An internal combustion engine (1) including a fuel reformation cylinder (2) for reforming a fuel and an output cylinder (3) for yielding an engine power by combusting a fuel or a reformed fuel, wherein at least a part of the surfaces constituting a volume-variable reaction chamber (23) of the fuel reformation cylinder (2) has a highly heat-insulative material (10).

When an amount of a backward tumble flow is smaller than an amount of a forward tumble flow, the intake-side valve recess is used as a first valve recess and the exhaust-side valve recess is used as a second valve recess. When the amount of the backward tumble flow is larger than the amount of the forward tumble flow, the exhaust-side valve recess is used as a first valve recess and the intake-side valve recess is used as a second valve recess. An inclination angle of the first valve recess is larger than an inclination angle of the second valve recess when comparing the inclination angle such that a height of the recess decreases gradually toward an inner side of a cross-section.

Provided is an in-combustion chamber flow control device used in an engine having an intake passage connected to an intake opening formed in a ceiling surface of a combustion chamber, at an angle inclined with respect to a direction of an axis of a cylinder. This in-combustion chamber flow control device comprises a plasma actuator (28) disposed inside the combustion chamber (16). The plasma actuator comprises: a dielectric body (38) disposed along the ceiling surface (16a) of the combustion chamber, at a position closer to a center of the ceiling surface than the intake opening (18a); an exposed electrode (40) disposed on one side of the dielectric body facing the combustion chamber; and an embedded electrode (42) disposed on a side opposite to the exposed electrode across the dielectric body. The embedded electrode is disposed at a position closer to the intake opening than the exposed electrode.

Provided is an in-combustion chamber flow control device used in an engine having an intake passage connected to an intake opening formed in a ceiling surface of a combustion chamber, at an angle inclined with respect to a direction of an axis of a cylinder. This in-combustion chamber flow control device comprises a plasma actuator (28) disposed inside the combustion chamber (16). The plasma actuator comprises: a dielectric body (38) disposed along the ceiling surface (16a) of the combustion chamber, at a position closer to a center of the ceiling surface than the intake opening (18a); an exposed electrode (40) disposed on one side of the dielectric body facing the combustion chamber; and an embedded electrode (42) disposed on a side opposite to the exposed electrode across the dielectric body. The embedded electrode is disposed at a position closer to the intake opening than the exposed electrode.

The present invention relates to an internal-combustion engine comprising a combustion chamber provided with a single intake valve (2), a single exhaust valve (3), two plugs (4a, 4b) and a fuel injector (5). Furthermore, the combustion chamber comprises means for forming an aerodynamic swirling motion structure of the intake gas in the combustion chamber. Besides, fuel injector (5) is oriented so as to inject the fuel into the central area of the combustion chamber in the direction of the aerodynamic swirling motion structure.

An internal combustion engine includes an intake port configured to generate a swirl in a cylinder, an exhaust port, and a piston. The piston includes a top surface provided in an upper portion of the piston, a cavity provided from the top surface toward a lower portion of the piston around a central axis of the piston, and a connection surface connecting an inner edge of the top surface and an upper end of a side surface of the cavity to each other. The connection surface is provided to be closer to a lower portion side of the piston than the top surface. An area of the connection surface projected on a plane parallel to the top surface is larger on an intake port side than on an exhaust port side.

An internal combustion engine includes an intake port configured to generate a swirl in a cylinder, an exhaust port, and a piston. The piston includes a top surface provided in an upper portion of the piston, a cavity provided from the top surface toward a lower portion of the piston around a central axis of the piston, and a connection surface connecting an inner edge of the top surface and an upper end of a side surface of the cavity to each other. The connection surface is provided to be closer to a lower portion side of the piston than the top surface. An area of the connection surface projected on a plane parallel to the top surface is larger on an intake port side than on an exhaust port side.

An engine includes: a turbocharger including a turbine and a compressor; an EGR passage connecting an exhaust passage on an upstream side of the turbine and an air intake passage on a downstream side of the compressor; an EGR valve provided in the EGR passage; a bypass passage that bypasses the turbine; and a waste gate valve provided in the bypass passage. In the engine, when a boost pressure is increased to a limit pressure, a first boost pressure control is executed, in which the EGR valve is opened and the waste gate valve is closed. After the first boost pressure control starts, when an engine speed is increased to a prescribed value, a second boost pressure control is executed, in which the waste gate valve is opened in addition to the EGR valve.

An engine includes: a turbocharger including a turbine and a compressor; an EGR passage connecting an exhaust passage on an upstream side of the turbine and an air intake passage on a downstream side of the compressor; an EGR valve provided in the EGR passage; a bypass passage that bypasses the turbine; and a waste gate valve provided in the bypass passage. In the engine, when a boost pressure is increased to a limit pressure, a first boost pressure control is executed, in which the EGR valve is opened and the waste gate valve is closed. After the first boost pressure control starts, when an engine speed is increased to a prescribed value, a second boost pressure control is executed, in which the waste gate valve is opened in addition to the EGR valve.

In an internal combustion engine, an angle defined by an axis of a boundary of an intake port adjoining a valve seat and a cylinder axis is greater than an angle defined by the axis of the valve seat and the cylinder axis. A step between a first inner wall and a second inner wall, the first inner wall being a portion of an inner wall of the valve seat that is closest to the cylinder axis and the second inner wall being a portion of an inner wall of the boundary of the intake port that is closest to the cylinder axis. The first inner wall is located on the outer side in the radial direction of the intake port than the second inner wall.