Air conditioner for vehicle

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention processes a plurality of physical quantities related to a heat load including difficult or unmeasurable physical quantities based on modern control theory, and optimally controls air conditioning control elements such as temperature adjusting means, air volume adjusting means, and blowing mode adjusting means. The present invention relates to a vehicle air conditioner that calculates an amount and converges the vehicle interior temperature to a set target temperature.

【0002】

[Conventional technology]

As an air conditioner for a vehicle that uses modern control theory to air-condition the vehicle interior temperature to a target temperature, for example, the one shown in Japanese Patent Application Laid-Open No. 5-50836 is known. This calculates the target value of the physical quantity (vehicle interior temperature and skin temperature) that should be changed over time among the physical quantities related to the heat load required for air conditioning control based on the vehicle interior temperature set value, and is used as the control quantity for the controlled object. A state variable representing the internal state of the dynamic model related to air conditioning is estimated from the vehicle interior temperature, the optimum control constant for following the target value is calculated, and based on the target value, the estimated state variable, and the vehicle interior temperature. The optimum control quantity for the controlled object is determined, thereby ensuring responsiveness and stability in all environments.

【0003】

More specifically, the controller used in this system has the amount of solar radiation Qsun, the outside air temperature Tamb, and the vehicle interior temperature set value Tptc, as shown in the block diagram of FIG. 3 (same as FIG. 2 of the same publication). , The control amount (air mix door opening X, blower drive voltage Vf) for controlling the air conditioning unit 10 is calculated based on the vehicle interior temperature Tinc. Functionally, the standard model 20, the observer 30, and the linear type are calculated. It consists of a compensator 40 and an optimum regulator 50.

【0004】

In the normative model 20, the vehicle interior temperature set value Tptc is changed based on the equation of state shown in Equation 1 in order to change the blowout temperature To and the blowout air volume Ga by the air conditioning unit 10 so as to match the comfort of the occupants. Target vehicle interior temperature Tinc that matches the comfort of the occupants^*And target skin temperature Tf^*And are calculated.

【0005】

[Number 1]

dXr / dt = Ar Xr + Br Tptc Yr = Cr Xr [0006]

Here, Ar, Br, and Cr are coefficient matrices, and Yr = Xr = [Tf.^*, Tinc^*]^TIs.

【0007】

Observer 30 is an estimate of body temperature Tm^S, Estimated vehicle interior temperature Tinc^S, Estimated value of blown air volume Ga^S, Estimated air mix door opening Xmm^SState variable Xo consisting of^S(= [Tm^S, Tinc^S, Ga^S, Xmm^S]^T) Is estimated, and among the estimated state variables, the estimated value of the vehicle body temperature Tm^S, Estimated value of blown air volume Ga^S, And air mix door opening estimate Xmm^SCurrent skin temperature estimate Tf based on^SPredict.

【0008】

Then, in the optimum regulator 50, the evaluation function J shown in Equation 2 is used to calculate the deviation from the target value and the rate of change of the control amount in the system considering the linearization compensation by the linear compensator 40, and the evaluation function. Determine the control amount U of the air conditioning unit 10 that minimizes J.

【0009】

[Number 2]

J = {W1 (ΔTint)²+ W2 (ΔTf)²+ W3 (du1 / dt)²+ W4 (du2 / dt)²} dt [0010]

Here, ΔTint is the target value Tinc of the vehicle interior temperature.^*Deviation from, ΔTf is the target value of skin temperature Tf^*Deviation from, du1 / dt is the rate of change of the command value that determines the blower drive voltage Vf (blowout air volume Ga), and du2 / dt is the rate of change of the command value that determines the air mix door opening X (blowout temperature To). Represented, W1 to W4 are weighting coefficients.

【0011】

And the control amount U (= [u1, u2]^T) Is determined by constructing an expansion system as shown in Equation 3 from the above equation 1 and the conversion function that performs linearization compensation, and is expressed by Equation 4 from the control rule that minimizes the evaluation function J in this expansion system. Determine the control constants (K1, K2, K3).

【0012】

[Number 3]

dE / dt = Ae E + Be dU / dt [0013]

[Number 4]

U = K1 Y + K2 edt + K3 Xr + {U (0) -K1 Y (0) -K3 Xr (0)} [0014]

Where E = [dY / dt, e, dXr / dt]^TAnd Ae and Be are coefficient matrices, e = Yr-Y. U (0), Y (0), and Xr (0) are the initial values of the control command value, output, and state variable, respectively.

【0015】

In such control, as shown in FIG. 4 (same as FIG. 4 of the same publication), the above-mentioned observer is composed of, for example, a same-dimensional state observer, and is previously controlled with respect to the equation of state (formula 5) to be controlled. State variable estimation error εo (= Xo) in the identified estimation model^S-Add feedback to make Xo) converge to zero to form the model of Equation 6.

【0016】

[Number 5]

dXo / dt = Ao Xo + Bo U Yo = Tinc = Co Xo [0017]

[Number 6]

dXo^S/ dt = Ao Xo^S+ Bo U + F (Yo-Yo)^S) Yo^S= Tinc^S= Co Xo^S 【0018】

In such an observer, even if Ao is an unstable matrix, Ao-FCo can be made into a stable matrix by selecting an appropriate gain F, and the estimation error εo (= Xo).^S-Xo) has the advantage of being able to quickly converge to zero.

【0019】

[Problems to be Solved by the Invention]

However, in the above system, since the vehicle interior is approximated by one estimation model by the observer, the accuracy is poor when the air conditioning environment is different on the left, right, or top and bottom of the vehicle interior due to sunlight, etc., and the model accuracy is poor. It cannot be said that it is sufficient. In response to such inconvenience, it is conceivable to independently adjust the temperature of the vehicle interior space up and down, left and right, or front and rear (individual temperature control), but in such a case, the number of control spaces increases, so air conditioning control Even if it is unavoidable to increase the number of elements, if the above system is simply increased by the number of spaces, control will be performed without considering the thermal correlation with other spaces, or a room temperature sensor will be used for each space. The number of room temperature sensors also increases because the room temperature sensor must be provided. Therefore, even when each space is controlled independently, how to individually control each space by associating them with a small number of room temperature sensors, in other words, the physical quantity related to the heat load used for calculating the control amount of the air conditioning control element. The problem is how to estimate in relation to other spaces.

【0020】

Therefore, in the present invention, on the premise of the purpose of the conventional air-conditioning control for ensuring responsiveness and stability under various environments, when the vehicle interior is divided into a plurality of spaces and individually controlled, each space is accurately controlled. The challenge is to provide an air conditioner for vehicles that can control the temperature well.

【0021】

[Means for solving problems]

Therefore, a feature of the present invention is that the control amounts of the plurality of air conditioning control elements are calculated based on the plurality of physical quantities related to the heat load, and the vehicle interior temperature is converged to the set target temperature. In a vehicle air conditioner that optimally controls, the interior of the vehicle is divided into a plurality of control spaces, and a room temperature sensor is provided in at least one of the control spaces. For the space provided with the room temperature sensor, the estimated temperature of the space is provided. The physical quantity is estimated by modifying the dynamic model corresponding to the space according to the difference between the temperature and the space temperature detected by the room temperature sensor. The physical quantity is estimated by modifying the dynamic model corresponding to the space based on the thermal characteristics determined in relation to the space and the modification amount for the dynamic model of the space provided with the room temperature sensor. I have done so.

【0022】

Here, the air conditioning control element means a controllable element of the air conditioning unit such as a temperature adjusting means, an air volume adjusting means, and a blowing mode adjusting means. Therefore, the controlled amount of the air conditioning control element is an air mix door opening degree. (Blowout temperature), blower drive voltage (blowout air volume), damper opening to change the blowout mode, etc. In addition, physical quantities related to heat load include control parameters that can be set by the operation of the occupants, such as the set temperature inside the vehicle, control parameters that can be measured or easily measured, such as the amount of solar radiation, outside air temperature, and vehicle interior temperature, and vehicle body temperature. It includes control parameters that are difficult or impossible to measure, such as the thermal capacity of the passenger compartment and vehicle body.

【0023】

Then, as a basic structure of a vehicle air conditioner that optimally controls an air conditioning control element so that the vehicle interior temperature converges to a set target temperature, a conventionally known structure, that is, a physical quantity related to a heat load, changes with time. Means for generating target values to be made, means for estimating difficult or unmeasurable physical quantities among physical quantities related to heat load based on a dynamic model of a system related to air conditioning, and the target values, estimated physical quantities, and heat. Of the physical quantities related to the load, those equipped with an optimum regulator that determines the optimum control amount of the air conditioning control element that converges the vehicle interior temperature to the target temperature based on the measurable physical quantity may be used.

【0024】

Therefore, in the dynamic model corresponding to the space provided with the room temperature sensor, the difference between the calculated estimated temperature of the space and the space temperature actually detected by the room temperature sensor is taken into consideration. As a known same-dimensional observer, the physical quantity (state variable) representing the internal state of the dynamic model is estimated accurately. On the other hand, for the dynamic model corresponding to the space without the room temperature sensor, sufficient accuracy can be obtained by simply adding the correction amount used for the dynamic model of the space with the room temperature sensor. Therefore, the physical quantity (state variable) representing the internal state is estimated by further considering the thermal characteristics determined in relation to other spaces. As a result, the physical quantity can be estimated accurately in any space.

【0025】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but it is assumed that the vehicle interior space is divided into two spaces, upper and lower, left and right, or front and rear, and each of them is independently temperature-controlled. The other is the second space. Further, as the overall system configuration, various air conditioners using modern control theory (for example, JP-A-5-50836) can be used. Therefore, for convenience, the overall system configuration is JP-A-5-50836. Assuming that the publication is basically the same as that of the publication, the features of the present application will be mainly described below.

【0026】

Further, as an air conditioning unit, even if one air conditioning unit is provided with as many air mix doors as the number corresponding to each space and each space is controlled independently, separate air conditioning corresponding to each space is provided. A unit may be provided.

【0027】

By the way, in this embodiment, the heat balance model of the first space is considered as Equation 7 and the heat balance model of the second space is considered as Equation 8 among the spaces divided into two.

【0028】

[Number 7]

Mr1 dTr1 / dt = α1 (To1-Tr1) -β1 (Tr1-Tb1) + Qs1 Mb1 dTb1 / dt = β1 (Tr1-Tb1) -δ1 (Tb1-Ta) + Qs2 [0029]

[Number 8]

Mr2 dTr2 / dt = α2 (To2-Tr2) -β2 (Tr2-Tb2) + Qs3 Mb2 dTb2 / dt = β2 (Tr2-Tb2) -δ2 (Tb2-Ta) + Qs4 [0030]

The first equation of Equation 7 is a differential equation representing the heat balance model seen in the first space, the second equation is a differential equation representing the heat balance model seen in the vehicle body on the first space side, and the first equation of Equation 8 Is a differential equation that represents the heat balance model seen in the second space, and the second equation is a differential equation that represents the heat balance model seen in the vehicle body on the second space side.

【0031】

Here, Ta represents the outside temperature, To1 is the temperature of the air blown into the first space, Tr1 is the room temperature of the first space detected by the room temperature sensor arranged in the first space, and Tb1 is the side of the first space. Body temperature, Mr1 is the heat capacity of the first space, Mb1 is the heat capacity of the body on the first space side, α1 is the air volume to the first space, β1 is the heat transfer rate from the first space to the body on this space side, δ1 is the first 1 The heat transfer rate from the vehicle body on the space side to the atmosphere, Qs1 represents the amount of heat that directly enters the first space due to solar radiation, and Qs2 represents the amount of heat absorbed by the vehicle body on the first space side due to sunlight. In addition, To2 is the temperature of the air blown into the second space, Tr2 is the room temperature of the second space, Tb2 is the body temperature of the second space, Mr2 is the heat capacity of the second space, and Mb2 is the heat capacity of the body of the second space. α2 is the air volume to the second space, β2 is the heat transfer rate from the second space to the vehicle body on this space side, δ2 is the heat transfer rate from the vehicle body on the second space side to the atmosphere, and Qs3 is to the second space by solar radiation. The amount of heat that directly enters, Qs4, represents the amount of heat absorbed by the vehicle body on the second space side due to sunlight.

【0032】

When the above differential equation is expressed in a matrix, it becomes the equation 9, and when it is rewritten, it becomes the equation of state shown by the equation 10. X1 (= [Tr1, Tb1]^T), X2 (= [Tr2, Tb2]^T) Is a state variable vector, U1 (= [To1, Ta, Qs1, Qs2]^T), U2 (= [To2, Ta, Qs3, Qs4]^T) Is the control input value vector. The estimated value of the state variable of X1 estimated by the estimation model of the first space is Z1 (= [Tr1', Tb1']].^T), And the estimated value of the state variable of X2 estimated by the estimation model of the second space is Z2 (= [Tr2', Tb2']].^T), The estimation model of each space is expressed by the mathematical formula 11.

【0033】

[Number 9]

<img file="JPH09123731A_D0001.tif" />【0034】

[Number 10]

dX1 / dt = A1, X1 + B1, U1 (1) dX2 / dt = A2 X2 + B2 U2 (2) Y1 = Tinc = C1 X1 [0035]

[Number 11]

dZ1 / dt = A1, Z1 + B1, U1 dZ2 / dt = A2 Z2 + B2 U2 Y1'= C1 Z1 [0036]

Y1 (= Tinc) and Y1'(= Tr1') as shown in Fig. 1 in order to converge the estimation error e1 (= X1-Z1) of the state variable to zero for the estimation model of the first space. ) Is fed back to express the observer in the first space as in Equation 12, and the correction amount of the amount of feedback applied to the observer in the first space is added to the estimation model in the second space, and the observer in the second space. Is expressed as Equation 13.

【0037】

[Number 12]

dZ1 / dt = A1, Z1 + B1, U1 + K1 (Y1-Y1') [0038]

[Number 13]

dZ2 / dt = A2 Z2 + B2 U2 + K2 K1 (Y1-Y1') [0039]

Here, K1 is predetermined so that the estimation model of the first space converges as described above, and K2 determines the estimation model of the second space in consideration of the thermal correlation between the first space and the second space. It is a coefficient matrix to be corrected, and is determined as in Equation 14 using, for example, the heat transfer coefficient between the first space and the second space.

【0040】

[Number 14]

<img file="JPH09123731A_D0002.tif" />【0041】

To explain the determination method of K1 and K2 more concretely, in K1, since the estimation error e1 of the state variable is (X1-Z1), equation 15 is obtained from equation 10 (1)-formula 12. ..

【0042】

[Number 15]

dX1 / dt-dZ1 / dt = A1 (X1-Z1) -K1 (Y1-Y1') = A1 (X1-Z1)-K1 C1 (X1-Z1) [0043]

Here, from e = X1-Z1, Equation 15 becomes Equation 16 (1), and this general solution is expressed by Equation 16 (2).

【0044】

[Number 16]

de / dt = (A1-K1 C1) e (1) e = EXP (A1-K1 C1) t (2) [0045]

Therefore, e can be converged by appropriately selecting K1 in which A1-K1 and C1 are negative.

【0046】

On the other hand, in determining K2, first, the observer shown in FIG. 1 will be described in detail as shown in FIG. 2, and will be described based on this. Assuming that the observer model matches the actual system and the estimation error e is due to an error in the control input value (for example, an error due to the outside air temperature), the amount of correction of the observer (= K1a (Tinc-Tr1)) ) Is expressed as Equation 17 (1) when converted to the amount of heat related to the vehicle body on the first space side, and therefore becomes Equation 17 (2).

【0047】

[Number 17]

K1a (Tinc-Tr1') = Tb1' β1 / Mb1 (1) Tb1'= K1a (Tinc-Tr1') Mb1 / β1 (2) [0048]

Now, if the error on the second space side is caused by the same cause as the error on the first space side, the corrected heat quantity in the second space can be calculated as in Equation 18 (1), and therefore K2a. Is as in Equation 18 (2).

【0049】

[Number 18]

Tb1' β2 / Mb2 = K1a (Tinc-Tr1') Mb1 / β1 β2 / Mb2 (1) K2a = Mb1 β2 / β1 / Mb2 (2) [0050]

Similarly, the amount of modification of the observer (= K1b (Tinc-Tr1')) is expressed as in Equation 19 (1), and the amount of correction in this case is Ta' δ2 / Mb2. , K2b becomes like Equation 19 (2).

【0051】

[Number 19]

K1b (Tinc-Tr1') = Ta' δ1 / Mb1 (1) K2b = Mb1 δ2 / δ1 / Mb2 (2) [0052]

Then, depending on how the first space and the second space are divided, for example, Mb1 Mb2 may be obtained. In this case, K2 in FIG. 1 is determined as in the above-mentioned mathematical formula 14.

【0053】

Therefore, for the dynamic model corresponding to the first space of the present invention, the correction is made based on the deviation between the measured temperature (detected value) detected by the room temperature sensor provided in the first space and the estimated temperature thereof. It has the same configuration as the conventional one, and the physical quantities (room temperature Tr1 in the first space and body temperature Tb1 on the first space side) representing the dynamic internal state are estimated accurately. On the other hand, in the dynamic model corresponding to the second space, if the correction amount is the same as the correction amount for the dynamic model in the first space, there is a problem in model accuracy. The coefficient matrix representing the thermal characteristics determined in relation to is multiplied by the amount of correction for the dynamic model in the first space, and the multiplied value is used to correct the dynamic model in the second space. The physical quantities that represent the internal state of the dynamic model in two spaces (room temperature Tr2 in the second space and vehicle body temperature Tb2 on the second space side) can also be estimated accurately.

【0054】

[Effect of the invention]

As described above, according to the present invention, the vehicle interior is divided into a plurality of control spaces, and the air conditioning control elements are optimally controlled based on the dynamic model of the system related to the air conditioning of each space to control the temperature of each space independently. In doing so, at least one dynamic model is modified based on the deviation between the spatial temperature corresponding to that model and the estimated spatial temperature, and for the other dynamic models, the corresponding spatial temperature is modified. Since the modification is made in consideration of the thermal characteristics determined in relation to other spaces, the estimation accuracy of physical quantities can be improved in each dynamic model, and in each divided interior space. The temperature control can be controlled accurately. Further, since a room temperature sensor is not required for each space, even when each space is independently temperature-controlled, it is possible to handle with a small number of room temperature sensors.

[Simple explanation of drawings]

[Figure 1]

FIG. 1 is a block diagram showing an example of an observer used in the vehicle air conditioner according to the present invention.

[Figure 2]

FIG. 2 is a block diagram showing the observer in more detail.

[Fig. 3]

FIG. 3 is a functional block diagram showing the entire system configuration of the conventional vehicle air conditioner.

[Fig. 4]

FIG. 4 is a block diagram showing an example of a conventional observer.

[Explanation of symbols]

10 Air conditioning unit 20 normative model 30 Observer 40 linear compensator 50 Optimal regulator