Starter device for combustion engine, particularly of motor vehicle

A starter device for a combustion engine of a motor vehicle, comprising:

• a rotary electrical machine comprising a drive member;
• a transmission member comprising a belt drivingly coupling the drive member of the rotary electrical machine with the combustion engine in order to start the combustion engine using the transmission member rotationally driven by the rotary electrical machine in a first direction;
• and
• a tensioner pressing against a length of the transmission member running between the rotary electrical machine and the combustion engine;
• the rotary electrical machine rotatable in a second direction opposite of the first direction in order to transition the tensioner from a stopped position into a position for beginning to start the combustion engine;
• the transition of the tensioner from the stopped position to the position for beginning to start being accompanied by lengthening of the length of transmission member and/or by increasing the tension in the length of transmission member.

A rotary electrical machine (11) forming a starter-alternator for a motor vehicle and arranged to start a combustion engine, the rotary electrical machine being linked with a control system for operating the rotation of the rotary electrical machine in a first direction during a starting stage in order to start the combustion engine and in a second direction opposite of the first direction during a preparation stage executed prior to the starting stage;

• the control system comprising an inverter and at least one switch (34;
• 35;
• 36) provided to selectively connect position sensors (31;
• 32;
• 33) of a rotor of the rotary electrical machine to arms (U;
• V;
• W) of the inverter.