Distributor fuel injection pump with precharging and pilot injection

Claim 1

IN A DISTRIBUTOR TYPE FUEL INJECTION PUMP TO COMBINATION COMPRISING: A PUMP HOUSING INCLUDING A BORE, A PLURALITY OF DELIVERY PASSAGES COMMUNICATING AT ANGULARLY SPACED INTERVALS WITH SAID BORE ADAPTED FOR CONNECTION TO FUEL DELIVERY LINES, RESPECTIVELY, AN INJECTION PRESSURE CHAMBER AT ONE END OF SAID BORE, AND A SUPPLY CHAMBER FOR SUPPLYING FUEL TO SAID INJECTION PRESSURE CHAMBER, MEANS SUPPLYING FUEL TO SAID SUPPLY CHAMBER AND MAINTAINING THE LATTER AT A PRESSURE SUBSTANTIALLY ABOVE ATMOSPHERIC PRESSURE, A RECIPROCABLE PUMP PLUNGER IN SAID BORE FOR PRESSURIZING FUEL IN SAID INJECTION PRESSURE CHAMBER, AND ROTATING VALVE MEANS IN SAID HOUSING BETWEEN SAID INJECTION PRESSURE CHAMBER AND SAID DELIVERY PASSAGES DEFINING A PILOT PORT AND A MAIN PORT CYCLICALLY CONNECTING SAID DELIVERY PASSAGE TWO AT A TIME TO SAID INJECTION PRESSURE CHAMBER DURING THE PUMPING STROKE OF SAID PLUNGER TO DELIVER A MAIN QUANTITY OF FUEL THROUGH SAID MAIN PORT TO ONE OF SAID TWO PASSAGES AND A RELATIVELY SMALLER QUANTITY OF FUEL THROUGH SAID PILOT PORT TO THE OTHER OF SAID TWO PASSAGES AND DEFINING PRECHARGING PASSAGE MEANS CYCLICALLY CONNECTING SAID DELIVERY PASSAGES IN FREE FLOW FLUID COMMUNICATION WITH SAID SUPPLY CHAMBER DURING A MAJOR PORTION OF THE TIME THEY ARE DISCONNECTED FROM SAID INJECTION PRESSURE CHAMBER.