Intake system of a V-type engine

An intake system of a V-type engine comprising a surge tank extending in a cylinder-row direction above a space between first and second cylinder banks of the V-type engine;

• a first intake pipe of an intake manifold having one end thereof connected to a second side of said surge tank which faces said second cylinder bank, and a second intake pipe of the intake manifold having one end thereof connected to a first side of said surge tank which faces said first cylinder bank, said first and second intake pipes having one ends thereof bent and turned in the vicinities of said second and first cylinder banks respectively and having middle portions thereof crossing below said surge tank and having the other ends thereof connected to said first and second cylinder banks respectively, said first and second intake pipes which are connected to said first and second cylinder banks respectively being arranged in an alternating position in the cylinder-row direction;
• first and second branch pipes having one ends thereof inserted into said surge tank and the other ends thereof connected to adjacent respective other ends of said first and second intake pipes;
• variable intake members to open and close first and second branch passages of said first and second branch pipes respectively, said variable intake members being disposed at one ends of said first and second branch pipes which are inserted into said surge tank;
• said intake pipes and said branch pipes being divided into an upper block member toward said surge tank and a lower block member toward said cylinder banks by a dividing surface at substantially the same level as a lower part of said surge tank;
• said upper block member defining first and second intake pipe parts, and first and second upper branch pipe parts;
• said lower block member defining first and second lower intake pipe parts, and first and second lower branch pipe parts;
• said upper and lower block members having respective upper and lower surfaces defining said dividing surface;
• and
• one ends of said upper branch pipe parts being disposed above said dividing surface and having said variable intake elements therein.

An intake system of a V-type engine, comprising:

• a single surge tank disposed above and between first and second cylinder banks of said V-type engine, said surge tank having first and second outermost opposite sides;
• first and second intake passages defined by respective first and second intake pipes branching from said second and first outermost opposite sides, respectively, said first intake pipe having a first end opening inwardly and toward said first opposed side of said surge tank, said second intake pipe having a first end opening inwardly and toward said second opposed side of said surge tank, said intake passages adjacent said first ends having regions inversely bent in the vicinity of the respective cylinder banks and crossing below said surge tank, said first and second intake passages having other ends thereof connected to said first and second cylinder banks respectively;
• first and second branch passages branching from said first and second intake passages respectively and connected to a lower part of said surge tank, said first and second branch passages protruding upwardly through a bottom of said surge tank to upper ends of said branch passages, said upper ends disposed within said surge tank and between said intake pipes, said first and second branch passages having lower ends connected to said first and second intake passages adjacent said first and second cylinder banks, respectively, said first and second branch passage having longitudinal axes thereof inclined toward a center longitudinally-extending axis generated in the cylinder-row direction between said cylinder banks and disposed within said surge tank, said branch passage longitudinal axes transversely intersecting with said center longitudinally-extending axis;
• and
• a valve system to open and close said first and second branch passages, said valve system having a rotating shaft thereof disposed substantially coaxial with said center longitudinally-extending axis.

An intake system of a V-type engine comprising:

• a single surge tank disposed above and between first and second cylinder banks of the V-type engine;
• intake passages branching from sides of said surge tank and having portions bent inversely and crossing each other below the surge tank to connect to said cylinder banks;
• first and second said intake passages connecting to intake ports of said first and second cylinder banks respectively and disposed below said surge tank in a cylinder-row direction;
• a tank passage formed in said surge tank between the bent portions of said first and second intake passages;
• first and second branch passages branching from said first and second intake passages respectively so as to connect to said tank passage;
• said branch passages being formed in a straight shape and generally aligned with a respective intake port;
• said first and second branch passages having longitudinal center axes which are inclined toward a center longitudinally-extending axis defined between said cylinder banks and which intersect within said tank passage when viewed in the longitudinal direction of the engine banks;
• and
• a valve system to open and close one ends of said first and second branch passages, including rotating shaft extending along the intersection of said first and second branch passage longitudinal axes.