Abstract: A two-stroke engine according to the present invention includes: a separating wall which confines a tip end portion of an ignition device; an ignition promoting chamber which is formed by means of the separating wall, is independent of a combustion chamber, and encloses the tip end portion of the ignition device; and a plurality of communicating holes which are provided in the separating wall, each of which is provided with a first opening that opens in the combustion chamber and a second opening that opens in the ignition promoting chamber, and which provide communication between the combustion chamber and the ignition promoting chamber.

Abstract: A two-stroke engine (4) has a throttle motor (22) for driving a throttle valve (20), a fuel injection device (430) disposed in an intake system (18) including a crank chamber (420), and a control unit (24) controlling the throttle motor (22) and the fuel injection device. The two-stroke engine (4) is designed to achieve an engine rotation speed of 4,500 rpm to 7,000 rpm when the throttle valve (20) is fully open. The two-stroke engine (4) is operated with the throttle full open by the control unit (24), and a battery (8) is charged with electric power generated by a generator (6) using the two-stroke engine.

Abstract: A cost-effective muffler for a stratified scavenging engine capable of reducing the number of cells with no exhaust gas flowing in a columnar catalyst as much as possible to create a uniform exhaust gas flow in the columnar catalyst and thus obtaining a desired exhaust gas purification rate, so that THC emissions can be effectively curbed, without substantial alteration or dimensional changes to an existing muffler body and columnar catalyst. At least one of distances: from introduction port to partitioning wall plate; from front wall surface of front chamber to front end surface of the columnar catalyst; and from partitioning wall plate to front end surface of the columnar catalyst is within a predetermined range to prevent gas flow introduced into the front chamber through the introduction port and hitting against the partitioning wall plate to be reversed from bypassing cells in the upper end portion of the columnar catalyst as much as possible.

Abstract: A two-stroke engine (4) has a throttle motor (22) for driving a throttle valve (20), a fuel injection device (430) disposed in an intake system (18) including a crank chamber (420), and a control unit (24) controlling the throttle motor (22) and the fuel injection device. The two-stroke engine (4) is designed to achieve an engine rotation speed of 4,500 rpm to 7,000 rpm when the throttle valve (20) is fully open. The two-stroke engine (4) is operated with the throttle full open by the control unit (24), and a battery (8) is charged with electric power generated by a generator (6) using the two-stroke engine.

Abstract: Provided is power work equipment using a fuel container and/or a lubricating oil container that is/are easily replaced for the power work equipment, and supply(ies) liquid fuel and/or lubricating oil optimized for driving. A chainsaw (1A) (power work equipment) includes a main body (10) having an internal combustion engine (50), and a fuel container (90A) and/or a lubricating oil container (100A) detachably attached to the main body (10). A connection part (92) of the fuel container (90A) is connected with the fuel suction unit (60) in a liquid-tight manner, and the bag (91) is configured to collapse as liquid fuel (F) in the bag (91) decreases. A connection part (102) of the lubricating oil container (100A) is connected with a lubricating-oil suction unit (70) in a liquid-tight manner, and a bag (101) is configured to collapse as lubricating oil (L) in the bag (101) decreases.

Abstract: A handheld engine-driven working machine comprises an internal combustion engine and an ignition control device; wherein the ignition control device can switch its control between a normal mode and a operation mode, wherein during the operation mode, the ignition timing within the high speed range is maintained at a second BTDC angle, and the ignition timing within the medium speed range is advanced more than a third BTDC angle between a first BTDC angle and the second BTDC angle, and wherein at any rotational speed within the medium speed range, the ignition timing during the operation mode is advanced more than the ignition timing during the normal mode.

Abstract: A handheld engine-driven working machine comprises an internal combustion engine with a throttle valve, a throttle adjusting device for adjusting an opening degree of the throttle valve of the internal combustion engine, and a control device provided in the internal combustion engine. The control device is configured to detect a rotational speed and an amount of change in the rotational speed at every at least one rotation of the internal combustion engine. The control device determines that the throttle valve is partially opened when the amount of change in the rotational speed is greater than a predetermined value.

Abstract: A handheld engine-driven working machine comprises an internal combustion engine and an ignition control device; wherein the ignition control device can switch its control between a normal mode and a operation mode, wherein during the operation mode, the ignition timing within the high speed range is maintained at a second BTDC angle, and the ignition timing within the medium speed range is advanced more than a third BTDC angle between a first BTDC angle and the second BTDC angle, and wherein at any rotational speed within the medium speed range, the ignition timing during the operation mode is advanced more than the ignition timing during the normal mode.

Abstract: A handheld engine-driven working machine comprises an internal combustion engine with a throttle valve, a throttle adjusting device for adjusting an opening degree of the throttle valve of the internal combustion engine, and a control device provided in the internal combustion engine. The control device is configured to detect a rotational speed and an amount of change in the rotational speed at every at least one rotation of the internal combustion engine. The control device determines that the throttle valve is partially opened when the amount of change in the rotational speed is greater than a predetermined value.