Hybrid construction machine

• US 9,243,384 B2
• Filed: 06/20/2014
• Issued: 01/26/2016
• Est. Priority Date: 07/18/2013
• Status: Active Grant

• Current Assignee: Kobelco Construction Machinery Company Limited (Kobe Steel Limited)
• Original Assignee: Kobelco Construction Machinery Company Limited (Kobe Steel Limited)
• Inventors: Yamashita, Koji, Ueda, Koji, Hirozawa, Mitsunori
• Primary Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US14/310,279
• Publication Number:
  US 20150025726A1
• Time in Patent Office: 585 Days
• Field of Search: 701/22, 701/50, 180/65.285, 180/65.29, 903/903, 903/907
• US Class Current: 1/1
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 1/003 to auxiliary motors, e.g. for pumps, compressors
• CPC Class Codes: B60L 1/20 Energy regeneration from auxiliary equipment
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/25 by controlling the electric load
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: E02F 9/2075 of the hybrid type for vehicles in general B60W20/00
• CPC Class Codes: E02F 9/2091 Control of energy storage means for electrical energy, e.g. battery or capacitors energy recovery arrangements in hydraulic or pneumatic drives E02F9/2217
• CPC Class Codes: F15B 21/14 Energy-recuperation means
• CPC Class Codes: F15B 2211/20515 Electric motor
• CPC Class Codes: F15B 2211/20523 Internal combustion engine
• CPC Class Codes: F15B 2211/20569 capable of working as pump and motor
• CPC Class Codes: F15B 2211/88 Control measures for saving energy
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• 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: Y10S 903/907 : Electricity storage, e.g. battery, capacitor

Abstract

Provided is a hybrid construction machine preventing an electrical storage device from overcharge, including a hydraulic actuator, a hydraulic pump, a generator-motor which performs electric generator and motor actions, an engine, an electric actuator which generates regenerative electric power, an electrical storage device which performs a charge-and-discharge action with the generator-motor and the electric actuator, a charge-rate detector which detects a charge rate C1 of the electrical storage device, and a control section which controls an operation of the generator-motor and a charge-and-discharge action of the electrical storage device. The control section, when the charge rate C1 exceeds a set value Cs, performs overcharge-prevention control of making assist power by the electric motor action of the generator-motor be greater than that when C1≦Cs, the set value Cs predetermined as a charge rate at which receiving the regenerative electric power can overcharge the electrical storage device.

Claims

1. A hybrid construction machine comprising:

a hydraulic actuator;

a hydraulic pump which provides hydraulic power to the hydraulic actuator;

a generator-motor which performs an electric generator action for generating electric power and an electric motor action for providing assist power to assist the engine;

an engine which provides driving power to the hydraulic pump and the generator-motor, the engine connected to the generator-motor to receive the assist power from the generator-motor;

an electric actuator which generates regenerative electric power;

an electrical storage device which performs a charge-and-discharge action of supplying and receiving electric power to and from the generator-motor and the electric actuator;

a charge rate detector which detects a charge rate C1 of the electrical storage device; and

a control section which controls an operation of the generator-motor and the charge-and-discharge action of the electrical storage device, wherein

when the charge rate C1 detected by the charge rate detector is greater than a predetermined charge rate Cs at which the electrical storage device is likely to be overcharged by receiving the regenerative electric power generated by the electric actuator, the control section performs overcharge-prevention control of making the assist power greater than that when C1≦

Cs.

2. The hybrid construction machine according to claim 1, wherein the overcharge-prevention control includes setting a maximum assist power D, which is a maximum power by which the generator-motor can assist.

3. The hybrid construction machine according to claim 2, wherein the maximum assist power D is set as D=(A+B) when C1>

Cs, where A represents a pump-requirement power obtained from a pressure and a flow rate of the hydraulic pump, and B represents a total power for the engine which is a sum of a power required to drive a main body of the engine and a power required to co-rotationally drive accessory parts of the engine, the accessory parts excluding the hydraulic pump.

4. The hybrid construction machine according to claim 2, wherein the maximum assist power D is set as D=A when C1≦

Cs, where A represents a pump-requirement power obtained from a pressure and a flow rate of the hydraulic pump.

5. The hybrid construction machine according to claim 4, wherein the maximum assist power D is set as D=(A+B) when C1>

Cs, where B represents a total power of the engine which is a sum of a power required to drive a main body of the engine and a power required to co-rotationally drive accessory parts of the engine, the accessory parts excluding the hydraulic pump.

6. The hybrid construction machine according to claim 2, wherein the control section obtains a required assist power G which must be consumed by the generator-motor in accordance with G=(E−

F), sets the obtained required assist power as the assist power of the generator-motor when D≧

G, and sets the maximum assist power as the assist power of the generator-motor when D<

G, where E represents a regenerative power generated by the electric actuator, F represents an electrically chargeable power which is an available capacity of the electrical storage device and is obtained from a charge rate of the electrical storage device.

7. The hybrid construction machine according to claim 6, further comprising a temperature detector that detects a temperature of the electrical storage device, wherein the electrically chargeable power F is obtained from a detected charge rate C1 and a detected electrical-storage device temperature.