Method of controlling engine stop-start operation for heavy-duty hybrid-electric and hybrid-hydraulic vehicles
View Patent ↗A start-stop or idle-stop method for a heavy-duty hybrid vehicle that turns off the fuel supply while maintaining the crankshaft rotation of the internal combustion engine when the vehicle stops or, optionally, when the vehicle travels downhill, travels in a noise sensitive location, travels in an exhaust emissions sensitive location, or operates in an emergency situation. The stop-start or idle-stop method automatically turns on the engine fuel supply to restart combustion when the vehicle starts accelerating, is no longer traveling downhill, is no longer traveling in a noise sensitive or exhaust sensitive location, is no longer in an emergency situation, or has dropped below the minimum energy storage restart level.
1. A method for efficiently controlling an engine of a heavy-duty hybrid-electric vehicle of at least 10,000 pounds Gross Vehicle Weight Rating (GVWR), the heavy-duty hybrid-electric vehicle having a generator, an inverter, a propulsion motor, a first energy storage, and a control computer, the method comprising:
enabling a function comprising at least one of a Stop-Start and an Idle-Stop function;
determining a first vehicle propulsion power requirement associated with an emergency situation of the heavy-duty hybrid-electric vehicle;
determining a first energy storage first State Of Charge;
when the energy storage first State Of Charge is above an energy storage first State Of Charge minimum threshold, turning off the engine if the first vehicle propulsion requirement is below a first vehicle propulsion requirement minimum threshold;
when the energy storage first State Of Charge is below an energy storage first State Of Charge minimum threshold, turning off the engine if the first vehicle propulsion requirement is below a first vehicle propulsion requirement minimum threshold; and
commanding the generator to spin the engine to drive at least one Power Take-Off accessory.
2. The method of claim 1 , further comprising
determining whether an override is on; and,
wherein the turning off the engine if the first vehicle propulsion requirement is below a first vehicle propulsion requirement minimum threshold when the energy storage first State Of Charge is below an energy storage first State Of Charge minimum threshold, comprises , turning off the engine if the first vehicle propulsion requirement is below a first vehicle propulsion requirement minimum threshold when the energy storage first State Of Charge is below an energy storage first State Of Charge minimum threshold and the override is on.
3. The method of claim 2 , further comprising activating a Warning Indicator if the energy storage first State Of Charge is below an energy storage first State Of Charge minimum threshold, and the override is on.
4. The method of claim 1 , wherein the turning off the engine comprises turning off a fuel supply to the engine.
5. The method of claim 4 , wherein the turning off the engine further comprises turning off an ignition to the engine.
6. The method of claim 5 , wherein the turning off the engine comprises turning off an emission control system.
7. The method of claim 1 , further comprising:
switching the generator to operate as a motor; and,
spinning the engine with the generator.
8. The method of claim 7 , wherein the spinning the engine with the generator comprises driving at least one Power Take-Off accessory.
9. The method of claim 7 , wherein the spinning the engine with the generator comprises electrically coupling the generator with a high voltage bus.
10. The method of claim 9 , wherein the electrically coupling the generator with the high voltage bus comprises electrically supplying power from at least one of the energy storage and a braking regeneration energy source.
11. The method of claim 1 , wherein the emergency situation of the heavy-duty hybrid-electric vehicle is determined from onboard sensors and a computer monitoring program.
12. The method of claim 1 , further comprising:
determining a second vehicle propulsion power requirement;
determining an energy storage second State Of Charge;
restarting the engine if the second vehicle propulsion requirement is above a second vehicle propulsion requirement minimum threshold; and,
restarting the engine if the energy storage second State Of Charge is below an energy storage second State Of Charge minimum threshold, and the override is off.
13. The method of claim 12 , wherein, to limit oscillations, at least one of:
the first vehicle propulsion requirement minimum threshold is significantly below the second vehicle propulsion requirement minimum threshold, and,
the energy storage second State Of Charge minimum threshold is significantly below the energy storage first State Of Charge minimum threshold.
14. The method of claim 12 , wherein the energy storage second State Of Charge is below the energy storage second State Of Charge minimum threshold if the energy storage second State Of Charge is less than a minimum operating threshold to sustain an accessory power requirement during at least one of a Stop-Start cycle and a Idle-Stop cycle.
15. The method of claim 12 , wherein the restarting the engine comprises:
switching the generator to operate as a motor; and,
spinning the engine with the generator.
16. The method of claim 1 , wherein the energy storage comprises a high voltage energy storage.
17. The method of claim 16 , wherein the high voltage energy storage comprises one or more ultracapacitors.
18. The method of claim 1 , wherein the control computer is configured to communicate over a control area network (CAN).
19. The method of claim 1 , wherein the generator is nominally rated at 650 V with at least 20 kW of power.
20. The method of claim 1 , wherein the propulsion motor is nominally rated at 650 V with at least 15 kW of power.
21. The method of claim 1 , wherein the inverter comprises an IGBT high power switching device nominally rated at 650 V with multiple phase.
22. The method of claim 1 , wherein the heavy-duty hybrid-electric vehicle is a configured as a series hybrid drive.