Is a 7 seat 1999 V70 Bifuel (w/tank behind seat) workable?

[Cheradenine]

Cheers.

I guess the LPG is a bit like cigarette lighter gas; something to do with the partial pressure of the vapour I believe, but it's a long time since I looked into it.

[volvobaggen]

I think the critical pressure of the different gases is interesting to note when comparing lighter gas(butane), petroleum gas(propane) and methane

Every gas has a critical temperature. If the temperature of the gas is over this critical temperature, no amount of pressure, however great, can liquify the gas.

Lighter gas(butane) has a critical temperature of 152 Celcius, propane has a critical temperature of 96.6 Celcius. This means that liquefaction of these gases in lighters or in lpg tanks of cars is no problem at normal outside temperatures.

Methane is a totally different story, it has a critical temperature of -82,7 Celcius. This means that liquefaction is impossible in a car, only compression is possible.

[CNGBiFuel]

Essentially volvobaggen has it right. With CNG ii is at 200bar. LPG palys at it, with 20 max. Less usually. You can near as makes no differnebnce, put butan/propane in a Baked bean tin. Put CNG in a LPG toroidal tank and you don't have a tank, you have something that will take your street out! And i kid not.