JPH04252720A - Air-conditioning control device for vehicle - Google Patents

Abstract

PURPOSE:To bring an actual blowing air temperature near to a target blowing air temperature so as to satisfy the responsiveness and stability of the air- conditioning control device for a vehicle. CONSTITUTION:An air-conditioning control device 100 for a vehicle determines the control quantity of an air-mixing damper 6 in an open-loop control or in a feedback control by means of an ECU 7 on the basis of the output signals from respective sensors or the actual blowing air temperature. And, in accordance with the followup error of the actual blowing air temperature to a target blowing air temperature or with the time rate of change of the followup error, the air-mixing damper 6 is driven by selectively using the control quantity determined above. Thus, when responsiveness is required, before the deviation of the actual blowing air temperature from the target blowing air temperature appears, the control of the blowing air temperature is carried out to obtain quick responsiveness. When the actual blowing air temperature is in close vicinity to the target blowing air temperature and stability is required, a stable blowing air temperature control can be carried out by PID control.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioning control system for a vehicle that can quickly and stably control the temperature inside a vehicle to a target value.

0002

BACKGROUND OF THE INVENTION Conventionally, in a vehicle air conditioning control system, blowing air temperature control as described below is known as a method for controlling the temperature inside a vehicle to a target value. As an example,
During steady state, open-loop control uses a control formula that calculates the damper opening of the air mix damper.In other words, the air mix damper opening is calculated from the target outlet air temperature, evaporator downstream air temperature, and engine cooling water temperature. do. During a transient period, there is a feedback control method for the blown air temperature, that is, a method of detecting the actual blown air temperature and controlling the air mix damper opening according to the deviation from the target blown air temperature.

As another example, when the target outlet air temperature is approaching and the target outlet air temperature is in a stable state, at least an integral term of the deviation between the vehicle interior temperature and the target outlet air temperature is added to the vehicle interior temperature, the target outlet air temperature, and the disturbance factor. In addition, the adjustment amount of the air mix damper is calculated and controlled. In the non-approach stable state, there is a method of calculating and controlling the adjustment amount of the air mix damper by proportional calculation with the above-mentioned integral term set to zero. Furthermore, some techniques for controlling the temperature of the blown air by correcting the voltage of the blower motor have also been put into practical use.

0004

However, there is a difference between the target outlet air temperature and the actual outlet air temperature, which is controlled based on the air mix damper opening calculated using the conventional control formula, due to environmental conditions (air conditioning control equipment Deviations occur due to differences in the air flow rate (and the temperature around the duct), the amount of air flow, and the fact that the control formula is an approximation formula. Therefore, if open-loop control using the above control formula is performed during steady state, deviations will occur in the outlet air temperature.
As a result, the system shifts to feedback control for the temperature of the blown air. In other words, there is a problem in that a hunting phenomenon occurs between open loop control and feedback control. In addition, if only the proportional calculation is performed in the conventional non-approach stable state, there may be a situation where a deviation remains, and furthermore,
There was also a problem with responsiveness because feedback control was performed after the deviation actually appeared.

[0005]Furthermore, vehicle air conditioning control systems are equipped with detailed systems that divide the interior of the vehicle into zones such as the driver's seat, passenger seat, rear left and right seats, and upper and lower body zones in order to make driving more comfortable. Air conditioning control is desired. For this purpose, it is necessary to control the temperature of the blowing air so that the air at the targeted temperature can be reliably sent out. Here, as a unit of the vehicle air conditioning control device, as shown in FIGS. 7 and 8,
Horizontal units Us are the mainstream. Although this device is easy to apply to long and narrow spaces, it has a problem in that the ventilation passage inside the unit is long and the ventilation resistance is large, as shown by the dashed line in FIG. Therefore, the above-mentioned horizontal unit U
There is a tendency for a center-placed unit Uc as shown in FIGS. 9 and 10 to be used instead of s. Since this center-mounted unit Uc has a short ventilation path within the unit, it can reduce ventilation resistance, reduce power consumption, and save space, as shown by the two-dot chain line in FIG. Further, since the unit configuration can be made symmetrical with respect to the direction of travel of the vehicle, there is an advantage that temperature control in the left and right directions in the vehicle interior is easy.

As is clear from FIG. 11, the change in air volume indicated by the horizontal width Ucw with respect to the change in the degree of clogging in the ventilation resistance curve of the center-placed unit Uc is the same as the ventilation resistance curve of the horizontally placed unit Us. This is larger than the change in air volume indicated by the width Usw with respect to the change in the degree of clogging. As shown in Figure 12, which shows the relationship between the degree of clogging and the amount of temperature change in relation to the outside air temperature, the influence of changes in the degree of clogging on the cabin temperature differs depending on the outside air temperature. The lower the temperature is below 10°C, the more the negative temperature change amount with respect to the increase in the degree of clogging is increased, and the temperature inside the vehicle is lowered. In addition, the higher the outside temperature is 10℃ or higher,
The amount of temperature change in response to an increase in the degree of clogging is increased to raise the temperature inside the vehicle. Therefore, compared to a vehicle air conditioning control device using a horizontal unit Us, for the same change in the degree of clogging, a vehicle air conditioning control device using a center placement unit Uc will significantly increase or decrease the amount of air introduced into the vehicle interior. A problem has arisen in which temperature changes become large.

The present invention has been made to solve the above-mentioned problems, and its purpose is to bring the actual blowing air temperature closer to the target blowing air temperature while satisfying responsiveness and stability. An object of the present invention is to provide a vehicle air conditioning control device.

[0008]

[Means for Solving the Problems] The structure of the invention for solving the above problems is such that when calculating the target blowing air temperature based on factors such as the vehicle interior temperature, the vehicle exterior temperature, and the set temperature, a first calculating means that adds a physical quantity that changes depending on the adhesion as a factor and determines an adjustment amount of the blowing air temperature control device based on the target blowing air temperature; and detecting the actual blowing air temperature as a feedback signal; a second calculation means for determining an adjustment amount of the blowout air temperature adjusting device according to a deviation from the target blowout air temperature; and a tracking error of the actual blowout air temperature with respect to the target blowout air temperature, or a tracking error thereof. If the amount of change over time is large, the blowout air temperature adjustment device is driven based on the adjustment amount determined by the first calculation means, and the tracking error of the actual blowout air temperature with respect to the target blowout air temperature is or control means for driving the blown air temperature adjusting device based on the adjustment amount determined by the second calculation means when the amount of change over time of the tracking error is small. .

[0009]

[Operation] When calculating the target outlet air temperature using factors such as the vehicle interior temperature, vehicle exterior temperature, and set temperature, the first calculation means further adds the amount of dust adhesion or a physical quantity that changes depending on the dust adhesion as a factor. The adjustment amount of the blowout air temperature control device is determined based on the target blowout air temperature. Further, the second calculation means detects the actual temperature of the blown air as a feedback signal, and determines the adjustment amount of the blown air temperature adjusting device according to the deviation from the target blown air temperature. When the tracking error of the actual blowing air temperature with respect to the target blowing air temperature or the amount of change over time of the tracking error is large and responsiveness is required, the control means adjusts the adjustment determined by the first calculation means. The blown air temperature control device is driven based on the amount. Therefore, the actual temperature of the blown air quickly approaches the target blown air temperature. Further, when the following error or the amount of change over time of the following error is small and stability is required, the control means controls the blowing air temperature adjusting device based on the adjustment amount determined by the second calculation means. to drive. Therefore, the actual temperature of the blown air stably approaches the target blown air temperature.

0010

EXAMPLES The present invention will be explained below based on specific examples.

FIG. 1 is a block diagram showing a vehicle air conditioning control device according to the present invention.

The vehicle air conditioning control system 100 makes air blown by a blower motor 11 pass through a dust filter 21 which is an anti-dust filter to obtain clean air, and then the air is cooled and dehumidified by an evaporator 12 . Then, the air mix damper 6 is driven by the servo motor 14 via the link mechanism 15, and the air is divided into air that passes through the heater 13 and air that bypasses the heater 13. By mixing the air downstream, a target air temperature is created, and the air is blown out from the upper duct 16 and lower duct 17. The blown air temperature control device is composed of an air mix damper 6, a servo motor 14, a link mechanism 15, and the like.

As shown in FIG. 3, the dust filter 21 is constructed by bending a filtering medium 21a in a zigzag shape to enlarge the filtering area and storing it in a case 21b. A hole 21c is provided at a predetermined location on the filter surface of the filter medium 21a of the dust filter 21 through which the air from the blower motor 11 passes.
is formed. Further, the dust sensor 22 is a separate type composed of first and second flow rate sensors 22a and 22b. One first flow velocity sensor 22a is disposed adjacent to the hole 21c of the dust filter 21, and detects the flow velocity of the wind passing through the hole 21c. Also, the other second
The flow rate sensor 22b is disposed near the first flow rate sensor 22a and detects the flow rate of the wind passing through the filtering surface of the dust filter 21. That is, the dust sensor 22 detects a physical quantity that changes depending on dust adhesion. The size of the hole 21c of the dust filter 21 is the minimum size necessary to enable the first flow rate sensor 22a to detect the flow rate of the wind passing through it, and is set so as not to reduce the filtration performance of the dust filter 21 as a whole. Set to .

Furthermore, as shown in FIG. 4, the first and second flow velocity sensors 22a and 22b may be arranged at the corners of the case 21b of the dust filter 21. In this case, the first and second flow rate sensors 22a, 22b and the dust filter 2
1 and the hole 21c as a unit, the dust filter 21
Replace when replacing. The second flow rate sensor 22b includes
Dust filter piece 21d with the same characteristics as the dust filter 21
correspond.

[0015] The air conditioning control device 100 is provided with an electronic control unit (hereinafter referred to as ECU) 7. ECU7
The output signal TR from the inside air temperature sensor 1, the output signal TAM from the outside air temperature sensor 2, the output signal TS from the solar radiation sensor 3, the output signal TSET from the temperature setting device 10 of the operation panel, and the output from the dust sensor 22. Signal VDUS
T is input respectively.

Here, the degree of clogging (resistance coefficient) ξb and (Va/Vb)2 of the dust filter 21 are shown in FIG.
There is a correlation as shown in That is, the degree of clogging ξb of the dust filter 21 is determined by the degree of clogging ξb of the first flow velocity sensor 22a.
The flow velocity Va of the air passing through the hole 21c of the dust filter 21 is detected by the flow velocity V of the air passing through the dust filter 21 detected by the second flow velocity sensor 22b.
It is calculated directly based on b. And (Va/V
b) 2 or (Va/Vb) is the output signal VDUST from the dust sensor 22. Incidentally, the dust sensor 22 may be of an integrated type in addition to the above-mentioned separate type. In the case of a separate type, the first and second flow rate sensors 2
It is necessary to perform correction between 2a and 22b. Further, the dust sensor 22 can also be a self-heating thermistor.

Based on the above output signals and using the correction constant C, the target air temperature TAO blown out from the upper duct 16 or the lower duct 17 of the air conditioning control device 100 is determined by the following equation.

[Math. 1]TAO={KSET+KDUST(TAM-1
0)×VDUST}×TSET-KR×TR-KAM×
TAM-KS×TS+C Note that KSET is the temperature setting gain, KDUST is the clogging degree gain, KR is the inside air temperature gain, KAM is the outside air temperature gain, and KS is the solar radiation gain.

Furthermore, the ECU 7 includes an output signal TE from the evaporator rear temperature sensor 4 downstream of the evaporator 12, and a heater 13.
The output signals TW from the water temperature sensors 5 are respectively input. Based on each of the above output signals, the air conditioning control device 10
The damper opening degree SWn, which is the adjustment amount of the air mix damper 6 such that the target air temperature TAO blown out from the upper duct 16 or the lower duct 17 at 0, is determined by the following equation.

[Math. 2] SWn=(TAO-TE)/(TW-TE)
...... Control equation (1) Here, control equation (1) is an approximate equation, which includes the evaporator rear temperature sensor 4 downstream of the evaporator 12, the opening degree of the air mix damper 6 by the servo motor 14, and the heater 13. The temperature characteristics determined by the water temperature sensor 5 have non-linearity.

[0019] Furthermore, due to differences in the blowout air speed (air volume), etc., and looseness and variations in the assembly of the air mix damper 6, its link mechanism 15, etc., the actual blowout air temperature TAO' deviates from the target blowout air temperature TAO. . Therefore, in order to obtain an accurate actual blowing air temperature TAO', in the top blowing mode, the upper duct 16 that blows air to the upper part of the vehicle interior is used.
The deviation En between the output signal TAV from the upper outlet air temperature sensor 8 and the target outlet air temperature TAO is determined. That is, En=TAO-TAO'. Then, the opening correction amount of the air mix damper 6 is determined from the proportional gain KP, the integral time Ti, the differential time TD, and the sampling time θ for performing discrete value control in the ECU 7. This correction amount is calculated as the damper opening SWn, which is the previous adjustment amount of the air mix damper 6.
In addition to −1, the damper opening SWn, which is the current adjustment amount,
is calculated from the following formula.

[Math. 3] SWn=SWn-1+KP{(En-En-1)+
(θ/Ti)En + (TD/θ)(
En-2En-1+En-2)}
...... Control formula (2) En is the deviation between the actual outlet air temperature TAO' and the target outlet air temperature TAO at the time of sampling this time, En-1 is the deviation at the time of the previous sampling, and En-2 is the deviation from the time before the previous one. It shows the deviation during sampling. Then, the ECU 7 controls the servo motor 1 so that the air mix damper 6 has the damper opening degree SWn.
4 is driven and controlled. Also, in the lower blowing mode, similar control is performed using the output signal TAH from the lower blowing air temperature sensor 9 in the lower duct 17 that blows air to the lower part of the vehicle interior.

The above two control equations (1) or the control equation (
2) The damper opening degree SWn of the air mix damper 6 is controlled by selecting according to the input status of each sensor, etc. In other words, the control formula (1) determines the damper opening SW of the air mix damper 6 regardless of the actual temperature of the blown air.
Since n is determined, if there is a transient change in the set temperature, it is possible to respond immediately and supply air with a new blowout air temperature. On the other hand, control formula (2) detects the actual temperature of the blown air and uses PID control to determine the damper opening SWn of the air mix damper 6, so structural errors around the air mix damper 6, It is possible to compensate for errors in the temperature of the blown air due to non-linearity of temperature characteristics after air mixing, making it possible to control the temperature of the blown air accurately.

Next, the EC used in the device of this embodiment
The processing procedure of U7 will be explained based on the flowchart of FIG. 2.

After performing the initial settings in step 100,
Proceeding to step 102, output signals from each sensor etc. are read and stored. Further, in step 104, the output signal VDUST from the dust sensor 22 is read and stored. Next, the process moves to step 106, where the target outlet air temperature TAO is calculated using the above-mentioned formula. Next, the process moves to step 108, where input changes to each switch, etc. are determined. Here, the damper opening degree S of the air mix damper 6 is
It is determined whether responsiveness is required for the control of Wn. For example, the output signal TS from the temperature setting device 10
It is determined whether the ET has changed. If there is no change in the input of each switch, etc., the determination in step 108 is N.
0, the process moves to step 110, and it is determined whether or not the sampling time θ seconds performed under normal sampling control has elapsed. Here, if the sampling time has not elapsed for θ seconds, the process returns to step 102 and the same process is repeated.

[0023] When the sampling time θ seconds has elapsed, the process moves to step 112. In step 112, the blowout mode is read, and the process moves to step 114, where it is determined whether the read blowout mode is FACE mode or not. If the blowout mode is FACE mode, the process moves to step 116 and TAO'=TAV. Here, the blowout mode read in step 112 is FA
If it is not the CE mode, the determination at step 114 is NO, and the process moves to step 118, where it is determined whether the read blowout mode is the FOOT mode. If the blowout mode is the FOOT mode, the process moves to step 120,
Let TAO'=TAH. Furthermore, if the blowout mode read in step 112 is not FOOT mode, the determination in step 118 is NO and the process moves to step 122, where B/L (bi-level) is an intermediate mode between FACE mode and FOOT mode. mode, the average value of TAV and TAH is used as shown in the following equation.

[Math 4] TAO’=(TAV+TAH)/2

0024
Next, the process moves to step 124, where it is determined whether the actual outlet air temperature TAO' is close to the target outlet air temperature TAO. Here, for example, |TAO-T
It is determined whether AO'|≦5. That is, if the deviation is within 5°C, it is assumed that the approach is in a stable state and the process moves to step 126, where the opening SW of the air mix damper 6 is changed.
Find n based on control equation (2). Next, the process moves to step 128, where the output signal of the determined opening SWn of the air mix damper 6 is outputted to the servo motor 14 for control, and is stored as SWn-1 in order to determine the next adjustment amount. Returning to step 102, similar processing is executed thereafter.

[0025] If in step 108 there is a change in the input of each switch, contrary to the above, or if step 124
If the deviation exceeds 5°C and it is a non-approach stable state, the process moves to step 130 and the air mix damper 6
The opening degree SWn of is determined based on the control equation (1). Then, the process moves to step 128 described above, and similar processing is executed. Here, the first calculation means is steps 102, 104, 106 and step 130 in the above program, and the second calculation means is steps 102, 10.
4, 106 and step 126, and the control means are accomplished in step 108 and step 124. In the above-mentioned program, only the control of the air mix damper 6 is shown, and the air volume control of the blower, outlet, etc. is performed according to the target blowout air temperature TAO by a known control method.

In the above embodiment, the air mix damper 6
The servo motor 14 is used to drive the
Instead, a similar effect can be obtained by using a pulse motor and controlling by outputting pulses that actuate the target damper opening by the difference between the actual damper opening and the target damper opening. In the above embodiment, control was performed with emphasis on responsiveness using control formula (1) when the settings of each switch were changed. However, this condition does not apply when changing the blowout temperature It is also possible to shift to the control using control formula (1) using the following conditions. For example, when the outlet is automatically selected according to the required outlet temperature, control may be performed using control formula (1) when the outlet is switched. When this appears, control using control equation (1) may be performed.

By using the vehicle air conditioning control device of the present invention, an accurate and stable outlet air temperature can be obtained by the outlet air temperature feedback control during steady state, and a control formula for the damper opening of the air mix damper can be used at transient times. Open-loop control improves responsiveness. By executing this blown air temperature control, the characteristics shown in FIG. 6 were obtained. That is, in the vehicle air conditioning control device of the present invention, even if the outside air temperature changes from -20°C to 40°C and the degree of clogging changes from 0 mmAq to 46 mmAq, the amount of temperature change is extremely accurately controlled within ±0.5°C. It will be possible. Therefore, the occupants do not feel any temperature difference in the vehicle interior.

It should be noted that the formula for determining the target outlet air temperature TAO mentioned above includes the output signal VDUST from the dust sensor 22.
However, as the amount of dust adhesion or a physical quantity that changes depending on the amount of dust adhesion, it is also possible to use, for example, a signal corresponding to the number of travel distances when relatively the same area is within the travel range.

[0029]

Effects of the Invention The present invention is constructed as described above, and includes a first calculating means for determining the amount of adjustment of the outlet temperature adjusting device in open loop control, and a first calculating means for determining the amount of adjustment of the outlet temperature adjusting device in feedback control. The second calculation means and the determined adjustment amount are selectively used to drive the blowout temperature adjustment device depending on the magnitude of the tracking error of the actual blowout air temperature with respect to the target blowout air temperature or the temporal change amount of the tracking error. According to the vehicle air conditioning control device of the present invention, when responsiveness is required,
Blowout air temperature control can be performed before a deviation of the actual blowout air temperature from the target blowout air temperature appears, and prompt responsiveness can be obtained. Furthermore, when the actual temperature of the discharged air is close to the target temperature of the discharged air and stability is required, the PID control has the effect that stable temperature control of the discharged air can be performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a vehicle air conditioning control device according to a specific embodiment of the present invention.

FIG. 2 is a flowchart showing a processing procedure of an ECU used in the device of the embodiment.

FIG. 3 is a perspective view of a dust filter provided with first and second flow rate sensors.

FIG. 4 is a partial perspective view of the dust filter showing another arrangement position of the first and second flow rate sensors.

[Fig. 5] Dust filter clogging degree ξb and (Va/
FIG. 3 is a characteristic diagram showing the correlation with Vb)2.

FIG. 6 is a characteristic diagram showing the relationship between the degree of clogging and the amount of temperature change in accordance with the outside air temperature in the same embodiment device.

FIG. 7 is a plan view schematically showing a horizontal unit of an air conditioning control device in a vehicle.

FIG. 8 is a side view of FIG. 7;

FIG. 9 is a top view schematically showing a center unit of an air conditioning control device in a vehicle.

FIG. 10 is a side view of FIG. 9;

FIG. 11 is a characteristic diagram showing the relationship between the ventilation resistance curve and the fan Δp-Q characteristic, which changes depending on the degree of clogging in the horizontal unit and center unit of the vehicle air conditioning control device.

FIG. 12 is a characteristic diagram illustrating the relationship between the degree of clogging and the amount of temperature change in a horizontal unit and a center unit of a conventional vehicle air conditioning control device in response to outside air temperature.

[Explanation of symbols]

1-Inside air temperature sensor 2-Outside air temperature sensor
3-Solar radiation sensor 4-Evaporator rear temperature sensor 5-Water temperature sensor
6-Air mix damper 7-ECU (electronic control unit) 8-Upper outlet air temperature sensor 9-Lower outlet air temperature sensor 10-Temperature setting device 11-Blower motor 12-Evaporator 13-Heater 14-Servo motor 15-Link Mechanism 16-upper duct 17-lower duct 2
1-Dust filter

Claims (1)

[Claims] [Claim 1] When calculating the target blowing air temperature based on factors such as the vehicle interior temperature, the vehicle outside temperature, and the set temperature, a dust adhesion amount or a physical quantity that changes depending on the dust adhesion is further added as a factor to calculate the target blowout air temperature. a first calculation means that determines the adjustment amount of the blowout air temperature adjusting device based on the temperature; and a first calculation means that detects the actual blowout air temperature as a feedback signal and adjusts the blowout air temperature according to the deviation from the target blowout air temperature. a second calculation means for determining the amount of adjustment of the device; and, if the following error of the actual blowing air temperature with respect to the target blowing air temperature or the amount of change over time of the following error is large, the first calculating means; The blowout air temperature adjusting device is driven based on the adjustment amount determined by the above, and when the tracking error of the actual blowout air temperature with respect to the target blowout air temperature or the temporal change amount of the tracking error is small, An air conditioning control device for a vehicle, comprising: control means for driving the blown air temperature control device based on the adjustment amount determined by the second calculation means.