Abstract: A fuel cell system includes a fuel cell that discharges hydrogen off-gas including an unreacted portion of the hydrogen gas together with nitrogen gas and moisture, a hydrogen supply passage; a return passage to return the hydrogen off-gas to the hydrogen supply passage, a gas-liquid separator that is provided on the return passage, obtains dehumidified hydrogen gas by separating the moisture from the hydrogen off-gas, an exhaust valve to discharge the dehumidified hydrogen gas from the return passage, a pressure sensor to detect pressure in the return passage, and a control device that controls the exhaust valve. The control device estimates a concentration of the nitrogen gas included in the dehumidified hydrogen gas based on a detection value of the pressure sensor, and controls the exhaust valve to open when the concentration of the nitrogen gas becomes not less than a predetermined value.

Abstract: A separator for a fuel cell includes a rectangular plate-shaped body. The body forms passages through which gas flows. The body includes central regions and a reversing region. The central regions extend along one side of the body, and are arranged in a direction in which another side of the body that intersects the one side extends. The passages include multiple central passage sections that extend in the longitudinal direction through each central region, and a reversing passage section that extends through the reversing region and connects the central passage sections of adjacent ones of the central regions. The ribs are formed such that two or more of the central passage sections are formed in each of the central regions, and the reversing passage section in the reversing region is connected to two or more of the central passage sections in the corresponding central region.

Abstract: A fuel cell stack includes multiple stacked single cells. Each single cell includes a power generation portion, a first separator, and a second separator. Each single cell includes a cooling medium supplying hole at an end portion on one side in a first direction and a cooling medium discharging hole at an end portion on the other side in the first direction. The first separator includes grooves and ridges that form multiple meandering first passages. The second separator includes grooves and ridges that form multiple meandering second passages. Reversing sections of the first passages and reversing sections of the second passages extend to be inclined with respect to a second direction. The reversing sections of the first passages and the reversing sections of the second passages overlap with each other so as to intersect with each other between the cooling medium supplying hole and the cooling medium discharging hole.

Abstract: A fuel cell stack includes stacked single cells. Each of the single cells includes a power generating unit and two separators that sandwich the power generating unit. A surface of each of the separators facing the power generating has gas passages and ribs that are alternately arranged. The ribs extend along the gas passages. Each of the gas passages includes at least one first extension and a second extension. At least one of the gas passages includes an island-shaped branching rib arranged in a curved portion. The branching rib branches the gas passage into branching passages. The branching passages include an outer passage and an inner passage.

Abstract: A fuel cell stack includes multiple stacked unit cells. Each unit cell includes a first separator, a second separator, and a power generation portion sandwiched by the first separator and the second separator. A flow passage and a gasket are arranged between the first separator of a first unit cell and the second separator of a second unit cell. The gasket surrounds a supply manifold, the flow passage, and a discharge manifold. The gasket includes an annular body and a guide projection. The first separator of the first unit cell includes at least one first rib located adjacent to an inner peripheral side of the body. The second separator of the second unit cell includes at least one second rib located adjacent to the inner peripheral side of the body. The first rib and the second rib project so as to contact each other and extend to intersect each other.

Abstract: A single cell for a fuel cell includes a power generating unit and two separators. Each separator includes a surface that faces the power generating unit, and includes gas passages. Each gas passage includes first extensions and a second extension. The second extension connects a downstream end of one of two adjacent first extensions and an upstream end of the other first extension to each other. A first rib is provided between adjacent ones of the first extensions. A second rib is provided on each first rib. The second rib of one of the two separators and the second rib of the other separator extend so as to intersect with each other when viewed in the direction in which the separators sandwich the power generating unit.

Abstract: A fuel cell stack includes stacked single cells. Each single cell includes a power generating unit, a frame including an accommodating hole, and two separators. Each separator has a surface facing the power generating unit. The surface has a gas passage. The gas passage includes first extensions and a second extension. A partition rib is provided between two of the first extensions connected to each other by the second extension. The partition rib includes a base that is in contact with a corresponding one of the gas diffusion layers of the power generating unit, and a protrusion that protrudes from the base into the corresponding gas diffusion layer. The protrusion has an opposing end opposed to an inner surface of the accommodating hole. A pressure loss increasing portion is provided at a boundary between the opposing end and the inner surface of the accommodating hole.

Abstract: A fuel cell stack includes stacked single cells. The single cells each include a power generation portion and a pair of a first separator and a second separator. The first separator includes first passages. The first passages each include first reversal portions and first general portions. The second separator includes second passages. The second passages each include second reversal portions and second general portions. The first reversal portions of the first passages each extend to increase a flow resistance of a cooling medium flowing through a part of a cooling medium flow region that corresponds to the first reversal portion. The second reversal portions of the second passages each extend to increase the flow resistance of the cooling medium flowing through a part of the cooling medium flow region that corresponds to the second reversal portion.

Abstract: A cover for an internal combustion engine is configured to be attached to an engine main body so as to cover a timing chain or a timing belt. The cover for the internal combustion engine includes insertion holes configured to receive a crankshaft or a camshaft. The cover for the internal combustion engine includes a first member made of a hard plastic and a second member made of a material different from the hard plastic. The first member is produced by insert molding with the second member embedded in the first member. A periphery of at least one of the insertion holes in the second member includes a joint surface that is joined to the first member. The joint surface includes annular grooves surrounding the insertion hole, the annular grooves being arranged in a radial direction of the insertion hole.

Abstract: A chain cover includes a first member, which is made of a hard plastic, and a second member, which is made of a material different from the hard plastic. The first member is formed by insert molding with the second member as an insert. A first joint surface is formed in a peripheral portion around an insertion hole. The first joint surface is joined to the first member. The first joint surface includes a first joint portion, which includes a lattice-shaped recess portion, and a second joint portion, which includes grooves. The grooves extend in a direction in which the peripheral portion extends, while being arranged in an intersecting direction, which intersects with the extending direction. The second joint portion is provided to be closer to a space adjacent to the peripheral portion than the first joint portion.

Abstract: A chain cover includes a first member, which is made of a hard plastic, and a second member, which is made of a material different from the hard plastic. The first member includes a back face, which faces an engine main body. The second member is joined to the first member. Only the back face of the first member includes a groove, which receives a seal member. The seal member provides a seal between the first member and the engine main body.

Abstract: A chain cover includes a first member, which is made of a hard plastic, and a second member, which is made of a material different from the hard plastic. The first member is formed by insert molding with the second member as an insert. A first joint surface is formed in a peripheral portion around an insertion hole. The first joint surface is joined to the first member. The first joint surface includes a first joint portion, which includes a lattice-shaped recess portion, and a second joint portion, which includes grooves. The grooves extend in a direction in which the peripheral portion extends, while being arranged in an intersecting direction, which intersects with the extending direction. The second joint portion is provided to be closer to a space adjacent to the peripheral portion than the first joint portion.

Abstract: A chain cover includes a first member, which is made of a hard plastic, and a second member, which is made of a material different from the hard plastic. The first member includes a back face, which faces an engine main body. The second member is joined to the first member. Only the back face of the first member includes a groove, which receives a seal member. The seal member provides a seal between the first member and the engine main body.

Abstract: A cover for an internal combustion engine is configured to be attached to an engine main body so as to cover a timing chain or a timing belt. The cover for the internal combustion engine includes insertion holes configured to receive a crankshaft or a camshaft. The cover for the internal combustion engine includes a first member made of a hard plastic and a second member made of a material different from the hard plastic. The first member is produced by insert molding with the second member embedded in the first member. A periphery of at least one of the insertion holes in the second member includes a joint surface that is joined to the first member. The joint surface includes annular grooves surrounding the insertion hole, the annular grooves being arranged in a radial direction of the insertion hole.

Abstract: A chain cover is configured to cover a timing chain that transmits rotation of a crankshaft of an internal combustion engine to a camshaft. The chain cover includes a crankshaft-side opening forming portion that defines a crankshaft-side opening into which the crankshaft is inserted, and a general portion that is a section different from the crankshaft-side opening forming portion. The crankshaft-side opening forming portion is made of a first material. The general portion is made of a second material. The first material and the second material are different from each other.

Abstract: An oil mist separator includes a case, an oil collecting portion, and a gradual change portion. The case includes a case main body, an inlet for blow-by gas provided on an upstream side of the case main body in a flowing direction of the blow-by gas, and an outlet for blow-by gas provided on a downstream side in the flowing direction of the case main body. The oil collecting portion is accommodated in the case main body. The gradual change portion is provided in the case and is located in at least one of a space between the inlet and the oil collecting portion in the flowing direction and a space between the oil collecting portion and the outlet in the flowing direction. A cross-sectional flow area of the gradual change portion is gradually decreased as a distance from the oil collecting portion in the flowing direction increases.

Abstract: A chain cover is configured to cover a timing chain that transmits rotation of a crankshaft of an internal combustion engine to a camshaft. The chain cover includes a crankshaft-side opening forming portion that defines a crankshaft-side opening into which the crankshaft is inserted, and a general portion that is a section different from the crankshaft-side opening forming portion. The crankshaft-side opening forming portion is made of a first material. The general portion is made of a second material. The first material and the second material are different from each other.

Abstract: An oil mist separator includes a case, an oil collecting portion, and a gradual change portion. The case includes a case main body, an inlet for blow-by gas provided on an upstream side of the case main body in a flowing direction of the blow-by gas, and an outlet for blow-by gas provided on a downstream side in the flowing direction of the case main body. The oil collecting portion is accommodated in the case main body. The gradual change portion is provided in the case and is located in at least one of a space between the inlet and the oil collecting portion in the flowing direction and a space between the oil collecting portion and the outlet in the flowing direction. A cross-sectional flow area of the gradual change portion is gradually decreased as a distance from the oil collecting portion in the flowing direction increases.