System and method for controlling engine revolutions for hybrid construction machine

• US 9,222,488 B2
• Filed: 10/15/2013
• Issued: 12/29/2015
• Est. Priority Date: 07/29/2009
• Status: Expired due to Fees

• Current Assignee: Volvo Construction Equipment Holding Sweden AB
• Original Assignee: Volvo Construction Equipment Holding Sweden AB
• Inventors: Jung, Ahn Kyun, Kim, Jae Hong, Lee, Chun Han, Jo, Jung Sun, Kang, Jong Min
• Primary Examiner(s): Restifo, Jeffrey J
• Application Number:
  US14/054,268
• Publication Number:
  US 20140086757A1
• Time in Patent Office: 805 Days
• Field of Search: 180/305, 180/307
• US Class Current: 1/1
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 2240/423 Torque
• 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 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/50 Control strategies for responding to system failures, e.g. for fault diagnosis, failsafe operation or limp mode
• CPC Class Codes: B60W 2510/0661 Torque change rate
• CPC Class Codes: B60W 2710/0661 Speed change rate
• 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 9/2246 Control of prime movers, e.g. depending on the hydraulic load of work tools
• CPC Class Codes: F15B 7/08 Input units; Master units
• CPC Class Codes: F16H 2059/6884 Sensing or calculating the pump torque
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility

Abstract

A system and method for controlling engine revolutions for a hybrid construction machine, including an engine, a hydraulic pump which is driven by the engine to drive a hydraulic actuator with discharged hydraulic fluid, a motor-generator which is driven by the engine to generate electricity and to drive the hydraulic pump as a motor supplementing the engine, an energy storage device which is charged with electric energy generated by the motor-generator and which supplies the electric energy for motor operation of the motor-generator, a torque detection unit for detecting an output torque of the hydraulic pump that is required to drive the hydraulic actuator, and a hybrid control unit for controlling the motor operation of the motor-generator to supplement the engine output if the change of the output torque of the hydraulic pump exceeds a predetermined level and it is determined that an engine revolution drop will occur.

Claims

1. A method for controlling engine revolutions in a control system for a hybrid construction machine, including an engine, a hydraulic pump which is driven by the engine to drive a hydraulic actuator with discharged hydraulic fluid, a motor-generator which is driven by the engine, to generate electricity and to drive the hydraulic pump as a motor supplementing the engine, and an energy storage device which is charged with electric energy generated by the motor-generator and which supplies the electric energy for motor operation of the motor-generator, the method comprising:

a torque detection step of detecting an output torque of the hydraulic pump that is required to drive the hydraulic actuator;

a drop determination step of determining the possibility of generating an engine revolution drop if the change of the output torque of the hydraulic pump detected in the torque detection step exceeds a predetermined level; and

a hybrid control step of controlling the motor operation of the motor-generator so as to supplement the engine output if it is determined that the engine revolution drop will occur in the drop determination step,

wherein the drop determination step determines the possibility of generating the engine revolution drop if the change of the output torque of the hydraulic pump exceeds the predetermined level due to an abrupt increase of load during operation.