An opening/closing valve structure for an engine is provided with a valve body for opening and closing an intake passage or an exhaust passage of the engine; a pair of bush members mounted on axial ends of the valve body; and a shaft member axially passing through one of the bush members and projecting from the bush member by a predetermined length within one end of the valve body. Each of the bush members is mounted in such a manner that a part of the bush member is axially received in an end of the valve body and the remaining part thereof axially projects from the end of the valve body. A portion of the shaft member projecting from the one of the bush members is connected to the valve body in such a manner that relative rotation of the shaft member with respect to the valve body is disabled.

An opening/closing valve structure for an engine is provided with a valve body for opening and closing an intake passage or an exhaust passage of the engine; a pair of bush members mounted on axial ends of the valve body; and a shaft member axially passing through one of the bush members and projecting from the bush member by a predetermined length within one end of the valve body. Each of the bush members is mounted in such a manner that a part of the bush member is axially received in an end of the valve body and the remaining part thereof axially projects from the end of the valve body. A portion of the shaft member projecting from the one of the bush members is connected to the valve body in such a manner that relative rotation of the shaft member with respect to the valve body is disabled.

An air intake device for an internal combustion engine of the present invention includes a water discharge passage extending from a bottom surface of a control valve housing part recessed in a housing passage forming part of an air intake passage to an air intake port. The water discharge passage is formed independently from the air intake passage, and includes: a water collection groove recessed in the bottom surface; a water discharge hole formed penetrating a cover of a valve control housing; and a water discharge hole penetrating a flange part of an insert inserted into the air intake port. The downstream end of the water discharge hole is connected to a space defined between an air intake port inner wall surface and an insert cylindrical part.

An air intake device for an internal combustion engine of the present invention includes a water discharge passage extending from a bottom surface of a control valve housing part recessed in a housing passage forming part of an air intake passage to an air intake port. The water discharge passage is formed independently from the air intake passage, and includes: a water collection groove recessed in the bottom surface; a water discharge hole formed penetrating a cover of a valve control housing; and a water discharge hole penetrating a flange part of an insert inserted into the air intake port. The downstream end of the water discharge hole is connected to a space defined between an air intake port inner wall surface and an insert cylindrical part.

An air intake device includes: a valve body which includes a rotating shaft; a bearing member which rotatably supports the rotating shaft of the valve body; and an air intake port which includes a concave portion on which the bearing member is disposed, wherein the bearing member includes a positioning portion for positioning the bearing member with respect to the concave portion of the air intake port, facing surfaces which extend from the positioning portion along the concave portion of the air intake port and face each other in an inward radial direction of the rotating shaft with respect to the concave portion, with a gap therebetween, and protruding portions which protrude toward the concave portion of the air intake port from the facing surfaces and seal the gap.

An air intake device includes: a valve body which includes a rotating shaft; a bearing member which rotatably supports the rotating shaft of the valve body; and an air intake port which includes a concave portion on which the bearing member is disposed, wherein the bearing member includes a positioning portion for positioning the bearing member with respect to the concave portion of the air intake port, facing surfaces which extend from the positioning portion along the concave portion of the air intake port and face each other in an inward radial direction of the rotating shaft with respect to the concave portion, with a gap therebetween, and protruding portions which protrude toward the concave portion of the air intake port from the facing surfaces and seal the gap.

A control system for a compression-ignition engine is provided, which includes an engine having a combustion chamber, an injector configured to supply fuel into the combustion chamber, a spark plug, a swirl valve provided to an intake passage of the engine, and a controller connected to the injector, the spark plug and the swirl valve to control them. The controller includes a processor configured to execute a swirl adjusting module to adjust an opening of the swirl valve to generate a swirl flow inside the combustion chamber, a fuel injection timing controlling module to control a fuel injection timing and control the injector to retard the fuel injection timing as an engine speed increases, and a combustion controlling module to control the spark plug to ignite at a given ignition timing after the swirl generation and the fuel injection, so that partial compression-ignition combustion is performed.

A control system for a compression-ignition engine is provided, which includes an engine having a combustion chamber, an injector, a spark plug, a swirl valve provided to an intake passage of the engine, and a controller connected to the injector, the spark plug, and the swirl valve to control them. The controller includes a processor configured to execute a swirl adjusting module to control an opening of the swirl valve so as to make the opening of the swirl valve smaller as an engine speed decreases and output a control signal to the injector to inject the fuel after the control of the swirl valve, and a combustion controlling module to output an ignition instruction to the spark plug so as to ignite at a given ignition timing after the EGR ratio adjustment, so that partial compression-ignition combustion is performed.

A cylinder head for an internal combustion engine including a cylinder head arrangement having an intake port, an injector connected to the cylinder head arrangement, and a tubular injection tube extending along a tube core axis into the intake port and fluidly connected to the injector, an attachment element being arranged on the injection tube, and the attachment element having an air guiding portion which extends radially outwards with respect to the tube core axis in such a way that a flow in the intake port is influenced by the air guiding portion.

A cylinder head for an internal combustion engine including a cylinder head arrangement having an intake port, an injector connected to the cylinder head arrangement, and a tubular injection tube extending along a tube core axis into the intake port and fluidly connected to the injector, an attachment element being arranged on the injection tube, and the attachment element having an air guiding portion which extends radially outwards with respect to the tube core axis in such a way that a flow in the intake port is influenced by the air guiding portion.