Thread: NGV conversion - How safe in an accident

NGV How safe in an accident in LOS


Fuel Economy and Range

A cylinder of lets say 50-water liter capacity holds approximately 11.76-cubic meter of CNG that is in the range of 13-14 liters of petrol equivalence. A small-sized car that is powered by a 1300 CC engine will have a mileage range of about 150-160 Km per cylinder.

This is the standard of fuel comparison test which is far too complicated.

NGV is cheaper but how far will 1000Baht of NGV take me in comparison to Diesel or Petrol (Gas)

CNG (NGV) conversion

CNG is filled in the cylinder up to a maximum pressure of 200 bars that’s about 3600 psi.

That is a lot of pressure. Scary amount if you think about it and is Khun Somsak the right guy to install the conversion. Combustion is a science. So what is the effect if I was mad enough to fit a silly big bore exhaust system on the conversion or when the ECU has been modified or a second turbo added.

Is there any guidelines for Khun Somsak: is there any guidelines at all?

Accidents

So what is the risk in an accident, has there been any tests on safety and is there any information available, are the Thai rescue people aware and able to cope. Would they know the vehicle is running on NGV and would they know the priority of shutting off the valves and cooling the cylinder.

CNG or NGV just rises up and dissipates into the atmosphere. Its self-ignition temperature of 700C is much higher than that of petrol (455C) so to some extent it is safer.

CNG needs to mix with air within a small range of 4-14% by volume for combustion to take place. This is a far narrower range than for petrol which is not so good.

Originally Posted by gjbkk

NGV is cheaper but how far will 1000Baht of NGV take me in comparison to Diesel or Petrol (Gas)

Not sure if it is true or not, but we had a Thai lady tell us that it only cost her 100 baht to drive to Bangkok from Pattaya.

I am pretty sure you can't convert diesel to NGV. Anyone sure about this?

Originally Posted by chitown

Originally Posted by gjbkk

NGV is cheaper but how far will 1000Baht of NGV take me in comparison to Diesel or Petrol (Gas)

Not sure if it is true or not, but we had a Thai lady tell us that it only cost her 100 baht to drive to Bangkok from Pattaya.

I am pretty sure you can't convert diesel to NGV. Anyone sure about this?

you can but some quantity of diesel must be used as lubrication. Turbos do cause a problem and I do not have any info on this yet

Originally Posted by gjbkk

Its self-ignition temperature of 700C is much higher than that of petrol (455C) so to some extent it is safer.

I think you will find that should be Fahrenheit not Celsius

It would be quite a project to convert diesel to CNG, You would have to engineer a system to get the fuel into the cyl. then an ignition system would have to be built and as was mentioned a top oiling system would have to be added.
CNG can be aspirated naturally or turbo charged into the cyls tho.
I have no idea how they get it into an injected engine tho, all this EFI shit has came about since I fooled with cars, and I have been around heavy duty engines that ran on Butane/propane, The old Hall Scott was one such engine that performed very well on conversion from gasoline to Butane and they were 450 HP in trucks back in the early 50s and before.

Originally Posted by chitown

I am pretty sure you can't convert diesel to NGV. Anyone sure about this?

In diesel engines, CNG can be used either as a dual fuel or mono fuel. In dual fuel mode, diesel provides combustion initiation for CNG burning.
CNG can be used as a mono fuel by converting the diesel engine to a spark ignition engine. This conversion warrants major changes in the engine and the operation of the vehicle becomes CNG-dependent.

Originally Posted by blackgang

a top oiling system would have to be added.

Sorry, could you explain that bit to me.

Originally Posted by Thetyim

I think you will find that should be Fahrenheit not Celsius

I think so too, and I do not know about self ignition of gasoline, but I do know that it does vaporize and will flash at 50+ degrees F.

Originally Posted by Thetyim

Sorry, could you explain that bit to me.

Yes, as far as I know any diesel engine does reguire some oiling of the upper cyl. and this is accomplished by the diesel fuel, It does lubricate the rings and prevents blow by which in turn would score the cyl. if you ran a diesel engine on straight gasoline for a very short time the cyl liners would be scored by the rings.
Marvel mystery oil company built a top oiler for internal combustion engines way back when and any engine that ran one would get a hell of a lot more miles before tead down than those without.
Plus this upper cyl lube does lubricate the valve stems too, which was a part of the job done by lead fuel additives. thats the reason that when they switched to unleaded fuel they also had to change valve stems to selenium to stop that wear of valves and guides.

IMHO

We're contemplating going CNG with our diesel Fortuner - Problem is, they said we have to chuck the spare wheel as that is where the tank will go.

Our friends with a Honda accord get 130kms for 60 baht.

A brand new Honda CRV convert caught fire and was written off about 6 months ago in front of my mate's business.

Originally Posted by Gallowspole

Problem is, they said we have to chuck the spare wheel as that is where the tank will go.

Can you hang the spare wheel off the back bumper ?

Do you mean on a swing bar kind of thing? (sorry I'm not very practical so not versed in technical language.)

The idea was floated about putting the spare on the back hatch (like the CRV but that has a vertically hinged door as opposed to the Fortuner which has a horizontal hatch) - but 2 thoughts arose: would the wife be able to lift it up and would it support the added weight?

I think it is called a wheel carrier.
I agree with you do not hang it on the rear door.
Get the hinged one

LPg wears out the valves on paetrol as well as diesel engines ( as I know to my cost when i had to have a new cylinder heat fitted on my LPg converted lexus soarer)

As far as the original enquiry regarding safety===well the thickness of the wall of the lpg tank is far more than any petrol tank I ever saw.
Unless you do megga miles the conversion is not economically sound

why not run a diesel on cooking oil/diesel mix ?
my freind runs a small peugeot on cheap veg oil/diesel mix no problem
he saves about one third in costs

Originally Posted by paulsmithson

LPg wears out the valves on paetrol as well as diesel engines ( as I know to my cost when i had to have a new cylinder heat fitted on my LPg converted lexus soarer)

Something not quite right there.
Why did you need a new cylinder head if the valves were worn ?

Originally Posted by Thetyim

I think it is called a wheel carrier.
I agree with you do not hang it on the rear door.
Get the hinged one

Thanks - it's all food for thought at the moment but the cost of driving 600k a week is now having a detrimental effect on my beer budget. Decisions, decisions.

Originally Posted by Thetyim

Originally Posted by paulsmithson

LPg wears out the valves on paetrol as well as diesel engines ( as I know to my cost when i had to have a new cylinder heat fitted on my LPg converted lexus soarer)

Something not quite right there.
Why did you need a new cylinder head if the valves were worn ?

he got ripped off?

^ The Thai Police in Bangkok run a veg oil mix in their utes.

The diesel engine was originally invented to run 100% on vegetable oils.
However with diesel at 40 baht per litre and ( my wife tells me) cooking oil at 47 baht I stick to diesel.
Four good sized coconuts will produce one litre of bio fuel I am told.
May try producing my own as coconuts are plentifull where I live and the challenge will be interesting,

The reasdon I had to have a new cylinder head after running my Uk car on LPG was that the valves and guides were totallty burned out. I do believe that someone now markets a kit which supplies extra lubrication for the top end to overcome this problem.

Originally Posted by Thetyim

Originally Posted by gjbkk

Its self-ignition temperature of 700C is much higher than that of petrol (455C) so to some extent it is safer.

I think you will find that should be Fahrenheit not Celsius

yes you are right, my mistake

Originally Posted by Gallowspole

We're contemplating going CNG with our diesel Fortuner - Problem is, they said we have to chuck the spare wheel as that is where the tank will go.

Our friends with a Honda accord get 130kms for 60 baht.

A brand new Honda CRV convert caught fire and was written off about 6 months ago in front of my mate's business.

"chuck the spare wheel as that is where the tank will go" has anybody tested the safety of that.

I would be worried of a truck slamming into the back

I read some were you have to use a 50% diesel to 50% GNV mix after conversion the vehicle can run on 100% diesel also.