Exhaust manifold for internal combustion engine

Abstract

The present invention relates to an exhaust manifold for a supercharger-equipped internal combustion engine having multiple cylinders capable of preventing an increase in the fuel consumption and of reducing load application time. The engine satisfies at least one of the following expressions, where D is the diameter of a main tube of the exhaust manifold, d is the diameter of a branch tube, D 1 is the diameter of a passage of a connection connecting the branch tube to the main tube, R is the radius in the outer peripheral side of the connection smoothly connecting the branch tube to the main tube of the exhaust manifold, and r is the radius in the inner circumference side. 1.2≦(D/d) 2 ≦2.5, 0.8≦(d/de) 2 ≦1.2, 0.7≦(D/D 1 ) 2 ≦1.4, 1.7≦R/r≦2.1.

1 . An exhaust manifold for a supercharger-equipped internal combustion engine having multiple cylinders, characterized in that; 
 the diameter D of a main tube of the exhaust manifold and    the diameter d of a branch tube satisfy the expression of 1.2≦(D/d) 2 ≦2.5.    
   
   
       2 . An exhaust manifold for a supercharger-equipped internal combustion engine having multiple cylinders, characterized in that; 
 the diameter d of a branch tube of the exhaust manifold and the diameter de of an exhaust valve sheet satisfy the expression of 0.8≦(d/de) 2 ≦1.2.    
   
   
       3 . An exhaust manifold for a supercharger-equipped internal combustion engine having multiple cylinders, characterized in that; 
 the diameter D of a main tube of the exhaust manifold and the diameter D 1  of a passage of a connection connecting a branch tube to the main tube satisfy the expression of 0.7≦(D/D 1 ) 2 ≦1.4.    
   
   
       4 . An exhaust manifold for a supercharger-equipped internal combustion engine having multiple cylinders, characterized in that; 
 a branch tube is smoothly connected to a main tube of the exhaust manifold via a connection,    the radius R of the outer peripheral side of the connection, and the radius r of the inner circumference side of the connection satisfy the expression of 1.7≦R/r≦2.1.