dogsbreath

We have a convenient BP nearby, Shell is my other preferred choice. Can anyone relate their experiences with Shell supplied gas?

Is closed loop the same as sequential or can you get closed loop with a vapour mixer as well?

zzzzz

best advice i can give is to read this and maybe understand the difference as everything depends on the type of motor and injection sysyem..

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The LPG SEQUENTIAL system is an electronically controlled gas feeding system that can be installed in all vehicles with sequential injection system. The system is a Multipoint sequential one and is controlled by an ecu that controls the gas injection sequence and the timing. The gas is injected through the rails of injectors directly into the suction pipes thus obtaining a particularly precise mix to optimise the combustion process. The gas injection timing is obtained by exploiting the petrol injection timing of the original cpu of the vehicle.This system offers the following benefits:

Compatibility with vehicles equipped with OBD systems
Optimisation of fuel consumption
Reduction in exhaust pollution substances
Optimisation of vehicle driving conditions
Installation simplicity
Auto-calibration with vehicle in neutral
Auto-diagnosis
Pre-arrangement for self-adaptation
LPG SEQUENTIAL REGULATOR
The LPG regulator-vaporizer is the single-stage type with diaphragm and is compensated by the vacuum of the suction manifold. It is designed to ensure a higher output pressure than the pressure inside the suction pipes of the engine. The engine coolant flows inside the regulator-vaporizer so that the LPG is completely vaporized. A solenoid valve complete with filter is fitted on the inlet of the regulator. A temperature sensor and a safety valve are fitted on the regulator casing.

SEQUENTIAL ECU
The SEQUENTIAL ecu is connected in parallel to the original petrol cpu. The petrol injection timing and engine rpm signals are processed by the sequential ecu and transformed into electric signals to command the injectors on the rails, thus optimising the driving conditions and fuel consumption levels of the vehicle. Once the vehicle has been converted, the installer simply connects a PC and executes the initial set-up of the basic parameters. If the dedicated map for the vehicle being converted is not available in the “data base”, the installer can still create the map for that vehicle simply by entering the parameters relative to the engine specifications. The ecu also offers other functions, such as: - It is pre-arranged for most level sensors sold in Italy and abroad. - It is pre-arranged to read all types of lambda probes. - It is pre-arranged to switch the system back to petrol automatically if there should be any anomalies in the system or if the gas runs out (the switch starts to buzz).- It is pre-arranged to analyse the anomalies recorded and to diagnose the ecu itself. -It records the time the vehicle runs on gas and records any possible anomalies encountered (these are reset when the vehicle is serviced).

RAIL OF INJECTORS
The rail sequentially dispenses the gas to each cylinder. This function is performed by separate and absolutely independent injectors, which receive the electric signal from the ecu. This signal enables the system to calibrate the amount of gas that is injected in just the cylinder in the suction phase and it also controls the cut-off function.

SWITCH UNIT
This very small electronic module is installed inside the vehicle compartment in a handy position for the driver. Thanks to its very small size it can be fitted in the place of an empty switch on the dashboard or a hole can be punched for it on the dashboard using a hot punch. The switch unit has the following functions: - It acts as a 2-position gas/petrol selector switch and indicates the fuel in use by means of two LED’s: A yellow one is lit when running on gas and a red one is lit when running on petrol. - It displays the amount of gas in the tank/cylinder by means of five LED’s: four green ones (1/4; 1/2; 3/4 and 4/4) and a red one for reserve. - It informs the driver on any anomalies encountered in the Etagas system by means of the red petrol LED that starts to flash.

HOWS THAT FOR SOME HEAVY READING

hoe

zzzzz, have you had anything to do with lpg assist diesel systems ?

i am considering this system for a couple of new hino trucks, both common rail 6 cylinder diesels, and maybe a couple of hiluxes....

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dogsbreath

Sequential - as described above is more elaborate and technical for extra gain in performance and efficiency. Unfortunately my Diesel Jackaroo is also more elaborate and technical for extra gain in its performance and efficiency -but with that has also come higher maintenance and repair costs with reduced reliability.

Z80 discusses
"Most people get the open loop system, which means that the oxygen sensor is ineffective, the mixture is set by the installer and if it goes out of spec then you need to service it. ( and it will go out of spec).
The open loop systems typically range in the $2-3000 range.

The closed loop system employs a basic electronic module that actually varies the mixture according to the usual variables as in a standard fuel injection system. This is by far the better system in terms of idle etc."

Sequential uses individual injectors for each cylinder. Virtually mimicking the petrol EFI system.

Do any of the Vapour mixer types employ a feedback system for continuous tuning or mixture control.?

I notice with my Magna that it has a standard type distributor which I would
expect would need to be advanced to a position where the car will run better on gas and ok on petrol.

zzzzz

with regards to lpg and diesel motors years ago we used to do conversions which were called torque topping but todays idea is to inject lpg into the air intake at a rate that is controled sometimes by the turbo lights and other times by throttle position.it depends on what people want to acheve..unless you are using a large amount of diesel fuel the savings would be minor..on what few i have done in past years for east-west trucks the reported savings were in the region of 10-15% of there fuel running costs.

global88

Closed loop and sequential injection use the oxygen sensor to register the air fuel mix and adjusts as necessary.
Closed loop uses a control module and controls the mixture, sequential also uses a control module at a higher level to control the time the injecter fires and the percentage of time it remains open (duty cycle).

They both have a self air/fuel mixture control.

Open loop on the other hand has a adjusted air/fuel mix set at tune up which remains at the one setting.

Now for the fun part.
As some cars are setup as closed loop setups, as the car it driven the lpg control module is adjusting the mix via the reading off the oxygen/lambda sensor.
While driving on gas the readings off the sensor are relayed to the cars factory ecu which is readjusting the mix for petrol even though the system is switched off via the dash switch.

When you switch the car over to petrol it can run rich like a dog.
Its one of the main reasons people complain that the car will only run well on one fuel.

My solution? Reset the factory ecu regularly.
Every time i reset she runs great on both fuels.

Great post on diesel/lpg zzzzz

hoe

i am spending around 8 to 15k a month on diesel atm, so 10 -15% sounds pretty good......

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z80

I just had a vapour injection system installed on a Mitsubishi 380 and it makes the open lopp system look like an absolutre piece of junk.

Cost twice as much but gets 30 percent better fuelk eceonomy.

Decapper

So in 10yrs you should have your money back Unless the government increases the tax on LPG

dogsbreath

Global88, I take it that you are running a closed loop vapour mixer system?

What steps do you take to maintain the system yourself?

global88

Closed loop vacuum mixer not sequntial injection. Old school closed loop like most of the old taxi's.

The first and most important part of getting good economy is keeping the airfilter clean.
The dirt in the air cleaner creates extra vacuum which causes extra lpg to be drawn out of the mixer and used.

I always disconnect my battery and alow the ecu to reset which helps the car run better when i switch over to petrol as part of the service/ tune.

My impco closed loop system i have has 2 mixture adjustments when tunning.

The main power valve mixture is just a large valve with L and R (lean and rich) marked on it. Its set midway factory, i have turned it one notch richer and noticed a large wide open throttle power increase at the expense of fuel economy.
I keep it midway as it provides good economy/power.

The idle mixture is the main one i play with.
My converter has a solenoid that pulses as the engine is idleing.
At the mixer is a cover with a idle mixture adjusting screw.
I use a multitester that has a duty cycle meter on it. I connect it over the solenoids terminals and adjust the air fuel miture screw until my multi reads a 50% duty cycle when the engine is warm.
If you dont have a duty meter you can turn the mixture screw one way while listening the the solinoids pulsing sound change, then go the other way till you get the same sound again then set it between the 2 settings for 50% duty.

The most important non lpg part to run lpg is the ignition system.
Make sure you have good quality leads. I use Bosch lpg compatiple leads.
The spark plugs must be in good condition, lpg prefers colder plugs so i run Xr6 plugs on my Ford. Lpg systems also prefer a smaller plug gap so i set them 0.1mm smaller.

Flush your cooling system regularly and use a quality corrosion inhibiter/ coolant, it will prevert your converter blocking up and freezing over.

Every 100,000km i strip the converter, clean it and put a fresh gasket kit though it.
Please note that the last 2 times i striped it, i found it didnt need anything, all was clean and in good condition. Most likely because i flush my cooling system and run coolant through it which keeps the system in good knick.

Every 100.000km i also replace all my mixer diaphrams, again their always fine but id rather all be in good condition.

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So disconnect battery to reset the ecu, change the air cleaner, set the idle mixture via a duty meter and mixture screw, chech ignition wires etc.

Every 3rd or so service flush coolant, change plugs.

Every 100,00km run a gasket kit through it all and maybe a new set of leads.


As a side note lpg cars prefer extra ignition timming. Ford factoy settings are 6 degrees btdc from memory, i find the car likes it 18 degrees btdc on gas but preignites a little when on petrol so i settled for about 14 degrees btdc for max power.

z80

It took a bit of digging but have found that I have a couple of cars with the "IMPCO BRC Sequent 56" LPG injection system.

Absolutely shit hot stuff.
You wouldn't know it was LPG.


http://www.brc.it/public/depl_seq_56_ta01z019-1_en.pdf

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Disclaimer:
(all my posts are my,opinions etcetera and prone to gross
errors,ommissions,lies,generalities,and more lies or prejudices as suits me on the day )

Godzilla

That was a good read.

In that link you can see the common rail with the solinoids and their individual tubes running from under them to each inlet manifold port.

The latest systems are again another step more advanced than that system.

No more converter needed before the solinoids.

Each specially newly designed solinoid is now directly bolted individually into the manifold like a petrol injecter and now is capable of vaporising the fuel at the injecter making the converter redundant and further driving down emmisions and improving economy, engine response and power.

The engine is actually more powerful now on gas than on the petrol equivalent.

Zed, when your engine is running and the bonnet is open can you hear the lpg injecters tapping away?
If not, if you put your hand on one can you feel the vibration when it operates?
Just curious to understand its characteristics, if you ever have your bonnet open could you check and post the results?

z80

LOL...I cannot tell a lie, I have only had the bonnet up once in a month.

The huge plastic engine cover obscures most of it so can't see much...

But will let you know.


I love the way it switches from petrol to gas as soon as the temperature gauge starts to rise....and i can just barely hear the click from the LPG tank as it switches over.

And not a peep out of the tacho as it does it....bloody nice !

__________________
Disclaimer:
(all my posts are my,opinions etcetera and prone to gross
errors,ommissions,lies,generalities,and more lies or prejudices as suits me on the day )

Godzilla

Forgot about that

Its there so owners can think its all sealed and take it to the manufacturer for service.

Yeah the systems are just getting better and better.....

dogsbreath

I am interested in hearing peoples opinions on the Airod closed loop vapour induction conversions. Still waiting to get my Magna done, waiting for tanks to be made apparently.
Regards Craig

z80

Will they need special storage tanks?

Godzilla

There is a serious shortage of LPG tanks (and other bits) at the moment ive heard.

z80

Just noticed that mine switches to petrol when I go open throttle.

No wonder there is no power loss when overtaking ....LOL

Godzilla

Thats strange Zed.

What makes you say that it switches to petrol on full throttle?

The system not capable of flowing enough lpg at wide open throttle?