A motor vehicle fuel system operable selectively to supply metered quantities of petrol or LPG in its gaseous state to a carburetter induction passage. The LPG system includes a single stage pressure regulator and an injection valve which may be a digital or an analogue valve. The regulator operates...http://www.google.de/patents/US4513728?utm_source=gb-gplus-sharePatent US4513728 - Air/fuel induction system for spark ignition internal combustion engines, and electromagnetic valves
