JP2009061937A - Vehicular refrigeration cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular refrigeration cycle device suppressing frost of an evaporator by improving temporal displacement distribution of temperature of the evaporator. <P>SOLUTION: The vehicular refrigeration cycle device comprises a compressor 1 for inhaling and discharging a coolant in a refrigeration cycle, an evaporator 6 connected to an intake side of the compressor 1 for evaporating a low-pressure coolant by absorbing heat from air blown to a space to be air-conditioned, an accumulator 7 separating a gas-liquid double phase coolant from the evaporator 6 into a gas phase coolant and a liquid phase coolant and making the compressor 1 absorb the gas phase coolant, and a control device 100 for supplying control electric current which controls a coolant flow rate discharged from the compressor 1. The compressor 1 is operated by ON-OFF control in idling, and the control device 100 supplies the control electric current so as to gradually set the current up at the time of turning ON in the ON-OFF control. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle apparatus for a vehicle that controls a refrigerant discharge flow rate of a compressor by ON-OFF control.

  In the conventional vehicular refrigeration cycle apparatus, the discharge refrigerant flow rate of the compressor is appropriately controlled so that the evaporator does not frost in order for the vehicular air conditioner to exhibit predetermined performance.

  For example, in the refrigeration cycle device for a vehicle described in Patent Document 1, the variable capacity compressor is controlled depending on whether or not the heat load of air flowing into the evaporator is within a heat load region in which frost generated in advance is generated. The discharge refrigerant flow rate is controlled.

  However, in the control of the compressor described in Patent Document 1, a sufficient frost prevention effect cannot be obtained when the method of controlling the flow rate of discharged refrigerant by operating the compressor ON-OFF is employed.

  Therefore, the surface temperature of the evaporator (hereinafter referred to as the evaporator temperature) that changes with this control when the discharge refrigerant flow rate is controlled by the ON / OFF control of the compressor will be described with reference to FIG. As shown in FIG. 9, the discharge refrigerant flow rate is increased or decreased by repeatedly turning on and off the compressor control current so as to become the duty value D <b> 1 (rectangular waveform in the lower part of FIG. 9). reference).

  First, the compressor is turned off (stopped). In this state, when the evaporator temperature rises and exceeds a predetermined upper limit value, a signal for operating the compressor is sent from the control device to turn it on. Operates.

  Even after the compressor is turned on, if the evaporator temperature continues to rise and reaches the highest point, it starts to decrease as the refrigerant flow rate increases, and when it falls below the predetermined upper limit value, the compressor stops. In this way, the compressor shifts from the operating state for a predetermined time to the stopped state.

Even after the compressor is stopped, the evaporator temperature continues to decrease due to a delay in the response of the cooling capacity, and starts rising again when it reaches the lowest point. When the evaporator temperature exceeds a predetermined upper limit value, the compressor enters an operating state, and the evaporator temperature reaches the highest point in the operating state for a predetermined time. It begins to fall and rise again. The evaporator temperature changes by repeating the above increase and decrease as the compressor is turned on and off.
JP 2005-178560 A

  However, in the control of the compressor described with reference to FIG. 9 above, since the evaporator temperature is lowered to the lowest point and the amount of undershoot becomes too large, there is a risk of frost generation. A temperature difference becomes large (for example, 10 degreeC or more), and there exists a possibility that the performance of an evaporator may not fully be exhibited.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicular refrigeration cycle apparatus that improves the temporal change distribution of the evaporator temperature and suppresses the frost of the evaporator. .

The present invention employs the following technical means to achieve the above object. That is, the first aspect of the refrigeration cycle apparatus for a vehicle is connected to the compressor (1, 10) for sucking and discharging the refrigerant in the refrigeration cycle, and the suction side of the compressor (1, 10), and is air-conditioned. An evaporator (6) that absorbs heat from the air blown into the target space and evaporates the low-pressure refrigerant, and a gas-phase and liquid-phase refrigerant out of the gas-liquid two-phase refrigerant from the evaporator (6) are separated, and the gas phase An accumulator (7) for sucking refrigerant into the compressor (1, 10), and a controller (100, 110) for supplying a control current for controlling the flow rate of refrigerant discharged from the compressor (1, 10). ,
The compressors (1, 10) are operated by the ON-OFF control when the vehicle is temporarily stopped, and the control devices (100, 110) supply the control current so as to gradually rise when turned ON in the ON-OFF control. It is characterized by that.

  According to this invention, when the vehicle is temporarily stopped (for example, when idling or when idling is stopped), when the compressor is ON-OFF controlled, the control current at the time of ON is supplied so as to gradually rise. Since the flow rate of refrigerant discharged from the machine is gradually increased to suppress a sudden increase in the flow rate of refrigerant flowing into the evaporator, it is possible to mitigate excessive evaporator temperature drop during ON-OFF control when the vehicle is temporarily stopped. , The time-dependent distribution of the temperature can be improved. Therefore, it is possible to provide a vehicle refrigeration cycle apparatus that achieves low fuel consumption and suppresses the frost of the evaporator.

  In addition, the control devices (100, 110) gradually increase the control current to be supplied by starting up (a constant slope), the flow rate of the refrigerant flowing in the refrigeration cycle, and the temperature of the air blown to the evaporator (6). The specific enthalpy obtained from the air volume of the air blown to the evaporator (6) and the temperature and humidity of the air blown to the evaporator (6) can be determined.

  According to each of these inventions, by detecting the heat load on the evaporator and using it for determining the start-up level of the control current that supplies this heat load, the control for suppressing the frost more accurately is performed. Can be provided.

  Further, the control device (100, 110) obtains a constant slope by using at least two pieces of information among a plurality of pieces of information used for determining the increase rate (a constant slope) of the control current. It is preferable to compare the obtained at least two constant slopes and determine the slope of the slowest slope as the final slope of the control current. According to the present invention, it is possible to provide control that can prevent frost more reliably.

  Further, the control device (100, 110) can determine the slope of the control current when the current control current is ON, using the lowest temperature of the evaporator when it has been lowered by the operation related to the previous control current ON. preferable. According to the present invention, it is possible to provide quicker and less wasteful control by applying feedback control using the actual temperature of the evaporator.

  The reference numerals in parentheses of the above means are an example showing the correspondence with the specific means described in the embodiments described later.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cycle diagram showing a schematic configuration of a vehicle refrigeration cycle apparatus according to the present embodiment. The vehicle refrigeration cycle apparatus shown as an example in the present embodiment is used in a vehicle air conditioner installed on the back side (vehicle front side) of the instrument panel in the front part of the vehicle interior, and blows air into the vehicle interior in the evaporator in the cycle. It absorbs heat from the air and contributes to cooling the passenger compartment.

  As shown in FIG. 1, the refrigeration cycle apparatus for a vehicle is a refrigeration cycle apparatus that cools the vehicle interior by an evaporator 6 that is an indoor heat exchanger. In addition to the evaporator 6, the refrigerant in the cycle is sucked. The compressor 1 which compresses in this way, the condenser 4 which is an outdoor heat exchanger, the expansion valve 5 which is pressure reduction means, and the accumulator 7 are comprised, and these become the structure connected cyclically | annularly by refrigerant | coolant piping. For heating and dehumidification of the passenger compartment, a hot water heater core that uses the cooling water of the traveling engine 8 as a heat source is provided in the air passage to heat the air that has passed through the evaporator 6.

  Furthermore, a flow rate sensor 3 that detects the flow rate of the refrigerant discharged from the compressor 1 is provided in the refrigerant pipe on the discharge side of the compressor 1. The expansion valve 5 is a temperature type, and its valve opening degree is adjusted according to the refrigerant temperature on the refrigerant outflow side of the radiator 4. Specifically, when the refrigerant pressure is higher than the pressure determined by the temperature of the radiator outlet, the valve opening degree is changed to the larger side, and the refrigerant pressure in the radiator 4 is maintained on the lower side. When the refrigerant pressure becomes lower than the pressure determined by the temperature, the valve opening degree is changed to a smaller side, and the refrigerant pressure in the radiator 4 is maintained on the higher side.

  The expansion valve 5 can be replaced with another configuration that includes means for adjusting the valve opening so as to maintain the operating efficiency of the refrigeration cycle at a predetermined high level. In this embodiment, a mechanical expansion valve that fluidly detects the temperature and pressure of the high-pressure refrigerant as a gas pressure is employed, but instead of this, an electromagnetic actuator such as a motor that adjusts the valve opening; An electric expansion valve composed of a sensor that detects the state of the high-pressure refrigerant and outputs an electric signal and a control device that controls the electromagnetic actuator in accordance with the signal can be employed.

  The accumulator 7 separates the gas-phase refrigerant and the liquid-phase refrigerant out of the gas-liquid two-phase refrigerant from the evaporator 6 during the cooling operation and sucks the gas-phase refrigerant into the compressor 1.

  The compressor 1 described as an example in the present embodiment is a variable capacity type capable of changing the compression capacity of the refrigerant, and here, a swash plate type variable capacity compressor is used. In the swash plate type variable capacity compressor, the driving force from the traveling engine 8 is transmitted to the shaft via a pulley, and the swash plate is connected to a drive plate fixed to the shaft via a guide pin fitted in a gap. It is rotated.

  A capacity control valve 2 that is a capacity control mechanism capable of controlling the discharge capacity is attached to the compressor 1. The capacity control valve 2 is actuated by a capacity control signal from the control device 100. When the displacement control valve 2 operates, the control pressure in the case of the compressor 1 changes. When the control pressure changes, the inclination angle of the swash plate changes, the stroke of the piston connected to the swash plate via the shoe changes, and the capacity of the compressor 1 changes.

  The capacity control valve 2 is an electromagnetically driven valve, and is an on-off valve whose opening degree is controlled by a control current (duty) supplied from the control device 100. The capacity control valve 2 is turned ON / OFF during idling when the vehicle is temporarily stopped, and this ON / OFF action is appropriately controlled by a control current supplied from the control device 100.

  The duty signal is a pulsed current signal that repeats ON and OFF every short time. ON / OFF of the signal corresponds to opening and closing of the capacity control valve 2. The capacity of the swash plate type variable capacity compressor decreases when the capacity control valve 2 is opened, and increases when the capacity control valve 2 is closed. Thus, by changing the duty ratio of the pulse signal, the tilt angle of the swash plate, the stroke of the piston, and the capacity of the compressor can be freely changed and controlled freely.

  The control device 100 includes a microcomputer, and receives air conditioner environment information, air conditioner operating condition information, and vehicle environment information. The air conditioner environment information includes vehicle interior temperature, solar radiation, outside air temperature, and the like. The air conditioner operating condition information includes air conditioner ON / OFF information, air conditioner mode information, set temperature, and the like. The vehicle environment information includes engine speed, accelerator opening, and the like.

  The control device 100 receives the air conditioner environment information, the air conditioner operating condition information, and the vehicle environment information, calculates them, and calculates the capacity to be set for the compressor 1. The control device 100 is also an air conditioner control amplifier, and outputs a capacity control current to the capacity control valve 2 to control the capacity of the compressor 1.

  When a driver operates an air conditioning operation panel (not shown) and an operation signal such as operation / stop of the air conditioner and a set temperature is input to the control device 100, the compressor 1 and the vehicle air conditioner are accordingly input. The operation of each device is controlled by the control device 100.

  Next, the operation based on the above configuration will be described. First, when the air conditioner is in an operating state when the vehicle is running, the compressor 1 is operated by receiving the driving force of the engine 8. At this time, the valve opening of the capacity control valve 2 is controlled by the control device 100 and adjusted to a refrigerant discharge flow rate that matches the required cooling capacity.

  When operating the compressor 1 in this manner, the control device 100 sends a control current based on the temperature of the evaporator detected by the evaporator fin temperature sensor or the like, and executes variable capacity control. In the variable capacity control at this time, an upper limit value and a lower limit value that are allowable as the evaporator temperature during cooling are set in advance, and the capacity control is performed so as to decrease the refrigerant discharge flow rate when the evaporator temperature falls below the lower limit value. The valve 2 is controlled, and when the evaporator temperature exceeds the upper limit value, the capacity control valve 2 is controlled to increase the refrigerant discharge flow rate. That is, the control device 100 has a multi-stage discharge capacity of the compressor 1 that is sufficiently higher than the two stages so that the required cooling capacity is exhibited while the vehicle is in a traveling state where the vehicle is not stopped. Alternatively, feedback control is performed so as to be continuous.

  Next, when the vehicle is stopped (idling state) due to a signal waiting or the like since the vehicle travels, ON / OFF control of the compressor 1 as shown in FIG. 2 is executed. FIG. 2 is a time chart showing the relationship between the ON / OFF control of the compressor 1 during idling and the evaporator temperature (fin temperature) that changes accordingly. This ON-OFF control is characterized by a waveform representing a change in duty while controlling the compressor 1 so as to obtain a refrigerant discharge flow rate corresponding to the required cooling capacity and repeating ON and OFF of the control current. . The waveform is not a normal rectangular wave, but is formed so that a protruding waveform having a right triangle shape is repeated.

  When a request for operating the air conditioner is input to the control device 100, the control device 100 supplies a control current at the time of ON that gradually starts up to the capacity control valve 2. The control current that gradually rises does not supply a control current having a duty D1 (for example, 20 to 100% of the maximum output value) as a target capacity at the same time as turning on, but instead of supplying a predetermined time from 0 to D1. As required, it has a slope (increase rate of control current with respect to time, here, slope D1 / (t5-t4), which corresponds to the slope of the hypotenuse of the right triangle in FIG. 2).

  By gradually starting and supplying the control current in this way, the flow rate of refrigerant discharged from the compressor 1 increases in proportion to the increase in the control current, and the evaporator 6 due to a rapid increase in the low-pressure refrigerant inflow amount. Overcooling (undershoot, temporal change distribution of the evaporator temperature being temporarily below the frost tolerance level) can be suppressed.

  Specifically, when the evaporator temperature rises and exceeds a predetermined upper limit value (a temperature lower than T2 in FIG. 2) while the compressor 1 is stopped, a signal for operating the compressor 1 is sent from the control device 100. The above-described control current is supplied to the capacity control valve 2, and the compressor 1 operates. At this time, since the control current is gradually raised and supplied, the low-pressure refrigerant flows into the evaporator 6 so as to gradually increase. After the control current is supplied, the evaporator temperature continues to rise due to a response delay and can reach the maximum temperature T2, but gradually decreases from the maximum temperature T2 without being rapidly cooled as the refrigerant flow rate gradually increases.

  When the evaporator temperature falls below the predetermined upper limit value, the control device 100 suddenly stops the supply of control current (turns OFF the ON-OFF operation), the compressor 1 also stops, and the discharge flow rate becomes zero. The control current is controlled so as to show a sharp change when decreasing rather than increasing. Thus, the compressor 1 shifts from the operating state for a predetermined time to the stopped state. Then, after the evaporator temperature falls to the minimum temperature T1, it starts to rise again and exceeds a predetermined upper limit value. Then, the control device 100 supplies the same control current to the capacity control valve 2 as before, and the compressor 1 Will be in operation. Again, the evaporator temperature reaches the maximum temperature T2 as described above, and after the supply of control current is stopped and the compressor 1 is stopped, the evaporator temperature decreases to the minimum temperature T1 and begins to increase. The evaporator temperature that increases or decreases between the maximum temperature T2 and the minimum temperature T1 by this control is, for example, within 5 ° C., and frost due to the evaporator 6 being too cold can be suppressed.

  Further, as the slope of the rise of the control current, the slope stored in advance in the control device 100 based on an empirical rule by experiment or the like may be employed as it is, or the calculation using the detected refrigerant flow rate is performed. The inclination may be obtained. When the inclination is obtained using the refrigerant flow rate, a control map that prescribes a desirable (ideal) increase rate of the refrigerant flow rate Gr (flow rate change rate of G2-G1 with respect to time ta) as shown in FIG. The information is stored in the control device 100.

  Then, the control device 100 obtains an increase (change rate) in the discharge refrigerant flow rate by the flow rate sensor 3 when determining the rising slope of the control current in the ON-OFF control of the compressor 1, and the obtained increase rate is obtained. It is determined whether or not the inclination is larger than a predetermined control map stored in advance as shown in FIG. When it is determined that the inclination is large, the control device 100 determines an inclination smaller than the inclination of the predetermined increase rate so as to reduce the increase rate of the refrigerant flow rate, and supplies a control current that satisfies the inclination to the capacity control valve 2. Supply.

  On the other hand, when it is determined that the inclination is small, the control device 100 determines an inclination larger than the inclination of the predetermined increase rate so as to increase the increase rate of the refrigerant flow rate, and the control current that satisfies the inclination is determined by the capacity control valve. 2 is supplied. That is, by applying feedback using the detected refrigerant flow rate, the control current is determined so that the actual refrigerant flow rate in the cycle approaches the ideal increase rate of the refrigerant flow rate Gr.

  As described above, the vehicle refrigeration cycle apparatus of the present embodiment absorbs heat from the compressor 1 that sucks and discharges the refrigerant in the refrigeration cycle and the air that is connected to the suction side of the compressor 1 and blows into the air-conditioning target space. An evaporator 6 for evaporating the low-pressure refrigerant, an accumulator 7 for separating the gas-phase refrigerant and the liquid-phase refrigerant from the gas-liquid two-phase refrigerant from the evaporator 6 and sucking the gas-phase refrigerant into the compressor 1; And a control device 100 that supplies a control current for controlling the flow rate of the refrigerant discharged from the compressor 1. The compressor 1 is operated by ON-OFF control during idling, and the control device 100 supplies a control current so as to gradually rise when ON in the ON-OFF control.

  According to this control, a sudden increase in the flow rate of refrigerant flowing into the evaporator 6 is suppressed by gradually increasing the flow rate of refrigerant discharged from the compressor 1, and the evaporator temperature in the ON-OFF control during idling is suppressed. An excessive decrease can be alleviated, and the temporal distribution of the temperature can be improved.

  In addition, the control device 100 determines the rising slope (increase rate) of the control current using the flow rate of the refrigerant flowing in the refrigeration cycle, thereby determining the heat load on the evaporator 6 with high accuracy and determining the rising level of the control current. It is possible to suppress frost more accurately by using it.

  Further, the control device 100 can execute the ON-OFF control only when the vehicle is stopped or idling when the vehicle is stopped. In this control, the capacity control of the compressor is executed when the vehicle is running, and the ON-OFF control is executed only when the vehicle is stopped.

(Second Embodiment)
In the second embodiment, compared to the first embodiment, the method of determining the rising slope of the control current using the above-described refrigerant flow rate is the same as the intake air temperature before passing through the evaporator 6 (the heat of the evaporator 6). A modification example in which the method is determined by using the load information (temperature of air blown to the evaporator 6), which is load information, will be described with reference to FIG. FIG. 4 is a map for determining a control current to be supplied when the compressor is ON in the control of the compressor 1 during idling.

  The control device 100 stores a control map that prescribes a predetermined control current slope (increase rate) as shown in FIG. The control device 100 uses the intake air temperature before passing through the evaporator, which is detected by the temperature sensor before the evaporator, when determining the slope of the rising of the control current in the ON-OFF control of the compressor 1. 4 is used to determine the slope of the control current.

  Specifically, when the intake air temperature before passing through the evaporator is 35 ° C. or higher, the control device 100 determines the slope of the control current corresponding to 35 ° C. in FIG. 4 (current change rate of i 2 with respect to time ta, FIG. The control current is supplied to the capacity control valve 2 so that the current increases with this inclination with respect to time. On the other hand, when the intake air temperature before passing through the evaporator is 10 ° C. or less, the control device 100 determines the slope of the control current corresponding to 10 ° C. in FIG. 4 (current change rate of i1 with respect to time tb, 2 in FIG. The control current is supplied to the capacity control valve 2 so that the current increases with this inclination with respect to time.

  Further, when the intake air temperature before passing through the evaporator is higher than 10 ° C. and lower than 35 ° C., the control device 100 has an inclination equivalent to 10 ° C. (two-dot chain line in FIG. 4) and an inclination equivalent to 35 ° C. (FIG. 4). The slope is calculated by an interpolation method from the solid line), and a control current is supplied to the capacity control valve 2 so that the current increases with the slope with respect to time.

  As described above, according to the control of the present embodiment, the heat load on the evaporator 6 is accurately detected from the intake air temperature before passing through the evaporator 6, and the startup level of the control current for supplying this heat load is determined. By making use of it, it is possible to execute control for suppressing frost more accurately.

(Third embodiment)
In the third embodiment, compared to the second embodiment, the method of determining the slope of the rise of the control current using the above-described suction air temperature before passing through the evaporator is the air flow level of the blower to the evaporator 6 by the blower. A modification example in which the method is determined by using the method of determining by using (the amount of air flow blown to the evaporator 6 which is the heat load information of the evaporator 6) will be described with reference to FIG. FIG. 5 is a map for determining a control current to be supplied when the compressor is ON in the control of the compressor 1 during idling.

  The control device 100 stores in advance a control map that defines a predetermined control current slope (increase rate) as shown in FIG. And the control apparatus 100 determines the inclination of control current from the control map of FIG. 5 using the setting air volume level of an air conditioner, when determining the inclination of the rise of control current in the ON-OFF control of the compressor 1. .

  Specifically, when the set airflow level is Hi (large airflow), the control device 100 determines the slope of the control current corresponding to Hi in FIG. 5 (current change rate of i4 with respect to time ta, solid line in FIG. 5). The control current is supplied to the capacity control valve 2 such that the current increases with this inclination with respect to time. On the other hand, when the set air volume level is Lo (small air volume), the control device 100 determines the slope of the control current corresponding to Lo in FIG. 5 (current change rate of i3 with respect to time tb, two-dot chain line in FIG. 5). The control current is supplied to the capacity control valve 2 such that the current increases with this inclination with respect to time.

  Further, when the set air volume level is an air volume between Hi and Lo, the control device 100 is intermediate between the slope corresponding to Lo (two-dot chain line in FIG. 5) and the slope equivalent to Hi (solid line in FIG. 4). A slope is calculated, and a control current is supplied to the capacity control valve 2 such that the current increases with the slope with respect to time.

  As described above, according to the control of the present embodiment, the thermal load on the evaporator 6 is accurately detected from the air flow level of the blower to the evaporator 6 and the startup level of the control current for supplying this thermal load is determined. By making use of it, it is possible to execute control for suppressing frost more accurately.

(Fourth embodiment)
Compared to the second embodiment, the fourth embodiment uses a heat load information of the evaporator 6 to determine the slope of the rise of the control current using the above-described blower blower air flow level to the evaporator 6. A modified example in which the constant inclination is determined by using the specific enthalpy (KJ / Kg) of air blown to an evaporator 6 will be described with reference to FIG. FIG. 6 is a map for determining a control current to be supplied when the compressor is ON in the control of the compressor 1 during idling.

  The control device 100 stores in advance a control map that defines a predetermined control current slope (increase rate) as shown in FIG. The control device 100 detects the temperature and humidity of the air blown to the evaporator by the temperature sensor and the humidity sensor when determining the slope of the rise of the control current in the ON / OFF control of the compressor 1, The slope of the control current is determined from the control map of FIG. 6 using the specific enthalpy calculated from the detected temperature and humidity.

  Specifically, when the calculated specific enthalpy is equal to or greater than h1, the control device 100 employs the slope of the control current corresponding to h1 in FIG. 6 (current change rate of i6 with respect to time ta, solid line in FIG. 6). Then, a control current is supplied to the capacity control valve 2 so that the current increases with this inclination with respect to time. On the other hand, when the calculated specific enthalpy is equal to or less than h2, the control device 100 employs the slope of the control current corresponding to h2 in FIG. 6 (current change rate of i5 with respect to time tb, two-dot chain line in FIG. 6). Then, a control current is supplied to the capacity control valve 2 so that the current increases with this inclination with respect to time.

  In addition, when the calculated specific enthalpy is a value between h1 and h2, the control device 100 performs an interpolation method from an inclination equivalent to h2 (two-dot chain line in FIG. 6) and an inclination equivalent to h1 (solid line in FIG. 5). Then, a control current is supplied to the capacity control valve 2 so that the current increases with the inclination with respect to time.

  As described above, according to the control of the present embodiment, the control load for accurately detecting the heat load on the evaporator 6 from the specific enthalpy (KJ / Kg) of the air blown to the evaporator 6 and supplying this heat load. By utilizing this for determining the start-up level, control can be performed to more accurately suppress frost.

(Fifth embodiment)
In the fifth embodiment, with respect to the method for determining the rising slope of the control current described in the first to fourth embodiments, the minimum temperature of the evaporator when the control current is turned on last time is used. An application of a method for determining the slope of the control current when the control current is turned on (so-called feedback control) will be described with reference to FIG. FIG. 7 is a time chart showing the relationship between the ON-OFF control and the evaporator temperature that changes in accordance with the ON-OFF control in the control of the compressor 1 during idling.

  When a signal for operating the compressor 1 is sent from the control device 100 while the compressor 1 is stopped at idling, the control current is supplied to the capacity control valve 2 and the compressor 1 is operated. The first control current has a rising slope of D1 / (t1-t0), and the evaporator temperature is decreased from T3 to T0 by this control current. Here, since the evaporator temperature is set to be equal to or higher than the temperature T1 in the control device 100 to prevent frost, T1-T0 is an undershoot amount of the evaporator temperature.

  Therefore, when the control current is supplied for the second time, the control device 100 uses the minimum temperature T0 of the evaporator 6 when the control current has been lowered by the control current turned on for the first time (previous time), and uses the undershoot amount (T1-T0). ) Is calculated. Furthermore, the control device 100 determines the rising slope of the second control current based on the calculated undershoot amount. This slope is determined to be a value that is inversely proportional to the calculated undershoot amount. Here, since the second control current is a temperature that is below the lower limit of frost prevention at the first time, it is determined to have a gentler slope D1 / (t3-t2) than the first slope.

  As described above, according to the control of the present embodiment, the initial increase rate of the next control current is determined using the actual temperature of the evaporator 6, so that the frost can be prevented more quickly and wasteful without excess or deficiency. Less control can be implemented.

(Sixth embodiment)
6th Embodiment demonstrates the embodiment at the time of using an electric compressor as a compressor with respect to the refrigerating-cycle apparatus for vehicles of 1st Embodiment using FIG. In FIG. 8, the same reference numerals as those in FIG. 1 are the same components, and have the same effects and operations. FIG. 8 is a cycle diagram showing a schematic configuration of the vehicle refrigeration cycle apparatus of the present embodiment. In addition, the compressor 10 of this embodiment is applicable also to 2nd Embodiment-5th Embodiment.

  As shown in FIG. 8, the compressor 10 is an electric compressor for a fixed capacity hybrid vehicle, and is configured integrally with a motor 11. The target vehicle in the present embodiment is an idling stop vehicle in which the engine 8 stops when the vehicle is temporarily stopped due to a signal or the like. In this vehicle, when the vehicle refrigeration cycle is operating, the compressor 10 is operated via a pulley or a belt using the engine 8 as a drive source while the vehicle is running, and when the engine 8 stops when the vehicle stops, a battery (not shown) ), The compressor 10 is operated using the motor 11 that is operated by the power source from the power source.

  The motor 11 has a structure in which the rotation speed is controlled by the control device 110 controlling the control current for the ON-OFF operation, and the discharge refrigerant capacity of the compressor 10 changes according to the rotation speed of the motor 11. It is like that. The rotation speed of the motor 11 is controlled by a control current (duty) supplied from the control device 110.

  When the vehicle is temporarily stopped, it is determined that the engine 8 is in a stopped state based on the engine speed signal and the idle stop determination signal, and if there is a request signal for air conditioner operation in the control device 110, the control device 110 is in the stopped state. A control current is supplied to a certain motor 11 to operate the compressor 10. And the ON-OFF control at this time is appropriately controlled by the control current supplied from the control device 110 as in the first embodiment, and has the same effects as the first embodiment.

  Thus, this embodiment is connected to the suction side of the electric compressor (compressor 10) that sucks and discharges the refrigerant in the refrigeration cycle, and absorbs heat from the air blown into the air-conditioning target space to absorb the low-pressure refrigerant. An evaporator 6 that evaporates the vapor, an accumulator 7 that separates the gas-phase refrigerant and the liquid-phase refrigerant out of the gas-liquid two-phase refrigerant from the evaporator 6, and sucks the gas-phase refrigerant into the compressor 1; And a control device 100 that supplies a control current for controlling the refrigerant flow rate. The electric compressor is operated by the ON-OFF control when idling is stopped, and the control device 100 supplies the control current so as to gradually rise when it is turned ON in the ON-OFF control.

  According to this control, since the discharge refrigerant flow rate of the compressor 10 is gradually increased, a rapid increase in the refrigerant flow rate flowing into the evaporator 6 can be suppressed. Therefore, the evaporator temperature in the ON-OFF control when idling is stopped. Of the temperature can be alleviated, and the temporal distribution of the temperature can be improved.

(Other embodiments)
In the above-described embodiment, the preferred embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. It is.

  For example, four control maps are shown in the first to fourth embodiments as control maps for determining the control current to be supplied when the compressor is turned on, but at least two control maps are used among these maps. The waveform of the control current may be determined. In this case, the control current waveform is calculated for each of the two or more control maps to be used, and these are compared, and the waveform having the slowest rise (slope) of the control current is determined as the final control current. I decided to.

  That is, the control devices 100 and 110 obtain at least two pieces of information from among the plurality of pieces of information described in the first to fourth embodiments that are used to determine the increase rate (a constant slope) of the control current. Each of them is used to obtain a certain slope, and at least two constant slopes obtained are compared, and the slope having the slowest slope is determined as the final slope of control current (control current increase rate). . Thereby, control from safety is performed and reliable frost prevention can be implemented.

  Further, the waveform of the control current supplied when the compressor is turned on is not limited to the linear waveform of the rising edge, and may be a gradually rising shape, for example, a quadratic curve shape. Good.

  Moreover, although the target vehicle is an idling stop vehicle, the sixth embodiment may be applied to a hybrid vehicle in which the engine is stopped mainly when traveling at a low speed and when it is stopped. There is an effect.

It is a cycle figure showing the schematic structure of the refrigeration cycle device for vehicles of a 1st embodiment. In the refrigeration cycle apparatus for vehicles of a 1st embodiment, it is a time chart which showed the relation between the control of the compressor at the time of idling, and the evaporator temperature which changes in connection with this. In the control of the compressor during idling according to the first embodiment, it is a map for determining a control current to be supplied when the compressor is ON. In the control of the compressor during idling according to the second embodiment, it is a map for determining a control current to be supplied when the compressor is ON. In the control of the compressor during idling according to the third embodiment, it is a map for determining a control current to be supplied when the compressor is ON. In the control of the compressor during idling according to the fourth embodiment, it is a map for determining a control current to be supplied when the compressor is ON. In the control of the compressor at the time of idling concerning a 5th embodiment, it is a time chart which showed the relation between ON-OFF control and the evaporator temperature which changes in connection with this. It is a cycle figure showing the schematic structure of the refrigeration cycle device for vehicles of a 6th embodiment. In the conventional vehicle refrigeration cycle apparatus, it is the time chart which showed the relationship between the ON-OFF action | operation of a compressor, and the surface temperature of the evaporator which changes in connection with this.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 10 ... Compressor 6 ... Evaporator 2 ... Capacity control valve 7 ... Accumulator 100, 110 ... Control apparatus

Claims (7)

Compressors (1, 10) for sucking and discharging refrigerant in the refrigeration cycle;
An evaporator (6) connected to the suction side of the compressor (1, 10) and absorbing heat from the air blown into the air-conditioning target space to evaporate the low-pressure refrigerant;
An accumulator (7) for separating the gas-phase refrigerant and the liquid-phase refrigerant from the gas-liquid two-phase refrigerant from the evaporator (6), and sucking the gas-phase refrigerant into the compressor (1, 10);
A control device (100, 110) for supplying a control current for controlling the flow rate of refrigerant discharged from the compressor (1, 10),
The compressors (1, 10) are operated by ON-OFF control when the vehicle is temporarily stopped,
The refrigeration cycle apparatus for vehicles, wherein the control device (100, 110) increases and supplies a control current for gradually turning on in the ON-OFF control.   The control device (100, 110) gradually raises and supplies the control current so as to give a constant slope representing a current increase rate, and uses the refrigerant flow rate flowing in the refrigeration cycle to tilt the control current. The vehicle refrigeration cycle apparatus according to claim 1, wherein:   The control device (100, 110) gradually raises and supplies the control current so as to give a constant slope representing the rate of increase in current, and uses the temperature of the air blown to the evaporator (6). The vehicular refrigeration cycle apparatus according to claim 1, wherein an inclination of the control current is determined.   The control device (100, 110) gradually raises and supplies the control current so as to give a constant slope representing the rate of increase in current, and uses the amount of air blown to the evaporator (6). The vehicular refrigeration cycle apparatus according to claim 1, wherein an inclination of the control current is determined.   The control device (100, 110) gradually raises and supplies the control current so as to give a constant slope representing the current increase rate, and the temperature and humidity of the air blown to the evaporator (6). The vehicle refrigeration cycle apparatus according to claim 1, wherein the constant inclination is determined using a specific enthalpy obtained from the equation (1).   The control device (100, 110) uses the at least two pieces of information to determine the constant slope among the information used to determine the slope of the control current according to claims 2 to 5. A vehicle refrigeration cycle apparatus characterized in that each is obtained, and the obtained at least two constant inclinations are compared to determine the final inclination of the control current with the gentlest inclination.   The control device (100, 110) determines the slope of the control current when the current control current is ON, using the lowest temperature of the evaporator when it has been lowered by the operation related to the previous control current ON. The vehicular refrigeration cycle apparatus according to any one of claims 2 to 6, wherein

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