CONTROL SYSTEM FOR CONSTRUCTION MACHINE

• US 20140039768A1
• Filed: 04/05/2012
• Published: 02/06/2014
• Est. Priority Date: 05/11/2011
• Status: Active Grant

• Current Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Ishikawa, Kouji, Satake, Hidetoshi, Nishikawa, Shinji, Ooki, Takatoshi, Sawada, Shingo
• Granted Patent: US 9,260,838 B2
• Time in Patent Office: Days
• US Class Current: 701/50
• CPC Class Codes: E02F 9/22 Hydraulic or pneumatic drives for dipper or bucket arm position control E02F3/43, for blade position control for graders E02F3/844; for turntables E02F9/121; for fork-lift trucks B66F9/22
• CPC Class Codes: E02F 9/2235 including an electronic controller
• CPC Class Codes: E02F 9/2246 Control of prime movers, e.g. depending on the hydraulic load of work tools
• CPC Class Codes: E02F 9/2296 Systems with a variable displacement pump
• CPC Class Codes: E02F 9/26 Indicating devices E02F5/145 takes precedence
• CPC Class Codes: F02D 29/04 peculiar to engines driving pumps
• CPC Class Codes: F15B 21/04 Special measures taken in connection with the properties of the fluid
• CPC Class Codes: F15B 21/082 with different modes
• CPC Class Codes: F15B 2211/20523 Internal combustion engine
• CPC Class Codes: F15B 2211/20546 variable capacity
• CPC Class Codes: F15B 2211/6651 Control of the prime mover, e.g. control of the output torque or rotational speed
• CPC Class Codes: F15B 2211/6652 Control of the pressure source, e.g. control of the swash plate angle
• CPC Class Codes: F15B 2211/6658 Control using different modes, e.g. four-quadrant-operation, working mode and transportation mode
• CPC Class Codes: F15B 2211/88 Control measures for saving energy

Abstract

A fuel-efficient hydraulic fluid has a lower viscosity than a standard hydraulic fluid, a pressure loss decreases, and thus, when control based on a standard model is exercised, the speeds of various actuators increase. However, the speeds need not be increased beyond the speeds of the standard model. Instead, it is preferred that fuel efficiency be improved. As a result, an engine revolution speed decreases by 50 rpm and a pump torque decreases by 5%. This reduces an engine output. Therefore, when a hydraulic fluid is changed from the standard hydraulic fluid to the fuel-efficient hydraulic fluid, the fuel efficiency can be improved while maintaining operability equivalent to that of the standard model. Hence, the fuel efficiency can be improved while maintaining the operability when an item affecting the fuel consumption is replaced. In addition, the settings can be changed with ease by a service technician.

Claims

1. A control system for a construction machine having a plurality of items including an engine (1), a hydraulic pump (2) driven by the engine, an actuator (4) driven by a hydraulic fluid discharged from the hydraulic pump, and a member driven by the actuator, at least one of the items being selectively changeable from one item state to another, the control system comprising:

item state selection means for selecting one of a plurality of item states; and

engine revolution speed/pump torque setting change means for changing the setting of an engine revolution speed and the setting of a pump torque in accordance with the item state selected by the item state selection means.

2. The control system according to claim 1, wherein the item that is selectively changeable from one item state to another is an item affecting the fuel consumption of the construction machine.

3. The control system according to claim 2, wherein the item affecting the fuel consumption of the construction machine is an item affecting the weight of a vehicle body.

4. The control system according to claim 2, wherein the item affecting the fuel consumption of the construction machine is an item affecting the fluid resistance of the hydraulic fluid.

5. The control system according to claim 4, wherein the item affecting the fluid resistance of the hydraulic fluid is the hydraulic fluid.

6. The control system according to claim 4, wherein the item affecting the fluid resistance of the hydraulic fluid is a hydraulic fluid conduit.

7. The control system according to claim 1, wherein the item state selection means includes a display screen of a monitor device.

8. The control system according to claim 1, wherein the engine revolution speed/pump torque setting change means defines the upper and lower limits for an increase and decrease in the engine revolution speed and in the pump torque and changes the setting of the engine revolution speed and the setting of the pump torque within the range between the upper and lower limits.