Andreas Stihl Ag Co. Kg

Tim Gegg

Wolfgang Layher

Georg Maier

Klaus Langhans

Manuel Dangelmaier

Andreas Neubauer

Arno Kinnen

Sebastian Hanussek

Clemens Klatt

Gerd Densborn

Heiko Roβkamp

Jörg Elfner

Christian Schmidt

Armin Koelmel

Christine Hallé

Martin Strauss

A handheld work apparatus has a combustion engine () for driving a tool. The combustion engine () has an ignition device, a device for metering fuel and a control device (). The control device () engages when an engagement speed (n, n) is reached, in order to limit the speed (n) of the combustion engine (). In order to allow the speed (n) to be set in an easy manner at full throttle, the work apparatus has a device for setting the engagement speed (n) by the user.

Handheld work apparatus

A work apparatus has an internal combustion engine and a starter device for starting the engine. Within a housing of the work apparatus, a first electrical component is arranged at a first location and a second electrical component is arranged at a second location. A control unit is provided which is connected to the first electrical component and to the second electrical component. The control unit detects a first temperature-dependent value of the first electrical component at the first location, and a second temperature-dependent value of the second electrical component at the second location, and identifies the starting conditions as a function of these values. The first electrical component is a first actuator and the second electrical component is a second actuator or a sensor.

Work apparatus and method for determining the starting conditions thereof

A method controls the rpm of a combustion engine in a hand-held work apparatus such as a brushcutter. The engine drives a work tool via a clutch which engages as a function of the engine rpm (n). A spark plug is arranged in the combustion chamber and is driven by an ignition unit. During start of the engine, an rpm lock circuit is active and defines a control variable as a function of the instantaneous rpm (n) of the engine. According to the magnitude of this control variable, operating parameters of the engine are adapted to change the instantaneous rpm (n). A control variable is determined for the adaptation of the operating parameters by the rpm lock circuit. The switch-off of the rpm lock circuit is provided when the control variable of the control lies outside a predetermined bandwidth of the absolute magnitude of the control variables.

Method for switching off a rotational speed limit in an internal combustion engine

The invention relates to a portable, handheld work apparatus such as a trimmer, a cut-off machine, a chain saw or the like, having a motor () to drive a rotating, exchangeable work tool (). A control unit () serves to control the operation of the motor (). The control unit () determines the rotational speed (n) and/or the power (P) of the motor (). According to the invention, the motor () can be operated in a first operating mode (I) with reduced rotational speed (n) and/or power (P) and in at least a second operating mode (II) with an increased rotational speed (n) and/or power (P). In dependence on a release signal, the control uses exclusively the first operating mode (I) for a limited operation and the second operating mode (II) for an expanded operation.

Handheld work apparatus with switchable power

A centrifugal clutch, especially in a hand held work apparatus, such as a cut-off machine (), a brush cutter or the like, having a rotational axis (), at least one movably mounted centrifugal weight () arranged at the drive end and a clutch drum () arranged at the output end. The centrifugal clutch () includes a brake device () which is released by the centrifugal weight () when the centrifugal weight () moves radially outward in relation to the rotational axis ().

Centrifugal clutch

An internal combustion engine () has an ignition device, a device for supplying fuel and a device for detecting the rpm of the engine (). The engine () includes a permissible limit rpm (n) and a control range (A) of the rpm (n) above the limit rpm (n). A method for operating the engine () provides that the rpm of the engine () is limited in the control range (A) because of suppression of the ignition in individual engine cycles wherein the rpm (n) lies above a control rpm (n) lying in the control range (A). In the control range, and to improve the exhaust-gas values, the noncombustion engine cycle ratio (NECR) is adjusted. The NECR indicates the ratio of the number of engine cycles wherein the ignition is suppressed to the total number of ignitions.

Method for operating an internal combustion engine

A method for operating an internal combustion engine having a fuel system which feeds fuel at a given pressure to a metering valve provides that a controller defines the opening time and the closing time of the metering valve and correspondingly actuates the metering valve so that the metering valve opens and closes at the defined times. In order to permit precise metering of fuel even in high-speed internal combustion engines there is provision for the controller to define at least one of the times for the opening or closing of the metering valve while taking into account the counterpressure actually prevailing at the outlet opening of the metering valve.

Growing community of inventors

Remseck, Germany

Tim Gegg