Abstract: A two-stroke combustion engine comprising a user-operated throttle control, an adjustable valve arranged to control one or more air intakes of the combustion engine, and a control unit arranged to control a state of the adjustable valve, wherein the combustion engine is arranged to operate in a first idle mode at an idle engine speed below a clutch engagement engine speed when the user-operated throttle control is not engaged, wherein the combustion engine is arranged to operate in a second idle mode at a target engine speed above the clutch engagement engine speed when the user-operated throttle control is engaged and when the engine is not subject to an external load, the control unit being arranged to control the state of the adjustable valve to maintain engine speed at the target engine speed when the engine operates in the second idle mode.

Abstract: A two-stroke combustion engine comprising a user-operated throttle control, an adjustable valve arranged to control one or more air intakes of the combustion engine, and a control unit arranged to control a state of the adjustable valve, wherein the combustion engine is arranged to operate in a first idle mode at an idle engine speed below a clutch engagement engine speed when the user-operated throttle control is not engaged, wherein the combustion engine is arranged to operate in a second idle mode at a target engine speed above the clutch engagement engine speed when the user-operated throttle control is engaged and when the engine is not subject to an external load, the control unit being arranged to control the state of the adjustable valve to maintain engine speed at the target engine speed when the engine operates in the second idle mode.

Abstract: A two-stroke combustion engine comprising a user-operated throttle control, an adjustable valve arranged to control one or more air intakes of the combustion engine, and a control unit arranged to control a state of the adjustable valve, wherein the combustion engine is arranged to operate in a first idle mode at an idle engine speed below a clutch engagement engine speed when the user-operated throttle control is not engaged, wherein the combustion engine is arranged to operate in a second idle mode at a target engine speed above the clutch engagement engine speed when the user-operated throttle control is engaged and when the engine is not subject to an external load, the control unit being arranged to control the state of the adjustable valve to maintain engine speed at the target engine speed when the engine operates in the second idle mode.

Abstract: The invention concerns a method for controlling the fuel supply to an internal combustion engine at start-up. The fuel supply system can be set in at least two start modes, a lean mode and a rich mode, and the selection of mode is based on an evaluation of a previous start attempt or successful run. The invention also concerns a carburetor (10) having a fuel supply system including a main fuel path (13) with an actively controlled fuel valve (26) and an idling fuel path (14) branching off from the main fuel path (13) downstream of the valve (26). The fuel supply system further includes a start fuel line (23, 423) starting upstream (FIG. 1) or downstream (FIG. 4) of the fuel valve (26) and ending in at least one start fuel outlet near and downstream of a choke valve.

Abstract: The invention concerns a method for controlling the fuel supply to an internal combustion engine at start-up. The fuel supply system can be set in at least two start modes, a lean mode and a rich mode, and the selection of mode is based on an evaluation of a previous start attempt or successful run. The invention also concerns a carburettor (10) having a fuel supply system including a main fuel path (13) with an actively controlled fuel valve (26) and an idling fuel path (14) branching off from the main fuel path (13) downstream of the valve (26). The fuel supply system further includes a start fuel line (23, 423) starting upstream (FIG. 1) or downstream (FIG. 4) of the fuel valve (26) and ending in at least one start fuel outlet near and downstream of a choke valve.

Abstract: The invention concerns a method for controlling the fuel supply to an internal combustion engine at start-up, the engine having a fuel supply system. The invention also concerns a carburetor having a fuel supply system including a main fuel path connecting a diaphragm controlled regulating chamber to a main outlet in the region of the venturi section, the main fuel path including an actively controlled fuel valve, and an idling fuel path branching off from the main fuel path downstream of the valve and ending in at least one idling outlet in the region of a throttle valve, the fuel supply system further including a start fuel line starting upstream or downstream of the fuel valve and ending in at least one start fuel outlet to the intake channel.

Abstract: A fuel supply unit (1) is provided e.g. a carburetor or a low pressure injection system of an internal combustion engine. The fuel supply unit (1) includes a main air passage (3), which has a throttle valve (8, 9) mounted therein and the throttle valve (8, 9) includes a throttle shaft (8) extending between two to one another opposite located shaft sides (6, 7). A control module (2) for the fuel supply (2) is mounted to one (7) of the shaft sides (6, 7), which control module (2) includes throttle position detecting means (30; 300) for monitoring the position of the throttle valve (8, 9), and fuel valve means (60) for controlling the fuel supply to the main air passage (3). Also, an ignition system is provided which is able to control the ignition timing with respect to status of the at least one of the means (30; 300, 40, 60, 100) in the control module (2) in order to at least control the idle speed of the engine.

Abstract: The present invention is related to a retarding device for a hand held cutting machine having a housing (1) and a drive engine, which drives a transmission including a number of transmission members (3?, 2) and driving a rotational or semi rotational cutting tool. The retarding device includes brake means (12, 17) arranged to be in close relation with the transmission and for actuating a retarding force on a transmission member (2), the brake means being arranged to automatically put a retarding force on said transmission member when the speed of rotation or the torque of rotation of said transmission member falls below a predetermined value.

Abstract: The invention concerns a method for controlling the fuel supply to an internal combustion engine at start-up, the engine having a fuel supply system. The invention also concerns a carburetor having a fuel supply system including a main fuel path connecting a diaphragm controlled regulating chamber to a main outlet in the region of the venturi section, the main fuel path including an actively controlled fuel valve, and an idling fuel path branching off from the main fuel path downstream of the valve and ending in at least one idling outlet in the region of a throttle valve, the fuel supply system further including a start fuel line starting upstream or downstream of the fuel valve and ending in at least one start fuel outlet to the intake channel.

Abstract: A method for controlling a valve of a crank case scavenged internal combustion engine includes determining a valve control sequence, wherein the valve is controlled in consecutive periods of revolutions each having a period length of at least ten revolutions, and controlling the valve according to the valve control sequence to adjust the ratio of fuel to air in a combustible mixture delivered to an engine combustion chamber. Determining the valve control sequence for each period includes providing a number of valve shut-off positions, wherein the number of valve shut-off positions corresponds to an amount of fuel or air to be supplied to the engine during the corresponding period, and determining which revolutions of the period that the valve is to be closed.

Abstract: Method for controlling fuel metering in a carburetor or a low pressure injection system of an internal combustion engine when the engine is operating at idle speed, the method includes the steps of: a) monitoring the engine speed; b) determining a first variable (A) based on a first moving average algorithm using the monitored engine speed as input data; c) determining a second variable (B) based on a second moving average algorithm using the monitored engine speed as input data, where the first moving average algorithm is arranged to react faster to an engine speed change than the second moving average algorithm; d) comparing the second variable (B) to the first variable (A), where if 1) the second variable (B) is higher than the first variable (A): the fuel metering is set in a first leaner setting, and where if 2) the second variable (B) is lower than the first variable (A): the fuel metering is set in a second richer setting.

Abstract: Method for adjusting the air-fuel ratio of an internal combustion engine, in a fuel supply section thereof, such as a carburettor or a fuel-injection system, the fuel supply section having a control unit for adjusting the air-fuel ratio of the engine, and the engine having an engine speed and an engine throttle ranging from zero throttle to full throttle. The method including: a) measuring the engine speed of the engine; b) comparing the engine speed to a first engine speed value; c) adjusting the air fuel ratio if the engine speed is lower than the first engine speed value; and d) repeating a) to c) until the engine speed is either greater than or equal to the first engine speed value.

Abstract: A fuel supply unit (1) is provided e.g. a carburetor or a low pressure injection system of an internal combustion engine. The fuel supply unit (1) includes a main air passage (3), which has a throttle valve (8, 9) mounted therein and the throttle valve (8, 9) includes a throttle shaft (8) extending between two to one another opposite located shaft sides (6, 7). A control module (2) for the fuel supply (2) is mounted to one (7) of the shaft sides (6, 7), which control module (2) includes throttle position detecting means (30; 300) for monitoring the position of the throttle valve (8, 9), and fuel valve means (60) for controlling the fuel supply to the main air passage (3). Also, an ignition system is provided which is able to control the ignition timing with respect to status of the at least one of the means (30; 300, 40, 60, 100) in the control module (2) in order to at least control the idle speed of the engine.

Abstract: The present invention provides a method for manufacturing a biocompatible precious metal alloy object. According to a first aspect melting of alloying elements and casting of the biocompatible precious metal alloy are carried out in a process chamber (11) being provided with a process gas of predetermined composition. A burning flame (19) of a hydrocarbon-containing gas provides low oxygen and water content. According to a second aspect post-processing of a precious metal alloy is made in atmosphere provided by the process gas to form the biocompatible precious metal alloy object. The biocompatible precious metal alloy object manufactured according to the invention has a low probability of causing sensitisation when in contact with the human body.

Abstract: Method for controlling fuel metering in a carburetor or a low pressure injection system of an internal combustion engine when the engine is operating at idle speed, the method includes the steps of: a) monitoring the engine speed; b) determining a first variable (A) based on a first moving average algorithm using the monitored engine speed as input data; c) determining a second variable (B) based on a second moving average algorithm using the monitored engine speed as input data, where the first moving average algorithm is arranged to react faster to an engine speed change than the second moving average algorithm; d) comparing the second variable (B) to the first variable (A), where if 1) the second variable (B) is higher than the first variable (A): the fuel metering is set in a first leaner setting, and where if 2) the second variable (B) is lower than the first variable (A): the fuel metering is set in a second richer setting.

Abstract: The present invention is related to a retarding device for a hand held cutting machine having a housing (1) and a drive engine, which drives a transmission including a number of transmission members (3?, 2) and driving a rotational or semi rotational cutting tool. The retarding device includes brake means (12, 17) arranged to be in close relation with the transmission and for actuating a retarding force on a transmission member (2), the brake means being arranged to automatically put a retarding force on said transmission member when the speed of rotation or the torque of rotation of said transmission member falls below a predetermined value.

Abstract: A method for controlling an ignition system of an internal combustion engine having a primary firing pulse generator for charging a capacitor. An electronic switch is included for discharging the capacitor via an ignition coil to generate an ignition voltage. A microcomputer operates the switch to control the ignition timing of the generator. The microcomputer is in communication with a speed sensor that detects the rotational speed of the engine and a speed limitation control that limits the engine speed to a limitation speed below the clutch-in speed of an included centrifugal clutch. The speed limitation control is active or activated when one of either starting the engine or an operating problem of the power tool is detected. The speed limitation control is deactivated when a low speed state of the engine is detected.

Abstract: Crankcase scavenged two-stroke internal combustion engine (1), in which a piston ported air passage is arranged between an air inlet (2) and the upper part of a number of transfer ducts (3, 3?). The air passage is arranged from an air inlet (2) equipped with a restriction valve (4), controlled by at least one engine parameter, for instance the carburetor throttle control. The air inlet extends via at least one connecting duct (6, 6?) to at least one connecting port (8, 8?) in the engine's cylinder wall (12). The connecting port (8, 8?) is arranged so that it in connection with piston positions at the top dead center is connected with flow paths (10, 10?) embodied in the piston (13), which extend to the upper part of a number of transfer ducts (3, 3?).

Abstract: A method for controlling a valve of a crank case scavenged internal combustion engine includes determining a valve control sequence, wherein the valve is controlled in consecutive periods of revolutions each having a period length of at least ten revolutions, and controlling the valve according to the valve control sequence to adjust the ratio of fuel to air in a combustible mixture delivered to an engine combustion chamber. Determining the valve control sequence for each period includes providing a number of valve shut-off positions, wherein the number of valve shut-off positions corresponds to an amount of fuel or air to be supplied to the engine during the corresponding period, and determining which revolutions of the period that the valve is to be closed.

Abstract: A method for controlling an ignition system of an internal combustion engine having a primary firing pulse generator for charging a capacitor. An electronic switch is included for discharging the capacitor via an ignition coil to generate an ignition voltage. A microcomputer operates the switch to control the ignition timing of the generator. The microcomputer is in communication with a speed sensor that detects the rotational speed of the engine and a speed limitation control that limits the engine speed to a limitation speed below the clutch-in speed of an included centrifugal clutch. The speed limitation control is active or activated when one of either starting the engine or an operating problem of the power tool is detected. The speed limitation control is deactivated when a low speed state of the engine is detected.