A uniflow engine includes a cylinder having a cylinder wall, an inlet channel, an extension of a central axis of the inlet channel first intersecting the cylinder wall in a first portion of the cylinder and next intersecting the cylinder wall in a second portion of the cylinder opposite the first portion of the cylinder, an intake air gallery, the intake air gallery having a gallery wall and being in flow communication with the inlet channel, and a plurality of intake ports extending between the cylinder wall and the gallery wall, at least some of the intake ports having different areas at the cylinder wall measured perpendicular to longitudinal axes of the intake ports, and wherein an area of at least one in take port in the first portion of the cylinder is larger than an area of at least one intake port in the second portion of the cylinder.

The invention relates to a two-stroke internal combustion engine, in particular for a motor vehicle, with direct fuel injection, comprising at least one working cylinder (1) which comprises a bushing and in which a piston (6) can be moved in an oscillating manner; at least one outlet channel (2) which opens into the working cylinder (1) above the upper dead center of the piston (6); at least two inlet openings (5) which are distributed over the circumference of the bushing and which open into the working cylinder (1) above the lower dead center of the piston (6) such that a uniflow scavenging process of the working cylinder (1) is produced during the operation of the two-stroke internal combustion engine; and a slider which releases and closes the inlet openings (5), whereby the slider is designed as a tube slider (4) which surrounds the bushing of the working cylinder (1) and which comprises a closed casing. The slider releases or closes the inlet openings (5) in an oscillating manner in the longitudinal direction of the bushing during the charge cycle.

The invention relates to a two-stroke internal combustion engine, in particular for a motor vehicle, with direct fuel injection, comprising at least one working cylinder (1) which comprises a bushing and in which a piston (6) can be moved in an oscillating manner; at least one outlet channel (2) which opens into the working cylinder (1) above the upper dead center of the piston (6); at least two inlet openings (5) which are distributed over the circumference of the bushing and which open into the working cylinder (1) above the lower dead center of the piston (6) such that a uniflow scavenging process of the working cylinder (1) is produced during the operation of the two-stroke internal combustion engine; and a slider which releases and closes the inlet openings (5), whereby the slider is designed as a tube slider (4) which surrounds the bushing of the working cylinder (1) and which comprises a closed casing. The slider releases or closes the inlet openings (5) in an oscillating manner in the longitudinal direction of the bushing during the charge cycle.

An air, entering into the cylinder of the piston internal combustion engine (PICE) via intake valve (or coming both: through intake valve and through intake ports in the sleeve), flows out through the exhaust ports in the sleeve at the end of the intake stroke and/or at the beginning of the compression stroke. Thus increase (compared with the conventionalPICE) scavenging through the cylinder at full engine loads. In idle running, at low loads and in starting the backflow of exhaust gases into the cylinder is performed. Due to this, the starting is better.

An air, entering into the cylinder of the piston internal combustion engine (PICE) via intake valve (or coming both: through intake valve and through intake ports in the sleeve), flows out through the exhaust ports in the sleeve at the end of the intake stroke and/or at the beginning of the compression stroke. Thus increase (compared with the conventionalPICE) scavenging through the cylinder at full engine loads. In idle running, at low loads and in starting the backflow of exhaust gases into the cylinder is performed. Due to this, the starting is better.

An exhaust gas treatment apparatus includes a treatment cabinet and a catalyst part. To the treatment cabinet, introduced is exhaust gas of an engine which uses gas containing methane as a fuel. The catalyst part is accommodated in the treatment cabinet and oxidizes unburned methane contained in the exhaust gas. When a temperature of the catalyst part is lower than a predetermined normal operating temperature, the catalyst part oxidizes carbon monoxide contained in the exhaust gas and uses oxidation reaction heat of carbon monoxide, to thereby raise the temperature of the catalyst part up to the normal operating temperature or higher. Even when the temperature of the exhaust gas supplied to the catalyst part is lower than the normal operating temperature, it is thereby possible to quickly raise the temperature of the catalyst part up to the normal operating temperature por higher.

To meet stringent emission standards and improve performance of two-stroke crankcase-scavenged engines, the muffler (13) of the engine is provided with mixing means (130, 31) for mixing the exhaust gases (42) resulting from the mixture participating in combustion and gases resulting from scavenging, so that a substantially homogenous gaseous mixture is formed within the muffler (13), and means (81) for sensing oxygen concentration is located in the homogeneous gaseous mixture and are configured to provide an output value to a control unit (80) for controlling supply of fuel to the engine and thereby the air-fuel ratio in the combustion chamber (41). The muffler (13) suitably is provided with a catalytic element (140), preferably a three-way catalyst. The engine (1) preferably is a stratified charge engine.

To meet stringent emission standards and improve performance of two-stroke crankcase-scavenged engines, the muffler (13) of the engine is provided with mixing means (130, 31) for mixing the exhaust gases (42) resulting from the mixture participating in combustion and gases resulting from scavenging, so that a substantially homogenous gaseous mixture is formed within the muffler (13), and means (81) for sensing oxygen concentration is located in the homogeneous gaseous mixture and are configured to provide an output value to a control unit (80) for controlling supply of fuel to the engine and thereby the air-fuel ratio in the combustion chamber (41). The muffler (13) suitably is provided with a catalytic element (140), preferably a three-way catalyst. The engine (1) preferably is a stratified charge engine.

A suction tube of a stratified scavenging engine that can improve the flexibility in designing the shapes and layouts of an air-fuel mixture passage and an air passage; allow for continuous and smooth changes in the shapes of the cross sections of the air-fuel mixture passage and the air passage from the inlet side toward the outlet side; reduce the number of components; and facilitate attachment and assembly; and that is also advantageous in terms of cost is provided. The suction tube includes an air-fuel mixture passage and an air passage, inlet and outlet sides of the passages being connected to a carburetor and a cylinder, respectively; a cylindrical exterior member that mainly forms an outer perimeter portion of each of the air-fuel mixture passage and the air passage; and an interior member for dividing the inside of the cylindrical exterior member into the air-fuel mixture passage and the air passage. With the use of elastic deformation of the interior member or the cylindrical exterior member, the interior member is attached to and integrally formed with the inside of the cylindrical exterior member.

A suction tube of a stratified scavenging engine that can improve the flexibility in designing the shapes and layouts of an air-fuel mixture passage and an air passage; allow for continuous and smooth changes in the shapes of the cross sections of the air-fuel mixture passage and the air passage from the inlet side toward the outlet side; reduce the number of components; and facilitate attachment and assembly; and that is also advantageous in terms of cost is provided. The suction tube includes an air-fuel mixture passage and an air passage, inlet and outlet sides of the passages being connected to a carburetor and a cylinder, respectively; a cylindrical exterior member that mainly forms an outer perimeter portion of each of the air-fuel mixture passage and the air passage; and an interior member for dividing the inside of the cylindrical exterior member into the air-fuel mixture passage and the air passage. With the use of elastic deformation of the interior member or the cylindrical exterior member, the interior member is attached to and integrally formed with the inside of the cylindrical exterior member.