# US 10,309,282 B2 · Reducing agent supply device and method for controlling reducing agent supply device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,309,282 B2 - Document ID: US10309282B2 - Status: Granted - Kind: B2 - Application number: 15/526,562 - Filed: 2014-12-11 - Published: 2017-11-16 - Granted: 2019-06-04 - Earliest claimed: 2014-12-11 - Assignees: Komatsu Ltd. - Applicants: Komatsu Ltd. - Inventors: Hirofumi Kizawa - Web page: https://patentgrep.com/patent/US10309282B2 ## CPC - F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent} - F01N 3/0821: {combined with particulate filter} - F01N 11/005: {the temperature or pressure being estimated, e.g. by means of a theoretical model} - F02B 37/12: Control of the pumps - F02D 41/0275: {the exhaust gas treating apparatus being a NOx trap or adsorbent} - F02D 41/042: {for stopping the engine} - F01N 2550/05: Systems for adding substances into exhaust - F01N 2610/02: the substance being ammonia or urea - F01N 2610/144: Control thereof - F01N 2610/1493: Purging the reducing agent out of the conduits or nozzle - F01N 2900/08: said parameters being related to the engine - F01N 2900/1808: Pressure - F01N 2900/1818: Concentration of the reducing agent - F01N 2900/1822: Pump parameters - Y02T 10/12: Improving ICE efficiencies - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A reduction-causing agent supply device includes a tank to store a reduction-causing agent, a pumping unit to pump the reduction-causing agent, a reduction-causing agent supply passage to supply the reduction-causing agent, an injection nozzle to inject the reduction-causing agent into an exhaust pipe, a drawing-back unit to draw the reduction-causing agent toward the tank, and a controller. After stop of an engine, the controller performs: reduction-causing agent drawing-back process of drawing the reduction-causing agent toward the tank and introducing exhaust gas from the injection nozzle into the reduction-causing agent supply passage; and gas discharge process of supplying the reduction-causing agent to compress the exhaust gas inside the reduction-causing agent supply passage, discharging the compressed exhaust gas from the injection nozzle, and closing a valve of the injection nozzle before the reduction-causing agent reaches the injection nozzle. ## Claims ### Claim 1 A reduction-causing agent supply device, comprising: a tank configured to store a reduction-causing agent to be supplied into an exhaust pipe of an engine; a pumping unit comprising a pump configured to pump the reduction-causing agent stored in the tank; a reduction-causing agent supply passage configured to supply the pumped reduction-causing agent; an injection nozzle configured to inject the reduction-causing agent supplied through the reduction-causing agent supply passage into the exhaust pipe; a drawing-back unit comprising the pump and a switching valve and being configured to draw back the reduction-causing agent present inside the reduction-causing agent supply passage toward the tank; and a controller configured to control an operation of each of the pumping unit, the injection nozzle and the drawing-back unit, wherein the controller is configured to perform a reduction-causing agent drawing-back process and a compressed gas discharge process, after the engine is stopped, wherein in the reduction-causing agent drawing-back process; the controller is configured to operate the drawing-back unit, while a valve of the injection nozzle is closed, to draw back the reduction-causing agent present inside the reduction-causing agent supply passage toward the tank; and operate the drawing-back unit, while the valve of the injection nozzle is open, to introduce gas present inside the exhaust pipe into the injection nozzle and the reduction-causing agent supply passage, and in the compressed gas discharge process; the controller is configured to operate the pumping unit, while the valve of the injection nozzle is closed, to supply the reduction-causing agent into the reduction-causing agent supply passage to compress the gas introduced in the reduction-causing agent supply passage; open the valve of the injection nozzle to discharge the compressed gas into the exhaust pipe through the injection nozzle; and close the valve of the injection nozzle before the reduction-causing agent present inside the reduction-causing agent supply passage reaches the injection nozzle while the pump is kept in operation. ### Claim 2 (depends on 1) The reduction-causing agent supply device according to claim 1, wherein in the reduction-causing agent drawing-back process; the controller is configured to operate the drawing-back unit, while the valve of the injection nozzle is closed, to draw back the reduction-causing agent present inside the reduction-causing agent supply passage toward the tank; at an elapse of a predetermined first set time after the drawing-back unit starts to be operated, open the valve of the injection nozzle to introduce the gas present inside the exhaust pipe into the injection nozzle and the reduction-causing agent supply passage; at an elapse of a predetermined second set time after the drawing-back unit starts to be operated, stop the drawing-back unit; and at an elapse of a predetermined third set time after the drawing-back unit starts to be operated, close the valve of the injection nozzle, and in the compressed gas discharge process; the controller is configured to operate the pumping unit, while the valve of the injection nozzle is closed, to supply the reduction-causing agent into the reduction-causing agent supply passage to compress the gas introduced in the reduction-causing agent supply passage; at an elapse of a predetermined fourth set time after the pumping unit starts to be operated, open the valve of the injection nozzle to discharge the compressed gas into the exhaust pipe through the injection nozzle, and at an elapse of a predetermined fifth set time after the pumping unit starts to be operated, close the valve of the injection nozzle. ### Claim 3 (depends on 1) The reduction-causing agent supply device according to claim 1, further comprising: a pressure gauge configured to measure a pressure in the reduction-causing agent supply passage, wherein in the reduction-causing agent drawing-back process, the controller is configured to operate the drawing-back unit, while the valve of the injection nozzle is closed, to draw back the reduction-causing agent present inside the reduction-causing agent supply passage toward the tank; when a value measured by the pressure gauge reaches a predetermined first pressure value after the drawing-back unit starts to be operated, open the valve of the injection nozzle to introduce the gas present inside the exhaust pipe into the injection nozzle and the reduction-causing agent supply passage; when the value measured by the pressure gauge reaches a predetermined second pressure value higher than the first pressure value, stop the drawing-back unit; and when the value measured by the pressure gauge reaches a predetermined third pressure value higher than the second pressure value, close the valve of the injection nozzle, and in the compressed gas discharge process; the controller is configured to operate the pumping unit, while the valve of the injection nozzle is closed, to supply the reduction-causing agent into the reduction-causing agent supply passage to compress the gas introduced in the reduction-causing agent supply passage; when the value measured by the pressure gauge reaches a predetermined fourth pressure value higher than the third pressure value, open the valve of the injection nozzle to discharge the compressed gas into the exhaust pipe through the injection nozzle, and when the value measured by the pressure gauge reaches a predetermined fifth pressure value higher than the third pressure value and lower than the fourth pressure value, close the valve of the injection nozzle. ### Claim 4 (depends on 3) The reduction-causing agent supply device according to claim 3, wherein the first pressure value, the second pressure value, the third pressure value, the fourth pressure value and the fifth pressure value are values calculated based on an inner diameter and a length of the reduction-causing agent supply passage, a volume of each of the pumping unit and the drawing-back unit, and a volume of the injection nozzle. ### Claim 5 (depends on 1) The reduction-causing agent supply device according to claim 1, wherein after the engine is stopped, the controller is configured to repeat the reduction-causing agent drawing-back process and the compressed gas discharge process for a plurality of times and subsequently perform the reduction-causing agent drawing-back process. ### Claim 6 A control method of a reduction-causing agent supply device comprising: a tank configured to store a reduction-causing agent to be supplied into an exhaust pipe of an engine; a pumping unit comprising a pump configured to pump the reduction-causing agent stored in the tank; a reduction-causing agent supply passage configured to supply the pumped reduction-causing agent; an injection nozzle configured to inject the reduction-causing agent supplied through the reduction-causing agent supply passage into the exhaust pipe; a drawing-back unit comprising the pump and a switching valve and being configured to draw back the reduction-causing agent present inside the reduction-causing agent supply passage toward the tank, the control method comprising: after the engine is stopped, operating the drawing-back unit, while a valve of the injection nozzle is closed, to draw back the reduction-causing agent present inside the reduction-causing agent supply passage toward the tank; operating the drawing-back unit, while the valve of the injection nozzle is open, to introduce gas present inside the exhaust pipe into the injection nozzle and the reduction-causing agent supply passage; operating the pumping unit, while the valve of the injection nozzle is closed, to supply the reduction-causing agent into the reduction-causing agent supply passage to compress the gas introduced in the reduction-causing agent supply passage; opening the valve of the injection nozzle to discharge the compressed gas into the exhaust pipe through the injection nozzle, and closing the valve of the injection nozzle before the reduction-causing agent present inside the reduction-causing agent supply passage reaches the injection nozzle while the pump is kept in operation. ### Claim 7 A reduction-causing agent supply device, comprising: a tank configured to store a reduction-causing agent to be supplied into an exhaust pipe of an engine; a pumping unit comprising a discharging pump configured to pump the reduction-causing agent stored in the tank; a reduction-causing agent supply passage configured to supply the pumped reduction-causing agent; an injection nozzle configured to inject the reduction-causing agent supplied through the reduction-causing agent supply passage into the exhaust pipe; a drawing-back unit comprising a drawing-back pump configured to draw back the reduction-causing agent present inside the reduction-causing agent supply passage toward the tank; and a controller configured to control an operation of each of the pumping unit, the injection nozzle and the drawing-back unit, wherein the controller is configured to perform a reduction-causing agent drawing-back process and a compressed gas discharge process, after the engine is stopped, wherein in the reduction-causing agent drawing-back process; the controller is configured to operate the drawing-back unit, while a valve of the injection nozzle is closed, to draw back the reduction-causing agent present inside the reduction-causing agent supply passage toward the tank; and operate the drawing-back unit, while the valve of the injection nozzle is open, to introduce gas present inside the exhaust pipe into the injection nozzle and the reduction-causing agent supply passage, and in the compressed gas discharge process; the controller is configured to operate the pumping unit, while the valve of the injection nozzle is closed, to supply the reduction-causing agent into the reduction-causing agent supply passage to compress the gas introduced in the reduction-causing agent supply passage; open the valve of the injection nozzle to discharge the compressed gas into the exhaust pipe through the injection nozzle; and close the valve of the injection nozzle before the reduction-causing agent present inside the reduction-causing agent supply passage reaches the injection nozzle while the discharging pump is kept in operation. ### Claim 8 (depends on 7) The reduction-causing agent supply device according to claim 7, wherein in the reduction-causing agent drawing-back process; the controller is configured to operate the drawing-back unit, while the valve of the injection nozzle is closed, to draw back the reduction-causing agent present inside the reduction-causing agent supply passage toward the tank; at an elapse of a predetermined first set time after the drawing-back unit starts to be operated, open the valve of the injection nozzle to introduce the gas present inside the exhaust pipe into the injection nozzle and the reduction-causing agent supply passage; at an elapse of a predetermined second set time after the drawing-back unit starts to be operated, stop the drawing-back unit; and at an elapse of a predetermined third set time after the drawing-back unit starts to be operated, close the valve of the injection nozzle, and in the compressed gas discharge process; the controller is configured to operate the pumping unit, while the valve of the injection nozzle is closed, to supply the reduction-causing agent into the reduction-causing agent supply passage to compress the gas introduced in the reduction-causing agent supply passage; at an elapse of a predetermined fourth set time after the pumping unit starts to be operated, open the valve of the injection nozzle to discharge the compressed gas into the exhaust pipe through the injection nozzle, and at an elapse of a predetermined fifth set time after the pumping unit starts to be operated, close the valve of the injection nozzle. ### Claim 9 (depends on 7) The reduction-causing agent supply device according to claim 7, further comprising: a pressure gauge configured to measure a pressure in the reduction-causing agent supply passage, wherein in the reduction-causing agent drawing-back process, the controller is configured to operate the drawing-back unit, while the valve of the injection nozzle is closed, to draw back the reduction-causing agent present inside the reduction-causing agent supply passage toward the tank; when a value measured by the pressure gauge reaches a predetermined first pressure value after the drawing-back unit starts to be operated, open the valve of the injection nozzle to introduce the gas present inside the exhaust pipe into the injection nozzle and the reduction-causing agent supply passage; when the value measured by the pressure gauge reaches a predetermined second pressure value higher than the first pressure value, stop the drawing-back unit; and when the value measured by the pressure gauge reaches a predetermined third pressure value higher than the second pressure value, close the valve of the injection nozzle, and in the compressed gas discharge process; the controller is configured to operate the pumping unit, while the valve of the injection nozzle is closed, to supply the reduction-causing agent into the reduction-causing agent supply passage to compress the gas introduced in the reduction-causing agent supply passage; when the value measured by the pressure gauge reaches a predetermined fourth pressure value higher than the third pressure value, open the valve of the injection nozzle to discharge the compressed gas into the exhaust pipe through the injection nozzle, and when the value measured by the pressure gauge reaches a predetermined fifth pressure value higher than the third pressure value and lower than the fourth pressure value, close the valve of the injection nozzle. ### Claim 10 (depends on 9) The reduction-causing agent supply device according to claim 9, wherein the first pressure value, the second pressure value, the third pressure value, the fourth pressure value and the fifth pressure value are values calculated based on an inner diameter and a length of the reduction-causing agent supply passage, a volume of each of the pumping unit and the drawing-back unit, and a volume of the injection nozzle. ### Claim 11 (depends on 7) The reduction-causing agent supply device according to claim 7, wherein after the engine is stopped, the controller is configured to repeat the reduction-causing agent drawing-back process and the compressed gas discharge process for a plurality of times and subsequently perform the reduction-causing agent drawing-back process.