Accessory drive system for an automotive engine

An accessory drive system for an automotive engine, comprising:

• a drive pulley attached to an output shaft of the engine;
• a flexible drive belt for connecting the drive pulley with a plurality of driven pulleys, with one driven pulley located upon each of a plurality of driven devices;
• and
• a tensioner for maintaining the drive belt in contact with each of said drive and driven pulleys, with said tensioner comprising an arm which is rotatably mounted to the engine and which has a wheel for contacting the drive belt, with the wheel being urged into contact with the drive belt by the arm, and with said tensioner further comprising a governor for controlling the rotational motion of the arm such that the arm will be freely able to rotate in the direction in which the tension in the drive belt is increased, with said governor resisting motion of the arm in the direction in which tension in the drive belt is decreased, wherein said governor comprises a hydraulic strut interposed between said tensioner arm and a mounting surface fixed to the engine adjacent the tensioner, such that linear motion of the strut accompanies rotational motion of the arm, with the strut having a connecting rod portion being able to move freely in the direction in which tension in the drive belt is increased, while resisting movement in the direction in which tension in the drive belt is decreased.