Abstract: A four-stroke engine lubrication system comprises: an engine body in which a crank shaft chamber and an air valve distribution chamber are arranged; a cylinder head cover fixed onto the engine and communicated with the atmosphere; and an oil storage tank which is configured to store lubricating oil, arranged on the engine body, located at one side of a cam, and provided with an oil mist generation device therein, wherein an oil outlet passage of the oil mist generation device communicates the oil storage tank with the crank shaft chamber via an oil outlet pipe; the crank shaft chamber is communicated with the air valve distribution chamber via a check valve; the air valve distribution chamber is communicated with the oil storage tank via a pipe; the air valve distribution chamber is communicated with the cylinder head cover; and the cylinder head cover is communicated with the oil storage tank.

Abstract: The present utility model discloses a portable four-stroke engine, comprising: an engine body, a flywheel and an oil storage tank, wherein an air valve distribution chamber and a crank shaft chamber are arranged in the engine; a crank shaft is arranged in the crank shaft chamber, and is connected to the flywheel; the oil storage tank is arranged on the engine body, located above the flywheel, and configured to store lubricating oil; a cam and a rocker arm mechanism are arranged in the air valve distribution chamber; and the cam is configured to drive the rocker arm mechanism. The portable four-stroke engine provided by the present utility model has a small volume and therefore has better operation performance.

Abstract: The present invention discloses an oil-gas dual-purpose integrated switch. The oil-gas dual-purpose integrated switch comprises a valve and a knob switch for controlling an ignition coil and a carburetor solenoid valve; the valve cap is fixed on the valve body to form a valve cavity; the valve core is disposed in the valve body; the valve core passes through the valve cap to be fixed with the knob of the knob switch such that when the knob switch is rotated, the valve core is driven to rotate; the valve body is provided with an oil inlet pipe joint, an oil outlet pipe joint, a gas inlet pipe joint and a gas outlet pipe joint which are communicated with the valve cavity; the valve core is provided with an oil duct, and a gas duct. The oil-gas dual-purpose integrated switch can switch the oil path and the gas path randomly.