Systems and methods for tensioning a belt of a belt drive of an internal combustion engine

A method for an engine system comprising:

• during an engine stop:
• pulsing a starter motor to relax a belt of a belt drive around a tensioner pulley of the belt drive and induce extension of a tensioner spring
• wherein the pulsing the starter motor comprises repeatedly switching an amount of power provided to the starter at a threshold frequency
• wherein the threshold frequency is the resonant frequency of the belt drive.

A method for tensioning a belt of a belt drive of an internal combustion engine not in operation and having a crankshaft, in addition to the belt as a traction means a first driving wheel arranged on the crankshaft and a third wheel arranged on a shaft of a starter assigned to the belt drive, wherein the belt is guided around the driving first wheel and the third wheel, and a movable tensioning means assigned to an active tensioner is provided, which engages in the belt under application of force by a spring, forming a contact zone, and applies tensile forces to the belt along its longitudinal axis for tensioning, comprising:

• controlling the active tensioner such that a compression of the spring is at least countered, so that a movement of the tensioning means under the load of the belt is at least hindered;
• and then exciting the belt to vibration in the contact zone by use of the starter so that the tensioning means, exposed to the force of the spring, is moved further in the direction of the belt under expansion of the spring, whereby the belt is tensioned
• wherein the starter can rotate in a first rotation direction and in an opposite second rotation direction, the second rotation direction oriented opposite the direction of rotation of the crankshaft of the powered internal combustion engine,
• in a first step, applying a pre-definable opposing torque is to the belt drive to relax the belt in the contact zone, wherein this pre-definable opposing torque acts in the second rotation direction and is selected smaller than a break-free moment at which the crankshaft is set in rotation;
• and
• in a second step, applying a pre-definable torque of the same direction is applied to the belt drive in order to tension the belt in the contact zone, wherein this pre-definable torque of the same direction acts in the first rotation direction and is selected smaller than a break-free moment at which the crankshaft is set in rotation, and wherein one or more of the first step and the second step are repeated with a frequency which corresponds to a resonant frequency of the belt drive, the first step and second step are repeated until a pre-definable minimum tension is achieved in the belt drive, and the first step and second step are repeated until a pre-definable time interval has been exceeded.