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Posted

LPG or CNG? LPG is pressurized to 250 psi, CNG to 2500 psi. Propane/butane vs methane/ethane.

It's a bit of a myth CNG is cheaper to run, due to annual tank checks and extra engine wear. The environmental benefit is marginal with LPG, because the carbon: hydrogen ratio is slightly less than gasoline. The engine is still burning a fossil fuel.

 

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Posted

So, petrol is more likely to catch fire in the event of exposure to a hot exhaust system.

The popular TV show, Fifth Gear, decided to test which fuel was safer in the event of a fuel system leak. 

They simulated leaks that filled the car with fumes and then ignited it. 

The result with LPG was a veritable flash in the pan compared to when petrol fumes destroyed the entire back of the test car.

https://www.elgas.com.au/blog/722-are-lpg-cars-safer-than-petrol

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Posted

Generation IV – sequential gaseous stage LPG injection

These are made to convert spark ignition engines with multipoint fuel injection (with lambda sensor, catalyser and EOBD system). Right now 4th generation systems are the most popular and most precise ones among all systems delivering gaseous stage LPG to combustion chambers of the engine. Fuel is injected into each intake manifold line individually, near the valves, through electromagnetically operated injectors. These are controlled by an ECU which – using only petrol injectors control signals and rev speed signal – calculates injection times for the autogas system. Fourth generation systems do not require any other signals from the engine's sensors, because – unlike previous generation systems – they are not parallel systems. This means the autogas ECU only recalculates

petrol injectors signals from the original ECU into appropriate signals for the LPG injectors. The entire engine functioning strategy is actually executed by the petrol ECU, all diagnostic systems run normally and there is no need to use any external emulators (injector emulator is integrated into the gas ECU).

Fuel feeding place: sequential autogas injection into intake lines of individual cylinders, near the valves.

State of fuel delivered to the engine: gaseous

Regulation: electronic – LPG injection time is calculated on the basis of petrol injection times.

Application: spark ignition engines with multipoint fuel injection, lambda sensor, catalyser and EOBD system.

Advantages: very precise fuel dosage, ease of conversion.

Disadvantages: relatively high price.

https://gazeo.com/automotive/technology/Autogas-system-generations,article,6486.html

 

Payback for our system - at 25,000 THB, was aprox 18 months

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Posted
1 hour ago, VocalNeal said:

But you don't mind having the rear seat passengers sitting on 45-50l of gasoline?

 

Not keen on that either but needs must

Posted
12 hours ago, canthai55 said:

Nothing wrong with LPG or CNG

What is wrong is the complete and utter lack of preventive maintenance

Our LPG car fuel costs per Km is 50% of cost per Km on gasoline

Disagree. You think the cylinder head temperature of 600 C with CNG will result in the same engine wear as gasoline with a cylinder head temperature of 260 C? Do you believe in the tooth fairy as well?

Posted (edited)
21 hours ago, Lacessit said:

LPG or CNG? LPG is pressurized to 250 psi, CNG to 2500 psi. Propane/butane vs methane/ethane.

It's a bit of a myth CNG is cheaper to run, due to annual tank checks and extra engine wear. The environmental benefit is marginal with LPG, because the carbon: hydrogen ratio is slightly less than gasoline. The engine is still burning a fossil fuel.

 

I never knew that +2 thanks

 

Fossil fuel yes, but far cleaner.

 

Annual tank checks in Thailand?

Edited by Number 6
Posted
2 hours ago, Number 6 said:

I never knew that +2 thanks

 

Fossil fuel yes, but far cleaner.

 

Annual tank checks in Thailand?

Cleaner with respect to a sooty exhaust, but very little difference in carbon dioxide emissions for LPG.

I can't remember if it is 5 or 10 years for LPG tank checks. Definitely one year for CNG, due to the high pressure. Registration renewal won't happen without a certificate from the tank inspection shop.

I seem to remember some ambassador in Bangkok had a CNG vehicle explode, don't know whether he was in it.

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Posted (edited)
11 hours ago, Lacessit said:

but very little difference in carbon dioxide emissions for LPG.

Yes but what about the other pollutants, which are less.


 

Quote

 

, pollutants in LPG mode are reduced for:

 CO by 30% in urban cycle and by 10% in extra urban cycle,

 HC by 30% in urban cycle and by 51% in extra urban cycle,

 NOx by 41% in urban cycle and by 77% in extra urban cycle and

 CO2 by 10% in urban cycle and by 11% in extra urban cycle.

 

Quote

The Southwest Research Institute in San Antonio, TX has conducted numerous studies on propane emissions and determined that using propane cuts smog producing exhaust by as much as 70 percent. Propane engine exhaust is so clean and friendly to the environment that propane powered forklifts operate inside warehouses throughout the world. 

 

Edited by VocalNeal
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Posted

I do worry about the non factory fitted gas systems. ie aftermarket fitting. Don’t know how well they are installed / tested. For the price of petrol here I’d rather have the extra space.

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Posted
On 1/13/2020 at 7:35 AM, transam said:

Gasoline is not stored under pressure...........

But in a very thin tank that can rust out. LPG tanks are thick and must be replaced every 10 years.  

Posted
4 minutes ago, brianthainess said:

But in a very thin tank that can rust out. LPG tanks are thick and must be replaced every 10 years.  

Very thin tank because it is not under pressure. As for rust, so what, how many rusted out tanks have you had..?...????

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Posted
12 minutes ago, Jaxxper said:

I do worry about the non factory fitted gas systems. ie aftermarket fitting. Don’t know how well they are installed / tested. For the price of petrol here I’d rather have the extra space.

There are some reputable company's out there, with free follow up check ups. you can also get doughnut tanks that fit where your spare wheel is.

Posted (edited)
9 minutes ago, transam said:

Very thin tank because it is not under pressure. As for rust, so what, how many rusted out tanks have you had..?...????

I have seen many in 40 yrs working in the trade.

Edited by brianthainess
Posted
15 minutes ago, brianthainess said:

I have seen many in 40 yrs working in the trade.

Perhaps, but if it were an issue there would be legislation to cover it, but there ain't. 

I personally have never had an issue with a rusted out tank, even the period when cars fell apart via rust mid last century..????

Posted
48 minutes ago, Jaxxper said:

I do worry about the non factory fitted gas systems. ie aftermarket fitting. Don’t know how well they are installed / tested. For the price of petrol here I’d rather have the extra space.

From the 10 second examination I made of the tank area it was black ice cold filled the spare wheel well the quality of the installation looked ok but what do I know ! if you have ever watched the film Snatch I moved as fast as the big rabbit before I got ******

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