Abstract: A valve mechanism includes a valve (a butterfly valve 30) arranged in a path in which gas flows, a drive shaft (32) coupled to the valve, and a lever member (33) attached to a lever attachment portion (321) provided at the drive shaft. The lever attachment portion of the drive shaft has a non-circular cross-sectional shape. The lever member has a through-hole (331) in a shape corresponding to a non-circular cross section of the lever attachment portion, and is fitted onto the lever attachment portion. The lever member is fixed to the drive shaft in such a manner that a first contact portion (a first contact member 34) and a second contact portion (323) sandwich the lever member in an axial direction of the drive shaft.

Abstract: An exhaust passage 53 includes: a first passage (high-speed passages 24b, 25b, and 26b); and a second passage (low-speed passages 24c, 25c, and 26c). A turbine housing 560 is connected to the exhaust passage 53 downstream from the collector 54. An exhaust device 100 of an engine 1 includes a valve (an exhaust variable valve 3) to open and close the first passage. A controller (an engine controller 7) closes the valve if an engine speed of the engine 1 is lower than a predetermined engine speed and opens the valve if the engine speed of the engine 1 is higher than or equal to the predetermined engine speed. The controller opens the valve even though the engine speed of the engine 1 is lower than the predetermined engine speed if performing the fuel cut control.

Abstract: A negative pressure type actuator (4) includes a diaphragm (43), an output shaft (44) extending toward an opposite side of a negative pressure chamber (410), a stopper (46) provided such that the output shaft penetrates the stopper, and a stopper engagement portion (47) fixed to the output shaft. The stopper has a first contact surface (462) configured to contact a stopper engagement portion, and the stopper engagement portion has a second contact surface (471). The first contact surface (462) is formed in an arc shape in a section including the axis (X2) of the output shaft, and the second contact surface (471) is, in the section including the axis of the output shaft, formed in an arc shape with the same curvature as that of the first contact surface.

Abstract: An exhaust passage 53 includes: a first passage (high-speed passages 24b, 25b, and 26b); and a second passage (low-speed passages 24c, 25c, and 26c). A turbine housing 560 is connected to the exhaust passage 53 downstream from the collector 54. An exhaust device 100 of an engine 1 includes a valve (an exhaust variable valve 3) to open and close the first passage. A controller (an engine controller 7) closes the valve if an engine speed of the engine 1 is lower than a predetermined engine speed and opens the valve if the engine speed of the engine 1 is higher than or equal to the predetermined engine speed. The controller opens the valve even though the engine speed of the engine 1 is lower than the predetermined engine speed if performing the fuel cut control.

Abstract: An exhaust system of an engine includes a plate-like valve configured to change a cross-sectional area of an exhaust passage, a drive shaft configured to rotate the valve, a bearing provided for a wall member segmenting the exhaust passage to rotatably support the valve, and a driver configured to rotate the drive shaft. The drive shaft penetrates the wall member, and includes an extension extending outside the exhaust passage. The system also includes an auxiliary bearing that rotatably supports the extension of the drive shaft. The auxiliary bearing is spaced apart from the wall member by a predetermined distance.

Abstract: Disclosed is an exhaust gas recirculation system provided in an engine to recirculate, to an intake manifold, a part of exhaust gas discharged from an engine body, as EGR gas. The exhaust gas recirculation system comprises: an in-head gas passage formed in a cylinder head to allow the EGR gas to pass through a position adjacent to a first coolant jacket formed in the cylinder head to allow coolant to flow therethrough an EGR cooler configured to cool the EGR gas after passing through the cylinder head via the in-head gas passage and before being introduced into the intake manifold; and a relay pipe configured to guide the EGR gas just after passing through the cylinder head, to the EGR cooler. The relay pipe is provided with a second coolant jacket for allowing coolant to flow therethrough so as to cool the EGR gas being flowing inside the relay pipe.