ENGINE CONTROL DEVICE OF CONSTRUCTION MACHINE

• US 20100235060A1
• Filed: 09/29/2008
• Published: 09/16/2010
• Est. Priority Date: 11/13/2007
• Status: Active Grant

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Yamada, Takeo
• Granted Patent: US 9,121,158 B2
• Time in Patent Office: Days
• US Class Current: 701/50
• CPC Class Codes: E02F 9/2246 Control of prime movers, e.g. depending on the hydraulic load of work tools
• CPC Class Codes: E02F 9/2292 Systems with two or more pumps
• CPC Class Codes: E02F 9/2296 Systems with a variable displacement pump
• CPC Class Codes: F02D 29/04 peculiar to engines driving pumps
• CPC Class Codes: F02D 41/021 Introducing corrections for particular conditions exterior to the engine conjoint control of vehicle sub-units for propelling the vehicle B60W30/18
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine

Abstract

An engine control device is adapted to be used for a construction machine equipped with an engine, a hydraulic pump to be driven by the engine, a revolving motor for revolving an upper structure by means of hydraulic oil to be supplied from the hydraulic pump, and a revolving operation lever for executing an operation of revolving the upper structure. The engine control device includes an operation amount detection unit configured to detect an operation amount of the revolving operation lever, and a control unit configured to increase a maximum engine speed when a result of detection by the operation amount detection unit is greater than a predetermined threshold.

Claims

1. An engine control device of a construction machine equipped with an engine, a hydraulic pump to be driven by the engine, a revolving motor for revolving an upper structure by means of hydraulic oil to be supplied from the hydraulic pump, and a revolving operation lever for executing an operation of revolving the upper structure, the engine control device comprising:

an operation amount detection unit configured to detect an operation amount of the revolving operation lever; and

a control unit configured to increase a maximum revolution of the engine speed when a result of detection by the operation amount detection unit is greater than a predetermined threshold.

3. The engine control device of a construction machine according to claim 1, wherein

the control unit is configured to control the engine in one of:

a power mode in which an output torque of the engine and an absorption torque of the hydraulic pump are matched in a condition that both of the engine speed and the engine output torque are relatively high; and

an economy mode in which an engine output torque characteristic is set to be lower than that of the power mode, and

the control unit is configured to execute a control of increasing the engine speed during the power mode.

4. The engine control device of a construction machine according to claim 1, wherein

the control unit is configured to control the engine according to one of a plurality of engine torque curves.

5. The engine control device of a construction machine according to claim 4, wherein

the control unit is configured to select a prescribed engine torque curve from said plurality of engine torque curves in accordance with the operation amount of the revolving operation lever, and

the control unit is configured to set an upper limit of the torque on the selected engine torque curve depending on an operation condition of an actuator of the construction machine other than the upper structure.

6. The engine control device of a construction machine according to claim 1, wherein

the control unit is configured to:

activate the engine speed control when the operation amount of the revolving operation lever is greater than a first threshold; and

deactivate the engine speed control when the operation amount of the revolving operation lever is less than a second threshold, the second threshold being less than the first threshold.

7. The engine control device of a construction machine according to claim 1, wherein

the hydraulic pump is a revolving standalone pump that supplies hydraulic oil to drive the upper structure.

2. An engine control device of a construction machine equipped with an engine, a hydraulic pump to be driven by the engine, a revolving motor for revolving an upper structure by means of hydraulic oil to be supplied from the hydraulic pump, and a revolving operation lever for executing an operation of revolving the upper structure, the engine control device comprising:

an operation amount detection unit configured to detect an operation amount of the revolving operation lever; and

a control unit configured to control the engine according to one of two engine torque curves with different maximum engine speeds, and to switch to the engine torque curve with a higher maximum engine speed when the detection result by the operation amount detection unit is greater than a predetermined threshold under a condition that the engine torque curve with the lower maximum engine speed is being selected.