JP2017025887A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diagnosis device which can exactly diagnoses a temperature regulation valve even after a finish of the warmup of an engine.SOLUTION: An ECU 10 being a diagnosis device comprises: a calculation part 11 being a water temperature acquisition part which acquires a temperature of exhaust cooling water being cooling water which is discharged from an engine 20; a diagnosis part 141 which compares the temperature of the discharge cooling water and a threshold, and diagnoses a thermostat 45 being a temperature regulation valve; and a reservation part 15 which reserves a diagnosis by the diagnosis part 141. When it is estimated that the temperature of the discharge cooling water becomes lower than the threshold by an operation condition of a vehicle 1 even if the thermostat 45 is normal, the reservation part 15 reserves the diagnosis by the diagnosis part 141.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a diagnostic device for a temperature regulating valve that regulates the temperature of cooling water supplied to an 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. As such a cooling device, what supplies cooling water to an engine by a circulation channel, and cools cooling water (exhaust cooling water) discharged from the engine with a radiator is common.

  On the other hand, when starting the engine, it is required to warm the engine as quickly as possible to a suitable temperature in order to increase the combustion efficiency of the engine (warming up). 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 channel is provided with a thermostat for adjusting the temperature of the cooling water supplied to the engine. The thermostat is a temperature adjustment valve that adjusts the temperature of the cooling water supplied to the engine by opening and closing according to the temperature of the cooling water from the radiator. In order to properly warm up and cool the engine, the thermostat is required to have high reliability.

  The following Patent Document 1 describes a vehicle that diagnoses a thermostat. Specifically, the control device provided in the vehicle measures the temperature of the cooling water during warm-up, and diagnoses the presence or absence of abnormality of the thermostat based on the relationship between the measured temperature and the threshold value. And when the said measured temperature of the cooling water shows the tendency to fall, since the said vehicle may produce a misdiagnosis, the diagnosis of a thermostat is prohibited.

JP-A-2015-78657

  Since the abnormality of the thermostat has a great influence on the engine cooling, it is preferable to perform the diagnosis of the thermostat even after the warm-up is completed. In the above prior art, diagnosis of the thermostat is prohibited when the measured temperature of the cooling water shows a tendency to decrease. When the engine is warmed up, the cooling water is circulated through the radiator and supplied to the engine by the operation of the thermostat, and the temperature of the cooling water fluctuates based on various causes. Therefore, if an attempt is made to diagnose the thermostat simply based on fluctuations in the actual measured temperature of the cooling water, the thermostat cannot be diagnosed accurately if the temperature of the cooling water decreases due to a cause other than the abnormality of the thermostat.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a diagnostic device capable of accurately diagnosing a temperature regulating valve even after completion of engine warm-up.

  In order to solve the above problems, a diagnostic apparatus according to the present invention is a diagnostic apparatus (10) for a temperature adjustment valve (45) that adjusts the temperature of cooling water supplied to an engine (20) of a vehicle (1). A water temperature acquisition unit (11) that acquires the temperature of the discharged cooling water that is the cooling water discharged from the engine, and a diagnosis unit that compares the temperature of the discharged cooling water with a threshold value to diagnose the temperature adjustment valve ( 141) and a holding unit (15) for holding the diagnosis by the diagnosis unit. The holding unit holds the diagnosis by the diagnosis unit when the temperature of the exhaust cooling water is estimated to be lower than the threshold value even if the temperature adjusting valve is normal, due to the operating condition of the vehicle.

  In the diagnostic device according to the present invention, the diagnosis by the diagnosis unit is suspended when it is estimated that the temperature of the discharged cooling water is lower than the threshold value due to the driving condition of the vehicle even if the temperature adjusting valve is normal. Therefore, even when the diagnosis unit diagnoses the temperature adjustment valve by comparing the temperature of the discharged cooling water and the threshold value, the diagnosis of the temperature adjustment valve can be accurately performed.

  According to the present invention, it is possible to provide a diagnostic device capable of accurately diagnosing the temperature regulating valve even after completion of warming up of the engine.

It is a mimetic diagram showing vehicles equipped with ECU concerning an embodiment. It is a functional block diagram which shows ECU of FIG. It is explanatory drawing explaining the driving | operation area | region of the engine of FIG. It is explanatory drawing which shows the decision logic of permission or a holding | maintenance of the thermostat diagnosis by ECU of FIG. It is a time chart which shows the change of the driving | running state of the engine of FIG. 1, and permission or suspension of a thermostat diagnosis. It is a flowchart which shows the process which ECU of FIG. 1 performs. It is a time chart which shows the temperature change of the cooling water accompanying execution of holding cancellation | release promotion control.

  Hereinafter, embodiments 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, an ECU 10 according to an embodiment and a vehicle 1 equipped with the ECU 10 will be described with reference to FIG. The vehicle 1 is a so-called hybrid vehicle equipped with an engine 20 and a traveling motor 30 as power sources.

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

  The traveling motor 30 is an electric motor that generates torque by receiving power. For example, a three-phase AC motor is used as the traveling motor 30 and generates torque based on an electrical signal supplied from the ECU 10. The traveling motor 30 rotates the axle (not shown) of the vehicle 1 with a torque generated alone to cause the vehicle 1 to travel, or generates torque to assist the engine 20 to cause the vehicle 1 to travel. be able to.

  In addition to this, the vehicle 1 is equipped with a cooling device 40 and a heating device 60.

  The cooling device 40 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 40 includes a water pump 41, an engine cooling channel 42, a circulation channel 43, a bypass channel 44, and a radiator 46.

  The water pump 41 is a fluid machine that pumps cooling water. The cooling water contains LLC that is an antifreeze. The water pump 41 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 41, the cooling water supplied from the upstream side of the water pump 41 is pressurized and fed downstream.

  The engine cooling flow path 42 is a cooling water flow path formed inside the engine 20. For example, an engine cooling flow path 42 is formed inside the cylinder block 22 so as to wrap around each cylinder.

  The circulation channel 43 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 42, and the other end is connected to the water pump 41. Thereby, the circulation flow path 43 is a flow path for circulating cooling water to the engine 20 together with the engine cooling flow path 42. The circulation flow path 43 includes a first circulation flow path 431 extending from the downstream end of the engine cooling flow path 42 to a radiator 46 described later, and a second circulation flow path 432 extending from the radiator 46 to the water pump 41.

  The bypass channel 44 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 flow path 431, and the other end is connected in the middle of the pipe forming the second circulation flow path 432. Thereby, the bypass flow path 44 is a flow path that branches from the first circulation flow path 431 and joins in the middle of the second circulation flow path 432 while bypassing the radiator 46.

  The radiator 46 is a heat exchanger provided in the circulation flow path 43. The radiator 46 is formed by alternately laminating metal tubes (not shown) through which cooling water flows and corrugated fins (not shown) formed by bending a metal plate. Air is fed into the radiator 46 from the adjacent radiator fan 47. The air flows between adjacent tubes, passes through the radiator 46, and exchanges heat with the cooling water flowing inside the tubes. Thereby, the cooling water which flows through the radiator 46 is cooled, and the temperature falls.

  The heating device 60 is a device that heats the interior of the vehicle 1. The heating device 60 includes a heater core 61 and a heating blower 62.

  The heater core 61 is a heat exchanger provided in the middle of the bypass flow path 44. The heater core 61 is formed by alternately laminating metal tubes (not shown) through which cooling water flows, and corrugated fins (not shown) formed by bending a metal plate. The heater core 61 is fed with air taken from inside or outside the vehicle by the adjacent heating blower 62. This air flows between adjacent tubes, passes through the heater core 61, and exchanges heat with the cooling water flowing inside the tubes. Thereby, the air which flows between tubes is heated and the temperature rises.

  In addition, a thermostat 45 is arranged at a portion where a pipe forming the bypass flow path 44 branches from a pipe forming the circulation flow path 43. The thermostat 45 has a valve body (not shown), and the valve body is configured to move in response to the temperature of the cooling water in the vicinity thereof. The thermostat 45 is configured to be switched between a closed state and an open state by the movement of the valve body. And the thermostat 45 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 46 and the flow rate of the cooling water supplied to the engine 20 via the bypass channel 44. Adjust the ratio.

  The operation of the cooling device 40 and the heating device 60 configured as described above will be described with reference to FIG.

  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 41 receives an output via the crankshaft and rotates. Thereby, the cooling water in the second circulation channel 432 is pressurized and supplied to the engine cooling channel 42 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 42. 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.

  Since the temperature of the engine 20 is relatively low immediately after the engine 20 is started, the temperature of the cooling water (exhaust cooling water) discharged from the engine cooling flow path 42 and flowing through the first circulation flow path 431 is also compared. Low. In this case, the valve body of the thermostat 45 is disposed at a position that closes the downstream side of the first circulation channel 431 and opens the bypass channel 44 side.

  Thereby, the cooling water discharged from the engine 20 flows through the bypass flow path 44 without being supplied to the radiator 46 and is supplied to the second circulation flow path 432. That is, when the temperature of the engine 20 is relatively low, the cooling water circulates while bypassing the radiator 46. In this case, since the cooling water is not cooled by the radiator 46, the engine 20 is not excessively cooled even if supplied to the engine cooling flow path 42. 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 cooling water discharged from the engine cooling flow path 42 is also relatively high. In this case, the valve body of the thermostat 45 is disposed at a position where both the downstream side of the first circulation channel 431 and the bypass channel 44 are opened.

  Thereby, a part of the cooling water discharged from the engine 20 is supplied to the radiator 46, and the remaining part flows through the bypass flow path 44 and is supplied to the second circulation flow path 432. That is, in a state where the engine 20 is at an appropriate temperature or higher, the cooling water supplied to the radiator 46 is cooled, and the remaining cooling water flows around the radiator 46. These cooling waters merge in the second circulation channel 432, are pressurized by the water pump 41, and are supplied to the engine cooling channel 42 again.

  As described above, the cooling water flowing through the bypass channel 44 exchanges heat with air when passing through the heater core 61. The air heated by this heat exchange and having risen in temperature is guided into the vehicle interior of the vehicle 1 by a duct (not shown) and used for heating the vehicle interior.

  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 51, the outside air temperature sensor 52, the crank angle sensor 53, and the air-fuel ratio sensor 54. The water temperature sensor 51 is a sensor that is disposed in the first circulation flow path 431 (see FIG. 1) and generates and transmits a signal corresponding to the temperature of the cooling water discharged from the engine 20. The outside air temperature sensor 52 is a sensor that is disposed in a part of the vehicle 1 that comes into contact with outside air (see FIG. 1) and generates and transmits a signal corresponding to the outside air temperature. The crank angle sensor 53 is a sensor that generates and transmits a signal corresponding to the angle of the crankshaft of the engine 20. The air-fuel ratio sensor 54 is a sensor that generates and transmits a signal corresponding to the oxygen concentration of the combustion gas discharged from each cylinder of the engine 20.

  The ECU 10 is also electrically connected to each vehicle-mounted device such as the engine 20, the traveling motor 30, the heating blower 62, the radiator fan 47, and the notification device 70. The notification device 70 is a device for performing various notifications to the occupant of the vehicle 1 and is configured by a known device such as a display panel or a buzzer. ECU10 transmits a control signal and controls a drive of each vehicle equipment.

  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, a diagnosis unit 141, a sub-diagnosis unit 142, a holding unit 15, a holding release unit 16, a holding release promotion unit 17, a heat reception amount calculation unit 18, and a heat release amount calculation unit 19. have.

  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 a calculation for generating torque in the engine 20 or the traveling motor 30 in accordance with depression of an accelerator (not shown) by the driver. Moreover, the calculating part 11 performs a predetermined calculation based on the signal received from the water temperature sensor 51, and acquires the temperature of cooling water. Moreover, the calculating part 11 performs a predetermined calculation based on the signal received from the outside temperature sensor 52, and acquires outside temperature. In addition, the calculation unit 11 performs a predetermined calculation based on a signal received from the crank angle sensor 53 and acquires the rotational speed of the engine 20. Further, the calculation unit 11 performs a predetermined calculation based on a signal received from the air-fuel ratio sensor 54, 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.

  The memory | storage part 12 is a part which memorize | stores various information, for example, is comprised by a non-volatile memory. Information such as a map is stored in the storage unit 12 in advance, and 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 141 is a part that diagnoses the thermostat 45. Specifically, the diagnosis unit 141 diagnoses whether there is an abnormality in which the valve body of the thermostat 45 cannot move normally and the above-described closed state and open state cannot be switched.

  The sub-diagnosis unit 142 is a part that diagnoses the thermostat 45 when the diagnosis by the diagnosis unit 141 is suspended. As will be described later, the sub-diagnosis unit 142 diagnoses whether or not there is an abnormality in the thermostat 45 based on the temperature of the cooling water.

  The holding unit 15 is a part that holds the diagnosis by the diagnosis unit 141. As will be described later, when there is a risk of erroneous diagnosis, the holding unit 15 holds the diagnosis of the thermostat 45 by the diagnosis unit 141.

  The holding release unit 16 is a part that releases the holding when the holding unit 15 holds the diagnosis by the diagnosis unit 141. Specifically, the hold releasing unit 16 determines that the possibility of erroneous diagnosis has been resolved based on the rise in the temperature of the cooling water, and releases the hold by the holding unit 15.

  The hold release promoting unit 17 is a part that controls in-vehicle devices such as the engine 20 and the traveling motor 30 so as to promote the release of the hold by the hold release unit 16. Specifically, the hold release promoting unit 17 has at least one of an increase in the amount of heat that the cooling water receives from the outside (heat receiving amount) and a decrease in the amount of heat that the cooling water releases to the outside (heat dissipation amount). The suspension release promotion control for controlling the in-vehicle device is executed.

  The received heat amount calculation unit 18 is a part that calculates the received heat amount of the cooling water. As will be described later, the heat reception amount calculation unit 18 calculates the heat reception amount based on the number of revolutions of the engine 20 and the like.

  The heat dissipation amount calculation unit 19 is a part that calculates the heat dissipation amount of the cooling water. As will be described later, the heat release amount calculation unit 19 calculates the heat release amount based on the outside air temperature or the like.

  Next, the relationship between the operation region of the engine 20 and the amount of heat received by the cooling water will be described with reference to FIG.

  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 region A (the region to which the heat receiving amounts Qrc1 and Qrc2 belong) where the heat receiving amount Qrc of the cooling water is larger than Qrc0, the heat receiving amount Qrc of the cooling water is greater than the heat dissipation amount Qrd. Also grows. In this case, the temperature of the cooling water tends to increase based on the heat balance.

  On the other hand, when the engine 20 is operating in the region B (region to which the heat receiving amount Qrc3 belongs) where the heat receiving amount Qrc of the cooling water is smaller than Qrc0, the heat receiving amount Qrc of the cooling water is larger than the heat dissipation amount Qrd. Get smaller. In this case, the temperature of the 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 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 cooling water discharged from the engine 20 is decreasing, it is determined whether it is due to an abnormality of the thermostat 45 or other causes. It becomes difficult. Therefore, when the thermostat 45 is diagnosed in such a state, there is an increased concern that the diagnosis result is incorrect. When the frequency at which the engine 20 is operating in the B region is high, it is preferable to hold the diagnosis of the thermostat 45.

  Next, referring to FIGS. 4 and 5, the diagnosis permission and suspension determination of the thermostat 45 will be described.

  As shown in FIG. 4, the heat reception amount calculation unit 18 (see FIG. 2) of the ECU 10 displays 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. Match. As a result, the heat receiving amount Qrc of the cooling water in the operating state of the engine 20 is obtained.

  Further, the heat release amount calculation unit 19 (see FIG. 2) of the ECU 10 collates the rotational 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 43 and the bypass flow path 44, and has a correlation with the flow rate of the cooling water. In this embodiment, the water pump 41 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 heat dissipation amount calculation unit 19 calculates a temperature difference ΔT that is a difference between the outside air temperature and the cooling water temperature. The heat dissipation amount calculation unit 19 obtains the heat dissipation amount Qrd of the cooling water by multiplying the temperature difference ΔT 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 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. If this ratio exceeds 50% or more, the engine 20 is frequently operating in the B region, and there is a great concern that the diagnosis result of the thermostat 45 will be incorrect. The diagnosis by the unit 141 is suspended. 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 45 will be incorrect. Therefore, the holding unit 15 of the ECU 10 performs the diagnosis by the diagnosis unit 141. Do not hold (allow diagnosis).

  In FIG. 5, the change between permitting and holding the diagnosis of the thermostat 45 is illustrated along with the change of time. As shown in FIG. 5, from time t0 to time t1, the ECU 10 operates the engine 20 to generate torque T1. Further, 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, the engine 20 does not operate in the B region shown in FIG. 3, so the ratio of the time Trd (B region) to the time length (overall) that the engine 20 is operating is 50. Less than%. In this case, the holding unit 15 of the ECU 10 does not hold the diagnosis by the diagnosis unit 141 (allows the diagnosis).

  When the vehicle 1 shifts to a mode in which the vehicle 1 travels only by the torque generated by the travel motor 30 at time t1, the ECU 1 stops the operation of the engine 20. For this reason, the torque generated by the engine 20 becomes zero at time t1. When no new combustion heat is generated in the engine 20, 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 holding unit 15 of the ECU 10 holds the diagnosis by the diagnosis unit 141. As a result, the diagnosis of the thermostat 45 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 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, the ECU 10 determines whether or not the temperature Tw of the cooling water is lower than a predetermined threshold value. If it is determined that the temperature Tw of the cooling water is not lower than the threshold value (S1: No), the ECU 10 proceeds to the process of step S9 and determines that the diagnosis of the thermostat 45 is not required (diagnosis is permitted). On the other hand, when it is determined in step S1 that the temperature Tw of the cooling water is lower than a predetermined threshold (S1: Yes), the ECU 10 proceeds to the process of step S2.

  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 45 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, ECU10 performs holding | release cancellation promotion control by step S4. As described above, in this on-hold release promotion control, the in-vehicle device is controlled so that at least one of an increase in the amount of heat received by the cooling water and a decrease in the amount of heat released from the cooling water is performed. In the present embodiment, the ECU 10 stops driving the heating blower 62 of the heating device 60. As a result, the amount of heat taken by the cooling water by the air in the heater core 61 is reduced, so that the heat dissipation amount of the cooling water is reduced.

  An example of the temperature Tw of the cooling water when the hold release promotion control is executed in this way is shown in FIG. In FIG. 7, the cooling water temperature Tw and its time differential value when the thermostat 45 is abnormal are indicated by a solid line, and the cooling water temperature Tw and its time differential value when the thermostat 45 is normal are indicated by a broken line. Has been.

  It is assumed that when the temperature Tw of the coolant immediately after holding the diagnosis of the thermostat 45 is Tw1, the ECU 10 executes the above-described hold release promotion control from time t3 to time t4. In this case, since the heat dissipation amount of the cooling water decreases, the temperature Tw of the cooling water tends to increase if the thermostat 45 is normal. On the other hand, when there is an abnormality in the thermostat 45, the temperature Tw of the cooling water at the portion where the water temperature sensor 51 is arranged is not affected even if the above-described hold release promotion control is executed.

  Here, the ECU 10 determines that the temperature Tw of the cooling water has changed normally if the temperature Tw of the cooling water is equal to or higher than the threshold value Tw0 as a result of the suspension release promotion control. Alternatively, it may be determined that the temperature Tw of the cooling water has changed normally when the time differential value of the temperature Tw of the cooling water is equal to or greater than the threshold A0.

  This will be described with reference to FIG. 6 again. In the next step S5, the ECU 10 determines whether or not the cooling water temperature has changed normally as a result of executing the hold release promotion control. As shown by a broken line in FIG. 7, when the temperature Tw of the cooling water shows an increasing tendency due to the execution of the hold release promotion control (S5: Yes), the ECU 10 proceeds to step S8 and performs the diagnosis of the thermostat 45. Release the hold and restart the diagnosis. On the other hand, in the case where the temperature Tw of the cooling water does not show a rising tendency as shown by the solid line in FIG. 7 even though the suspension cancellation promotion control is executed (S5: No), the ECU 10 performs the process of step S6. move on.

  Next, the ECU 10 diagnoses that the thermostat 45 is abnormal in step S6. Based on this diagnosis, the ECU 10 can operate the notification device 70 in the next step S7 to prompt the user of the vehicle 1 to perform an inspection or the like.

  On the other hand, when it determines with the ratio which the engine 20 is drive | operating in B area | region not being 50% or more by step S2 (S2: No), ECU10 progresses to the process of step S6, S7. That is, even when the temperature Tw of the cooling water is lower than the threshold value, this is not caused by the fact that the engine 20 is frequently operated in the B region, it can be determined that the thermostat 45 is abnormal. Therefore, also in this case, the ECU 10 operates the notification device 70 and prompts the user of the vehicle 1 to perform an inspection or the like.

  As described above, the ECU 10 according to the present embodiment performs diagnosis by the diagnosis unit 141 when it is estimated that the temperature of the exhaust cooling water is lower than the threshold value due to the operation condition of the vehicle 1 even if the thermostat 45 is normal. Hold. Therefore, according to the ECU 10, when the vehicle 1 is operating under an operating condition in which the temperature of the discharged cooling water decreases due to a reason other than the abnormality of the thermostat 45 after the warm-up of the engine 20 is completed, the diagnosis by the diagnosis unit 141 is suspended. Thus, the thermostat 45 can be diagnosed accurately.

  In addition, the ECU 10 receives a heat receiving amount calculation unit 18 that calculates a heat receiving amount Qrc of the cooling water after the engine 20 has been warmed up, and a heat releasing amount calculation unit that calculates a heat dissipation amount Qrd of the cooling water after the engine 20 has been warmed up. 19. The holding unit 15 holds the diagnosis by the diagnosis unit 141 when the heat release amount Qrd calculated by the heat release amount calculation unit 19 is larger than the heat reception amount Qrc calculated by the heat reception amount calculation unit 18.

  According to this configuration, based on the fact that the heat dissipation amount Qrd is larger than the heat receiving amount Qrc, it is possible to estimate that the temperature of the discharged cooling water is lowered even if the thermostat 45 is normal. Therefore, when the heat radiation amount Qrd is larger than the heat reception amount Qrc, the diagnosis of the thermostat 45 can be accurately performed by holding the diagnosis by the diagnosis unit 141.

  Further, the heat receiving amount calculation unit 18 calculates the heat receiving amount Qrc of the cooling water in a predetermined period after the completion of warming up of the engine 20, and the heat dissipation amount calculating unit 19 receives the cooling water heat receiving amount Qrc in the predetermined period. Is calculated.

  According to this configuration, by setting so as to calculate the heat receiving amount Qrc and the heat receiving amount Qrc of the cooling water in the predetermined period, the thermostat 45 is normal while reducing the processing load of the ECU 10. Even if it exists, it becomes possible to estimate that the temperature of discharge cooling water falls.

  In addition, the holding unit 15 is a time during which the heat release amount Qrd calculated by the heat release amount calculation unit 19 in the predetermined period is larger than the heat reception amount Qrc calculated by the heat reception amount calculation unit 18 with respect to the time length of the predetermined period. When the Trd ratio is greater than 50%, the diagnosis by the diagnosis unit 141 is suspended.

  According to this configuration, the ratio of the time Trd in which the heat dissipation amount Qrd is greater than the heat reception amount Qrc with respect to the time length of the predetermined period is greater than 50%, so that even if the thermostat 45 is normal, the discharge is performed. It is possible to estimate that the temperature of the cooling water decreases. Therefore, when the ratio is larger than 50%, the diagnosis of the thermostat 45 can be accurately performed by withholding the diagnosis by the diagnosis unit 141.

  Further, the ECU 10 includes a hold release unit 16 that releases the hold by the hold unit 15 based on the rise in the temperature of the discharged cooling water.

  According to this configuration, when the temperature of the discharged cooling water rises to a level at which there is little concern that erroneous diagnosis will be performed, the diagnosis suspension of the diagnosis unit 141 can be released and the diagnosis of the thermostat 45 can be resumed. Become.

  In addition, when the diagnosis by the diagnosis unit 141 is suspended, the ECU 10 performs the suspension release promotion control that performs at least one of the increase in the heat receiving amount Qrc of the cooling water and the decrease in the heat dissipation amount Qrd of the cooling water. A release promoting unit 17 is provided.

  According to this configuration, the temperature of the exhaust cooling water can be positively increased, and the diagnosis of the thermostat 45 by the diagnosis unit 141 can be restarted quickly.

  The ECU 10 also includes a sub-diagnosis unit 142 that diagnoses the thermostat 45 when the diagnosis by the diagnosis unit 141 is suspended. The sub-diagnosis unit 142 diagnoses that there is an abnormality in the thermostat 45 when the temperature of the discharged cooling water does not rise even when the hold release promoting unit 17 executes the hold release promoting control.

  According to this configuration, it is possible to diagnose whether or not there is an abnormality in the thermostat 45 based on the temperature change of the discharged cooling water at that time while attempting to resume the diagnosis of the thermostat 45 by executing the hold release promotion control. .

  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.

  For example, in the above embodiment, the hold release promoting unit 17 stops driving the heating blower 62 of the heating device 60 as the hold release promoting control, but the present invention is not limited to this. That is, the hold release promotion unit 17 increases the heat receiving amount Qrc of the cooling water by prohibiting the idle stop operation in which the fuel supply to the engine 20 is stopped while the vehicle 1 is stopped as the hold release promotion control. May be.

  Such idle stop driving is widely used as one of the measures for improving the fuel consumption of the vehicle 1. During the idling stop operation, no new combustion heat is generated in the engine 20, so the heat receiving amount Qrc of the cooling water decreases.

  On the other hand, by prohibiting the idling stop operation as the hold release promotion control, the fuel is supplied to the engine 20 even when the vehicle 1 is stopped. Therefore, new combustion heat is generated and the received heat amount Qrc of the cooling water. Can be increased. As a result, the temperature of the discharged cooling water is raised, and the diagnosis of the thermostat 45 by the diagnosis unit 141 can be restarted quickly.

  In addition, the hold release promoting unit 17 may increase the heat receiving amount Qrc of the cooling water by increasing the rotation speed of the engine 20 while the vehicle 1 is stopped as the hold release promoting control.

  In order to increase the rotational speed of the engine 20 while the vehicle 1 is stopped, it is necessary to increase the fuel supplied to the engine 20. By supplying a large amount of fuel to the engine 20, it is possible to generate a larger amount of combustion heat and increase the heat receiving amount Qrc of the cooling water. As a result, the temperature of the discharged cooling water is raised, and the diagnosis of the thermostat 45 by the diagnosis unit 141 can be restarted quickly.

  Further, the hold release promoting unit 17 may increase the heat receiving amount Qrc of the cooling water by suppressing the fuel cut operation that stops the fuel supply to the engine 20 while the vehicle 1 is traveling.

  A fuel cut operation in which the fuel supply to the engine 20 is stopped while the vehicle 1 is traveling is also widely used as one of the measures for improving the fuel consumption of the vehicle 1. During this fuel cut operation, no new combustion heat is generated in the engine 20, so the amount of heat Qrc received by the cooling water decreases.

  In contrast, the hold release promoting unit 17 suppresses the fuel cut operation as the hold release promoting control so that the fuel is supplied to the engine 20, so that new combustion heat is generated and the amount of cooling water received Qrc. Can be increased. As a result, the temperature of the discharged cooling water is raised, and the diagnosis of the thermostat 45 by the diagnosis unit 141 can be restarted quickly.

  Further, the hold release promoting unit 17 may increase the amount of heat received in the cooling water by suppressing the driving of the driving motor 30 that assists the engine 20 by generating driving torque while the vehicle 1 is driving. Good.

  In the state where the vehicle 1 is traveling by the torque generated by the engine 20 and the traveling motor 30, it is necessary to supply the engine 20 to the state where the vehicle 1 is traveling only by the torque generated by the engine 20. There will be less fuel. For this reason, the combustion heat generated in the engine 20 is also reduced, and the heat receiving amount Qrc of the cooling water is reduced.

  On the other hand, since the amount of fuel supplied to the engine 20 is increased by suppressing the driving of the traveling motor 30 as the hold release promotion control by the hold release promotion unit 17, a large amount of combustion heat is generated to generate cooling water. The amount of heat received Qrc can be increased. As a result, the temperature of the discharged cooling water is raised, and the diagnosis of the thermostat 45 by the diagnosis unit 141 can be restarted quickly.

  Further, the hold release promoting unit 17 may increase the heat reception amount Qrc of the cooling water by retarding the fuel ignition timing in the engine 20.

  The hold release promoting unit 17 retards the fuel ignition timing in the engine 20 as the hold release promoting control, so that the conversion efficiency to kinetic energy in the engine 20 can be reduced and the thermal energy can be increased. As a result, the temperature of the discharged cooling water is raised, and the diagnosis of the thermostat 45 by the diagnosis unit 141 can be restarted quickly.

1: Vehicle 10: ECU (diagnostic device)
11: Calculation unit (water temperature acquisition unit)
141: Diagnosis unit 142: Sub-diagnosis unit 15: Reservation unit 16: Retention cancellation unit 17: Retention cancellation promotion unit 18: Heat reception amount calculation unit 19: Heat release amount calculation unit 20: Engine 30: Motor for travel (electric motor)
43: Circulating channel 44: Bypass channel 45: Thermostat (temperature control valve)
46: Radiator 60: Heating device

Claims (13)

A diagnostic device (10) for a temperature regulating valve (45) for regulating the temperature of cooling water supplied to an engine (20) of a vehicle (1),
A water temperature acquisition unit (11) for acquiring the temperature of the discharged cooling water that is the cooling water discharged from the engine;
A diagnostic unit (141) for diagnosing the temperature adjustment valve by comparing the temperature of the discharged cooling water with a threshold value;
A holding unit (15) for holding the diagnosis by the diagnosis unit,
The holding unit holds the diagnosis by the diagnosis unit when it is estimated that the temperature of the discharged cooling water is lower than the threshold value even if the temperature adjustment valve is normal due to the operating condition of the vehicle. Diagnostic device featuring. A heat receiving amount calculation unit (18) for calculating a heat receiving amount of the cooling water after the engine is warmed up;
A heat release amount calculation unit (19) that calculates the heat release amount of the cooling water after the engine is warmed up,
The said holding | maintenance part suspends the diagnosis by the said diagnostic part, when the heat radiation amount calculated by the said heat radiation amount calculation part is larger than the heat reception amount calculated by the said heat reception amount calculation part. The diagnostic device according to 1. The heat receiving amount calculation unit calculates a heat receiving amount of cooling water in a predetermined period after completion of warming up of the engine,
The diagnostic apparatus according to claim 2, wherein the heat radiation amount calculation unit calculates a heat reception amount of the cooling water in the predetermined period.   The ratio of the length of time that the holding unit is in a state in which the heat release amount calculated by the heat release amount calculation unit in the predetermined period is larger than the heat reception amount calculated by the heat reception amount calculation unit with respect to the time length of the predetermined period The diagnosis apparatus according to claim 3, wherein the diagnosis by the diagnosis unit is suspended when the value is larger than a predetermined value.   The diagnostic apparatus according to claim 4, further comprising a hold release unit that releases the hold by the hold unit based on an increase in the temperature of the discharged cooling water.   When the diagnosis by the diagnosis unit is on hold, a hold release promoting unit (17) that performs hold release promoting control that performs at least one of an increase in the amount of heat received by the cooling water and a decrease in the amount of heat released from the cooling water is provided. The diagnostic apparatus according to claim 5.   The said holding | maintenance cancellation | release promotion part increases the heat-receiving amount of a cooling water by prohibiting the idle stop driving | operation which stops the fuel supply to the said engine while the said vehicle stops. Diagnostic device.   The diagnostic apparatus according to claim 6, wherein the hold release promoting unit increases the amount of heat received by the cooling water by increasing the number of revolutions of the engine while the vehicle is stopped.   The said holding | maintenance cancellation | release promotion part increases the heat receiving amount of a cooling water by suppressing the fuel cut driving | operation which stops the fuel supply to the said engine during driving | running | working of the said vehicle. Diagnostic device.   The hold release promoting unit increases a heat receiving amount of the cooling water by generating driving torque while the vehicle is running and suppressing driving of the electric motor (30) that assists the engine. The diagnostic device according to claim 6.   The diagnostic apparatus according to claim 6, wherein the holding release promoting unit increases the amount of heat received by the cooling water by retarding a fuel ignition timing in the engine.   The said hold cancellation | release promotion part reduces the heat dissipation of a cooling water by suppressing the driving | operation of the heating apparatus (60) which heats the vehicle interior of the said vehicle using a cooling water as a heat source. The diagnostic device according to 1. A sub-diagnosis unit (142) for diagnosing the temperature control valve when diagnosis by the diagnosis unit is suspended;
The sub-diagnosis unit diagnoses that there is an abnormality in the temperature control valve when the temperature of the exhaust cooling water does not rise even when the hold release promoting unit executes the hold release promoting control. Item 7. The diagnostic device according to Item 6.

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