JPH05178061A - Auxiliary heater controller or air conditioner for vehicle - Google Patents

Abstract

PURPOSE:To reduce electric power consumption of a auxiliary heater by calculating the rotational frequency of a compressor from a set air conditioning level and detected blow-off temperature of a heat exchanger, to carry current to the auxiliary heater when the blow-off temperature is equal to or lower than a predetermined value in the heating mode and the calculated rotational frequency of the compressor is equal to or higher than a predetermined value. CONSTITUTION:The blow-off temperature of one heat exchanger detected by a blow-off temperature detecting means 100 and a signal of an air conditioning level of a level setting means 110 are inputted to a compressor rotational frequency calculating means 120 for calculation. When an air conditioner is run in a heating mode, the blow-off temperature is equal to or lower than a predetermined value and the calculated rotational frequency is equal to or higher than a predetermined value, an auxiliary heater 8 is determined to be run by an auxiliary heater running judging means 130 to electrify the auxiliary heater 8 with an auxiliary heater controlling means 140. Thus, when the blow-off temperature and the rotational frequency of the compressor are lower than the predetermined values, in heating the electrification of the auxiliary heater 8 is stopped to save electric power.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary heater control device for an auxiliary heater provided as an auxiliary during heating operation in a vehicle air conditioner using a heat pump type air conditioner.

[0002]

2. Description of the Related Art In the operation control of an auxiliary power supply unit for a conventional heat pump type air conditioner, Japanese Patent Laid-Open No. 57-92642 discloses an indoor temperature detecting circuit, an outlet temperature detecting circuit, a microcomputer, an output control circuit, an auxiliary electric heating. The auxiliary electric heater is operated only when the compressor is operating and the blowout temperature is lower than a predetermined temperature. When the compressor starts operating and the auxiliary electric heater stops, a predetermined time a It discloses that the operation of the auxiliary electric heater is prohibited, and whether or not the capacity of the heat pump is sufficient is judged by the outlet temperature, and the auxiliary electric heater is used only when the capacity of the heat pump is insufficient. To achieve power saving control.

[0003]

However, in the above-mentioned reference, since the auxiliary electric heater is controlled only by the blowout temperature when the compressor is operating, when the blowout temperature is lower than the predetermined value, the compressor is There was a drawback that the auxiliary electric heater was turned on despite the remaining power, resulting in large power consumption. This has a great influence on the traveling distance and the like when the heat pump type air conditioner is used in an electric vehicle.

For this reason, the present invention limits the use of the auxiliary electric heater (auxiliary heater) not only by the blow-out temperature but also by the compressor rotation speed, and reduces the power consumption of the auxiliary heater. To provide a device.

[0005]

The present invention will now be described with reference to FIG. 1. A heat exchange cycle composed of at least two heat exchangers, an expansion valve, a compressor, and a four-way valve that changes the moving direction of the refrigerant. In a vehicle air conditioner having one heat exchanger and an auxiliary heater 8 in the air conditioning duct and performing heating or cooling by switching the four-way valve, the one heat exchanger arranged in the air conditioning duct. An outlet temperature detecting means 100 for detecting the outlet temperature of
A level setting means 110 for setting an air conditioning level, and a compressor rotation speed calculating means 120 for calculating the rotation speed of the compressor based on the blowout temperature detected by the blowout temperature detecting means 100 and the air conditioning level set by the level setting means. An auxiliary heater that determines the operation of the auxiliary heater when the operation of the air conditioner is in the heating mode, the blowout temperature is equal to or lower than a predetermined value, and the compressor rotation speed calculated by the compressor rotation speed calculation means is equal to or higher than the predetermined value. Auxiliary heater control means 1 for energizing the auxiliary heater 8 when the operation of the auxiliary heater 8 is determined by the operation determination means 130 and the auxiliary heater operation determination means 130.
And 40.

[0006]

Therefore, in the present invention, the auxiliary heater operation determination is made by the blowout temperature detected by the blowout temperature detecting means 100 and the compressor rotation speed calculated by the blowout temperature and the air conditioning level set by the level setting means 110. In the means 130, when it is determined that the air conditioner is in the heating mode, the blowout temperature is equal to or lower than the predetermined value, and the compressor rotation speed is equal to or higher than the predetermined value, the blowout is performed even though the compressor capacity is operating at the maximum. Since it is determined that the temperature is low, it is possible to make up for the insufficient heating of the heat exchanger on the one side provided in the duct by energizing the auxiliary heater 8, and the air conditioner is in the heating mode and the blowout temperature is set to a predetermined value. Even if it is less than the value, if the compressor speed is less than the predetermined value, it is judged that there is a spare capacity in the compressor. To stop the power supply to the auxiliary heater, in which the object can be achieved.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

The heat pump type air conditioner 1 shown in FIG. 2 has an inside air introduction port 3 and an outside air introduction port 4 at the uppermost stream of the air conditioning duct 2, and these inside air introduction port 3 and outside air introduction port 4 are inside and outside. It is opened and closed by the air switching door 5.

An air blower 6 is provided on the downstream side, and on the downstream side of the air blower 6, there are an in-duct heat exchanger 7, which constitutes a part of a heat exchange cycle described below, as a temperature adjusting means, and an electric heater. An auxiliary heater 8, an air mix door 9 that opens and closes the upstream side of the auxiliary heater 8, and a sub door 10 that opens and closes the downstream side of the auxiliary heater 8 are provided.

A vent outlet 11, a differential outlet 12, and a foot outlet 13 are opened at the most downstream side of the air conditioning duct 2, and are appropriately opened and closed by a mode door 15 to open the respective ducts 16, 17 and 18. The temperature of the vehicle interior is controlled by blowing it out into the vehicle interior (not shown).

In the heat exchange cycle, the heat exchanger 7 inside the duct, the expansion valve 19, the heat exchanger outside the duct 20, the four-way valve 21,
A compressor 22 and an accumulator 23 are connected in series by piping, and by switching the four-way valve 21, the compressor 22, the four-way valve 21, the duct heat exchanger 7, the expansion valve 19, the duct outside heat exchanger 20, and the four-way valve. 21, the heating heat exchange cycle that returns to the condenser 22 via the accumulator 23, the compressor 22, the four-way valve 21,
A heat exchange cycle for cooling is formed which returns to the compressor 22 via the outside duct heat exchanger 20, the expansion valve 19, the inside duct heat exchanger 7, the four-way valve 21, and the accumulator 23. Incidentally, 24 is an electric motor for rotating the compressor 22.

In the heating heat exchange cycle, the high-temperature and high-pressure gas refrigerant compressed by the compressor 22 reaches the duct heat exchanger 7 through the four-way valve 21. In this case, the heat exchanger 7 in the duct is a condenser (condenser).
The heat is radiated to the air passing through the in-duct heat exchanger 7 to condense the refrigerant into a low-temperature and high-pressure liquid refrigerant. This low-temperature high-pressure liquid refrigerant is
By passing through the expansion valve 19, it becomes a mist-like low-pressure low-temperature refrigerant, and reaches the duct outside heat exchanger 20. In this case, the outside-duct heat exchanger 20 serves as an evaporator (evaporator), and is vaporized by absorbing the heat of the air passing through the outside-duct heat exchanger 20, and becomes a high-temperature low-pressure gas refrigerant. , Reaches the accumulator 23 via the four-way valve 21, where gas-liquid separation is performed and returns to the compressor 22. As a result, the air passing through the air conditioning duct 2 is heated.

In the cooling heat exchange cycle, by switching the four-way valve 21, the flow of the refrigerant passing through the in-duct heat exchanger 7, the expansion valve 19 and the outside-duct heat exchanger 20 is reversed, whereby the duct. The air passing through the air conditioning duct 2 is cooled by the inner heat exchanger 7 acting as an evaporator and the outer duct heat exchanger 20 acting as a condenser.

In the air conditioner 1 having the above-mentioned structure, the inside air or the outside air sucked by the drive of the blower 6 from the inside air introduction port 3 or the outside air introduction port 4 selected by the inside / outside air switching door 5 is the heat exchanger in the duct. It is heated or cooled by passing through 7, and is blown into the vehicle interior through the ducts from the air outlets 11, 12, 13 selected by the mode door 15 to control the temperature inside the vehicle interior. Further, in the case of heating, in order to make up for the insufficient heating capacity of the heat exchanger 7 in the duct, the auxiliary heater 8 is energized via the control circuit 25, and the air mix door 9 and the sub door 10 are opened. The air heated by passing through the in-duct heat exchanger 7 can be further heated. Also, during cooling, the air mix door 9 and the sub door 10
Is closed to suppress the heat effect of the auxiliary heater 8 and the increase in air resistance.

In order to control the air conditioner 1, a microcomputer 26 is provided, and a signal from a temperature sensor 27 provided at a blowout position of the heat exchanger 7 in the duct is sent to A / A.
The signal is input through the D converter 28, and further, a signal from the operation panel 29 described below is input, processed according to a predetermined program, and a control signal is output. The microcomputer 26 is a publicly known computer including a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), an input / output port (I / O), etc., which are not shown.

The operation panel 29 includes an ON switch 31 for turning on and off the operation of the blower 6, a heating mode, a cooling mode,
A / C switch 31 for switching off mode, REC switch 32 for setting intake air mode to internal air circulation mode (REC), intake air mode for outside air introduction mode (FR)
E) FRE switch 33, the blowing mode is set to the differential blowing mode DEF switch 34, the blowing mode is set to the differential foot mode F / D switch 35, the blowing mode is set to the foot blowing mode FOOT switch 36, Set the blowout mode to bilevel mode B /
The L switch 37, the VENT switch 38 for setting the blowout mode to the vent blowout mode, the FAN switch 39 for setting the air volume of the blower 6, and the air conditioning level to full hot (F
/ H) to a full-cool (F / C) linearly configured slide switch.

The control signal output from the microcomputer 26 is input to the output circuits 42a to 42g, whereby the actuator 43a for driving the inside / outside air switching door 5, the blower 6, the motor 24 for driving the compressor, and the four-way valve. 21, the control circuit 25 for controlling the auxiliary heater 25, the actuator 43b for driving the air mix door 9 and the sub door 10, and the actuator 43c for driving the mode door 15 are controlled.

3 and 4 show flowcharts of programs for the compressor control and the auxiliary heater control executed by the microcomputer 26, which will be described below with reference to these flowcharts.

The compressor control, which constitutes a part of the air conditioning control which is started by turning on an ignition switch (not shown), is regularly started from the main routine of the air conditioning control in step 200 by a timer interrupt or a jap command. Then, in step 210, it is determined whether or not an abnormality has occurred, and in step 220, it is determined whether or not the drive of the blower (BLO) 6 is stopped. In this judgment, there is no abnormality and O
If it is determined that the blower 6 is being driven by turning on the N switch 30, the process proceeds to step 230 to make a determination on the A / C switch 31, and if an abnormality occurs or the blower 6 is stopped. When it is in the state, it proceeds to step 410.

In step 230, the A / C switch 31 is in the heat (HEAT) mode (heating mode).
If it is set to, the process proceeds to step 240 to execute the heating control, and if it is set to the cool (COOL) mode (cooling mode), the process proceeds to step 310 to execute the cooling control and set to OFF. If so, the process proceeds to step 410.

In the heating control starting from step 240, the primary set rotational speed N1 of the compressor is calculated in step 240. This calculation is set according to the characteristic diagram of the lever position of the air conditioning level setting device 40 and the compressor rotation speed shown in FIG. 5, and when the lever is in the full hot (F / H) position, the heating request is high. Therefore, the compressor speed is set to 5750 [rpm],
In the full-cool (F / C) position, since the heating request is low, the compressor rotation speed is set to 2000 [rpm], and the interval is linearly changed depending on the lever position.

After the primary set speed N1 is calculated in step 240, it is determined in step 250 whether or not the outlet temperature Te of the duct heat exchanger 7 is 45 ° C. or lower. In this determination, the outlet temperature Te
If it is determined that the temperature is 45 ° C. or lower, step 2
In step 60, the primary set rotational speed N1 is directly set as the secondary set rotational speed N2, and when the blowout temperature Te is 45 ° C. or higher, it is corrected in step 270 by the following mathematical expression 1.

[0023]

## EQU1 ## N2 = N1 + 150 (45-Te)

As a result, when the blow-out temperature Te is 45 ° C. or higher, the temperature difference compressor rotation speed is reduced to perform appropriate temperature control.

In step 280, the secondary set rotational speed N2 is 2000 [r which is the minimum rotational speed at which heating can be maintained.
pm] or less, it is determined that the secondary set rotational speed N2 is 2000 [rp]
m] or less, the secondary set rotational speed is maintained at 2000 [rpm] in step 290.

If the secondary set speed N2 is 2000 [rpm] or more in step 280, the secondary set speed N2 is 2000 in step 290.
After setting to [rpm], the routine proceeds to step 300, where the rotation speed N of the compressor 22 is calculated by the characteristic diagram shown in FIG. 7. In addition, this characteristic diagram shows 5
A hysteresis of 00 [rpm] is provided, and the rotation speed during the decrease is higher than the rotation speed during the increase so as to suppress a rapid change in the temperature during the decrease or increase of the compressor rotation speed. It has been set.

In the cooling control starting from the step 310, the 1 o'clock set speed N is set in the step 310.
1 is calculated. This calculation is set according to the characteristic diagram of the lever position of the air conditioning level setting device 40 and the compressor rotation speed shown in FIG.
When it is in position C), the cooling speed is high, so the compressor speed is set to 4500 [rpm] and full hot (F
/ H) position, the cooling demand is low, so the compressor rotation speed is set to 1500 [rpm], and the interval is linearly changed depending on the lever position. The reason why the maximum rotation speed and the minimum rotation speed are different during heating is that the heat exchange efficiency is higher during cooling than during heating.

In step 320, the outlet temperature Te is 6
Whether the temperature is 6 ° C. or higher is determined. If the temperature is 6 ° C. or higher, the primary setting engine speed N1 is directly set as the secondary setting engine speed N2 in step 330.
In the case of 0, it is corrected by the following mathematical formula 2.

[0029]

[Formula 2] N2 = N1-500 (Te-6)

As a result, when the blow-out temperature Te is 6 ° C. or less, the compressor rotation speed is reduced to control to prevent overcooling.

In step 350, step 340
It is judged whether or not the secondary set rotational speed N2 calculated in step S1 is less than or equal to the minimum rotational speed 1500 [rpm] capable of maintaining cooling, and if it is less than 1500 [rpm], the secondary setting is performed in step 360. Rotation speed N2 is 1500 [r
pm].

After the secondary set speed N2 is set in this way, it is determined in step 370 whether the blowout temperature Te is 2 ° C. or higher. When it is determined in this determination that the temperature is 2 ° C. or less, the timer is set in step 390, and it is determined in step 400 whether or not the timer has elapsed for 2 minutes.
This determination is a control for preventing freezing of the indoor heat exchanger 7. If the outlet temperature Te is 2 ° C. or less and 2 minutes have elapsed, the process proceeds to step 410 and the secondary set speed N2 is set to zero. Therefore, the compressor 22 is stopped to prevent freezing. If two minutes have not elapsed, the routine proceeds to step 300 to perform normal control.

At step 370, the outlet temperature Te
If it is determined that the temperature is 2 ° C. or higher, step 38
0, the timer is reset, and in step 300, the rotational speed N of the compressor 22 is changed from the secondary set rotational speed N2.
And returns to the main routine from step 420.

If there is an abnormality in the determination in step 210, if the blower 6 has stopped operating in the determination in step 220, or if it is turned off by the A / C switch 31 in step 230.
If is set in step 410, 2
The operation of the compressor 22 is stopped by setting the next set rotation speed N2 to zero.

Similar to the compressor control, the auxiliary heater control started from step 500 shown in FIG. 4 is periodically started from the main routine of the air conditioning control. The determination is made. If an abnormality occurs, the process proceeds to step 570 to turn off the auxiliary heater 8, and if no abnormality occurs, the process proceeds to step 520 to determine whether to drive the blower 6. In this determination, if the blower 6 is stopped, the process proceeds to step 570 described above, and if it is operating, the process proceeds to step 530.

In step 530, it is determined whether or not the A / C switch 31 is set to the heating mode. If it is other than heating, the process proceeds to step 570 described above, and if it is set to the heating mode. Step 54
The process proceeds to 0 to determine the outlet temperature Te. In this determination, 25 ° C as indicated in the box in step 540
Hysteresis is formed between 30 ° C and 30 ° C. When the temperature rises, control B shifts to control A at 30 ° C.
When the temperature drops, the control A shifts to the control B at 25 ° C. In the case of control A, it is determined that there is no request for the auxiliary heater 8 and the process proceeds to step 570, and in the case of control B, the process proceeds to step 550 to determine the primary set rotational speed N1.

In this determination, a hysteresis is formed between α and β (values shown in FIG. 5) shown in step 550, and when the rotational speed is increasing, α (for example, 5500 [ rpm]), the control shifts from the control D to the control C, and when the rotation speed decreases, the control C shifts to the control D at β (for example, 5000 [rpm]). In the control D, the process proceeds to step 570, and in the case of control C, the process proceeds to step 560 to start the energization of the auxiliary heater 8. After that, the process returns from step 580 to the main routine.

As described above, in the determinations in steps 540 and 550, assistance is provided only when the outlet temperature Te is below a predetermined value (control B) and the primary set rotational speed N1 is above a predetermined value (control C). The heater 8 is energized.

Further, even if the temperature is below a predetermined value (control B) in step 540, if the primary set speed N1 is below a predetermined value (control D), the compressor capacity has a surplus capacity. Since it can be determined that there is, the power supply to the auxiliary heater 8 is stopped to save power.

In the above embodiment, the compressor capacity is determined by the primary set speed N1. However, even if the compressor capacity is determined by the secondary set speed N2 calculated to calculate the actual compressor speed, The same effect can be obtained.

Further, the actual rotation of the compressor 22 can be detected by a rotation detector or the like and can be judged by this.

[0042]

As described above, according to the present invention,
In order to determine the condition for using the auxiliary heater by the blow-out temperature and the rotation speed of the compressor, when the blow-out temperature is below a predetermined value and the compressor rotation speed is below a predetermined value during heating, the power supply to the auxiliary heater is stopped. Therefore, power saving can be achieved.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a configuration of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of an air conditioner according to an embodiment of the present invention.

FIG. 3 is a flow chart of compressor control executed by a microcomputer.

FIG. 4 is a flow chart of auxiliary heater control executed by a microcomputer.

FIG. 5 is a characteristic diagram showing the relationship between the lever position of the air conditioning level setting device during heating and the primary set rotational speed N1.

FIG. 6 is a characteristic diagram showing the relationship between the lever position of the air conditioning level setting device during cooling and the primary setting rotation speed N1.

FIG. 7 is a characteristic diagram showing a relationship between a secondary set rotational speed N2 and a compressor rotational speed N.

[Explanation of symbols]

 8 Auxiliary heater 100 Blow-out temperature detecting means 110 Level setting means 120 Compressor rotation speed calculating means 130 Auxiliary heater operation judging means 140 Auxiliary heater control means

Claims (1)

[Claims] 1. A heat exchanger in a heat exchange cycle, which comprises at least two heat exchangers, an expansion valve, a compressor, and a four-way valve that changes the moving direction of the refrigerant, and an auxiliary heater in an air conditioning duct. In a vehicle air conditioner that performs heating or cooling by switching the four-way valve, a blowout temperature detecting means for detecting a blowout temperature of one heat exchanger arranged in the air conditioning duct, and an air conditioning level are set. Level setting means, compressor rotation speed calculation means for calculating the rotation speed of the compressor based on the blowout temperature detected by the blowout temperature detection means and the air conditioning level set by the level setting means, and the operation of the air conditioner in the heating mode. The blowout temperature is equal to or lower than a predetermined value, and the compressor rotation speed calculated by the compressor rotation speed calculation means is calculated. An auxiliary heater operation determining means for determining the operation of the auxiliary heater when is greater than or equal to a predetermined value, and an auxiliary heater control means for energizing the auxiliary heater when the operation of the auxiliary heater is determined by the auxiliary heater operation determining means. An auxiliary heater control device for a vehicle air conditioner, comprising: