JP6459870B2 - Diagnostic equipment - Google Patents

Description

  The present invention relates to a diagnostic device for a temperature regulating valve that regulates the temperature of cooling water supplied to an internal combustion engine of a vehicle.

  The engine of a vehicle becomes high temperature due to a large amount of combustion heat generated in the combustion stroke. For this reason, the vehicle is equipped with a cooling device that maintains the engine at an appropriate temperature. Such a cooling device generally supplies cooling water to the engine through a circulation channel and cools cooling water discharged from the engine (hereinafter also referred to as “exhaust cooling water”) by a radiator. It has become.

  On the other hand, at the time of starting the engine, in order to increase the combustion efficiency, it is required to warm up the engine and raise the temperature to an appropriate temperature as quickly as possible. During warm-up, it is possible to speed up the temperature rise of the engine by returning the discharged cooling water to the engine without being cooled by the radiator. For this reason, a circulation flow path for circulating the exhaust cooling water to the radiator and a bypass flow path for returning the exhaust cooling water to the engine without circulating it to the radiator are provided. The circulation flow path is provided with a temperature adjustment valve for adjusting the temperature of the cooling water supplied to the engine. In order to appropriately warm up and cool the engine, this temperature control valve is required to have high reliability.

  The following Patent Document 1 describes a vehicle that diagnoses a thermostat that is a temperature control valve. Specifically, the control device included in the vehicle measures the temperature of the discharged cooling water during warm-up, and diagnoses whether there is an abnormality in the temperature adjustment valve based on the relationship between the measured temperature and the threshold value. When the measured temperature of the discharged cooling water shows a tendency to decrease, the vehicle prohibits the diagnosis of the temperature adjustment valve because there is a risk of making a false diagnosis.

JP-A-2015-78657

  Since the abnormality of the temperature control valve has a great influence on the cooling of the engine, it is preferable to perform the diagnosis even after the warm-up is completed. In the above prior art, diagnosis of the temperature adjustment valve is prohibited when the measured temperature of the discharged cooling water shows a tendency to decrease. When the engine warm-up is completed, the exhaust cooling water is circulated through the radiator and supplied to the engine by the operation of the temperature adjustment valve, and the temperature of the cooling water varies based on various causes. Therefore, if an attempt is made to diagnose the temperature adjustment valve simply based on fluctuations in the measured temperature of the discharged cooling water, the diagnosis of the temperature adjustment valve is accurately performed when the temperature of the discharged cooling water decreases due to a cause other than an abnormality of the temperature adjustment valve. Can not do.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a diagnostic device that can accurately diagnose a temperature regulating valve even after the completion of warm-up of an internal combustion engine. .

In order to solve the above-described problems, a diagnostic device according to the present invention is a diagnostic device for a temperature regulating valve (35, 35A) that regulates the temperature of cooling water supplied to an internal combustion engine (20) of a vehicle (1, 1A). A water temperature acquisition unit (11) that acquires the temperature of the discharged cooling water that is the cooling water discharged from the internal combustion engine, and a diagnosis that diagnoses the state of the temperature adjustment valve based on the temperature of the discharged cooling water Part (14). The diagnostic unit executes a heat release amount reduction control for reducing the heat release amount of the exhaust cooling water in the radiator (36) of the vehicle, and increases the temperature of the exhaust cooling water based on the execution of the heat release amount reduction control. When the amount exceeds the rising threshold value, the temperature control valve is diagnosed as abnormal, and after the heat radiation amount reduction control is executed, the heat radiation amount increase control for increasing the heat radiation amount of the discharged cooling water in the radiator is executed. At the same time, when the amount of decrease in the discharge cooling water temperature is equal to or greater than the decrease threshold based on the execution of the heat dissipation increase control, the temperature adjustment valve is diagnosed as abnormal and the exhaust cooling based on the execution of the heat dissipation decrease control is performed. When the amount of increase in the temperature of the water is not equal to or higher than the increase threshold value, the heat release amount increase control is executed .
In addition, the diagnosis unit executes a heat release amount reduction control for reducing the heat release amount of the discharged cooling water in the radiator (36) of the vehicle, and an increase in the temperature of the discharge cooling water increases based on the execution of the heat release amount reduction control. If the temperature adjustment valve exceeds the threshold value, it is diagnosed that the temperature adjustment valve is abnormal, and after execution of the heat dissipation amount reduction control, the heat dissipation amount increase control for increasing the heat dissipation amount of the discharged cooling water in the radiator is executed, and the heat dissipation amount Based on the execution of the increase control, when the amount of decrease in the temperature of the discharged cooling water exceeds the decrease threshold, it is diagnosed that the temperature adjustment valve is abnormal, and one of the heat dissipation increase control and the heat dissipation decrease control is executed. As a result, if the amount of increase or decrease in the temperature of the discharged cooling water is greater than or equal to the first threshold, it is diagnosed that the temperature adjustment valve is abnormal, and the amount of increase or decrease in the temperature of the discharged cooling water is less than the first threshold. Small and If so than the second threshold value, performing the other heat radiation amount increase control and the radiation loss control.

  In the diagnosis apparatus configured as described above, a heat release amount reduction control for reducing the heat release amount of the discharged cooling water in the radiator is executed. When the discharged cooling water is supplied to the radiator due to the abnormality of the temperature adjustment valve, the temperature of the discharged cooling water tends to rise when such a heat radiation amount reduction control is executed. In this diagnostic apparatus, when the amount of increase in the temperature of the discharged cooling water is equal to or higher than the increase threshold, the temperature adjustment valve is diagnosed as abnormal. Therefore, according to this diagnostic apparatus, even when the temperature of the exhaust cooling water decreases after completion of warming up of the internal combustion engine, it is possible to accurately diagnose the temperature adjustment valve.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a diagnostic device that can accurately diagnose a temperature regulating valve even after the completion of warm-up of an internal combustion engine. .

It is a schematic diagram which shows the structure of the diagnostic apparatus which concerns on 1st Embodiment, and the vehicle by which the said diagnostic apparatus is mounted. It is a functional block diagram which shows ECU of FIG. It is explanatory drawing which shows the driving | operation area | region of the engine of FIG. It is explanatory drawing which shows the decision logic of permission of a diagnosis by the ECU of FIG. 1, or holding | maintenance. It is a time chart which shows the change of permission or suspension of diagnosis by ECU of FIG. It is a flowchart which shows the process which ECU of FIG. 1 performs. It is explanatory drawing which shows the heat radiation amount reduction | decrease control and the heat radiation amount increase control which ECU of FIG. 1 performs. It is a schematic diagram which shows the structure of the diagnostic apparatus which concerns on 2nd Embodiment, and the vehicle by which the said diagnostic apparatus is mounted. It is explanatory drawing which shows operation | movement of the electric valve of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  First, the ECU 10 according to the first embodiment and the vehicle 1 equipped with the ECU 10 will be described with reference to FIG. The vehicle 1 is equipped with an engine 20 that is an internal combustion engine as a power source.

  The engine 20 is, for example, a reciprocating engine that uses gasoline as fuel. The engine 20 includes a cylinder head 21 and a cylinder block 22. The engine 20 has a plurality of cylinders (not shown). Each cylinder generates torque by repeatedly performing each stroke of an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke. The torque is output via a crankshaft (not shown) of the engine 20 and is used for traveling of the vehicle 1.

  Each cylinder of the engine 20 sucks combustion air from the outside through the air introduction path 23 in the intake process. Further, each cylinder of the engine 20 discharges the gas generated inside during the combustion stroke to the exhaust gas flow path 24 during the exhaust stroke. The air introduction path 23 and the exhaust gas flow path 24 are both air flow paths formed inside the piping. The exhaust gas channel 24 has a first exhaust channel 241 and a second exhaust channel 242. The second discharge channel 242 is formed to branch from the first discharge channel 241 and to join the first discharge channel 241 on the downstream side thereof. Thus, the second discharge flow path 242 is a flow path that bypasses the turbine 51 provided in the first discharge flow path 241.

  In addition, the vehicle 1 includes a cooling device 30, an air conditioner 40, and a supercharger 50.

  The cooling device 30 is a device that cools the engine 20 that generates a large amount of combustion heat in the combustion stroke and maintains the engine 20 at an appropriate temperature. The cooling device 30 includes a water pump 31, an engine cooling passage 32, a circulation passage 33, a bypass passage 34, a radiator 36, a radiator fan 37, and a radiator shutter 38.

  The water pump 31 is a fluid machine that pumps cooling water. The cooling water contains LLC that is an antifreeze. The water pump 31 is rotationally driven by receiving a part of the output of the engine 20 via the crankshaft. By the rotational drive of the water pump 31, the cooling water supplied from the upstream side of the water pump 31 is pressurized and supplied downstream.

  The engine cooling channel 32 is a cooling water channel formed inside the engine 20. For example, an engine cooling channel 32 is formed inside the cylinder block 22 so as to wrap around each cylinder.

  The circulation channel 33 is a cooling water channel formed inside the pipe. One end of the pipe is connected to the downstream end of the engine cooling flow path 32, and the other end is connected to the water pump 31. Thereby, the circulation flow path 33 is a flow path for circulating the cooling water to the engine 20 together with the engine cooling flow path 32. The circulation flow path 33 has a first circulation flow path 331 extending from the downstream end of the engine cooling flow path 32 to a radiator 36 described later, and a second circulation flow path 332 extending from the radiator 36 to the water pump 31. .

  The bypass channel 34 is a cooling water channel formed inside the pipe. One end of the pipe is connected in the middle of the pipe forming the first circulation channel 331, and the other end is connected in the middle of the pipe forming the second circulation channel 332. As a result, the bypass flow path 34 is branched from the first circulation flow path 331 and is a flow path that bypasses the radiator 36 and merges in the middle of the second circulation flow path 332.

  The radiator 36 is a heat exchanger provided in the circulation flow path 33. Each radiator 36 has a tube and a corrugated fin (not shown). The tube is a metallic tubular member that allows cooling water to flow inside. The corrugated fin is formed by bending a metal plate. The radiator 36 is formed by alternately laminating a plurality of corrugated fins and a plurality of corrugated fins.

  The radiator fan 37 is a blower provided adjacent to the radiator 36. When the control signal transmitted from the ECU 10 is received and the radiator fan 37 is rotationally driven, air is taken in through a grill (not shown) of the vehicle 1 as indicated by an arrow AF. This air passes through the radiator 36 by flowing between adjacent tubes of the radiator 36, and exchanges heat with the cooling water flowing inside the tube. Thereby, the heat of the cooling water flowing through the radiator 36 is dissipated, and the temperature decreases.

  The radiator shutter 38 is provided upstream of the radiator 36 in the air flow direction indicated by the arrow AF. The radiator shutter 38 is configured to receive a control signal transmitted from the ECU 10 and change the opening based on the control signal. By changing the opening degree of the radiator shutter 38, the flow rate of the air passing through the radiator 36 and the area where heat exchange between the cooling water and the air in the radiator 36 can be changed.

  In addition, a thermostat 35 is arranged on the downstream side of a portion where the pipe forming the bypass flow path 34 branches from the pipe forming the circulation flow path 33 and on the radiator 36 side. The thermostat 35 has a valve body (not shown) inside. The valve body inside the thermostat 35 is configured to move in response to the temperature of the cooling water in the vicinity thereof. The thermostat 35 is configured to be switched between a closed state and an open state by the movement of the valve body. And the thermostat 35 is based on the temperature of the cooling water, and the flow rate of the cooling water supplied to the engine 20 via the radiator 36 and the flow rate of the cooling water supplied to the engine 20 via the bypass flow path 34. Adjust the ratio.

  The air conditioner 40 is a device that adjusts the temperature in the passenger compartment of the vehicle 1. The air conditioner 40 has a refrigerant flow path 47 for circulating the refrigerant. The air conditioner 40 includes a heater core 41, an evaporator 42, a blower 43, a compressor 44, a condenser 45, and an expansion valve 46.

  The heater core 41 is a heat exchanger provided in the middle of the bypass flow path 34. Each of the heater cores 41 has a tube and a corrugated fin (not shown). The tube is a metallic tubular member that allows cooling water to flow inside. The corrugated fin is formed by bending a metal plate. The heater core 41 is formed by alternately laminating a plurality of corrugated fins and a plurality of corrugated fins.

  The evaporator 42 is a heat exchanger provided in the refrigerant flow path 47. The evaporator 42 is formed with a flow path (not shown) through which a refrigerant flows. The evaporator 42 takes heat away from the air flowing on the surface by the liquid-phase refrigerant flowing through the internal flow path. The liquid refrigerant is evaporated by the heat taken away, whereby the air flowing on the surface of the evaporator 42 is cooled.

  The blower 43 is a blower provided in the vicinity of the heater core 41 and the evaporator 42. When the blower 43 is rotationally driven by receiving a control signal transmitted from the ECU 10, air is taken in from the vehicle interior or the outside of the vehicle and supplied to the heater core 41 and the evaporator 42. The air exchanges heat when passing through the heater core 41 and the evaporator 42, and its temperature is adjusted. The temperature-adjusted air is supplied into the passenger compartment.

  The compressor 44 is a fluid machine provided in the refrigerant flow path 47. When the control signal transmitted from the ECU 10 is received and the compressor 44 is driven to rotate, the refrigerant discharged from the evaporator 42 is compressed by the compressor 44. The compressed refrigerant is further supplied to the downstream side of the refrigerant flow path 47.

  The condenser 45 is a heat exchanger provided in the refrigerant flow path 47. Further, the condenser 45 is provided upstream of the radiator 36 in the air flow direction indicated by the arrow AF. The capacitor 45 has a flow path (not shown) through which a refrigerant flows. The refrigerant compressed by the compressor 44 and supplied downstream is supplied to the flow path inside the condenser 45. The refrigerant flowing through the flow path dissipates heat by exchanging heat with the air passing through the condenser 45 as indicated by an arrow AF.

  The expansion valve 46 is a valve mechanism provided in the refrigerant flow path 47. The expansion valve 46 decompresses the refrigerant that passes through the condenser 45 and is supplied to the evaporator 42.

  The supercharger 50 is a device that compresses the air in the air introduction path 23 and supplies the compressed air to the engine 20. The supercharger 50 includes a turbine 51, an air compressor 52, an intercooler 54, and a waste gate valve 55.

  The turbine 51 is a prime mover that converts the energy of the fluid into mechanical power. The turbine 51 is provided in the first exhaust passage 241 of the exhaust gas passage 24. When the exhaust gas discharged from each cylinder of the engine 20 flows through the first exhaust flow path 241 and passes through the turbine 51, the turbine 51 rotates using the energy of the exhaust gas.

  The air compressor 52 is a fluid machine that compresses fluid by rotating. The air compressor 52 is provided in the air introduction path 23. The air compressor 52 is connected to the turbine 51 by a shaft 53. When the turbine 51 rotates using the energy of the exhaust gas flowing through the first exhaust passage 241, the rotational torque is transmitted to the air compressor 52 by the shaft 53. Thereby, the air compressor 52 rotates, compresses the air in the air introduction path 23, and supplies it downstream.

  The intercooler 54 is a heat exchanger provided in a portion of the air introduction path 23 downstream of the air compressor 52. The intercooler 54 has a flow path (not shown) through which air flows. The air heated to a high temperature by being compressed by the air compressor 52 is supplied to a flow path inside the intercooler 54. The air flowing through the flow path dissipates heat by exchanging heat with the air flowing outside the intercooler 54, and the temperature decreases.

  The waste gate valve 55 is a valve mechanism that opens and closes the flow path. The waste gate valve 55 is provided in the second exhaust passage 242 of the exhaust gas passage 24. The waste gate valve 55 is configured to receive a control signal transmitted from the ECU 10 and change the opening based on the control signal. By changing the opening degree of the waste gate valve 55, the flow rate of the exhaust gas flowing through the first exhaust channel 241 of the exhaust gas channel 24 to the turbine 51 side and the second exhaust gas is shunted from the first exhaust channel 241. The ratio of the flow rate of the exhaust gas flowing to the flow path 242 side can be adjusted. Thereby, the rotation speed of the turbine 51 can be controlled to obtain a stable supercharging pressure, and the turbine 51 can be protected from damage.

  The operation of the cooling device 30, the air conditioner 40, and the supercharger 50 configured as described above will be described with reference to FIG.

<About the operation of the cooling device 30>
When the engine 20 is started by receiving the supply of fuel, the temperature of the engine 20 gradually increases due to a large amount of combustion heat generated in the combustion stroke. The water pump 31 receives the output of the engine 20 via the crankshaft and rotates. Thereby, the cooling water in the second circulation channel 332 is pressurized and supplied to the engine cooling channel 32 of the engine 20.

  The cooling water exchanges heat with the cylinder head 21 and the cylinder block 22 while flowing through the engine cooling flow path 32. Thereby, while the cylinder head 21 and the cylinder block 22 are deprived of heat and cooled, the cooling water receives heat and the temperature rises.

  In a state immediately after the engine 20 is started, the temperature of the engine 20 is relatively low. Therefore, cooling water that is discharged from the engine cooling flow path 32 and flows through the first circulation flow path 331 (hereinafter referred to as “discharged cooling water”). Temperature) is also relatively low. In this case, the valve body of the thermostat 35 is disposed at a position where the first circulation channel 331 is closed.

  Thus, the discharged cooling water flows through the bypass flow path 34 without being supplied to the radiator 36 and is supplied to the second circulation flow path 332. That is, when the temperature of the engine 20 is relatively low, the cooling water circulates while bypassing the radiator 36. In this case, since the discharged cooling water is not cooled by the radiator 36, the engine 20 is not excessively cooled by the cooling water. Therefore, the warm-up at the start of the engine 20 is not hindered by the cooling water.

  On the other hand, when the temperature of the engine 20 is equal to or higher than the appropriate temperature, the temperature of the discharged cooling water is also relatively high. In this case, the valve body of the thermostat 35 is disposed at a position where the first circulation channel 331 is opened.

  Thereby, a part of the discharged cooling water is supplied to the radiator 36, and the remaining part flows through the bypass flow path 34 and is supplied to the second circulation flow path 332. In other words, in a state where the engine 20 is at an appropriate temperature or more, a part of the discharged cooling water supplied to the radiator 36 is cooled, and the remaining discharged cooling water flows around the radiator 36. These cooling waters merge in the second circulation channel 332, are pressurized by the water pump 31, and are supplied to the engine cooling channel 32 again.

<Operation of air conditioner 40>
When the air conditioner 40 heats the vehicle interior of the vehicle 1, the air taken in from the vehicle interior or the outside of the vehicle is first passed through the evaporator 42 to be cooled. During this cooling, the water vapor contained in the air is removed as condensed water, whereby the air is dehumidified. The air conditioner 40 then passes the dehumidified air through the heater core 41 and exchanges heat with the high-temperature exhaust cooling water flowing inside the heater core 41. The air whose temperature has been increased by this heat exchange is guided into the vehicle interior of the vehicle 1 by a duct (not shown), thereby heating the vehicle interior.

  On the other hand, when the air conditioner 40 cools the passenger compartment of the vehicle 1, the air cooled by passing through the evaporator 42 is guided to the passenger compartment without passing through the heater core 41 or hardly passing through it. Thereby, the air cooled in the evaporator 42 is supplied into the vehicle interior, and the vehicle interior is cooled.

<About operation of supercharger 50>
As described above, when the exhaust gas discharged from the engine 20 passes and the turbine 51 rotates, the air compressor 52 rotates accordingly. The air in the air introduction path 23 is compressed by the rotating air compressor 52 to become high temperature and high pressure, and is supplied to an intercooler 54 provided on the downstream side of the air introduction path 23.

  The air supplied to the intercooler 54 flows through a flow path formed inside the intercooler 54. The air flowing through the flow path dissipates heat by exchanging heat with the air flowing outside the intercooler 54, and the temperature decreases. By supplying the high-pressure air whose temperature has decreased in this way to the engine 20 through the air introduction path 23 and using it for fuel combustion, the combustion efficiency can be increased and the output of the engine 20 can be improved.

  Next, an ECU (Electronic Control Unit) 10 will be described with reference to FIG. The ECU 10 is partially or entirely configured by an analog circuit or a digital processor. In any case, in order to fulfill the function of outputting a control signal based on the received signal, the ECU 10 includes a functional control block.

  FIG. 2 shows the ECU 10 as a functional control block diagram. The software module incorporated in the analog circuit or digital processor that constitutes the ECU 10 does not necessarily have to be divided like the control block shown in FIG. That is, an actual analog circuit or module may be configured to function as a plurality of control blocks shown in FIG. 2, or may be further subdivided. A person skilled in the art can appropriately change the actual configuration inside the ECU 10 as long as the processing described later can be executed.

  The ECU 10 is electrically connected to each of the water temperature sensor 61, the air-fuel ratio sensor 62, the crank angle sensor 63, and the outside air temperature sensor 64. The water temperature sensor 61 is a sensor that is disposed in the first circulation flow path 331 (see FIG. 1) and generates and transmits a signal corresponding to the temperature Tw of the discharged cooling water. The air-fuel ratio sensor 62 is a sensor that is provided in the exhaust gas passage 24 (see FIG. 1) and generates and transmits a signal corresponding to the oxygen concentration of the exhaust gas. The crank angle sensor 63 is a sensor that is attached to the engine 20 (see FIG. 1) and generates and transmits a signal corresponding to the angle of the crankshaft. The outside air temperature sensor 64 is a sensor that is disposed in a part of the vehicle 1 that contacts outside air (see FIG. 1), and generates and transmits a signal corresponding to the outside air temperature.

  The ECU 10 is also electrically connected to in-vehicle devices such as the engine 20, the radiator fan 37, the radiator shutter 38, the blower 43, the compressor 44, the waste gate valve 55, and the notification device 70. The notification device 70 is a device for performing various notifications to passengers of the vehicle 1. The notification device 70 is configured by a known device such as a display panel or a buzzer. The ECU 10 controls the operation of each in-vehicle device by transmitting a control signal.

  In the present application, “electrically connected” is not limited to a form in which signals are connected to each other via a signal line, but may include a form in which wireless communication is possible.

  The ECU 10 includes a calculation unit 11, a storage unit 12, a counter unit 13, and a diagnosis unit 14.

  The calculation part 11 is a part which performs various calculations required for control of each vehicle-mounted apparatus. Specifically, the calculation unit 11 performs calculation for causing the engine 20 to generate torque in response to depression of an unillustrated accelerator by the driver. Moreover, the calculating part 11 performs a predetermined calculation based on the signal received from the water temperature sensor 61, and acquires the temperature of discharge cooling water. The calculation unit 11 performs a predetermined calculation based on a signal received from the air-fuel ratio sensor 62, and calculates an air-fuel ratio in the cylinder of the engine 20, a flow rate of air supplied into the cylinder, and the like. In addition, the calculation unit 11 performs a predetermined calculation based on a signal received from the crank angle sensor 63 and acquires the rotational speed of the engine 20. In addition, the calculation unit 11 performs a predetermined calculation based on a signal received from the outside air temperature sensor 64 and acquires the outside air temperature. Further, as will be described later, the calculation unit 11 calculates the amount of heat (hereinafter also referred to as “heat receiving amount”) transmitted from the engine 20 to the cooling water per unit time based on the rotational speed of the engine 20 and the like. As will be described later, the calculation unit 11 calculates the amount of heat released from the cooling water per unit time (hereinafter also referred to as “heat dissipation amount”) based on the outside air temperature and the like.

  The storage unit 12 is a part that stores various information. The storage unit 12 is configured by a nonvolatile memory, for example. Information such as a map is stored in the storage unit 12 in advance. The information is read by the calculation unit 11 and used for calculation. The storage unit 12 can store the calculation result of the calculation unit 11.

  The counter unit 13 is a part that performs various counts. For example, the counter unit 13 counts the length of time or the like that the engine 20 has operated in a specific operation region among the operation regions of the engine 20 divided into a plurality.

  The diagnosis unit 14 is a part that diagnoses the thermostat 35. Specifically, the diagnosis unit 14 diagnoses whether there is an abnormality in which the valve body of the thermostat 35 cannot move normally and the aforementioned closed state and open state cannot be switched.

  FIG. 3 shows a heat reception amount Qrc map in which the rotational speed of the engine 20 is plotted on the horizontal axis and the amount of air taken in by the engine 20 is plotted on the vertical axis. The heat reception amount Qrc map is stored in the storage unit 12 of the ECU 10. The upper limit of the amount of air that the engine 20 takes in at each rotation speed is a value indicated by a solid line WOT (Wide Open throttle).

  When engine 20 operates along solid lines Qrc1, Qrc2, Qrc0, and Qrc3, the received heat quantity Qrc of the cooling water is Qrc1, Qrc2, Qrc0, and Qrc3, respectively. The received heat amounts Qrc1, Qrc2, Qrc0, and Qrc3 are values that decrease in this order. That is, in the map shown in FIG. 3, as the region in which the engine 20 is operating is at the upper right, the heat receiving amount Qrc of the cooling water has a larger value. Further, the map shown in FIG. 3 can also be created by plotting the torque generated by the engine 20 on the vertical axis instead of the amount of air taken in by the engine 20.

  Here, when the engine 20 is operating in the A region (that is, the region to which the heat receiving amounts Qrc1 and Qrc2 belong) where the heat receiving amount Qrc of the cooling water has a value larger than Qrc0 and smaller than the solid line WOT, The heat receiving amount Qrc of the cooling water is larger than the heat dissipation amount Qrd. In this case, the temperature of the discharged cooling water tends to increase based on the heat balance.

  On the other hand, when the engine 20 is operating in the B region (that is, the region to which the heat receiving amount Qrc3 belongs) in which the heat receiving amount Qrc of the cooling water is smaller than Qrc0 and smaller than the solid line WOT, The amount of heat received Qrc of water is smaller than the amount of heat released Qrd. In this case, the temperature of the discharged cooling water tends to decrease based on the heat balance. That is, the amount of heat received Qrc0 is a threshold at which the temperature of the discharged cooling water starts to rise or fall from that point.

  When the engine 20 is operating in the B region and the temperature of the discharged cooling water is decreasing, it is difficult to determine whether it is due to an abnormality in the thermostat 35 or due to other causes. Therefore, if the thermostat 35 is diagnosed in such a state, there is an increased concern that the diagnosis result will be incorrect. When the frequency with which the engine 20 is operating in the B region is high, it is preferable to hold the diagnosis of the thermostat 35.

  Next, referring to FIG. 4 and FIG. 5, the diagnosis permission and suspension determination of the thermostat 35 will be described.

  As shown in FIG. 4, the calculation unit 11 (see FIG. 2) of the ECU 10 compares the rotation speed of the engine 20 and the air amount when the engine 20 takes in the heat reception amount Qrc map stored in the storage unit 12. . As a result, the heat receiving amount Qrc of the cooling water in the operating state of the engine 20 is obtained.

  Moreover, the calculation part 11 of ECU10 collates the rotation speed of the engine 20 with the heat passage rate h map. The heat passage rate h is a constant used when calculating the heat transferred from the cooling water to the outside air. The heat passage rate h is experimentally identified in advance in consideration of the material characteristics and shape of the piping that forms the circulation flow path 33 and the bypass flow path 34, and has a correlation with the flow rate of the cooling water. In the present embodiment, the water pump 31 that pumps the cooling water is driven to rotate in response to the output of the engine 20, so the flow rate of the cooling water has a correlation with the rotational speed of the engine 20. Therefore, the heat transfer rate h map here corresponds to the rotation speed of the engine 20 and the heat transfer rate h at the rotation speed. By comparing the rotational speed of the engine 20 with the heat transfer rate h map, the heat transfer rate h is obtained.

  Further, the calculation unit 11 calculates a temperature difference ΔT that is a difference between the outside air temperature and the cooling water temperature. And the calculating part 11 obtains the thermal radiation amount Qrd of cooling water by multiplying this temperature difference (DELTA) T and the heat passage rate h.

  The ECU 10 compares the heat receiving amount Qrc of the cooling water obtained as described above and the heat dissipation amount Qrd. When the heat radiation amount Qrd is larger than the heat reception amount Qrc, the engine 20 is operating in the region B shown in FIG. 3, and the temperature of the exhaust cooling water tends to decrease.

  Then, the ECU 10 calculates the time Trd during which the heat dissipation amount Qrd is greater than the heat receiving amount Qrc during the predetermined period during which the engine 20 is operating, and calculates the ratio of the time Trd to the time length of the predetermined period. To do. The ECU 10 determines whether this ratio is 50% or more. When this ratio is 50% or more, the engine 20 is frequently operated in the B region, and there is a great concern that the diagnosis result of the thermostat 35 is erroneous. Therefore, the diagnosis unit 14 of the ECU 10 diagnoses the thermostat 35. Hold on. On the other hand, when the ratio of the time Trd to the time length of the predetermined period is less than 50%, there is little concern that the diagnosis result of the thermostat 35 is incorrect, and thus the diagnosis unit 14 of the ECU 10 does not hold the diagnosis (that is, Allow diagnosis).

  In FIG. 5, the change between permitting and holding the diagnosis of the thermostat 35 is illustrated along with the change in time. The counter unit 13 (see FIG. 2) of the ECU 10 counts the operation time of the engine 20 from the time t0. Between time t0 and time t1, since the engine 20 does not operate in the region B shown in FIG. 3, the time with respect to the length of time that the engine 20 is operating (a line indicated as “whole” in FIG. 5) The ratio of Trd (the line indicated as “B region” in FIG. 5) is less than 50%. In this case, the diagnosis unit 14 of the ECU 10 does not hold the diagnosis (that is, permits the diagnosis).

  At time t1, for example, when new combustion heat generated in the engine 20 decreases, the amount of cooling water received decreases, and the frequency at which the engine 20 operates in the B region gradually increases. The counter unit 13 of the ECU 10 starts counting the time Trd during which the engine 20 is operating in the B region.

  When the ratio of the time Trd to the total time length during which the engine 20 is operating reaches 50% at time t2, the diagnosis unit 14 of the ECU 10 holds the diagnosis. As a result, the diagnosis of the thermostat 35 in a situation where there is a high risk of misdiagnosis is suspended. That is, the operating condition of the engine 20 after the time t2 is such that the temperature of the discharged cooling water is lower than the operating condition of the engine 20 until the time t2.

  Subsequently, a flow of processing executed by the ECU 10 will be described with reference to FIGS. 6 and 7. FIG. 6 is a flowchart showing a process executed by the ECU 10 after the warm-up of the engine 20 is completed. In the following, for the sake of simplicity, the processing executed by the arithmetic unit 11 and the like of the ECU 10 will be described as being executed by the ECU 10 as a whole.

  First, in step S1 shown in FIG. 6, the ECU 10 determines whether or not the temperature Tw of the discharged cooling water is lower than a predetermined threshold value Twc. When it is determined that the temperature Tw of the discharged cooling water is not lower than the threshold value Twc, the ECU 10 proceeds to the process of step S12, and the thermostat 35 diagnoses that it is normal. On the other hand, when it is determined that the temperature Tw of the discharged cooling water is lower than the threshold value Twc as at time t3 shown in FIG. 7, the ECU 10 proceeds to the process of step S2 shown in FIG.

  Next, ECU10 determines whether the ratio which the engine 20 is drive | operating in the B area | region shown by FIG. 3 is 50% or more by step S2. When it is determined that the ratio is 50% or more, the ECU 10 proceeds to the process of step S3.

  Next, the ECU 10 suspends the diagnosis of the thermostat 35 in step S3. That is, in step S2 described above, since it is determined that the engine 20 is frequently operating in the B region and there is a great concern that the result of the diagnosis is erroneous, the ECU 10 withholds the diagnosis.

  Next, the ECU 10 executes a heat radiation amount reduction control in step S4. In this heat radiation amount reduction control, the in-vehicle device is controlled so as to reduce the heat radiation amount of the discharged cooling water in the radiator 36. Hereinafter, this heat radiation amount reduction control will be described.

  As indicated by a broken line in FIG. 7, the ECU 10 changes the opening degree of the radiator shutter 38 from Dr2 to Dr1 at time t4. The opening degree Dr1 is a value smaller than the opening degree Dr2. As described above, when the opening degree of the radiator shutter 38 is reduced in the heat radiation amount reduction control, the flow rate of the air passing through the radiator 36 and the area where heat is exchanged between the discharged cooling water and the air in the radiator 36 are reduced.

  By reducing the flow rate of air passing through the radiator 36, the heat exchange between the exhaust cooling water and the air in the radiator 36 is slowed down. Thereby, the heat radiation amount of the discharged cooling water in the radiator 36 is reduced.

  When the ECU 10 executes such heat radiation amount reduction control, the temperature Tw of the discharged cooling water flowing through the circulation passage 33 tends to increase. However, when the thermostat 35 is normal, the internal valve body moves in response to an increase in the temperature Tw of the discharged cooling water, and supplies more discharged cooling water to the radiator 36. As a result, as shown by “normal” in FIG. 7, the temperature Tw of the discharged cooling water is kept substantially constant after time t4 when the execution of the heat radiation amount reduction control is started. Therefore, the temperature change | ΔTw | of the discharged cooling water from time t4 is substantially zero. The temperature change | ΔTw | of the discharged cooling water is an absolute value.

  On the other hand, when the thermostat 35 is abnormal, even if the heat radiation amount reduction control is executed, the internal valve body cannot move appropriately. As a result, as shown by “abnormality 1” in FIG. 7, the temperature Tw of the discharged cooling water shows an increasing tendency after time t4 when the execution of the heat radiation amount reduction control is started. Therefore, the temperature change | ΔTw | of the discharged cooling water from time t4 increases.

  The description will be continued with reference to FIG. 6 again. In step S5, the ECU 10 determines whether or not the temperature change | ΔTw | of the discharged cooling water is smaller than a predetermined threshold C1. The ECU 10 executes the process of step S5 at a time t5 when a predetermined time has elapsed from the time t4 (see FIG. 7) at which execution of the heat radiation amount reduction control is started. When the temperature change | ΔTw | of the discharged cooling water is smaller than the threshold value C1, it can be estimated that the valve body inside the thermostat 35 is in a state where it can be appropriately moved along with the execution of the heat radiation amount reduction control. Therefore, in this case, the ECU 10 proceeds to the process of step S12 and diagnoses that the thermostat 35 is normal.

  On the other hand, when it is determined that the temperature change | ΔTw | of the discharged cooling water at time t4 is not smaller than the threshold C1, as indicated by “abnormality 1” in FIG. 7, the ECU 10 proceeds to the process of step S6.

  Next, in step S6, the ECU 10 determines whether or not the temperature change | ΔTw | of the discharged cooling water is equal to or greater than a predetermined threshold C2. The threshold value C2 is a value larger than the threshold value C1 described above. As indicated by “abnormality 1” in FIG. 7, when the temperature change | ΔTw | of the discharged cooling water at time t4 is C3 that is equal to or greater than the threshold value C2, the valve body inside the thermostat 35 reduces the heat dissipation amount. It can be estimated that the vehicle cannot move properly as the control is executed. Therefore, in this case, the ECU 10 proceeds to the process of step S10, and the thermostat 35 diagnoses that it is abnormal. Further, the ECU 10 can operate the notification device 70 in step S11 to prompt the user of the vehicle 1 to perform inspection or the like.

  On the other hand, when it is determined in step S6 that the temperature change | ΔTw | of the discharged cooling water is not equal to or greater than the threshold value C2 (that is, when C1 <| ΔTw | <C2), the thermostat 35 is either normal or abnormal. It is difficult to clearly diagnose whether this is a condition. In this case, the ECU 10 proceeds to the process of step S7.

  Next, ECU10 performs heat dissipation increase control in step S4. In this heat dissipation amount increase control, the in-vehicle device is controlled so as to increase the heat dissipation amount of the discharged cooling water in the radiator 36. Hereinafter, this heat dissipation increase control will be described.

  The ECU 10 changes the opening degree of the radiator shutter 38 from Dr2 so far to Dr3 at time t4, as indicated by a one-dot chain line in FIG. The opening degree Dr3 is a value larger than the opening degree Dr2. As described above, when the opening degree of the radiator shutter 38 is increased in the heat dissipation amount increase control, the flow rate of the air passing through the radiator 36 and the area in which heat is exchanged between the discharged cooling water and the air in the radiator 36 are increased.

  By increasing the flow rate of the air passing through the radiator 36, heat exchange between the exhaust cooling water and the air in the radiator 36 is promoted. Thereby, the heat radiation amount of the discharged cooling water in the radiator 36 increases.

  When the ECU 10 executes such heat release amount increase control, the temperature Tw of the discharged cooling water flowing through the circulation flow path 33 tends to decrease. However, when the thermostat 35 is normal, the internal valve body moves in response to a decrease in the temperature Tw of the discharged cooling water, and the flow rate of the cooling water supplied to the radiator 36 is reduced. As a result, as shown by “normal” in FIG. 7, the temperature Tw of the discharged cooling water is kept substantially constant after time t4 when the execution of the heat release amount increase control is started. Therefore, the temperature change | ΔTw | of the discharged cooling water from time t4 is substantially zero.

  On the other hand, when the thermostat 35 is abnormal, even if the heat release amount increase control is executed, the internal valve body cannot move appropriately. As a result, as shown by “abnormality 2” in FIG. 7, the temperature Tw of the discharged cooling water tends to decrease after time t4 when the execution of the heat release amount increase control is started. Therefore, the temperature change | ΔTw | of the discharged cooling water from time t4 increases.

  The description will be continued with reference to FIG. 6 again. In step S8, the ECU 10 determines whether or not the temperature change | ΔTw | of the discharged cooling water is smaller than a predetermined threshold C1. The ECU 10 executes the process of step S5 at a time t5 when a predetermined time has elapsed from the time t4 (see FIG. 7) at which execution of the heat dissipation amount increase control is started. When the temperature change | ΔTw | of the discharged cooling water is smaller than the threshold value C1, it can be estimated that the valve body inside the thermostat 35 is in a state where it can be appropriately moved along with the execution of the heat radiation amount reduction control. Therefore, in this case, the ECU 10 proceeds to the process of step S12 and diagnoses that the thermostat 35 is normal.

  On the other hand, as indicated by “abnormality 2” in FIG. 7, when it is determined that the temperature change | ΔTw | of the discharged cooling water at time t4 is not smaller than the threshold value C1, the ECU 10 proceeds to the process of step S9.

  Next, in step S9, the ECU 10 determines whether or not the temperature change | ΔTw | of the discharged cooling water is equal to or greater than a predetermined threshold C2. As indicated by “abnormality 2” in FIG. 7, when the temperature change | ΔTw | of the discharged cooling water at time t4 is C3 that is equal to or greater than the threshold C2, the valve body inside the thermostat 35 increases the heat dissipation amount. It can be estimated that the vehicle cannot move properly as the control is executed. Therefore, in this case, the ECU 10 proceeds to the process of step S10, and the thermostat 35 diagnoses that it is abnormal. Further, the ECU 10 can operate the notification device 70 in step S11 to prompt the user of the vehicle 1 to perform inspection or the like.

  On the other hand, when it is determined in step S9 that the temperature change | ΔTw | of the cooling water is not equal to or greater than the threshold value C2 (that is, when C1 <| ΔTw | <C2), the thermostat 35 is either normal or abnormal. It is difficult to clearly diagnose the condition. In this case, the ECU 10 returns to the process of step S3 and executes the process described above.

  As described above, the ECU 10 according to the first embodiment is a diagnostic device for the thermostat 35 that adjusts the temperature of the cooling water supplied to the engine 20 of the vehicle 1. The ECU 10 includes a calculation unit 11 that acquires a temperature Tw of discharged cooling water that is cooling water discharged from the engine 20, and a diagnosis unit 14 that diagnoses the state of the thermostat 35 based on the temperature Tw of the discharged cooling water. . The diagnosis unit 14 performs a heat release amount reduction control for reducing the heat release amount of the discharged cooling water in the radiator 36 of the vehicle 1, and the amount of increase in the temperature of the discharged cooling water is an increase threshold based on the execution of the heat release amount reduction control. When it becomes more than a certain C2, it is diagnosed that the thermostat 35 is abnormal.

  In the ECU 10 configured as described above, a heat release amount reduction control for reducing the heat release amount of the discharged cooling water in the radiator 36 is executed. When the discharge cooling water is supplied to the radiator 36 due to an abnormality in the thermostat 35, the temperature Tw of the discharge cooling water tends to rise when such a heat radiation amount reduction control is executed. The ECU 10 diagnoses that the thermostat 35 is abnormal when the amount of increase in the temperature Tw of the discharged cooling water (corresponding to the aforementioned temperature change | ΔTw |) of the cooling water is equal to or greater than the threshold C2. Therefore, according to the ECU 10, it is possible to accurately diagnose the thermostat 35 even when the temperature Tw of the discharged cooling water decreases after the warm-up of the engine 20 is completed.

  Further, in the ECU 10, the diagnosis unit 14 executes the heat release amount increase control for increasing the heat release amount of the discharge cooling water in the radiator 36 after the heat release amount decrease control is executed, and the exhaust cooling based on the execution of the heat release amount increase control. When the decrease amount of the water temperature Tw becomes equal to or higher than the threshold value C2 that is the decrease threshold value, the thermostat 35 is diagnosed as abnormal.

  In the ECU 10 configured as described above, the heat release amount increase control for increasing the heat release amount of the discharged cooling water in the radiator 36 is executed. When the discharge cooling water is supplied to the radiator 36 due to an abnormality in the thermostat 35, when such heat release amount increase control is executed, the temperature Tw of the discharge cooling water tends to decrease. The ECU 10 diagnoses that the thermostat 35 is abnormal when the amount of decrease in the temperature Tw of the discharged cooling water (corresponding to the above-described temperature change | ΔTw |) of the cooling water is equal to or greater than the threshold C2. Therefore, according to the ECU 10, it is possible to accurately diagnose the thermostat 35 even when the temperature Tw of the cooling water decreases after the warm-up of the engine 20 is completed.

  In the ECU 10 according to the first embodiment, both the rising threshold value and the decreasing threshold value are set to the threshold value C2. However, the increase threshold value and the decrease threshold value are not necessarily the same value, and may be set to different values depending on the characteristics of the engine 20 and the cooling water.

  Further, in the ECU 10, the diagnosis unit 14 executes the heat release amount increase control when the increase amount of the discharged cooling water temperature Tw based on the execution of the heat release amount decrease control is not equal to or higher than C2, which is the increase threshold value.

  The ECU 10 configured as described above executes the heat dissipation amount increase control when it is difficult to clearly diagnose whether the thermostat 35 is normal or abnormal even if the heat dissipation amount decrease control is executed. be able to. Thereby, when the diagnosis of the thermostat 35 is possible only by the result of executing the heat dissipation amount reduction control, the diagnosis is completed quickly, while when the clear diagnosis is difficult only by the result of executing the heat dissipation amount reduction control. In addition, the accuracy of diagnosis can be improved by executing the heat release amount increase control.

  In addition, even if the temperature Tw of the discharged cooling water is lower than the threshold value Twc and an abnormality of the thermostat 35 is suspected, if the heat dissipation amount increase control is executed prior to the heat dissipation amount decrease control, the discharged cooling water is There is a possibility of further lowering the temperature Tw. In this case, the engine 20 or the like may be greatly affected by the decrease in the temperature Tw of the discharged cooling water. On the other hand, since the ECU 10 executes the heat dissipation amount increase control when the increase amount of the temperature Tw of the discharged cooling water based on the execution of the heat dissipation amount decrease control is not equal to or higher than the increase threshold C2, the ECU 10 suppresses such an adverse effect. can do.

  Further, in the ECU 10, the diagnosis unit 14 executes one of the heat release amount increase control and the heat release amount decrease control, and as a result, | ΔTw |, which is the amount of increase or decrease in the temperature of the discharged cooling water, is equal to or greater than C2 that is the first threshold value. If it is, it is diagnosed that the temperature control valve is abnormal. In addition, the diagnosis unit 14 determines that the amount of increase or decrease in the temperature of the discharged cooling water is smaller than the threshold value C2 and larger than C1 that is the second threshold value. Perform the other side of the control.

  In the ECU 10 configured as described above, | ΔTw |, which is the amount of increase or decrease in the temperature of the exhaust cooling water, is greater than the threshold value C1 and smaller than the threshold value C2, and the thermostat 35 is either normal or abnormal. When it is difficult to clearly diagnose whether the state is a state, the other of the heat dissipation amount increase control and the heat dissipation amount decrease control can be executed. Thereby, when the diagnosis of the thermostat 35 is possible only by executing the heat dissipation amount reduction control, the diagnosis is completed quickly, and when the clear diagnosis is difficult only by executing the heat dissipation amount decrease control, The accuracy of diagnosis can be improved by executing the heat release increase control.

  Further, in the ECU 10, the diagnosis unit 14 executes at least one of the heat radiation amount decrease control and the heat radiation amount increase control by changing the opening degree of the radiator shutter 38.

  By changing the opening degree of the radiator shutter 38, the flow rate of the air passing through the radiator 36 and the area where heat is exchanged between the discharged cooling water and the air in the radiator 36 can be changed. The ECU 10 can change the opening degree of the radiator shutter 38 to slow or accelerate the heat exchange between the discharged cooling water and the air in the radiator 36, and can execute the heat release amount decrease control or the heat release amount increase control.

  In the first embodiment, the case where the ECU 10 executes the heat radiation amount decrease control and the heat radiation amount increase control by changing the opening degree of the radiator shutter 38 has been described. However, the heat dissipation amount decrease control and the heat dissipation amount increase control are not limited to changing the opening degree of the radiator shutter 38.

  For example, the ECU 10 may execute at least one of the heat radiation amount decrease control and the heat radiation amount increase control by changing the rotational speed of the radiator fan 37.

  In this case, as shown in FIG. 7, the ECU 10 changes the rotational speed of the radiator fan 37 from Nr2 to Nr1 in the heat radiation reduction control. The rotational speed Nr1 is a value smaller than the rotational speed Nr2. Thus, if ECU10 reduces the rotation speed of the radiator fan 37, the flow volume of the air which passes the radiator 36 will decrease, and the heat exchange with the exhaust cooling water and air in the radiator 36 will slow down. As a result, the heat radiation amount of the discharged cooling water in the radiator 36 can be reduced.

  On the other hand, in the heat release amount increase control, as shown in FIG. 7, the ECU 10 changes the rotational speed of the radiator fan 37 from Nr2 to Nr3. The rotational speed Nr3 is a value larger than the rotational speed Nr2. Thus, if ECU10 increases the rotation speed of the radiator fan 37, the flow volume of the air which passes the radiator 36 will increase, and the heat exchange with the exhaust cooling water and air in the radiator 36 will be accelerated | stimulated. As a result, the heat radiation amount of the discharged cooling water in the radiator 36 can be reduced.

  Further, the ECU 10 may execute at least one of the heat radiation amount decrease control and the heat radiation amount increase control by changing the rotation speed of the compressor 44.

  In this case, as shown in FIG. 7, the ECU 10 changes the rotation speed of the compressor 44 from Nc2 to Nc3 in the heat radiation amount reduction control. The rotation speed Nc3 is a value larger than the rotation speed Nc2. Thus, when ECU10 increases the rotation speed of the compressor 44, the temperature of the refrigerant | coolant compressed by the compressor 44 and supplied to the capacitor | condenser 45 will rise. Therefore, as shown by the arrow AF in FIG. 1, the air passing through the condenser 45 becomes relatively high temperature by exchanging heat with the refrigerant.

  As described above, the condenser 45 is provided on the upstream side of the radiator 36 in the air flow direction indicated by the arrow AF. Therefore, in the radiator 36, heat exchange between the exhaust cooling water flowing through the radiator 36 and the relatively high-temperature air that has passed through the condenser 45 is performed. As a result, the heat radiation amount of the discharged cooling water in the radiator 36 can be reduced.

  On the other hand, in the heat release amount increase control, as shown in FIG. 7, the ECU 10 changes the rotation speed of the compressor 44 from Nc2 to Nc1. The rotation speed Nc1 is a value smaller than the rotation speed Nc2. Thus, when the rotation speed of the compressor 44 is decreased, the temperature of the refrigerant compressed by the compressor 44 and supplied to the condenser 45 is lowered. Therefore, as shown by the arrow AF in FIG. 1, the air passing through the condenser 45 becomes relatively low temperature by exchanging heat with the refrigerant.

  Therefore, in the radiator 36, heat exchange between the exhaust cooling water flowing through the radiator 36 and the relatively low temperature air that has passed through the condenser 45 is performed. As a result, it is possible to increase the heat radiation amount of the discharged cooling water in the radiator 36.

  Further, the ECU 10 may execute at least one of the heat radiation amount decrease control and the heat radiation amount increase control by changing the opening degree of the waste gate valve 55.

  In this case, as shown in FIG. 7, the ECU 10 changes the opening degree of the waste gate valve 55 from Dw2 to Dw1 in the heat radiation amount reduction control. The opening degree Dw1 is a value smaller than the opening degree Dw2. When the ECU 10 decreases the opening degree of the waste gate valve 55 in this way, the flow rate of the exhaust gas that is diverted from the first discharge flow path 241 and flows to the second discharge flow path 242 side decreases. That is, the flow rate of exhaust gas passing through the turbine 51 increases. For this reason, the rotation speed of the turbine 51 and the air compressor 52 increases, and the temperature of the air compressed by the air compressor 52 and supplied to the intercooler 54 rises. Therefore, as shown by the arrow AF in FIG. 1, the air passing through the intercooler 54 becomes relatively high in temperature by exchanging heat with the air compressed by the air compressor 52.

  As described above, the intercooler 54 is provided upstream of the radiator 36 in the air flow direction indicated by the arrow AF. Therefore, in the radiator 36, heat exchange is performed between the exhaust cooling water flowing through the radiator 36 and the relatively high-temperature air that has passed through the intercooler 54. As a result, the heat radiation amount of the discharged cooling water in the radiator 36 can be reduced.

  On the other hand, in the heat release increase control, as shown in FIG. 7, the ECU 10 changes the opening degree of the waste gate valve 55 from Dw2 to Dw3. The opening degree Dw3 is a value larger than the opening degree Dw2. When the ECU 10 increases the opening degree of the waste gate valve 55 in this way, the flow rate of the exhaust gas that is diverted from the first discharge flow path 241 and flows to the second discharge flow path 242 side increases. That is, the flow rate of the exhaust gas that passes through the turbine 51 decreases. For this reason, the rotation speed of the turbine 51 and the air compressor 52 decreases, and the temperature of the air compressed by the air compressor 52 and supplied to the intercooler 54 decreases. Therefore, as shown by the arrow AF in FIG. 1, the air passing through the intercooler 54 becomes relatively low in temperature by exchanging heat with the air compressed by the air compressor 52.

  Therefore, in the radiator 36, heat exchange between the discharged cooling water flowing through the radiator 36 and the relatively low temperature air that has passed through the intercooler 54 is performed. As a result, the heat radiation amount of the discharged cooling water in the radiator 36 can be reduced.

  The change of the opening degree of the radiator shutter 38, the change of the rotation speed of the radiator fan 37, the change of the rotation speed of the compressor 44, and the change of the opening degree of the waste gate valve 55 described above may be executed independently. You may perform it combining suitably.

  Next, the ECU 10A according to the second embodiment will be described with reference to FIGS. The ECU 10A is an electronic control device that is mounted on the vehicle 1A and diagnoses the electric valve 35A that is a temperature adjustment valve. Of the vehicle 1A and the ECU 10A, the same components as those of the vehicle 1 and the ECU 10 according to the first embodiment are appropriately denoted by the same reference numerals, and description thereof is omitted.

The electric valve 35 </ b> A is provided at a portion where the bypass flow path 34 branches from the first circulation flow path 331. The electric valve 35A has a valve body (not shown) therein. The valve body is
The electric valve 35A is configured to rotate based on a control signal received from the ECU 10A.

  FIG. 9 is a graph showing the characteristics of the electric valve 35A. On the horizontal axis of the graph, the rotation angle of the valve body provided in the electric valve 35A from a predetermined reference position is plotted. On the vertical axis of the graph, the opening ratio, that is, the opening degree of the electric valve 35A is plotted. A change in the opening degree of the flow path from the electric valve 35A toward the bypass flow path 34 is indicated by a line G10. Further, a change in the opening degree of the flow path from the electric valve 35A toward the first circulation flow path 331 on the radiator 36 side is indicated by a line G20.

  When the rotation angle of the valve body is smaller than d10, both the flow path toward the bypass flow path 34 and the flow path toward the first circulation flow path 331 on the radiator 36 side are closed.

  When the rotation angle of the valve body is increased and becomes larger than d10, only the opening degree of the flow path toward the bypass flow path 34 starts to increase. When the rotation angle further increases to d20, only the flow path toward the bypass flow path 34 is fully opened.

  Further, when the rotation angle increases to d30, the opening degree of the flow path toward the first circulation flow path 331 on the radiator 36 side starts to increase. At this time, the flow path toward the bypass flow path 34 remains fully open. When the rotation angle increases to d40, both the flow path toward the bypass flow path 34 and the flow path toward the first circulation flow path 331 on the radiator 36 side are fully opened.

  Thus, in ECU10A which concerns on 2nd Embodiment, the temperature of the cooling water supplied to the engine 20 is finely adjusted based on the driving | running state of the engine 20 by actively changing the opening degree of each flow path. Can do. However, an abnormality may occur in which the rotation angle of the valve body does not correspond to the signal received from the ECU 10A due to the sticking of the valve body of the electric valve 35A, the signal transmission / reception failure, or the like. The ECU 10A diagnoses the electric valve 35A that operates as described above.

  In the diagnosis of the electric valve 35A, the ECU 10A executes the processes shown in FIGS. 6 and 7 in the same manner as the ECU 10 according to the first embodiment described above. That is, the heat release amount decrease control and the heat release amount increase control are executed, and the electric valve 35A is diagnosed based on the temperature change | ΔTw |

  Note that the ECU 10A performs the above-described heat radiation amount decrease control and heat radiation amount increase control after transmitting a stop signal for stopping the supply of the discharged cooling water to the radiator 36 to the electric valve 35A. That is, the ECU 10A executes the heat radiation amount decrease control and the heat radiation amount increase control after transmitting the control signal to the electric valve 35A so that the rotation angle of the valve body is smaller than d30.

  If the rotation angle of the valve body is d30 or more, the exhaust cooling water is supplied to the radiator 36 even if the electric valve 35A is normal. In such a state, even if the temperature of the discharged cooling water changes due to execution of the heat dissipation amount decrease control or the heat dissipation amount increase control, it cannot be determined whether or not this is due to the abnormality of the electric valve 35A.

  Therefore, as described above, the ECU 10A performs the heat radiation amount decrease control and the heat radiation amount increase control after transmitting a control signal to the electric valve 35A so that the rotation angle of the valve body is smaller than d30. Even if such a control signal is transmitted, if the temperature change of the discharged cooling water is caused by the subsequent execution of the heat dissipation amount decrease control and the heat dissipation amount increase control, the cooling water has been supplied to the radiator 36. Can be estimated. Then, the ECU 10A can diagnose the state of the electric valve 35A based on the temperature change | ΔTw | of the discharged cooling water as in the first embodiment.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. Each element included in each of the specific examples described above and their arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be appropriately changed.

1, 1A: Vehicle 10, 10A: ECU (diagnostic device)
11: Calculation unit (water temperature acquisition unit)
12: Storage unit 14: Diagnosis unit 20: Engine (internal combustion engine)
35: Thermostat (temperature adjustment valve)
35A: Electric valve (temperature control valve)
36: Radiator 37: Radiator fan 38: Radiator shutter (shutter)
44: Compressor 45: Condenser 50: Supercharger 51: Turbine 52: Air compressor 54: Intercooler 55: Waste gate valve

Claims (8)

  A diagnostic device for a temperature regulating valve (35, 35A) for regulating the temperature of cooling water supplied to an internal combustion engine (20) of a vehicle (1, 1A),
  A water temperature acquisition unit (11) for acquiring the temperature of the discharged cooling water that is the cooling water discharged from the internal combustion engine;
  A diagnostic unit (14) for diagnosing the state of the temperature regulating valve based on the temperature of the discharged cooling water,
  The diagnostic unit
The heat dissipation amount reduction control for reducing the heat dissipation amount of the exhaust cooling water in the radiator (36) of the vehicle is executed, and the temperature increase amount of the exhaust cooling water is equal to or higher than the increase threshold based on the execution of the heat dissipation amount reduction control. When it becomes, it diagnoses that the temperature control valve is abnormalWith
After executing the heat dissipation amount reduction control, the heat dissipation amount increase control for increasing the heat dissipation amount of the exhaust cooling water in the radiator is executed, and the temperature decrease amount of the exhaust cooling water based on the execution of the heat dissipation amount increase control When the temperature is equal to or higher than the decrease threshold, the temperature control valve is diagnosed as abnormal,
When the amount of increase in the temperature of the discharged cooling water based on the execution of the heat dissipation amount decrease control is not equal to or higher than the increase threshold value, the heat dissipation amount increase control is executed.
Diagnostic device. As a result of executing one of the heat dissipation amount increase control and the heat dissipation amount decrease control, the diagnostic unit,
When the amount of increase or decrease in the temperature of the discharged cooling water is greater than or equal to the first threshold, the temperature adjustment valve is diagnosed as being abnormal,
Wherein if the increased amount or reduced amount of the temperature of the discharge cooling water is larger than the small and the second threshold value than the first threshold, in Claim 1 for performing the other of said heat radiation amount increase control and the heat dissipation amount reduction control The diagnostic device described. The vehicle is provided with a shutter (38) on the upstream side of the radiator in a flow path of air supplied to the radiator,
The diagnostic apparatus according to claim 1 , wherein the diagnosis unit executes at least one of the heat dissipation amount decrease control and the heat dissipation amount increase control by changing an opening degree of the shutter. The vehicle includes a condenser (45) provided on the upstream side of the radiator in a flow path of air supplied to the radiator, and a compressor (44) that compresses a refrigerant and supplies the refrigerant to the condenser. And
The diagnostic apparatus according to claim 1 , wherein the diagnosis unit executes at least one of the heat radiation amount decrease control and the heat radiation amount increase control by changing a driving state of the compressor. The vehicle is provided with a radiator fan (37) for sending air to the radiator by rotational driving,
The diagnostic apparatus according to claim 1 , wherein the diagnosis unit executes at least one of the heat dissipation amount decrease control and the heat dissipation amount increase control by changing a rotation speed of the radiator fan. The vehicle has a first exhaust passage (241) that guides exhaust gas discharged from the internal combustion engine to a turbine (51) of a supercharger (50), and a first exhaust gas that bypasses the turbine. A discharge gate (242), a waste gate valve (55) for opening and closing the second discharge passage, and an air compressor (52) that rotates together with the turbine and compresses and supplies combustion air to the internal combustion engine ) And an intercooler (54) for cooling the air supplied to the internal combustion engine by the air compressor,
The diagnostic apparatus according to claim 1 , wherein the diagnosis unit executes at least one of the heat release amount decrease control and the heat release amount increase control by changing an opening degree of the waste gate valve. The temperature regulating valve (35A) is configured to operate based on a received signal,
It said diagnostic unit, a stop signal for stopping the supply of the discharge cooling water to the radiator after transmitting to the temperature control valve, to claim 1 to perform at least one of the heat radiation amount reduction control and the heat radiation amount increase control The diagnostic device described.   A diagnostic device for a temperature regulating valve (35, 35A) for regulating the temperature of cooling water supplied to an internal combustion engine (20) of a vehicle (1, 1A),
  A water temperature acquisition unit (11) for acquiring the temperature of the discharged cooling water that is the cooling water discharged from the internal combustion engine;
  A diagnostic unit (14) for diagnosing the state of the temperature regulating valve based on the temperature of the discharged cooling water,
  The diagnostic unit
  While performing the radiation amount reduction | decrease control which reduces the radiation amount of the said cooling water in the radiator (36) of the said vehicle, based on execution of the said radiation amount reduction | decrease control, the increase amount of the temperature of the said exhaust cooling water is more than an increase threshold value When it becomes, while diagnosing that the temperature control valve is abnormal,
  After executing the heat dissipation amount reduction control, the heat dissipation amount increase control for increasing the heat dissipation amount of the exhaust cooling water in the radiator is executed, and the temperature decrease amount of the exhaust cooling water based on the execution of the heat dissipation amount increase control When the temperature is equal to or higher than the decrease threshold, the temperature control valve is diagnosed as abnormal
  As a result of executing one of the heat dissipation amount increase control and the heat dissipation amount decrease control, when the temperature increase or decrease amount of the discharged cooling water is equal to or greater than a first threshold, the temperature adjustment valve is diagnosed as abnormal. When the amount of increase or decrease in the temperature of the discharged cooling water is smaller than the first threshold value and larger than the second threshold value, the other of the heat dissipation amount increase control and the heat dissipation amount decrease control is executed.
  Diagnostic device.

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