A pump apparatus includes: a rotational shaft; a hub portion mounted to the rotational shaft; a centrifugal pump vane mounted to a circumferential surface of the hub portion; an annular disc portion mounted to a tip end of the centrifugal pump vane; and an axial turbine blade mounted to an outer circumferential surface of the annular disc portion. A liquid flow passage through which a liquid flowing from a first side toward a second side in an axis direction of the rotational shaft flows into the centrifugal pump vane is formed at a radially inner side of the annular disc portion, and a gas flow passage through which a gas flowing from the second side toward the first side passes through the axial turbine blade is formed at a radially outer side of the annular disc portion.

A pump apparatus includes: a rotational shaft; a hub portion mounted to the rotational shaft; a centrifugal pump vane mounted to a circumferential surface of the hub portion; an annular disc portion mounted to a tip end of the centrifugal pump vane; and an axial turbine blade mounted to an outer circumferential surface of the annular disc portion. A liquid flow passage through which a liquid flowing from a first side toward a second side in an axis direction of the rotational shaft flows into the centrifugal pump vane is formed at a radially inner side of the annular disc portion, and a gas flow passage through which a gas flowing from the second side toward the first side passes through the axial turbine blade is formed at a radially outer side of the annular disc portion.

A conduit engaging mechanism has a first member and a second member. The first member and the second member define and form fuel passages extending over them. A seal member is disposed between the first member and the second member. The first member and the second member are firmly engaged in a radial direction by fittingly coupling an engaging section and a fitting section. The first member and the second member are engaged by an engaging mechanism in an axial direction. The fuel passages are communicated as a series of passages by engaging the first passage forming section and the second passage forming section. The first passage forming section has a flexible pipe. The flexible pipe suppresses extension and contraction of the seal member by deflection itself. Consequently, deterioration of the seal member is suppressed.

A conduit engaging mechanism has a first member and a second member. The first member and the second member define and form fuel passages extending over them. A seal member is disposed between the first member and the second member. The first member and the second member are firmly engaged in a radial direction by fittingly coupling an engaging section and a fitting section. The first member and the second member are engaged by an engaging mechanism in an axial direction. The fuel passages are communicated as a series of passages by engaging the first passage forming section and the second passage forming section. The first passage forming section has a flexible pipe. The flexible pipe suppresses extension and contraction of the seal member by deflection itself. Consequently, deterioration of the seal member is suppressed.

A fuel supply device for supplying fuel into a combustion chamber of an internal combustion engine is provided. The device includes: a low pressure fuel supply pipe to which a low pressure fuel is supplied; a high pressure fuel supply pipe to which high pressure fuel to be supplied into the combustion chamber is supplied; fuel supply units provided between the low pressure fuel supply pipe and the high pressure fuel supply pipe, each of the fuel supply units being configured to boost the fuel in the low pressure fuel supply pipe and supply the boosted fuel to the high pressure fuel supply pipe; and a control unit configured to control the fuel supply units. The control unit controls the fuel supply units such that a total amount of ejection of the fuel ejected from the fuel supply units per unit time is close to a constant value.

A fuel supply device for supplying fuel into a combustion chamber of an internal combustion engine is provided. The device includes: a low pressure fuel supply pipe to which a low pressure fuel is supplied; a high pressure fuel supply pipe to which high pressure fuel to be supplied into the combustion chamber is supplied; fuel supply units provided between the low pressure fuel supply pipe and the high pressure fuel supply pipe, each of the fuel supply units being configured to boost the fuel in the low pressure fuel supply pipe and supply the boosted fuel to the high pressure fuel supply pipe; and a control unit configured to control the fuel supply units. The control unit controls the fuel supply units such that a total amount of ejection of the fuel ejected from the fuel supply units per unit time is close to a constant value.

A fuel supply device includes a fuel pump, a filter case, a fuel passage, a discharge passage, and a residual pressure holding valve. A communication port opens at a shifted position of the fuel passage that is positionally shifted from the residual pressure holding valve toward the discharge passage. The fuel passage includes an outside passage part through which fuel flows from the communication port toward the discharge passage, and an inside passage part that throttles a flow of fuel flowing from the communication port toward the residual pressure holding valve more than the outside passage part. When a passage cross-sectional area of the inside passage part is converted into a passage cross-sectional area of a circular pipe, D which is a passage diameter of the circular pipe, and L which is a length of the inside passage part satisfy a relational expression of L/D3.

A fuel supply device includes a fuel pump, a filter case, a fuel passage, a discharge passage, and a residual pressure holding valve. A communication port opens at a shifted position of the fuel passage that is positionally shifted from the residual pressure holding valve toward the discharge passage. The fuel passage includes an outside passage part through which fuel flows from the communication port toward the discharge passage, and an inside passage part that throttles a flow of fuel flowing from the communication port toward the residual pressure holding valve more than the outside passage part. When a passage cross-sectional area of the inside passage part is converted into a passage cross-sectional area of a circular pipe, D which is a passage diameter of the circular pipe, and L which is a length of the inside passage part satisfy a relational expression of L/D3.

A fuel supply device includes a fuel pump and a filter case that houses a fuel filter, a fuel pumped by the fuel pump from inside a fuel tank is filtered by the fuel filter and supplied from inside the filter case toward an internal combustion engine, and the filter case includes a case body having a closed bottom shape that forms a housing chamber of the fuel filter, a case cap that covers an aperture of the case body by being joined to the case body, and a residual pressure retention valve that, when the fuel pump is stopped, retains a pressure of the fuel supplied from inside the filter case toward the internal combustion engine, the residual pressure retention valve being disposed at a joint boundary of the case body and the case cap.

A fuel supply device includes: a linear actuator; a reciprocating pump having a boosting piston driven by the linear actuator, configured to axially reciprocate, and configured to alternately repeat suction of the fuel and ejection of the fuel more boosted than the fuel at a time of suction by reciprocation of the boosting piston; and a controller to control driving of the linear actuator. When reciprocation amplitude of the boosting piston is A (A>0) and a reciprocating cycle time is T, the controller controls the linear actuator so a maximum value of an absolute value of acceleration when the reciprocating pump sucks the fuel with an absolute value of speed of the boosting piston increasing is smaller than A.Math.(2/T).sup.2, and so a maximum value of the absolute value of the acceleration of the boosting piston when the reciprocating pump ejects the fuel is larger than A.Math.(2/T).sup.2.