METHOD AND APPARATUS FOR SUPPRESSING THE EXHAUST NOISE OF FOUR-STROKE INTERNAL COMBUSTION ENGINE Russian patent published in 1994 - IPC

FIELD: automotive engineering. SUBSTANCE: cyclic portion of exhaust gases is split into two portions of which one is discharged to the outside and the other is conveyed to another chamber. After the process of gas discharge is terminated the gases are directed to the first chamber to be discharged to the atmosphere. Device for carrying out the method has casing 1 separated by partition 2 into main and damping cavities 3 and 4, exhaust pipe 5 located in the main cavity, and intermediate pipe 6 in the form of a spiral made integral with inlet pipe and having port 8 extending into the main cavity. Open end of pipe 6 extends into the damping cavity. A reduction in the pressure downstream of the discharge arrangement is accounted for by two underpressure waves reflected from port 8 and open end of the intermediate pipe 6, and by that exhaust gases enter main cavity 4 in two flows. Second portion is delayed in time thanks to substantial length of intermediate pipe 6. EFFECT: enhanced efficiency of the method and apparatus. 2 cl, 2 dwg