There have been very few ruptured tanks, but when they go, they go off like a bomb. The overall number of CNG vehicles is tiny, so you arent going to see many incidents based on raw numbers. We had a CNG airport shuttle van in Los Angeles with an illegal (out of certification) tank that blew, killing someone with shrapnel, not fire. Now, factory setups for passenger vehicles require a kevlar blast blanket between the tank and passenger compartment.

Industrial/commercial handling of CNG is not as cheap and easy as liquid fuels. I did mention the HP pump to injectors in my last post. Also, look how much more a common rail diesel engine costs compared to a gasoline engine in the same vehicle, thousands of dollars more. Some of that money goes to making extra-robust components to handle higher pressures than gasoline injection. Again high pressure liquids behave differently than gasses when a failure does occur. That is why pressure vessels are hydro tested periodically, unlike plastic (or metal) gasoline or diesel tanks.

My point is that this cannot be done on the cheap like the original poster and others want.

 

o I am gonna quit asking ..lol..

 

Ok, out of the (probably) thousand CNG busses running for the past ten years, you've come up with one fatality. How many in that time have been burned alive from ruptured gasoline and diesel fuel tanks ? (there's a LOT more than one) Most of the extra cost of a diesel is not just in the injection system, but the engine components themselves to handle the higher compression ratios and turbo charging sytems, of which you cannot get around but are not a factor in a CNG conversion. Oil and gas companies have been running natural gas engines for decades in gas production, it's a cheap fuel that requires no refining to produce, what little production equipment necessary is right at the well head. You don't have to transport it to and build a refinery to use it. And the engine's don't need complicated emissions systems to deal with the exhuast emissions. It's clean, it's cheap, and it's here. There are pitfalls to everything, CNG is no more dangerous than any other fuel if handled correctly.

 

Wellhead gas is not the same as CNG refined (to remove mercury and other things), transported over pipelines and compressed at above 3000psi for dispensing into a vehicle.

Dont get me wrong, CNG as a transportation fuel is a good thing. We have had several and currently have one in our family fleet. Automobles and light duty trucks that use it are still required to have emissions equipment and testing in CA at least. It is still possible for an engine in poor tune, even running on CNG, to exceed emissions limits. We had a Crown Vic with factory CNG almost burn up its cat due to a faulty injector causing one cylinder to go way rich.

"Handled correctly" still involves much more expensive hardware than with gasoline, so the cheapness is a tradeoff.

 

what stared my quest ,was seeing used cng equipment on Kijjii and used Vic"..with all the gear for a conversion it would make sense for around town ..one of those brilliant Ideas that makes sense ,but ..yah gotta ask first ..thank you for all the info on both sides

 

Gee, I guess you missed the part about the filling stations being setup on the same pad as the well(well head gas?). And this is just getting started, as of right now, natural gas has dropped in price to where it's nearly two thirds cheaper than what it was 6-7 years ago. And leave it to California to place strict emission controls on the cleanest burning fuel we have for motor vehicles.

 

YUP!

The CARB philosophy is "maintain it factory stock and dont dare modify it". Only pure electrics are exempt. Diesels were, but now 1998 model year and later are subject to testing.

With our upcoming CO2 boondoggle (AB 32), CNG makes even more sense, but exotic and impractical stuff like Hydrogen are taking the spotlight.