Multi-step regeneration device of DPF and regeneration method therefor

1. A multi-step regeneration apparatus of a diesel particulate filter (DPF), which generates a load to an engine to remove soot, the apparatus comprising:

an external air temperature sensor configured to measure a temperature of external air;

a controller configured to compare an external air temperature value measured by the external air temperature sensor with a predetermined value and output a signal; and

a control valve unit, which is a hydraulic load device, including a first control valve and a second control valve receiving the signal from the controller, and a first spool operated by the first control valve and a second spool operated by the second control valve;

wherein the control valve unit further includes a first relief valve having a set pressure (P 1 ) and a second relief valve having a set pressure (P 2 ) positioned at rear ends of the first spool and the second spool;

wherein the control valve unit selectively applies the output signal to one or more of the first control valve and the second control valve based on whether the external air temperature value is greater than or less than the predetermined value so as to generate at least two different hydraulic load levels.

2. The multi-step regeneration apparatus of claim 1 , further comprising:

a working fluid temperature sensor configured to measure a temperature of a working fluid of the hydraulic load device,

wherein the controller compares a temperature value measured by the working fluid temperature sensor with a predetermined value and outputs a signal.

3. The multi-step regeneration apparatus of claim 1 , wherein the set pressure (P 2 ) of the second relief valve is larger than the set pressure (P 1 ) of the first relief valve.

4. The multi-step regeneration apparatus of claim 3 , wherein when the temperature value measured by the external air temperature sensor is larger than the predetermined value, the controller applies a voltage to the first control valve to open the first spool, and a pressure of a working fluid of the hydraulic load device discharged from a main pump is increased to the pressure (P 1 ) while the working fluid passes through the first relief valve.

5. The multi-step regeneration apparatus of claim 3 , wherein when the temperature value measured by the external air temperature sensor is smaller than the predetermined value, the controller applies a voltage to the first control valve and the second control valve to open the first spool and the second spool, and the pressure of a working fluid discharged of the hydraulic load device from a main pump is increased to the pressure (P 2 ) while the working fluid passes through the second relief valve.

6. The multi-step regeneration apparatus of claim 2 , wherein when the temperature value measured by the working fluid temperature sensor is larger than the predetermined value, the controller blocks a voltage applied to the first control valve and the second control valve of the control valve unit to close the control valve unit.

7. A multi-step regeneration method of a diesel particulate filter (DPF), which generates a load to an engine to remove soot, the method comprising:

measuring a temperature of external air by using an external air temperature sensor;

comparing, by a controller, a temperature value measured by the external air temperature sensor with a predetermined value and outputting a signal;

receiving the signal from the controller and selectively controlling one or more of a first control valve and a second control valve of a hydraulic load device based on whether the external air temperature value is greater than or less than the predetermined value; and

selectively increasing, by the one or more of the first control valve and the second control valve, a pressure discharged from a main pump to a set pressure (P 1 ) of a first relief valve and a set pressure (P 2 ) of a second relief valve by selectively opening one or more of a first spool and a second spool so as to generate at least two different hydraulic load levels and prevent overheating.

8. The multi-step regeneration method of claim 7 , wherein when the temperature value measured by the external air temperature sensor is larger than the predetermined value, the controller applies a voltage to the first control valve to open the first spool, and the pressure of a working fluid of the hydraulic load device discharged from the main pump is increased to the pressure (P 1 ) while the working fluid passes through the first relief valve.

9. The multi-step regeneration method of claim 7 , wherein when the temperature value measured by the external air temperature sensor is smaller than the predetermined value, the controller applies a voltage to the first control valve and the second control valve to open the first spool and the second spool, and the pressure of a working fluid of the hydraulic load device discharged from the main pump is increased to the pressure (P 2 ) while the working fluid passes through the second relief valve.