Abstract:
The present invention relates to a cooling controller for cooling an internal-combustion engine such as an internal-combustion engine for an automobile, comprising a temperature detector for detecting the temperature of the cooling medium placed in a first or second circulation channel, and a flow control for controlling the flow of the cooling medium placed in the first or second circulation channel. 
     The first circulation channel passes through the engine and the radiator as in a conventional cooling system. The second circulation channel, which is used in case of a detected failure of the radiator or thermostat valve, includes the heat exchanger of the automobile&#39;s air-conditioning system. When the failure is detected an air conditioner controller maximizes the amount of heat radiated from the air conditioning exchanger to prevent overheating.

Description:
This is a divisional of application Ser. No. 09/787,026 filed Mar. 13, 2001; the disclosure of which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a cooling controller for cooling an internal-combustion engine such as an internal-combustion engine for an automobile, and particularly to a cooling controller for an internal-combustion engine that can prevent an internal-combustion engine from overheating in the case where the thermostat or other parts may fail. 
     BACKGROUND OF THE INVENTION 
     In an internal-combustion engine (hereinafter abbreviated as “engine”) for use in an automobile, a water-cooled type cooling device using a heat exchanger (hereinafter referred to as “radiator”) for cooling the engine has been utilized. In such a cooling device, a thermostat is utilized as a cooling control means to control the temperature of the cooling water. If the temperature of the cooling water is lower than a designated temperature, the thermostat is closed so the cooling water circulates within a bypass route, not through the radiator. If the cooling water becomes higher than a designated temperature, the thermostat is opened and the cooling water circulates within the radiator. 
     The conventional cooling controller for an internal-combustion engine is shown in FIG.  7 . In the cooling controller  100  for an internal-combustion engine in this figure, a fluid passage shown by the arrow is formed within an engine E composed of a cylinder head  101   a  and a cylinder block  101   b . Further, a cooling water channel  102  for circulating the cooling water is placed between the engine E and radiator R. 
     The cooling water channel  102  is composed of a cooling water channel  102   a  connecting an outlet for the cooling water provided at an upper portion of the engine E with an inlet of the radiator R, a cooling water channel  102   b  provided from an outlet of the radiator R to an inlet for the cooling water provided at a lower portion of the engine E, and a bypass channel  103  which connects the cooling water channel  102   a  at the outlet side to the cooling water channel  102   b  at the inlet side. A thermostat  104  is placed on a branch portion between the cooling water channel  102   a  at the outlet side and the bypass channel  103 . The thermostat  104  embeds a heat responding element, which expands or shrinks due to changes in the heat, like a wax does. When the temperature of the cooling water is high, the valve is opened by the expansion of the heat responding element to allow the cooling water flowing from the engine E to enter into the radiator R via the cooling water channel  102   a  at the side of the outlet, and the cooling water having a low temperature due to the heat radiation by the radiator R passes through the bypass channel  103  to flow into the cooling channel within the engine E from the inlet of the engine E. 
     When the temperature of the cooling water is low, the valve of the thermostat  104  is closed due to the shrinkage of the heat responding element, and the cooling water flowing from the outlet of engine E passes through the bypass channel  103  to enter from the inlet of the engine E into the cooling channel within the engine E. 
     A water pump WP is placed at the inlet of the engine E, and by the rotation of a crankshaft (not shown) of the engine E, the rotation shaft of the pump is rotated, forcing the cooling water to be circulated. In addition, the radiator R is provided with a cooling fan  105  for forcible intake of the cooling air, and is composed of a cooling fan  105  and a fan motor  106  for rotating the cooling fan  105 . 
     The conventional cooling device described above has the following problems: when the fan motor  106  of the cooling fan  105  in the radiator R has a problem, or any problem occurs in the thermostat  104  such as the valve being left closed so the cooling water does not circulate into the radiator R, the cooling water is not cooled. Consequently, the engine E attains a state of overheating. 
     A cooling controller for an internal-combustion engine according to the present invention has been made in light of the above situation, and provides a system which can prevent problems such as overheating, even if the radiator or the thermostat has failed and which can exhibit fail-safe functions. 
     SUMMARY OF THE INVENTION 
     A cooling controller for a internal-combustion engine according to the present invention which solves the problems described above, includes: 
     a first heat exchanger configured by forming a circulation channel for a cooling medium between an internal-combustion engine and a heat exchanger to radiate out heat generated in the internal-combustion engine through circulation of the cooling medium, and a second heat exchanger which radiates out heat by forming a second circulation channel for air conditioning an automobile cabin, the cooling controller further comprising: 
     a temperature detecting means to detect the temperature of said cooling medium, wherein the temperature detecting means is placed in at least one of said first or second circulation channels, 
     a flow amount control means to control the flow amount of said cooling medium, 
     a driving condition detecting means for said internal-combustion engine, 
     an internal-combustion engine control means to control said internal-combustion engine based on the output signal from said driving condition detecting means, 
     an air conditioner for air conditioning the automobile cabin utilizing the heat radiation of said second heat exchanging system, 
     an air conditioner control means to control said air conditioner, and 
     said air conditioner control means outputting an operating signal which maximizes an amount of heat radiated from said second heat exchanger for air conditioning when an abnormality of the cooling function of said internal-combustion engine is detected by said input signal from said internal-combustion engine control means. 
     A cooling controller having such a configuration can allow the cooling medium to cool down through the second heat exchanger, even if said first heat exchanger or said flow amount control means is defective and does not allow the cooling medium to cool down, making it possible to take precautions against serious problems such as overheating. 
     Furthermore, said flow amount control means is preferably characterized by opening or closing the thermostat valve through an input signal from said internal-combustion engine control means. 
     The flow amount control means can carefully control the angle of the valve and, thus, the flow amount in said first circulation channel can be controlled with high reliability. 
     The present invention also relates to a cooling controller for an internal-combustion engine comprising: 
     a first heat exchanger configured by forming a circulation channel for a cooling medium between an internal-combustion engine and a heat exchanger to radiate out heat generated in the internal-combustion engine through circulation of the cooling medium, and a second heat exchanger which radiates out heat by forming a second circulation channel for air-conditioning an automobile cabin, which cooling controller further comprises: 
     a temperature detecting means to detect the temperature of said cooling medium, wherein the temperature detecting means is placed in at least one of said first or second circulation channels, 
     a flow amount control means to control the flow of said cooling medium, 
     an air conditioner for air conditioning the automobile cabin having said second heat exchanger and carrying out air conditioning utilizing the cooling medium of said internal-combustion engine, 
     an air conditioner control means to control said air conditioner, and 
     said air conditioner control means outputting an operating signal which maximizes an amount of heat radiated out from said second heat exchanger when the input signal from said temperature detecting means is higher than a designated temperature. 
     The flow amount control means is preferably a thermostat which opens or closes a valve by means of a thermal expansion means embedded in a casing. 
     A cooling controller for an internal-combustion engine having such a configuration has a relatively simple configuration, and can automatically open or close the circulation channel of said cooling medium. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a drawing showing a cooling controller for an internal-combustion engine according to a first embodiment of the present invention; 
     FIG. 2 is a cross-sectional view showing a thermostatic valve for use in the cooling controller of FIG. 1; 
     FIG. 3 is a drawing showing an air conditioner for use in the cooling controller of FIG. 1; 
     FIG. 4 is a drawing showing a cooling controller for an internal-combustion engine according to a second embodiment of the present invention; 
     FIG. 5 is a cross-sectional view showing a thermostat for use in the cooling controller of FIG. 4; 
     FIG. 6 is a drawing showing functions of an air conditioner control means for use in the cooling controller of FIG. 4; and 
     FIG. 7 is a drawing showing a cooling controller for an internal-combustion engine according to the prior art. 
    
    
     Descriptions of parts which are the same as those of the conventional device are omitted. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A cooling controller for an internal-combustion engine according to a first embodiment of the present invention will now be described by referring to FIGS. 1 to  3 . 
     In a cooling controller A for an internal-combustion engine shown in FIG. 1, a first circulation channel  1  for cooling fluid W, which is a cooling medium, is formed between a fluid channel formed in an engine E, which is an internal-combustion engine, and a fluid channel formed in a radiator R, which is a heat exchanger. By circulating the cooling fluid W in the first circulation channel, heat generated in the engine E is radiated out through the radiator R. Further, a second circulation channel  2 , which is branched off the first circulation channel  1 , is formed, and a heater core  21 , which is a second heat exchanger and which is used for air conditioning of an automobile cabin, is provided in the circulation channel  2 . It will be understood that the type of air conditioning of an automobile cabin provided by the second heat exchanger is heating. A bypass channel BC is also provided to allow cooling fluid W to flow in the first circulation channel  1  while bypassing the radiator R. 
     A cooling fluid temperature sensor  3 , which detects the temperature of the cooling fluid W, and which is a temperature detecting means, is placed adjacent to the portion connecting the engine E to the first or second circulation channel. The cooling fluid temperature sensor  3  detects the fluid temperature by the use, e.g., of a thermistor, etc., and the temperature detected by the cooling fluid temperature sensor  3  is converted into an electrical output signal and is output to the engine control unit ECU, which is the internal-combustion engine control means. 
     At the channel portion between the channel branch  6  of the first circulation channel  1 , the bypass channel BC, and the channel branch  6  leading to the fluid pump WP, a thermostatic valve  10  is provided as a variable flow control means which controls the flow of the cooling fluid W. The thermostatic valve  10  controls the flow degree of the cooling fluid W by opening or closing an internal valve through an electric control, as described more fully later on. The opening and closing of the valve is controlled by the engine control unit ECU. 
     At the connecting portion of the inlet  1   a  of the first circulation channel  1  to the engine E, a fluid pump WP for circulating the cooling fluid W is provided. The fluid pump WP is a gear pump driven by the engine E, and cools the engine E by passing the cooling fluid W through a fluid channel formed within the engine E, and circulates the cooling fluid W into the fluid channel of the radiator R via an output  1   b  of the circulation channel  1 . The cooling fluid W circulated into the radiator R is cooled down by cooling air, which is suctioned by the radiator fan  4 , and the cooling fluid W having been cooled is transferred to the engine E via the inlet  1   a  of the first circulation channel  1 . The radiator fan  4  is an electric fan which is driven by a motor  5 , and the flow amount of air and ON-OFF switching are controlled depending upon the temperature of the cooling fluid W. The control is carried out by the engine control unit ECU based on the temperature of the cooling fluid W detected by the cooling fluid temperature sensor  3 . 
     As shown in FIG. 2, the thermostatic valve  10  to be used in the cooling controller A for an internal-combustion engine is configured so that a valve body having a 3-way configured valve  11 , having vanes  11   a  and  11   b , is placed between the inlet  1   a , the bypass channel BC, and the channel branch  6  leading to the fluid pump WP, and the shaft  12  of the 3-way configured valve  11  is driven by a drive motor  14  via a deceleration mechanism  13  to open or close the 3-way configured valve  11 . In the embodiment shown in FIG. 2, vane  11   a  opens to allow flow from inlet  1   a  to channel branch  6  as vane  11   b  closes to cut off flow from bypass channel BC to channel branch  6 , and vice versa. Between the deceleration mechanism  13  and the drive motor  14 , an electronic clutch  15  is placed so as to break off the rotation of the drive motor  14 . Between the valve body and the deceleration mechanism  13 , a return spring  16  is equipped to apply a resilient force against the 3-way configured valve  11  in a direction so that the 3-way configured valve  11  returns to a fail-safe normal position. 
     The thermostatic valve  10  configured as described above is controlled by the engine control unit ECU, so that when the temperature of the cooling fluid W is less than a designated temperature, the valve is maintained in a position that bypasses the radiator R, and when it is higher than a designated temperature, the valve is positioned at an adequate angle depending upon the cooling fluid temperature to allow a variable flow of cooling fluid W through the radiator R. 
     The engine control unit ECU, which controls the thermostatic valve  10  and the radiator R as well as the driving state on the whole, and which includes a microcomputer, keeps the driving conditions of the engine E under control by inputting data on the rotation speed of the Engine E, the degree of opening of the throttle, and other parameters through various driving condition sensors DCS, the cooling fluid temperature sensor  3 , as well as other sensors OS, and outputs a control signal to each of the control devices to maintain the most ideal driving conditions. 
     An air conditioner AC which controls a heater core  21 , which is the second heat exchanger, based on an output signal from the engine control unit ECU will now be described by referring to FIG.  3 . In this figure, the air conditioner AC is composed of the body  20  of the device and a control part  30  for controlling air conditioning, which controls the body  20  of the device. 
     In the body  20  of the device, the heater core  21  is placed in the circulation channel  2 , and heat exchange is carried out by passing the cooling fluid W through the heater core  21 . For this reason, a blower fan  22  is placed at the heater core  21 , and by controlling the speed of the blower fan  22 , the amount of heat radiated out can be controlled. 
     An air mix door  23  is also placed on the body  20  of the device for the purpose of mixing the hot air transferred from the heater core  21  with the cooling fluid W for controlling the temperature. The air mix door  23  actuates to a given position according to the set temperature by means of an air mix door actuator  23   a  based on control by the control part  30  for controlling the air conditioning. Further, an air blowing mode door  24  switches the air, controlled to a designated temperature at the air mix door  23 , into an air blowing mode such as DEF, VENT, or FOOT, and is actuated by means of an air blowing mode actuator  24   a  through control by control part  30  for controlling the air conditioning. 
     The body  20  of the device further possesses an evaporator  25  for forming cooling air for air conditioning. The evaporator  25  is driven by an outdoor unit  25   a  for the air conditioner through a control signal of the control part  30 . 
     Also, an intake door  26  for switching intake of the air from inside or outside of the automobile cabin is placed on the body  20  of the device. The intake door  26  has a configuration so as to be actuated by means of an intake door actuator  26   a  based on a control signal from control part  30 . 
     The control part  30  has a microcomputer etc., and drives the body  20  of the device according to an input signal input from an operation panel  31  placed on a dashboard, etc., in the automobile cabin. On the operation panel  31  are placed an air conditioning switch  31   a , which turns the air conditioner AC ON or OFF, a mode switch  31   b  which switches the air-blowing mode to DEF, VENT, or FOOT, an intake switch  31   c  which switches intake of the air from inside or outside of the automobile cabin, a temperature control switch  31   d , which controls the set temperature, and a display unit  31   e  for displaying the contents set by these switches. Further, the control part  30  controls the blower fan  22 , the air mix door  23 , the air-blowing mode door  24 , the intake door  26 , etc., to desired operating points by comparing the conditions set at the operation panel  31  with the present temperature input from various temperature sensors  32 , such as the external atmospheric temperature sensor  32   a , the internal atmospheric temperature sensor  32   b , and the solar sensor  32   c.    
     Further, the control part  30  is configured so as to input the output signal from the engine control unit ECU. The output signal from the engine control unit ECU is configured so that it is output when any defect of the radiator fan  4  or the thermostatic valve  10  shown in FIG. 1 occurs, making the cooling fluid temperature at the cooling fluid temperature sensor  3  abnormal. In control part  30 , when an abnormal signal is input from the engine control unit ECU, the blower fan  22  rotates at the maximum speed to maximize the heat radiation from the heater core  21 . The control part  30  is configured so that when an abnormal signal is input from the engine control unit ECU, the occurrence of abnormality appears on the display unit  31   e  of the display panel  31 . 
     The cooling controller A configured as described above makes it possible to cool the cooling fluid W by radiating out heat through the heater core  21 , even if the radiator fan  4  or the thermostatic valve  10  has a problem. Furthermore, a driver can deal with the abnormality in an adequate manner based on the display of the occurrence of the abnormality on the display unit  31   e , thereby preventing problems ahead of time. 
     A cooling controller for an internal-combustion engine according to a second embodiment of the present invention will now be described by referring to FIGS. 4 to  6 . Parts which are the same as those of the cooling controller A are represented by the same symbols. 
     In a cooling controller B for an internal-combustion engine shown in FIG. 4, a first circulation channel  1  for cooling fluid W, which is a cooling medium, is formed between a fluid channel formed in an engine E, which is an internal-combustion engine, and a fluid channel formed in a radiator R, which is a heat exchanger. By circulating the cooling fluid W in the first circulation channel, heat generated in the engine E is radiated through the radiator R. Further, a second circulation channel  2  which is branched off the first circulation channel  1 , is formed, and a heater core  51 , which is a second heat exchanger and which is used for air conditioning an automobile cabin, is provided in the circulation channel  2  for air conditioning. A bypass channel BC is also provided to allow cooling fluid W to flow in the first circulation channel  1  while bypassing the radiator R. 
     In cooling controller B a cooling fluid temperature sensor  3 , which detects the temperature of the cooling fluid W, and which is a temperature detecting means is placed adjacent to the portion connecting the engine E to the first or second circulation channel. The cooling fluid temperature sensor  3  detects the cooling fluid temperature by the use of an, e.g., thermistor, etc., and the temperature detected by the cooling fluid temperature sensor  3  is converted into an electrical output signal and is output to the control part  60 . 
     At the channel portion between the inlet  1   a  of the first circulation channel  1 , the bypass channel BC and the channel branch  6  leading to the fluid pump WP, a thermostat  40  is provided as a variable flow control means which controls the flow of the cooling fluid W. The thermostat  40  includes a heat responding element  44  and opens or closes valves  42  and  48  depending on the cooling fluid temperature to control the flow amount of the cooling fluid W, as described later on. 
     At the connecting portion of the inlet  1   a  of the first circulation channel  1  to the engine E, a fluid pump WP for circulating cooling fluid W is provided. The fluid pump WP is a gear pump driven by the engine E, and cools the engine E by passing the cooling fluid W through a fluid channel formed within the engine E, and circulates the cooling fluid W into the fluid channel of the radiator R via an output  1   b  of the circulation channel  1 . The cooling fluid W circulated into the radiator R is cooled down by cooling air, which is suctioned by the radiator fan  4 , and the cooling fluid W having been cooled is transferred to the engine E via the inlet la of the first circulation channel  1 . The radiator fan  4  is an electric fan which is driven by a motor  5 , and the air amount is automatically controlled depending upon the temperature of the cooling fluid W. 
     As shown in FIG. 5, the thermostat  40  which is used in the cooling controller B is placed at the channel portion between the first circulation channel  1 , the bypass channel BC, and the channel branch  6  leading to the fluid pump WP. The movable valve  42  is placed within a frame  41  fixed on the wall of the circulation channel, and the valve  42  opens or closes the inlet la from the radiator R. The movable valve  48  is attached to a casing  46  of a thermo element  43  which is stored within the frame  41 , and the valve  48  opens or closes the inlet from the bypass channel BC. When the heat responding element  44  embedded in the thermo element  43  pushes the valves  42  and  48  by heat expansion, the cooling fluid W is gradually allowed to pass through the radiator R, and is eventually substantially prevented from flowing through the bypass channel BC. Specifically, when the heat responding element  44  thermally expands, a piston rod  45  is pushed up, but since the end portion of the piston rod  45  is held by the frame  41 , the casing  46  of the thermo element  43  is conversely pushed down. For this reason, a push plate  47  pushes the valve  42  down to make a gap between the valve  42  and the frame  41 , and causes the valve  48  to seal off the inlet of the bypass channel BC. The cooling fluid W is then routed through the radiator and substantially prevented from flowing through the bypass channel BC. 
     The thermostat  40  configured as described above is set so as to keep the valve in a closed state with respect to the radiator R so cooling fluid W does not flow through the radiator R when the temperature of the cooling fluid W is less than a designated temperature, and to open the valve with respect to the radiator R so cooling fluid W does flow through the radiator R when the temperature of the cooling fluid W is higher than a designated temperature. 
     Next, an air conditioner AC will now be described by referring to FIG.  6 . In this figure, the air conditioner AC is composed of the body  50  of the device and a control part  60  for controlling the air conditioning, which controls the body  50  of the device. 
     In the body  50  of the device, the heater core  51  is placed in the circulation channel  2 , and heat exchange is carried out by passing the cooling fluid W through the heater core  51 . For this reason, a blower fan  52  is placed on the heater core  51 , and by controlling the speed of the blower fan  52 , the amount of heat radiated out can be controlled. 
     An air mix door  53  is also placed on the body  50  of the device for the purpose of mixing the hot air transferred from the heater core  51  with the cooling fluid W for controlling the temperature. The air mix door  53  is actuated to a given position according to the set temperature by means of an air mix door actuator  53   a , based on control by the control part  60 . Further, an air blowing mode door  54  switches the air controlled to a designated temperature at the air mix door  53  into an air blowing mode such as DEF, VENT, or FOOT, and is actuated by means of an air blowing mode actuator  54   a  through control by control part  60  for controlling the air conditioning. 
     The body  50  of the device further possesses an evaporator  55  for forming cooling air for air conditioning. The evaporator  55  is driven by an outdoor unit  55   a  through a control signal of the control part  60 . 
     Also, an intake door  56  for switching the intake of air from inside or outside of the automobile cabin is placed on the body  50  of the device. The intake door  56  has such a configuration so as to be actuated by means of an intake door actuator  56   a  based on a control signal from control part  60 . 
     The control part  60  for controlling the air conditioning has a microcomputer etc., and drives the body  50  of the device according to an input signal input from an operation panel  61  placed on a dashboard, etc. in the automobile cabin. On the operation panel  61  are placed an air conditioning switch  61   a , which turns the air conditioner AC ON or OFF, a mode switch  61   b  which switches the air-blowing mode to DEF, VENT, or FOOT, an intake switch  61   c  which switches intake of the air from inside or outside of the automobile cabin, a temperature control switch  61   d , which controls the set temperature, and a display unit  61   e  for displaying the contents set by these switches. Further, the control part  60  controls the blower fan  52 , the air mix door  53 , the air-blowing mode door  54 , the intake door  56 , etc., to desired operating positions by comparing the conditions set at the operation panel  61  with the present temperature input from various temperature sensors  62 , such as the external atmospheric temperature sensor  62   a , the internal atmospheric temperature sensor  62   b , and the solar sensor  62   c.    
     Further, the control part  60  is configured so as to input the output signal from the cooling fluid temperature sensor  3 . At the time of an abnormally high output from sensor  3 , the microcomputer within the control part  60  causes the blower fan  52  to be rotated at the maximum speed to maximize the heat radiating out from the heater core  51 . At this time, the occurrence of abnormality appears on the display unit  61   e  of the display panel  61 . 
     The cooling controller B for an internal-combustion engine configured as described above makes it possible to cool the cooling fluid W by radiating out heat through the heater core  51 , even if the radiator fan  4  or the thermostat  40  has failed. Furthermore, a driver can deal with the abnormality in an adequate manner based on the display of the occurrence of the abnormality on the display unit  61   e  of the operation display panel  61 , thereby preventing problems such as overheating ahead of time. 
     When an abnormally high temperature of the cooling fluid W is detected by the cooling fluid temperature sensor  3 , fail-safe can be more effectively carried out by the combination of maximum heat radiation measures such as by opening the intake door  56  for introducing external atmospheric air, driving the blower fan  56  at the maximum, stopping the outdoor unit  55   a  of the air conditioner, and allowing the maximum heat to radiate out of the heater core  51 . 
     Thus, in the invention, when a defect occurs in the radiator or the thermostat in an automobile, etc., so that the cooling fluid cannot be cooled by the radiator, the cooling fluid can be cooled through a heater core of the air conditioner and, thus, problems with overheating can be avoided.