Hybrid construction equipment

• US 6,708,787 B2
• Filed: 02/25/2002
• Issued: 03/23/2004
• Est. Priority Date: 03/12/2001
• Status: Expired due to Fees

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Kimoto, Kenzo, Tamaru, Masatake, Naruse, Masami
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): Campbell, Kelly E
• Application Number:
  US10/080,678
• Publication Number:
  US 20020125052A1
• Time in Patent Office: 757 Days
• Field of Search: 172/2, 172/4.5, 172/7, 374/11, 373/48, 180/53.8
• US Class Current: 180/53.8
• CPC Class Codes: B60K 6/12 by means of a chargeable fluidic accumulator
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• 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 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: E02F 9/2075 of the hybrid type for vehicles in general B60W20/00
• CPC Class Codes: E02F 9/2217 with energy recovery arrangements, e.g. using accumulators, flywheels
• CPC Class Codes: F04B 17/03 driven by electric motors
• CPC Class Codes: F04B 17/05 driven by internal-combustion engines
• CPC Class Codes: F04B 2201/1202 Torque on the axis
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/903 having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/918 Continuously variable

Abstract

Hybrid construction equipment leveling an engine load and effectively performing regeneration of energy is provided. For this purpose, the construction equipment includes a hydraulic pump (2) and a first electric motor (7) driven by an engine (1), a battery (9) for charging electric power generated by the first electric motor, a second electric motor (10) driven by electric power of the battery and functioning as a generator at a time of braking revolution, a swash plate angel sensor 33 and a pressure sensor 34 for the hydraulic pump, and a controller (5) for controlling the first electric motor as a generator by surplus torque when absorption torque is smaller than predetermined output torque of the engine and controlling the first electric motor as a motor to generate an amount of shortage of torque when the absorption torque is larger than the predetermined torque.

Claims

1. Hybrid construction equipment comprising, on an upper revolving superstructure rotatably placed on a lower traveling unit,

an engine,

a hydraulic pump driven by said engine,

a hydraulic actuator driven by discharge oil from said hydraulic pump,

a first electric motor driven by said engine,

a battery for charging electric power generated by said first electric motor, and

a second electric motor driven by electric power of said battery,

wherein said second electric motor is the electric motor for revolving said upper revolving superstructure, which functions as a generator at a time of braking revolution of said upper revolving superstructure and charges generated electric power into said battery,

said hybrid construction equipment further comprising:

absorption torque detecting means for detecting absorption torque of said hydraulic pump;

a controller for comparing predetermined output torque of said engine fixed according to an engine characteristic and absorption torque of said hydraulic pump detected by said absorption torque detecting means, controlling said first electric motor to function as a generator by surplus torque when the absorption torque of said hydraulic pump is smaller than the predetermined output torque of said engine, and controlling said first electric motor to function as a motor so that it generates an amount of shortage of torque when the absorption torque of said hydraulic pump is larger than the predetermined torque of said engine; and

a hydraulic motor rotated by return oil from a bottom side of said hydraulic actuator.

2. The hybrid construction equipment according to claim 1,

wherein said hydraulic actuator is a boom cylinder,

said hybrid construction equipment further comprising:

a generator connected to said hydraulic motor and charging generated electric power into said battery.