Cooling apparatus for internal combustion engine

Abstract

A cooling apparatus for an internal combustion engine includes: a coolant pump; coolant piping provided so that a first coolant circuit and a second coolant circuit are arranged in a parallel manner; a heat radiation mechanism of the coolant; a load mechanism operated using heat carried by the coolant; an exhaust heat recovery device, disposed in an exhaust pipe of the internal combustion engine, that perform heat exchange between the coolant flowing through the second coolant circuit and exhaust gas from the internal combustion engine; and a flow control unit that controls a flow rate of the coolant in accordance with a temperature of the coolant in a disposition portion at which the flow control unit is disposed, the flow control unit being disposed downstream of the exhaust heat recovery device on the second coolant circuit.

1 . A cooling apparatus for an internal combustion engine, comprising:
 a coolant pump that circulates a coolant in the internal combustion engine;   coolant piping provided in a manner such that an operation of the coolant pump produces a first coolant circuit and a second coolant circuit that are arranged in a parallel manner;   a heat radiation mechanism that is disposed on the first coolant circuit and radiates heat from the coolant;   a load mechanism that is disposed on the second coolant circuit and is operated using heat carried by the coolant;   an exhaust heat recovery device that is disposed in an exhaust pipe of the internal combustion engine and performs heat exchange between the coolant flowing through the second coolant circuit and exhaust gas discharged from the internal combustion engine; and   a flow control unit that controls a flow rate of the coolant in accordance with a temperature of the coolant which flows into the flow control unit, the flow control unit being disposed downstream of the exhaust heat recovery device on the second coolant circuit.   
   
   
       2 . The cooling apparatus according to  claim 1 , wherein:
 when the temperature of the coolant is within a first temperature range which is below a first predetermined temperature, the flow rate of the coolant is not limited by the flow control unit;   when the temperature of the coolant is within a second temperature range which is between the first predetermined temperature and a second predetermined temperature inclusive, the flow control unit reduces the flow rate of the coolant; and   when the temperature of the coolant is within a third temperature range which is above the second predetermined temperature, the flow control unit increases the flow rate of the coolant compared to the flow rate in the second temperature range.   
   
   
       3 . The cooling apparatus according to  claim 1 , wherein:
 the flow control unit includes a thermal deformation member that expands and contracts in accordance with the temperature of the coolant and movable portion that is displaced as the thermal deformation member expands and contacts; and   the flow control unit opens and doses a coolant passage on the second coolant circuit by the thermal deformation member and the movable portion.   
   
   
       4 . The cooling apparatus according to  claim 3 , wherein the movable portion is provided with a flow limiter that closes the coolant passage when the movable portion is displaced within a predetermined range. 
   
   
       5 . The cooling apparatus according to  claim 4 , wherein the flow limiter is provided with at least one penetration hole through which a predetermined amount of the coolant is passed even when the coolant passage is closed. 
   
   
       6 . The cooling apparatus according to  claim 3 , wherein the thermal deformation member contains a wax material. 
   
   
       7 . The cooling apparatus according to  claim 3 , wherein the thermal deformation member is made of a shape-memory alloy. 
   
   
       8 . The cooling apparatus according to  claim 1 , wherein the flow control unit includes: a temperature detection device that detects the temperature of the coolant; a flow control valve whose opening degree is controlled based on an electric signal; and a control portion that generates the electric signal to control the opening degree of the flow control valve in accordance with the detected temperature of the coolant. 
   
   
       9 . The cooling apparatus according to  claim 1 , wherein:
 the exhaust heat recovery device and the flow control unit are disposed in series on the second coolant circuit; and   the load mechanism is disposed in parallel to the exhaust heat recovery device and the flow control unit.   
   
   
       10 . The cooling apparatus according to  claim 1 , wherein:
 the exhaust heat recovery device includes: a first exhaust passage on which the heat exchange is performed between the coolant and the exhaust gas; a second exhaust passage by which the first exhaust passage is bypassed; and an exhaust control valve that controls a proportion of a flow rate of exhaust gas that flows through the first exhaust passage with respect to a flow rate of the exhaust gas that flows through a second exhaust passage; and   the exhaust control valve is controlled so that the exhaust gas mainly flows through the second exhaust passage when the temperature of the coolant is in a temperature range in which the flow rate of the coolant is limited by the flow control unit.   
   
   
       11 . The cooling apparatus according to  claim 1 , wherein the load mechanism is a heater.