System and method of controlling vehicle of construction equipment

Patent metadata

Field	Value
Publication number	US-9382694-B2
Application number	US-201414577489-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Dec 20, 2013
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

The present disclosure relates to a system and method of controlling a vehicle of construction equipment, which calculate a target engine torque from compensation torque information using torque information generated in a hydraulic pump and an engine speed error and transmit the calculated target engine torque, thereby more stably performing engine control while responding to a rapid load variation of the hydraulic pump.

First claim

What is claimed is:

1. A system for controlling a vehicle of construction equipment, comprising:
an engine;
a hydraulic pump operated by power supplied from the engine;
one or more actuators driven by a hydraulic pressure discharged from the hydraulic pump;
a hydraulic pump control device including circuitry configured to:
calculate a compensation torque according to a hydraulic pump torque and an engine speed error between an actual engine RPM and a target engine RPM;
compensate for the hydraulic pump torque with the calculated compensation torque; and
output a compensated hydraulic pump torque as a target engine torque; and
an engine control circuit configured to control a torque of the engine based on the outputted target engine torque.

2. The system of claim 1 , wherein the hydraulic pump control device includes:
a hydraulic pump torque calculating circuit configured to calculate the hydraulic pump torque by using a discharge capacity and a discharge pressure of the hydraulic pump;
a speed error calculating circuit configured to calculate the engine speed error between the actual engine RPM and the target engine RPM;
a target torque information transmitting circuit configured to transmit the output target engine torque to the engine control circuit.

3. The system of claim 2 , wherein the hydraulic pump torque calculating circuit calculates the discharge capacity of the hydraulic pump by using a pressure selected from a pressure for power shift control and a negacon pressure, and the discharge pressure of the hydraulic pump.

4. The system of claim 2 , wherein when the hydraulic pump is an electronic pump controlled by a current value, the hydraulic pump torque calculating circuit calculates the discharge capacity of the hydraulic pump by using a value of a swash plate angle sensor, or a current command value for controlling a swash plate angle and a value of a discharge pressure sensor.

5. The system of claim 2 , wherein the hydraulic pump torque calculating circuit calculates the discharge capacity of the hydraulic pump by using a control pressure of a regulator which controls a swash plate angle or a value of a swash plate angle sensor.

6. The system of claim 2 , wherein the hydraulic pump torque calculating circuit generates a delay in the hydraulic pump torque increased according to an increase in the discharge pressure of the hydraulic pump to compensate for a time delay of a swash plate angle of the hydraulic pump.

7. The system of claim 2 , wherein the hydraulic pump torque calculating circuit calculates the hydraulic pump torque by using a temperature of working fluid in addition to the discharge pressure of the hydraulic pump, a pressure for power shift control, and a regulator control value.

8. The system of claim 2 , wherein a compensation torque calculating circuit calculates the compensation torque by using a table according to the calculated engine speed error and a load quantity, or a PID controller.

9. The system of claim 2 , wherein an input value of a regulator, which controls a swash plate angle of the hydraulic pump is at least one of a negacon pressure, a posicon pressure, and a posicon input signal.

10. The system of claim 2 , wherein the hydraulic pump control device further includes:
an engine torque information receiving circuit configured to receive engine torque limit information and current engine torque information;
a hydraulic pump output limit calculating circuit configured to calculate a hydraulic pump output limit, which is to be commanded to the hydraulic pump, by using the engine torque limit information received through the engine torque information receiving circuit;
a hydraulic pump flow rate control determining circuit configured to determine whether a current hydraulic pump output calculated by using a pump discharge pressure and a pump model is greater than a hydraulic pump output limit calculated by the hydraulic pump output limit calculating circuit, determine whether a difference value between the current engine torque information and the engine torque limit information is equal to or smaller than a predetermined reference value, and determine whether a flow rate limit control function is activated; and
a hydraulic pump flow rate limit control circuit configured to control an output of the hydraulic pump in proportion to the difference value between the current hydraulic pump output and the hydraulic pump output limit when the flow rate limit control function is activated according to a result of the determination of the hydraulic pump flow rate control determining circuit.

11. The system of claim 10 , further comprising:
a rapid load determining circuit configured to determine whether a rapid load is generated by using an increase rate of the pump discharge pressure,
wherein when the rapid load is generated in the hydraulic pump according to a result of the determination of the rapid load determining circuit, the engine torque information receiving circuit receives the engine torque limit information and the current engine torque information.

12. A method of controlling a vehicle of construction equipment, comprising:
calculating a hydraulic pump torque by using a discharge capacity and a discharge pressure of a hydraulic pump;
calculating an engine speed error between an actual engine RPM and a target engine RPM;
calculating a compensation torque by using the calculated hydraulic pump torque and the calculated engine speed error;
compensating for the calculated hydraulic pump torque with the calculated compensation torque; and
outputting the compensated torque as a target engine torque; and
controlling, by an engine control circuit, a torque of an engine based on the outputted engine target torque.

13. The method of claim 12 , wherein the calculating of the hydraulic pump torque includes calculating the discharge capacity of the hydraulic pump by using a pressure selected from a pressure for power shift control and a negacon pressure, and the discharge pressure of the hydraulic pump.

14. The method of claim 12 , wherein the calculating of the hydraulic pump torque includes, when the hydraulic pump is an electronic pump controlled by a current value, calculating the discharge capacity of the hydraulic pump by using a value of a swash plate angle sensor, or a current command value for controlling a swash plate angle and a value of a discharge pressure sensor.

15. The method of claim 12 , wherein the calculating of the hydraulic pump torque includes generating a delay in the hydraulic pump torque increased according to an increase in the discharge pressure of the hydraulic pump to compensate for a time delay of a swash plate angle of the hydraulic pump.

16. The method of claim 12 , wherein the calculating of the hydraulic pump torque includes calculating the hydraulic pump torque by using a temperature of working fluid in addition to the discharge pressure of the hydraulic pump, a pressure for power shift control, and a regulator control value.

17. The method of claim 12 , wherein the calculating of the compensation torque includes calculating the compensation torque by using a table according to the calculated engine speed error and a load quantity, or a PID controller.

18. The method of claim 12 , wherein an input value of a regulator, which controls a swash plate angle of the hydraulic pump is at least one of a negacon pressure, a posicon pressure, and a posicon input signal.

19. The method of claim 12 , further comprising:
receiving engine torque limit information

Assignees

• Doosan Infracore Co Ltd

Inventors

• Kim Dong Mok
• Cho Lee Hyoung

Classifications

• B60W10/30

  including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps · CPC title

• E02F9/2235

  including an electronic controller · CPC title

• B60W2710/0666

  Engine torque · CPC title

• E02F9/2246 Primary

  Control of prime movers, e.g. depending on the hydraulic load of work tools · CPC title

• F02D29/04

  peculiar to engines driving pumps · CPC title