Hybrid vehicle propulsion systems and methods
A hybrid vehicle propulsion includes an engine and a first electric machine, where each is configured to selectively provide torque to propel the vehicle. The propulsion system also includes a second electric machine coupled to the engine to provide torque to start the engine from an inactive state. A high-voltage power source is configured to power both of the first electric machine and the second electric machine over a high-voltage bus. The propulsion system further includes a controller programmed to deactivate the engine and propel the vehicle using the first electric machine in response to the vehicle being driven at a steady-state speed for a predetermined duration of time. The controller is also programmed to restart the engine using the second electric machine powered by the high-voltage power source.
1. A method of operating a vehicle propulsion system comprising:
selectively operating at least one of a combustion engine and a first electric machine to provide a propulsion torque, the first electric machine being powered by a high-voltage power source;
deactivating the combustion engine in response to the vehicle being operated at a speed corresponding to a power draw less than a power threshold for a predetermined amount of time;
in response to a torque demand that is greater than a torque demand threshold, restarting the combustion engine using torque output from a second electric machine powered by the high voltage power source; and
powering at least one of the first electric machine and the second electric machine using a low-voltage power source in response to a fault condition associated with the high-voltage power source.
2. The method of claim 1 , further comprising:
operating the second electric machine as a generator in response to a fault condition associated with the first electric machine.
3. The method of claim 1 , further comprising:
operating the first electric machine as a generator to provide power to the high-voltage power source in response to a vehicle coast condition.
4. The method of claim 1 , further comprising:
deactivating the combustion engine in response to the vehicle being at a standstill for a predetermined amount of time.
5. The method of claim 1 , further comprising:
generating a state of health prognosis signal for at least one of the first electric machine, the second electric machine, and the high-voltage power source, and transmitting the prognosis signal to an off-board processor.
6. The method of claim 1 , further comprising:
powering at least one vehicle accessory component using torque output from the first electric machine while the engine is deactivated.
7. The method of claim 1 , further comprising:
receiving a signal indicative of at least one available parking space;
providing a user interface to inform a user of the at least one available parking space;
generating at least one proximity signal indicative of at least one object in a vicinity of the vehicle; and
in response to a user prompt, automatically operating the first electric machine to propel the vehicle to the target parking space.
8. A method of operating a vehicle propulsion system comprising:
selectively operating at least one of a combustion engine and a first electric machine to provide a propulsion torque, the first electric machine being powered by a high-voltage power source;
deactivating the combustion engine in response to the vehicle being operated at a speed corresponding to a power draw less than a power threshold for a predetermined amount of time;
in response to a torque demand that is greater than a torque demand threshold, restarting the combustion engine using torque output from a second electric machine powered by the high voltage power source; and
operating the second electric machine as a generator in response to a fault condition associated with the first electric machine.
9. The method of claim 8 , further comprising:
operating the first electric machine as a generator to provide power to the high-voltage power source in response to a vehicle coast condition.
10. The method of claim 8 , further comprising:
deactivating the combustion engine in response to the vehicle being at a standstill for a predetermined amount of time; and
powering at least one vehicle accessory component using torque output from the first electric machine while the engine is deactivated.
11. The method of claim 8 , further comprising:
generating a state of health prognosis signal for at least one of the first electric machine, the second electric machine, and the high-voltage power source, and transmitting the prognosis signal to an off-board processor.
12. The method of claim 8 , further comprising:
receiving a signal indicative of at least one available parking space;
providing a user interface to inform a user of the at least one available parking space;
generating at least one proximity signal indicative of at least one object in a vicinity of the vehicle; and
in response to a user prompt, automatically operating the first electric machine to propel the vehicle to the target parking space.
13. A propulsion system for a vehicle, the propulsion system comprising:
a combustion engine and a first electric machine each configured to selectively provide torque to propel the vehicle;
a second electric machine coupled to the engine to selectively provide torque;
a high-voltage power source configured to selectively power the first electric machine and the second electric machine;
a low-voltage power source configured to selectively power the first electric machine and the second electric machine; and
a controller programmed to:
selectively operate at least one of the combustion engine and the first electric machine to provide a propulsion torque, the first electric machine being powered by the high-voltage power source;
deactivate the combustion engine in response to the vehicle being operated at a speed corresponding to a power draw less than a power threshold for a predetermined amount of time;
in response to a torque demand that is greater than a torque demand threshold, restart the combustion engine using torque output from the second electric machine powered by the high voltage power source; and
power at least one of the first electric machine and the second electric machine using the low-voltage power source in response to a fault condition associated with the high-voltage power source.
14. The propulsion system of claim 13 , wherein the controller is programmed to:
operate the second electric machine as a generator in response to a fault condition associated with the first electric machine.
15. The propulsion system of claim 13 , wherein the controller is programmed to:
operate the first electric machine as a generator to provide power to the high-voltage power source in response to a vehicle coast condition.
16. The propulsion system of claim 13 , wherein the controller is programmed to:
deactivate the combustion engine in response to the vehicle being at a standstill for a predetermined amount of time.
17. The propulsion system of claim 13 , wherein the controller is programmed to:
generate a state of health prognosis signal for at least one of the first electric machine, the second electric machine, and the high-voltage power source, and transmit the prognosis signal to an off-board processor.
18. The propulsion system of claim 13 , further comprising:
at least one vehicle accessory component operatively connected to the first electric machine; and
wherein the controller is programmed to power t h e at least one vehicle accessory component using torque output from the first electric machine while the engine is deactivated.
19. The propulsion system of claim 13 , wherein the controller is programmed to:
receive a signal indicative of at least one available parking space;
provide a user interface to inform a user of the at least one available parking space;
generate at least one proximity signal indicative of at least one object in a vicinity of the vehicle; and
in response to a user prompt, automatically operate the first electric machine to propel the vehicle to the target parking space.