Hybrid powered construction equipment

• US 6,820,356 B2
• Filed: 03/13/2003
• Issued: 11/23/2004
• Est. Priority Date: 06/05/2002
• Status: Active Grant

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Ohtsukasa, Naritoshi, Naruse, Masami
• Primary Examiner(s): Pezzuto, Robert E.
• Assistant Examiner(s): Beach, Thomas A
• Application Number:
  US10/387,944
• Publication Number:
  US 20030226291A1
• Time in Patent Office: 621 Days
• Field of Search: 373/48, 373/47, 374/10, 374/14, 374/66, 701/50, 604/00, 604/20, 604/31
• US Class Current: 37/348
• CPC Class Codes: E02F 9/2075 of the hybrid type for vehicles in general B60W20/00
• CPC Class Codes: E02F 9/2221 Control of flow rate; Load sensing arrangements E02F9/2203 take precedence over E02F9/2221
• CPC Class Codes: E02F 9/2296 Systems with a variable displacement pump

Abstract

Hybrid powered construction equipment is capable of making effective use of the output energy of an engine; increasing operating speed while keeping noise level low, and assuring operation power more than the performance of the engine. To this end, the hybrid powered construction equipment has a hydraulic pump powered by the engine; hydraulic actuators activated by discharge oil from the hydraulic pump; a motor-generator working in conjunction with the engine; and a battery for storing electric power generated by the electric motor-generator, the construction equipment further comprising a power-up switch disposed in an operating lever or operation panel and a controller which inputs a signal released from the power-up switch, wherein the controller constantly controls the revolution speed of the engine in response to a signal from the power-up switch and controls the output torque of the electric motor-generator such that torque for assisting powering of the hydraulic pump is output.

Claims

1. A hybrid powered construction machine comprising:

an engine;

a hydraulic pump powered by the engine;

hydraulic actuators activated by discharge oil from the hydraulic pump;

an electric motor which works in conjunction with the engine;

a dynamo electric generator powered by the engine;

a battery for storing electric power generated by the dynamo electric generator;

a power-up switch disposed in one of an operating lever and an operation panel; and

a controller which constantly controls a revolution speed of the engine in response to a signal from the power-up switch, and controls an output torque of the electric motor such that torque for assisting powering of the hydraulic pump is outputted.

2. The hybrid powered construction machine according to claim 1, wherein during an ON state of the power-up switch, the controller controls the output torque of the electric motor in such a way that an absorbed torque of the hydraulic pump is compared to a rated output point torque of the engine, and if it is determined that the absorbed torque is lower than the rated output point torque, assisting torque is generated up to a proximity of the rated output point torque.

3. The hybrid powered construction machine according to claim 1, wherein during an ON state of the power-up switch, the controller controls the output torque of the electric motor in such a way that an absorbed torque of the hydraulic pump is compared to a rated output point torque of the engine, and if it is determined that the absorbed torque is equal to or in a vicinity the rated output point torque, assisting torque is outputted in an amount which exceeds the rated output point torque.

4. The hybrid powered construction machine according to claim 1, wherein the electric motor and the dynamo electric generator are provided as a single unit which is switchable between a motor operation mode and a generator operation mode.