Internal combustion engine port design layout for enhanced in-cylinder swirl generation

An internal combustion engine including a pair of adjacent cylinders, each one of said pair of adjacent cylinders comprising:

• a piston;
• a first intake valve;
• a second intake valve;
• a primary port associated with said first intake valve;
• and
• a secondary port associated with said second intake valve;
• each of said ports being configured to provide a predominant direction of airflow therethrough during engine operation when viewed from above said cylinders, said ports being oriented to provide respective in-cylinder air-swirl of opposite direction in each one of said pair of adjacent cylinders during an intake stroke of a respective piston;
• wherein the respective ports associated with each one of said pair of adjacent cylinders are configured so that an angle of intersection between the predominant direction of airflow through the respective primary port and the predominant direction of airflow through the respective secondary port is any angle in the range of between 15 degrees and 35 degrees, including all angles and ranges of angles therebetween, when viewed from above said cylinder.

Method for causing an increase in swirl during a respective air-intake stroke in each one of a pair of adjacent cylinders present on an internal combustion engine, each one of the pair of adjacent cylinders having two intake ports and corresponding intake port runners, the method comprising:

• configuring one of said respective intake ports of each one of the pair of adjacent cylinders as a direct port;
• configuring the other of said respective intake ports of each one of the pair of adjacent cylinders as a tangential port;
• arranging all of said respective intake ports so that the direction of swirl in one of the pair of adjacent cylinders is opposite to the direction of swirl in the other of the pair of adjacent cylinders;
• wherein arranging all of said respective intake ports comprises configuring the respective runners in each one of the pair of adjacent cylinders so that the predominant direction of airflow through one of the respective intake ports of a respective one of the pair of adjacent cylinders intersects the predominant direction of airflow through the other of the respective intake ports of the respective one of the pair of adjacent cylinders at any angle between 10 degrees and 45 degrees, including all angles and ranges of angles therebetween.