Denso Corporation

Shinsuke Yamamoto

Kouichi Mochizuki

Eiji Itoh

Tomoji Matsukawa

Shinobu Oikawa

Moriyasu Gotoh

Atsuya Okamoto

Koichi Sugiyama

Yuki Watanabe

Kingo Okada

Takayuki Hokao

Masaki Akutagawa

Eiji Mimura

Haruki Suzuki

Tohru Sekido

A fixed core generates a magnetic attraction force with energization of a coil. A movable core has an attracted surface facing an attracting surface of the fixed core is attracted to the fixed core to cause the valve body to open a nozzle hole. A stopper member abuts against the movable core to restrict movement of the movable core. The movable core has an abutment portion that abuts against the stopper member, and a core body portion in which the attracted surface is formed. The attracting surface and the attracted surface extend annularly around an axis line of the fixed core, are formed so as to be separated from each other in an axis line direction in a state where the abutment portion abuts against the stopper member, and a separation distance from each other increases toward a radially outer side.

Fuel injection valve

A fuel injection valve includes a valve body, a fixed core, a movable core, a holder, and a stopper. The movable core has an inner core that contacts the stopper, and an outer core press-fitted to an outer peripheral surface of the inner core. The outer core has, in a moving direction of the movable core, a press-fit region which is press-fitted to the outer peripheral surface of the inner core, and a non-press-fit region which is not press-fitted to the outer peripheral surface of the inner core and is adjacent to the press-fit region in the moving direction. Between the inner peripheral surface of the holder and the outer peripheral surface of the movable core, the smallest gap in the press-fit region is larger than the smallest gap in the non-press-fit region.

A fuel injection valve includes a valve body, a fixed core, a movable core, a spring and a cup. The movable core has a first core contact surface which contacts the valve body when the movable core is moved by a predetermined distance away from a nozzle hole, and a second core contact surface which contacts the cup when the movable core is moved away from the nozzle hole. The movable core, the cup and the valve body form a fuel storage chamber which is surrounded by the movable core, the cup and the valve body to accumulate fuel. The first core contact surface is located inside the fuel storage chamber. The first core contact surface and the second core contact surface have a communication groove through which the inside and the outside of the fuel storage chamber communicate with each other.

A fuel injection valve includes a valve body, a fixed core, a movable core, a spring, and a cup. The spring is elastically deformed according to valve opening operation of the valve body, and exerts a valve closing elastic force for closing the valve body. The cup contacts a valve closing contact surface of the valve body, and transmits the valve closing elastic force to the valve body. At a start of predetermined-distance movement of the movable core together with the cup, the cup is in contact with the valve closing contact surface, and the valve body or the cup has a supply flow channel through which fuel is supplied to the valve body closing contact surface which is in a state contacting the cup.

A fuel injection valve includes a valve body, a fixed core, a movable core, a spring, a cup, and a guide. The cup contacts the spring and the valve body to transmit a valve closing elastic force to the valve body, and includes a cylindrical portion having a cylindrical shape. The guide has a sliding surface on which an outer peripheral surface of the cylindrical portion slides so as to guide the movement of the cylindrical portion in an axial direction while restricting the movement of the cylindrical portion in a radial direction. The guide has a recessed surface connected to the sliding surface and recessed to increase a gap between the recessed surface and the cup in the radial direction.

A fuel injection valve includes: a housing that includes an injection hole and a valve seat; a needle that includes a flange at a radially outer side of the needle and opens or closes the injection hole; a movable core that is installed on the valve seat side of the flange; a first spring that urges the needle toward the valve seat side; a second spring that urges the movable core toward an opposite side, which is opposite from the valve seat; and a limiting member that is installed on a radially outer side of the needle such that the limiting member enables movement of the movable core between the limiting member and the flange on the valve seat side of the flange. The limiting member includes an outside projection, which supports the second spring; and a tubular portion and an inside projection, which are contactable with the movable core.

A fuel injection valve includes: a circular plate portion that is abuttable against an end surface of a needle opposite from a valve seat while the needle being provided to open and close an injection hole upon lifting and seating of the needle relative to the valve seat; and a tubular portion that extends from the circular plate portion toward the valve seat and has an end part, which is opposite from the circular plate portion and is abuttable against a movable core second contact surface of a movable core opposite from the valve seat. In a state where the circular plate portion abuts against the needle, and the tubular portion abuts against the movable core, a gap is formed between a flange member end surface of a flange of the needle and a movable core first contact surface of the movable core opposite from the valve seat.

A gap forming member has: a plate portion that is placed on an opposite side of a needle, which is opposite from a valve seat; and an extending portion that is formed to extend from the plate portion toward the valve seat, while an opposite end part of the extending portion, which is opposite from the plate portion, is contactable with a movable core. A first wall surface of the gap forming member, which is a wall surface opposed to an outer wall of the flange, is slidable relative to the outer wall of the flange, and a second wall surface of the gap forming member, which is a wall surface opposed to an inner wall of a stationary core, forms a radial gap, which is a gap in a radial direction, between the second wall surface and the inner wall of the stationary core.

Fuel injection device

An inner side wall surface of a gap forming member, which is opposed to a flange outer wall surface of a flange of a needle, is slidable relative to the flange outer wall surface. Also, an outer side wall surface of the gap forming member, which is opposed to a stationary core inner wall surface of a stationary core, is slidable relative to the stationary core inner wall surface. The flange outer wall surface and the outer side wall surface are curved to project in a radially outer direction of a housing in a cross section thereof taken along an imaginary plane, which includes an axis of the housing.

A current control unit in a fuel injection device controls a magnitude of a current flowing through a coil during single energization. A current Ipflows once a signal input to the current control unit is turned ON at time t. As a result, a movable core and a needle abut against each other with a lift amount increased at time t, and then the needle is separated from a valve seat and pre-injection is performed. At time t, which follows the pre-injection, the needle and movable core lift amount becomes a lift amount Dat a time when the needle and the valve seat abut against each other, and temporary valve closing occurs. At time t, which follows time t, currents Ixand Imlarger than the current Ipare caused to flow through the coil, and then main injection is performed with the needle and movable core lift amount turned into a lift amount Dlarger than the lift amount D. Therefore, fuel injection can be performed twice during the single energization.

A movable core is movable relative to a needle main body of a needle. A stationary core is placed on an opposite side of the movable core, which is opposite from a valve seat. A spring is operable to urge the needle and the movable core toward the valve seat. A spring seat is shaped into a ring form and is placed on a radially outer side of the needle main body at the valve seat side of the movable core. The spring is placed between the movable core and the spring seat and is operable to urge the movable core toward the stationary core. A guide is placed on the valve seat side of the movable core in an inside of a housing. An outer wall of the spring seat is slidable relative to an inner wall of the guide to guide reciprocation of the needle.

A fuel injection valve includes a housing having a nozzle hole, a valve seat, and a fuel passage; a needle that is accommodated in the housing to be capable of reciprocating in an axial direction of the housing and that opens or closes the nozzle hole; a coil; a fixed core; a movable core; a shift permitting member that is provided between the housing and an internal-combustion engine to permit a shift of an attachment position at time of attachment of the housing and the engine; and a friction reducing part that is provided between the engine and the shift permitting member to reduce friction between the engine and the shift permitting member. The friction reducing part permits displacement of the housing in a direction perpendicular to the axial direction of the housing.

Growing community of inventors

Kariya, Japan

Shinsuke Yamamoto