The cylinder head includes an intake port communicating with a cylinder of a cylinder block, a cylinder head main body having an exhaust port communicating with the cylinder, and a rocker housing integrally formed on the cylinder head main body and an inner side of which is defined as a valve-system accommodating space. The rocker housing includes a lateral wall having a lateral wall main body and a base end portion which extends along a lower end of the lateral wall main body, connects the lateral wall main body to the cylinder head main body, and has a thickness thicker than that of the lateral wall body. A flow path which extends in an extending direction of the base end portion and through which a fluid flow is formed in the base end portion.

An intake system for an internal combustion engine has at least one inlet channel through which air can flow and by which the air flowing through the inlet channel is to be conducted into at least one combustion chamber of the internal combustion engine. The inlet channel is, on the bottom side thereof, of flat form at least in one length region, wherein the flat bottom side extends as far as a tumble edge by which a tumbling flow of the air flowing into the combustion chamber can be effected.

An intake system for an internal combustion engine has at least one inlet channel through which air can flow and by which the air flowing through the inlet channel is to be conducted into at least one combustion chamber of the internal combustion engine. The inlet channel is, on the bottom side thereof, of flat form at least in one length region, wherein the flat bottom side extends as far as a tumble edge by which a tumbling flow of the air flowing into the combustion chamber can be effected.

An internal combustion engine includes: an intake control valve provided on an upstream side of a fuel injection device provided in an intake flow path and configured to adjust an opening degree thereof while maintaining an intake state through the intake flow path; and a controller configured to perform control to adjust the opening degree of the intake control valve, in which the controller is configured to set the intake control valve to a closing direction side such that a pressure between the intake control valve and an intake valve of a combustion chamber increases during a pre-ignition motor drive period until a fuel is supplied to the combustion chamber and first ignited.

An internal combustion engine includes: an intake control valve provided on an upstream side of a fuel injection device provided in an intake flow path and configured to adjust an opening degree thereof while maintaining an intake state through the intake flow path; and a controller configured to perform control to adjust the opening degree of the intake control valve, in which the controller is configured to set the intake control valve to a closing direction side such that a pressure between the intake control valve and an intake valve of a combustion chamber increases during a pre-ignition motor drive period until a fuel is supplied to the combustion chamber and first ignited.

An engine device having gas injectors attached to an intake manifold fixed to a side surface of a cylinder head. A fuel gas injected from the gas injectors is premixed in the intake manifold, and the resulting gas is supplied to a plurality of cylinders and ignited by ignition devices. The intake manifold has a configuration in which a plurality of intake branch pipes communicating with the cylinders are branched from an intake collecting pipe at an air supply side. The intake branch pipes include bent portions. In the bent portions of the intake branch pipes, inside inner walls near the cylinder head are bent at an acute angle.

Provided is a thermally insulated insert member and an engine having the thermally insulated insert member. Thermally insulated insert member is disposed in an intake port of a cylinder head of the engine. The thermally insulated insert member includes a guide member that guides a flow of intake air flowing in t he intake port; and a thermally insulative support member with a shape that can be fitted within the intake port. The guide member is formed of a metal and is supported in the intake port via the thermally insulative support member.

An intake device for an internal combustion engine, the intake device includes: a housing constituting an intake passage; a valve element including a valve portion arranged to open and close a part of the intake passage, and thereby to strengthen an intake air flow; and a receiving portion which is formed on a bottom wall of an aeration passage of the housing, and which is recessed in an arc shape along a movement trajectory of the valve portion, the valve portion including an outer side surface which confronts a bottom surface of the receiving portion, which has an arc shape, and which includes a seal portion that has a raised shape, and that extends along an edge portion on an upstream side of an intake direction.

An intake device for an internal combustion engine, the intake device includes: a housing constituting an intake passage; a valve element including a valve portion arranged to open and close a part of the intake passage, and thereby to strengthen an intake air flow; and a receiving portion which is formed on a bottom wall of an aeration passage of the housing, and which is recessed in an arc shape along a movement trajectory of the valve portion, the valve portion including an outer side surface which confronts a bottom surface of the receiving portion, which has an arc shape, and which includes a seal portion that has a raised shape, and that extends along an edge portion on an upstream side of an intake direction.

A compression ignited combustion engine has at least one cylinder and first and second gas intake ports in a cylinder head restricting a combustion chamber. One gas intake passage leads to the two ports and is widened in a Y-shaped end influencing gas entering each port into a tangential flow in opposite direction with respect to the flow into the other port. The first intake port is designed to allow gas entering this port to continue said tangential flow so as to enter the combustion chamber in a swirl in a first rotation direction, whereas the second intake port is designed to guide gas entering this port to also enter the combustion chamber in a swirl in said first rotation direction.