Method and systems for a generator in a plug-in hybrid electric vehicle

Patent metadata

Field	Value
Publication number	US-10821965-B2
Application number	US-201816146986-A
Country	US
Kind code	B2
Filing date	Sep 28, 2018
Priority date	Oct 9, 2017
Publication date	Nov 3, 2020
Grant date	Nov 3, 2020

Abstract

Methods and systems are provided for operating a high voltage generator coupled to a plug-in hybrid vehicle driven by a reciprocating piston engine. In one example, a method may include, predicting variations in output torque from the reciprocating piston engine and adjusting the driving torque required for the high voltage electric generator based upon the predicted torque variations.

First claim

The invention claimed is:

1. A system for a range extended plug-in hybrid electric vehicle, comprising:
a reciprocating piston engine, a drivetrain including a transmission driving at least one road wheel, a low voltage electrical system including a low voltage battery and an electronic controller, a high voltage electrical system including a high voltage electrical generator driven via a coupling with the reciprocating piston engine, a high voltage battery to store electrical energy input from an external main supply, a high voltage electric traction motor electrically connected to the high voltage battery and arranged to selectively drive the transmission, and a controller with computer readable instructions stored on non-transitory memory to:
during operation of the reciprocating piston engine, use a model to produce an output of expected torque variations from the reciprocating piston engine based upon one or more inputs indicative of the operation of the reciprocating piston engine and use the output of expected torque variations from the model to control the operation of the high voltage electrical generator;
wherein controlling operation of the high voltage electrical generator includes phase shifting a torque driving the high voltage electrical generator with respect to the expected torque variations of the reciprocating piston engine to lead the expected torque variations of the reciprocating piston engine.

2. The system of claim 1 , wherein controlling operation of the high voltage electrical generator includes varying the torque driving the high voltage electrical generator to compensate for the expected torque variations.

3. The system of claim 2 , wherein varying the torque driving the high voltage electrical generator includes varying a magnitude of current flowing through stationary exciter field coils of the high voltage electrical generator.

4. The system of claim 3 , wherein the controller includes further instructions to: provide the output of the expected torque variations from the model to a dynamic system model of a drive path from the reciprocating piston engine to the high voltage electrical generator, and use an output from the dynamic system model to vary a magnitude of current flowing through the stationary exciter field coils.

5. The system of claim 1 , wherein the one or more inputs indicative of the operation of the reciprocating piston engine include each of a rotational speed of a crankshaft of the reciprocating piston engine, a rotational position of the crankshaft, a torque demand to be met by the reciprocating piston engine, a number of cylinders of the reciprocating piston engine, and a combustion timing of the reciprocating piston engine.

6. The system of claim 5 , wherein the coupling comprises a flywheel of a predefined inertia fastened to one end of the crankshaft of the reciprocating piston engine, a drive plate of lower inertia relative to the predefined inertia of the flywheel driveably connected to an input shaft of the high voltage electrical generator, and a rotary drive driveably connecting the flywheel to the drive plate.

7. A method, comprising:
during operation of an engine coupled to a hybrid vehicle, adjusting an input to a generator generating electric power to drive a traction motor based on expected torque variations from the engine; and
phase shifting an electrical signal delivered to drive the generator relative to an estimated torque output of the engine.

8. The method of claim 7 , wherein adjusting the input to the generator includes increasing or decreasing a magnitude of a field current through stationary exciter field coils of an exciter alternator of the generator based on the expected torque variations.

9. The method of claim 8 , wherein the magnitude of the field current is estimated via a dynamic system model, the magnitude further based on each of an inertia and a torsional stiffness of a drive plate coupling the engine to the generator.

10. The method of claim 9 , wherein the expected torque variations are modelled based on one or more of a rotational speed of a crankshaft coupled to the engine, a rotational position of the crankshaft, engine load, a number of cylinders coupled to the engine, and a combustion timing of the cylinders.

11. The method of claim 7 , wherein the phase shifting includes positive phase shifting the electrical signal delivered to drive the generator relative to the estimated torque output of the engine.

12. The method of claim 7 , wherein the generator converts engine torque to electrical energy transmitted to the traction motor driving the vehicle.

13. The method of claim 10 , wherein the generator is coupled to the crankshaft via each of a flywheel, a rotary drive, a drive plate, and an input shaft, the drive plate having a lower inertia relative to the flywheel.

14. A method for a plug-in hybrid electric vehicle, comprising:
during a first condition, operating the vehicle via an electric motor powered by electrical energy generated from engine torque via a generator, an electrical input to the generator adjusted based on an estimated variation in engine torque, wherein the electrical input to the generator is positive phase shifted relative to an estimated engine torque; and
during a second condition, operating the vehicle via the electric motor powered by a battery while maintaining an engine and the generator inactive.

15. The method of claim 14 , wherein the first condition includes a lower than threshold state of charge of the battery and the second condition includes a higher than threshold state of charge of the battery, the threshold state of charge based on operator torque demand, wherein a shaft of the electric motor is not mechanically coupled to or driven by a shaft of the generator, and wherein the only power transfer between the electric motor and the generator is through an electrical power system.

16. The method of claim 14 , wherein the electrical input to the generator is adjusted by adjusting a magnitude of a field current through stationary exciter field coils of an exciter alternator of the generator.

17. The method of claim 16 , wherein the magnitude of the field current is based on each of estimated variations in torque generated by the engine, inertia of a drive plate coupling the engine to the generator, and a torsional stiffness of the drive plate.

18. The method of claim 16 , wherein the estimated variations in torque are modelled based on one or more of a rotational speed of a crankshaft coupled to the engine, a rotational position of the crankshaft, engine load, a number of cylinders coupled to the engine, and a combustion timing of the cylinders.

Assignees

• Ford Global Tech Llc

Inventors

• Wilkinson Toby-Jon
• Foster James
• Brittle Peter

Classifications

• Y02T10/62

  Hybrid vehicles · CPC title

• F16F15/133

  using springs as elastic members, e.g. metallic springs · CPC title

• B60W2050/0012

  Feedforward or open loop systems · CPC title

• B60W2030/206

  related or induced by the engine · CPC title

• F16F15/002

  characterised by the control method or circuitry (control of mechanical oscillations per se G05D19/00) · CPC title