JP2011105279A - Defogger control device for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a defogger control device for an automobile capable of efficiently eliminating and preventing mist. <P>SOLUTION: This defogger control device for an automobile includes: a duty driving circuit 15D formed by connecting a power source 11 and a switching section 12 in series to a heating coil type heater 10 provided in a window glass to switch at least two duty ratios by the hour and output it as a control signal to the switching section 12; a timer 15C for timing to switch the duty ratio relative to the duty driving circuit 15D; and a switching time determination section 15B for determining the duty ratio switching time based on each signal detected by an outside air temperature sensor 17 and an inside air temperature sensor 18. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an automotive defogger control device, and more particularly to an automotive defogger control device that ensures optimum sunny performance by performing temperature management and time management.

  In order to remove fogging such as window glass in the vehicle, a defogger control device is mounted on the vehicle. In the defogger control device, a hot wire heater is attached to the window glass, and an electric current is passed through the hot wire while being temporally controlled. Specifically, a hot wire heater is connected to a power supply via a relay, and a switch and a timer circuit are connected to both sides of the relay to constitute a defogger control device. When the switch is turned ON, the relay operates to supply electric energy from the power source to the hot wire heater, and at the same time, the timer circuit operates. When a predetermined time elapses, the relay is turned off by a signal from the timer circuit, and no current is supplied from the power source to the hot wire heater. In this defogger control device, a constant current flows through the hot wire heater for a timer time. Therefore, power consumption is large.

  Therefore, in Patent Document 1, it is mentioned that duty of the energization to the hot wire heater is controlled to quickly remove the fogging of the glass and prevent the glass from fogging again. The duty factor is set to 100% until the predetermined time, the duty factor is set to α% smaller than 100% from the first predetermined time to the second predetermined time, and the duty factor is set to α% after the second predetermined time. Β% is smaller than%.

  In addition to the above, as a defogger control device, a vehicle defogger control device (Patent Document 2) capable of controlling energization of a hot wire heater based on the dew condensation condition of glass, outside temperature, inside / outside temperature difference, vehicle speed, outside temperature and freezing temperature There is a vehicle defogger control device (Patent Document 3) that makes the energization time to the hot wire heater variable according to the relationship.

JP-A-5-155313 JP-A-5-193341 JP 2004-210153 A

  However, in the device disclosed in Patent Document 1, when the operation switch is turned on by the driver, the hot wire heater is energized for a certain period of time with a duty factor of 100%, and then is separated with a duty factor of α%. Energized for a certain period of time. Since the time of each duty factor is constant, the energization time chart for the hot wire heater is the same regardless of the weather condition or day and night. In this case, the consumption of the battery by the hot-wire heater is uniformly determined, so that not only energy is wasted but also consideration for global warming is not sufficient.

  Accordingly, an object of the present invention is to provide an automotive defogger control device that can efficiently remove and prevent fogging.

  In order to achieve the above object, the present invention is an automotive defogger control device in which a power source and a switching unit are connected in series to a hot wire heater provided on a window glass, and the duty ratio is switched over time. The duty drive circuit that outputs the control signal to the switching unit, the timer for measuring the duty ratio switching timing for the duty drive circuit, and the duty ratio switching time is determined from the detection signals from the outside air temperature sensor and the inside air temperature sensor And a switching time determination unit.

  According to the above configuration, the energization time of the hot wire heater can be variably determined according to the outside air temperature and the inside air temperature, and therefore the energization timing can be controlled according to the weather condition or day and night.

  In the above configuration, the switching time determining unit preferably determines the switching time of the duty ratio based on a detection signal from any one of a solar radiation sensor and a vehicle speed sensor in addition to the outside air temperature sensor and the inside air temperature sensor. .

  According to the above configuration, power consumption can be reduced corresponding to the environment where the user is placed.

  According to the present invention, it is possible to control the amount of time supplied to the hot wire heater and the amount of heat per certain period, thereby preventing fogging of the window glass and realizing an automotive defogger control device with low energy consumption. it can.

It is a functional block diagram of the defogger control device for vehicles concerning the embodiment of the present invention. It is a time chart of the drive signal which flows into a switching part from a duty drive circuit. It is a figure for demonstrating the parameter | index and judgment program which are stored in the switching time determination part shown in FIG. 1, (A) is the relationship between 1st continuation time t1 and temperature, (B) is 2nd continuation. The relationship between the time t2 and the temperature, (C) shows the relationship between the ratio t2 / t1 of the second duration t2 to the first duration t1 and the temperature. It is a flowchart which shows the main operation | movement of the defogger control apparatus for motor vehicles.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and extends to the scope described in the claims and the equivalent scope thereof. Needless to say.

  FIG. 1 is a functional block diagram of an automotive defogger control apparatus according to an embodiment of the present invention. The automobile defogger control device 1 according to the embodiment of the present invention controls the amount of current supplied to a hot wire heater 10 provided on a window glass of a vehicle. The hot wire heater 10 has a power source 11 and a switching unit 12 connected in series. The controller 15 controls the opening and closing of the switching unit 12 and adjusts the amount of heat generated according to the energization control of the hot wire heater 10. is there.

  The control unit 15 includes a duty drive circuit 15D including an external signal processing unit 15A, a switching time determination unit 15B, and a timer 15C. The control unit 15 includes a switch 16 that a user operates to start heating the hot wire heater, an outside air temperature sensor 17 attached to the vehicle body, an inside air temperature sensor 18 attached indoors, a solar radiation sensor 19, A vehicle speed sensor 20 and the like are connected.

  These sensors and control unit 15 constitute an air conditioner ECU (Electric Control Unit) and other ECUs together with the switching unit 12 and the hot-wire heater 10. Detection signals from various sensors other than those described above are input to the ECU.

  The configuration of the control unit 15 will be described in more detail. The external signal processing unit 15A extracts a signal to the control unit 15, samples it at a necessary timing, and outputs it to the switching time determination unit 15B. The duty drive circuit 15D controls the voltage to the switching unit 12, for example, the gate electrode of the transistor, by the output signal, that is, the control signal.

  FIG. 2 is a time chart of the voltage flowing from the duty drive circuit 15D to the switching unit 12. The horizontal axis represents time, and the vertical axis represents the magnitude of the voltage applied to the switching unit 12. In the duty drive circuit 15D, as shown in FIG. 2, during the time t1, the ratio (duty ratio) obtained by dividing the pulse width by the pulse period τ in the shorter period τ1 is set to α%, for example, 100%. Therefore, a voltage is continuously applied to the switching unit 12. Therefore, when the time t is 0 to t1, a current always flows through the hot wire heater 10 and is heated.

  In the duty drive circuit 15D, since the ratio of the pulse width divided by the period τ in the shorter period τ1 is set to β% during the time t2, the voltage is continuously applied to the switching unit 12. It is not applied discretely. Therefore, from time t1 to t1 + t2, current flows or flows through the hot wire heater 10, so heating and cooling are repeated.

  The timer 15C is a means for measuring the duty ratio switching timing in the duty drive circuit 15D. When a predetermined time t1 elapses after the switch 16 is turned on, the timer 15C notifies the duty drive circuit 15D of the elapse of time and changes the duty ratio from α% to β%, for example.

  The switching time determination unit 15B determines the duty ratio based on the detection data of the outside air temperature sensor 17, the inside air temperature sensor 18, the solar radiation sensor 19, and the vehicle speed sensor 20 input to the control unit 15 via the external signal processing unit 15A. It is a means for planning the switching timing.

  The switching time determination unit 15B sets the ratio between the time t1 and the time t2 illustrated in FIG. 2 based on the difference between the outside air temperature sensor 17 and the inside air temperature sensor 18, for example. Therefore, the switching time determination unit 15B stores an index for obtaining the ratio between the time t1 and the time t2 and the total time t between the time t1 and the time t2 based on the value of each sensor. Of course, the total time t may be always constant. The time does not need to be two types, t1 and t2, but may be three or more types.

  In addition to the above, the switching time determination unit 15B is based on the detection data of the solar radiation sensor 19 and the vehicle speed sensor 20 in addition to the outside air temperature sensor 17 and the inside air temperature sensor 18, and the determination stored in the switching time determination unit 15B. According to the program, not only the temperature difference between inside and outside, but also the ratio of time t1 to time t2 and the total time t, depending on whether it is daytime or nighttime, whether it is driving at high speed or low speed or stopping. Ask.

  FIG. 3 is a diagram for explaining an index and a determination program stored in the switching time determination unit 15B. (A) is a relationship between the first duration t1 and temperature, and (B) is a second duration. The relationship between the time t2 and the temperature, (C) shows the relationship between the ratio t2 / t1 of the second duration t2 to the first duration t1 and the temperature. The solid line in each figure indicates the case where the irradiance sensor 19 determines that the illuminance is greater than the specified value and is in the daytime, and the dotted line indicates the case where the irradiance sensor 19 determines that the illuminance is less than the specified value and the nighttime.

  The first duration t1 is set as follows according to the outside air temperature or the inside air temperature as shown in FIG. In the daytime, when the temperature is low (for example, −5 ° C. or lower), t1 = ta, and when the temperature is high (for example, 5 ° C. or higher), t1 = tb, and during that time, t1 is linear from ta to tb in proportion to the temperature. T1 is determined as a value that decreases as a result. At night, the temperature at which the first duration t1 is shifted from ta to tb is, for example, 0 ° C. to 10 ° C. as indicated by the dotted line in FIG.

  About 2nd continuation time t2, as shown in FIG.3 (B), it sets as follows according to outside temperature or inside temperature. In the daytime, t2 = tc when the temperature is low (for example, −5 ° C. or lower), and t2 = 0 when the temperature is high (for example, 15 ° C. or higher). As a value that increases at a constant rate so that t2 becomes td at a temperature of 0 ° C and t2 becomes zero at a temperature of 15 ° C when the temperature exceeds 0 ° C. To decide. At night, the substantially continuous waveform in which the second duration t2 is increased from tc to td and decreased to zero is in a range from 0 ° C. to 20 ° C. as indicated by a dotted line in FIG. To do.

  When the ratio t2 / t1 of the second duration t2 to the first duration t1 is set as described above, it is as shown in FIG. In the daytime, when the temperature is as low as −5 ° C. or less, the ratio of t2 / t1 is kept low and constant, and when the temperature is in the range of −5 ° C. to 15 ° C., the ratio of t2 / t1 is set higher and the temperature is 15 If it is higher than ° C., the ratio of t2 / t1 is made zero. T2 / t1 for the temperature range of -5 ° C to 15 ° C is such that the ratio of t2 / t1 increases linearly as the temperature rises below about 0 ° C, and around 0 ° C to 5 ° C. A constant value is set to a value that linearly decreases with increasing temperature from 5 ° C to 15 ° C.

  For example, according to the difference between the outside air temperature and the inside air temperature, the first duration time t1, the first duration t1, the temperature value of any one of the inside air temperature and the outside air temperature is used from the relationship shown in FIGS. 2 and the ratio t2 / t1 are determined.

  Since the data as shown in FIG. 3 is stored in the duration determination unit 15B, the first duration t1 and the second duration t2 can be set. The setting method of the first duration t1 and the second duration t2 by the index stored in the switching time determination unit 15B and the determination program is not limited to FIG. The relationship between temperature and time t1, t2 can be set according to the above. In addition, regarding the relationship shown in FIG. 3, the first duration t1 and the second duration t2 can be set not only by the degree of sunlight but also by parameters such as the vehicle speed and humidity.

  Next, a method for removing and preventing fogging by the heater 10 of the automobile defogger control device 1 will be described. FIG. 4 is a flowchart showing main operations of the automobile defogger control device 1. Under the condition that the switch 16 is ON (YES in STEP 1), the external signal processing unit 15A outputs the values of the outside air temperature sensor 17, the inside air temperature sensor 18, and the solar radiation sensor 19 to the switching time determination unit 15B. The switching time determination unit 15B determines the first duration t1 and the second duration t2. At this time, as described above, various indexes and determination programs stored in the switching time determination unit 15B are used (STEP 2).

  The switching time determination unit 15B sets the first duration t1 and the second duration t2 determined in STEP 2 in the timer 15C. Then, the duty drive circuit 15D sets the duty ratio to α% and outputs a drive signal to the switching unit 13 until the first duration t1 is reached by the timer 15C. In this state, a current flows through the hot wire heater 10 at a duty ratio α (STEP 3).

  When the first duration time t1 has elapsed (Yes in STEP 4), the duty drive circuit 15D sets the duty ratio to β% by the timer 15C until the second duration time t2 is reached, and sends a drive signal to the switching unit 13. Output. In this state, a current flows through the hot wire heater 10 at a duty ratio β (STEP 5).

  When the second duration t2 has elapsed, that is, when the time t1 + t2 has elapsed (YES in STEP 6), the timer 15C is turned OFF (STEP 7), and no voltage is applied from the duty drive circuit 15D. Therefore, no current flows through the hot wire heater 10.

  As described above, in the embodiment of the present invention, the average ratio of the current flowing through the hot wire heater is determined according to the outside air temperature, the inside air temperature, the solar radiation situation, and the vehicle speed, so that it depends on the environment in which it is placed. The hot wire heater control can be performed, and at the same time, the power supply is not wasted and used, and it contributes to power saving. Also in that respect, the defogger control device for automobiles in the present invention may be called a hot wire heater device for automobiles.

  In the above description, the surrounding environment information is obtained from the outside air temperature sensor, the inside air temperature sensor, the solar radiation sensor, and the vehicle speed sensor connected to the ECU, but in addition to that, the detection data of the humidity sensor in the vehicle compartment is also taken into account. Thus, the average current ratio passed through the hot wire heater can be made variable.

1: automotive defogger control device 10: hot wire heater 11: power supply 12: switching unit 15: control unit 15A: external signal processing unit 15B: switching time determination unit 15C: timer 15D: duty drive circuit 16: switch 17: outside air temperature Sensor 18: Inside air temperature sensor 19: Solar radiation sensor 20: Vehicle speed sensor

Claims (2)

An automotive defogger control device in which a power source and a switching unit are connected in series to a hot-wire heater provided on a window glass,
A duty drive circuit that switches at least two duty ratios in time and outputs the control signal to the switching unit;
A timer for measuring the duty ratio switching timing for the duty drive circuit;
A switching time determination unit for determining the switching time of the duty ratio from each detection signal by the outside air temperature sensor and the inside air temperature sensor;
A defogger control device for an automobile, comprising:   The switching time determination unit determines the switching time of the duty ratio based on a detection signal from any one of a solar radiation sensor and a vehicle speed sensor in addition to the outside air temperature sensor and the inside air temperature sensor. 1. A vehicle defogger control device according to 1.

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