Systems and method for delivering liquified gas to an engine

A valve device for a liquified gas delivery system, the valve device comprising:

• a housing defining a first chamber and a second chamber, the first chamber configured to receive liquified gas from a holding tank and the second chamber configured to receive liquified gas vapor from the tank;
• a proportioning spool disposed between the first and second chambers, the spool including a head portion disposed in the second chamber and a stem portion that extends into the first chamber;
• a shunt port in the stem portion, the port communicating with a shunt channel that passes through the head portion;
• means for regulating the flow of liquified gas through the shunt channel;
• and
• means for positioning the spool within the first and second chambers;
• wherein the valve device is adapted to proportion fluid flow to an engine between an all gas phase fluid comprising liquified gas vapor and an all liquid phase fluid comprising liquified gas, while directing available excess liquid phase fluid back to the tank for maintaining an operating pressure therein.