High-pressure pump
A fuel gallery has an inlet opening through which a fuel is introduced therein and a suction opening through which the fuel flows between the fuel gallery and a compression chamber. A pulsation damper is supported in the fuel gallery by a first and a second supporting member. The second supporting member defines an inner fuel chamber and outer fuel chamber which communicates with each other through apertures. The suction opening is located at a side wall of the fuel gallery and the inlet opening is located at a bottom wall of the inner fuel chamber which is defined radially inside of the second supporting member. The fuel discharged into the outer fuel chamber through the suction opening is introduced into the inner fuel chamber through the apertures. A flow velocity of the fuel is decreased and a pressure pulsation reduction effect of the pulsation damper is surely achieved.
1. A high-pressure pump comprising:
a housing defining a compression chamber and a fuel gallery therein, the compression chamber having a discharge port through which a fuel is discharged therefrom, the fuel gallery having an inlet opening through which the fuel flows thereinto, the fuel gallery having a suction opening communicating with the compression chamber;
a plunger slidably arranged in the compression chamber and varying a volume of the compression chamber in order to suction the fuel into the compression chamber or to discharge the fuel from the compression chamber;
a suction valve provided in a fuel suction passage fluidly connecting the compression chamber and the fuel gallery, the suction valve discharging a part of the fuel in the compression chamber into the fuel gallery through the suction opening to adjust a quantity of fuel which is discharged from the discharge port when the plunger slides up to reduce the volume of the compression chamber;
a damper provided in the fuel gallery for attenuating a pressure pulsation of the fuel in the fuel gallery, the damper comprised of a first diaphragm and a second diaphragm which respectively have a first peripheral edge portion and a second peripheral edge portion, the first peripheral edge portion and the second peripheral edge portion being joined together in order to form a damper chamber in the damper;
an annular first supporting member supporting the first peripheral edge portion of the first diaphragm, the first supporting member defining a first inner fuel chamber radially inside; and
an annular second supporting member supporting the second peripheral edge portion of the second diaphragm, the annular second supporting member defining a second inner fuel chamber radially inside,
wherein:
the first supporting member and the second supporting member define an outer fuel chamber radially outside thereof,
the second inner fuel chamber and the outer fuel chamber communicate with each other through a restriction,
one of the inlet opening and the suction opening is located to confront the outer fuel chamber, and
the other of the inlet opening and the suction opening is located to confront the second inner fuel chamber,
the restriction is a plurality of apertures which penetrates the second supporting member to communicate the outer fuel chamber with the second inner fuel chamber,
the apertures are arranged circumferentially along the annular second supporting member, and
an opening area of the apertures is smaller than that of the suction opening so that a flow velocity of the fuel flowing into the second inner fuel chamber from the outer fuel chamber is decreased by the apertures when flowing through the apertures, and
wherein:
the plunger includes a large diameter portion, and a small diameter portion, and a plunger surrounding portion which defines a variable volume chamber around the small diameter portion,
in a case that the volume of the compression chamber is decreased, a volume of the variable volume chamber is increased so that the fuel is introduced into the variable volume chamber from the fuel gallery through a variable volume chamber passage,
in a case that the volume of the compression chamber is increased, the volume of the variable volume chamber is decreased so that the fuel is introduced into the fuel gallery from the variable volume chamber fuel gallery through the variable volume chamber passage, and
a volume chamber opening of the variable volume chamber passage opens at the fuel gallery radially outside of the second supporting member.
2. A high-pressure pump according to claim 1 , wherein
the outer fuel chamber is defined radially outside of the first supporting member and the second supporting member along an entire axis line thereof.
3. A high-pressure pump according to claim 1 , wherein
the outer fuel chamber is defined along an entire circumferential outer surface of the first supporting member and the second supporting member.
4. A high-pressure pump according to claim 1 , wherein
the first inner fuel chamber communicates with the outer fuel chamber.
5. A high-pressure pump according to claim 1 , wherein
the suction opening is located radially outside of the second supporting member, and
the fuel suction passage fluidly connecting the suction opening and the compression chamber is formed in such a manner that the fuel discharged from the suction opening into the outer fuel chamber flows in a direction toward the first supporting member or the damper which biases the first supporting member to the first peripheral edge portion of the first diaphragm.