JP2011073644A - Control device - Google Patents

Abstract

A control device that efficiently performs power feeding control of a heating wire disposed in a vehicle window and prevents wasteful power consumption is provided.
When power supply control to a heat wire 10 arranged in a rear window 101 is performed, a current and a voltage flowing through the heat wire 10 when energized are detected, and the current and voltage change, for example, in time series based on the detected current and voltage. The amount of change in the resistance value of the hot wire 10 is calculated. Based on the calculated change amount of the resistance value, the temperature rise degree of the heat wire 10 is calculated, and when the temperature rise degree is equal to or greater than a predetermined value, the power supply to the heat wire 10 is stopped.
[Selection] Figure 1

Description

  The present invention relates to a control device that performs power supply control to a heating wire arranged in a vehicle window in order to prevent fogging of the vehicle window due to condensation, frost formation, freezing, or the like.

  A vehicle window may be cloudy or frozen due to a temperature difference between the inside and outside of the vehicle, and the occupant's view may be blocked. For this reason, the vehicle is provided with a so-called defogger. The defogger mainly removes fogging of the window by causing a current to flow through a heating wire attached to the rear window to generate heat. Thereby, a passenger | crew's visual field is ensured.

  Since the defogger consumes more power than other in-vehicle devices, there has been proposed a device that effectively removes fogging of a window and the like and suppresses wasteful power consumption (see, for example, Patent Document 1). The apparatus described in Patent Document 1 estimates the ambient temperature of the rear window based on the temporal change amount of the current flowing through the heat wire heater (heating wire), and intermittently supplies current to the heat wire heater based on the estimation result. Is configured to supply. With this configuration, heating suitable for the ambient temperature of the window is possible, and power consumption is reduced by avoiding excessive energization.

JP 2006-151285 A

  However, as described in Patent Document 1, there is a possibility that the accurate ambient temperature of the rear window cannot be estimated from the amount of change in the current flowing through the hot wire heater. In this case, even if the current is intermittently supplied to the hot wire heater, the fogging of the rear window may not be sufficiently removed. Therefore, the present inventor can appropriately calculate the temperature related to the heating wire by using the current and voltage flowing in the heating wire, and as a result, it is possible to realize more efficient anti-fogging and the like with power saving. Obtained knowledge.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a control device that efficiently performs power feeding control of a heating wire arranged in a vehicle window and prevents wasteful power consumption. is there.

  The control device according to the present invention is a control device that performs power feeding control to a heating wire arranged in a vehicle window, based on the means for detecting the current and voltage flowing through the heating wire when energized, and the detected current and voltage, It is characterized by comprising a calculating means for calculating the temperature relating to the heating wire, and a stopping means for stopping the power supply to the heating wire based on the calculated temperature.

  In the present invention, power supply to the heating wire is stopped based on the temperature related to the heating wire calculated based on the current and voltage flowing in the heating wire arranged in the vehicle window. When the temperature related to the heating wire reaches a temperature sufficient for, for example, removing or preventing fogging of the vehicle window, wasteful power consumption can be prevented by stopping power feeding.

  The control device according to the present invention is adapted to calculate the current and voltage flowing in the heating wire over time, and based on the detected current and voltage, means for calculating the resistance value of the heating wire over time And a means for calculating a change amount of the calculated resistance value, wherein the calculation means calculates a temperature difference at the time when the resistance value related to the change amount is calculated based on the calculated change amount of the resistance value. The stopping means is characterized in that power supply is stopped when the calculated temperature difference is equal to or greater than a predetermined value.

  In the present invention, when the resistance value of the power line changes as a result of the temperature change due to energization, the change amount of the resistance value is calculated, and the temperature difference is calculated based on the calculated change amount. Then, when the temperature difference is greater than or equal to a predetermined value, power feeding is stopped. By calculating the temperature change from the resistance value change, it is possible to calculate the temperature related to the heating wire more accurately. As a result, power feeding control of the heating wire can be performed efficiently and wasteful power consumption can be prevented.

  The control device according to the present invention further includes means for calculating a resistance value of the heating wire based on the detected current and voltage, and means for acquiring an in-vehicle temperature and an outside temperature, wherein the calculating means calculates Based on the resistance value of the heating wire, the temperature of the heating wire is calculated, and the stopping unit stops power supply when the calculated temperature of the heating wire is equal to or higher than the acquired in-vehicle temperature and outside temperature. It is characterized by the above.

  In the present invention, the temperature of the heating wire is calculated based on the resistance value calculated from the current and voltage flowing in the heating wire, and the power feeding is stopped when the calculated temperature becomes equal to or higher than the vehicle interior temperature and the vehicle exterior temperature. . Thereby, it can prevent that fogging generate | occur | produces in a vehicle window, after stopping the electric power feeding to a heating wire.

  The control device according to the present invention further includes means for measuring an elapsed time after the start of power supply to the heating wire, and the stop means is configured to stop power supply when a predetermined time has elapsed from the start of power supply, When the temperature difference is equal to or higher than a predetermined value, or when the temperature of the heating wire is equal to or higher than the vehicle interior temperature and temperature, further includes means for intermittently supplying power to the heating wire until a predetermined time elapses from the start of power supply. It is characterized by that.

  In the present invention, by intermittently supplying power before the vehicle stops, it is possible to prevent the vehicle window from becoming cloudy again after removing clouding or the like.

  The present invention stops power feeding to the heating wire based on the temperature related to the heating wire calculated based on the current and voltage flowing in the heating wire arranged in the vehicle window. When the temperature related to the heating wire reaches a temperature sufficient for, for example, removing or preventing fogging of the vehicle window, wasteful power consumption can be prevented by stopping power feeding.

1 is a perspective view schematically showing a vehicle equipped with a defogger device according to Embodiment 1. FIG. FIG. 3 is a block diagram illustrating an electrical configuration of the defogger device according to the first embodiment. 4 is a flowchart illustrating processing executed by the defogger apparatus according to the first embodiment. 6 is a block diagram illustrating an electrical configuration of a defogger apparatus according to Embodiment 2. FIG. 10 is a flowchart illustrating processing executed by the defogger apparatus according to the second embodiment. 10 is a flowchart illustrating processing executed by the defogger apparatus according to the third embodiment. 10 is a flowchart illustrating processing executed by the defogger apparatus according to the fourth embodiment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a control device according to the invention will be described with reference to the drawings. In the embodiments described below, the control device according to the present invention will be described as a defogger device mounted on a vehicle.

(Embodiment 1)
FIG. 1 is a perspective view schematically showing a vehicle on which the defogger device according to the first embodiment is mounted. The defogger apparatus according to the first embodiment includes a hot wire 10 embedded over substantially the entire rear window 101 of the vehicle 100. The hot wire 10 is a resistance heating element that is energized and generates heat when the defogger device is turned on. The heat wire 10 generates heat to heat the rear window 101. As a result, the defogger apparatus prevents fogging of the rear window 101 due to condensation, frost formation or freezing.

  FIG. 2 is a block diagram illustrating an electrical configuration of the defogger apparatus according to the first embodiment.

  The defogger device includes an ECU (Electronic Control Unit) 1, a power feeding circuit 2, a switch 3, a current sensor 4, a voltage sensor 5, and the like. The power supply circuit 2 includes a relay switch, for example, and is on / off controlled by the ECU 1 to supply a predetermined voltage to the heat wire 10 and stop the power supply. The switch 3 is a switch for the driver to turn on and off the defogger device, and is disposed, for example, at a predetermined position on an instrument panel (not shown). The current sensor 4 and the voltage sensor 5 detect a current flowing through the heat wire 10 and a voltage applied to the heat wire 10. The current sensor 4 and the voltage sensor 5 may detect a current and a voltage flowing through the entire heat wire 10, or may detect a current and a voltage flowing through a part thereof.

  The ECU 1 is mainly configured by a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown). And ECU1 controls operation | movement of the whole defogger apparatus by performing operation control of each part connected with the bus | bath, when CPU runs the control program stored in ROM.

  The ECU 1 supplies power to the hot wire 10 by turning on and off a switch included in the power supply circuit 2 and stops power supply. For example, when the switch 3 is turned on, the ECU 1 starts feeding, and when the switch 3 is turned off, the ECU 1 stops feeding. The ECU 1 has a timer function. When a predetermined time (for example, 10 minutes) has elapsed since the switch 3 was turned on, the ECU 1 stops power feeding. Note that the power feeding circuit 2 may be provided with a timer function so that the power feeding circuit 2 measures the time and stops power feeding.

  Further, in the first embodiment, the ECU 1 estimates the temperature rise of the hot wire 10 and stops power supply when the hot wire 10 reaches a predetermined temperature. Hereinafter, the temperature estimation method in Embodiment 1 will be described.

  After the switch 3 is turned on and power supply to the heat wire 10 is started via the power supply circuit 2, the ECU 1 determines the resistance value R (of the heat wire 10 based on the current I and the voltage V detected by the current sensor 4 and the voltage sensor 5. = V / I) is calculated. When the hot wire 10 is energized, the temperature rises with time, so the resistance value R of the hot wire 10 changes with time. The ECU 1 calculates the resistance value R as needed, and calculates the change amount ΔR of the resistance value R that changes.

  The change amount ΔR is a change amount based on the resistance value Rint of the hot wire 10 at the start of energization, and is calculated by ΔR = R−Rint. The resistance value Rint is the resistance value of the hot wire 10 when a current equal to or greater than the threshold value (current Ith) flows through the hot wire 10 after the start of energization. The resistance value Rint may be the resistance value of the hot wire 10 when a predetermined time has elapsed since the start of energization.

The ECU 1 calculates the temperature rise degree ΔT of the hot wire 10 based on the calculated change amount ΔR of the resistance value. The temperature rise degree ΔT is a difference between the temperature T of the hot wire 10 at the resistance value R of the hot wire 10 changed by the temperature rise and the temperature Tint of the hot wire 10 at the resistance value Rint, and ΔT = T−Tint. Here, the resistance value R of the hot wire 10 can be expressed as R = R ₀ * {1 + α (T−T ₀ )}. R ₀ is the resistance value of the heat ray at 0 ° C. (for example, 2Ω), T ₀ is 0 (° C.), and T is the temperature of the heat ray. Α is a temperature coefficient (for example, 0.004). Then, the amount of change ΔR becomes ΔR = R−Rint = R ₀ * α (T−Tint). Therefore, the temperature rise degree ΔT can be calculated by ΔT = T−Tint = ΔR / β (β: coefficient).

  The ECU 1 turns off the defogger device when the calculated temperature rise ΔT reaches a predetermined value Tth. That is, the ECU 1 causes the power supply circuit 2 to stop supplying power to the heat wire 10 when the heat wire 10 rises in temperature Tth after being energized. At this time, the ECU 1 is turned off even if the predetermined time has not elapsed since the switch 3 was turned on. Thereby, after cloudiness is removed and a field of view is secured, energization to the hot wire can be stopped quickly, and wasteful power consumption can be prevented.

  An operation in the defogger apparatus configured as described above will be described. FIG. 3 is a flowchart illustrating processing executed by the defogger apparatus according to the first embodiment. The process shown in FIG. 3 is executed by the ECU 1.

  The ECU 1 determines whether or not the switch 3 is turned on (S1). If it is not turned on (S1: NO), the ECU 1 waits until it is turned on. When turned on (S1: YES), the ECU 1 causes the power feeding circuit 2 to start power feeding to the heat wire 10 (S2), starts a timer, and starts counting (S3). The ECU 1 acquires the current I and the voltage V detected by the current sensor 4 and the voltage sensor 5 (S4), and determines whether or not the current I is equal to or greater than the current Ith (S5). When the current I is not equal to or greater than the current Ith (S5: NO), the ECU 1 executes S4 again.

  When the current I becomes equal to or greater than the current Ith (S5: YES), the ECU 1 calculates a resistance value Rint (S6). The resistance value Rint is calculated from the voltage V / current I. The ECU 1 stores the calculated resistance value Rint in a RAM or the like.

  Next, the ECU 1 acquires the current I and the voltage V detected by the current sensor 4 and the voltage sensor 5 (S7), and calculates a resistance value R (S8). The ECU 1 calculates the temperature rise degree ΔT based on the resistance value Rint and the resistance value R (S9). The ECU 1 determines whether or not the calculated temperature rise ΔT is equal to or greater than a predetermined value Tth (S10). When the temperature rise ΔT is equal to or greater than the predetermined value Tth (S10: YES), the ECU 1 causes the power feeding circuit 2 to stop power feeding to the heat wire 10 (S12). As a result, the defogger device is turned off, and the ECU 1 ends this process.

  If the temperature increase ΔT is not equal to or greater than the predetermined value Tth (S10: NO), the ECU 1 determines whether or not a predetermined time has elapsed since the timer was started in S3 (S11). When the predetermined time has not elapsed (S11: NO), the ECU 1 returns the process to S7. When the predetermined time has elapsed (S11: YES), the ECU 1 causes the power feeding circuit 2 to stop power feeding (S12), and ends this processing.

  As described above, in the first embodiment, the temperature rise degree ΔT of the hot wire 10 is calculated from the change amount ΔR of the resistance value of the hot wire 10, and when the temperature rise degree ΔT is equal to or greater than the predetermined value Tth, power is supplied to the hot wire 10. Has stopped. Thereby, even if the fogging of the rear window 101 is removed, it is possible to avoid power consumption due to continuing to supply power to the hot wire 10 until a predetermined time elapses.

(Embodiment 2)
Embodiment 2 according to the present invention will be described below. The second embodiment is different from the first embodiment in that the temperature of the hot wire 10 is calculated and the defogger device is turned off based on the calculated temperature and the temperature inside and outside the vehicle. Hereinafter, differences from the first embodiment will be described.

  FIG. 4 is a block diagram illustrating an electrical configuration of the defogger apparatus according to the second embodiment. In the second embodiment, the defogger apparatus includes a vehicle interior temperature sensor 6 and a vehicle exterior temperature sensor 7 in addition to the configuration of the first embodiment. The ECU 1 acquires the temperatures detected by the vehicle interior temperature sensor 6 and the vehicle exterior temperature sensor 7. In the second embodiment, the defogger device includes the vehicle interior temperature sensor 6 and the vehicle exterior temperature sensor 7. However, the defogger device is configured to acquire the temperature from the vehicle interior temperature sensor and the vehicle exterior temperature sensor that are already mounted on the vehicle 100. May be.

The ECU 1 calculates the temperature T of the hot wire 10 at the resistance value R of the hot wire 10 that has changed due to the temperature rise. As described in the first embodiment, the resistance value R of the hot wire 10 that has changed due to the temperature rise is expressed as R = R ₀ * {1 + α (T−T ₀ )}. Therefore, the temperature T of the hot wire 10 is calculated by T = (R / R ₀ −1) / α + T ₀ .

  The ECU 1 turns off the defogger device when the calculated temperature T of the hot wire 10 is equal to or higher than the outside temperature and the inside temperature detected by the inside temperature sensor 6 and the outside temperature sensor 7. That is, the ECU 1 causes the power supply circuit 2 to stop supplying power to the heat wire 10. By performing power supply control according to the outside temperature and the inside temperature, power supply to the hot wire 10 can be stopped immediately after the fogging of the rear window 101 is removed under any temperature environment. Consumption can be prevented.

  The operation in the defogger apparatus according to the second embodiment will be described below. FIG. 5 is a flowchart illustrating processing executed by the defogger apparatus according to the second embodiment.

  The ECU 1 determines whether or not the switch 3 is turned on (S20). If it is not turned on (S20: NO), the ECU 1 waits until it is turned on. When turned on (S20: YES), the ECU 1 causes the power feeding circuit 2 to start power feeding to the heat wire 10 (S21), starts a timer, and starts counting (S22). The ECU 1 acquires the current I and the voltage V detected by the current sensor 4 and the voltage sensor 5 (S23), and determines whether or not the current I is equal to or greater than the current Ith (S24). When the current I is not equal to or greater than the current Ith (S24: NO), the ECU 1 executes S23 again.

  When the current I becomes equal to or greater than the current Ith (S24: YES), the ECU 1 calculates a resistance value Rint (S25). Next, the ECU 1 acquires the current I and the voltage V detected by the current sensor 4 and the voltage sensor 5, and the vehicle interior temperature Tin and the vehicle exterior temperature Tout detected by the vehicle interior temperature sensor 6 and the vehicle exterior temperature sensor 7 (S26). The ECU 1 calculates a resistance value R from the acquired current I and voltage V (S27). The ECU 1 calculates the temperature T based on the calculated resistance value Rint and the resistance value R (S28). The ECU 1 determines whether or not the calculated temperature T is equal to or higher than the vehicle interior temperature Tin and the vehicle exterior temperature Tout (S29).

  When the temperature is equal to or higher than the vehicle interior temperature Tin and the vehicle exterior temperature Tout (S29: YES), the ECU 1 causes the power supply circuit 2 to stop power supply to the heat wire 10 (S30). As a result, the defogger device is turned off, and the ECU 1 ends this process. When the temperature T is not equal to or higher than the vehicle interior temperature Tin and the vehicle exterior temperature Tout (S29: NO), the ECU 1 determines whether or not a predetermined time has elapsed since the timer was started in S22 (S31). If the predetermined time has not elapsed (S31: NO), the ECU 1 returns the process to S26. When the predetermined time has elapsed (S31: YES), the ECU 1 causes the power feeding circuit 2 to stop power feeding (S30), and ends this processing.

  As described above, in the second embodiment, the temperature T of the hot wire 10 is calculated from the change amount ΔR of the resistance value of the hot wire 10. Then, power is supplied to the heat wire 10 with the outside temperature and the inside temperature as target temperatures, and when the calculated temperature T becomes equal to or higher than the outside temperature Tin and the outside temperature Tout, the power supply to the heat wire 10 is stopped. Thereby, it is possible to prevent the power consumption from increasing by continuing to supply power even after the condensation of the rear window 101 is removed.

(Embodiment 3)
Embodiment 3 according to the present invention will be described below. In the third embodiment, the method for calculating the temperature rise ΔT is different from that in the first embodiment. Further, the third embodiment is different from the first embodiment in that when the temperature rise degree ΔT reaches a predetermined value Tth, the hot wire 10 is subjected to PWM (Pulse Width Modulation) control. Hereinafter, differences from the first embodiment will be described.

The configuration of the defogger apparatus according to the third embodiment is the same as that of the first embodiment. In the third embodiment, the ECU 1 calculates the temperature increase ΔT by the following formula (1) or formula (2). In the equations (1) and (2), Δt is 1 s, τ is 120 s, R _th1 is 0.15 (K / W), and R _th2 is 0.064 (K / V ² ). N is a natural number.

  When the calculated temperature rise ΔT reaches the predetermined value Tth, the ECU 1 causes the power feeding circuit 2 to perform PWM control of the hot wire 10. At this time, the ECU 1 calculates a voltage Vpwm in the PWM control. When the temperature rise ΔT becomes a predetermined value Tth, the equation (2) can be expressed as the following equation (3).

  When the voltage V in the equation (3) is the voltage Vpwm at the time of PWM control, the equation (3) is expressed as the following equation (4), and the voltage Vpwm is calculated from the equation (4).

  The ECU 1 controls the power feeding circuit 2 so that the calculated voltage Vpwm is obtained, and executes the PWM control of the hot wire 10.

  The operation in the defogger apparatus according to the third embodiment will be described below. FIG. 6 is a flowchart illustrating processing executed by the defogger apparatus according to the third embodiment.

  The ECU 1 determines whether or not the switch 3 is turned on (S40). If it is not turned on (S40: NO), the ECU 1 waits until it is turned on. When turned on (S40: YES), the ECU 1 causes the power feeding circuit 2 to start power feeding to the heat wire 10 (S41), starts a timer, and starts counting (S42). The ECU 1 obtains the current I and the voltage V detected by the current sensor 4 and the voltage sensor 5 (S43), and calculates the temperature rise ΔT by the above formula (1) or formula (2) (S44).

  The ECU 1 determines whether or not the calculated temperature rise ΔT is equal to or greater than a predetermined value Tth (S45). If it is equal to or greater than the predetermined value Tth (S45: YES), the ECU 1 determines whether or not a predetermined time has elapsed since the timer was started in S42 (S46). When the predetermined time has not elapsed (S46: NO), the ECU 1 starts PWM control of the hot wire 10 via the power feeding circuit 2 (S47). At this time, the ECU 1 calculates the voltage Vpwm described above. Then, ECU1 performs the process of S46, and performs PWM control of the hot wire 10 until predetermined time passes. When the predetermined time has elapsed (S46: YES), the ECU 1 causes the power feeding circuit 2 to stop power feeding (S48), and ends this processing.

  On the other hand, when the calculated temperature rise ΔT is not equal to or greater than the predetermined value Tth (S45: NO), the ECU 1 determines whether or not a predetermined time has elapsed since the timer was started in S42 (S49). When the predetermined time has not elapsed (S49: NO), the ECU 1 executes the process of S43. When the predetermined time has elapsed (S49: YES), the ECU 1 causes the power feeding circuit 2 to stop power feeding (S48), and ends this processing.

  As described above, in the third embodiment, the temperature increase degree ΔT is calculated without calculating the change amount ΔR of the resistance value of the hot wire 10 as in the first embodiment. Then, when the temperature rise ΔT is equal to or greater than the predetermined value Tth, PWM control of the hot wire 10 is performed. Thereby, after the fogging of the rear window 101 is removed, the rear window 101 can be prevented from being fogged again. In addition, power consumption can be reduced by intermittently supplying power to the hot wire 10.

(Embodiment 4)
Embodiment 4 according to the present invention will be described below. The calculation method of the temperature T of the hot wire 10 is different from that of the second embodiment. Further, the fourth embodiment is different from the second embodiment in that when the temperature T is equal to or higher than a predetermined temperature, the hot wire 10 is subjected to PWM control. Hereinafter, differences from the second embodiment will be described.

  The configuration of the defogger apparatus according to the fourth embodiment and the method for calculating the temperature rise ΔT are the same as those in the second embodiment. The ECU 1 calculates the temperature T of the hot wire 10 at the resistance value R of the hot wire 10 that has changed due to the temperature rise. The temperature T is calculated by T = ΔT + Ta. Ta is the ambient temperature and is calculated by Ta = (Tin + Tout) / 2. Note that the voltage Vpwm in the PWM control is calculated by the same method as in the third embodiment.

  The ECU 1 turns off the defogger device when the calculated temperature T of the hot wire 10 is equal to or higher than the vehicle interior temperature Tin and the vehicle exterior temperature Tout detected by the vehicle interior temperature sensor 6 and the vehicle exterior temperature sensor 7. That is, the ECU 1 causes the power supply circuit 2 to stop supplying power to the heat wire 10.

  The operation of the defogger apparatus according to the fourth embodiment will be described below. FIG. 7 is a flowchart illustrating processing executed by the defogger apparatus according to the fourth embodiment.

  The ECU 1 determines whether or not the switch 3 is turned on (S60). If it is not turned on (S60: NO), the ECU 1 waits until it is turned on. When turned on (S60: YES), the ECU 1 causes the power feeding circuit 2 to start power feeding to the heat wire 10 (S61), starts a timer, and starts counting (S62). Next, the ECU 1 acquires the current I and the voltage V detected by the current sensor 4 and the voltage sensor 5, and the vehicle interior temperature Tin and the vehicle exterior temperature Tout detected by the vehicle interior temperature sensor 6 and the vehicle exterior temperature sensor 7 (S63). The ECU 1 calculates the temperature rise ΔT by using the formula (1) or the formula (2) (S64).

  Next, the ECU 1 calculates the ambient temperature Ta based on the vehicle interior temperature Tin and the vehicle exterior temperature Tout (S65), and calculates the temperature T by adding the temperature rise ΔT and the ambient temperature Ta (S66). The ECU 1 determines whether or not the calculated temperature T is equal to or higher than the vehicle interior temperature Tin and the vehicle exterior temperature Tout (S67).

  When the temperature is equal to or higher than the vehicle interior temperature Tin and the vehicle exterior temperature Tout (S67: YES), the ECU 1 determines whether or not a predetermined time has elapsed since the timer was started in S62 (S68). When the predetermined time has not elapsed (S68: NO), the ECU 1 starts PWM control of the hot wire 10 via the power feeding circuit 2 (S69). At this time, the ECU 1 calculates the voltage Vpwm described above. Then, ECU1 performs the process of S68 and performs PWM control of the hot wire 10 until predetermined time passes. When the predetermined time has elapsed (S68: YES), the ECU 1 causes the power feeding circuit 2 to stop power feeding (S70), and ends this process.

  On the other hand, when the calculated temperature T is not equal to or higher than the vehicle interior temperature Tin and the vehicle exterior temperature Tout (S67: NO), the ECU 1 determines whether or not a predetermined time has elapsed since the timer was started in S62 (S71). When the predetermined time has not elapsed (S71: NO), the ECU 1 executes the process of S63. When the predetermined time has elapsed (S71: YES), the ECU 1 causes the power feeding circuit 2 to stop power feeding (S70), and ends this processing.

  As described above, in the fourth embodiment, the temperature T of the hot wire 10 is calculated, and the PWM control of the hot wire 10 is performed when the temperature T is equal to or higher than the vehicle interior temperature Tin and the vehicle exterior temperature Tout. Thereby, it is possible to prevent the power consumption from increasing by continuing to supply power even after the condensation of the rear window 101 is removed. Further, by intermittently supplying power, it is possible to prevent the temperature of the hot wire 10 from dropping and fogging of the rear window 101 from occurring again. In this case, by using intermittent power supply, power consumption can be suppressed in comparison with the case where power is constantly supplied to the hot wire 10 in order to prevent the rear window 101 from being clouded.

  The preferred embodiments of the present invention have been specifically described above, but each configuration, operation, and the like can be appropriately changed and are not limited to the above-described embodiments. In the above-described embodiment, the control device according to the present invention is described as a defogger device. However, the control device according to the present invention may be mounted on another in-vehicle device. For example, the operation of the ECU 1 of the defogger apparatus described above may be executed by an ECU of an air conditioner or the like to control power supply to the heat wire 10. Moreover, the method of calculating the temperature of the heat wire 10 or the temperature rise degree based on the current and voltage flowing through the heat wire 10 is not limited to the above-described embodiment.

1 ECU
2 Power supply circuit 3 Switch 4 Current sensor 5 Voltage sensor 10 Heating wire 101 Rear window

Claims (4)

In the control device that controls the power supply to the heating wire arranged in the car window,
Means for detecting current and voltage flowing through the heating wire when energized;
Calculation means for calculating a temperature related to the heating wire based on the detected current and voltage;
A control device comprising: stop means for stopping power supply to the heating wire based on the calculated temperature. The current and voltage flowing through the heating wire are calculated over time,
Based on the detected current and voltage, means for calculating the resistance value of the heating wire over time;
Means for calculating the calculated change amount of the resistance value,
The calculating means includes
Based on the calculated change amount of the resistance value, calculate the temperature difference at the time of calculating the resistance value related to the change amount,
2. The control device according to claim 1, wherein when the calculated temperature difference is equal to or greater than a predetermined value, the stopping unit stops power feeding. 3. Means for calculating a resistance value of the heating wire based on the detected current and voltage;
Means for obtaining the temperature inside and outside the vehicle,
The calculating means includes
Based on the calculated resistance value of the heating wire, calculate the temperature of the heating wire,
The stopping means is
2. The control device according to claim 1, wherein power supply is stopped when the calculated temperature of the heating wire is equal to or higher than the acquired in-vehicle temperature and out-of-vehicle temperature. Means for measuring the elapsed time after the start of power supply to the heating wire,
The stopping means is
When a predetermined time has elapsed since the start of power supply, the power supply is stopped.
When the temperature difference is equal to or higher than a predetermined value, or when the temperature of the heating wire is equal to or higher than the vehicle interior temperature and temperature, further includes means for intermittently supplying power to the heating wire until a predetermined time has elapsed since the start of power supply. The control device according to claim 2 or 3, wherein

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