Construction machine

• US 9,617,715 B2
• Filed: 02/04/2016
• Issued: 04/11/2017
• Est. Priority Date: 08/31/2011
• Status: Active Grant

• Current Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Ishida, Seiji, Satake, Hidetoshi, Kajita, Yusuke, Yamaoka, Shiro
• Primary Examiner(s): SOOFI, YAZAN A
• Application Number:
  US15/015,453
• Publication Number:
  US 20160153176A1
• Time in Patent Office: 432 Days
• Field of Search: 701 22
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60L 1/003 to auxiliary motors, e.g. for pumps, compressors
• 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 2220/14 Synchronous machines
• CPC Class Codes: B60L 2220/42 with use of more than one motor
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 2270/12 of exhaust
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 20/00 : Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/16 : for reducing engine exhaust emissions
• CPC Class Codes: B60W 2050/0055 : High-pass filters
• CPC Class Codes: B60W 2300/17 : Construction vehicles, e.g. graders, excavators
• CPC Class Codes: B60W 2510/0657 : Engine torque
• CPC Class Codes: B60W 2510/0661 : Torque change rate
• CPC Class Codes: B60W 2510/081 : Speed
• CPC Class Codes: B60W 2510/083 : Torque
• CPC Class Codes: B60W 2510/30 : Auxiliary equipments
• CPC Class Codes: B60W 2710/081 : Speed
• CPC Class Codes: E02F 3/32 : working downwardly and towards the machine, e.g. with backhoes
• CPC Class Codes: E02F 9/207 : of the type electric propulsion units, e.g. electric motors or generators
• CPC Class Codes: E02F 9/2075 : of the hybrid type for vehicles in general B60W20/00
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• 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 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y10S 903/902 : Prime movers comprising electrical and internal combustion motors

Abstract

A construction machine including an internal combustion engine controlled based on a torque command, an electric motor mechanically connected to the internal combustion engine, and an electric energy storage device that supplies electric power to the electric motor, the construction machine performing work by driving a hydraulic pressure generator using the internal combustion engine and the electric motor, the construction machine including: a speed control device that controls a speed of the electric motor based on a speed command; and a torque limiter that limits the torque command relative to a torque target, wherein the torque command is limited by the torque limiter in such a manner that a rate of change with time of the torque command is limited to be equal to or less than a predetermined value.

Claims

1. A construction machine comprising:

an internal combustion engine controlled based on a torque command;

an engine controller that controls the internal combustion engine such that an output torque of the internal combustion engine becomes equal to the torque command;

an electric motor mechanically connected to the internal combustion engine;

an electric energy storage device that supplies electric power to the electric motor, the construction machine performing work by driving a hydraulic pressure generator using the internal combustion engine and the electric motor;

a speed control device that controls a speed of the electric motor based on a speed command; and

a torque limiter that outputs a torque command relative to a torque target of the internal combustion engine to the controller, wherein

the torque limiter limits the torque command relative to the torque target of the internal combustion engine such that a rate of change with time of the torque target of the internal combustion engine becomes equal to or less than a predetermined value.

2. The construction machine according to claim 1, wherein

the internal combustion engine is controlled by a first torque command obtained based on the speed command and the speed, and

the speed control device

calculates a second torque command obtained based on the speed command and the speed of the electric motor,

further includes a high-pass filter that removes a low-frequency component including a DC component of the second torque command, and

controls the electric motor based on an output of the high-pass filter.

3. The construction machine according to claim 1, wherein

the electric motor is speed-controlled by the speed command, and

torque of the internal combustion engine is greater than torque of the electric motor when a rate of change with time in torque of the hydraulic pressure generator is low, and the torque of the electric motor is greater than the torque of the internal combustion engine when the rate of change with time in the torque of the hydraulic pressure generator is high.

4. The construction machine according to claim 1, wherein

the electric motor is speed-controlled by the speed command, and

a change of a rate of change with time in the torque of the internal combustion engine is higher than a change of a rate of change with time in the torque of the hydraulic pressure generator when the rate of change with time in the torque of the hydraulic pressure generator is low, and the change of the rate of change with time in the torque of the internal combustion engine is lower than the change of the rate of change with time in the torque of the hydraulic pressure generator when the rate of change with time in the torque of the hydraulic pressure generator is high.

5. The construction machine according to claim 1, wherein

the torque target is obtained based on a charge amount of the electric energy storage device.

6. A construction machine comprising:

an internal combustion engine;

an electric motor mechanically connected to the internal combustion engine; and

an electric energy storage device that supplies electric power to the electric motor;

the construction machine performing work by driving a hydraulic pressure generator using the internal combustion engine and the electric motor;

wherein the electric motor is speed-controlled by a speed command; and

torque of the internal combustion engine is greater than torque of the electric motor when a rate of change with time in torque of the hydraulic pressure generator is low; and

the torque of the electric motor is greater than the torque of the internal combustion engine when the rate of change with time in the torque of the hydraulic pressure generator is high.

7. A construction machine comprising:

an internal combustion engine;

an electric motor mechanically connected to the internal combustion engine; and

an electric energy storage device that supplies electric power to the electric motor;

the construction machine performing work by driving a hydraulic pressure generator using the internal combustion engine and the electric motor;

wherein the electric motor is speed-controlled by the speed command; and

a change of a rate of change with time in torque of the internal combustion engine is higher than a change of a rate of change with time in torque of the hydraulic pressure generator when the rate of change with time in the torque of the hydraulic pressure generator is low; and

the change of the rate of change with time in the torque of the internal combustion engine is lower than the change of the rate of change with time in the torque of the hydraulic pressure generator when the rate of change with time in the torque of the hydraulic pressure generator is high.