Exhaust Heat Recovery System of Vehicle and Method Thereof

Abstract

An exhaust heat recovery device may include a radiator disposed at a main line and through which hot coolant circulates, an exhaust heat exchanger transferring exhaust heat of an engine to coolant, a first valve selectively circulating the coolant to the main line or a bypass line, a water pump connected to the first valve and circulating the coolant, a coolant temperature sensor detecting temperature of the coolant, a second valve connected to the water pump and disposed at a distributing line to distribute the coolant supplied by the water pump to the engine and the exhaust heat exchanger, and a control portion that controls the first and second valves depending on the temperature of the coolant so as to adjust coolant amount circulating in the engine and the exhaust heat exchanger and coolant amount circulating in the radiator and the bypass line.

1 . An exhaust heat recovery device of a vehicle, comprising:
 a radiator that is disposed at a main line and through which hot coolant circulates so as to radiate heat thereof;   an exhaust heat exchanger that transfers exhaust heat of an engine to coolant;   a first valve that selectively circulates the coolant absorbing combustion heat of the engine to the main line or a bypass line;   a water pump connected to the first valve and circulating the coolant;   a coolant temperature sensor detecting temperature of the coolant;   a second valve that is connected to the water pump and is disposed at a distributing line to distribute the coolant supplied by the water pump to the engine and the exhaust heat exchanger; and   a control portion that controls the first and second valves depending on the temperature of the coolant detected by the coolant temperature sensor so as to adjust coolant amount circulating in the engine and the exhaust heat exchanger and coolant amount circulating in the radiator and the bypass line.   
     
     
         2 . The exhaust heat recovery device of  claim 1 , wherein the exhaust heat exchanger is disposed at a downstream side of an exhaust catalyst. 
     
     
         3 . The exhaust heat recovery device of  claim 1 , wherein the control portion controls the second valve such that the coolant amount circulating in the exhaust heat exchanger becomes larger than that of the coolant circulating in the engine when the temperature of the coolant is less than a first predetermined value. 
     
     
         4 . The exhaust heat recovery device of  claim 3 , wherein the control portion controls the first valve such that circulation of the coolant in the radiator is closed and circulation of the coolant in the bypass line is opened. 
     
     
         5 . The exhaust heat recovery device of  claim 1 , wherein the control portion controls the second valve such that the coolant amount circulating in the exhaust heat exchanger is minimized or closed and the coolant amount circulating in the engine is maximized when the coolant temperature is higher than a second predetermined value. 
     
     
         6 . The exhaust heat recovery device of  claim 5 , wherein the control portion controls the first valve such that circulation of the coolant in the radiator is opened and circulation of the coolant in the bypass line is closed. 
     
     
         7 . The exhaust heat recovery device of  claim 1 , wherein an auxiliary device is connected to the bypass line. 
     
     
         8 . An exhaust heat recovery method of a vehicle, comprising:
 detecting a temperature of a coolant and comparing the detected temperature with a first predetermined temperature value;   adjusting a passage of the coolant such that the coolant amount circulating in an exhaust heat exchanger is larger than that of the coolant circulating in an engine when the temperature of the coolant is less than the first predetermined temperature value; and   controlling the coolant such that the coolant amount circulating in the engine is larger than that of the coolant circulating the exhaust heat exchanger when the temperature of the coolant is higher than a second predetermined temperature value.   
     
     
         9 . The exhaust heat recovery method of  claim 8 , further comprising a second valve that is disposed at a distributing line connected to a water pump to distribute the coolant to the engine and the exhaust heat exchanger according to the temperature of the coolant. 
     
     
         10 . The exhaust heat recovery method of  claim 8 , further comprising:
 circulating the coolant to a bypass line when the detected temperature is lower than the first predetermined temperature value; and   circulating the coolant to a radiator when the detected temperature is higher than the second predetermined temperature value,   wherein the first predetermined temperature value is lower than the second predetermined temperature value.   
     
     
         11 . The exhaust heat recovery method of  claim 10 , further comprising a first valve connected to a water pump and selectively regulates circulation of the coolant to the bypass line and the radiator.