JPH0443817B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses engine cooling water as a heat source, and if necessary, reheats the air with a reheating device and heats the air with a heating heat exchanger. Regarding air conditioning equipment.

[Conventional technology]

In a vehicle air conditioner that uses a reheating device to reheat engine cooling water, the reheating device includes a temperature switch, and when the temperature of the engine cooling water has not risen sufficiently, the temperature switch signal is activated. The reheating device is configured to be activated using the reheating device. Such a temperature switch is generally placed on the cooling water inlet side of the reheating device.

[Problem that the invention seeks to solve]

In conventional systems, when trying to use the air conditioner for heating when the engine cooling water is sufficiently high but the air conditioner is not being operated as a heating system, there is For some cold cooling water the temperature switch may be placed at the operating point and the reheating device may be activated for a short period of time.

Such a short operation of the reheating device not only is not very effective for heating purposes, but also has the disadvantage of weakening the durability of reheating devices that utilize special heat sources such as combustion of fuel.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a vehicle air conditioning control device that suppresses unnecessary operations of a reheating device.

[Means for solving problems]

In order to achieve such an object, the present invention provides an air conditioner including a heating heat exchanger that uses engine cooling water as a heat source, and an air blower whose air blowing capacity can be adjusted. a selection device for selecting introduction/cutoff of cooling water; a reheating device installed in a cooling water passage from the engine to the heat exchanger for reheating the engine cooling water; and for adjusting the temperature of the vehicle passenger compartment. a control device that operates the selection device and the reheating device; the control device operates the reheating device when the temperature of the cooling water from the engine is below a predetermined temperature; and when the temperature of the cooling water is above the predetermined temperature. A technique characterized in that it includes a temperature switch that does not activate the reheating device, and a means for activating the reheating device after the selection device is brought into the introduction state when the reheating device is activated. This method adopted the following methods.

When activating the reheating device, the means for activating the reheating device after bringing the selection device into the introduction state includes: 1
In one embodiment this is accomplished by a delay circuit.

In another embodiment, the signal generating device has a value corresponding to a heat load required for temperature regulation of the passenger compartment, and the magnitude of the generated signal exceeds a first value requesting a preset heating effect. This is achieved by the combination of a comparison device which activates the selection device when the selection device is activated, and a comparison device which activates the reheating device when the magnitude of the generated signal exceeds a second value requiring a greater heating effect. be done.

[Effect]

With this configuration, when the control device wants to cause the heating heat exchanger to exert a heating effect, it operates the reheating device after putting the selection device into the introduction state. For this reason, the engine cooling water tends to be introduced into the heat exchanger without being heated by the reheating device initially. For this reason, the cooling water that has accumulated in the cooling water passage from the engine to the reheating device is discharged, and new cooling water is introduced from the engine, so whether the temperature is below the predetermined temperature for operating the reheating device is checked. The relatively cold water accumulated in the cooling water passage temporarily prevents the reheating device from operating.

In an embodiment in which when the reheating device included in the control device is activated, the means for activating the reheating device after the selection device is brought into the introduction state is configured by a delay circuit, which is present between the engine and the reheating device. For example, cold cooling water passes through a reheating device during the delay period, into which the cooling water present in the engine is introduced. Therefore, the temperature of the cooling water introduced into the reheating device is approximately equal to the temperature of the cooling water inside the engine. Therefore, the reheating device is started to operate accurately according to the temperature of the introduced cooling water.

When the reheating device is activated, if the means for activating the reheating device after the selection device is brought into the introduction state is constituted by means that responds to the heat load, when the heat load is small, only the selection device is activated, and the heat load The reheating device is also activated if the Therefore, the selection device is activated to introduce cooling water, and if the temperature of the cooling water is below a predetermined temperature, the reheating device is activated to heat the room. As heating progresses and the heat load decreases, the reheating device is stopped even if the cooling water temperature is below a predetermined temperature, but the selection device is activated and new cooling water is introduced from the engine. As a result, cooling water accumulates in the cooling water passage from the engine to the reheating device, and when the cooling water temperature drops below a predetermined temperature and the heat load increases again and the reheating device becomes operational, this reservoir The reheating device is temporarily prevented from operating due to the cooling water having a temperature below a predetermined temperature.

〔Example〕

FIG. 1 shows an embodiment of the present invention, and reference numeral 10 designates a schematic component of an air conditioner, including a heating heat exchanger 14 that uses the cooling water of a vehicle engine 12, which may be used as a driving force, as a heat source. , and a blower device 18 whose blowing capacity can be adjusted by an electric motor 16. The air conditioner 10 also includes a refrigeration cycle CC
The airflow generated in the air conditioner 10 by the operation of the blower 18 is provided with a cooling heat exchanger 24 that exerts a cooling effect under the operation of It is selectively cooled and heated in the container 14 and then discharged into the passenger compartment.

The cooling water path from the engine 12 to the heating exchanger 14 is provided with an electric pump 26 driven by an electric motor M and a solenoid valve 28 opened and closed by a solenoid SL. A selection device is configured to select whether to introduce or cut off water.

Further, a reheating device 30 for reheating the engine cooling water is disposed between the selection devices 26, 28 and the heat exchanger 14. As the reheating device 30, a known combustion type device that burns fuel and imparts heat generated to the cooling water is applied.

The mechanical components described above are operated by an electrical control circuit described next. The electrical control circuit includes a thermal load calculation circuit 32. A cabin temperature sensor 34, an outside air temperature sensor 36, and a cabin temperature setter 38 are connected to the input side of the heat load calculation circuit 32, and based on these input signals, the cabin air temperature is maintained at a set temperature. A load signal representative of the required thermal load Q is generated. The heat load calculation circuit 32 may be an analog calculation circuit or a digital calculation circuit, both of which are publicly known.

The comparator 40 compares the load signal with a preset first reference signal and produces an output that becomes high level when the heat load Q exceeds a value Qh ₁ that requires heating, and the comparator 42 compares the load signal with a first reference signal. is compared with a preset second reference signal, and when the heat load Q is smaller than the value _Qc1 that requires cooling, an output that becomes high level is generated. The difference between the values of the first and second reference signals of comparators 40, 42 indicates a blown area that requires neither cooling nor heating.

When the heat load Q indicates the cooling range, the high level output of the comparator 42 energizes the drive circuit 44 to operate the refrigeration cycle CC and activate the cooling heat exchanger 24.

Also, when the heat load Q indicates the heating range, the comparator 4
A high level output of 0 energizes the electric pump 26 and solenoid valve 28 to circulate engine cooling water into the path. In such a case, the delay circuit 46 delays the high level output, so that the reheating device 30 enters the operating state later than the time when the circulation of the cooling water starts.

The output of the delay circuit 46 is applied to the gate 48,
The gate 48 determines whether the reheating device 30 should be operated or stopped. The gate 48 has a low temperature switch 50.
A detection signal from the high temperature switch 52 is also introduced. The low temperature switch 50 generates a high level detection signal when the temperature of the cooling water introduced into the inlet of the reheating device 30 is lower than a preset temperature that requires reheating, and the high temperature switch 52 generates a high level detection signal when the temperature of the cooling water introduced into the inlet of the reheating device 30 is lower than a preset temperature that requires reheating. A high level detection signal is generated when the temperature of the cooling water exiting the outlet of the device 30 is higher than a preset temperature indicating excessive reheating.

Therefore, the reheating device 30 is operated after the time specified in the delay circuit 46 has elapsed since the cooling water started circulating in the path passing through the heating heat exchanger 14 and when the necessary temperature conditions are satisfied. start.

Therefore, after the electric pump 26 and the solenoid valve 28 start circulating cooling water for heating, the cooling water at a temperature lower than the operating temperature of the low temperature switch 50 is introduced into the reheating device 30, and the engine 12 is newly heated. At the point when cooling water having a temperature approximately equal to that of the cooling water is introduced, the gate 46 closes the reheating device 3.
To allow zero operation, a small amount of cold cooling water will not cause the reheating device to run undesirably and then shut down immediately.

The load signal generated by the thermal load calculation circuit 32 is converted by the air flow rate control circuit 54 into a signal representing the level of air blowing capacity of the air blower 18, and the rotational speed of the electric motor 16 is controlled via the drive circuit 56. This shows an example of the control characteristics of the air blowing amount control circuit 54, and air blowing amounts are set in stages B ₁ to B ₅ corresponding to the magnitude of the thermal load Q. here,
When the heat load B is in the cooling region C, which is smaller than the cooling set point Bc ₁ , the air flow rate B gradually increases as the heat load Q becomes smaller, while the heat load B is lower than the heating set point Bh _1. In the case where the heating area H is large, the amount of air blown B gradually increases as the heat load Q increases. Further, when the heat load Q is in the air blowing region V between the set point Qh ₁ and Qc ₁ , the air blowing amount B takes a predetermined value.

FIG. 3 shows another embodiment of the present invention,
A comparator 58 is connected in place of the delay circuit 46 in the embodiment described above. The comparator 58 compares the heat load signal with a preset third reference signal,
When the heat load Q is larger than the value Qh ₂ in the heating region, a high level output is generated.

Therefore, when the air conditioner works as a heating device, if the heat load Q is small and is in the region surrounded by the values Qh ₁ and Qh ₂ , the electric motor 26 and the solenoid valve 28 only circulate the cooling water. , the reheating device 30 is not activated. However, if the heat load Q is relatively large and is greater than the value Qh ₂ , the reheating device 30 is activated and assists the heating action of the heating heat exchanger 14 .

Although the present invention has been described above with reference to two embodiments, the implementation of the present invention is not limited to these embodiments. For example, the electrical control circuit described above is
The functions may be performed by a control program using a microcomputer.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the overall configuration of an embodiment of the present invention, Fig. 2 is a characteristic diagram showing the operating characteristics in Fig. 1, and Fig. 3 is a block diagram of main parts showing a modified embodiment of the present invention. It is. [Explanation of symbols], 10... air conditioner, 12...
Engine, 14... Heating heat exchanger, 18... Air blower, 26, 28... Electric pump and solenoid valve forming a selection device, 30... Reheating device, 32... Heat load calculation circuit, 40, 58 ... Comparator, 46 ... Delay circuit.

Claims (1)

[Scope of Claims] 1. An air conditioner equipped with a heating heat exchanger that uses engine cooling water as a heat source and a blower whose blowing capacity can be adjusted, the cooling water flowing from the engine to the heat exchanger. a selection device for selecting introduction/shutoff; a reheating device installed in a cooling water passage from the engine to the heat exchanger to reheat the engine cooling water; and the selection device for adjusting the temperature of the vehicle passenger compartment. and a control device for operating the reheating device, the control device operating the reheating device when the temperature of the cooling water from the engine is below a predetermined temperature, and the control device for operating the reheating device when the temperature of the cooling water is above the predetermined temperature. An air conditioning control device for a vehicle, comprising: a temperature switch for inactivating the device; and, when activating the reheating device, means for activating the reheating device after placing the selection device in an introduced state.