Husqvarna Ab

Husqvarna Aktiebolag

Mikael Larsson

Bo P Carlsson

Henrik Eklund

Magnus Ottosson

Lars Andersson

Tore Aronsson

Tomas Wykman

Reine Gustafsson

Björn Lundblad

Mats Lavenius

Mats Roberg

Johan Assargård

Björn Landén

Niklas Enander

Henric Isén

The present disclosure relates to a carburetor assembly () comprising a control unit (), an air channel (), a throttle valve (), a choke valve (), a pulsed fuel valve (), and a fuel supply line (). The control unit () is adapted to control the fuel valve () to supply fuel in accordance with a certain start setting, where the choke valve () can be open or closed. The carburetor assembly () comprises a rotation angle detector assembly () with a choke detector part () that is mounted to a choke shaft () that is connected to the choke valve () such that the choke detector part () is arranged to rotate together with the choke valve (). The rotation angle detector assembly () further comprises a choke sensor device () that is connected to the control unit () and can be affected by the choke detector part () such that the choke sensor device () provides different output signals to the control unit () in dependence of whether the choke valve () is open or closed.

Carburetor assembly start setting detection arrangement

A hand-held power tool comprising an internal combustion engine (), a working tool (), a centrifugal clutch (), and a control system () is disclosed. The engine () has a clutch-in speed, above which the engine () drives the working tool (). The control system () comprises a rotation speed sensor (), and a speed limitation controller (), which is configured to limit an engine speed at a limitation speed below the clutch-in speed. It is active or activated during a starting procedure of the internal combustion engine (). The control system () is configured to deactivate the speed limitation controller () upon sensing at least one acceleration at a level above the limitation speed and sensing at least one deceleration at a level above the limitation speed, such that the engine () is rotatable above the limitation speed to drive the working tool ().

Hand-held power tool and thereto related control system and use and method of controlling

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 () having a fuel supply system including a main fuel path () with an actively controlled fuel valve () and an idling fuel path () branching off from the main fuel path () downstream of the valve (). The fuel supply system further includes a start fuel line () starting upstream (FIG.) or downstream (FIG.) of the fuel valve () and ending in at least one start fuel outlet near and downstream of a choke valve.

Method for controlling the fuel supply to an internal combustion engine at start-up and a carburettor

Herein a hand-held power tool comprising an internal combustion engine () is disclosed. The hand-held power tool comprises, a working tool (), a centrifugal clutch (), and a control system (). The internal combustion engine () has a clutch-in speed (&#x3c9;C) above which the internal combustion engine () drives the working tool (). A speed limitation controller (), is configured to limit an engine speed at a limitation speed below the clutch-in speed (&#x3c9;C). The control system () is configured to calculate an integral of the rotational speed of the internal combustion engine (), and to deactivate the speed limitation controller () after the integral reaches an integration limit value, such that the internal combustion engine () is rotatable above the limitation speed (&#x3c9;L) to drive the working tool () via the centrifugal clutch ().

Hand-held power tool, related control system and its use, and method of controlling said tool

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.

Method for controlling the fuel supply to an internal combustion engine at start-up and a carburetor

Arrangement and methods for communicating data between a control system () of a power tool () and a computing device (). The arrangement () comprises a control system () with a plurality of electronic control units, ECUs (), a computing device (), and a connecting unit () comprising a data connection (). The plurality of ECUs () are connected to a common bus of the control system (). Each of the plurality of ECUs () has a passive service mode () and an active service mode (). The computing device is operable of transmitting a wake-up communication signal to the plurality of ECUs (), which wake-up communication signal comprises an ID of a selected ECU () out of the plurality of ECUs (). The selected ECU () is operable to switch from the passive service mode () to the active service mode () as a response to detecting its ID in the wake-up communication signal, so as to allow communication of data between the selected ECU () and the computing device () via the data connection.

Method for communicating data between a control system of a power tool and a computing device

The invention concerns a method for controlling at least one of a fuel supply and an air supply to an internal combustion engine (), in a fuel supply section thereof, such that an A/F-ratio is adjusted automatically to a desired level. Moreover, the method is activated at a speed close to a cut-out speed threshold () where the engine speed will fluctuate around the threshold () and the method comprises the steps of:

Control of A/F ratio at cut-out speed

A fuel supply unit () is provided e.g. a carburetor or a low pressure injection system of an internal combustion engine. The fuel supply unit () includes a main air passage (), which has a throttle valve () mounted therein and the throttle valve () includes a throttle shaft () extending between two to one another opposite located shaft sides (). A control module () for the fuel supply () is mounted to one () of the shaft sides (), which control module () includes throttle position detecting means () for monitoring the position of the throttle valve (), and fuel valve means () for controlling the fuel supply to the main air passage (). 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 () in the control module () in order to at least control the idle speed of the engine. The ignition system further being arranged to power at least one of the means () of the control module ().

Fuel supply unit

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:

Idle speed control for a handheld power tool

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.

Method for controlling a fuel valve and/or an air valve for an internal combustion engine

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.

Method for adjusting the air-fuel ratio of an internal combustion engine

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.

Growing community of inventors

Jönköping, Sweden

Mikael Larsson