EXHAUSTER FOR ENGINE

PURPOSE:To prevent exhaust gas from blowing through cylinders by varying the opening timing of each exhaust port in an assembly where each cylinder is provided with two exhaust ports connected to a supercharger, and exhaust passages connected to these exhaust ports are caused to aggregate in a prescribed state. CONSTITUTION:On each cylinder 2A-2D (hereafter, the annexed letters are omitted) of a four-cylinder engine are provided two exhaust ports 5, 6 respectively, and then, to each of these exhaust ports 5, 6 are connected the No.1 and No.2 exhaust passages 9, 10. Each of these exhaust passages 9, 10 is connected to a pair of exhaust introduction passages 11, 12 on either side of an exhaust gas turbosupercharger 20. In addition, each of these exhaust ports 9, 10 is caused to aggregate at either of the No.1 and No.2 cylinder groups X1, X2, consisting of cylinders 2A, 2B; 2C, 2D located in the order of their sequential ignition, so as to form exhaust passage units 31, 32; 33, 34, and then, on the aggregate part of the exhaust introduction passages 11, 12 in each of the units 33, 34 are provided control valves 14, 14. And further, in the constitution as mentioned above, the opening timing of the No.2 exhaust port 6 is set such that it is by a fixed time behind that of the No.1 exhaust port 5.