Fuel injection systems

Claim 2

A fuel injection system of the kind comprising a fuel pump for supplying fuel under pressure, an injection nozzle including an orifice, conduit means connecting the fuel pump with the orifice so that fuel delivered by the pump will flow through the orifice, a restrictor located intermediate the orifice and the pump, a relief valve for controlling the pressure communicating with the conduit means intermediate the pump and restrictor, means defining a chamber, said chamber communicating with the relief valve and into which the fuel flowing past the relief valve can flow, and means operable when a predetermined volume of fuel has flowed into the chamber to permit unrestricted flow of fuel through the orifice.

Claim 3

The fuel injection system as claimed in claim 1 in which said chamber is defined by a cylinder containing a slidable spring loaded piston.

Claim 4

A fuel injection system of the kind comprising a fuel pump for supplying fuel under pressure, an injection nozzle including an orifice, conduit means connecting the fuel pump with the orifice so that fuel delivered by the pump will flow through the orifice, a restrictor intermediate the orifice and the pump, a relief valve for controlling the pressure intermediate the pump and the restrictor, a chamber into which the fuel flowing past the relief valve can flow, means operable when a predetermined volume of fuel has flowed into the chamber to permit unrestricted flow of fuel through the orifice, said chamber being defined by a cylinder containing a slidable spring loaded piston and, said piston acting as a valve member to open a by pass passage to allow substantially unrestricted flow of fuel to the orifice when the piston has moved a predetermined extent.

Claim 5

A fuel injection system of the kind comprising a fuel pump for supplying fuel under pressure, an injection nozzle including an orifice, conduit means connecting the fuel pump with the orifice so that fuel delivered by the pump will flow through the orifice, a restrictor intermediate the orifice and the pump, a relief valve for controlling the pressure intermediate the pump and the restrictor, a chamber into which the fuel flowing past the relief valve can flow, means operable when a predetermined volume of fuel has flowed into the chamber to permit unrestricted flow of fuel through the orifice, said chamber being defined by a cylinder containing a slidable spring loaded piston and, said piston acting as a valve member to open a by pass passage to allow substantially unrestricted flow of fuel to the orifice when the piston has moved a predetermined extent.

Claim 6

The fuel injection system as claimed in claim 3 in which the by pass passage includes a passage formed in the piston and which co-operates with a pair of ports formed in the wall of the cylinder when the piston has moved said predetermined extent.

Claim 7

The fuel injection system as claimed in claim 2 in which the restrictor is defined by a spring loaded valve member located in the nozzle and which co-operates with a seating to control the flow of fuel through the orifice.

Claim 8

A fUel injection system as of the kind comprising a fuel pump for supplying fuel under pressure, an injection nozzle including an orifice, conduit means connecting the fuel pump with the orifice so that fuel delivered by the pump will flow through the orifice, a restrictor intermediate the orifice and the pump, a relief valve for controlling the pressure intermediate the pump and the restrictor, a chamber into which the fuel flowing past the relief valve can flow, means operable when predetermined volume of fuel has flowed into the chamber to permit unrestricted flow of fuel through the orifice, said chamber being defined by a cylinder containing a slidable spring loaded piston, the restrictor being defined by a spring loaded valve member located in the nozzle and which cooperates with a seating to control the flow of fuel through the orifice, and the valve member being loaded by a pair of springs acting in series, one of said springs being stronger than the other, the arrangement being such that the valve member is moved initially against the action of the weaker spring to allow flow of fuel at the restricted rate through the orifice and is moved further against the action of the stronger spring when said predetermined quantity of fuel has flowed into the chamber.

Claim 9

A fUel injection system as of the kind comprising a fuel pump for supplying fuel under pressure, an injection nozzle including an orifice, conduit means connecting the fuel pump with the orifice so that fuel delivered by the pump will flow through the orifice, a restrictor intermediate the orifice and the pump, a relief valve for controlling the pressure intermediate the pump and the restrictor, a chamber into which the fuel flowing past the relief valve can flow, means operable when predetermined volume of fuel has flowed into the chamber to permit unrestricted flow of fuel through the orifice, said chamber being defined by a cylinder containing a slidable spring loaded piston, the restrictor being defined by a spring loaded valve member located in the nozzle and which cooperates with a seating to control the flow of fuel through the orifice, and the valve member being loaded by a pair of springs acting in series, one of said springs being stronger than the other, the arrangement being such that the valve member is moved initially against the action of the weaker spring to allow flow of fuel at the restricted rate through the orifice and is moved further against the action of the stronger spring when said predetermined quantity of fuel has flowed into the chamber.

Claim 10

The fuel injection system as claimed in claim 6 including, a first stop to limit the extend of movement of the valve member against the action of the weaker spring and a second stop to limit the extend of movement of the member against the action of the stronger spring.