JP2006151199A - Electric heater and vehicular air-conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce troubles caused by instantaneous generation of rush current running in a conductive heat generation row 23. <P>SOLUTION: The electric heater is constituted by laminating at least a conductive heat generation element row 23 and a heat exchange fin part 22. A circuit to conduct the conductive heat generation element row 23 includes a first circuit 33a to connect a DC resistor 33 in series, a second circuit 33b not via the DC resistor 33, and a relay device 34 to change the first and second circuits 33a, 33b. When conducting the conductive heat generation element row 23, conduction is started from the first circuit 33a side, and then, switched to the second circuit 33b side. Only during the generation of the rush current, the DC resistor 33 is connected in series to the conductive circuit, the resistance of the DC resistor 33 is added to the resistance of the conductive heat generation element row 23, and the rush current is suppressed accordingly. Troubles caused by instantaneous generation of the rush current conducted to the conductive heat generation element row 23 can be reduced thereby. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric heater configured by laminating at least an energizing heat generating portion and a heat exchange member, and a vehicle air conditioner using the same, and is used as an auxiliary heat source at the start of heating in the vehicle air conditioner. Is preferred.

As one form of the electric heater, a structure in which a heat dissipating fin, an energizing heat generating element array, and an electrode plate are stacked in several layers as shown in Patent Document 1 is well known. In addition, the present applicant has patented a device in which such an electric heater is used as an auxiliary heat source for heating of a vehicle air conditioner, and the energization heating element array is gradually energized at the start of heating in order to reduce the maximum power consumption. It is disclosed in Document 2. In general, a positive temperature coefficient thermistor (PTC element) is used as an energization heating element of such an electric heater.
JP-A-7-19781 JP-A-5-169967

  FIG. 6 is a schematic configuration diagram of a heat exchange core portion of a conventional PTC heater 20, and FIG. 7 is a schematic circuit diagram of the PTC heater 20 of FIG. As shown in FIGS. 6 and 7, the heat exchange fin structure 22, the energization heating element array 23, and the electrode plate 24 are sequentially stacked, and when the energization heating element array 23 becomes three or more, the two element arrays 23 are obtained. A common electrode 24C to be energized is generated. In FIG. 7, reference numeral 31 denotes a fuse, and 32 denotes an energization switch. In addition, since these symbols correspond to the symbols in the embodiments described later, the description here is omitted.

  FIG. 8 is a graph showing that a plurality of element rows 23 are energized in stages, and FIG. 4 is a graph showing current transition immediately after the start of heating in the conventional and the present invention. And as shown in the said patent document 2, when energizing to the element row | line 23 gradually in order to reduce maximum power consumption at the time of heating start, if the common electrode 24C enters, the two element row | line | columns 23 will be in an energized state at once (FIG. 8), a large inrush current is generated (refer to the prior art in FIG. 4), and the voltage drop is instantaneously increased, resulting in problems such as flickering of the headlight.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide an electric heater and a vehicle that can alleviate problems caused by inrush current generation at the moment when the energization heating element array is energized. It is to provide an air conditioner.

  In order to achieve the above object, the present invention employs technical means described in claims 1 to 5. That is, according to the first aspect of the present invention, the electric heater is configured by laminating at least the energization heat generating portion (23) and the heat exchange member (22), and the circuit for energizing the energization heat generating portion (23) is connected to the direct current. Circuit switching for switching the first circuit (33a) connecting the resistance means (33) in series, the second circuit (33b) not passing through the DC resistance means (33), and the first and second circuits (33a, 33b) When means (34) is provided to energize the energization heat generating part (23), energization is started from the first circuit (33a) side, and then the second circuit (33b) side is switched.

  This is because the DC resistance means (33) is connected in series to the energization circuit only during the generation of the inrush current, and the resistance of the DC resistance means (33) is added to the resistance of the energization heat generating section (23), and the inrush is made accordingly. The current is suppressed (see the present invention in FIG. 4). According to the first aspect of the present invention, it is possible to reduce a problem caused by the occurrence of an inrush current at the moment when the energization heat generating portion (23) is energized.

  According to a second aspect of the present invention, the electric heater according to the first aspect further comprises connection control means (35) for controlling the operation of the circuit switching means (34), and the connection control means (35) is energized. The circuit switching means (34) is controlled to switch from the first circuit (33a) side to the second circuit (33b) side after a predetermined time (T) from the start of energization to the heat generating part (23). It is said.

  According to the second aspect of the present invention, if the DC resistance means (33) remains connected, the output is reduced by a loss corresponding to the DC resistance means (33). Therefore, the circuit switching means (34) is used. Then, after a predetermined time (T) of about several seconds from the start of energization, the output is switched to the second circuit (33b) side not via the DC resistance means (33) to prevent a decrease in output (see the present invention in FIG. 4). .

  In the invention according to claim 3, in the electric heater according to claim 1 or 2, there are three or more rows of energized heat generating portions (23), and a plurality of energized heat generating portions (23 ), The DC resistance means (33) and the circuit switching means (34) are connected to a common electrode (24C) connected to a plurality of energization heat generating parts (23). Yes.

  This is because when the common electrode (24C) is energized, a current twice as large as that of the other stage is generated as shown in FIG. According to the third aspect of the present invention, it is possible to eliminate the protrusion of the load applied to the power supply side per stage, thereby eliminating the occurrence of a large voltage drop.

  The invention according to claim 4 is characterized in that in the electric heater according to any one of claims 1 to 3, a relay device (34) is used as the circuit switching means (34). According to the fourth aspect of the present invention, it is possible to reduce the cost by configuring the mechanical relay device (34).

  Moreover, in invention of Claim 5, the electric heater (20) in any one of Claim 1 thru | or 4 is provided as an auxiliary heater, and it supplies with electricity to the electricity_generation heat | fever part (23) at the time of a heating start. It is said. According to the fifth aspect of the present invention, it is possible to reduce problems caused by an instantaneous voltage drop, such as a headlight flickering at the start of heating. Incidentally, the reference numerals in parentheses of the above means are examples showing the correspondence with the specific means described in the embodiments described later.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of a vehicle air conditioner 1 according to an embodiment of the present invention. This is a vehicle air conditioner (car) as an auxiliary heating heat source that is effective immediately at the start of heating in hybrid vehicles, diesel vehicles, gasoline vehicles, etc. An air conditioner) 1 incorporates an electric heater (hereinafter referred to as a PTC heater) 20.

  An air introduction port 6 that communicates with the outside air introduction port 4 or the inside air introduction port 5 by switching the inside / outside air switching door 3 is provided at one end of the air conditioning case 2 that forms the outer shell of the vehicle air conditioner 1. 6, a blower fan 8 such as a centrifugal multiblade fan driven by a blower motor 7 is disposed. Inside the air conditioning case 2, in addition to the blower fan 8, toward the downstream side of the air flow, an evaporator 9 that exchanges heat with air to cool air, and a heater core 10 of a hot water heater that exchanges cold air with warm air Are arranged sequentially.

  Further, on the upstream side of the heater core 10, an air mix door 11 is provided for switching whether the cool air that has passed through the evaporator 9 is blown to the heater core 10 or blown to the air mix unit M described later. The PTC heater (auxiliary heater) 20 of the present embodiment is arranged downstream of the heater core 10 in the air conditioning case 2 so as to be arranged in parallel with the heater core 10, and the air blown from the upstream side of the heater core 10 is blown out. Air can be blown to the downstream side of the PTC heater 20.

  An air mixing unit M is formed on the downstream side of the PTC heater 20 to mix cold air and hot air so as to obtain an appropriate temperature. A defroster blower is provided at the other end of the air conditioning case 2 on the downstream side. An outlet 12, a face outlet 13, and a foot outlet 14 are formed. A defroster door 15 is disposed at the defroster air outlet 12, a face door 16 is disposed at the face air outlet 13, and a foot door 17 is disposed at the foot air outlet 14.

  2A is a perspective view showing a schematic configuration of the PTC heater 20, and FIG. 2B is a partial perspective view of a heat exchange core portion. The PTC heater 20 forms a heat exchange core portion by sequentially laminating an energization heating element array 23 as an energization heat generation portion, a heat exchange fin structure 22 as a heat exchange member, and an electrode plate 24 as an electrode member. In order to make good contact between the laminated members, the frame 26 having a spring portion (not shown) is pressed from both ends in the lamination direction, and the housing 26 is viewed from a direction orthogonal to the lamination direction (substantially left-right direction in FIG. 2). It is held by fitting.

  As shown in FIG. 2B, the energization heating element array 23 has a plurality of PTC elements 23a fitted in a resin frame 23b formed of a heat-resistant resin material (for example, 66 nylon, polybutadiene terephthalate, etc.). It is composed. In addition, the heat exchange fin structure 22 maintains a contact area between the corrugated fin 22a obtained by forming a thin aluminum plate into a corrugated shape, and the fin 22a in a certain shape, and with the PTC element 23a and the electrode plate 24. The aluminum plate 22b is brazed and joined.

  The housing 26 is a resin housing formed of the same resin material as that of the resin frame 23b, and the one end side housing 26B only holds the heat exchange core portion, but the other end side housing 26A is an electrode plate. A terminal portion provided in 24 penetrates to form a connector portion C on the outer surface side.

  Next, the configuration of the main part of the present invention will be described. FIG. 3 is a schematic circuit diagram of the PTC heater 20 to which the present invention is applied. Here, as an example, a description will be given assuming that there are four energized heating element rows 23. Then, a first circuit 33a in which a DC resistor 33 as a DC resistor means is connected in series to the energizing circuit of the common electrode 24C that is in contact with the plurality of energizing heating element rows 23, and a second circuit that does not go through the DC resistor 33. And a relay device 34 as circuit switching means for switching between the first and second circuits 33a and 33b.

  The relay device 34 is controlled by a control amplifier 35 as connection control means together with the energization switch 32. The control amplifier 35 energizes the energized heat generating element array 23 in accordance with an operation command from the air conditioning control device 36. Incidentally, reference numeral 31 in FIG. 3 denotes a fuse for protecting from overcurrent.

  In such a configuration, in the present embodiment, when the energization circuit of the common electrode 24C is energized, the control amplifier 35 starts energization from the first circuit 33a side including the DC resistor 33, and after a predetermined time T from the energization start. The relay device 34 is controlled so as to switch to the second circuit 33b side where the DC resistance 33 does not enter.

  Next, features and effects of this embodiment will be described. The first circuit 33a is a first circuit 33a in which a direct current resistor 33 is connected in series to a circuit that energizes the energized heat generating element array 23. And a second circuit 33b that does not pass through the DC resistor 33 and a relay device 34 that switches between the first and second circuits 33a and 33b. When energizing the energization heating element array 23, energization is performed from the first circuit 33a side. It is started and then switched to the second circuit 33b side.

  This is because the direct current resistor 33 is connected in series to the energization circuit only during the generation of the inrush current, and the resistance component of the direct current resistor 33 is added to the resistance component of the energization heating element array 23, thereby suppressing the inrush current. (See the present invention in FIG. 4). According to this, it is possible to reduce problems caused by inrush current generation at the moment when the energization heating element array 23 is energized.

  In addition, a control amplifier 35 that controls the operation of the relay device 34 is provided, and the control amplifier 35 starts from the energization of the energization heat generating element array 23, and after a predetermined time T, the first circuit 33a side to the second circuit 33b. The relay device 34 is controlled to switch to the side. According to this, since the output is reduced due to the loss of the DC resistor 33 with the DC resistor 33 connected, the DC resistor 33 is connected after a predetermined time T of about several seconds from the start of energization using the relay device 34. The output is reduced by switching to the second circuit 33b that is not interposed (see the present invention in FIG. 4).

  In addition, in the electric heater in which there are three or more energized heat generating element rows 23 and gradually energizes the plurality of energized heat generating element rows 23 at the start of heating, the DC resistor 33 and the relay device 34 are connected to the plurality of energized heat generating element rows 23. It is connected to the connected common electrode 24C. This is because when the common electrode 24C is energized, a current twice as large as that of the other stage is generated as shown in FIG. According to this, since the thing which protruded with the load given to the power supply side per stage can be eliminated, generation of a large voltage drop can be eliminated.

  A relay device 34 is used as the circuit switching means 34. According to this, the cost can be suppressed by configuring with the mechanical relay device 34. Further, the PTC heater 20 described above is provided as an auxiliary heater, and the energized heat generating element array 23 is energized at the start of heating. According to this, it is possible to reduce problems due to an instantaneous voltage drop, such as a headlight flickering at the start of heating.

(Other embodiments)
The present invention is not limited to the embodiment described above. First, FIG. 5 is a schematic circuit diagram of a PTC heater 20 according to another embodiment of the present invention. In the above-described embodiment (the circuit diagram of FIG. 3), the connection direction with respect to the plus side and the minus side on the circuit is reversed, the energizing switch 32 on the minus electrode side, and the DC resistor 33 on the minus side of the common electrode 24C. Although the relay device 34 is configured, such a circuit configuration may be used.

  In the above-described embodiment, in the vehicle air conditioner 1, the PTC heater 20 is arranged so as to be juxtaposed with the heater core 10, but is arranged in a foot duct (not shown) that distributes air to the foot outlet. Also good. Further, the PTC heater 20 of the present invention may be one in which the energized heating element array 23 is incorporated in a part of a heat exchange core part such as a hot water heat exchanger (heater core). Moreover, the electrode plate 24 may not necessarily be laminated, but may be a simplified configuration using the aluminum plate 22b of the heat exchange fin structure 22 as an electrode plate.

  In addition to the relay device 34, the circuit switching means may be, for example, an electronic element such as a power transistor. Further, the PTC heater is not limited to the PTC heater that gradually energizes the plurality of energization heating element rows 23, but may be a PTC heater that energizes the plurality of energization heating element rows 23 at a time, and the common electrode 24C that is particularly effective. However, the present invention may be applied to a single electrode.

1 is a schematic configuration diagram of a vehicle air conditioner 1 according to an embodiment of the present invention. (A) is a perspective view which shows schematic structure of the PTC heater 20, (b) is a fragmentary perspective view of a heat exchange core part. It is a schematic circuit diagram of the PTC heater 20 to which this invention is applied. It is a graph showing the electric current transition immediately after the heating start in the past and this invention. It is a schematic circuit diagram of the PTC heater 20 in other embodiment of this invention. It is a heat exchange core part schematic block diagram of the conventional PTC heater 20. FIG. It is a schematic circuit diagram of the PTC heater 20 of FIG. It is a graph which shows energizing a plurality of element rows 23 in steps.

Explanation of symbols

20 ... PTC heater (electric heater)
22 ... Heat exchange fin structure (heat exchange member)
23 ... Electric heating element array (electric heating element)
24C ... Common electrode 33 ... DC resistance (DC resistance means)
33a ... 1st circuit 33b ... 2nd circuit 34 ... Relay device (circuit switching means)
35 ... Control amplifier (connection control means)
T ... predetermined time

Claims (5)

An electric heater configured by laminating at least an energization heat generating portion (23) and a heat exchange member (22);
A first circuit (33a) for connecting DC resistance means (33) in series to a circuit for energizing the energization heat generating section (23), and a second circuit (33b) not via the DC resistance means (33), Circuit switching means (34) for switching the first and second circuits (33a, 33b);
When energizing the energization heat generating part (23), the energization is started from the first circuit (33a) side, and then switched to the second circuit (33b) side. Connection control means (35) for controlling the operation of the circuit switching means (34),
The connection control means (35) switches from the first circuit (33a) side to the second circuit (33b) side after a predetermined time (T) from the start of energization to the energization heat generating part (23). The electric heater according to claim 1, wherein the circuit switching means (34) is controlled. In the electric heater in which the energization heat generation part (23) has three or more rows and gradually energizes the plurality of energization heat generation parts (23) at the start of heating,
The DC resistance means (33) and the circuit switching means (34) are connected to a common electrode (24C) connected to a plurality of the energization heat generating parts (23). An electric heater according to any one of the above.   The electric heater according to any one of claims 1 to 3, wherein a relay device (34) is used as the circuit switching means (34).   An air conditioner for vehicles, comprising the electric heater (20) according to any one of claims 1 to 4 as an auxiliary heater and energizing the energization heat generating part (23) at the start of heating.

Images