A two-stroke engine possesses a cylinder, in the cylinder bore of which a combustion chamber is formed. The combustion chamber is bounded by a reciprocating piston, which drives a crankshaft rotatably mounted in a crankcase. A crankcase interior is fluidically connected to the combustion chamber across at least one transfer channel in at least one position of the piston. The at least one transfer channel emerges with a discharge opening in the crankcase interior and with at least one transfer window on the cylinder bore. It is proposed that all transfer channels have an average length as measured from the discharge opening to the transfer window, the average length being at least 1.5 in relation to the stroke, and that the volume of the crankcase interior including all transfer channels is at most 3.1 in relation to the piston displacement.

A two-stroke engine includes a cylinder having a combustion chamber. The combustion chamber is delimited by a piston guided in a reciprocating manner in the cylinder and drives a crankshaft. A first intake channel opens into the crankcase interior. A transfer channel opens into the crankcase interior via a transfer window on a cylinder bore of the cylinder and via a passage opening. A second intake channel is provided for supplying scavenging air to the transfer channel. The first intake channel and the second intake channel are configured for supplying air. An injection valve configured for injecting the entire quantity of fuel to be supplied to the engine directly into the crankcase interior is disposed on the crankcase. A method for operating a two-stroke engine provides that the entire quantity of fuel to be supplied to the engine via a metering installation is supplied directly to the crankcase interior.

A carburetor for the combustion engine in a handheld work apparatus has a carburetor housing in which a carburetor drum is mounted rotatably about a pivot axis. The carburetor drum has a drum body which has at least one channel which runs transversely with respect to the pivot axis and forms an intake channel portion. A sensing unit for sensing at least one rotational position of the carburetor drum is provided. The sensing unit includes a control contour and a sensing device interacting with the control contour. The control contour is formed on the carburetor drum. A method for operating a combustion engine makes provision for the control device to control the supplied quantity of fuel depending on the rotational position, sensed by the sensing unit, of the carburetor drum.

In order to provide a method for indicating a risk of corrosion or scuffing of components of a combustion chamber of a turbo charged engine arrangement, in particular for vessels, the turbo charged engine arrangement includes a turbocharger and a charge gas cooler. A first gas stream of an ambient gas enters into the turbocharger, a second gas stream of charge gas flows from the turbocharger to the charge gas cooler, and the second gas stream of charge gas enters into the charge gas cooler. A third gas stream of charge gas flows from the charge gas cooler to the combustion chamber, and the third gas stream of the charge gas enters into the combustion chamber.

A method for controlling a two-stroke engine operatively connected to a turbocharger, the turbocharger being in fluid communication with the engine to provide a boost pressure thereto. The method includes determining an exhaust temperature representative of an actual temperature of exhaust gas being discharged by the engine; determining a temperature difference between the exhaust temperature and a threshold temperature; in response to the exhaust temperature being less than the corresponding threshold value: determining a corrective amount of boost pressure to add to the boost pressure of the turbocharger, the corrective amount of boost pressure being determined based on the temperature difference; and controlling the turbocharger to increase the boost pressure of the turbocharger by the corrective amount.

An opposed piston engine includes approximately spherical combustion chamber formed by the two opposed pistons in a single cylinder and an intake manifold including gas hooks. The combustion chamber has a small cone shaped extension on each side leading to each of two opposed injectors located in the cylinder wall where the two pistons meet at the top of their stroke. The combustion chamber configuration reduces the surface area of the chamber and increases the burn length by a significant amount compared to known designs. The gas hooks in the intake manifold restrict the flow of exhaust gases into the intake manifold long enough for the pressure in the cylinder to blow down and the exhaust gasses to attain high velocity passing out through the exhaust manifold, allowing the intake ports to be uncovered before the exhaust ports.

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.

To improve the effect of preventing contamination of an element in an air cleaner. An air cleaner includes a first inlet (60) through which air is fed to an intake system air passage and a second inlet (62) through which air is fed to an intake system air-fuel mixture passage. An extended passage (72) leads to the second inlet (62), for example. A passage forming member (70, 204) forming the extended passage (72) is shaped to surround a periphery of the first inlet (60). The passage forming member (70, 204) forms a blown-back fuel diffusion preventing region (74) leading to the first inlet (60).

A carburetor achieves better emission characteristics while improving a combustion state by increasing a delivery ratio of a stratified scavenging engine and reducing intake resistance. No dividing wall is provided between a throttle valve 204 and a choke valve 242, and a gap 244 between the valves 204 and 242 is opened. Intake air in both of an upper region and a lower region of the choke valve 242 flows into an air-fuel mixture passage 246 in a lower region of the fully-open throttle valve 204. A main nozzle 202 is arranged so as to be inclined toward the throttle valve 204.

An opposed piston engine includes approximately spherical combustion chamber formed by the two opposed pistons in a single cylinder and an intake manifold including gas hooks. The combustion chamber has a small cone shaped extension on each side leading to each of two opposed injectors located in the cylinder wall where the two pistons meet at the top of their stroke. The combustion chamber configuration reduces the surface area of the chamber and increases the burn length by a significant amount compared to known designs. The gas hooks in the intake manifold restrict the flow of exhaust gases into the intake manifold long enough for the pressure in the cylinder to blow down and the exhaust gasses to attain high velocity passing out through the exhaust manifold, allowing the intake ports to be uncovered before the exhaust ports.