# US 8,150,571 B2 · Braking force correcting method for electric golf car and electric golf car employing the correcting method

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- Number: US 8,150,571 B2
- Document ID: US8150571B2
- Status: Granted
- Kind: B2
- Application number: 12/059,276
- Filed: 2008-03-31
- Published: 2008-10-09
- Granted: 2012-04-03
- Earliest claimed: 2007-04-06
- Assignees: Yamaha Motor Electronics Co., Ltd.
- Inventors: Yukiyasu Takano
- Web page: https://patentgrep.com/patent/US8150571B2

## CPC

- B60T 1/10: by utilising wheel movement for accumulating energy, e.g. driving air compressors
- Y10S 903/947: Characterized by control of braking, e.g. blending of regeneration, friction braking
- B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

If a user applies a brake system while an electric vehicle that includes a battery is moving and it is confirmed that the user is not simultaneously applying the accelerator, a comparison is made between an actual deceleration and an expected deceleration corresponding to the user demand sensed by the braking system. If the actual deceleration is lower than the expected deceleration, an amount of regenerative electric current supplied to the battery is increased to better correlate the expected deceleration and the actual deceleration.

## Claims

### Claim 1

A braking force correcting method for an electric golf car comprising a battery, the method comprising:
checking an accelerator opening to determine if an accelerator opening is zero;
detecting a speed of the golf car and obtaining an actual deceleration;
detecting a demand level for brake application and obtaining an expected deceleration at the detected demand level;
if the accelerator opening is determined to be zero, a comparison is made between the actual deceleration and the expected deceleration, and if the actual deceleration is lower than the expected deceleration, an amount of regenerative electric current supplied to the battery is increased so that the actual deceleration increases toward the expected deceleration; and
if the accelerator opening is determined not to be zero, no comparison is made between the actual deceleration and the expected deceleration and the amount of regenerative electric current supplied to the battery is not increased.

### Claim 2 (depends on 1)

The method according to claim 1, wherein, if the actual deceleration is higher than the expected deceleration, the amount of regenerative electric current supplied to the battery is reduced so that the actual deceleration decreases toward the expected deceleration.

### Claim 3

An electric golf car comprising:
an accelerator opening detection device configured to detect operator demand for movement of the golf car by checking an accelerator opening to determine if the accelerator opening is zero;
a vehicle speed detection device configured to detect an operating speed of the golf car and to obtain an actual deceleration;
a brake pedal effort detection device configured to detect operator demand for stopping of the golf car by detecting a demand level for brake application and obtaining an expected deceleration at the detected demand level; and
a microcomputer configured to compute the actual deceleration and the expected deceleration and configured to compare the actual deceleration with the expected deceleration; wherein
the accelerator opening detection device and the brake pedal effort detection device are connected to the microcomputer;
the microcomputer is connected to a regenerative electric current amount adjusting device that is configured to change an amount of regenerative electric current supplied to the battery;
if the accelerator opening detection device determines that the accelerator opening is zero and if the microcomputer determines that the actual deceleration is lower than the expected deceleration, the microcomputer increases the amount of regenerative electric current supplied to the battery so that the actual deceleration increases toward the expected deceleration; and
if the accelerator opening detection device determines that the accelerator opening is not zero, the microcomputer does not compare the actual deceleration with the deceleration and does not change the amount of regenerative electric current supplied to the battery.

### Claim 4

An electric golf car, the golf car comprising:
an accelerator opening detection device configured to detect operator demand for movement of the golf car by checking an accelerator opening to determine if the accelerator opening is zero;
a vehicle speed detection device configured to detect an operating speed of the golf car and to obtain an actual deceleration;
a brake pedal effort detection device configured to detect operator demand for stopping of the golf car by detecting a demand level for brake application and obtaining an expected deceleration at the detected demand level; and
a microcomputer configured to compute the actual deceleration and the expected deceleration and configured to compare the actual deceleration with the expected deceleration; wherein
the accelerator opening detection device and the brake pedal effort detection device are connected to the microcomputer;
the microcomputer is connected to a regenerative electric current amount adjusting device that is configured to change an amount of regenerative electric current supplied to the battery;
if the accelerator opening detection device determines that the accelerator opening is zero and if the microcomputer determines that the actual deceleration is lower than the expected deceleration, the microcomputer increases the amount of regenerative electric current supplied to the battery so that the actual deceleration increases toward the expected deceleration;
if the accelerator opening detection device determines that the accelerator opening is zero and if the microcomputer determines that the actual deceleration is higher than the expected deceleration, the microcomputer decreases the amount of regenerative electric current supplied to the battery so that the actual deceleration decreases toward the expected deceleration; and
if the accelerator opening detection device determines that the accelerator opening is not zero, the microcomputer does not compare the actual deceleration with the expected deceleration and does not change the amount of regenerative electric current supplied to the battery.