version was introduced in 1988.
Nothing regarding the LPG system,maybe it' interesting for Niva fans.

Niva-1.pdf

Lada m geschiedenis final

(2.78 MiB) Downloaded 10 times

Niva-2.pdf

(2.23 MiB) Downloaded 10 times

Niva-3.pdf

(817.64 KiB) Downloaded 12 times

The next is a Niva brochure,there are power and fuel consumption running on petrol and on LPG.

brladniv77.pdf

(1.87 MiB) Downloaded 8 times

Probably is the injected one fitting the Necam/Koltec LPG system.
I found the Koltec manual in russian.

koltec.pdf

(948.28 KiB) Downloaded 9 times

Bye.