HYBRID-TYPE CONSTRUCTION MACHINE AND CONTROL METHOD FOR HYBRID-TYPE CONSTRUCTION MACHINE

• US 20120089288A1
• Filed: 06/15/2010
• Published: 04/12/2012
• Est. Priority Date: 06/19/2009
• Status: Active Grant

• Current Assignee: Sumitomo Heavy Industries Limited
• Original Assignee: Sumitomo Heavy Industries Limited
• Inventors: Kawashima, Koji
• Granted Patent: US 8,739,906 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 6/485 Motor-assist type
• 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 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 2510/1075 fluid pressure, e.g. oil pressure
• CPC Class Codes: E02F 9/123 Drives or control devices specially adapted therefor E02F9/125 and E02F9/128 take precedence
• 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: F02D 29/04 peculiar to engines driving pumps
• CPC Class Codes: F02D 29/06 peculiar to engines driving electric generators
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A hybrid-type construction machine includes a controller configured to control a revolution speed of an engine; a hydraulic pump configured to be driven by the engine; a motor generator configured to assist the engine; and a hydraulic circuit configured to supply an operating oil discharged from the hydraulic pump to a hydraulic load, wherein when the controller determines that the hydraulic circuit is in an excessive output state, the controller controls the revolution speed of the engine so as to be lower than an ordinary revolution speed of the engine while controlling the motor generator to generate electricity.

Claims

1. A hybrid-type construction machine comprising:

a controller configured to control a revolution speed of an engine;

a hydraulic pump configured to be driven by the engine;

a motor generator configured to assist the engine; and

a hydraulic circuit configured to supply an operating oil discharged from the hydraulic pump to a hydraulic load,

wherein when the controller determines that the hydraulic circuit is in an excessive output state, the controller controls the revolution speed of the engine so as to be lower than an ordinary revolution speed of the engine while controlling the motor generator to generate electricity.

2. The hybrid-type construction machine according to claim 1, further comprising:

a first pressure sensor configured to detect a pressure of the operating oil discharged from the hydraulic pump;

a control valve provided in the hydraulic circuit and configured to control a flow of the operating oil into the hydraulic load; and

a negative control metering valve provided between the control valve and the tank; and

a second pressure sensor provided between the control valve and the negative control metering valve and configured to detect negative control pressure,

wherein the controller compares a first discharge quantity of the hydraulic pump acquired from a detection value of the first pressure sensor with a second discharge quantity of the hydraulic pump acquired from a detection value of the second pressure sensor, and

the controller controls the revolution speed of the engine so as to be lower than the ordinary revolution speed of the engine while controlling the motor generator to generate the electricity depending on a result of the comparison.

3. The hybrid-type construction machine according to claim 1, further comprising:

a relief valve configured to return the operating oil discharged from the hydraulic pump to a tank when a pressure inside the hydraulic circuit exceeds a predetermined pressure,

wherein, while the operating oil is returned to the tank via the relief valve, the controller controls the revolution speed of the engine so as to be lower than the ordinary revolution speed of the engine while controlling the motor generator to generate the electricity.

4. The hybrid-type construction machine according to claim 3, further comprising:

a detecting unit configured to detect a value indicative of the pressure inside the hydraulic circuit,

wherein the controller increases or decreases the revolution speed of the engine based on the value detected by the detecting unit.

5. The hybrid-type construction machine according to claim 4,

wherein the detecting unit includes a fluid meter configured to detect a flow rate of the operating oil returned from the relief valve to the tank, and

the controller changes the revolution speed of the engine based on the flow rate detected by the fluid meter.

6. The hybrid-type construction machine according to claim 1,

wherein the controller controls the motor generator so as to run as a motor when the revolution speed of the engine is increased.

7. The hybrid-type construction machine according to claim 1,

wherein the controller controls the motor generator with a torque control when the revolution speed of the engine is maintained to have a predetermined value.

8. The hybrid-type construction machine according to claim 1,

wherein the controller controls the motor generator with a revolution speed control when the revolution speed of the motor generator is increased or decreased.

9. The hybrid-type construction machine according to claim 1,

wherein the controller determines that the hydraulic circuit is in the excessive output state relative to an operation condition of the hydraulic load.

10. A control method of a hybrid-type construction machine including

a hydraulic pump configured to be driven by the engine;

a motor generator configured to assist the engine; and

a hydraulic circuit configured to supply an operating oil discharged from the hydraulic pump to a hydraulic load, the control method comprising;

determining whether the hydraulic circuit is in an excessive output state; and

controlling a revolution speed of the engine so as to be lower than an ordinary revolution speed of the engine by controlling the motor generator to generate electricity.

11. The control method of the hybrid-type construction machine according to claim 10,

wherein the controlling is to run the motor generator as a motor when the revolution speed of the engine is increased.

12. The control method of the hybrid-type construction machine according to claim 10,

wherein the controlling is to control the motor generator with a torque control when the revolution speed of the engine is maintained to have a predetermined value.

13. The control method of the hybrid-type construction machine according to claim 10,

wherein the controlling is to control the motor generator with a revolution speed control when the revolution speed of the motor generator is increased or decreased.

14. The control method of the hybrid-type construction machine according to claim 10,

wherein the controlling is to determine that the hydraulic circuit is in the excessive output state relative to an operation condition of the hydraulic load.