A method for calculating the ideal specific work of an electric vehicle rotary compressor

Abstract

The application discloses a kind of electric automobile rotary compressor ideal specific work calculation method.The method includes: determining the ideal working process of electric automobile rotary compressor in three stages: 0-1 internal compression stage, 1-X isothermal mixing stage, X-2 adiabatic compression stage;Using the pV coordinate system of double offset reference plane, two interrelated pV coordinates are constructed, corresponding to 0-1 internal compression stage and X-2 adiabatic compression stage respectively, wherein the first reference plane represents internal compression in suction volume, i.e.0-1 internal compression stage is represented;The second reference plane takes the origin as the center, and represents the adiabatic compression of the total mass after mixing, i.e.X-2 adiabatic compression stage is represented, and represents the volume of the last closed cavity, which is the volume of the discharge cavity;The ideal specific work is calculated by the ideal specific work calculation model.The application can accurately represent the thermodynamic process of the compressor under actual working conditions, and conveniently obtain the ideal specific work of the compressor.

Description

Technical Field

[0001] This invention relates to the field of compressor thermodynamic analysis and structural optimization design, and particularly to the ideal specific work analysis and calculation method of electric vehicle rotary compressor and its efficiency optimization, specifically to a method for calculating the ideal specific work of an electric vehicle rotary compressor. Background Technology

[0002] Rotary compressors for electric vehicles, as positive displacement compressors that achieve compression by changing the volume of fluid space, have become key equipment in refrigeration and air conditioning fields due to their advantages such as compact structure, stable operation, and high volumetric efficiency. Therefore, calculating their ideal specific work is crucial. Ideal specific work refers to the ability of a unit mass of gas to compress from an initial pressure during an ideal, reversible, adiabatic (i.e., isentropic) compression process. Compressed to final pressure The minimum theoretical work required represents the theoretical limit of power consumption of the rotary compressor in an electric vehicle when compressing gas.

[0003] The core of calculating ideal specific work lies in the precise thermodynamic characterization of the ideal compression process of a compressor. Currently, scholars both domestically and internationally generally use the classical pV method to characterize the ideal compression process of a compressor. However, the classical pV method uses a single pV curve to depict the entire compressor's operation, failing to distinguish between the three compressor operating stages: 0-1 internal compression, 1-X isochoric mixing, and X-2 adiabatic compression. The classical pV method implicitly assumes an internal compression ratio. Equal to the overall compression ratio However, in actual operation, the internal compression ratio of the compressor... Less than the overall compression ratio Therefore, the classical pV method cannot accurately characterize the thermodynamic processes of the compressor under actual operating conditions.

[0004] Currently, there is limited research by domestic scholars on the ideal specific work of compressors. Most calculations of ideal specific work are based on the classical pV method and are superficial. Existing models are difficult to accurately describe the ideal compression process of the entire compressor and accurately calculate the ideal specific work of the compressor, which is the biggest problem at present. Summary of the Invention

[0005] In order to at least solve one of the problems existing in the prior art, this invention considers the three stages of compression process of electric vehicle rotary compressor: "0-1 internal compression loss", "1-X mixed loss" and "X-2 total mass compression loss", and establishes a method for calculating the ideal specific work of electric vehicle rotary compressor, which can conveniently obtain the ideal specific work of compressor.

[0006] To achieve the objective of this invention, a method for calculating the ideal specific work of a rotary compressor in an electric vehicle is provided, comprising the following steps: Determine the rotary compressor of the electric vehicle in The ideal working process has three stages: 0-1 internal compression stage, 1-X isochoric mixing stage, and X-2 adiabatic compression stage. In the 0-1 internal compression stage, as the rotating parts move, the gas enters the compressor through the intake port, and the intake volume gradually closes and begins to decrease, while the working fluid is adiabatically compressed in the closed chamber. In the 1-X isochoric mixing stage, the high-pressure working fluid in the discharge volume flows back to the final closed chamber, where it mixes rapidly with the low-pressure working fluid in the chamber until the pressure and temperature of the two tend to be in equilibrium. In the X-2 adiabatic compression stage, the gas is adiabatically compressed to the discharge pressure required by the system. The overall compression ratio is... Internal compression ratio; A pV coordinate system with dual offset reference planes is used to construct two interrelated pV coordinates, corresponding to the 0-1 internal compression stage and the X-2 adiabatic compression stage, respectively. The first reference plane represents the internal compression within the intake volume, i.e., the 0-1 internal compression stage; the second reference plane... The origin is used to characterize the adiabatic compression of the total mass after mixing, that is, to characterize the adiabatic compression stage of X-2. This indicates the volume of the final closed cavity. To drain the cavity volume; The ideal specific work is calculated using the ideal specific work calculation model, the expression of which is:

[0007] In the formula, To compare achievements for the ideal R is the isentropic exponent, and R is the gas constant. Inhalation temperature, To achieve equilibrium temperature after mixing, To release the air pressure inside the volume, To balance the pressure after mixing, For the quality of inhaled air, To remove the air mass from the volume.

[0008] Furthermore, the ideal working process of an electric vehicle rotary compressor satisfies three major presuppositions: The working fluid is an ideal gas; There are no leaks or frictional losses inside the machine; it is an adiabatic process. Considering only the operating condition where the overall compression ratio is greater than the internal compression ratio.

[0009] Furthermore, the volume coordinates of the dual-offset reference plane are based on the intake volume during the internal compression stage (0-1) and the total volume during the adiabatic compression stage (X-2). Using this as a baseline, while maintaining consistent pressure coordinates, we can ensure the continuity of the curve between the 0-1 internal compression stage and the X-2 adiabatic compression stage.

[0010] Furthermore, the quality of inhaled air The mass of the expelled gas is obtained by calculating the volume and density of the inhaled gas. The solution is obtained by calculating the volume and density of the discharged gas.

[0011] Furthermore, in the ideal specific work calculation model, the equilibrium temperature after mixing... Represented as:

[0012] In the formula, let ; in, The volume of the final closed cavity, The air temperature at the final closed cavity. To regulate the temperature of the air inside the volume; By changing the parameters and internal compression ratio This makes the ideal specific work calculation model applicable to various electric vehicle rotary compressors.

[0013] Furthermore, the suction volume can be optimized by changing the structural parameters of the rotary compressor in electric vehicles. Volume of the final closed cavity Discharge chamber volume To adjust the ideal specific work of the rotary compressor in electric vehicles.

[0014] Furthermore, the mechanical losses of the rotary compressor in the electric vehicle are calculated by the difference between the ideal specific work and the actual specific work.

[0015] Furthermore, the ideal specific work during the 0-1 internal compression phase is:

[0016] Furthermore, the 1-X isochoric mixing stage does not generate external boundary volume work.

[0017] Furthermore, the ideal specific work during the adiabatic compression stage of X-2 is:

[0018] The present invention also provides a system for calculating the ideal specific work of a rotary compressor for an electric vehicle.

[0019] The present invention also provides a computer device.

[0020] The present invention also provides a computer-readable storage medium.

[0021] Compared with the prior art, the present invention has the following positive effects: 1) The established calculation model balances rigor and simplicity, has high calculation accuracy, and can accurately reflect the thermodynamic characteristics of the ideal working process of the rotary compressor of electric vehicles.

[0022] 2) The model parameters are easy to adjust and can be adapted to different types of electric vehicle rotary compressors (scroll, screw, etc.), providing rich simulation data to support the analysis of influencing factors.

[0023] 3) This calculation method can accurately correlate compressor structural parameters with ideal specific work, providing a reliable reference for thermodynamic optimization and structural design improvement of electric vehicle rotary compressors, and helping to improve compressor efficiency. Attached Figure Description

[0024] Figure 1 This is a diagram illustrating the ideal three-stage compression process of a rotary compressor in an electric vehicle, represented by the classic pV characterization.

[0025] Figure 2 This is an idealized schematic diagram of a typical rotary compressor.

[0026] Figure 3 This diagram illustrates the ideal three-stage compression process of an electric vehicle rotary compressor, based on the pV characterization of a dual-offset reference plane.

[0027] Figure 4 This is a schematic diagram illustrating the steps involved in calculating the ideal specific work of a rotary compressor in an electric vehicle. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Figure 2 The left side is the system input, the left side is... This is the enthalpy value during the inhalation phase. This represents the mechanical work input to the system. (Inside the block diagram) This refers to the compressor itself, which consumes mechanical work from the external system and draws in external enthalpy value. The gas; Indicates the exclusion of volume; This represents an ideal automatic valve, assuming that after mixing occurs, the ideal automatic valve... Close to prevent gas backflow; This indicates a regulating valve, used to control the system's exhaust back pressure and to control the volume of gas. This represents the enthalpy in the exhaust state. The entire system is a control volume model of an ideal rotary compressor system.

[0030] This invention provides a method for calculating the ideal specific work of a rotary compressor for an electric vehicle, comprising the following steps: Step 1: Define the ideal working process of the rotary compressor for electric vehicles (existing technologies generally use the "classical pV characterization method," which cannot distinguish the three stages emphasized in this embodiment: "0-1 internal compression," "1-X isochoric mixing," and "X-2 adiabatic compression"): The ideal process of the rotary compressor for electric vehicles needs to meet three prerequisites: a) the working fluid is an ideal gas; b) there is no leakage or friction loss inside the machine, and it is an adiabatic process; c) only the operating conditions are considered. That is, the overall compression ratio > Internal compression ratio For the pressure at the inlet state, The pressure at the end of the internal compression state.

[0031] The rotary compressor for electric vehicles has an ideal three-stage working process: Phase 1: Internal Compression in Phase 0-1 Gas enters the compressor's suction volume through the intake port. As the rotating components move, the suction volume gradually closes and begins to decrease, and the working fluid is adiabatically compressed within the closed chamber.

[0032] Phase Two: Isochoric Mixing in Phases 1-X When the volume of the compression chamber decreases to At that time, the internal structure of the compressor makes the final stage closed chamber (volume) ,pressure ) and discharge volume (Including exhaust pipes, gas storage tanks, downstream system volume, etc., discharge pressure) ) connected. Due to ( ), discharge volume The high-pressure working fluid inside will instantly flow back to the final closed chamber, where it will mix with the low-pressure working fluid (using...) inside the chamber. (This refers to the mass of the low-pressure working fluid) undergoes rapid mixing until the pressure and temperature of the two substances tend to reach equilibrium.

[0033] Third stage: X-2 stage adiabatic compression After the mixing process is complete, the rotating component continues to move, increasing the total volume after mixing. Further reduction occurs as the gas is adiabatically compressed to the system's required discharge pressure. Finally, it is discharged through the exhaust port to the discharge volume. .

[0034] Step 2: Identify the limitations of classical pV characterization. The single curve of classical pV characterization cannot distinguish between "0-1 internal compression loss," "1-X mixed loss," and "X-2 total mass compression loss," and can only calculate the total mass compression work. This invention establishes a new pV characterization method (dual-offset reference plane): the "dual-offset reference plane" accurately characterizes the two adiabatic compression stages (0-1 stage and X-2 stage) through two interrelated pV coordinates, as specifically designed below: Please see Figure 3 First reference plane (pOv): characterizes the internal compression during the 0-1 phase. With "inhalation volume" The reference origin O is the volume axis (V-axis), and the pressure axis (p-axis) is the absolute pressure coordinate. This first reference plane only characterizes the internal compression process of the low-pressure working fluid being drawn in; the area under the 0-1-X-2 curve corresponds to the compression work in the 0-1 stage. , This represents the specific volume of the gas in the 0-1 stage.

[0035] Second reference plane (p-O'-v'): Characterizes adiabatic compression in the X-2 stage. With "total mixed volume" "" represents the offset point O' of the volume axis (V' axis), meaning the actual volume value of the V' axis is... , The reference zero point representing the new coordinate system, Representing the volume of relative change in the new coordinate system, the pressure axis (p-axis) is completely aligned with the first reference plane, which only characterizes the total mass. The adiabatic compression process, the area under the curve corresponds to the compression work in stage X-2. ,in . V represents the specific volume of the gas in stage X-2; V represents the instantaneous absolute volume within the closed working chamber of the compressor rotor.

[0036] Step 3: Derivation of the accurate formula for calculating ideal specific work: The new formula for calculating ideal specific work is derived based on the new pV characterization method, the first law of thermodynamics, and the working conditions described in Step 1.

[0037] a) Internal compression in stage 0-1: The thermodynamic expression is:

[0038] The derivation process is as follows: Isoentropy process:

[0039] in

[0040] Substitution :

[0041] Integral of work:

[0042] Specific heat capacity at constant volume; : Pressure at the inlet.

[0043] b) Isochoric mixing in stage 1-X: Isochoric compression does not produce work on the external boundary volume, but it does result in a redistribution of internal energy. and Use it in the formula in the next stage.

[0044]

[0045]

[0046] ; c) X-2 stage adiabatic compression The thermodynamic equation is:

[0047] The derivation process is as follows: Isoentropy process:

[0048] ,

[0049] Total work integral for X-2 stage:

[0050] ,

[0051] Substitution :

[0052] in:

[0053] Isentropic ideal gas:

[0054] Substituting, we get:

[0055] The specific work of X-2 is:

[0056] The ideal specific work calculation model is as follows:

[0057] In the formula: It is the isentropic exponent. The gas constant is For isobaric specific heat capacity, Inhalation temperature, This refers to the temperature after the internal compression phase ends. Internal compression ratio, To achieve equilibrium temperature after mixing, The compression ratio for stage X-2. For the quality of inhaled air, To remove the air mass from the volume, The air pressure at the final closed small cavity. This refers to the air volume of the final closed cavity, i.e., the volume of the last closed cavity. The air temperature at the final closed cavity. To release the air pressure inside the volume, To drain the cavity volume, To release the temperature of the air inside the volume, To balance the pressure after mixing.

[0058] This ideal specific work calculation model can be used as a performance benchmark for electric vehicle rotary compressors, and as a basic input for structural parameter optimization, operating condition matching analysis, or complex loss models.

[0059] In one embodiment, the mechanical losses of the rotary compressor in an electric vehicle can be accurately calculated using the difference between the ideal specific work and the actual specific work.

[0060] In one embodiment, the suction volume is optimized by changing the structural parameters of the electric vehicle rotary compressor. Volume of the final closed cavity Discharge chamber volume (By optimizing the structural parameters of the scroll compressor), the ideal specific work of the electric vehicle rotary compressor is adjusted to improve the thermodynamic efficiency of the electric vehicle rotary compressor.

[0061] In one embodiment, the inhaled gas density and the density of the expelled gas From the ideal gas equation The solution yields the mass of the inhaled gas. Due to the volume of inhaled gas and inhaled gas density The solution yields the mass of the discharged gas. From the volume of the discharged gas and exhaust gas density The solution yields the following formula: .

[0062] In one embodiment, by changing the parameters and This makes the ideal specific work calculation model applicable to various electric vehicle rotary compressors.

[0063] In one embodiment, a system for calculating the ideal specific work of a rotary compressor in an electric vehicle is provided for implementing the method described in the foregoing embodiments. The system includes the following modules: The ideal working process stage segmentation module is used to determine the stage of operation of the rotary compressor in electric vehicles. The ideal working process has three stages: 0-1 internal compression stage, 1-X isochoric mixing stage, and X-2 adiabatic compression stage. In the 0-1 internal compression stage, as the rotating parts move, the gas enters the compressor through the intake port, and the intake volume gradually closes and begins to decrease, while the working fluid is adiabatically compressed in the closed chamber. In the 1-X isochoric mixing stage, the high-pressure working fluid in the discharge volume flows back to the final closed chamber, where it mixes rapidly with the low-pressure working fluid in the chamber until the pressure and temperature of the two tend to be in equilibrium. In the X-2 adiabatic compression stage, the gas is adiabatically compressed to the discharge pressure required by the system. The overall compression ratio is... Internal compression ratio; The compression stage characterization module uses a pV coordinate system with dual offset reference planes to construct two interrelated pV coordinates, corresponding to the 0-1 internal compression stage and the X-2 adiabatic compression stage, respectively. The first reference plane characterizes the internal compression within the intake volume, i.e., the 0-1 internal compression stage; the second reference plane... The origin is used to characterize the adiabatic compression of the total mass after mixing, that is, to characterize the adiabatic compression stage of X-2. This indicates the volume of the final closed cavity. To drain the cavity volume; The ideal specific work calculation model module is used to calculate the ideal specific work through the ideal specific work calculation model, the expression of which is:

[0064] In the formula, To compare achievements for the ideal R is the isentropic exponent, and R is the gas constant. Inhalation temperature, To achieve equilibrium temperature after mixing, To release the air pressure inside the volume, To balance the pressure after mixing, For the quality of inhaled air, To remove the air mass from the volume.

[0065] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the methods described in the foregoing embodiments.

[0066] In one embodiment, a computer-readable storage medium is provided, the computer-readable storage medium storing a number of... A computer program that, when executed by a processor, implements the methods described in the foregoing embodiments.

[0067] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined in this invention may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for calculating the ideal specific work of a rotary compressor for an electric vehicle, characterized in that, Includes the following steps: Determine the rotary compressor of the electric vehicle in The ideal working process has three stages: 0-1 internal compression stage, 1-X isochoric mixing stage, and X-2 adiabatic compression stage. In the 0-1 internal compression stage, as the rotating parts move, the gas enters the compressor through the intake port, and the intake volume gradually closes and begins to decrease, while the working fluid is adiabatically compressed in the closed chamber. In the 1-X isochoric mixing stage, the high-pressure working fluid in the discharge volume flows back to the final closed chamber, where it mixes rapidly with the low-pressure working fluid in the chamber until the pressure and temperature of the two tend to be in equilibrium. In the X-2 adiabatic compression stage, the gas is adiabatically compressed to the discharge pressure required by the system. The overall compression ratio is... Internal compression ratio; A pV coordinate system with dual offset reference planes is used to construct two interrelated pV coordinates, corresponding to the 0-1 internal compression stage and the X-2 adiabatic compression stage, respectively. The first reference plane represents the internal compression within the intake volume, i.e., the 0-1 internal compression stage; the second reference plane... The origin is used to characterize the adiabatic compression of the total mass after mixing, that is, to characterize the adiabatic compression stage of X-2. This indicates the volume of the final closed cavity. To drain the cavity volume; The ideal specific work is calculated using the ideal specific work calculation model, the expression of which is: In the formula, To compare achievements for the ideal R is the isentropic exponent, and R is the gas constant. Inhalation temperature, To achieve equilibrium temperature after mixing, To release the air pressure inside the volume, To balance the pressure after mixing, For the quality of inhaled air, To remove the air mass from the volume.

2. The method for calculating the ideal specific work of an electric vehicle rotary compressor according to claim 1, characterized in that, The ideal working process of a rotary compressor in an electric vehicle satisfies three major presuppositions: The working fluid is an ideal gas; There are no leaks or frictional losses inside the machine; it is an adiabatic process. Considering only the operating condition where the overall compression ratio is greater than the internal compression ratio.

3. The method for calculating the ideal specific work of an electric vehicle rotary compressor according to claim 1, characterized in that, The volumetric coordinates of the dual-offset reference plane are based on the intake volume during the internal compression phase (0-1) and the total volume during the adiabatic compression phase (X-2). Use this as a reference, while maintaining consistency in the pressure coordinates.

4. The method for calculating the ideal specific work of an electric vehicle rotary compressor according to claim 1, characterized in that, Inhaled air quality The mass of the expelled gas is obtained by calculating the volume and density of the inhaled gas. The solution is obtained by calculating the volume and density of the discharged gas.

5. The method for calculating the ideal specific work of an electric vehicle rotary compressor according to claim 1, characterized in that, In the ideal specific work calculation model, the equilibrium temperature after mixing Represented as: In the formula, let ; in, The volume of the final closed cavity. The air temperature at the final closed cavity. To regulate the temperature of the air inside the volume; By changing the parameters and internal compression ratio This makes the ideal specific work calculation model applicable to various electric vehicle rotary compressors.

6. The method for calculating the ideal specific work of an electric vehicle rotary compressor according to claim 1, characterized in that, By changing the structural parameters of the rotary compressor in an electric vehicle, the suction volume can be optimized. Volume of the final closed cavity Discharge chamber volume To adjust the ideal specific work of the rotary compressor in electric vehicles.

7. A method for calculating the ideal specific work of an electric vehicle rotary compressor according to any one of claims 1-6, characterized in that, The mechanical losses of the rotary compressor in an electric vehicle are calculated by the difference between the ideal specific work and the actual specific work.

8. A system for calculating the ideal specific work of a rotary compressor for an electric vehicle, characterized in that, The system for implementing the method according to any one of claims 1-7 includes the following modules: The ideal working process stage segmentation module is used to determine the stage of operation of the rotary compressor in electric vehicles. The ideal working process has three stages: 0-1 internal compression stage, 1-X isochoric mixing stage, and X-2 adiabatic compression stage. In the 0-1 internal compression stage, as the rotating parts move, the gas enters the compressor through the intake port, and the intake volume gradually closes and begins to decrease, while the working fluid is adiabatically compressed in the closed chamber. In the 1-X isochoric mixing stage, the high-pressure working fluid in the discharge volume flows back to the final closed chamber, where it mixes rapidly with the low-pressure working fluid in the chamber until the pressure and temperature of the two tend to be in equilibrium. In the X-2 adiabatic compression stage, the gas is adiabatically compressed to the discharge pressure required by the system. The overall compression ratio is... Internal compression ratio; The compression stage characterization module uses a pV coordinate system with dual offset reference planes to construct two interrelated pV coordinates, corresponding to the 0-1 internal compression stage and the X-2 adiabatic compression stage, respectively. The first reference plane characterizes the internal compression within the intake volume, i.e., the 0-1 internal compression stage; the second reference plane... The origin is used to characterize the adiabatic compression of the total mass after mixing, that is, to characterize the adiabatic compression stage of X-2. This indicates the volume of the final closed cavity. To drain the cavity volume; The ideal specific work calculation model module is used to calculate the ideal specific work through the ideal specific work calculation model, the expression of which is: In the formula, To compare achievements for the ideal R is the isentropic exponent, and R is the gas constant. Inhalation temperature, To achieve equilibrium temperature after mixing, To release the air pressure inside the volume, To balance the pressure after mixing, For the quality of inhaled air, To remove the air mass from the volume.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method according to any one of claims 1-7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method described in any one of claims 1-7.

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