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

Patent metadata

Field	Value
Publication number	US-2019106098-A1
Application number	US-201816146986-A
Country	US
Kind code	A1
Filing date	Sep 28, 2018
Priority date	Oct 9, 2017
Publication date	Apr 11, 2019
Grant date	—

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

1 . A system for a range extended plug-in hybrid electric vehicle comprises:
a reciprocating piston engine, a drivetrain including a transmission driving at least one road wheel, a low voltage electrical system including a low voltage electrical storage device 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 electrical storage device to store electrical energy input from an external mains supply, a high voltage electric traction motor electrically connected to the high voltage storage device 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 combustion 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 torque variations from the model to control the operation of the high voltage electrical generator.

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

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

4 . to 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 engine to the high voltage electrical generator, and use an output from the dynamic system model to vary the magnitude of current flowing through the stationary exciter field coils.

5 . The system of claim 3 , wherein the torque driving the high voltage electrical generator is phase shifted with respect to the expected torque variations of the reciprocating piston engine to lead the expected torque variations of the reciprocating piston engine.

6 . 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.

7 . The system of claim 6 , 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 resilient rotary drive driveably connecting the flywheel to the drive plate.

8 . 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.

9 . The method of claim 8 , 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 electric generator based on the expected torque variations.

10 . The method of claim 9 , 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 electric generator.

11 . The method of claim 10 , wherein the expected torque variations is 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 engine cylinders.

12 . The method of claim 8 , further comprising, positive phase shifting an electrical signal delivered to drive the generator relative to an estimated torque output of the engine.

13 . The method of claim 8 , wherein the generator converts engine torque to electrical energy transmitted to the traction motor driving the vehicle.

14 . The method of claim 11 , 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.

15 . 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; and during a second condition, operating the vehicle via the electric motor powered by a battery while maintaining the engine and the generator inactive.

16 . The method of claim 15 , 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 where the only power transfer between the electric motor and the generator is through an electrical power system.

17 . The method of claim 15 , 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 electric generator.

18 . The method of claim 17 , wherein the magnitude of the field current 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.

19 . The method of claim 17 , wherein the estimated variations in torque is 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 engine cylinders.

20 . The method of claim 15 , wherein the electrical input to the generator is positive phase shifted relative to an estimated engine torque.

Assignees

• Ford Global Tech Llc

Inventors

• Wilkinson Toby-Jon
• Foster James
• Brittle Peter

Classifications

• B60W2900/00

  Indexing codes relating to the purpose of, or problem solved of road vehicle drive control systems not otherwise provided for in groups B60W30/00 · CPC title

• B60W20/00

  Control systems specially adapted for hybrid vehicles {(hybrid vehicle design, B60K6/00; electric vehicles B60L)} · CPC title

• F16F15/002

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

• B60W10/30

  including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps · CPC title

• B60W2050/0039

  of the propulsion unit · CPC title