Engine speed control via alternator load shedding

Patent metadata

Field	Value
Publication number	US-9628011-B2
Application number	US-201514614881-A
Country	US
Kind code	B2
Filing date	Feb 5, 2015
Priority date	Feb 5, 2015
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

Method and systems are provided for adjusting an engine load exerted on a vehicle engine by an alternator mechanically coupled to said engine. In one example, a method may include when decelerating a vehicle driven by an engine, recharging a battery by an alternator driven by said engine, and during engine idle speed control, when engine speed is less than desired, in a first mode reducing electrical power to selected devices, and in a second mode offsetting a set point of desired engine ignition timing to a new set point when engine speed is higher than desired.

First claim

The invention claimed is:

1. A method, comprising:
when decelerating a vehicle driven by an engine, recharging a battery by an alternator driven by said engine and increasing alternator torque during said vehicle deceleration to provide an additional braking force to said vehicle; and
during engine idle speed control, when engine speed is less than desired, in a first mode reducing electrical power supplied to selected devices from the alternator, and in a second mode offsetting a set point of desired engine ignition timing to a new set point when engine speed is higher than desired.

2. The method recited in claim 1 wherein said idle speed control commences when said vehicle slows to a preselected speed.

3. The method recited in claim 1 wherein increasing alternator torque comprises increasing voltage or current applied to a rotor field coil of said alternator and increasing current flow to the battery when alternator torque is increased.

4. The method recited in claim 1 further comprising decreasing alternator torque when reducing electrical power to selected devices in the first mode, and wherein the decreasing of alternator torque comprises decreasing voltage or current applied to a rotor field coil of said alternator.

5. The method recited in claim 1 further comprising when engine speed is greater than desired, in the first mode, retarding the ignition timing from the desired engine ignition timing, and, in the second mode, retarding ignition timing further from the new set point.

6. The method recited in claim 1 wherein said selected devices comprise electrical devices which if disabled or supplied with reduced electrical power would not be perceptible by an operator, said devices including one or more of the following: coolant fans, pumps, heaters, air conditioners, fans, radio, lights, heated rear window, heated steering wheel, heated shift knob, and heated front window.

7. The method recited in claim 1 further comprising moving a throttle coupled to said engine for controlling airflow inducted into said engine toward a fully open position when said engine speed is less than desired or toward a fully closed position when said engine speed is higher than desired.

8. A method, comprising:
controlling idle speed of an engine coupled to an alternator which supplies electrical power to various electrical devices in a vehicle driven by said engine;
a first mode of said engine idle speed control which is active when reducing or shutting off electrical power applied to selected ones of said electrical devices would be perceived by an operator of the vehicle;
during said first engine idle speed control mode, offsetting a steady state ignition timing value of said engine in a retarded direction to an offset retarded value, and when engine speed is less than desired, advancing ignition timing from said offset retarded value, and when said engine speed is greater than desired, retarding said ignition timing from said offset retarded value;
a second mode of said engine idle speed control which is active when reducing or shutting off electrical power applied to said selected ones of said electrical devices would not be perceived by an operator of the vehicle; and
during said second idle speed control mode, removing said offset retarded value, and disabling or reducing electrical power to said selected ones of said electrical devices when said engine speed is less than desired, and retarding said ignition timing from said steady state ignition timing value when engine speed is higher than desired.

9. The method recited in claim 8 further comprising regulating field current in said alternator to control torque of said alternator and current output by said alternator.

10. The method recited in claim 9 wherein said field current regulation includes regulating said field current to decrease alternator torque and increase engine torque after said shutting off electrical power applied to said selected ones of said electrical devices in the second engine idle speed control mode.

11. The method recited in claim 8 further comprising moving a throttle coupled to said engine for controlling airflow inducted into said engine toward a fully open position when said engine speed is less than desired and moving said throttle toward a closed position when said engine speed is higher than desired.

12. The method recited in claim 8 further comprising charging a battery of said vehicle via current provided by said alternator of said vehicle when a charge state of the battery drops below a threshold, but reducing the current supplied to said battery in the first engine idle speed control mode when the engine speed is less than desired.

13. The method recited in claim 12 wherein the reducing the current supplied to the battery comprises reducing alternator torque by reducing voltage or current applied to a rotor field coil of the alternator.

14. A method, comprising:
when decelerating a vehicle driven by an engine, recharging a battery by an alternator driven by said engine;
commencing idle speed control of said engine when said vehicle has slowed to a preselected speed;
enabling said battery charging at idle when a charge of the battery drops below a threshold;
during a first mode of operation, offsetting nominal ignition timing of said engine in a retarded direction to an offset nominal value, and when engine speed is less than desired, advancing ignition timing from said offset nominal value, and when said engine speed is greater than desired, retarding said ignition timing from said offset nominal value; and
during a second mode of operation, when reducing electrical power applied to selected electrical devices would not be perceptible to an operator of said vehicle, shutting off said electrical power applied to said selected electrical devices when engine speed is less than desired and retarding ignition timing of said engine from said nominal ignition timing when said engine speed is greater than desired.

15. The method recited in claim 14 wherein said nominal ignition timing corresponds to a steady state ignition timing and an offset ignition timing is set to allow said ignition timing advance without inducing ignition knock in said engine.

16. The method recited in claim 14 further comprising voltage regulation of voltage provided by said alternator, said voltage regulation causing a reduction in torque of said alternator and related increase in torque provided by said engine in response to said shutting off electrical power applied to said selected electrical devices.

17. The method recited in claim 14 further comprising increasing alternator torque during said vehicle deceleration to provide an additional braking force to said vehicle, wherein increasing alternator torque comprises increasing voltage or current applied to a rotor winding of said alternator.

18. The method of claim 14 further comprising supplying electrical power to the selected electrical devices from the battery and decreasing alternator torque.

19. The method of claim 8 wherein a position of a brake pedal is used as a factor to determine desired engine speed.

20. The method of claim 1 wherein an amount of charge stored on the battery is used to determine whether to increase alternator torque.

Assignees

• Ford Global Tech Llc

Inventors

• Demarco John Anthony
• Hickey John Curtis
• Pursifull Ross Dykstra
• Ulrey Joseph Norman

Classifications

• F02P5/1504

  with particular means during a transient phase, e.g. acceleration, deceleration, gear change (during starting F02P5/1506) · CPC title

• F02D41/16 Primary

  for idling · CPC title

• H02P9/48 Primary

  Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle (H02P9/04 - H02P9/46 take precedence) · CPC title

• H02P9/04

  Control effected upon non-electric prime mover and dependent upon electric output value of the generator · CPC title

• F02D37/02 Primary

  one of the functions being ignition · CPC title