VARIABLE INTAKE DEVICE FOR INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To prevent the occurrence of unevenness in output characteristics between cylinders and to improve the output characteristics of the whole of an internal combustion engine throughout the whole operation region of the internal combustion engine, in an internal combustion engine having an unequal length intake pipe. SOLUTION: A variable intake mechanism 40 to continuously vary the lengths of intake manifolds 31, 32, 33, and 34 according to the number of revolutions of an engine is disposed in a surge tank 23. The variable intake mechanism 40 comprises auxiliary manifolds 41, 42, 43, and 44 movable peripherally of the intake manifolds 31, 32, 33, and 34; and a motor serving as an actuator to peripherally move the auxiliary manifold 41. Further, a relation of (L1 + LS1 )=(L2 +LS2 )=(L3 +LS3 )=(L4 +LS4 ) is established between intake manifold lengths (L1 , L2 , L3 , and L4 ) and auxiliary manifold lengths (LS1 , LS2 , LS3 , and LS4 ).