Filtered battery current based vehicle speed limiter

Patent metadata

Field	Value
Publication number	US-11794738-B2
Application number	US-202017079960-A
Country	US
Kind code	B2
Filing date	Oct 26, 2020
Priority date	Oct 26, 2020
Publication date	Oct 24, 2023
Grant date	Oct 24, 2023

Abstract

According to one embodiment, a vehicle includes an electrified propulsion system having an electric machine powered by a traction battery over an electrical distribution system (EDS). A controller is programmed to, reduce a speed limit of the vehicle from a maximum speed limit to an EDS speed limit in response to a measured average current of the EDS being within a threshold percentage of an average current limit of the EDS, and, in response to a measured speed of the vehicle exceeding the EDS speed limit, command a torque to the electric machine that is less than a driver-demanded torque such that the vehicle is propelled at a speed below the EDS speed limit.

First claim

What is claimed is:

1. A vehicle comprising:
an electrified propulsion system including an electric machine powered by a traction battery over an electrical distribution system (EDS);
a current sensor configured to output a measured current associated with the EDS; and
a controller programmed to:
reduce a speed limit of the vehicle from a maximum speed limit to an EDS speed limit in response to an average of the measured current (measured average current) of the EDS being within a threshold percentage of an average current limit of the EDS, and
in response to a measured speed of the vehicle exceeding the EDS speed limit, command a torque to the electric machine that is less than a driver-demanded torque such that the vehicle is propelled at a speed below the EDS speed limit.

2. The vehicle of claim 1 , wherein a value of the EDS speed limit is based on a ratio between the measured average current and the average current limit.

3. The vehicle of claim 1 , wherein a value of the EDS speed limit increases as the measured average current decreases, and the value of the EDS speed limit decreases as the measured average current increases.

4. The vehicle of claim 1 , wherein a value of the EDS speed limit is based on a current capacity that is equal to a difference between the average current limit and the measured average current, divided by the average current limit.

5. The vehicle of claim 1 , wherein a value of the EDS speed limit decreases as the current capacity decreases.

6. The vehicle of claim 1 , wherein the threshold percentage is less than 35 percent.

7. The vehicle of claim 1 , wherein the torque commanded to the electric machine is based a speed of the vehicle and a maximum permissible acceleration of the vehicle.

8. The vehicle of claim 1 , wherein the driver-demanded torque is based on an accelerator pedal position.

9. A method of limiting vehicle speed based on current capacity of an electrical distribution system (EDS) associated with a traction battery, the method comprising:
reducing a speed limit of a vehicle from a maximum speed limit to an EDS speed limit in response to a measured average current of an EDS being within a threshold percentage of an average current limit of the EDS; and
in response to a measured speed of the vehicle exceeding the EDS speed limit, commanding a torque to an electric machine that is less than a driver-demanded torque such that the vehicle is propelled at a speed below the EDS speed limit.

10. The method of claim 9 further comprising:
setting a value of the EDS speed limit based on a ratio between the measured average current and the average current limit.

11. The method of claim 10 , wherein a value of the EDS speed limit increases as the measured average current decreases, and the value of the EDS speed limit decreases as the measured average current increases.

12. The method of claim 9 further comprising:
setting a value of the EDS speed limit based on a current capacity that is equal to a difference between the average current limit and the measured average current, divided by the average current limit.

13. The method of claim 12 , wherein a value of the EDS speed limit decreases as the current capacity decreases.

14. The method of claim 9 further comprising:
determining the driver-demanded torque based on an accelerator pedal position.

15. The method of claim 9 , wherein the threshold percentage is less than 35 percent.

Assignees

• Ford Global Tech Llc

Inventors

• March Zachary
• Bolger Bryan Michael
• Lepidi Gary
• Semenov Sergey Gennadievich

Classifications

• B60W30/146 Primary

  Speed limiting · CPC title

• B60K1/00

  Arrangement or mounting of electrical propulsion units (B60K7/00 takes precedence; arrangement or mounting of plural diverse prime-movers for mutual or common propulsion B60K6/00) · CPC title

• B60K1/04

  of the electric storage means for propulsion · CPC title

• B60K26/02

  of initiating means or elements · CPC title

• B60L15/20

  for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed · CPC title