摘要:
The invention relates to a handheld portable tool driven by a two-stroke engine equipped with a pneumatically actuated injection pump. Injection pumps for two-stroke engines are generally rigidly connected to the engine so that the injection line can be rigid and as short as possible. This, however, leads to operational disturbances in the injection pump. To eliminate these disturbances, the injection pump is mounted in a thermally insulated handle housing portion of the tool which is damped with respect to the vibrations of the engine and is connected to the latter via flexible connecting lines.
摘要:
The invention is directed to a pump for use as a lubricating oil pump in internal combustion engines of handheld portable tools such as motor-driven chain saws or the like. The pump includes a body forming the stator and a body forming the rotor. These bodies lie coaxial with respect to each other and have respective surfaces which lie seal-tight against each other. A screw-shaped spiral slot is formed in one of these surfaces and has an input end connected to a suction connection and an output end connected with a pressure connection. According to a feature of the invention, at least the screw-shaped wall structure is made of an elastomer. This wall structure defines the spiral slot and lies against the smooth surface lying opposite thereto. An absolutely seal-tight contact engagement of the wall structure defining the spiral slot against the opposite-lying surface is assured by the elasticity of the elastomer. The service life of the pump is increased and its production and assembly simplified.
摘要:
The invention relates to a fuel injection arrangement wherein the pump piston of the fuel pump is driven by the pressure in the crankcase of the engine. The fuel injection arrangement includes an opening for tapping the crankcase pressure for actuating a diaphragm in the fuel pump. This opening is controlled by a moving part of the engine such as a crank web or the piston. The moving part closes the opening at least for a portion of the time during which injection occurs thereby delaying the onset of injection to permit a complete combustion during the previous combustion cycle.
摘要:
In a method for controlling a composition of a fuel/air mixture supplied to an internal combustion engine, which engine has a speed control circuit maintaining an actual rotary speed of the crankshaft within preset limits and a controllable metering device for at least one component of the fuel/air mixture, a disruptive variable is introduced into the valve control circuit at a predeterminable point in time, the activity of an engine speed control circuit is monitored and evaluated immediately after introducing the disruptive variable, and, depending on the evaluation result, at least one parameter having an effect on the operation of the internal combustion engine is adjusted.
摘要:
A carburetor (1, 51) has an intake channel (2) wherein a throttle element and a choke element are arranged with the choke element being upstream of the throttle element. The choke element is displaceable between an operating position (8) and at least one starting position (9). A first fuel path is provided which supplies fuel to the intake channel section (2) in dependence upon the underpressure present therein. A first controllable valve (20) for controlling the supplied fuel quantity is mounted in the first fuel path. In order to achieve an adapted fuel supply in different operating states, a second fuel path is provided which defines a bypass line to the first valve (20). A second valve (44, 54) is mounted in the second fuel path. A method for operating the carburetor (1, 51) provides that the second valve (44, 54) is actuated in dependence upon at least one operating parameter of the carburetor (1, 51).
摘要:
The invention is directed to a method for operating a two-stroke engine having a cylinder in which a combustion chamber is formed and which includes devices for metering fuel and supplying combustion air as well as an ignition device for igniting a mixture in the combustion chamber. In the method, fuel and combustion air are supplied to the engine and the mixture in the combustion chamber is ignited. The combustion chamber is delimited by a piston which drives a crankshaft rotatably journalled in a crankcase. A control is provided which controls the metering of fuel and the ignition of the mixture in the combustion chamber. In the method, the two-stroke engine is controlled in at least one operating state so that the number of combustions is less than the number of revolutions of the crankshaft in the same time interval.
摘要:
An internal combustion engine having an intake channel that opens into a crankcase. A first fuel channel opens into the intake channel to supply fuel thereto as a function of underpressure in the intake channel. An auxiliary channel opens into a transfer channel that fluidically connects a crankcase to the combustion chamber. A second fuel channel opens into the auxiliary channel and is connected to a storage reservoir for fuel. At least one valve controls the quantity of fuel to be supplied to the engine via the auxiliary channel. Largely fuel-free air is supplied to the engine via the intake channel during idling. During a first revolution of the crankshaft, fuel is supplied via the auxiliary channel, so that a combustible mixture can form in the combustion chamber. During a second revolution, largely fuel-free air is supplied via the auxiliary channel and the combustion chamber is scavenged with largely fuel-free air.
摘要:
The invention is directed to a method for operating a two-stroke engine having a cylinder in which a combustion chamber is formed and which includes devices for metering fuel and supplying combustion air as well as an ignition device for igniting a mixture in the combustion chamber. In the method, fuel and combustion air are supplied to the engine and the mixture in the combustion chamber is ignited. The combustion chamber is delimited by a piston which drives a crankshaft rotatably journalled in a crankcase. A control is provided which controls the metering of fuel and the ignition of the mixture in the combustion chamber. In the method, the two-stroke engine is controlled in at least one operating state so that the number of combustions is less than the number of revolutions of the crankshaft in the same time interval.
摘要:
A carburetor arrangement is provided for an internal combustion engine that is to be started with a pull cord. A fuel channel that is connected with a fuel-filled storage space opens into and supplies fuel to an intake channel portion as a function of the underpressure in the intake channel portion. The underpressure in the intake channel portion is increased during the start-up process via a start-up mechanism. To keep the engine ready to run with the start-up mechanism engaged, a control valve is disposed between the storage space and where the fuel channel opens into the intake channel portion. The control valve is opened or closed by a control unit as a function of the speed of the internal combustion engine.
摘要:
An ignition circuit for a two-stroke engine has a spark plug (2) which is connected via an ignition switch (14) to a voltage source (16). The ignition switch (14) is actuated via a control circuit (15) in order to close the ignition switch (14) in dependence upon the crankshaft angle and the rpm of the engine (1) and to trigger an ignition spark per revolution of the crankshaft (10). For one and the same rpm, the control circuit (15) makes available an ignition time point for the idle case and an ignition time point for the acceleration case. In order to achieve a rapid acceleration from the idle range, the control circuit (15) monitors the idle rpm in order to switch over to an ignition time point for the acceleration case for a pregiven rpm increase. If the control circuit determines an absence of the rpm increase or even an rpm drop after the ignition switchover to the acceleration case, then there is a switch back to the ignition time point for the idle case.