Abstract: A spark plug comprises an electrically-insulating sleeve (12) extending along a central axis (14) of the plug, a first electrode (16) having a tip (20), an electrically-conducting shell (22), and a second electrode (26) mounted on the shell, the second electrode having a tip (28). The tips (20 and 28) have spark surfaces (30, 32) which define a spark gap (34) of the plug. The spark surfaces (30, 32) are inclined at different angles (?1, ?2) relative to a plane (36, 38) extending normally of said central axis (14) of the plug so that said spark gap (34) varies in width along the length of the gap with the narrowest point (X1) of the gap being further from the connection between the second electrode (26) and the shell (22) than the other end of the gap.

Abstract: A spark plug (30; 40) comprises an electrically-insulating sleeve (12), a first electrode (16), an electrically-conducting shell (20) surrounding said sleeve, and a second electrode (22) mounted on said shell. The electrodes (16 and 22) define a spark gap (G1) of the plug. The shell (20) has an end portion (20c) terminating at an end surface (20b) of the shell. The sleeve (12) extends past said end portion (20c) with a clearance therebetween and extends beyond said end surface (20b). The sleeve (12) has at least one projection (32) which projects from the sleeve (12) and reduces said clearance in the region of the end surface (20b), thereby forming a secondary spark gap (G2).

Abstract: A fuel injector (10; 100) comprises an inlet (60) from which fuel can be transferred into a cavity (61) of the injector, at least one outlet orifice (86) communicating with said cavity (61), and ejecting means (44, 88) operable to apply force to fuel in said cavity to cause said fuel to be ejected through said orifice as discreet charges at pre-determined intervals. The operation of said ejecting means (44, 88) is also operable to transfer further fuel into said cavity (61).

Abstract: A spark plug comprises an electrically-insulating sleeve (12) extending along a central axis (14) of the plug, a first electrode (16) having a tip (20), an electrically-conducting shell (22), and a second electrode (26) mounted on the shell, the second electrode having a tip (28). The tips (20 and 28) have spark surfaces (30, 32) which define a spark gap (34) of the plug. The spark surfaces (30, 32) are inclined at different angles (&thgr;1, &thgr;2) relative to a plane (36, 38) extending normally of said central axis (14) of the plug so that said spark gap (34) varies in width along the length of the gap with the narrowest point (X1) of the gap being further from the connection between the second electrode (26) and the shell (22) than the other end of the gap.

Abstract: A fuel injector (10; 100) comprises an inlet (60) from which fuel can be transferred into a cavity (61) of the injector, at least one outlet orifice (86) communicating with said cavity (61), and ejecting means (44, 88) operable to apply force to fuel in said cavity to cause said fuel to be ejected through said orifice as discreet charges at pre-determined intervals. The operation of said ejecting means (44, 88) is also operable to transfer further fuel into said cavity (61).

Abstract: A spark plug (30; 40) comprises an electrically-insulating sleeve (12), a first electrode (16), an electrically-conducting shell (20) surrounding said sleeve, and a second electrode (22) mounted on said shell. The electrodes (16 and 22) define a spark gap (G1) of the plug. The shell (20) has an end portion (20c) terminating at an end surface (20b) of the shell. The sleeve (12) extends past said end portion (20c) with a clearance therebetween and extends beyond said end surface (20b). The sleeve (12) has at least one projection (32) which projects from the sleeve (12) and reduces said clearance in the region of the end surface (20b), thereby forming a secondary spark gap (G2).