Urea-water solution heating and cooling devices for construction equipment

Abstract

A urea-water solution heating and cooling device for construction equipment capable of reducing nitrogen oxides in exhaust gas discharged from an engine includes: an SCR mounted on an exhaust pipe of an engine to perform a reduction process on nitrogen oxides in exhaust gas discharged along the exhaust pipe; a urea-water solution tank that stores a urea-water solution; an injector mounted on the exhaust pipe on the upstream of the SCR to inject the urea-water solution supplied from the urea-water solution tank into the exhaust pipe; a valve installed on a conduit between an engine coolant pump and the urea-water solution tank to supply engine coolant introduced from the engine coolant pump to the urea-water solution tank when being opened in order to increase the temperature of the urea-water solution in the urea-water solution tank to a set value; and a controller that opens the valve in order to supply the engine coolant to the urea-water solution tank and controls to drive a urea-water solution pump in order to supply the urea-water solution in the urea-water solution tank to the injector.

1 . A urea-water solution heating device for construction equipment, the device comprising:
 an engine including a heat exchanger and an engine coolant pump;   an SCR mounted on an exhaust pipe of the engine to perform a reduction process on nitrogen oxides in exhaust gas discharged along the exhaust pipe;   a urea-water solution tank storing a urea-water solution;   an injector mounted on the exhaust pipe at an upstream of the SCR to inject the urea-water solution, supplied from the urea-water solution tank by a urea-water solution pump, into the exhaust pipe;   a valve installed on a conduit between the engine coolant pump and the urea-water solution tank and supplying an engine coolant from the engine coolant pump to the urea-water solution tank when being opened in order to increase a temperature of the urea-water solution in the urea-water solution tank to a set value; and   a controller for controlling the valve to be opened in order to supply the engine coolant to the urea-water solution tank, and driving the urea-water solution pump to supply the urea-water solution in the urea-water solution tank to the injector.   
     
     
         2 . The urea-water solution heating device of  claim 1 , wherein the valve is a solenoid valve changing between an initial state closing the conduit and an ON state opening the conduit in response to an electrical signal applied thereto. 
     
     
         3 . The urea-water solution heating device of  claim 1 , wherein the urea-water solution tank includes:
 a temperature sensor detecting the temperature of the urea-water solution in the urea-water solution tank and outputting a detection signal to the controller.   
     
     
         4 . The urea-water solution heating device of  claim 1 , further comprising:
 a coolant channel carrying the engine coolant discharged after being heat-exchanged at the urea-water solution tank such that the heat-exchanged engine coolant is returned to the engine while passing through the urea-water solution pump so as to heat the urea-water solution pump by heat exchange with the heat-exchanged engine coolant.   
     
     
         5 . A urea-water solution heating and cooling device for construction equipment, the device comprising:
 an engine including a heat exchanger and an engine coolant pump;   an SCR mounted on an exhaust pipe of the engine to perform a reduction process on nitrogen oxides in exhaust gas discharged along the exhaust pipe;   a urea-water solution tank storing a urea-water solution;   a urea-water solution heat exchanger for performing heat exchange of an introduced engine coolant, and supplying the heat-exchanged engine coolant to the urea-water solution tank so as to lower a temperature of the urea-water solution in the urea-water solution tank to a set value;   an injector mounted on the exhaust pipe at an upstream of the SCR to inject the urea-water solution, supplied from the urea-water solution tank by a urea-water solution pump, into the exhaust pipe;   a control valve installed at a junction of a conduit between the engine coolant pump and the urea-water solution heat exchanger and a conduit between the engine coolant pump and the urea-water solution tank, and supplying a part of the engine coolant from the engine coolant pump to the urea-water solution heat exchanger or to the urea-water solution tank when the valve is switched to a position in order to correspond to the temperature of the urea-water solution in the urea-water solution tank; and   a controller for controlling the position of the control valve to be switched in order to supply the engine coolant to the urea-water solution tank or to the urea-water solution heat exchanger, and driving the urea-water solution pump to supply the urea-water solution in the urea-water solution tank to the injector.   
     
     
         6 . The urea-water solution heating and cooling device of  claim 5 , wherein the control valve includes:
 a first position closing the conduit supplying the engine coolant to the urea-water solution heat exchanger or to the urea-water solution tank when the temperature of the urea-water solution in the urea-water solution tank is maintained at the set value,   a second position supplying the engine coolant to the urea-water solution heat exchanger to perform heat exchange, and then supplying the heat-exchanged engine coolant to the urea-water solution tank when the temperature of the urea-water solution in the urea-water solution tank is higher than the set value, and   a third position supplying the engine coolant directly to the urea-water solution tank so as to increase the temperature of the urea-water solution to the set value when the temperature of the urea-water solution in the urea-water solution tank is lower than the set value.   
     
     
         7 . The urea-water solution heating and cooling device of  claim 5 , further comprising:
 a check valve being installed on a conduit between the urea-water solution heat exchanger and the urea-water solution tank and preventing heat of the engine coolant for heating the urea-water solution in the urea-water solution tank from flowing back to the urea-water solution heat exchanger.   
     
     
         8 . The urea-water solution heating and cooling device of  claim 5 , wherein the urea-water solution tank includes:
 a temperature sensor detecting the temperature of the urea-water solution in the urea-water solution tank and outputting a detection signal to the controller.   
     
     
         9 . The urea-water solution heating and cooling device of  claim 5 , wherein the urea-water solution heat exchanger is disposed in front of the heat exchanger of the engine so as to be cooled by heat exchange with outside air having a temperature lower than a temperature of outside air supplied to the heat exchanger of the engine. 
     
     
         10 . The urea-water solution heating and cooling device of  claim 5 , further comprising:
 a coolant channel carrying the engine coolant discharged after being heat-exchanged at the urea-water solution tank such that the heat-exchanged engine coolant is returned to the engine while passing through the urea-water solution pump so as to heat the urea-water solution pump by heat exchange with the heat-exchanged engine coolant.