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Old 22nd July 2007, 00:00   #1
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Exclamation Open loop or Closed loop - CNG / LPG

Hello all,

In pursuit of the best and most economical, yet engine friendly alternative fuel.... I came across the interesting concept of open and closed loop.

It seems most cng/lpg kits come with open loop as default and going by my friendly nieghbourhood garagewala... closed loop is nothing but waste of money.

Could someone throw some light on the advantages of closed loop versus open loop? and while we are at it... what exactly is closed loop in your opinion... sensor(ecu) + stepper or something else??

Considering the whole purpose of converting is saving on costs... how far shall one go in spending on the setup itself?

I have been quoted 45K for CNG and 24K for LPG... closed loop(only sensor and stepper motor).... which is a better deal and why.

Thanks in advance for your time and wisdom.
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Old 22nd July 2007, 13:24   #2
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CNG

Open loop system consists of Advanced Timing Sensor/Emmulator MPFI. It is a basic system which needs periodic adjustements for best performance,You also will face the Check Engine Lamp due to Lamda Error ( As the Open Loop system does not calculate the Lamda O2 Readings, but keeps on flowing the gas as required) Cannot say when , where but it will happen when tuning goes haywire.

I used mine for 9 months before TATA called me for my Lamda(Closed Loop) upgrade.

Closed Loop system has Lamda Controller ECU/Stepper Motor/MPFI Emmulator, This system offers complete automatic regulation of Gas based on Engine Requirements, It also emmulates the Lamda O2 Readings to the Main Car ECU Preventing Check Engine.

You get higher mileage, better emission readings and better pick-up, Also it does not need periodic maintaince as the Controller is self learning and adapts itself.

Ocassionally you may want to have the Controller scanned and Readings Read/Adjusted to suit you driving.

Open loop should cost you around 38,000 rupees with RTO Paperwork included and Closed loop will cost around 45-47,000 with RTO Paperwork.

I don't think its viable to move towards an Open Loop system, Closed is better anyday.
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Old 22nd July 2007, 17:25   #3
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Thanks alot wolfinstein!

Quote:
Originally Posted by wolfinstein View Post
CNG

Open loop system consists of Advanced Timing Sensor/Emmulator MPFI. It is a basic system which needs periodic adjustements for best performance,You also will face the Check Engine Lamp due to Lamda Error ( As the Open Loop system does not calculate the Lamda O2 Readings, but keeps on flowing the gas as required) Cannot say when , where but it will happen when tuning goes haywire.
Advanced timing sensor/emmulator MPFI are part of standard open loop kit?... My garagewala was asking for 3.5k extra for advanced timer... so am confused now

Quote:
Originally Posted by wolfinstein View Post
I used mine for 9 months before TATA called me for my Lamda(Closed Loop) upgrade.
Did Tata do this free of cost for you? how exactly has the performance/FE changed after converting to closed loop.

Quote:
Originally Posted by wolfinstein View Post
Closed Loop system has Lamda Controller ECU/Stepper Motor/MPFI Emmulator, This system offers complete automatic regulation of Gas based on Engine Requirements, It also emmulates the Lamda O2 Readings to the Main Car ECU Preventing Check Engine.
So no new sensor, it uses the original O2 sensor of the car?
May I request you for a closed loop checklist... what all items should be there and functionality of each of those items?

Quote:
Originally Posted by wolfinstein View Post
You get higher mileage, better emission readings and better pick-up, Also it does not need periodic maintaince as the Controller is self learning and adapts itself.

Ocassionally you may want to have the Controller scanned and Readings Read/Adjusted to suit you driving.

Open loop should cost you around 38,000 rupees with RTO Paperwork included and Closed loop will cost around 45-47,000 with RTO Paperwork.
Do you have a rough break-up of the 47k for CNG.... I have been quoted 40k for open-loop and 4k extra for closed.
Again, a checklist for items that should be there in a closed-loop kits will help ensure I get what im paying for, Thanks.

Quote:
Originally Posted by wolfinstein View Post

I don't think its viable to move towards an Open Loop system, Closed is better anyday.
I agree, Im very keen on closed loop. Are there some variants of closed loop also... like sequential and non-sequential? Any others and what are the costs/advantages...

Thanks a million wolfinstein, you have a great knowledge on the subject and thanks again for helping out!

Yuvi.
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Old 22nd July 2007, 21:54   #4
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MPFI Emmulator is a standard component of any system- Open/Closed- It emmulates the Signal to the Car ECU- On Injectors functioning, whearas actually the injectors are turned off by the system.

Advanced Timer is an Important component, although not a standard fittment for Open Loop, It advanced the Spark control in sudden pick-up or power need- This ensures you don't feel the lag and Stalling.

Emmulator cost would be included in the System, Advance Timer comes seprately for around 2000-2500 rupees, But it still would keep the Kit cost below 40,000 for Open loop/Advanced Timer/ 12 Kg tank.

TATA, Din't do it free- I paid for it earlier only I recieved the part installation later. Open loop system has a differnt wiring layout and closed a different one, It will not be possible to simply upgrade later on, as the connectors and couplers are usally built in the wiring harness itself.

After the Lamda Controller and Closed loop system, I felt the Pick-up better, Emmision control was good- The FE increased to 16.65( Now between 16.65-20.3 KM/per Kg) earlier it was around 14-15 with good pick-up but ocassional missfire.

The Closed Loop system with Lamda Control, Emmulates the Readings from the Orignal O2 Sensor in the Exhaust Manifold to the Main Car ECU.

O2 Sensor measures the Oxygen level in the Exhaust emission, It identifies if the Mixture is running Lean or Rich ( Lean meaning Good, Rich meaning Bad) This helps in preventing Check Engine-Lamda Error.

The Emmulation also functions with a Stepper Motor Module controlled directly by the Lamda Controller, This regulates the Gas flow as needed by the Engine.

The closed loop system should cost you around 45-47 K excluding RTO and Insurance Add-on cover.

Sorry I don't have the part break-up since I paid the complete amount, I guess you can Ajo for his LPG break-up and you could contact this site for Break-up estimates CNG Conversion Kits,CNG Conversion Kits Suppliers,CNG Conversion Kits India

Sequential Kits are more expensive, but are the Best features yet for the Gas Tech- It injects the amount of CNG required into each cylinder, Similar to the Functioning of the MPFI System, It calculates the Right mix of Gas and Air for a Lean Running. It also has a ECU Controller. But the cost difference is between 20-30 K over the price of a Closed Loop Lamda System.

I guess thats all you need, Oh Yes The maintainence schedule will be :

Every 5000 KM :

Inspect-Clean Air Filter
Clean Throttle Body
Inspect Spark Plugs Gap, Clean if needed and Adjust
Inspect CNG System Lines and Tank Pipe- Soap Test and Manual Inspection.

Every 10,000 KM

Replace Engine Oil ( Castrol Magnatec),If you're using Synthetic Oil then you can advance the Replacement to 15,000.

Check Air Filter-Replace if needed ( Replace at 15,000)

Check Spark Plug-Replace if needed ( Replace at 15,000)

The most important thing is that Air Filter and Throttle be clean, This ensure smooth pick-up, power- It reduces mis-fire, stalling.

Also, Start the car on Petrol, Drive 1-2 Km daily before the system switches Automatically to Gas ( Based on the RPM Setting on the Changeover switch). This ensures Petrol system functionality.

You can go through My XETA CNG Review to understand the part and Performance under CNG running.

http://www.team-bhp.com/forum/new-in...ng-review.html

Last edited by wolfinstein : 22nd July 2007 at 21:58.
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Old 22nd July 2007, 23:16   #5
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IMO,after-market closed loop installations don't seem that effective and yield negative results.
Look at Ajo's experience.
If U can get the AFR correct after some trial and error,then nothing like it.
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Old 22nd July 2007, 23:51   #6
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Ajo's system is LPG, not CNG based Closed loop,and it Defnitely has some mismatch in the ECU- The Lamda Controller ECU offered by Bedini allows you to program the setting required by a Scanner, Although offlate the ECU comes pre-programmed- The Bedini kit is the same offered on XETA/Ford Ikon/Chevy Optra, with different setting programmed for each car type.
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Old 25th July 2007, 00:51   #7
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Thanks wolfinstein. That was by far the best brief on CNG I have got so far, Thanks again.

Nitrous - Thanks to you too.

I have a few more questions for you experts... please forgive my ignorance if I sound repetetive.

(1) What is the difference between a closed loop and closed loop sequential kit?

(2) My auto workshop has recommended Bedini kit as it seems this is the only approved kit for a 1999 Lancer. This also, he will need to re-check and get back to me. Is Bedini a good kit? I was more keen on BRC...
But the workshop guy says he wont be able to get RTO clearance for the same legally.

On what basis are these kits categorised? Make? Year?? Thanks

Any other better kit recommendations most welcome.

Im srry I meantioned 1998 earlier, its infact a 1999 model.

Thanks alot once again.

Yuv
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Old 25th July 2007, 01:04   #8
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Quote:
Originally Posted by yuv
. Is Bedini a good kit? I was more keen on BRC...
But the workshop guy says he wont be able to get RTO clearance for the same legally.
Total lies!
IMO, most of the reputed kit manufacturers are the same.
Its just the installation and tuning that matters.
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Old 25th July 2007, 01:38   #9
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Quote:
Originally Posted by yuv View Post
But the workshop guy says he wont be able to get RTO clearance for the same legally.
The kits have to be approved by ARAI for getting the RTO endorsement. Not all kits are approved for all cars. Check this link.
A R A I : CMR Approved Components
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Old 25th July 2007, 19:43   #10
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Here in trivandrum saban motors are offering open looped longas kit for 21000 and closed loop longas kit for 26000. Is longas a better brand for my baleno.
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Old 25th July 2007, 20:20   #11
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Quote:
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Here in trivandrum saban motors are offering open looped longas kit for 21000 and closed loop longas kit for 26000. Is longas a better brand for my baleno.
I am doubtful whether Dars -Importers of Longas in india has approval for Baleno conversion. Check the ARAI website for more info.
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Old 25th July 2007, 20:29   #12
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I would'nt recommend Bedini..I would say Landi Renzo or Kits from Minda Impco are best suited, Based on personal feedback I have got from CNG Lancer users I happen to meet.

Bedini kits are OEM for Ford, TATA, GM Chevy Optra.

Minda Impco is the OEM for Hyundai Santro.

Although as pointed out all manufacturers make same goods and quality standards maintained are more or less same, Some how Bedini are legends in the business but are not doing good in terms of Tech advancements and products sold in India.

Besides Shrimanker the Bedini OEM Distributor is a Blatant Organisation, You may have to enquire and stand on their heads for anything at least in Delhi,Thats How the do Business

Closed Loop remains the same, Sequential system works on Gas delivery into the Cylinder, something like your MPFI system, It calculates the GAS-Air Ratio and injects it directly unlike the Conventional way of mixing in the Throttle.
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Old 25th July 2007, 22:57   #13
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Quote:
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The kits have to be approved by ARAI for getting the RTO endorsement. Not all kits are approved for all cars. Check this link.
A R A I : CMR Approved Components
Thanks alot Ajo.

I tried hard but cant seem the understand the list though...

Can you please tell me which kits are approved for Lancer 1999 model.

Thanks in advance.

Yuvi
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Old 26th July 2007, 00:30   #14
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Quote:
Originally Posted by yuv View Post
Thanks alot Ajo.

I tried hard but cant seem the understand the list though...

Can you please tell me which kits are approved for Lancer 1999 model. Thanks in advance.

Yuvi
As per list Dars (Longas), Mijo Auto gas and Ace LPG (OMVL) are approved for Lancer 99 model. Please check with installer also.
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Old 26th July 2007, 00:51   #15
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Quote:
Originally Posted by mail4ajo View Post
As per list Dars (Longas), Mijo Auto gas and Ace LPG (OMVL) are approved for Lancer 99 model. Please check with installer also.
Many thanks Ajo!

So Bedini is not approved for Lancer 1999?

Strangely enough, my installer told me that Bedini is the only kit approved for my car.... Now what do I do?

Out of the 3 kits you mentioned, which 1 is the best in your opinion?
Are they all imported... Italian?

Wolfinstein - Even my installer told me the same thing... it seems Bedini Shrimaker is really the pits when it comes to customer care and there is a problem with spare parts for their kit.... is this true? Please give your valuable opinion on the 3 kits identified by Ajo... Thanks

What if I go for Landi Renzo or Minda Impco, which I believe is not "officially" endorsed by RTO.... how would they ever know? My installer says he can manage the endorsement, unofficially though.

Thank you friends,

Yuvi
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