Exhaust-port control slide for two-stroke engines

摘要

Designation of the invention: exhaust-port control slide for two-stroke engines. Area of technical application: high-speed, port-controlled two-stroke engines. Technical problem: in order to guarantee satisfactory functioning of these engines, the piston must, to end the power stroke, first of all open part of the exhaust port (preliminary outlet) before it begins to free the scavenging ducts and hence initiate the scavenging process. Due to the fact that the timing diagram of these engines is symmetrical, the preliminary outlet is still open on completion of the scavenging process by the upward-moving piston. This leads to losses of fresh gas, a situation which should be avoided. Solution to the problem: the problem is solved, according to the invention, by the fact that a rotatably mounted slide (Figure 1) is installed in the exhaust duct, the said slide freeing the preliminary outlet duct fully, partially or not at all depending on the angle of rotation of the crankshaft. The slide can, for example, be driven by a toothed belt. Main area of application: in high-power two-stroke vehicle engines with a wide useful engine-speed range, the volumetric efficiency and hence the power and torque curves can be improved by means of the abovementioned device. <IMAGE>