Apparatus and method for controlling an electrical starter of an internal combustion engine

A method for controlling an electrical starter motor for cranking a cranking mechanism of an internal combustion engine in order to start the internal combustion engine, said method comprising the steps of:

• a) providing circuit means for making an electrical connection between a voltage source and the electrical starter motor, with which the electrical starter motor is coupled with a cranking gear of the internal combustion engine by means of a shiftable transmission when the circuit means is energized;
• and
• b) controlling at least one of a voltage, a current and an on-time of the electrical starter motor in a stepwise manner in a two-stage control process by means of an electronic control unit connected between the voltage source and the electrical starter motor, said two-stage control process including a first stage in which said starter motor is operated at a rotation speed that is reduced in comparison to full rotation speed of said starter motor, so that wear is reduced in comparison to that experienced during a single-stage control process in which said starter motor is operated at the full rotation speed prior to being coupled with said cranking gear;
• wherein the electrical starter motor has a starter pinion engaged with the cranking gear in a first stage of the two-stage control process and the starter motor is rotated at full speed in a second stage of the two-stage control process;
• and
• wherein the circuit means includes a starter switch (24) and the electronic control unit provides said voltage of the electrical starter motor, when the starter switch is closed, and said voltage is less than a nominal voltage of the electrical starter motor until the starter pinion engages with the cranking gear.

A method for controlling an electrical starter motor for cranking a cranking mechanism of an internal combustion engine in order to start the internal combustion engine, said method comprising the steps of:

• a) providing circuit means for making an electrical connection between a voltage source and the electrical starter motor, in which the electrical starter motor is coupled with a cranking gear of the internal combustion engine by means of a shiftable transmission when the circuit means is energized;
• b) controlling at least one of a voltage, a current and an on-time of the electrical starter motor in a stepwise manner in a two-stage control process by means of an electronic control unit connected between the voltage source and the electrical starter motor;
• and
• c) reducing a maximum allowed on-time of the electrical starter motor according to a temperature measured at the electrical starter motor.