Eco-friendly vehicle and hill descent control method for the same

Patent metadata

Field	Value
Publication number	US-2020171956-A1
Application number	US-201916595994-A
Country	US
Kind code	A1
Filing date	Oct 8, 2019
Priority date	Dec 3, 2018
Publication date	Jun 4, 2020
Grant date	—

Abstract

An eco-friendly vehicle and a hill descent control method therefor are provided to enable stable driving on a downhill road. The method includes detecting a downhill road inclination based on a request for hill descent control and determining an average inclination and an inclination variation width based on the recognized downhill road inclination. First braking force of a main braking source from a motor and a hydraulic pressure brake system based on the average inclination and the inclination variation width, and second braking force of an auxiliary braking source from the motor and the hydraulic pressure brake system for each driving wheel based on a target speed set with respect to the hill descent control and a speed of each driving wheel are determined. The first and second braking force are output by a corresponding braking source from the motor and the hydraulic pressure brake system.

First claim

What is claimed is:

1 . A hill descent control method of an eco-friendly vehicle, comprising:
detecting, by a controller, a downhill road inclination in response to a request for hill descent control; determining, by the controller, an average inclination and an inclination variation width based on the recognized downhill road inclination; determining, by the controller, first braking force of a main braking source from a motor or a hydraulic pressure brake system based on the average inclination and the inclination variation width; determining, by the controller, second braking force of an auxiliary braking source from the motor or the hydraulic pressure brake system for each driving wheel based on a target speed set with respect to the hill descent control and a speed of each driving wheel; and outputting, by the controller, the first braking force and the second braking force by a corresponding braking source from the motor and the hydraulic pressure brake system.

2 . The method of claim 1 , wherein, when the motor is connected to each driving wheel through a differential gear, the main braking source is the motor and the auxiliary braking source is the hydraulic pressure brake system.

3 . The method of claim 1 , wherein, when two or more motors are connected to each driving wheel, the main braking source is the hydraulic pressure brake system and the auxiliary braking source is the two or more motors connected to each of the driving wheel.

4 . The method of claim 1 , wherein the motor is configured to output any one of the first braking force and the second braking force through regenerative brake.

5 . The method of claim 1 , wherein detecting the downhill road inclination includes:
obtaining, by the controller, wheel acceleration based on an average speed of four wheels included in the eco-friendly vehicle; and obtaining, by the controller, the downhill road inclination based on a value obtained by subtracting the wheel acceleration from an acceleration sensor value.

6 . The method of claim 1 , wherein determining the average inclination and the inclination variation width includes:
obtaining, by the controller, the average inclination using an average of the downhill road inclination present in a moving window with a predetermined time length; and obtaining, by the controller, the inclination variation width based on downhill road inclination distribution with predetermined reliability based on the average inclination in the moving window.

7 . The method of claim 1 , wherein the first braking force corresponds to a value obtained by subtracting a control margin corresponding to the inclination variation width from braking force corresponding to the average inclination.

8 . The method of claim 1 , wherein determining the second braking force includes:
obtaining, by the controller, speed error for each driving wheel by subtracting a linear speed for a vehicle wheel, obtained based on the speed for each driving wheel, from the target speed; and determining, by the controller, the second braking force for each driving wheel to reduce the speed error.

9 . The method of claim 1 , wherein: the first braking force is determined in the form of feedforward control; and the second braking force is determined in the form of feedback control.

10 . A non-transitory computer readable recording medium having recorded thereon a program for executing the hill descent control method of the eco-friendly vehicle of claim 1 .

11 . An eco-friendly vehicle, comprising:
a first controller configured to:
detect a downhill road inclination in response to a request for hill descent control;
determine an average inclination and an inclination variation width based on the recognized downhill road inclination;
determine first braking force of a main braking source from a motor or a hydraulic pressure brake system based on the average inclination and the inclination variation width; and
determine second braking force of an auxiliary braking source from the motor or the hydraulic pressure brake system for each driving wheel based on a target speed set with respect to the hill descent control and a speed of each driving wheel;
a second controller configured to operate the motor to output any corresponding one of the first braking force and the second braking force; and a third controller configured to operate the hydraulic pressure brake system to output another corresponding one of the first braking force and the second braking force.

12 . The eco-friendly vehicle of claim 11 , wherein, when the motor is connected to each driving wheel through a differential gear, the main braking source is the motor and the auxiliary braking source is the hydraulic pressure brake system.

13 . The eco-friendly vehicle of claim 11 , wherein, when two or more motors are connected to each driving wheel, the main braking source is the hydraulic pressure brake system and the auxiliary braking source is the two or more motors connected to each of the driving wheel.

14 . The eco-friendly vehicle of claim 11 , wherein the motor outputs any one of the first braking force and the second braking force through regenerative brake.

15 . The eco-friendly vehicle of claim 11 , wherein the first controller is configured to obtain wheel acceleration based on an average speed of four wheels included in the eco-friendly vehicle and obtain the downhill road inclination based on a value obtained by subtracting the wheel acceleration from an acceleration sensor value.

16 . The eco-friendly vehicle of claim 11 , wherein the first controller is configured to obtain the average inclination using an average of the downhill road inclination present in a moving window with a predetermined time length and obtain the inclination variation width based on downhill road inclination distribution with predetermined reliability based on the average inclination in the moving window.

17 . The eco-friendly vehicle of claim 11 , wherein the first braking force corresponds to a value obtained by subtracting a control margin corresponding to the inclination variation width from braking force corresponding to the average inclination.

18 . The eco-friendly vehicle of claim 11 , wherein the first controller is configured to obtain speed error for each driving wheel by subtracting a linear speed for a vehicle wheel, obtained based on the speed for each driving wheel, from the target speed and determine the second braking force for each driving wheel to reduce the speed error.

19 . The eco-friendly vehicle of claim 11 , wherein the first braking force is determined in the form of feedforward control and the second braking force is determined in the form of feedback control.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Park Joon Young

Classifications

• B60L7/26 Primary

  Controlling the braking effect · CPC title

• B60T8/171

  Detecting parameters used in the regulation; Measuring values used in the regulation · CPC title

• B60T13/586

  the retarders being of the electric type · CPC title

• B60T8/245 Primary

  Longitudinal vehicle inclination · CPC title

• B60W20/00

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