Intake system of a multi-cylinder internal combustion engine
AssigneeToyota Jidosha Kogyo Kabushiki Kaisha
InventorsKiyoshi Nakanishi, Katsuhiko Motosugi
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Abstract
A multi-cylinder internal combustion engine comprising a plurality of cylinders each having a helically-shaped intake port. The helically-shaped intake port comprises a helical portion having the outlet open end, and an inlet passage portion having an inlet open end and tangentially connected to the helical portion. The intake valve is arranged in the outlet open end. The engine further comprises a common connecting passage and a plurality of branch connecting passages each being in communication with the common connecting passage. Each of the branch connecting passages opens into the inlet open end of the corresponding helically-shaped intake port at a position near the upper wall of the helically-shaped intake port.
Claims34
A multi-cylinder internal combustion engine, each cylinder having a helically-shaped intake port which comprises a helical portion having an outlet open end, an intake valve arranged in said outlet open end, and an inlet passage portion tangentially connected to said helical portion and having an inlet open end, said inlet passage portion being defined by an upper wall, a bottom wall, a first side wall arranged at a position near an axis of said intake valve, and a second side wall arranged at a position remote from the axis of said intake valve, said engine comprising:
- at least one intake passage common to at least two cylinders and having at least two outlets, each being connected to the inlet open end of a respective one of said intake ports;
- fuel supply means arranged in said intake passage;
- valve means arranged in said intake passage and opened in accordance with an increase in the level of the load of said engine;
- means for supplying an auxiliary flow of gas to each intake port when the respective intake valve is open during the intake stroke, said means including a common connecting passage and at least two branch connecting passages, each being connected to said common connecting passage and having an opening which opens into a respective one of said intake ports in the vicinity of the upper wall of said respective intake port at a position located downstream of said valve means, and further, wherein the first side wall of each of said inlet passage portions has an inclined wall portion which faces downwardly, and the opening of each respective branch connecting passage is directed towards said inclined wall portion, such that when each intake valve is opened, a flow of gas from the opening of the respective branch connecting passage is directed by said inclined wall portion and said upper wall towards the second side wall and thence along the circumference of said helical portion to develop a strong swirl motion prior to passing through said outlet open end into the cylinder.
A multi-cylinder internal combustion engine having a plurality of cylinders, each having a helically-shaped intake port which comprises a helical portion having an outlet open end, an intake valve arranged in said outlet open end, and an inlet passage portion tangentially connected to said helical portion and having an inlet open end, said inlet passage portion being defined by an upper wall, a bottom wall, a first side wall arranged at a position near an axis of said intake valve, and a second side wall arranged at a position remote from the axis of said intake valve, said engine comprising:
- at least one intake passage common to at least two cylinders and including an inlet passage, a collecting portion having an inlet connected to the inlet passage and an outlet, and at least two branch intake passages branched off from the outlet of said collecting portion, each of said branch intake passages being connected to the inlet open end of a respective one of said intake ports;
- fuel supply means arranged in said intake passage;
- a throttle valve arranged in said inlet passage and opened in accordance with increasing load level of said engine;
- a common connecting passage;
- an air passage connecting said common connecting passage to said inlet passage at a location upstream of said throttle valve;
- a flow control device arranged in said air passage;
- and
- at least two branch connecting passages, each being connected to said common connecting passage and having an opening which opens into a respective one of said intake ports in the vicinity of the upper wall of said intake port, and further, wherein the first side wall of each of said passage portions has an inclined wall portion which faces downwardly, and the opening of each respective branch connecting passage is directed towards said inclined wall portion, such that when each intake valve is opened, a flow of gas from the opening of the respective branch connecting passage is directed by said inclined wall portion and said upper wall towards the second side wall and thence along the circumference of said helical portion to develop a strong swirl motion prior to passing through said outlet open end into the cylinder.
Dependencies are inferred from the claim text.