Electric vehicle

• US 20030085063A1
• Filed: 11/04/2002
• Published: 05/08/2003
• Est. Priority Date: 11/06/2001
• Status: Active Grant

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Wakitani, Tsutomu, Kanke, Hiroo, Inui, Tsutomu
• Granted Patent: US 6,948,577 B2
• Time in Patent Office: Days
• US Class Current: 180/65.1
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: B60L 2220/42 with use of more than one motor
• CPC Class Codes: B60L 2220/46 Wheel motors, i.e. motor connected to only one wheel
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2270/145 Structure borne vibrations
• CPC Class Codes: B60L 50/60 using power supplied by batteries in combination with fuel cells B60L50/75
• CPC Class Codes: B60L 7/003 Dynamic electric braking by short circuiting the motor
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

An electric vehicle driven by at least one electric motor is provided. The vehicle includes a controller for controlling the electric motor and at least one braking device. The controller gradually reduces the rotational speed of the electric motor in accordance with a vehicle drive stop instruction, and operates the braking device when the rotational speed of the electric motor is equal to or lower than a predetermined rotational speed to stop the travel of the vehicle.

Claims

1. An electric vehicle comprising:

a directional speed member being able to instruct the forward travel, neutral state and reverse travel of said vehicle;

at least one electric motor which rotates in forward and reverse directions in accordance with the operation of said directional speed member, for propelling said vehicle;

a drive preparatory member which, when turned on, brings said at least one electric motor into a drivable state, and when turned off, brings said at least one electric motor into a drive stopped state;

at least one braking device for applying the brake to said at least one electric motor when said directional speed member is in neutral; and

a controller for gradually reducing a drive control signal to said at least one electric motor so as to reduce the rotational speed of said at least one electric motor, and thereafter operating said at least one braking device.

2. An electric vehicle as set forth in claim 1, wherein said controller repeatedly subjects a drive control signal of said at least one electric motor to a predetermined subtraction when, during vehicle travel, said drive preparatory member is turned off or said directional speed member is turned to a neutral state, thereby reducing the speed of said at least one electric motor until said at least one braking device becomes operable.

3. An electric vehicle as set forth in claim 1, wherein said vehicle comprises a pair of left and right electric motors and a pair of left and right braking devices and said controller reduces the speeds of said pair of left and right electric motors, respectively, when, during vehicle travel, said drive preparatory member is turned of for said directional speed member is turned to a neutral state, and simultaneously operates said pair of left and right braking devices when the rotational speed of at least one of said electric motors is reduced to a rotational speed threshold.

4. An electric vehicle as set forth in claim 1, wherein said vehicle comprises a pair of left and right electric motors and a pair of left and right braking devices and said controller reduces left and right drive control signals for controlling the drive of said pair of left and right electric motors when, during vehicle travel, said drive preparatory member is turned off or said directional speed member is turned to a neutral state, and simultaneously operates said pair of left and right braking devices when either of said drive control signals is reduced to a drive control signal threshold.

5. An electric vehicle as set forth in claim 1, wherein said vehicle comprises a pair of left and right electric motors and a pair of left and right braking devices and said controller reduces the speeds of said pair of left and right electric motors when, during vehicle travel, said drive preparatory member is turned off or said directional speed member in turned to a neutral state and a speed difference between the rotational speeds of said left and right electric motors is within a speed difference threshold, and simultaneously operates said pair of left and right braking devices when the rotational speed of at least one of said electric motors is reduced to a rotational speed threshold and said controller determines the ratio between the rotational speed of said left electric motor and the rotational speed of said right electric motor when the speed difference between the rotational speeds of said left and right electric motors exceeds said speed difference threshold, reduces the speeds of said left and right electric motors, respectively, by left and right control signal outputs according to said ratio, and simultaneously operates said left and right braking devices when at least one of the rotational speeds is reduced to said rotational speed threshold.