JP4706671B2 - Solenoid valve control device - Google Patents

Description

  The present invention relates to a control device for a solenoid valve that controls a current flowing through the solenoid valve.

  Conventionally, an electromagnetic pressure control valve used to control the discharge capacity of a variable capacity compressor is known. This type of electromagnetic pressure control valve is duty-controlled so that the amount of current supplied to the electromagnetic coil approaches the target control current In, and the duty control is realized by a control device (for example, Patent Document 1). reference).

The technique described in Patent Document 1 detects an actual current flowing through an electromagnetic coil and a power supply voltage applied to the electromagnetic coil at a plurality of timings, respectively, and based on each detected current and each power supply voltage. A plurality of impedances are calculated, an average value of these impedances is calculated, and the duty ratio is corrected by the product of the ratio of the control current to the power supply voltage and the average impedance value.
JP 2006-250203 A

  However, since the actual impedance of the electromagnetic coil changes depending on the temperature of the electromagnetic coil, as described above, even if the average value of the impedance is calculated, this average value is different from the actual impedance. For this reason, even if the current flowing through the electromagnetic coil is adjusted using the duty ratio corrected using the average value of the impedance, the actual current flowing through the electromagnetic coil cannot be brought close to the control current In with high accuracy. The degree of opening cannot be controlled with high accuracy.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a control device for an electromagnetic valve capable of accurately adjusting an energization current flowing through an electromagnetic coil so as to approach a target control current.

  In order to achieve the above object, the invention according to claim 1 controls the impedance estimating means (S190) for estimating the impedance of the electromagnetic coil (32) of the electromagnetic valve (23) and the current flowing through the electromagnetic coil (32). The duty ratio calculating means (S200) for calculating the duty ratio for performing the calculation based on the impedance estimated by the impedance estimating means (S190), and the ratio of the voltage application time per unit time is calculated by the duty ratio calculating means. And an applied voltage adjusting means (41) for applying a voltage to the electromagnetic coil so as to obtain a duty ratio, wherein the impedance estimating means (S190) detects the temperature change of the electromagnetic coil (32). Estimating impedance using parameters set to change with To.

  According to the first aspect of the present invention, the duty ratio is calculated based on the estimated impedance using the parameter set so as to change with the temperature change of the electromagnetic coil (32), and the unit time per unit time is calculated. Since the voltage application time is adjusted so that the voltage is applied to the electromagnetic coil (32) so that the ratio of the voltage application time becomes the duty ratio, the energization current can be brought close to the target value (In (n)) with high accuracy.

  However, the “ratio of voltage application time per unit time” is information on the ratio of “time during which voltage is applied to the electromagnetic coil” in the unit time.

Further, an invention according to claim 1, impedance estimating means (S190) is repeated, which estimates the impedance, the duty ratio calculating means (S200), the impedance estimating means (S190) to estimate the impedance The duty ratio is calculated every time based on the estimated impedance, and every time the duty ratio calculating means (S200) calculates the duty ratio, the applied voltage adjusting means (41) is calculated based on the calculated duty ratio. ) Adjusts the ratio of the voltage application time per unit time to the electromagnetic coil (32).

According to the first aspect of the present invention, since the duty ratio is calculated repeatedly, even if the temperature of the electromagnetic coil (32) changes with time, the latest duty ratio among the repeatedly calculated duty ratios is obtained. In addition, since the voltage is applied to the electromagnetic coil (32), the energization current can be brought close to the target value (In (n)) with high accuracy.

The invention of claim 1, prior SL includes a target value of the current flowing through the solenoid valve (32) to (an In (n)) current target value setting means for setting a (S100),
The duty ratio calculation means (S200) calculates the duty ratio (DT (n)) so that the current flowing through the electromagnetic coil (32) approaches the target value.
The previous current for determining whether or not the target value (In (n)) has been set by the current target value setting means (S100) when the duty ratio calculation means (S200) previously calculated the duty ratio. Target value setting presence / absence determination (S160),
When the previous current target value setting presence / absence determination (S160) determines that the target value has been set by the current target value setting means (S100) when the duty ratio calculation means has previously calculated the duty ratio. Is a first setting means (S170) for setting the parameter so that the impedance is increased by assuming that the temperature of the electromagnetic coil (32) is high at present.
When the previous current target value setting presence / absence determination (S160) determines that the target value has not been set by the current target value setting means (S100) when the duty ratio calculation means previously calculated the duty ratio Compared with the case where the previous current target value setting presence / absence determination (S160) determines that the target value has been set by the current target value setting means (S100), the temperature of the electromagnetic coil is currently lower. Second setting means (S180) for setting the parameter so that the impedance is reduced as it is in a state,
The impedance estimation means (S190) estimates the impedance using a parameter set in one of the first and second setting means.

According to the first aspect of the present invention, when the duty ratio calculation unit (S200) previously calculated the duty ratio, it is determined whether or not the target value is set by the current target value setting unit (S100). In order to determine whether or not the current temperature of the electromagnetic coil is high by the previous current target value setting presence / absence determination (S160), only the temperature detection means for directly detecting the temperature of the electromagnetic coil such as a temperature sensor is used. Compared to the case where it is used, it is possible to quickly determine whether or not the temperature of the electromagnetic coil is high.

In the first aspect of the invention, it goes without saying that temperature detecting means for directly detecting the temperature of the electromagnetic coil may be provided.

Specifically, as in the invention described in claim 2 , in the invention described in claim 1 , the duty ratio calculation means (S200) determines the duty ratio (DT (n)) as the current of the current. It is calculated so as to approach the target duty ratio (MDT (n)) indicating the target value,
In the previous current target value setting presence / absence determination (S160), when the duty ratio calculation means (S200) has previously calculated the duty ratio, the current target value setting means (S100) sets the target value (In (n)). ) May be determined to determine whether the target duty ratio (MDT (n)) has been set.

Further, in the invention according to claim 2 , in the invention according to claim 1 , voltage detecting means (S110, 43) for repeatedly detecting the voltage value applied to the electromagnetic coil (32), and the electromagnetic coil (32). Current detection means (S120, 42) for repeatedly detecting the current value flowing through the current ratio, the duty ratio (DT (n)) calculated by the previous duty ratio calculation means, and the voltage detected this time by the voltage detection means (S110, 43) Based on the value and the current value detected this time by the current detection means (S120, 42), the impedance calculation means (S150) calculates the actual impedance when the duty ratio is calculated by the previous duty ratio calculation means (S200). The impedance estimation means (S190) is provided by the impedance calculation means (150). By correcting by the actual impedance of the previously calculated parameters, and estimates the current impedance.

According to the third aspect of the present invention, the previous actual impedance is calculated based on the previously calculated duty ratio, the current voltage value, and the current value, and the calculated previous impedance is set as a parameter. Thus, the current impedance is obtained by correction, so that the current impedance can be estimated close to the actual impedance.

  In addition, the code | symbol in the bracket | parenthesis of each means described in a claim and this column shows the correspondence with the specific means as described in embodiment mentioned later.

  FIG. 1 is an overall configuration diagram of an embodiment of the present invention, and shows a refrigeration cycle apparatus applied to a vehicle air conditioner. The refrigeration cycle 1 includes a compressor 2 that sucks, compresses, and discharges refrigerant. The high-temperature and high-pressure superheated gas refrigerant discharged from the compressor 2 flows into the condenser 3, where the refrigerant is cooled and condensed by exchanging heat with outside air blown from a cooling fan (not shown).

  The refrigerant condensed in the condenser 3 then flows into a liquid receiver (gas-liquid separator) 4 where the gas-liquid refrigerant is separated inside the liquid receiver 4, and surplus refrigerant (liquid refrigerant in the refrigeration cycle 1 is separated). ) Is stored in the liquid receiver 4. The liquid refrigerant from the liquid receiver 4 is decompressed to a low pressure by an expansion valve (decompression means) 5 to be in a gas-liquid two-phase state. The low-pressure refrigerant from the expansion valve 5 flows into the evaporator 6. The evaporator 6 is installed in the air conditioning duct 7 of the vehicle air conditioner, and the low-pressure refrigerant flowing into the evaporator 6 absorbs heat from the air in the air conditioning duct 7 and evaporates.

  The expansion valve 5 is a temperature type expansion valve having a temperature sensing cylinder 5a for sensing the temperature of the outlet refrigerant of the evaporator 6, and the valve opening degree (refrigerant) is maintained so as to maintain the degree of superheat of the outlet refrigerant of the evaporator 6 at a predetermined value. (Flow rate) is adjusted. The above-described cycle components (1 to 6) are respectively coupled by a refrigerant pipe 8d. The compressor 2 is driven by a vehicle travel engine 11 via an electromagnetic clutch 9, a belt 10 and the like.

  The air conditioning duct 7 is provided with a blower 12, and air in the vehicle interior (inside air) or air outside the vehicle interior (outside air) sucked from a known inside / outside air switching box (not shown) is sent by the air blower 12. The inside is blown. This blown air passes through the evaporator 6 and then passes through the heater unit 8a and is blown out from the blowout opening into the vehicle interior. In the air conditioning duct 7, an evaporator outlet temperature sensor 13 composed of a thermistor for detecting the temperature of the outlet air immediately after passing through the evaporator 6 is provided at a position immediately after the air outlet of the evaporator 6.

  The heater unit 8a is a well-known hot water heater core that heats the cold air that has passed through the evaporator 6, and a bypass passage that bypasses the heater unit 8a and flows the cold air that has passed through the evaporator 6 on the side of the heater unit 8a. 8c is provided. An air mix door 8b is provided on the air upstream side of the bypass passage 8c. The air mix door 8b adjusts the temperature of the air blown into the vehicle interior by adjusting the ratio of the amount of air flowing through the bypass passage 8c and the amount of air flowing through the heater unit 8a by adjusting the opening. The air mix door 8b is driven by a servo motor (not shown).

  Next, the electrical configuration of the present embodiment will be described.

  The electronic control device 14 includes peripheral circuits such as a CPU 40, a valve drive circuit 41, a current measurement circuit 42, and a power supply voltage detection circuit 43.

  The valve drive circuit 41 is an adjustment unit that adjusts the energization amount of the electromagnetic coil 32 by duty-controlling the power supply voltage applied to the electromagnetic coil 32 with the duty ratio DT as a command value from the CPU 40.

  The current measurement circuit 42 is a current detection unit that detects an actual current i flowing through the electromagnetic coil 32. The power supply voltage detection circuit 43 is voltage detection means for detecting the power supply voltage v of the in-vehicle battery 43 as a power supply. The detected current i and voltage v are input to the CPU 40.

  The electromagnetic clutch 9 of the compressor 2 described above is connected to the electronic control device 14, and when the electromagnetic clutch 9 is energized based on a control signal from the electronic control device 14, the electromagnetic clutch 9 is in a connected state. Thus, the power of the vehicle engine 11 is transmitted to the compressor 2, and the compressor 2 enters an operating state. On the contrary, when the energization of the electromagnetic clutch 9 is interrupted, the electromagnetic clutch 9 is disengaged and the compressor 2 stops.

  An electronic control device for engine control (hereinafter referred to as engine ECU 50), an air conditioner switch (referred to as A / C switch in the figure) 51, and a compressor control switch 52 are connected to the electronic control device.

  The electronic control unit 14 communicates with the engine control electronic control unit. The engine ECU 50 is an electronic control device that controls the vehicle engine 11. The air conditioner switch 51 is turned on / off by an occupant (user) and outputs a signal for instructing start / stop of the operation of the vehicle air conditioner. The compressor control switch 52 is turned on by an occupant (user) and outputs a signal for instructing the maximum capacity of the compressor 2.

  Next, specific structures of the compressor 2 and the electromagnetic clutch 9 will be described with reference to FIG.

  The compressor 2 is a well-known wobble type. The power of the vehicle engine 11 is transmitted to the rotating shaft 15 of the compressor 2 via the electromagnetic clutch 9, and the rotating shaft 15 rotates. A swash plate 16 is connected to the rotary shaft 15 so as to be integrally rotatable. When the swash plate 16 rotates, the piston 17 reciprocates in the axial direction.

  Further, the discharge capacity of the compressor 2 (hereinafter simply referred to as “capacity”) is varied by changing the stroke of the piston 17 by changing the inclination angle of the swash plate 16. Therefore, the swash plate 16 is connected to the rotary shaft 15 so as to be swingable. Specifically, the swash plate 16 is supported by the spherical support portion 18 so as to be swingable. The inclination angle of the swash plate 16 is the pressure acting on the front and rear of the piston 17, that is, the pressure in the crank chamber 19 acting on the back surface of the piston 17, that is, the control pressure Pc, and the pressure in the cylinder 20 where the piston 17 reciprocates. It changes depending on the balance with (discharge pressure Pd and suction pressure Ps). Therefore, the inclination angle of the swash plate 16 can be changed by adjusting the control pressure Pc in the crank chamber 19.

  The gas refrigerant compressed by the cylinder 20 of the compressor 2 is discharged into the discharge chamber 21, and the gas refrigerant is discharged from here through the discharge port (not shown) to the condenser 3 side in FIG. 1. The refrigerant is sucked into the cylinder 20 of the compressor 2 through the suction chamber 22. The suction chamber 22 communicates with the refrigerant outlet side of the evaporator 6 in FIG. 1 through a suction port 22a. The above-described pressure (control pressure) Pc of the crank chamber 19 is changed by an electromagnetic pressure control device 23 as an electromagnetic valve using the refrigerant discharge pressure Pd of the discharge chamber 21 and the refrigerant suction pressure Ps of the suction chamber 22. It is supposed to let you.

  The electromagnetic pressure control device 23 includes a discharge pressure chamber 24 communicating with the discharge chamber 21, a suction pressure chamber 25 communicating with the suction chamber 22, and a control pressure chamber 26 communicating with the crank chamber 19. It has been. The discharge pressure chamber 24 communicates with the control pressure chamber 26 via a variable throttle 28 whose opening degree is adjusted by a valve body 27. In the present example, the valve element 27 and the variable throttle 28 constitute a variable throttle mechanism. The suction pressure chamber 25 communicates with the control pressure chamber 26 via a fixed throttle 29. The communication relationship between these rooms is shown in FIGS.

  Further, a bellows (pressure responsive mechanism) 30 made of an expandable / contractible material is disposed inside the suction pressure chamber 25, and a predetermined internal pressure Pb is set in the bellows 30 in advance. The bellows 30 expands and contracts due to a change in the suction pressure Ps with respect to Pb. The valve element 27 is displaced via the rod 31 by the expansion and contraction of the bellows 30. The bellows 30 and the valve body 27 are also acted on by the electromagnetic force of the electromagnetic mechanism.

  In other words, the electromagnetic mechanism of this example includes an electromagnetic coil 32, a fixed magnetic pole member 33, and a movable magnetic pole member (plunger) that is attracted in the direction of the fixed magnetic pole member 33 (the direction in which the bellows 30 extends) by the electromagnetic force of the electromagnetic coil 32. 34 and a coil spring 35 that applies a spring force to the movable magnetic pole member 34. A rod 36 is connected to the central portion of the movable magnetic pole member 34. The rod 36, the valve body 27, and the rod 31 are connected together and displaced together.

  FIGS. 3 and 4 are schematic views for explaining the operation of the electromagnetic pressure control device 23. The arrangement state of each part of the electromagnetic pressure control device 23 is different from that in FIG. 2 for simplification of illustration. FIG. 3 shows a state where the capacity of the compressor 2 is increased. When the suction pressure Ps rises above the internal pressure Pb of the bellows 30 due to an increase in the cooling load, the bellows 30 contracts. 3A, the valve body 27 is displaced in the same direction and the opening degree of the variable throttle 28 is decreased. Accordingly, the pressure loss between the discharge pressure chamber 24 and the control pressure chamber 26 increases, and the control pressure Pc in the control pressure chamber 26 decreases.

  As the control pressure Pc decreases, the pressure in the crank chamber 19 decreases and the back pressure of the piston 17 decreases. Therefore, as shown in the left direction of the arrow in FIG. The inclination angle θ of 16 increases. As a result, the stroke of the piston 17 increases and the capacity of the compressor 2 increases. As a result, the cycle circulation refrigerant flow rate increases and the cooling capacity increases, so that the suction pressure Ps gradually decreases.

  Then, when the suction pressure Ps is decreased below the internal pressure Pb of the bellows 30, the bellows 30 expands, so that the rods 31 and 36 move in the right direction of the arrow in FIG. Displacement in the same direction increases the opening of the variable throttle 28. Therefore, the pressure loss between the discharge pressure chamber 24 and the control pressure chamber 26 decreases, and the control pressure Pc in the control pressure chamber 26 increases.

  When the pressure in the crank chamber 19 increases due to the increase in the control pressure Pc, the swash plate 16 stands as shown in the right direction of the arrow in FIG. 4B, and the inclination angle θ of the swash plate 16 decreases. , The capacity of the compressor 2 is reduced. As a result, the cycle circulation refrigerant flow rate decreases and the cooling capacity decreases, so the suction pressure Ps gradually increases.

  As described above, the bellows 30 expands and contracts in response to the change in the suction pressure Ps so that the capacity of the compressor 2 is continuously variably controlled by adjusting the control pressure Pc. The set pressure of the suction pressure Ps by the internal pressure Pb is varied. The direction of the electromagnetic force of the electromagnetic coil 32 is a direction in which the bellows 30 extends, and therefore, the electromagnetic force of the electromagnetic coil 32 acts on the valve body 27 in the direction of increasing the opening degree of the variable throttle 28.

  On the other hand, since the electromagnetic force of the electromagnetic coil 32 is proportional to the control current In flowing through the electromagnetic coil 32, the control pressure Pc is increased by increasing the opening of the variable throttle 28 as the control current In increases. Reduce compressor capacity. When the compressor capacity decreases, the suction pressure Ps increases.

  That is, the control current In determines the set value of the suction pressure Ps that is the target value of the actual suction pressure Ps. Therefore, as shown in FIG. 5, the set pressure of the suction pressure Ps increases as the control current In increases.

  Thereby, the cooling capacity of the evaporator 8 can be controlled by increasing or decreasing the discharge capacity of the compressor 2 and consequently the flow rate of the discharged refrigerant by increasing or decreasing the control current In to increase or decrease the actual suction pressure Ps. For this reason, by adjusting the actual energization current flowing through the electromagnetic coil 32 so as to be close to the target control current In, the suction pressure Ps and thus the evaporator blown air temperature is adjusted.

  Next, in this embodiment, the adjustment process of the energization current by the electronic control unit 14 will be described with reference to FIG.

  In the adjustment process of the energization current, the impedance of the electromagnetic coil 32 of the electromagnetic valve 23 is estimated, the duty ratio for controlling the current flowing through the electromagnetic coil 32 is calculated based on the impedance, and the ratio of the voltage application time per unit time A voltage is applied to the electromagnetic coil 32 so that becomes a duty ratio.

  Here, the “ratio of voltage application time per unit time” is information on the ratio of the “time during which voltage is applied to the electromagnetic coil 32” in the unit time. As the ratio increases, the current value flowing through the electromagnetic coil 32 increases, and as the ratio decreases, the current value flowing through the electromagnetic coil 32 decreases.

  Hereinafter, a specific example of the adjustment process of the energization current by the CPU 40 will be described with reference to the flowchart of FIG.

  First, when the ignition switch of the vehicle engine 11 is turned on, power is supplied to the CPU 40, and the CPU 40 executes the computer program according to the flowchart of FIG. The computer program is repeatedly executed every fixed period Ts. The certain period Ts indicates the execution cycle of the computer program.

  First, in step S90, it is determined whether or not it is necessary to set the control current In (n) according to the air conditioning requirements. Here, the control current In (n) is a target value of the current flowing through the electromagnetic coil 32.

  For example, in step S90, it is determined whether or not the compressor control switch 52 is turned on. The compressor control switch 52 is a switch that outputs a command for setting the maximum capacity of the compressor 2 of the compressor 2 when being turned on by a passenger. For this reason, when the compressor control switch 52 is turned on, it is determined that the command is issued to set the maximum capacity of the compressor capacity of the compressor 2.

  As described above, the compressor 2 of the present embodiment increases the compressor capacity as the control current In decreases. Therefore, when the maximum capacity of the compressor capacity of the compressor 2 is set, it is necessary to set the control current In = 0. That is, when the compressor control switch 52 is turned on, the control current In (n) should not be set, and NO is determined in step S90. In this case, the control current In is not set and In = 0 is set (step S95).

  On the other hand, when the compressor control switch 52 is off, there is no command to set the maximum capacity of the compressor 2 of the compressor 2, and therefore, in step S90, the control current In according to the air conditioning requirements can be set. It is determined as YES because it is necessary. In this case, the control current In (n) (> 0) is set (step S100). Here, setting the control current In (n) (step S100) means setting the target duty ratio MDT (n), and not setting the control current In (n) (step S100). S95) means that the target duty ratio MDT (n) is not set. The target duty ratio MDT (n) is a duty ratio indicating the control current In (n), and is information identified on a one-to-one basis with the control current In (n).

  The control current In is determined according to the target evaporator blowing temperature TEO calculated by a known air conditioning control method and the detected temperature TE by the actual evaporator blowing temperature sensor 13, and the control current In The characteristic (suction pressure Ps−control current In) shown in FIG. 5 is obtained. Note that n in parentheses indicates the number of executions of the computer program.

  In the next step S110, the power supply voltage v (n) detected by the power supply voltage detection circuit 43 is read. Further, in the next step S120, the current i (n) detected by the current measuring circuit 42 is read.

  In the next step S130, it is determined whether or not the execution of the computer program is the first execution after the power is supplied to the CPU 40.

  Here, if the computer program is executed for the first time after power is supplied to the CPU 40, the determination is YES. Accordingly, the process proceeds to step S140, and the impedance R (n) of the electromagnetic coil 32 is set to the initial value R0 (R (n) = R0).

  Here, R (n) is the impedance of the electromagnetic coil 32 used for adjusting the energization current as will be described later.

  In the next step S200, the current duty ratio DT (n) is calculated by substituting the control current In (n), the detected power supply voltage v (n) and the impedance R (n) (= R0) into the following equation 1. To do.

DT (n) = {In (n) × R (n)} / v (n)}.
In the next step S210, DT (n) calculated in step S200 described above is output to the valve drive circuit 41. Accordingly, the valve drive circuit 41 applies a voltage to the electromagnetic coil 32 so that the ratio of the voltage application time per unit time becomes the duty ratio DT (n). Thereby, the valve drive circuit 41 adjusts the energization amount of the electromagnetic coil 32 using the duty ratio DT (n).

  Thereafter, the process returns to step S90, and it is determined whether or not it is necessary to set the control current In (n + 1) according to the air conditioning requirements, as described above. If it is determined YES in step S90 because it is necessary to set the control current In (n + 1), the control current In (n + 1) is set (step S100). If NO is determined in step S90 because it is not necessary to set the control current In (n + 1), the control current In (n + 1) = 0 is set (step S95).

  Thereafter, in step S110, the power supply voltage v (n + 1) is read. Further, in the next step S120, the current i (n + 1) is read.

  In the next step S130, is the execution of the computer program executed for the first time after power is supplied to the CPU 40 (that is, after the ignition switch is turned on and power is supplied to the electronic control unit 40)? Determine whether or not.

  Here, when the computer program is executed for the second time after power is supplied to the CPU 40, the determination is NO and the process proceeds to step S150.

  At this time, the previous actual impedance R (n) when the duty ratio DT (n) is calculated by the process of the previous step S200 is calculated using Equation 2. That is, the duty ratio DT (n) calculated in the previous step S200, the power supply voltage v (n + 1) detected this time, and the current i (n + 1) detected this time are substituted into Equation 2, and the previous actual impedance R (n) is calculated.

R (n) = {v (n + 1) × DT (n)} / i (n + 1)...
In the next step 160, it is determined whether or not the target duty ratio MDT (n) has been set when the duty ratio DT (n) is calculated by the process of the previous step S200. Specifically, it is determined whether or not the control current In (> 0) has been set when the duty ratio DT (n) is calculated by the process of the previous step S200. Thus, it is determined whether or not the current temperature of the electromagnetic coil 32 is high.

  Here, if the control current In was set in step S100 when the duty ratio DT (n) was calculated by the previous processing in step S200, it is assumed that the target duty ratio MDT (n) was set. In step 160, the determination is YES. At this time, assuming that the current temperature of the electromagnetic coil 32 is high, the first time constant a is determined as the time constant τ (step S170).

  On the other hand, if the control current In was not set in step S100 when the duty ratio DT (n) was calculated by the previous processing in step S200 (control current In = 0), the target duty ratio MDT (n ) Is not set, NO is determined in step 160. In this case, the second time constant b is determined as the time constant τ for determining the impedance, assuming that the current temperature of the electromagnetic coil 32 is lower than that in the case where YES is determined in step 160 described above (step S180). ).

  Here, the first time constant a and the second time constant b determine the impedance of the electromagnetic coil 32, respectively, and the first time constant a is smaller than the second time constant b. It is set (a <b).

  Thus, by determining whether or not the current temperature of the electromagnetic coil 32 is high, the time constant τ corresponding to the temperature change of the electromagnetic coil 32 can be determined by determining the time constant τ. it can.

  In the next step S190, the time constant τ determined in any of the above-described steps S170 and S180, the above-described period Ts, and the previous impedance R (n) obtained in the above-described step S150 are expressed by the following Equation 3. Substituting and estimating the current impedance R (n + 1). γ is a constant. The period Ts is an execution period of the computer program.

R (n + 1) = (((τ / Ts) −1) × R (n) + γ) / (τ / Ts) (3)
Here, in estimating the current impedance R (n + 1), the reason for using the previous impedance R (n) obtained in step S150 described above instead of the impedance R (n) obtained in the previous step S190 is used. Is as follows.

  That is, the previous impedance R (n) obtained in step S150 is calculated using the duty ratio DT (n), the current power supply voltage v (n + 1), and the current current i (n + 1). For this reason, the previous impedance R (n) obtained in step S150 described above is closer to the actual impedance than the impedance R (n) obtained in previous step S190.

  In the next step S200, the current duty ratio DT (n + 1) is calculated by substituting the control current In (n + 1), the detected power supply voltage v (n + 1) and the impedance R (n + 1) into the following equation 4.

DT (n + 1) = {In (n + 1) × R (n + 1)} / v (n + 1)} (4)
In the next step S210, DT (n + 1) determined in step S200 described above is output to the valve drive circuit 41. Accordingly, the valve drive circuit 41 applies a voltage to the electromagnetic coil 32 so that the ratio of the voltage application time per unit time becomes the duty ratio DT (n + 1). Thereby, the valve drive circuit 41 adjusts the energization amount of the electromagnetic coil 32 using the duty ratio DT (n + 1).

  Thereafter, the process returns to step 90, and similarly to the above, step S100 (or step S95), step S110, step S110, step S120, step S130, step S150, step S160, step S170 (or step S180), step S190, step S200 and step S210 are repeated.

  Accordingly, a time constant τ corresponding to the temperature state of the electromagnetic coil 32 is determined. Then, impedances R (n + 1), R (n + 2), R (n + 3), R (n + 4),... Are sequentially estimated based on this time constant τ. Duty ratios DT (n + 2), DT (n + 2), DT (n + 3), DT (n + 4)... Are calculated for each impedance estimation. Each time the duty is calculated, the valve drive circuit 41 adjusts the energization amount of the electromagnetic coil 32 using the duty ratio.

  According to the present embodiment described above, it is determined whether or not the target duty ratio MDT (n) has been set when the duty ratio DT (n) is calculated by the process of the previous step S200. That is, it is determined whether or not the control current In (> 0) has been set when the duty ratio DT (n) is calculated by the previous processing of step S200. By this determination, it is determined whether or not the current temperature of the electromagnetic coil 32 is high.

  Along with this, the time constant τ, impedance, and duty ratio corresponding to the current temperature of the electromagnetic coil 32 are calculated. And since the energization current which flows into electromagnetic coil 32 is adjusted using such a duty ratio, the energization current which flows into electromagnetic coil 32 irrespective of the temperature fluctuation of electromagnetic coil 32 in electromagnetic pressure control device 23 as an electromagnetic valve Can be accurately approximated to the control current In as the target value. Thereby, the capacity control of the compressor capacity, the suction pressure Ps, and the evaporator blowout air temperature can be adjusted well.

  In the present embodiment, when the duty ratio DT (n) is calculated in the previous step S200 in step S200, it is determined whether or not the target duty ratio MDT (n) has been set. In order to determine whether or not the temperature of the electromagnetic coil 32 is high, the temperature of the electromagnetic coil can be more quickly compared to the case where only the temperature detecting means for directly detecting the temperature of the electromagnetic coil such as a temperature sensor is used. It is possible to determine whether the state is high.

  Needless to say, in the present embodiment, a temperature detecting means for directly detecting the temperature of the electromagnetic coil 32 may be provided.

(Second Embodiment)
In the first embodiment described above, in the compressor 2, as the control current In increases, the opening of the variable throttle 28 is increased, the control pressure Pc is increased, and the compressor capacity is decreased. In the second embodiment, instead of this, in the compressor 2, as the control current In increases, the opening of the variable throttle 28 is decreased to decrease the control pressure Pc, and the compressor Use one that increases capacity. In this case, when the compressor capacity increases, the suction pressure Ps decreases. Therefore, as shown in FIG. 7, the set pressure of the suction pressure Ps decreases as the control current In increases.

  In the present embodiment, the CPU 40 of the electronic control device 14 executes an energization current adjustment process according to the flowchart of FIG. Below, the adjustment process of the conduction current of this embodiment is demonstrated. The energization current adjustment process of the present embodiment is the same process as that of the first embodiment except for the process of step S90, and therefore the description other than the process of step S90 is simplified.

First, in step S90, if it is at least one of the following (1) and (2), it is determined as NO that the control current In should not be set, the process proceeds to step S95, and the control current is In is not set and In = 0.
(1) The electronic control unit 14 receives a command for reducing the capacity of the compressor 2 from the engine ECU 50. The "compressor 2 capacity reduction command" is for the engine ECU 50 to reduce the capacity of the compressor 2 because the engine 11 gives priority to driving the drive wheels of the vehicle and lowers the torque required to drive the compressor 2. It is a command to do.
(2) In the case where the air conditioner switch 51 is in an off state and the vehicle air conditioner is instructed to stop.

  On the other hand, when the electronic control unit 14 has not received the capacity reduction command from the engine ECU 50 and the air conditioner switch 51 is in the on state, it is determined as YES in step S90 because it is necessary to set the control current In. . At this time, the control current In (n + 1) is set (step S100).

  Thereafter, in step S110, the power supply voltage v (n) is read. In step S120, the current i (n) is read.

  In the next step S130, is the execution of the computer program executed for the first time after power is supplied to the CPU 40 (that is, after the ignition switch is turned on and power is supplied to the electronic control unit 40)? Determine whether or not.

  Here, if the execution of the computer program is the “n + 1” (> 2) th execution after the power is supplied to the CPU 40, it is determined as NO and the process proceeds to step S150.

  At this time, the previous actual impedance R (n) when the duty ratio DT (n) is calculated by the previous (ie, n-th) step S200 is calculated.

  In the next step 160, it is determined whether or not the target duty ratio MDT (n) has been set when the duty ratio DT (n) has been calculated in the previous (ie, nth) step S200.

  When the duty ratio DT (n) is calculated by the previous processing of step S200, if the control current In is set in step S100, the target duty ratio MDT (n) is set and the step At 160, the determination is YES. At this time, assuming that the current temperature of the electromagnetic coil 32 is high, the first time constant a is set as the time constant τ (step S170).

  On the other hand, when the duty ratio DT (n) is calculated by the process of the previous step S200, if the control current In = 0 is set in step S95, the target duty ratio MDT (n) is not set, and the step NO is determined at 160. In this case, the second time constant b is determined as the time constant τ for determining the impedance, assuming that the current temperature of the electromagnetic coil 32 is lower than that in the case where YES is determined in step 160 described above (step S180). ).

  In the next step S190, the time constant τ determined in any of the above-described steps S170 and S180, the above-described period Ts, and the previous impedance R (n) obtained in the above-described step S150 are expressed by the above-described equation 3. Substituting and estimating the current impedance R (n + 1).

  In the next step S200, the current duty ratio DT (n + 1) is calculated by substituting the control current In (n + 1), the detected power supply voltage v (n + 1), and the impedance R (n + 1) into the above-described equation 4.

  In the next step S210, DT (n + 1) determined in step S200 described above is output to the valve drive circuit 41. Accordingly, the valve drive circuit 41 applies a voltage to the electromagnetic coil 32 so that the ratio of the voltage application time per unit time becomes the duty ratio DT (n + 1).

  According to the present embodiment described above, the target duty ratio MDT (n) is set when the duty ratio DT (n) is calculated by the process of the previous step S200, as in the first embodiment described above. It is determined whether or not. By this determination, it is determined whether or not the current temperature of the electromagnetic coil 32 is high.

  Along with this, the time constant τ, impedance, and duty ratio corresponding to the current temperature of the electromagnetic coil 32 are calculated. And since the energization current which flows into electromagnetic coil 32 is adjusted using such a duty ratio, the energization current which flows into electromagnetic coil 32 irrespective of the temperature fluctuation of electromagnetic coil 32 in electromagnetic pressure control device 23 as an electromagnetic valve Can be accurately approximated to the control current In as the target value. Thereby, the capacity control of the compressor capacity, the suction pressure Ps, and the evaporator blowout air temperature can be adjusted well.

(Other embodiments)
In the first and second embodiments, the time constant that determines the impedance of the electromagnetic coil 32 is used as “a parameter that decreases as the temperature of the electromagnetic coil 32 increases and increases as the temperature of the electromagnetic coil 32 decreases”. However, the present invention is not limited to this, and parameters other than the time constant may be used as long as the temperature decreases as the temperature of the electromagnetic coil 32 increases and increases as the temperature of the electromagnetic coil 32 decreases. .

  In the first and second embodiments, the example of correcting the duty ratio for the electromagnetic pressure control valve that controls the discharge capacity of the variable displacement compressor is shown as the electromagnetic valve for controlling the air conditioner. Absent. That is, it may be a capacity control valve used in a flow control variable capacity compressor that controls the discharge capacity in accordance with the discharge flow rate. Furthermore, any solenoid valve may be used as long as the energization amount is duty controlled.

  In the first and second embodiments, the example in which the control current In (n) is set in step S100 described above has been described, but instead, the target duty ratio MDT (n) may be set. .

  In the first and second embodiments, the example in which the current duty ratio DT (n) is calculated using the control current In (n) in the above-described step S200 has been described. The current duty ratio DT (n) may be calculated using the ratio MDT (n).

  Further, the present invention is not limited to the above embodiment, and a parameter that changes linearly or exponentially with the temperature change of the electromagnetic coil may be set as a parameter. You may make it set a parameter based on temperature or external temperature. The duty ratio calculating means may determine the duty ratio using a weighted moving average.

  Hereinafter, the correspondence relationship between the above embodiment and the configuration of the scope of the claims will be described. The control process in step S190 corresponds to the impedance estimation means, the control process in step S200 corresponds to the duty ratio calculation means, and the valve drive circuit. 41 corresponds to applied voltage adjustment means, step S100 corresponds to current target value setting means, control processing in step S160 corresponds to previous current target value setting presence / absence determination, and control processing in step S170 corresponds to first setting means. The control process of step S180 corresponds to the second setting means, the control process of step S110 and the power supply voltage detection circuit 43 constitute a voltage detection means, and the control process of step S120 and the current measurement circuit 42 The current detection unit is configured, and the control processing in step S150 corresponds to the impedance calculation unit.

1 is an overall configuration diagram of a first embodiment of the present invention. It is a longitudinal cross-sectional view of a variable capacity compressor. (A), (b) is the schematic diagram for action | operation description at the time of the large capacity | capacitance of the compressor of FIG. (A), (b) is the schematic diagram for action | operation description at the time of the small capacity | capacitance of the compressor of FIG. FIG. 3 is a characteristic diagram showing a relationship between a control current In and a set pressure of a suction pressure Ps of an electromagnetic pressure control device installed in the compressor of FIG. 2. It is a flowchart which shows the control processing of 1st Embodiment. It is a characteristic view which shows the relationship between the control current In of the electromagnetic pressure control apparatus of the 2nd Embodiment of this invention, and the setting pressure of the suction pressure Ps.

Explanation of symbols

2 ... Compressor, 6 ... Evaporator, 9 ... Electromagnetic clutch,
13 ... Evaporator outlet temperature sensor, 16 ... Swash plate,
23 ... Electromagnetic pressure control device, 24 ... Discharge pressure chamber, 25 ... Suction pressure chamber,
26 ... Control pressure chamber, 27 ... Valve, 28 ... Variable throttle, 30 ... Bellows,
32 ... Electromagnetic coil, 40 ... CPU, 41 ... Valve drive circuit,
42 ... Current measurement circuit, 43 ... Power supply voltage detection circuit.

Claims (3)

Impedance estimation means (S190) for estimating the impedance of the electromagnetic coil (32) of the electromagnetic valve (23);
A duty ratio calculating means (S200) for calculating a duty ratio (DT (n)) for controlling a current flowing through the electromagnetic coil (32) based on the impedance estimated by the impedance estimating means (S190);
An electromagnetic valve control device comprising: an applied voltage adjusting means (41) for applying a voltage to the electromagnetic coil such that a ratio of a voltage application time per unit time becomes a duty ratio calculated by the duty ratio calculating means. Because
The impedance estimation means (S190) repeatedly estimates the impedance using a parameter set so as to change with a temperature change of the electromagnetic coil (32) ,
The duty ratio calculating means (S200) calculates the duty ratio based on the estimated impedance every time the impedance estimating means (S190) estimates the impedance.
Each time the duty ratio calculating means (S200) calculates the duty ratio, the applied voltage adjusting means (41) applies a voltage application time per unit time to the electromagnetic coil (32) based on the calculated duty ratio. To adjust the percentage of
Current target value setting means (S100) for setting a target value (In (n)) of the current flowing through the solenoid valve (32);
The duty ratio calculation means (S200) calculates the duty ratio (DT (n)) so that the current flowing through the electromagnetic coil (32) approaches the target value.
The previous current for determining whether or not the target value (In (n)) has been set by the current target value setting means (S100) when the duty ratio calculation means (S200) previously calculated the duty ratio. Target value setting presence / absence determination (S160),
When the previous current target value setting presence / absence determination (S160) determines that the target value has been set by the current target value setting means (S100) when the duty ratio calculation means has previously calculated the duty ratio. Is a first setting means (S170) for setting the parameter so that the impedance is increased by assuming that the temperature of the electromagnetic coil (32) is high at present.
When the previous current target value setting presence / absence determination (S160) determines that the target value has not been set by the current target value setting means (S100) when the duty ratio calculation means previously calculated the duty ratio Compared with the case where the previous current target value setting presence / absence determination (S160) determines that the target value has been set by the current target value setting means (S100), the temperature of the electromagnetic coil is currently lower. Second setting means (S180) for setting the parameter so that the impedance is reduced as it is in a state,
The impedance estimation means (S190) estimates the impedance using a parameter set in one of the first and second setting means, and controls the electromagnetic valve. The duty ratio calculating means (S200) calculates the duty ratio (DT (n)) so as to approach a target duty ratio (MDT (n)) indicating a target value of the current,
In the previous current target value setting presence / absence determination (S160), when the duty ratio calculation means (S200) has previously calculated the duty ratio, the current target value setting means (S100) sets the target value (In (n)). ) by to determine whether or not been set, the target duty ratio (MDT (n)) control of the solenoid valve according to claim 1, characterized in that to determine whether or not the set . Voltage detection means (S110, 43) for repeatedly detecting a voltage value applied to the electromagnetic coil (32);
Current detecting means (S120, 42) for repeatedly detecting a current value flowing through the electromagnetic coil (32);
The duty ratio (DT (n)) previously calculated by the duty ratio calculation means, the voltage value detected this time by the voltage detection means (S110, 43), and the current detection means (S120, 42) Impedance calculation means (S150) for calculating an actual impedance when the duty ratio was calculated by the duty ratio calculation means (S200) last time based on the current value,
Said impedance estimating means (S190), by correcting the actual impedance of the previous calculated by the impedance calculating means (150) by said parameter claim 1 or, characterized in that estimating the current impedance The control apparatus of the solenoid valve of 2 .

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