JPS54113715A - Exhausting device of two-cycle engine - Google Patents

Abstract

PURPOSE: To provide an exhausting device of a two-cycle engine wherein an exhaust pulsating pressure wave is utilized thereby to accelerate exhaustion of air and carry out the supercharging of fresh air in a wide driving range.

CONSTITUTION: At the time where an engine 10 is driven at a low speed, when a control circuit 32 interrupts the current flowing through an electromagnetic solenoid 27 and a first reflection wall 24 within a muffler main body 22 is brought to a parallel position shown by broken line, a negative exhaust pressure wave of exhaust pressure waves propagating through an exhaust pipe 21 is reflected by a diffuser 23 and a positive exhaust pressure wave is reflected by a second reflection wall 29, and propagated again to an exhaust port 14. In the above described reflection wall 29, the course length from an exhaust hole 14 thereto is selected to be a length adapted for the time of operating the engine 10 at a low speed, and a negative exhaust pressure wave reaches the exhaust hole 14 at the time of opening an air extracting hole 13. Also, when a piston 12 begins to rise up from the lower dead point, the positive pressure wave reaches the exhaust hole 14. For this reason, excellent air exhaustion is carried out at the time of the exhausting operation and furthermore at the time of the upstroke of the piston the pressure within the cylinder 11 can be maintained in a high value and also in a supercharged state.

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