Electromagnetically-operable fluid injection

An electromagnetically-operable fluid injector comprising:

• a hollow body of magnetic material;
• said hollow body having a hollow interior forming a fluid inlet chamber;
• a fluid inlet arrangement which communicates with the fluid inlet chamber such that fluid under pressure fed through it is fed directly into the fluid inlet chamber;
• an injector nozzle which is carried by said hollow body, said injector nozzle having top and bottom ends, said top end of said injector nozzle having a nozzle orifice and a valve seat formed around said nozzle orifice;
• a conduit extending from said fluid inlet chamber to said valve seat;
• said conduit having a width and communicating with the chamber at a top end and with the valve seat at a bottom end;
• a solenoid core connected to the hollow body;
• said solenoid core tapering to a substantially flat end surface;
• said substantially flat end surface projecting into said fluid inlet chamber opposite the top end of said conduit and said injector nozzle;
• said solenoid core being substantially coaxially aligned with said conduit and said nozzle;
• a solenoid winding wound around said solenoid core;
• and
• a valve of magnetic material, said valve having a width and an axial length;
• a portion of said valve having the greatest cross-sectional area of said valve in a direction transverse to said conduit being always located within said conduit;
• said valve cooperating with the valve seat to control fluid flow along a flow path from said fluid inlet arrangement through said fluid inlet chamber to said nozzle orifice;
• said valve and said hollow body including the core, being in a magnetic circuit which is magnetized by energization of the solenoid winding, the valve being a movable part of the magnetic circuit and being located in a gap which is formed in that magnetic circuit between one pole, which is formed by the solenoid core, and another pole which is formed by that part of the hollow body which forms the periphery of the conduit, the valve being normally biassed to seat on the valve seat and shut off fluid flow from said fluid inlet chamber into the nozzle orifice and being unseated to allow fluid flow along said path to the nozzle orifice and thereby to effect fluid injection by a change in the state of energization of the solenoid winding;
• said fluid inlet arrangement communicating with said fluid inlet chamber through a portion of the hollow body without passing through said solenoid core and said solenoid core flat end surface being substantially flat across its entire transverse extent, and said solenoid core end surface having a cross-sectional area substantially less than said greatest cross-sectional area of said valve;
• the width of said conduit being slightly greater than the width of said valve thereby forming a restricted gap in part of the flow path from said fluid inlet chamber to the nozzle orifice;
• the projecting substantially flat end surface of said solenoid core and the valve seat defining a dimension therebetween;
• the axial length of said valve, the dimension between the projecting flat end of said solenoid core and said valve seat, and the restricted gap between said conduit and said valve each being selected so that when the valve is fully unseated and abuts the projecting substantially flat end surface of said solenoid core, said greatest cross-sectional area of said valve is maintained within the conduit and the distance between the valve and the valve seat is greater than the restricted gap between the valve and the conduit, whereby the restricted gap between the valve and the conduit presents the greatest restriction to fluid flow so that when the valve is unseated the pressure differential urging the unseated valve towards the valve seat is substantially greater than it would be if there was no such restricted gap to fluid flow along said part of said flow path.

An electromagnetically-operable fluid injector comprising:

• a hollow body of magnetic material;
• said hollow body having a hollow interior forming a fluid inlet chamber;
• a fluid inlet arrangement which communicates with the fluid inlet chamber such that fluid under pressure fed through it is fed directly into the fluid inlet chamber;
• an injector nozzle which is carried by said hollow body, said injector nozzle having top and bottom ends, said top end of said injector nozzle having a nozzle orifice and a valve seat formed around said nozzle orifice;
• a conduit extending from said fluid inlet chamber to said valve seat;
• said conduit having a width and communicating with the chamber at a top end and with the valve seat at a bottom end;
• a solenoid core connected to the hollow body;
• said solenoid core tapering to a projecting end surface;
• said projecting end surface projecting into said fluid inlet chamber opposite the top end of said conduit and said injector nozzle;
• said solenoid core being substantially coaxially aligned with said conduit and said nozzle;
• a solenoid winding wound around said solenoid core;
• and
• a valve of magnetic material, said valve having a width and an axial length;
• a portion of said valve having the greatest cross-sectional area of said valve in a direction transverse to said conduit being always located within said conduit;
• said valve cooperating with the valve seat to control fluid flow along a flow path from said fluid inlet arrangement through said fluid inlet chamber to said nozzle orifice;
• said valve and said hollow body including the core, being in a magnetic circuit which is magnetized by energization of the solenoid winding, the valve being a movable part of the magnetic circuit and being located in a gap which is formed in that magnetic circuit between one pole, which is formed by the solenoid core, and another pole which is formed by that part of the hollow body which forms the periphery of the conduit, the valve being normally biassed to seat on the valve seat and shut off fluid flow from said fluid inlet chamber into the nozzle orifice and being unseated to allow fluid flow along said path to the nozzle orifice and thereby to effect fluid injection by a change in the state of energization of the solenoid winding;
• said fluid inlet arrangement communicating with said fluid inlet chamber through a portion of the hollow body without passing through said solenoid core and said solenoid core projecting end surface being continuous across its entire transverse extent, and said solenoid core end surface having a cross-sectional area substantially less than said greatest cross-sectional area of said valve;
• the width of said conduit being slightly greater than the width of said valve thereby forming a restricted gap in part of the flow path from said fluid inlet chamber to the nozzle orifice;
• the projecting end surface of said solenoid core and the valve seat defining a dimension therebetween;
• the axial length of said valve, the dimension between the projecting end of said solenoid core and said valve seat, and the restricted gap between said conduit and said valve each being selected so that when the valve is fully unseated and abuts the projecting end surface of said solenoid core, said greatest cross-sectional area of said valve is maintained within the conduit and the distance between the valve and the valve seat is greater than the restricted gap between the valve and the conduit, whereby the restricted gap between the valve and the conduit presents the greatest restriction to fluid flow so that when the valve is unseated the pressure differential urging the unseated valve towards the valve seat is substantially greater than it would be if there was no such restricted gap to fluid flow along said part of said flow path.

An electromagnetically-operable fluid injector comprising:

• a hollow body of magnetic material;
• said hollow body having a hollow interior forming a fluid inlet chamber;
• a fluid inlet arrangement which communicates with the fluid inlet chamber such that fluid under pressure fed through it is fed directly into the fluid inlet chamber;
• an injector nozzle which is carried by said hollow body, said injector nozzle having top and bottom ends, said top end of said injector nozzle having a nozzle orifice and a valve seat formed around said nozzle orifice;
• a conduit extending from said fluid inlet chamber to said valve seat;
• said conduit having a width and communicating with the chamber at a top end and with the valve seat at a bottom end;
• a solenoid core connected to the hollow body;
• said solenoid core tapering to a substantially flat end surface;
• said substantially flat end surface projecting into said fluid inlet chamber opposite the top end of said conduit and said injector nozzle;
• said solenoid core being substantially coaxially aligned with said conduit and said nozzle;
• a solenoid winding wound around said solenoid core;
• a valve of magnetic material, said valve having a width and an axial length;
• a portion of said valve having the greatest cross-sectional area of said valve in a direction transverse to said conduit being always located within said conduit;
• said valve cooperating with the valve seat to control fluid flow along a flow path from said fluid inlet arrangement through said fluid inlet chamber to said nozzle orifice, and the width of said conduit being nearly the same as the width of said valve so that said valve slides within said conduit;
• and
• a fluid restricting passageway bypassing the conduit having a top end, a bottom end and a minimum cross-sectional area, said passageway communicating with said chamber at its top end and with the valve seat at its bottom end and thereby providing a restriction in part of the flow path from said fluid inlet chamber to the nozzle orifice;
• said valve and said hollow body including the core, being in a magnetic circuit which is magnetized by energization of the solenoid winding, the valve being a movable part of the magnetic circuit and being located in a gap which is formed in that magnetic circuit between one pole, which is formed by the solenoid core, and another pole which is formed by that part of the hollow body which forms the periphery of the conduit, the valve being normally biassed to seat on the valve seat and shut off fluid flow from said fluid inlet chamber into the nozzle orifice and being unseated to allow fluid flow along said path to the nozzle orifice and thereby to effect fluid injection by a change in the state of energization of the solenoid winding;
• said fluid inlet arrangement communicating with said fluid inlet chamber through a portion of the hollow body without passing through said solenoid core and said solenoid core flat end surface being substantially flat across its entire transverse extent, and said solenoid core end surface having a cross-sectional area substantially less than said greatest cross-sectional area of said valve;
• the projecting substantially flat end surface of said solenoid core and the valve seat defining a dimension therebetween;
• the axial length of said valve, the dimension between the projecting flat end of said solenoid core and said valve seat, and the minimum cross-sectional area of said fluid restricting passageway each being selected so that when the valve is fully unseated and abuts the projecting substantially flat end surface of said solenoid core, said greatest cross-sectional area of said valve is maintained within the conduit and the distance between the valve and the valve seat is greater than the width of the minimum cross-sectional area of the fluid restricting passageway, whereby the fluid restricting passageway presents the greatest restriction to fluid flow so that when the valve is unseated the pressure differential urging the unseated valve towards the valve seat is substantially greater than it would be if there was no such restriction to fluid flow from the fluid inlet chamber to the nozzle orifice.