A guard tube assembly for a drive shaft of a power tool has a guard tube with a tube cross section deviating from a circular shape and having an inner contour and a center. An inner support tube inside the guard tube supports the drive shaft. The inner support tube has a bearing sleeve supported by support elements on the inner contour. The inner contour has a first and a second circumferential section. The first circumferential section has a smallest spacing to the center and the second circumferential section has a largest spacing to the center. The elastic support elements have a contact surface contacting the inner contour and spaced at a contact surface spacing to the center. The contact surface spacing is longer than the smallest spacing of the first circumferential section and shorter than or identical to the largest spacing of the second circumferential section.

A gas powered internal combustion engine in which the gas is provided from the gas phase of a pressurized liquid gas in an liquified petroleum gas container and in which the liquified petroleum gas container is rigidly mounted adjacent to the internal combustion engine at a preselected angle to be in conductive heat transfer relationship to the internal combustion engine and in vibration receiving relationship to the internal combustion engine whereby the liquified gas in the liquified petroleum gas container is heated and vibrated and the effective surface area thereof is thereby increased. A pressure regulator is provided for receiving the gas from the liquified petroleum gas bottle regulating the pressure of the gas transmitted to the internal combustion engine and at least one flexible hose is connected to the pressure regulator for transmitting the gas therethrough. A vibration and/or heat limiting member may be incorporated to reduce the frequence and amplitude of the vibration and limit the amount of heat transferred to the liquified petroleum gas.

A tiller includes an engine, a mobility assembly, and a rotating assembly. The mobility assembly is operably coupled to the engine to provide mobility of the tiller responsive to operation of the engine. The rotating assembly is selectively coupled to the engine to provide rotation of the rotating assembly. The rotating assembly includes a rotatable shaft configured to turn when the rotation assembly is operably coupled to the engine, and one or more sets of tines disposed on respective tine assemblies. Each of the tine assemblies includes a hollow shaft for receiving the rotatable shaft. The one or more sets of tines extend radially outward from the respective tine assemblies.

A tiller includes an engine, a mobility assembly, and a rotating assembly. The mobility assembly is operably coupled to the engine to provide mobility of the tiller responsive to operation of the engine. The rotating assembly is selectively coupled to the engine to provide rotation of the rotating assembly. The rotating assembly includes a rotatable shaft configured to turn when the rotation assembly is operably coupled to the engine, and one or more sets of tines disposed on respective tine assemblies. Each of the tine assemblies includes a hollow shaft for receiving the rotatable shaft. The one or more sets of tines extend radially outward from the respective tine assemblies.

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.

The disclosure provides a two-cycle engine and an engine work machine. When a piston is located on the side of a bottom dead center, at a part corresponding to a notch part in the piston, an inner surface of the crank case protrudes toward an interior side to form a crank case first protruding part penetrating through the notch part toward the interior side. Meanwhile, the crank case at a part corresponding to a part without the notch part in the piston is not in a shape protruding toward the interior side. By assembling the piston and the crank case in such shapes, the piston is able to reciprocally move up and down without interfering with the crank case. In this case, by disposing the crank case first protruding part, the volume in the crank case is able to be reduced.

The disclosure provides a two-cycle engine and an engine work machine. When a piston is located on the side of a bottom dead center, at a part corresponding to a notch part in the piston, an inner surface of the crank case protrudes toward an interior side to form a crank case first protruding part penetrating through the notch part toward the interior side. Meanwhile, the crank case at a part corresponding to a part without the notch part in the piston is not in a shape protruding toward the interior side. By assembling the piston and the crank case in such shapes, the piston is able to reciprocally move up and down without interfering with the crank case. In this case, by disposing the crank case first protruding part, the volume in the crank case is able to be reduced.

A method for operating an internal combustion engine of a motor vehicle, whereby an electrically heated component of an exhaust aftertreatment system being supplied with electrical power via an electric machine driven by the internal combustion engine, a load point shift of the internal combustion engine being carried out by an activation or a deactivation of the component or by a temporary storage of the necessary electrical energy for operating the component in a battery.

Gas-engine replacement devices described herein include a housing that includes battery receptacle configured to removably receive a battery pack, a motor located within the housing, a power take-off shaft receiving torque from the motor and protruding from a side of the housing, a power switching network configured to selectively provide power from the battery pack to the motor, and an electronic processor. The electronic processor is coupled to the power switching network and configured to receive a current measurement associated with the motor and control the power switching network according to one of a freewheeling mode or a synchronous rectification mode based on the current measurement.