Engine spin-up control with natural torque smoothing
View Patent ↗A hybrid vehicle includes an engine having at least one cylinder and an electric machine that drives the engine during a start-up period. A control module monitors a rotational speed of the engine and regulates torque generated by the electric machine based on the rotational speed during the start-up period and a maximum discharge power available to power the electric machine.
1. A hybrid vehicle, comprising:
an engine having at least one cylinder;
an electric machine that drives said engine during a start-up period;
a control module that monitors a rotational speed of said engine and that regulates torque generated by said electric machine based on said rotational speed and a maximum discharge power available to power said electric machine during said start-up period; and
a driver input device, wherein said control module determines said maximum discharge power based on said driver input device.
2. The hybrid vehicle of claim 1 wherein said control module determines a start-up schedule based on said driver input device and determines said maximum power based on said start-up schedule.
3. The hybrid vehicle of claim 2 wherein said start-up schedule includes a torque command and said maximum discharge power.
4. The hybrid vehicle of claim 3 wherein said start-up schedule further includes a torque slew rate command.
5. The hybrid vehicle of claim 1 wherein said driver input device includes an accelerator pedal.
6. The hybrid vehicle of claim 5 wherein said control module determines a start-up schedule based on a position of said accelerator pedal.
7. The hybrid vehicle of claim 1 wherein said driver input device includes a brake pedal.
8. The hybrid vehicle of claim 7 wherein said control module determines a start-up schedule based on a position of said brake pedal.
9. The hybrid vehicle of claim 1 wherein said control module determines said start-up schedule based on a pressure within a brake system.
10. The hybrid vehicle of claim 1 wherein said control module regulates said rotational speed based upon a desired idle speed when said rotational speed achieves a speed threshold.
11. A method of launching a hybrid vehicle from rest, comprising:
monitoring a driver input from a drive input device;
determining a start-up schedule based on said driver input;
determining a maximum discharge power from said start-up schedule; and
regulating a torque generated by an electric machine to drive an engine during a start-up period based on said maximum discharge power and a rotational speed of said engine.
12. The method of claim 11 wherein said driver input device includes an accelerator pedal and said start-up schedule is determined based on a position of said accelerator pedal.
13. The method of claim 11 wherein said driver input device includes a brake pedal and said start-up schedule is determined based on a position of said brake pedal.
14. The method of claim 13 wherein said start-up schedule is determined based on a pressure within a brake system.
15. The method of claim 11 further comprising regulating said rotational speed based upon a desired idle speed when said rotational speed achieves a speed threshold.
16. The method of claim 11 wherein said maximum discharge power is determined from said start-up schedule based on a rotational speed of said electric machine.
17. The method of claim 16 wherein said maximum discharge power is further determined from said start-up schedule based on a rate of change of said rotational speed.
18. The method of claim 11 further comprising activating a cylinder of said engine subsequent to said engine achieving an idle speed.
19. A method of spinning up an engine of a hybrid vehicle to an idle speed during a start-up period, comprising:
determining a start-up schedule including a maximum discharge power;
regulating a torque generated by an electric machine to drive said engine during said start-up period based on said maximum discharge power and a rotational speed of said engine;
monitoring a driver input from a driver input device; and
determining said start-up schedule based on said driver input.
20. The method of claim 19 wherein said driver input device includes an accelerator pedal and said start-up schedule is determined based on a position of said accelerator pedal.
21. The method of claim 19 wherein said driver input device includes a brake pedal and said start-up schedule is determined based on a position of said brake pedal.
22. The method of claim 21 wherein said start-up schedule is determined based on a pressure within a brake system.
23. The method of claim 19 further comprising regulating said rotational speed based upon a desired idle speed profile when said rotational speed achieves a speed threshold.
24. The method of claim 19 wherein said maximum discharge power is determined from said start-up schedule based on a rotational speed of said electric machine.
25. The method of claim 24 wherein said maximum discharge power is further determined from said start-up schedule based on a rate of change of said rotational speed.
26. The method of claim 19 further comprising activating a cylinder of said engine subsequent to said engine achieving an idle speed.