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Liquid propane fuel delivery system

  • US 5,623,907 A
  • Filed: 06/09/1995
  • Issued: 04/29/1997
  • Est. Priority Date: 06/09/1995
  • Status: Expired due to Term
First Claim
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1. A liquid propane fuel storage and fuel delivery system for supplying liquid propane fuel to a vehicle-installed automotive internal combustion engine equipped with fuel injectors, a fuel rail communicating with the inlets of the injectors with the injectors being coupled in parallel between the rail and engine combustion chambers, and an on-board computerized electronic engine control unit (EECU), the engine being operable for developing driving power to the vehicle in response to vehicle-operator input control commands to the EECU, said system comprising:

  • (1) a fuel storage tank constructed to withstand interior pressures sufficient to maintain propane fuel in a liquid state in a tank interior chamber even at maximum ambient temperatures to be encountered in vehicle design operating conditions,(2) an engine fuel delivery conduit means operably coupled for communicating propane fuel between the tank interior chamber and the engine fuel injectors and including supply line means for delivering propane fuel from the tank interior chamber to the injectors via the fuel rail and return line means for returning excess fuel from the fuel rail to the tank interior chamber in bypass relation to injector output to the engine,(3) electric fuel pump means having inlet means disposed in the lowest elevation of the tank interior chamber and having outlet means operably coupled in series with said fuel delivery conduit means for pumping liquid propane from the tank interior chamber to said supply line means at a pressure above tank interior chamber pressure,(4) fuel handling means operably fluid flow intercoupled between said tank interior, said pump outlet means and said fuel delivery conduit means comprising;

    (a) solenoid-operated fuel supply valve means operable for opening and closing communication between said pump outlet means and said supply line means,(b) fuel return check valve means operable for opening communication from said return line means to said tank interior chamber in response to return line fuel pressure exceeding tank interior chamber pressure by a given pressure differential amount, and for preventing reverse flow from the tank interior chamber into said return line means, and(c) fuel return check bypass valve means operable for communicating said return line means into the tank interior chamber in bypass flow relation to said fuel return check valve means in response to a tank in-flow direction pressure differential thereacross much less than said given pressure differential operational amount of said fuel return check valve means, and also being operable as a reverse flow check valve for preventing reverse flow from the tank interior chamber to said return line means, and(5) system electronic control means (SECU) operably electrically coupled in controlling relation to said fuel pump means, said fuel supply valve means, said bypass valve means and operably slave control coupled to said EECU for automatically;

    (a) causing said pump means to be energized to deliver propane from the tank interior in a liquid state past the fuel injectors via the fuel rail and back to the tank interior chamber via said bypass valve means with a relatively high flow rate and relatively low pressure differential just prior to engine fuel delivery operation of said fuel injectors to thereby purge propane vapor from said supply and return line means and fuel rail, and(b) then closing said bypass valve means while said pump means is so energized to thereby cause said pump means to supply propane via said fuel supply valve means and said supply line means to said fuel injectors via the fuel rail in a liquid state concurrently with engine fuel delivery operation thereof and to return excess fuel flowing in the fuel rail past said fuel injectors to the tank interior chamber via said return line means and said fuel return check valve means at a return line pressure higher than tank interior chamber pressure by at least said given pressure differential amount.

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