Electrically operated injector for gaseous fuel

1. An electrically operated injector ( 1 ) for feeding a gaseous fuel to a cylinder of an internal combustion engine, comprising:

an electromagnetic actuator ( 2 ) configured to act on a discoidal mechanical interceptor member ( 3 ) arranged to free or intercept a passage ( 4 ) for said fuel from a feed conduit ( 61 ) to a delivery conduit ( 5 ) connected to an outlet ( 6 ); and

a seal element ( 40 ) positioned between said delivery conduit ( 5 ) and said interceptor member ( 3 ), the seal element ( 40 ) being fixed to the interceptor member ( 3 ) and moving with the interceptor member ( 3 ),

wherein the seal element ( 40 ) presents a recess ( 44 ) in an end ( 42 ) of the seal element ( 4 ) which cooperates with an end ( 43 ) of the delivery conduit ( 5 ) when the injector ( 1 ) is deactivated, said end ( 42 ) of the seal element ( 4 ) being annular, and the seal element ( 40 ) is of frusto-conical shape and rests with a tapered end ( 42 ) of the seal element ( 4 ) on the end ( 43 ) of the delivery conduit ( 5 ) when the injector is deactivated and the gas passage ( 4 ) is intercepted by the interceptor member ( 3 ), the seal element ( 40 ) being fixed in a seat ( 50 ) provided in a first face ( 3 B) of the interceptor member ( 3 ) which faces the delivery conduit ( 5 ), the seal element 40 being made of elastomeric material,

and the seat ( 50 ) for the seal element ( 40 ) contains a projection ( 58 ) on which said element rests and of which it substantially copies the shape, the projection ( 58 ) presenting an annular shape having an inner wall ( 49 ) and an outer wall ( 59 ), the inner wall ( 49 ) acting as a support for the seal element when urged into closure by the interceptor member ( 3 ) which intercepts the gas passage ( 4 ).

2. An electrically operated injector as claimed in claim 1 , wherein the seal element ( 40 ) is co-moulded with the seat ( 50 ) of the interceptor member ( 3 ).

3. An electrically operated injector as claimed in claim 1 , wherein a wall ( 48 ) of the recess ( 44 ) or an inner wall of the seal element ( 40 ) has an inclination different from that of an outer wall ( 47 ) of said seal element ( 40 ).

4. An electrically operated injector as claimed in claim 1 , wherein the walls ( 49 , 59 ) of the projection ( 58 ) have different inclinations to a common axis (M) which is perpendicular to the face ( 3 A) of the interceptor member in which the seat ( 50 ) for the seal element is present.

5. An electrically operated injector as claimed in claim 1 , wherein the seal element ( 40 ) projects from the first face ( 3 B) of the interceptor member in which the seat ( 50 ) is provided.

6. An electrically operated injector as claimed in claim 1 , wherein the interceptor member ( 3 ) presents, on a second face ( 3 A) distant from the first face ( 3 B) carrying the seal element, a projecting part ( 35 ) jutting from said second face ( 3 A) and arranged to rest against the electromagnetic actuator ( 2 ) when the injector is open and the interceptor member ( 3 ) frees the gas passage ( 4 ), said member ( 3 ) being maintained at least partially detached from said actuator ( 1 ) when the injector is open.

7. An electrically operated injector as claimed in claim 6 , wherein the projecting part ( 35 ) is annular.

8. An electrically operated injector as claimed in claim 7 , wherein the projecting part ( 35 ) is separate from the interceptor member ( 3 ).

9. An electrically operated injector ( 1 ) for feeding a gaseous fuel to a cylinder of an internal combustion engine, comprising:

an electromagnetic actuator ( 2 ) configured to act on a discoidal mechanical interceptor member ( 3 ) arranged to free or intercept a passage ( 4 ) for said fuel from a feed conduit ( 61 ) to a delivery conduit ( 5 ) connected to an outlet ( 6 ); and

a seal element ( 40 ) positioned between said delivery conduit ( 5 ) and said interceptor member ( 3 ), the seal element ( 40 ) being fixed to the interceptor member ( 3 ) and moving with the interceptor member ( 3 ),

wherein the seal element ( 40 ) presents a recess ( 44 ) in a tapered end ( 42 ) of the seal element ( 4 ) which cooperates with an end ( 43 ) of the delivery conduit ( 5 ) when the injector ( 1 ) is deactivated, said tapered end ( 42 ) of the seal element ( 4 ) being annular, and the seal element ( 40 ) is of frusto-conical shape and rests with the tapered end ( 42 ) on the end ( 43 ) of the delivery conduit ( 5 ) when the injector is deactivated and the gas passage ( 4 ) is intercepted by the interceptor member ( 3 ), the seal element ( 40 ) being fixed in a seat ( 50 ) provided in a first face ( 3 B) of the interceptor member ( 3 ) which faces the delivery conduit ( 5 ), the seal element 40 being made of elastomeric material,

wherein the interceptor member ( 3 ) presents, on a second face ( 3 A) distant from the first face ( 3 B) carrying the seal element, a projecting part ( 35 ) jutting from said second face ( 3 A) and arranged to rest against the electromagnetic actuator ( 2 ) when the injector is open and the interceptor member ( 3 ) frees the gas passage ( 4 ), said member ( 3 ) being hence maintained at least partially detached from said actuator ( 1 ) when the injector is open,

and the second face ( 3 A) of the interceptor member ( 3 ) presents a seat ( 30 ) for an end ( 31 ) of a pin ( 24 ) partially inserted into an inner cavity ( 13 A) of a cylindrical part ( 13 ) of the electromagnetic actuator ( 2 ), said pin maintaining the interceptor member ( 3 ) perpendicular to its direction of movement relative to said actuator ( 2 ).

10. An electrically operated injector as claimed in claim 9 , wherein said pin is of wear-resistant plastic.

11. An electrically operated injector ( 1 ) for feeding a gaseous fuel to a cylinder of an internal combustion engine, comprising:

an electromagnetic actuator ( 2 ) configured to act on a discoidal mechanical interceptor member ( 3 ) arranged to free or intercept a passage ( 4 ) for said fuel from a feed conduit ( 61 ) to a delivery conduit ( 5 ) connected to an outlet ( 6 ); and

a seal element ( 40 ) positioned between said delivery conduit ( 5 ) and said interceptor member ( 3 ), the seal element ( 40 ) being fixed to the interceptor member ( 3 ) and moving with the interceptor member ( 3 ),

wherein the seal element ( 40 ) presents a recess ( 44 ) in an end ( 42 ) of the seal element ( 4 ) which cooperates with an end ( 43 ) of the delivery conduit ( 5 ) when the injector ( 1 ) is deactivated, said end ( 42 ) of the seal element ( 4 ) being annular, and the seal element ( 40 ) is of frusto-conical shape and rests with its tapered end ( 42 ) on the end ( 43 ) of the delivery conduit ( 5 ) when the injector is deactivated and the gas passage ( 4 ) is intercepted by the interceptor member ( 3 ), the seal element ( 40 ) being fixed in a seat ( 50 ) provided in a first face ( 3 B) of the interceptor member ( 3 ) which faces the delivery conduit ( 5 ), the seal element 40 being made of elastomeric material,

and the delivery conduit ( 5 ) comprises a plurality of portions ( 5 A, 5 B, 5 C), two of which have variable cross-sections along their axis (K).

12. An electrically operated injector as claimed in claim 11 , wherein a first portion ( 5 A) of variable cross-section lies in proximity to the end ( 43 ) of the delivery conduit ( 5 ) which cooperates with the interceptor member and has a cross-section which converges towards the axis (K) when moving away from said end ( 43 ).

13. An electrically operated injector as claimed in claim 11 , wherein the second portion ( 5 B) of variable cross-section follows the first portion ( 5 A) and diverges along the axis (K) when moving away from said first portion.

14. An electrically operated injector as claimed in claim 11 , wherein a hole for sizing the gas flow directed to the outlet ( 6 ) is provided between said first portion ( 5 A) and second portion ( 5 B) of the delivery conduit ( 5 ).

15. An electrically operated injector as claimed in claim 11 , wherein a delivery conduit third portion ( 5 C) lies between the second portion ( 5 B) and the outlet ( 6 ) and the delivery conduit third portion ( 5 C) has a constant cross-section.