JPH11241832A - Combustion heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow hot water temperature simply to be targeted temperature linearly by using a simple combustion heater. SOLUTION: It is assumed that TWO becomes 80 deg.C (2) from the case of 70 deg.C of water temperature TW and 70 deg.C of TWO (1) by operation of a temperature-controlling lever. Then in the case of (1) each scale of a horizontal axis is as shown in the figure. Because water temperature TW is 70 deg.C, a heating operation mode is a L0 heating operation mode. And immediately after a change to the case of (2), the water temperature TW still remains 70 deg.C, then when TWO becomes 80 deg.C the heating operation mode is changed to a Hi heating operation mode, thereby, according to TWO, in relation to setting a map of the figure, changing TW to TWO degree to allow the water temperature TW to rise to TWO (80 deg.C).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion type heating apparatus using a combustion type heater, and is particularly useful when applied to an air conditioner for an electric vehicle.

[0002]

2. Description of the Related Art Conventionally, a combustion type heater used in a generally popular combustion type heating device is of a two-stage switching type, and specifically, a HIGH operation mode in which a large amount of fuel is supplied.
And a LOW operation mode in which the fuel supply amount is small. And, the above-mentioned combustion type heater, the above-mentioned HIGH
It is known that the actual hot water temperature is controlled to a substantially constant temperature (for example, 80 ° C.) by switching between the operation mode and the LOW operation mode. Specifically, the water temperature is controlled to approximately 80 ° C. by varying the combustion capacity according to a detection value TW of a water temperature sensor that detects the temperature of the hot water as shown in a map shown in FIG.

[0003]

However, when such a combustion type heater is mounted on an electric vehicle in which a heating heat source cannot always obtain high-temperature engine cooling water as in a normal vehicle, for example, the hot water temperature is reduced. It is not advisable to always maintain the temperature around 80 ° C. That is, when the temperature of the hot water is not so necessary, that is, when the heating load is small, the heating load such as 80 ° C. is not required, and the heating load can be covered with a lower hot water temperature. For this reason, if the hot water temperature can be changed according to the heating load, energy can be saved. Therefore, the use of a combustion type heater that can change the combustion capacity linearly is considered. However, in order to make such a combustion type heater practical, the combustion capacity (fuel supply amount, combustion air Since it is necessary to precisely control the amount of supply, the structure and control are complicated, and there is a problem of an increase in cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a combustion type heating apparatus which can easily use a simple combustion type heater to linearly set the hot water temperature to a target temperature.

[0005]

According to the present invention, in order to achieve the above object, according to the first aspect of the present invention, there is provided a target temperature calculating means (S3) for calculating a target temperature (TWO) of the temperature of hot water.
00) and changing means (S400) for changing the predetermined relationship based on the target temperature (TWO) such that the hot water temperature (TW) becomes the target temperature (TWO).

[0006] Thus, the fuel supply amount,
That is, the predetermined relationship at which the combustion capacity is switched is changed based on the target temperature such that the hot water temperature becomes the target temperature. Therefore, the temperature of the hot water can be easily and linearly set to the target temperature by using a simple combustion type heater. Further, a specific configuration is as described in claim 2.
Can be set at least in a first heating mode (Lo) in which the fuel supply amount is a first predetermined amount and in a second heating mode (Hi) in which the fuel supply amount is a second predetermined amount larger than the first predetermined amount. The predetermined relationship is that when the hot water temperature (TW) becomes higher than a predetermined target temperature in the second heating mode, the mode is switched to the first heating mode, and the hot water temperature (TW) becomes higher than the predetermined target temperature in the first heating mode. When the temperature is lowered, the mode is switched to the second heating mode, and the changing means (S4
00) is characterized in that the higher the target temperature (TWO), the higher the predetermined target temperature, and the lower the target temperature (TWO), the lower the predetermined target temperature.

According to this, when the target temperature increases, the predetermined target temperature increases accordingly, so that the heating mode is easily switched to the second heating mode having a high combustion capacity. On the other hand, when the target temperature decreases, the predetermined target temperature decreases accordingly, so that the heating mode is easily switched to the first heating mode having a low combustion capacity. By doing so, the same effect as that of the first aspect can be obtained.

[0008] The reference numerals in parentheses of the above means indicate the correspondence with the specific means described in the embodiment described later.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. This example is an example in which the vehicle air conditioner of the present invention is applied to an electric vehicle without an engine.
FIG. 1 shows a system diagram of a vehicle air conditioner. The vehicle air conditioner 1 has an air conditioning case 2 that forms an air flow path into a vehicle interior. The air upstream side of the air-conditioning case 2 is an inside / outside air blowing unit 3.
A centrifugal fan 4 for generating an airflow toward the vehicle compartment is accommodated in the air conditioning case 2. The inside / outside air blowing unit 3 is formed with an inside air inlet and an outside air inlet (not shown), and these inlets are selectively opened and closed by an inside / outside air switching door (not shown).

The inside and outside air blowing unit 3 of the air conditioning case 2
An evaporator 5 which is a cooling heat exchanger for cooling the passing air is disposed downstream of the evaporator 5. The evaporator 5 is a component of a well-known refrigeration cycle 6 (refrigerant circuit). The refrigeration cycle 6 is a well-known one including a compressor, a condenser, a receiver, an expansion valve, and the evaporator 5. Also, the compressor is
In this example, the rotation speed is variably controlled in accordance with the cooling load by being driven by an electric motor (not shown).

A heater core 7, which is a heating heat exchanger for heating the passing air, is arranged downstream of the evaporator 5 in the air conditioning case 2. In the figure, reference numeral 8 denotes a door for closing and opening both ventilation surfaces of the heater core 7.
The door 8 is driven and controlled by a servo motor (not shown), and is controlled to a position indicated by a chain line in the figure when the cooling operation mode is set by an occupant. As a result, in the cooling operation mode, air does not pass through the heater core 7. On the other hand, when the heating operation mode is set by the occupant, the heating operation mode is controlled to the position indicated by the solid line in the figure. Thereby, in the heating operation mode, all the air flowing in the air conditioning case 2 passes through the heater core 7.

Further, a plurality of air passages (not shown) corresponding to a plurality of air outlets arranged in the vehicle interior are formed on the downstream side of the heater core 7 in the air. It is opened and closed by the switching door. Thereby, the well-known blowing mode is switched. In addition,
The outlet mode switching door is also driven by a servomotor.

The heater core 7 heats air using hot water as a heat source. For this reason, the heater core 7 is installed in a hot water circuit 9 in which hot water circulates. The hot water circuit 9 includes an electric water pump (WP) that is a source of hot water circulation.
10 are provided. Further, the hot water circuit 9 is provided with a combustion type heater 11 for heating hot water by burning fuel. The combustion type heater 11 is a well-known type, and includes a fuel pump (not shown), a blower for supplying combustion air, and the like. The combustion type heater 11 of the present embodiment has a Lo heating mode (first heating mode) in which the fuel supply amount by the combustion pump is set to the first predetermined amount and the air supply amount of the blower is set to the first predetermined air amount. A Hi heating mode (second heating mode) in which the fuel supply amount is a second predetermined amount larger than the first predetermined amount, and the air supply amount is a second predetermined air amount larger than the first predetermined air amount. Can be operated.

The hot water circuit 8 is provided with a temperature sensor 12 (temperature detecting means) for detecting the temperature of hot water circulating through the heater core 7. The temperature sensor 12 is configured by a temperature resistance element such as a thermistor. Next, a control system according to the present embodiment will be described with reference to FIGS. In FIG. 2, reference numeral 13 denotes an A / C.
ECU. The ECU 13 is a component of the control device 15 including a RAM and a ROM (not shown) as shown in FIG. 2, and various air conditioning control signals are input into the ECU 13. Specifically, the temperature sensor 12 and the post-evaporation temperature sensor 14 that is disposed immediately downstream of the evaporator 5 in the air and detects the air temperature immediately after passing through the evaporator 5 are connected to the control device 15.

An air-conditioning operation panel 16 arranged on an instrument panel in the vehicle compartment is connected to the control device 15 through an input. The air-conditioning operation panel 16 includes a cooling switch 17 that activates the refrigeration cycle to set the air-conditioning mode to the cooling operation mode, a heating switch 18 that activates the combustion type heater 11 to set the air-conditioning mode to the heating operation mode, A temperature adjusting lever 19 for adjusting the temperature of the conditioned air is provided. Although not shown, the air conditioning operation panel 16 is provided with an air volume adjustment lever for adjusting the air volume of the conditioned air from the centrifugal fan 4, and an inside / outside air switching switch for switching between inside and outside air modes.

A combustion heater controller 20 for controlling the combustion heater 11 is connected to the control device 15 as shown in FIG. The heater control 20 in this example is configured by an analog circuit, and is a control device for switching the heating mode between the Lo heating mode and the Hi heating mode. Next, the contents of control processing in the control device 15 will be described. First, when the cooling switch 17 is turned on and the cooling operation mode is started, the control device 15 calculates a target air-conditioning air blowing temperature TAO (C) during cooling based on an operation position of the temperature adjustment lever 19 and the like. , The temperature detected by the post-evaporation temperature sensor 14 is
The number of revolutions of the compressor is controlled so as to satisfy (C).

On the other hand, when the heating switch 18 is turned on, a heating operation mode is started. FIG. 3 is a flowchart of the control process during heating. First,
In step S100, the detection value TW of the temperature sensor 12 and the detection value Te of the post-evaporation temperature sensor 14 are read and stored as sensor value inputs. Step S10
At 0, the operation position of the temperature adjustment lever 19 is read and stored.

Next, in step S200, a target outlet temperature TAO (H) during heating is calculated based on the signal read in step S100. Subsequently, in step S300, the target hot water temperature TWO of the hot water supplied to the heater core 7 is calculated from the following equation (1).

[0019]

TWO = (TAO (H) -Te) / φ + Te where φ is the temperature efficiency of the air passing through the heater core, and the temperature efficiency is the numerator of the temperature of the air before and after passing through the heater core 7. The difference between the temperature of the hot water flowing into the heater core 7 and the temperature of the air before passing through the heater core 7 can be expressed as a denominator. Further, the denominator decreases as the amount of air passing through the heater core 7 increases. From such a concept, in this example, the temperature efficiency φ is determined from the map shown in FIG.

Next, in step S400, the operation mode of the combustion type heater 11 is determined. Specifically, in this example, the map shown in FIG. 3 is stored in the ROM, and the horizontal axis is the water temperature TW and the vertical axis is TW '(heating operation mode). That is, in this example, the water temperature TW and the preset heating operation mode are set in a predetermined relationship.
For example, the predetermined relationship is such that the thresholds a to d at which the heating operation mode is switched are determined by the water temperature Tw in the Hi heating operation mode as shown in FIG. When the temperature becomes higher than -2 (predetermined target temperature), the mode is switched to the Lo heating mode. FIG.
In the Lo heating operation mode, when the water temperature TW becomes lower than the threshold value TWO-2 (predetermined target temperature), H
Switch to i-heating mode. This step S40
Details of 0 will be described later.

In step S500, step S400
Is output to the heater controller 20 so as to be in the heating operation mode.
Control 1 Specifically, the heater controller 20 recognizes the signal TW 'and outputs the signal TW' to Hi.
, The combustion type heater 11 is set to the Hi heating operation mode, if Lo, the combustion type heater 11 is set to the Lo heating operation mode, and if OFF, the fuel supply amount of the combustion type heater 11 is set to 0 and combustion is performed. Stop.

Here, the output of the signal TW 'to the heater controller 20 is performed by the configuration shown in FIG. In the figure, reference numeral 21 denotes a multiplexer as an electronic switch. The multiplexer 21 receives the digital signal (TWO, TW ') in the map of step S400 as an input signal, and the heater controller 20 corresponding to the input signal.
Is converted into an analog signal for drive control. For this reason, as shown in FIG. 5, the multiplexer 21 is adjusted by the resistors R1 to R3 so that the output is converted into an analog signal applied to the heater controller 20.

Next, the contents of the control processing in step S400 will be described. As shown in FIG. 3, in this example, the threshold value at which the heating mode is switched uses the above-mentioned TWO, so that the scale of the map shown in FIG. 3 is changed. Therefore, even if the actual hot water temperature TW is the same, the heating operation mode differs depending on the target hot water temperature TWO. For example,
It is assumed that the water temperature TW is 70 ° C. and the TWO is 70 ° C., and then the temperature adjusting lever 19 is operated to bring the TWO to 80 ° C. Then, each scale on the horizontal axis is shown in FIG.
Since the water temperature TW is now 70 ° C., the heating operation mode is the Lo heating operation mode. Then, immediately after the water temperature TW is still 70 ° C., when TWO becomes 80 ° C., the heating operation mode becomes H
The mode is switched to the i-heating operation mode. That is, by changing the setting relation of the maps of FIGS. 3 and 6 according to TWO so that TW becomes the TWO degree, the water temperature TW increases and TWO increases.
(80 ° C.). Note that, as described above, TW
In order to change the above setting relation according to O so that TW becomes the TWO degree, an experiment may be performed to determine the scale of the horizontal axis.

That is, in this example, as is apparent from FIGS. 3 and 6, the threshold value at which the heating operation mode is switched increases as the TWO increases, and the threshold value decreases as the TWO decreases. Be changed. By doing so, in this example, the two-stage switching type simple combustion type heater 1 is used.
By using 1, the hot water temperature can be easily and linearly set as the target temperature. As a result, the hot water temperature can be controlled in accordance with the heating load, so that energy saving can be achieved without using extra energy.

The concept of the maps in FIGS. 3 and 6 can be represented by a flowchart in FIG. The threshold value a in FIGS. 3 and 6 is changed to steps S630 and S680, and the threshold value b in FIGS.
610, the threshold value c in FIGS.
Correspond to steps S660 and S670 in FIGS.
The middle threshold value d corresponds to steps S640 and S650.

First, it is assumed that TW 'is Hi and TW is 8
It is assumed that TWO has become 60 ° C. from the state of 0 ° C. That is, a case where the hot water temperature is changed from 80 ° C. to 60 ° C. will be described. In step S600, it is determined whether the previous value of TW 'is OFF, Lo, or Hi. Here, since the previous TW 'is Hi, step S610 is executed.
To determine whether TWO-2 is lower than TW.
Then, when the process proceeds to step S610 for the first time, the TW is still 80 ° C., so the determination result here is YES
Then, the process proceeds to step S620, where Tw 'is changed to Lo. For this reason, the hot water heating capacity of the combustion type heater 11 decreases, and the hot water temperature decreases.

Then, when the process proceeds to step S600,
Since TW 'was Lo last time, the process proceeds to step S630 according to the determination result here. Step S630
Then, it is determined whether TWO-5 is higher than TW.
Here, if the TW is too low and is, for example, 55 ° C., YES is determined in the step S630, TW ′ becomes Hi in the step S680, the combustion capacity of the combustion type heater 11 is increased, and the water temperature is reduced. Raise quickly.
Thereby, TW approaches TWO. On the other hand, if the TW is still 70 ° C. when the process proceeds to step S630, the determination in step S630 is NO, and the process proceeds to step S640. In step S640, TWO + 5 is T
It is determined whether it is lower than W. Here, since TW is 70 ° C., it is determined as YES, and the process proceeds to step S650, where TW ′ is turned off. Therefore, the combustion type heater 1
1, the heating water heating capacity further decreases, and the TW further decreases.

At the point when the process proceeds to step S640,
If the TW is 76 ° C., N is determined in step S640.
It is determined as O, and TW 'remains Lo. Next, when the process proceeds to step S600, since TW 'was OFF last time, the process proceeds to step S660 according to the determination result here. In step S660, it is determined whether TWO + 2 is higher than TW.

If TW is 70 ° C., NO is determined in step S660, so that TW ′ is
With FF, TW further decreases and TWO (60 ° C)
Approach. On the other hand, if the TW is 55 ° C., the water temperature is too low, and the result of the determination in step S660 is YES, the process proceeds to step S670, where TW ′ is set to Lo.
Then, the hot water is heated again by the combustion type heater 11. Thus, the combustion type heater 1 is set so that TW becomes TWO.
1 is controlled.

(Modification) In the above embodiment, the refrigeration cycle 6 uses only cooling. However, for example, a heat pump cycle for heating by switching the flow of the refrigerant may be used. In the case of a heat pump cycle, two indoor heat exchangers may be provided so that the dehumidifying operation can be performed. Further, when heating is performed by an indoor heat exchanger as a heat pump cycle, a heating water-refrigerant heat exchanger may be provided, and the heating performance may be improved by giving hot water heat to the refrigerant.

In each of the above embodiments, the water temperature thresholds a to c are changed according to TWO in order to set the water temperature TW to the target hot water temperature TWO.
It has a plurality of maps of water temperatures TW and TW 'corresponding to O,
TW 'may be directly determined according to the WO.

[Brief description of the drawings]

FIG. 1 is a system diagram of a combustion-type heating device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a control system in the embodiment.

FIG. 3 is a flowchart showing control processing contents in the embodiment.

FIG. 4 is a diagram showing how to determine a temperature efficiency φ in the embodiment.

FIG. 5 is a diagram illustrating signal processing inside an ECU in the embodiment.

FIG. 6 is a diagram showing a relationship between a target hot water temperature TWO and a heating operation mode in the embodiment.

FIG. 7 is a flowchart showing how to determine a heating operation mode according to the target hot water temperature TWO in the embodiment.

FIG. 8 is a diagram showing how to determine a heating operation mode of a conventional combustion heater.

[Explanation of symbols]

7: heater core, 11: combustion type heater, 12: temperature sensor, 13: ECU.

Claims (2)

[Claims] A heating heat exchanger using hot water as a heat source (7).
A combustion heater (11) for heating the hot water by burning fuel with a variable fuel supply amount; and a temperature detecting means (12) for detecting a hot water temperature of the hot water. 12) Hot water temperature (TW) detected
And a plurality of fuel supply amounts set in advance in a predetermined relationship, which is applied to a combustion type heating apparatus, and a target temperature calculating means (S300) for calculating a target temperature (TWO) of the temperature of the hot water. And a changing means (S400) for changing the predetermined relationship based on the target temperature (TWO) so that the hot water temperature (TW) becomes the target temperature (TWO). apparatus. 2. The combustion type heater (11) includes a first heating mode (Lo) in which at least the fuel supply amount is a first predetermined amount, and a second heating mode (Lo) in which the fuel supply amount is larger than the first predetermined amount. A second heating mode (Hi) as a fixed amount can be set, and the predetermined relationship is that when the hot water temperature (TW) becomes higher than a predetermined target temperature in the second heating mode, the first heating mode is set. When the hot water temperature (TW) becomes lower than the predetermined target temperature in the first heating mode, the mode is switched to the second heating mode. The changing means (S400) changes the target temperature (TWO). )
The higher the predetermined target temperature,
The combustion type heating apparatus according to claim 1, wherein the lower the target temperature (TWO), the lower the predetermined target temperature.