Method for starting an internal combustion engine with the aid of a belt-driven starter generator

A device comprising:

• processing circuitry;
• and
• an interface to an engine-generator system that includes a starter generator to which an internal combustion engine is connected via a belt drive, the belt drive including (a) a belt pulley of the starter generator, (b) a belt pulley of the internal combustion engine, and (c) a belt connecting the belt pulleys in a torque-transmitting manner;
• wherein the processing circuitry is configured to generate, and output to the engine-generator system, control output that operates the starter generator such that its drive torque output M0 to the belt pulley of the starter generator is according to a drive torque curve by which, taking a gear ratio i of the belt drive into consideration, an output torque M1 generated temporarily on the belt pulley of the internal combustion engine exceeds the drive torque output M0 of the starter generator, such that M1>M0*i;
• wherein after the temporary exceedance, the output torque M1 generated on the belt pulley of the internal combustion engine decays over time from M1>M0*i to the drive torque output M0 of the starter generator taking the gear ratio i into consideration, such that M1 decays to M0*i, as the starter generator operates;
• wherein the drive torque curve according to which the starter generator operates is a linear drive torque curve having a torque gradient of at least Mmax/(0.5*T0), where Mmax is a peak torque value, and T0 is a period duration of a first natural frequency of the belt drive;
• wherein during the operating of the starter generator, a transmitted peak torque of the starter generator is less than a breakaway torque of a crankshaft of the internal combustion engine.

A non-transitory computer-readable medium on which are stored instructions that are executable by a processor, the instructions which, when executed by the processor, cause the processor to perform a method for starting an internal combustion engine using a starter generator to which the internal combustion engine is connected via a belt drive, the belt drive including a belt pulley of the starter generator, a belt pulley of the internal combustion engine, and a belt connecting the belt pulleys in a torque-transmitting manner, the method comprising:

• operating the starter generator such that its drive torque output M0 to the belt pulley of the starter generator is according to a drive torque curve by which, taking a gear ratio i of the belt drive into consideration, an output torque M1 generated temporarily on the belt pulley of the internal combustion engine exceeds the drive torque output M0 of the starter generator, such that M1>M0*i;
• and
• after the temporary exceedance, the output torque M1 generated on the belt pulley of the internal combustion engine decaying over time from M1>M0*i to the drive torque output M0 of the starter generator taking the gear ratio i into consideration, such that M1 decays to M0*i, as the starter generator operates;
• wherein the drive torque curve according to which the starter generator operates is a linear drive torque curve having a torque gradient of at least Mmax/(0.5*T0), where Mmax is a peak torque value, and T0 is a period duration of a first natural frequency of the belt drive;
• wherein during the operating of the starter generator, a transmitted peak torque of the starter generator is less than a breakaway torque of a crankshaft of the internal combustion engine.