Four-stroke engine
AssigneeAndreas Stihl AG & Co. KG
InventorsJürgen Häberlein, Roger Ziegler
Life of this patent
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Abstract
A four-stroke engine is provided and has a cylinder and a piston that delimits a combustion chamber and by means of a connecting rod drives a crankshaft disposed in a crankcase. To drive a fuel pump, the fluctuating inner pressure in the crankcase, in the valve housing or in a connecting passage that connects the two housings is utilized. For this purpose, a drive chamber of the fuel pump is connected via a pulse line with a crankcase, a valve housing or the connecting passage.
Claims11
A four-stroke engine comprising a cylinder, and a piston that delimits a combustion chamber and by means of a connecting rod drives a crankshaft disposed in a crankcase, wherein a valve housing is provided and has an intake valve and an exhaust valve for the combustion chamber, wherein said valves are actuated from said valve housing via a valve driving mechanism that is driven by said crankshaft, wherein a mixture preparation device is provided that communicates with the intake valve via an intake channel, wherein an inner chamber of said crankcase is embodied as an essentially closed flow chamber and is in fluid communication with a pulse line, wherein a fuel pump is provided that also communicates with the intake valve via the intake channel and that, via said pulse line, is driven exclusively by pressure pulsations in said crankcase, wherein said four-stroke engine is mixture lubricated, wherein said valve housing is connected with said intake channel of said mixture preparation device and is connected with said crankcase via a connecting passage, and wherein a volume of said inner chamber of said crankcase, a volume of said valve housing and a volume of said connecting passage form a continuous flow chamber.
A four-stroke engine comprising a cylinder, and a piston that delimits a combustion chamber and by means of a connecting rod drives a crankshaft disposed in a crankcase, wherein a valve housing is provided and has an intake valve and an exhaust valve for the combustion chamber, wherein said valves are actuated from said valve housing via a valve driving mechanism that is driven by said crankshaft, wherein a mixture preparation device is provided that communicates with the intake valve via an intake channel, wherein said four-stroke engine is mixture lubricated wherein an inner chamber of said crankcase is embodied as an essentially closed flow chamber and is in fluid communication with a pulse line, and wherein a fuel pump is provided that also communicates with the intake valve via the intake channel and that, via said pulse line, is driven exclusively by pressure pulsations in said crankcase.
A four-stroke engine comprising a cylinder, and a piston that delimits a combustion chamber and by means of a connecting rod drives a crankshaft disposed in a crankcase, wherein a valve housing is provided and has an intake valve and an exhaust valve for the combustion chamber, wherein said valves are actuated from said valve housing via a valve driving mechanism that is driven by said crankshaft, wherein a mixture preparation device is provided that communicates with the intake valve via an intake channel, wherein an inner chamber of said crankcase is embodied as an essentially closed flow chamber and is in fluid communication with a pulse line, wherein a fuel pump is provided that also communicates with the intake valve via the intake channel and that, via said pulse line, is driven exclusively by pressure pulsations in said crankcase, wherein said mixture preparation device is a diaphragm-type carburetor, wherein said fuel pump comprises a drive chamber, a pump chamber and a pump diaphragm that is disposed between the drive chamber and the pump chamber, and wherein said pulse line opens into said drive chamber.
Dependencies are inferred from the claim text.