The invention relates to a method for operating a piston type internal combustion engine. The engine comprises a fuel-injected device and each cylinder comprises at least one outlet valve communicated with a gas exhaust gas system, and at least one inlet valve connected with an air inlet system. The engine also comprises a means for increasing the boost pressure in the air inlet system. A control device for variably adjusting at least the opening times of the inlet valves is provided. The inlet opening times of the inlet valves within the lower engine speed range can be adjusted via the control device in such a manner that there is a valve overlap with the closing time of the corresponding outlet valves. Therefore, the cylinder is scavenged with fresh charge air before and/or during charge exchange in the area of top dead center. The ratio of residua gas in the cylinder that has been scavenged is at least up to 95 %. When the rotating speed of the internal combustion engine is up to 2000 revolutions per minute, the opening/closing times of the valves is adjusted.