Warm core temperature estimation method and device, computer equipment and computer program product

Abstract

The invention discloses a warm core temperature estimation method and device, computer equipment and a computer program product, and the warm core temperature estimation method comprises the following steps: according to a warm core temperature estimation coefficient theta h, an enthalpy value h2 of CO2 at an outlet side of a compressor, an enthalpy value h3 of CO2 at an outlet side of a gas cooler, and an equivalent enthalpy value hg of CO2 in a transcritical zone representing the warm core temperature, calculating a warm core temperature estimation coefficient theta h; determining the equivalent enthalpy value hg, est of the transcritical zone CO2 representing the warm core temperature according to the reference value hmin of the est; and according to the equivalent enthalpy value hg, est and the pressure Pg, hi of the CO2 in the transcritical zone, the estimated temperature Tg, est of the warm core is determined. According to the warm core temperature estimation method, the warm core temperature is mapped through the equivalent enthalpy value of the CO2 in the transcritical zone based on the sensible-heat-like heat exchange characteristic of the CO2 heat pump system on the high-pressure side, and the accuracy of warm core temperature estimation can be improved.

Description

Technical Field

[0001] This application relates to the field of thermal management technology, and in particular to a method, apparatus, computer equipment, and computer program product for predicting the core temperature of a CO2 transcritical single-stage heat pump system with return heat. Background Technology

[0002] Most thermal management solutions for new energy vehicles adopt heat pump systems. Among them, CO2 heat pump systems have advantages such as good low-temperature heating performance, green and high energy efficiency, good safety and chemical stability, and have broad application prospects in the thermal management of new energy vehicles in the future.

[0003] When a heat pump system is operating, the core temperature of the passenger compartment needs to be used as the control target for the compressor during heating. For CO2 heat pump systems, CO2 is generally operated in the transcritical region, and a regenerator is added to the system. Low-temperature, low-pressure CO2 gas enters the compressor, is compressed, and then enters the supercritical region, where it exchanges heat with the external medium through a high-pressure side sensible heat exchange method (without latent heat exchange or condensation processes). Most properties of CO2 change with temperature, and pressure changes also cause property changes; the trends of these changes differ at different temperatures and pressures.

[0004] Since the high-pressure side of a CO2 heat pump system uses a sensible heat exchange method, the traditional method of calculating the core temperature based on the saturation temperature corresponding to the high-pressure side pressure in a direct heat pump with R134a refrigerant is not well applied. On the other hand, the method based on interpolation fitting of the temperatures before and after the cooler has disadvantages such as weak principle, large fitting error, and large calibration workload.

[0005] In view of this, for CO2 transcritical single-stage heat pump systems with recirculation, how to provide a method for predicting the core temperature that can accurately predict the core temperature is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this application is to provide a method, apparatus, computer equipment, and computer program product for predicting the core temperature of a CO2 transcritical single-stage heat pump system with a return heat cycle. The core temperature prediction method is based on the sensible heat transfer characteristics of the CO2 heat pump system on the high-pressure side, and uses the equivalent enthalpy value of CO2 in the transcritical region to map the core temperature, which can improve the accuracy of core temperature prediction.

[0007] To address the aforementioned technical problems, this application provides a method for predicting the temperature of a heating element, which includes the following steps:

[0008] Based on the temperature prediction coefficient θ of the heating element hThe enthalpy h2 of CO2 at the compressor outlet, the enthalpy h3 of CO2 at the gas cooler outlet, and the equivalent enthalpy h of transcritical CO2 characterizing the warm core temperature. g,est The baseline value h min Determine the equivalent enthalpy h of CO2 in the transcritical region, characterizing the warm core temperature. g,est ;

[0009] According to the equivalent enthalpy value h g,est and the pressure P of CO2 in the transcritical region g,hi Determine the estimated temperature T of the heating element g,est .

[0010] In one feasible solution, the enthalpy h2 of CO2 at the compressor outlet is determined based on the enthalpy h of CO2 at the compressor outlet under isentropic compression. 2,is The adiabatic efficiency η of the compressor is And the enthalpy h1 of CO2 at the compressor inlet side is determined;

[0011] The enthalpy h3 of CO2 at the outlet side of the gas cooler is determined by the inlet air mass m. g The equivalent temperature difference ΔT of the heating core g CO2 mass flow rate m r And the enthalpy h2 of CO2 at the compressor outlet side is determined.

[0012] In one feasible solution, the enthalpy h3 of CO2 at the outlet side of the gas cooler is determined according to formula c. g m g △T g =m r (h3-h2) is determined, where c g This is the specific heat capacity of air at constant pressure.

[0013] In one feasible scheme, the enthalpy h of CO2 at the compressor outlet side under isentropic compression is... 2,is Through the shaft power W of the compressor shaft The adiabatic efficiency η of the compressor is The enthalpy h1 of CO2 at the compressor inlet and the mass flow rate m of CO2. r It is determined that the shaft power W of the compressor is... shaft Through the actual power E of the compressor com and the motor efficiency η of the compressor motor Sure.

[0014] For example, the enthalpy h of CO2 at the compressor outlet side under isentropic compression 2,is Determined according to the following formula:

[0015] E com =W shaft / η motor ;

[0016] W shaft =m r (h 2,is -h1) / η is .

[0017] In one feasible approach, the mass flow rate of the CO2 is determined according to the following formula: m r =η v V com ρ s ;

[0018] Where, η v V is the volumetric efficiency of the compressor. com ρ is the theoretical intake capacity of the compressor. s This refers to the refrigerant density at the compressor's suction port.

[0019] In one feasible solution, the volumetric efficiency of the compressor is determined according to formula η. v =k1-k2·P d / P s Confirmed; the motor efficiency of the compressor is based on formula η. motor =k3+k4·P d / P s Confirmed; the adiabatic efficiency of the compressor is determined according to formula η. is =k5-k6·P d / P s Sure;

[0020] Among them, k1, k2, k3, k4, k5 and k6 are correction coefficients.

[0021] In one feasible solution, the enthalpy h2 of CO2 at the compressor outlet is determined according to the following formula: W shaft =m r (h2-h1)=m r (h 2,is -h1) / η is .

[0022] In one feasible solution, the intake air quality is determined based on the actual speed or actual voltage percentage of the blower, the internal and external circulation ratio of the vehicle air conditioning system, the ambient temperature, and the interior temperature of the vehicle.

[0023] The equivalent temperature difference of the heating element is determined based on the internal and external circulation ratio of the vehicle air conditioning system, the ambient temperature, the interior temperature, the temperature of the air outlet blowing on the face, the temperature of the air outlet blowing on the feet, and the temperature of the defrost air outlet.

[0024] In one feasible solution, the equivalent enthalpy value h g,est According to formula hg,est =h min +θ h (h2-h min )+(1-θ h (h) min -h3) confirmed.

[0025] In one feasible solution, the reference value h min The temperature T of CO2 in the transcritical region g,hi enthalpy value h g,hi Sure.

[0026] In one feasible solution, the reference value h min Determined according to the following formula:

[0027] .

[0028] This application embodiment also provides a heating core temperature prediction device, the heating core temperature prediction device comprising:

[0029] The acquisition module is used to obtain the temperature prediction coefficient θ of the heating element. h The enthalpy h2 of CO2 at the compressor outlet, the enthalpy h3 of CO2 at the gas cooler outlet, and the equivalent enthalpy h of transcritical CO2 characterizing the warm core temperature. g,est The baseline value h min And the pressure P of CO2 in the transcritical region g,hi ;

[0030] The first calculation module is used to estimate the temperature of the heating element based on the temperature prediction coefficient θ. h The enthalpy h2 of CO2 at the compressor outlet, the enthalpy h3 of CO2 at the gas cooler outlet, and the reference value h min Determine the equivalent enthalpy value h. g,est ;

[0031] The second calculation module is used to calculate based on the equivalent enthalpy value h. g,est and the pressure P of CO2 in the transcritical region g,hi Determine the estimated temperature T of the heating element g,est .

[0032] This application also provides a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to perform the aforementioned warm core temperature prediction method.

[0033] This application also provides a computer program product, including a computer program that, when triggered by a processor, can execute the warm core temperature prediction method described in any of the preceding claims.

[0034] By adopting the solution provided in this application, utilizing the characteristics of the refrigerant CO2, considering the sensible heat transfer characteristics of CO2 on the high-pressure side of the heat pump system, and using the equivalent enthalpy value of CO2 in the transcritical region to characterize the warm core temperature, the prediction accuracy of the warm core temperature in the CO2 transcritical single-stage recirculating heat pump system can be improved, thereby better controlling the operation of the compressor and enabling the heat pump system to have better functional performance. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the CO2 transcritical single-stage heat pump system with heat return cycle provided in a specific embodiment of this application.

[0036] Figure 2 The pressure-enthalpy diagram of CO2 transcritical single-stage cyclothermal cycle operation in the specific embodiments provided in this application;

[0037] Figure 3 This is a flowchart illustrating the method for predicting the temperature of the heating core provided in this application.

[0038] Explanation of reference numerals in the attached figures:

[0039] Compressor 11, gas cooler 12, regenerator 13, throttle valve 14, evaporator 15. Detailed Implementation

[0040] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the CO2 transcritical single-stage heat pump system with regenerative cycle provided in the specific embodiments of this application.

[0042] like Figure 1 As shown, the CO2 transcritical single-stage regenerative cycle heat pump system includes a compressor 11, a gas cooler 12, a regenerator 13, a throttling valve 14, and an evaporator 15. The outlet of the compressor 11 is connected to the inlet of the gas cooler 12, the outlet of the gas cooler 12 is connected to the throttling valve 14 via the regenerator 13, the outlet of the throttling valve 14 is connected to the evaporator 15, and the outlet of the evaporator 15 is connected to the inlet of the compressor 11 via the regenerator 13.

[0043] This heat pump system uses CO2 as the refrigerant and employs transcritical cycle technology, which adjusts the pressure of CO2 above its critical point, giving it characteristics of both liquid and gaseous states. This cycle method offers high thermal efficiency and environmental friendliness. The system includes a regenerator 13, enabling internal heat exchange between the high-temperature refrigerant before the expansion valve and the low-temperature refrigerant from the evaporator. This results in the high-temperature refrigerant being further subcooled by releasing heat to the low-temperature refrigerant, while the low-temperature refrigerant is superheated by absorbing heat from the high-temperature refrigerant.

[0044] During operation, the high-temperature refrigerant flowing through the gas cooler 12 releases heat to the outside air, and the generated warm air is sent into the crew cabin through the air duct by the blower.

[0045] Please refer to this as well. Figure 2 , Figure 2 The pressure-enthalpy diagram for the transcritical single-stage cyclothermal cycle of CO2 in the specific embodiments provided in this application.

[0046] Figure 2 The closed, thick black line in the middle indicates Figure 1 The heating cycle of the heat pump system shown is as follows: Points 1 to 2 correspond to the inlet and outlet of compressor 11; points 2 to 3 correspond to the inlet and outlet of gas cooler 12; points 3 to 4 correspond to the inlet and outlet of regenerator 13; points 4 to 5 correspond to the inlet and outlet of expansion valve 14; points 5 to 6 correspond to the inlet and outlet of evaporator 14; and points 6 to 1 correspond to the inlet and outlet of regenerator 13. Points 1 to 2... is This indicates the isentropic compression process of compressor 11.

[0047] Figure 2 The thin solid lines in the diagram represent isotherms.

[0048] When the heat pump system is running, the control target of the compressor is the heating core temperature. Specifically, the temperature of the high-pressure refrigerant flowing through the gas cooler 12 is used as the estimated value of the actual heating core temperature. The estimated heating core temperature will affect the functional performance of the heat pump system.

[0049] Since this heat pump system uses CO2 as the refrigerant, the traditional method for predicting the core temperature of R134a refrigerant heat pumps is not applicable. This application proposes a method for predicting the core temperature of a CO2 transcritical single-stage heat pump system with a return heat cycle.

[0050] Please refer to this as well. Figure 3 , Figure 3 This is a flowchart illustrating the method for predicting the temperature of the heating core provided in this application.

[0051] This embodiment provides a method for predicting the core temperature, used in a CO2 transcritical single-stage heat pump system with return flow, which can be combined with the aforementioned method. Figure 1 To understand the structure shown, refer to its pressure-enthalpy diagram. Figure 2 understand.

[0052] The method for predicting the temperature of the heating element includes:

[0053] Determine the temperature prediction coefficient θ of the heating element h The enthalpy h2 of CO2 at the outlet side of compressor 11, the enthalpy h3 of CO2 at the outlet side of gas cooler 12, and the equivalent enthalpy h of transcritical CO2 characterizing the warm core temperature. g,est The baseline value h min (Hereinafter referred to as the benchmark value h) min );

[0054] Based on the temperature prediction coefficient θ of the heating element h The enthalpy h2 of CO2 at the outlet side of compressor 11, the enthalpy h3 of CO2 at the outlet side of gas cooler 12, and the reference value h min Determine the equivalent enthalpy h of transcritical CO2 to characterize the warm core temperature. g,est (Hereinafter referred to as equivalent enthalpy h) g,est );

[0055] Based on the aforementioned equivalent enthalpy value h g,est and the pressure P of CO2 in the transcritical region g,hi Determine the estimated temperature T of the heating element g,est .

[0056] Combination Figure 2 In the supercritical region, the temperature and pressure of CO2 are two independent parameters. The equivalent enthalpy h of CO2 in the transcritical region, which characterizes the warm core temperature, has been determined. g,est Then, the pressure P of CO2 in the transcritical region is considered. g,hi This allows you to determine the estimated temperature of the heating element.

[0057] The above prediction method utilizes the characteristics of the refrigerant CO2, considers the sensible heat transfer characteristics of CO2 on the high-pressure side of the heat pump system, and uses the equivalent enthalpy of CO2 in the transcritical region to characterize the warm core temperature. This can improve the prediction accuracy of the warm core temperature in the CO2 transcritical single-stage recirculating heat pump system, thereby better controlling the operation of the compressor 11 and enabling the heat pump system to have better functional performance.

[0058] In one implementation, the equivalent enthalpy value h g,est It can be determined according to the following formula:

[0059] h g,est =h min +θ h (h2-h min )+(1-θ h (h)min -h3).

[0060] The following sections will explain the temperature prediction coefficient θ of the heating element in this formula. h , reference value h min The method for determining the enthalpy h2 of CO2 at the outlet side of compressor 11 and the enthalpy h3 of CO2 at the outlet side of gas cooler 12.

[0061] In a feasible solution, the temperature prediction coefficient θ of the heating core h Temperature prediction coefficient θ of the heating element h The range of values ​​for is 0 ≤ θ h ≤1. Temperature prediction coefficient θ of the heating element. h The specific value can be determined through experiments or simulations.

[0062] For example, the parameters can be identified using the least squares method based on the vehicle's bench test data and road test data. Of course, after obtaining the relevant test data of the vehicle, other mathematical processing methods can also be used to obtain the parameters.

[0063] In an feasible solution, the baseline value h min The temperature T of CO2 in the transcritical region can be used to determine its properties. g,hi enthalpy value h g,hi Sure.

[0064] In specific implementation, such as Figure 2 As shown, above and near the quasi-critical point of CO2 (30.98℃ / 73.8bar), the isotherm changes very gradually. To the left and right of the critical point, the isotherms and isenthalpic lines (not shown in the figure, the isenthalpic lines are located at...) Figure 2 The isotherms extend almost parallel to each other along the vertical direction, and are also relatively dense in the regions on the left and right sides far from the critical point; this indicates that in the regions on the left and right sides far from the critical point, the change in enthalpy difference caused by a change in CO2 temperature per unit is much smaller than the change in enthalpy difference in the region near and above the CO2 critical point.

[0065] Therefore, in practical applications, the operating point where the slope of the isotherm under different high pressures is closest to 0 can be taken as the equivalent enthalpy value h. g,est The baseline value h min That is, the reference value h min Satisfy the following formula:

[0066] , among which, T g,hi h g,hi The values ​​represent the temperature (°C) and enthalpy (J / g) of CO2 in the transcritical region.

[0067] In one feasible scheme, the enthalpy h2 of CO2 at the outlet side of compressor 11 and the enthalpy h3 of CO2 at the outlet side of gas cooler 12 can be determined by the volumetric efficiency η of compressor 11. v Motor efficiency η motor Adiabatic efficiency η is The calculation is based on the high-low pressure ratio function, and determined using the energy conservation equation and the CO2 refrigerant mass flow rate calculation equation under the heating cycle. Here, the high-low pressure ratio function is the ratio of the high-pressure side pressure to the low-pressure side pressure of the heat pump system. Specifically, the high-pressure side pressure can be represented by the compressor 11 discharge pressure P. d (bar) indicates that the low-pressure side pressure can be represented by the compressor 11 suction pressure P. s (bar) indicates.

[0068] In one application example, the enthalpy h2 of CO2 at the outlet side of compressor 11 is based on the enthalpy h at the outlet side of compressor 11 under isentropic compression. 2,is The adiabatic efficiency η of compressor 11 is The enthalpy h1 of CO2 at the inlet side of compressor 11 is determined.

[0069] The enthalpy h1 of CO2 at the inlet side of compressor 11 can be determined by combining the pressure-enthalpy diagram, and is the enthalpy value at the intersection of the low-pressure isobar and the saturated vapor line. The low-pressure value can be the pressure at the inlet side of compressor 11, that is, the suction pressure P of compressor 11. s The suction pressure P of compressor 11 s It can be obtained by detecting the detection component located on the suction port side of the compressor 11.

[0070] Among them, the enthalpy h at the outlet side of compressor 11 under isentropic compression 2,is The shaft power W of the compressor can be used shaft The adiabatic efficiency η of the compressor is The enthalpy h1 of CO2 at the compressor inlet and the mass flow rate m of CO2. r It is determined that the shaft power W of the compressor is... shaft Through the actual power E of the compressor com and the motor efficiency η of the compressor motor Sure.

[0071] In practice, it can be determined according to the following formula:

[0072] E com =W shaft / η motor ;

[0073] W shaft =m r (h 2,is -h1) / η is ;

[0074] In the formula, E com The actual power of compressor 11, W shaft For the shaft power of compressor 11, η motor For the motor efficiency of compressor 11, m r η is the mass flow rate of CO2. is h1 is the adiabatic efficiency of compressor 11, and h1 is the enthalpy of CO2 at the inlet side of compressor 11.

[0075] Typically, the vehicle's overall controller acquires relevant operating parameters of the compressor 11 to determine the actual power of the compressor 11, E. com It can be considered a known value and obtained directly through the vehicle controller.

[0076] Under heating cycle, the mass flow rate m of CO2 r The following formula can be used to calculate and determine: m r =η v V com ρ s In the formula, η v V is the volumetric efficiency of the compressor. com The theoretical intake capacity of the compressor (m³) 3 / s), ρ s The refrigerant density at the compressor suction port (kg / m³) 3 ).

[0077] Among them, the theoretical intake capacity V of compressor 11 com Given the refrigerant density ρ at the suction port of compressor 11. s The values ​​can be obtained by referring to a table based on the temperature and pressure at the compressor's inlet 11.

[0078] The volumetric efficiency η of the compressor involved in the above formula v The motor efficiency η of the compressor motor And the compressor's adiabatic efficiency η is All can be based on the discharge pressure P of compressor 11 d and compressor 11 suction pressure P s Sure.

[0079] Among them, the discharge pressure P of compressor 11 d and compressor 11 suction pressure P s This can be detected by detection components respectively located on the suction port side and the discharge port side of the compressor 11. For example, the detection components may be pressure sensors.

[0080] In one implementation scheme, the volumetric efficiency η of the compressor v The motor efficiency η of the compressor motorAnd the compressor's adiabatic efficiency η is Calculate and determine according to the following formulas respectively:

[0081] η v =k1-k2·P d / P s ;

[0082] η motor =k3+k4·P d / P s ;

[0083] η is =k5-k6·P d / P s ;

[0084] In the formula, k1, k2, k3, k4, k5 and k6 are correction coefficients.

[0085] In practical applications, the above correction coefficients can be adjusted based on experimental data or simulations after an initial value has been given.

[0086] For example, the initial values ​​of the correction coefficients k1, k2, k3, k4, k5 and k6 are 1.19379, 0.13635, 0.64107, 0.07487, 0.8014 and 0.04842, respectively.

[0087] Combining the aforementioned formulas, we can obtain the enthalpy h of CO2 at the compressor outlet under isentropic compression. 2,is The specific calculation formula is as follows:

[0088] h 2,is =E com η is η motor / m r +h1=E com η is η motor / (η v V com ρ s )+h1=[(E com •(0.8014-0.04842P d / P s •(0.64107+0.07487P) d / P s ] / [(1.19379-0.13635P d / P s V com ρ s ]+h1.

[0089] The shaft power W of compressor 11 shaftFormula W can also be used shaft =m r (h2-h1) indicates that, under isentropic compression, the enthalpy h at the outlet side of compressor 11 is determined. 2,is Then, based on the shaft power W of compressor 11 shaft The aforementioned two formulas are used to determine the enthalpy h2 of CO2 at the outlet side of compressor 11. Specifically, the formula for calculating the enthalpy h2 of CO2 at the outlet side of compressor 11 is:

[0090] h2=h 2,is / η is +(1-1 / η is )h1.

[0091] After determining the enthalpy h2 of CO2 at the outlet side of compressor 11, it can be combined with the inlet air mass m g The equivalent temperature difference ΔT of the heating core g and the mass flow rate m of CO2 r Determine the enthalpy h3 of CO2 at the outlet side of the gas cooler.

[0092] In practical implementation, the energy conservation principle under a heating cycle can be used to obtain: c g m g △T g =m r (h3-h2), thus determining the formula for calculating the enthalpy h3 of CO2 at the outlet side of gas cooler 12:

[0093] h3=c g m g △T g / m r +h2;

[0094] In the formula, c g The specific heat capacity of air at constant pressure (kJ / (kg•℃)), m g For the intake air mass (kg / s), △T g The equivalent temperature difference (°C) of the heating core, m r The mass flow rate of CO2 is (kg / s).

[0095] Among them, the specific heat capacity at constant pressure c g It can be obtained by looking up a table.

[0096] Among them, the intake air quality m g This can be calculated using the blower's airflow model. Specifically, the inlet air mass m g R is the percentage of the actual speed or actual voltage of the blower. blw R1 ratio of internal to external air circulation in vehicle air conditioning system fre Ambient temperature T os (°C) and interior temperature Tincar (°C) is related and can be determined by these parameters.

[0097] In short, m g =m g (R blw ,R fre ,T os ,T incar Depending on the vehicle model, the blower's airflow model varies, specifically in terms of intake air mass (m). g The specific calculation formulas also vary, and will not be specified here.

[0098] Among them, the equivalent temperature difference ΔT of the heating core g According to the internal and external circulation ratio R of the vehicle's air conditioning system fre Ambient temperature T os The temperature is calculated from the vehicle interior temperature (°C) and the duct temperature, etc.; the duct temperature may include the vehicle interior temperature (T). incar (°C), Air outlet temperature T face (°C), Foot air outlet temperature T foot and the defrost outlet temperature T def (°C).

[0099] In short, △Tg = △Tg(R) fre ,T os ,T incar ,T face ,T foot ,T def The specific formula for calculating the equivalent temperature difference of the heating element is not specified here.

[0100] Wherein, the mass flow rate m of CO2 r The calculation method has been given above, so it will not be repeated here.

[0101] Combination Figure 2 Under isentropic compression, the enthalpy h of CO2 at the compressor outlet is determined. 2,is Then, h can be determined based on isobars and isenthalpic lines. 2,is The location points are determined by the isobars and the h2 value, and the h3 location points are determined by the isobars and the h3 value.

[0102] As above, in determining the temperature prediction coefficient θ of the heating core h The enthalpy h2 of CO2 at the compressor outlet, the enthalpy h3 of CO2 at the gas cooler outlet, and the equivalent enthalpy h of transcritical CO2 characterizing the warm core temperature. g,est The baseline value h min Then, according to the aforementioned formula h g,est =h min +θ h (h2-hmin )+(1-θ h (h) min -h3) to calculate the equivalent enthalpy h g,est At the equivalent enthalpy h g,est Once determined, the CO2 pressure P in the transcritical region can be considered. g,hi The estimated temperature T of the heating element is calculated using (bar). g,est .

[0103] Combination Figure 2 It can be seen that in calculating the estimated temperature T of the heating core... g,est At that time, P g,hi =P 2,is The transcritical CO2 pressure P g,hi Specifically, the discharge pressure P of compressor 11 can be used. d As mentioned earlier, this information can be obtained through a detection component (such as a pressure sensor) located on the exhaust port side of the compressor 11.

[0104] As can be seen from the aforementioned method for predicting the temperature of the heating core, this method is based on the existing detection components (such as pressure sensors) on the high-pressure side and low-pressure side of the heat pump system. Combined with relevant parameters that can generally be obtained by the vehicle controller (such as the actual power of the compressor 11, the air volume model of the blower, etc.), a relatively accurate prediction of the temperature of the heating core can be achieved without the need for additional temperature sensors, which helps to reduce costs.

[0105] This application embodiment also provides a core temperature prediction device for a CO2 transcritical single-stage heat pump system with heat return cycle, the core temperature prediction device comprising:

[0106] The acquisition module is used to obtain the temperature prediction coefficient θ of the heating element. h The enthalpy h2 of CO2 at the compressor outlet, the enthalpy h3 of CO2 at the gas cooler outlet, and the equivalent enthalpy h of transcritical CO2 characterizing the warm core temperature. g,est The baseline value h min And the pressure P of CO2 in the transcritical region g,hi ;

[0107] Among them, the temperature prediction coefficient θ of the heating core h The determination method is as described in the previous section on the method for predicting the temperature of the heating core. After being determined by experiments or simulations, it can be pre-stored in the acquisition module or stored in the vehicle controller for later use by the acquisition module.

[0108] Among them, the enthalpy h2 of CO2 at the compressor outlet, the enthalpy h3 of CO2 at the gas cooler outlet, and the equivalent enthalpy h of transcritical CO2 characterizing the warm core temperature are included. g,est The baseline value h minThe method for determining the core temperature is as described above in the section on the method for estimating the core temperature, and will not be repeated here.

[0109] The first calculation module is used to estimate the temperature prediction coefficient θ of the heating element. h The enthalpy of CO2 at the compressor outlet (h2), the enthalpy of CO2 at the gas cooler outlet (h3), and the reference value (h) min Determine the equivalent enthalpy h g,est .

[0110] In one implementation, the first calculation module pre-stores the formula h. g,est =h min +θ h (h2-h min )+(1-θ h (h) min -h3), based on the temperature prediction coefficient θ of the heating core determined by the acquisition module. h The enthalpy of CO2 at the compressor outlet (h2), the enthalpy of CO2 at the gas cooler outlet (h3), and the reference value (h) min The equivalent enthalpy h can be determined. g,est .

[0111] The second calculation module is used to calculate based on the equivalent enthalpy value h. g,est and the pressure P of CO2 in the transcritical region g,hi Determine the estimated temperature T of the heating element g,est .

[0112] In addition to the aforementioned method and apparatus for predicting the core temperature of a CO2 transcritical single-stage heat pump system with a return heat cycle, embodiments of this application also provide a computer device, which includes a memory, a processor, and a computer program stored in the memory. The processor executes the computer program to perform the aforementioned method for predicting the core temperature.

[0113] It should be understood that other functional components of the computer device can be implemented using existing technology, and therefore will not be described in detail.

[0114] In addition to the aforementioned method and apparatus for predicting the core temperature of a CO2 transcritical single-stage heat pump system with a return heat cycle, embodiments of this application also provide a computer program product, including a computer program that, when triggered by a processor, can execute the aforementioned method for predicting the core temperature.

[0115] Based on the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by hardware or by using software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of this application can be embodied in the form of a software product. This software product can be stored in a storage medium (such as CD-ROM, USB flash drive, mobile hard drive, etc.) and includes several instructions to cause a computer device (such as an in-vehicle computer or network device, etc.) to execute the warm core temperature prediction method provided in this application.

[0116] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A method for predicting the temperature of a heating core, characterized in that, The method for predicting the temperature of the heating element includes the following steps: Based on the temperature prediction coefficient θ of the heating element h The enthalpy h2 of CO2 at the compressor outlet, the enthalpy h3 of CO2 at the gas cooler outlet, and the equivalent enthalpy h of transcritical CO2 characterizing the warm core temperature. g,est The baseline value h min Determine the equivalent enthalpy h of CO2 in the transcritical region, characterizing the warm core temperature. g,est ; According to the equivalent enthalpy value h g,est and the pressure P of CO2 in the transcritical region g,hi Determine the estimated temperature T of the heating element g,est .

2. The method for predicting the temperature of the heating core according to claim 1, characterized in that, The enthalpy h2 of CO2 at the compressor outlet is based on the enthalpy h of CO2 at the compressor outlet under isentropic compression. 2,is The adiabatic efficiency η of the compressor is And the enthalpy h1 of CO2 at the compressor inlet side is determined; The enthalpy h3 of CO2 at the outlet side of the gas cooler is determined by the inlet air mass m. g The equivalent temperature difference ΔT of the heating core g CO2 mass flow rate m r And the enthalpy h2 of CO2 at the compressor outlet side is determined.

3. The method for predicting the temperature of the heating core according to claim 2, characterized in that, The enthalpy h3 of CO2 at the outlet side of the gas cooler is calculated according to formula c. g m g △T g =m r (h3-h2) is determined, where c g This is the specific heat capacity of air at constant pressure.

4. The method for predicting the temperature of the heating core according to claim 2, characterized in that, The enthalpy h of CO2 at the compressor outlet under isentropic compression 2,is Through the shaft power W of the compressor shaft The adiabatic efficiency η of the compressor is The enthalpy h1 of CO2 at the compressor inlet and the mass flow rate m of CO2. r It is determined that the shaft power W of the compressor is... shaft Through the actual power E of the compressor com and the motor efficiency η of the compressor motor Sure.

5. The method for predicting the temperature of the heating core according to claim 4, characterized in that, The mass flow rate of CO2 is determined according to the following formula: m r =η v V com ρ s ; Where, η v V is the volumetric efficiency of the compressor. com ρ is the theoretical intake capacity of the compressor. s This refers to the refrigerant density at the compressor's suction port.

6. The method for predicting the temperature of the heating core according to claim 5, characterized in that, The volumetric efficiency of the compressor is based on the formula η. v =k1-k2·P d / P s Confirmed; the motor efficiency of the compressor is based on formula η. motor =k3+k4·P d / P s Confirmed; the adiabatic efficiency of the compressor is determined according to formula η. is =k5-k6·P d / P s Sure; Among them, k1, k2, k3, k4, k5 and k6 are correction coefficients.

7. The method for predicting the temperature of the heating core according to any one of claims 2-6, characterized in that, The enthalpy h2 of CO2 at the compressor outlet is determined according to the following formula: W shaft =m r (h2-h1)=m r (h 2,is -h1) / η is .

8. The method for predicting the temperature of the heating core according to any one of claims 2-6, characterized in that, The intake air mass m g The determination is based on the actual speed or actual voltage percentage of the blower, the internal and external circulation ratio of the vehicle's air conditioning system, the ambient temperature, and the interior temperature of the vehicle. The equivalent temperature difference of the heating element is determined based on the internal and external circulation ratio of the vehicle air conditioning system, the ambient temperature, the interior temperature, the temperature of the air outlet blowing on the face, the temperature of the air outlet blowing on the feet, and the temperature of the defrost air outlet.

9. The method for predicting the temperature of the heating core according to any one of claims 1-6, characterized in that, The equivalent enthalpy value h g,est According to formula h g,est =h min +θ h (h2-h min )+(1-θ h (h) min -h3) confirmed.

10. The method for predicting the temperature of the heating core according to any one of claims 1-6, characterized in that, The benchmark value h min The temperature T of CO2 in the transcritical region g,hi enthalpy value h g,hi Sure.

11. The method for predicting the temperature of the heating core according to claim 10, characterized in that, The benchmark value h min Determined according to the following formula: 。 12. A heating core temperature prediction device, characterized in that, The heating element temperature prediction device includes: The acquisition module is used to obtain the temperature prediction coefficient θ of the heating element. h The enthalpy h2 of CO2 at the compressor outlet, the enthalpy h3 of CO2 at the gas cooler outlet, and the equivalent enthalpy h of transcritical CO2 characterizing the warm core temperature. g,est The baseline value h min And the pressure P of CO2 in the transcritical region g,hi ; The first calculation module is used to estimate the temperature coefficient θ of the heating element. h The enthalpy h2 of CO2 at the compressor outlet, the enthalpy h3 of CO2 at the gas cooler outlet, and the reference value h min Determine the equivalent enthalpy value h. g,est ; The second calculation module is used to calculate based on the equivalent enthalpy value h. g,est and the pressure P of CO2 in the transcritical region g,hi Determine the estimated temperature T of the heating element g,est .

13. A computer device comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to perform the warm core temperature prediction method according to any one of claims 1-11.

14. A computer program product, comprising a computer program, characterized in that, When the computer program is triggered to execute by the processor, it can perform the warm core temperature prediction method according to any one of claims 1-11.

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