JPH0492710A - Air-conditioning device for vehicle - Google Patents

Abstract

PURPOSE:To perform automatic control of temperature in a room even during failure in operation of an inner air sensor by determining a correction value by means of a measuring signal from the inner air sensor based on a difference with a preceding estimating value to compute a new estimating value, and controlling a discharge temperature based on the estimating value during failure in operation of the inner air sensor. CONSTITUTION:During air-conditioning operation, output signals from an evaporator sensor 20, an inner air sensor 21, a solar radiation sensor 22, and an open air sensor 23 are inputted. A difference between an input signal Trso estimated control period TI seconds before and inputted from the inner air sensor and a measurement signal Tr from the inner air sensor 21 is determined by a control circuit 24 to compute a correction value DELT. Based on the correction value DELT and the measurement signal Tr, an estimating value Trso of the inner sensor after the control period TI is determined and from the estimating value Trso and an output from other sensor, a target discharge temperature TAO is determined. In which case, when it is decided that a sensor is failed in operation, the estimating value Trso is used as the measuring signal Tr from the inner sensor 21, and based on the estimating value Trso and the correction value DELT, the estimating temperature Trso being an inner sensor measurement value after a lapse of TI seconds is determined to compute the target discharge temperature TAO.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an air conditioner for a vehicle that can back up the temperature in the vehicle interior when, for example, the interior air sensor malfunctions and the temperature inside the vehicle cannot be measured. .

[Prior Art] Air conditioners for vehicles include sensors such as an inside air sensor that measures the temperature inside the vehicle, an outside air sensor that measures the outside natural temperature, and a solar radiation sensor that measures the state of sunlight. When automatically controlling the air temperature inside the vehicle, the temperature of the air outlet of the air conditioner is variably controlled based on the measured values from these sensors.

This type of air conditioning control is performed on the assumption that all sensors are operating normally, but for example, if a sensor system such as an internal air sensor that directly affects the cabin environment fails, It is desirable to implement controls to back up this.

As a control means when such a sensor system failure occurs, it is conceivable to use input data from the sensor system before the failure occurs, as shown in Utility Model Application Publication No. 62-178207, for example. ing. In addition, special public service in 1986-
No. 27905 discloses a means for controlling an air conditioner by using other normally operating sensors and predicting the measured value of a failed sensor based on measurement signals from these sensors. There is.

However, when considering how vehicle air conditioners are used, they generally involve rapid temperature changes during transient conditions such as cool-down and warm-up.

Therefore, in such a control state, the measurement signal from the internal air sensor changes over time. Therefore, by using data before the failure or by using measurement signals from other sensors that are approximately constant over time, it is not possible to estimate the true value, especially in transient conditions.

[Problems to be Solved by the Invention] This invention has been made in view of the above points. For example, even if the inside air sensor that measures the temperature inside the vehicle malfunctions, it is possible to control and predict the temperature with high accuracy. The present invention aims to provide an air conditioner for a vehicle that can automatically control the temperature inside the vehicle by setting the temperature.

[Means for Solving the Problems] The air conditioner for a vehicle according to the present invention is configured to set the air conditioner for each control period specified by the measurement signal from the inside air sensor in a state where the inside air sensor is not malfunctioning. A correction value is calculated based on the difference from the previous estimated value, and a new estimated value is calculated using this correction value. If the inside air sensor is out of order, the inside air temperature is calculated based on the set estimated value. is estimated and the blowout temperature is controlled.

[Function] In the air conditioner configured in this way, when the inside air sensor is normal, the temperature inside the vehicle is controlled based on the measurement signal from the inside air sensor, and the next control period is started every control cycle. The vehicle interior temperature at is estimated. If the inside air sensor malfunctions, the vehicle interior temperature at that time is calculated based on this set estimated value, the vehicle interior temperature control is executed based on this temperature, and the next estimated value is calculated. Set. That is, even if the inside air sensor fails, highly accurate temperature control will be performed, and the environment inside the vehicle will be maintained in a good condition.

[Embodiments of the invention] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of an air conditioner installed in a vehicle, in which a blower 12 is driven by a blower motor II.
As a result, either inside air or outside air is sucked in through the suction port switching damper 13 and guided to the evaporator 14. This evaporator 14 is supplied with refrigerant compressed by a compressor 15 driven by an engine mounted on the vehicle, and outputs a cooling output for the air generated by the blower 12 and passing therethrough. On the air flow downstream side of the evaporator 14,
An air mix damper I7 is provided together with the heater core 16, and the air that has passed through the evaporator 14 is transferred to the heater core 1.
6 to the downstream side, or without passing through. That is, the air mix damper 17 is connected to the heater core 1.
By setting the air mix damper 17 so as to cover the surface of the heater core 16, the air flow is guided to the downstream side without passing through the heater core 1B.On the other hand, by covering the portion other than the heater core 16 with the air mix damper 17, all of the air flow is guided downstream without passing through the heater core 1B. It passes through the heater core 16, is heated, and is sent to the downstream side. That is, the air mix damper 17 variably controls the temperature of the air flow sent to the downstream side.

The airflow controlled by the air mix damper 17 is blown out into the passenger compartment 19 of the vehicle via the blowout rod bar 18.

Further, an evaporator sensor 20 for measuring the output air temperature is provided at the outlet of the evaporator 14, and an inside air sensor 21 and a solar radiation sensor 2 are provided inside the vehicle compartment 19.
2 is provided, and an outside air sensor 23 is also set outside the vehicle interior. The measurement signals from these sensors 20 to 23 are sent to a control circuit 2 which is constituted by, for example, a microcomputer.
4 is input. The control circuit 24 receives measurement signals from a water temperature sensor 25 (not shown) that measures the temperature of engine cooling water, and receives operation command signals from a mode switch 26 and a temperature setting switch 27.

The control circuit 24 gives operation commands to servo motors 28 and 29 that drive the air mix damper 17 and the outlet switching damper 18, respectively, and also gives operation commands to the servo motors 28 and 29 that drive the air mix damper 17 and the outlet switching damper 18, respectively.
6. The water valve 30 controls the engine cooling water supplied to the engine. Then, the compressor 15 is controlled in accordance with the air conditioning control contents, and the servo motor 31 that drives the suction port switching damper 13 is further controlled.

FIG. 2 shows the flow of operation of the control circuit 24. First, in step 101, the input signal from the sensor is read, and in step 102, it is determined whether the read measured value is within the set value range or not. , determine whether the sensor system is malfunctioning. If it is determined that the sensor system is not malfunctioning, the process proceeds to the next step 103, where the input signal T from the internal air sensor estimated TI seconds before the control period is input.
The difference between rso and the normal measurement signal Tr of the internal air sensor 21 read in step 101 is determined, and the correction value DELT is determined using the following equation.

DELT-DELTjuKo * (Trso -
Tr)... (1) However, the initial value of the correction value DELT is "0'.

In the next step 104, based on the correction value DELT obtained in step 103 and the measured signal Tr read from the normal sensor 21, the estimated value T rso of the internal air sensor after the control period TI is obtained using the following equation.

Trso = fl *25- (89+DEL
T) XTr 1/ (90+DELT)...
・・・・・・・・・・・・ (2) Constants shown here
1” (89-DELT), (90DELT)
, a combination of these numerical values, and the control period TI seconds, assuming that the value of the correction value DELT is constant, the estimated value T rso changes with the same characteristics as the change in the first-order lag.

Furthermore, when the internal air sensor 21 is normal with respect to the estimated value Trso, the deviation from the actual measured value Tr is fed back to the correction value DELT.
It is possible to perform a corrective operation so that the estimated first-order lag characteristic (time constant) approaches the actual characteristic (time constant).

Here, the constant in equation (1) is an experimental value, and has the meaning of a gain that determines the speed of the correction operation.

In step 105, the target blowout temperature TAO is determined.In step 105, the measurement signal Tr of the inside air sensor 21 (the actual temperature measured by the inside air sensor 21 or the estimated value Trso TI seconds before), the outside air sensor 2
Using the outside air temperature TAM measured in step 2, the measurement signal Ts from the solar radiation sensor 22, and the set temperature Tset set by the temperature setting switch 27 provided on the setting panel, the target air temperature TAO is determined based on the following formula. I begin to seek it.

TAO=Kset XTset -Kr XTr -K
AM XTAM -Ks X Ts + C...
-(3) However, Kset SKr, KAM, Ks
Gain C: Correction Count In the next step 106, each of the air mix dampers 17, the air outlet switching dampers 18, etc. that drive the air mix damper 17, the air outlet switching damper 18, etc. Calculate the control amount of the actuator.

In step 107, the control amount of each actuator determined in this way is output, and in step 108, the step 108 waits for a time of 71 seconds, which is the control cycle.
Return to

If it is determined in step 02 that the sensor is malfunctioning, the process proceeds to step 109. This step 109
Then, the estimated value T is calculated for the measurement signal Tr of the internal air sensor 21.
rso, and this estimated value T rso is used as the measurement signal of the internal air sensor.

In the next step 110, based on the estimated value T rso s correction value DELT estimated 11 seconds before this control period,
Estimated temperature T rs of the measurement value of the inside air sensor after TI seconds.

is determined based on equation (2) above.

In this case, when the inside air sensor 21 is normal, step 1
The error “(Trso −Tr)” obtained in 03 is “
Therefore, if failures occur continuously, the correction value DELT will maintain a constant value.

Figure 3 shows how the temperature inside the vehicle changes due to control using such an estimated operation. There is. The change in the inside air temperature when a disturbance occurs in which the inside air sensor 21 temporarily fails (in this example, for 240 seconds) is shown by solid line A, and the sensor malfunctions or occurs due to disturbance etc. from 60 seconds after the air conditioner is started. death,
This shows a case where the state returns to normal after 240 seconds.

In this figure, a dashed-dotted line B indicates the state of change in the estimated value T rso of the measured value of the inside air sensor 21.

In the characteristics of an actual air conditioner for a vehicle, changes in internal air temperature during cool-down and the like do not strictly correspond to a first-order lag. Therefore, an estimation error occurs as time passes, and after 240 seconds have elapsed, in the example shown in FIG. 3, there is an estimation error of 3.9°C. However, the temporary failure does not make the occupants in the vehicle cabin feel it, and control is possible within a range that maintains the indoor environment in a good condition.

On the other hand, if normal control is continued without estimating the inside air temperature, if the sensor fails, "Tr--
Since the system is controlled using a value such as 6.5 degrees Celsius, for example, warm air may come out during cooling operation, or the air volume may suddenly reach its maximum, causing great discomfort to the occupants. Not only can it cause damage, but it can also cause problems with driving.

Moreover, in the apparatus shown in the example, the inside air temperature was approximated with a first-order lag. This is because calculations can be performed simply, and it has been determined that a first-order approximation is possible when assuming changes in the internal air temperature of the actual machine.

In addition, in the explanation of the example, it is assumed that the change in the internal air temperature is a first-order lag that converges to, for example, 25°C;
It is also effective to set °C as a target indoor air temperature resulting from the set temperature, outside air temperature, amount of solar radiation, etc., and to modify it as appropriate.

[Effects of the Invention] As described above, according to the air conditioner for a vehicle according to the present invention, even if, for example, the inside air sensor fails, the inside air temperature control corresponding to the previous control history can be executed. For example, even if a sensor failure occurs during excessive conditions such as cool-down or warm-up, it is possible to maintain temperature control while maintaining a good environment inside the vehicle, and the air conditioning effect can be improved. It will be held stable.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating an air conditioner for a vehicle according to an embodiment of the present invention, FIG. 2 is a flowchart illustrating the flow of operation of a control circuit configuring the device, and FIG. 3 is a diagram illustrating the internal air temperature. It is a figure showing a control state. 12... Blower, 14... Evaporator, 15...
・Compressor, 16... Heater core, 17... Air mix damper, 19... Vehicle interior, 20... Evaporator sensor, 21... Inside air sensor, 22... Solar radiation sensor, 23... Outside air Sensor, 24... control circuit,
26...Mode switch, 27...Temperature setting switch. Applicant's representative Patent attorney Takehiko Suzue Time (seconds) -

Claims (1)

[Scope of Claims] An inside air sensor set in a vehicle interior; means for measuring an inside air temperature detected by the inside air sensor at each specified control cycle; and whether or not the inside air sensor is operating normally. a correction value based on a difference between a set estimated inside air temperature value and an inside air temperature measured by the inside air sensor when the inside air sensor is determined to be operating normally by the determining means; means for calculating, based on the correction value calculated by the means, means for predicting a new estimated value of the inside air temperature for the next control cycle; and determining that the inside air sensor is not operating normally by the determining means. means for taking in the set inside air temperature estimate value as the inside air temperature in the state where the inside air temperature is set, and means for predicting a new estimated value of the inside air temperature for the next control cycle based on the inside air temperature taken in by this means. An air conditioner for a vehicle, comprising: a target blowout temperature is calculated based on the measured inside air temperature or the taken inside air temperature.