Method and device for controlling the drive train of a motor vehicle

A method for controlling the drive train of a motor vehicle having at least a drive unit and a transmission whose rpm ratio (u) can be adjusted, the drive unit having an adjustable output torque (md.sub.-- ma) and an output rpm (n.sub.-- mot) and the transmission having an output torque (md.sub.-- ga) and being arranged between the drive unit and the wheels of the motor vehicle;

• a desired value (md.sub.-- ga.sub.-- des) being pregiven for the transmission output torque, especially in dependence upon the detected position of an accelerator pedal actuable by the driver of the motor vehicle;
• and, different operating points (x.sub.i) of the drive train being characterized by at least different output torques (md.sub.-- ma.sub.i) of the drive unit and rpm ratios (u.sub.i) and/or different output rpms (n.sub.-- mot.sub.i) of the drive unit;
• the method comprising performing the following steps during driving operation of said motor vehicle:
• determining at least the following as evaluation quantities:
• a first value (G.sub.torque) which represents the reserve of the transmission output torque;
• and/or
• a second value (G.sub.eta), which represents the total efficiency of the drive train of the vehicle;
• and/or
• a third value (L.sub.emission,i) which represents the emission performance of different toxic components (i);
• and/or
• a fourth value (L.sub.noise) which represents the sound emission;
• determining a set of said evaluation quantities (G.sub.torque, G.sub.eta, L.sub.emission,i, L.sub.noise) for possible ones of said operating points (x.sub.i);
• selecting one of said possible ones of said operating points (x.sub.i) as optimal operating point (x.sub.opt) by utilizing an optimization method based on said detected evaluation quantities;
• and,
• adjusting the transmission ratio (u) of said drive unit to a transmission ratio (u.sub.opt) corresponding to the selected operating point (x.sub.opt) and/or adjusting the output rpm (n.sub.-- mot) of said drive unit corresponding to the selected operating point (x.sub.opt).

An arrangement for controlling the drive train of a motor vehicle having at least a drive unit and a transmission whose rpm ratio (u) can be adjusted, the drive unit having an adjustable output torque (md.sub.-- ma) and an output rpm (n.sub.-- mot) and the transmission having an output torque (md.sub.-- ga) and being arranged between the drive unit and the wheels of the motor vehicle;

• wherein different operating points (x.sub.i) of the drive train are characterized by at least different output torques (md.sub.-- ma.sub.i) of the drive unit and rpm ratios (u.sub.i) and/or different output rpms (n.sub.-- mot.sub.i) of the drive unit;
• the arrangement comprising means which, during driving operation of said motor vehicle, is adapted to:
• determine a set of evaluation quantities (G.sub.torque, G.sub.eta, L.sub.emission,i, L.sub.noise) for possible operating points (x.sub.i);
• utilize an optimization method to logically couple said evaluation quantities (G.sub.torque, G.sub.eta, L.sub.emission,i, L.sub.noise) belonging to one of said sets to form a result (F) and applying that one of said operating points (x.sub.i) at which the result (F) of the logical coupling assumes an extreme value to select one of the possible operating points (x.sub.i) as an optimal operating point (x.sub.opt);
• and,
• adjust the transmission ratio (u) of said drive unit to a transmission ratio (u.sub.opt) corresponding to the selected operating point (x.sub.opt) and/or adjust the output rpm (n.sub.-- mot) of said drive unit corresponding to the selected operating point (x.sub.opt).

An arrangement for controlling the drive train of a motor vehicle having at least a drive unit and a transmission whose rpm ratio (u) can be adjusted, the drive unit having an adjustable output torque (md.sub.-- ma) and an output rpm (n.sub.-- mot) and the transmission having an output torque (md.sub.-- ga) and being arranged between the drive unit and the wheels of the motor vehicle;

• a desired value (md.sub.-- ga.sub.-- des) being pregiven for the transmission output torque, especially in dependence upon the detected position of an accelerator pedal actuable by the driver of the motor vehicle;
• and, different operating points (x.sub.i) of the drive train being characterized by at least different output torques (md.sub.-- ma.sub.i) of the drive unit and rpm ratios (u.sub.i) and/or different output rpms (n.sub.-- mot.sub.i) of the drive unit;
• the arrangement comprising means which, during driving operation of said motor vehicle, is adapted to:
• determine at least the following as evaluation quantities:
• a first value (G.sub.torque) which represents the reserve of the transmission output torque;
• and/or
• a second value (G.sub.eta), which represents the total efficiency of the drive train of the vehicle;
• and/or
• a third value (L.sub.emission,i) which represents the emission performance of different toxic components (i);
• and/or
• a fourth value (L.sub.noise) which represents the sound emission;
• determine a set of said evaluation quantities (G.sub.torque, G.sub.eta, L.sub.emission,i, L.sub.noise) for each possible one of said operating points (x.sub.i);
• select one of said possible ones of said operating points (x.sub.i) as optimal operating point (x.sub.opt) by utilizing an optimization method based on said detected evaluation quantities;
• and,
• adjust the transmission ratio (u) of said drive unit to a transmission ratio (u.sub.opt) corresponding to the selected operating point (x.sub.opt) and/or adjust the output rpm (n.sub.-- mot) of said drive unit corresponding to the selected operating point (x.sub.opt).