JP3008137B2 - Auxiliary heater control device for vehicle air conditioner - Google Patents

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 a heating operation in a vehicle air conditioner using a heat pump type air conditioner.

[0002]

2. Description of the Related Art In the conventional operation control of an auxiliary power supply of a heat pump air conditioner, Japanese Patent Laid-Open No. 57-92642 discloses an indoor temperature detecting circuit, a blow-out temperature detecting circuit, a microcomputer, an output control circuit, an auxiliary electric heating circuit. The auxiliary heater is operated only when the compressor is operating and the blow-out temperature is equal to or lower than a predetermined temperature. When the operation of the compressor is started and the auxiliary heater is stopped, a predetermined time a Among them, the one that prohibits the operation of the auxiliary heater is disclosed, and it is determined whether or not the heat pump capacity is sufficient based on the blowing temperature, and the auxiliary heater is used only when the heat pump capacity is insufficient. To achieve power saving control.

[0003]

However, in the above-mentioned reference, since the auxiliary electric heater is controlled only by the blow-out temperature during the operation of the compressor, when the blow-out temperature is lower than a predetermined value, the auxiliary heater is controlled by the compressor. There is a drawback in that the auxiliary heater is turned on and power consumption is increased despite the extra power. This has a significant effect on the mileage and the like when the heat pump type air conditioner is used for an electric vehicle.

Therefore, the present invention restricts the use of an auxiliary electric heater (auxiliary heater) not only by the blowout temperature but also by the number of rotations of a compressor, thereby reducing the power consumption of the auxiliary heater. It is to provide a device.

[0005]

According to the present invention, referring to FIG. 1, a heat exchange cycle comprising at least two heat exchangers, an expansion valve, a compressor, and a four-way valve for changing a moving direction of a refrigerant. In a vehicle air conditioner that has one heat exchanger and an auxiliary heater 8 in an air conditioning duct and performs heating or cooling by switching the four-way valve, one heat exchanger disposed in the air conditioning duct Outlet temperature detecting means 100 for detecting the outlet temperature of
Level setting means 110 for setting an air-conditioning level; compressor rotation number calculating means 120 for calculating the number of rotations of the compressor based on the blowing temperature detected by the blowing 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 a heating mode, the blow-out temperature is equal to or lower than a predetermined value, and the compressor speed calculated by the compressor speed calculator is equal to or higher than a predetermined value. The operation determining unit 130 and the auxiliary heater control unit 1 that supplies electricity to the auxiliary heater 8 when the operation of the auxiliary heater 8 is determined by the auxiliary heater operation determining unit 130.
40.

[0006]

Therefore, in the present invention, the auxiliary heater operation determination is made based on the blow-out temperature detected by the blow-out temperature detecting means 100 and the compressor rotation speed calculated based on the blow-out 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 compensate for insufficient heating of the heat exchanger in one of the ducts by supplying electricity to the auxiliary heater 8, and when the air conditioner is in the heating mode and the blowout temperature is lower than the predetermined value. If the compressor speed is less than the specified value, it is determined that there is enough compressor capacity. 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 inlet 3 and an outside air inlet 4 at the uppermost stream of the air conditioning duct 2, and the inside air inlet 3 and the outside air inlet 4 are provided inside and outside. It is opened and closed by the air switching door 5.

On the downstream side, a blower 6 is provided, and on the downstream side of the blower 6, a heat exchanger 7 in a duct, which constitutes a part of a heat exchange cycle described below, and an electric heater as temperature control means. An auxiliary heater 8, an air mix door 9 that opens and closes an upstream side of the auxiliary heater 8, and a sub door 10 that opens and closes a 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 of the air-conditioning duct 2. The ducts 16, 17, 18 are opened and closed by a mode door 15 as needed. The temperature of the interior of the vehicle is controlled by blowing the air through a vehicle compartment (not shown).

The heat exchange cycle includes the heat exchanger 7 inside the duct, the expansion valve 19, the heat exchanger 20 outside the duct, the four-way valve 21,
The compressor 22 and the accumulator 23 are connected by piping in series, and the compressor 22, the four-way valve 21, the heat exchanger 7 in the duct, the expansion valve 19, the heat exchanger 20 outside the duct, and the four-way valve are switched by switching the four-way valve 21. 21, a heating heat exchange cycle returning to the condenser 22 through the accumulator 23, the compressor 22, the four-way valve 21,
This forms a cooling heat exchange cycle that returns to the compressor 22 via the heat exchanger outside the duct 20, the expansion valve 19, the heat exchanger inside the duct 7, the four-way valve 21, and the accumulator 23. Reference numeral 24 denotes an electric motor for rotating the compressor 22.

In the heating heat exchange cycle, the high-temperature and high-pressure gaseous 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 refrigerant is condensed into a low-temperature and high-pressure liquid refrigerant by releasing heat to the air passing through the duct heat exchanger 7. 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 heat exchanger 20 outside the duct. In this case, the heat exchanger 20 outside the duct serves as an evaporator (evaporator), and vaporizes by absorbing the heat of the air passing through the heat exchanger 20 outside the duct, and becomes a high-temperature low-pressure gas refrigerant. , Through the four-way valve 21 to the accumulator 23, where the gas-liquid separation is performed and the flow returns to the compressor 22. Thereby, the air passing through the air conditioning duct 2 is heated.

In the cooling heat exchange cycle, switching of the four-way valve 21 reverses the flow of the refrigerant passing through the heat exchanger 7, the expansion valve 19, and the heat exchanger 20 outside the duct. The air passing through the air conditioning duct 2 is cooled by the internal heat exchanger 7 serving as an evaporator and the external heat exchanger 20 serving as a condenser.

In the air conditioner 1 having the above configuration, the inside air or the outside air sucked by the drive of the blower 6 from the inside air inlet 3 or the outside air inlet 4 selected by the inside / outside air switching door 5 is supplied to the heat exchanger in the duct. 7 is heated or cooled by passing through the air passage 7 and blown into the vehicle interior through the ducts from the air outlets 11, 12, and 13 selected by the mode door 15, thereby controlling the temperature in the vehicle interior. In addition, in the case of heating, in order to compensate for the shortage of the heating ability by the heat exchanger 7 in the duct, the power supply to the auxiliary heater 8 is performed via the control circuit 25, and the air mix door 9 and the sub door 10 are opened. Thus, the air heated by passing through the heat exchanger 7 in the duct can be further heated. During cooling, the air mix door 9 and the sub door 10
In order to suppress the influence of heat 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 blowing position of the heat exchanger 7 in the duct is A / A.
A signal is input via a D converter 28 and further from an operation panel 29 described below, and is processed according to a predetermined program to output a control signal. The microcomputer 26 is a known unit including a central processing unit (CPU), a random access memory (RAM), a read-only memory (ROM), an input / output port (I / O), and the like (not shown).

An 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 inside air circulation mode (REC), and external air introduction mode (FR for intake air mode)
E), a FRE switch 33 for setting the blowing mode to the differential blowing mode, an F / D switch 35 for setting the blowing mode to the differential foot mode, a FOOT switch 36 for setting the blowing mode to the foot blowing mode, Set blowing mode to bi-level mode B /
An L switch 37, a VENT switch 38 for setting the blow mode to the vent blow mode, a FAN switch 39 for setting the air volume of the blower 6, and a full hot (F
/ H) from an air conditioning level setting device 40 which is a slide switch that linearly changes from full cooling (F / C) to full cooling (F / C).

Control signals output from the microcomputer 26 are input to 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, the four-way valve 21, a control circuit 25 for controlling the auxiliary heater 25, an actuator 43b for driving the air mix door 9 and the sub door 10, and an actuator 43c for driving the mode door 15 are controlled.

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

The compressor control which is a part of the air conditioning control which is started by turning on an ignition switch (not shown) is periodically started from a main routine of the air conditioning control in step 200 by a timer interrupt, a jump command or the like. In step 210, it is determined whether or not an abnormality has occurred, and in step 220, it is determined whether or not the driving of the blower (BLO) 6 is stopped. In this determination, no abnormality occurs 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 and the A / C switch 31 is determined. If an abnormality occurs or the blower 6 is stopped. If it is, the process proceeds to step 410.

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

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

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

[0023]

N1 = N1 + 150 (45-Te)

Thus, when the outlet temperature Te is equal to or higher than 45 ° C., the temperature difference compressor rotation speed is reduced to perform appropriate temperature control.

In step 280, the secondary set speed N2 is 2000 [r], which is the minimum speed at which heating can be maintained.
pm] or less, and the secondary set rotation speed N2 is set to 2000 [rpm
m] or less, in step 290, the secondary set rotation speed is maintained at 2000 [rpm].

In step 280, if the secondary set rotation speed N2 is 2000 [rpm] or more, in step 290, the secondary set rotation speed N2 is set to 2000 [rpm].
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. Note that this characteristic diagram shows 5
A hysteresis of 00 [rpm] is provided so that the rotation speed at the time of falling is higher than the rotation speed at the time of rising so as to suppress a rapid change in temperature at the time of falling or rising of the compressor speed. It is set.

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

In step 320, the blowing temperature Te becomes 6
It is determined whether the temperature is equal to or higher than ° C. If the temperature is equal to or higher than 6 ° C, the primary set rotational speed N1 is directly used as the secondary set rotational speed N2 in Step 330. If the temperature is equal to or lower than 6 ° C, Step 34 is performed.
At 0, correction is performed by the following equation (2).

[0029]

N2 = N1-500 (Te-6)

Thus, when the blow-out temperature Te is 6 ° C. or lower, control is performed so as to reduce the number of rotations of the compressor and suppress excessive cooling.

In step 350, step 340
It is determined whether or not the secondary set rotation speed N2 calculated in is less than or equal to the minimum rotation speed 1500 [rpm] capable of maintaining the cooling. If it is not more than 1500 [rpm], the secondary setting is made in step 360. The rotational speed N2 is set to 1500 [r
pm].

After the secondary rotation speed N2 is set in this way, it is determined in step 370 whether or not the blowout temperature Te is 2 ° C. or higher. If it is determined that the temperature is not more than 2 ° C. in this determination, a 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 the indoor heat exchanger 7 from freezing. If the blow-out temperature Te is 2 ° C. or less and 2 minutes have passed, the process proceeds to step 410 and the secondary set rotation speed N2 is set to zero. The compressor 22 is stopped to prevent freezing. If two minutes have not elapsed, the routine proceeds to step 300, where normal control is performed.

At the step 370, the blowing temperature Te
Is determined to be 2 ° C. or higher, step 38
0, the timer is reset, and in step 300, the rotational speed N of the compressor 22 is calculated from the secondary set rotational speed N2.
Is calculated, and the process returns to the main routine from step 420.

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

The auxiliary heater control started at step 500 shown in FIG. 4 is periodically started from the main routine of the air conditioning control, similarly to the compressor control. The determination is made. If an abnormality has occurred, the routine proceeds to step 570, where the auxiliary heater 8 is turned off. If no abnormality has occurred, the routine proceeds to step 520, where the drive of the blower 6 is determined. In this determination, if the blower 6 is stopped, the process proceeds to step 570, and if it is operating, the process proceeds to step 530.

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

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

As described above, in the determinations in steps 540 and 550, the assist is provided only when the blowout temperature Te is equal to or lower than the predetermined value (control B) and the primary set rotation speed N1 is equal to or higher than the predetermined value (control C). The heater 8 is energized.

Even if the temperature is equal to or lower than the predetermined value (control B) in step 540, if the primary set rotation speed N1 is equal to or lower than the predetermined value (control D), the compressor capacity has an extra capacity. In order to determine 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 based on the primary set speed N1. However, even if it is determined based on the secondary set speed N2 calculated for calculating the actual compressor speed, the above-described case is obtained. A similar effect can be obtained.

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

[0042]

As explained above, according to the present invention,
In order to determine the conditions for using the auxiliary heater based on the blowout temperature and the rotation speed of the compressor, if the blowout temperature is lower than a predetermined value and the compressor rotation speed is lower than a predetermined value during heating, the power supply to the auxiliary heater is stopped. As a result, power saving can be achieved.

[Brief description of the 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 flowchart of compressor control executed by the microcomputer.

FIG. 4 is a flowchart of auxiliary heater control executed by the microcomputer.

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

FIG. 6 is a characteristic diagram showing a relationship between a lever position of an air-conditioning level setter during cooling and a primary set rotation speed N1.

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

[Explanation of symbols]

 Reference Signs List 8 auxiliary heater 100 blow-out temperature detecting means 110 level setting means 120 compressor rotation speed calculating means 130 auxiliary heater operation determining means 140 auxiliary heater controlling means

Claims (1)

(57) [Claims] 1. An air conditioning duct having at least two heat exchangers, one heat exchanger of a heat exchange cycle constituted by an expansion valve, a compressor, and a four-way valve for changing a moving direction of a 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, an air temperature detection unit that detects an air temperature of one of the heat exchangers disposed in the air conditioning duct, and an air conditioning level are set. Level setting means; compressor rotation speed calculation means for calculating a rotation speed of the compressor based on the blowing temperature detected by the blowing temperature detection means and the air conditioning level set by the level setting means; and operating the air conditioner in a heating mode. And the compressor rotation speed calculated by the compressor rotation speed calculation means when the blowout temperature is equal to or lower than a predetermined value. 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 controlling 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: