Vehicle cabin air boosting device and design method based on engine exhaust turbine kinetic energy

Abstract

The present invention provides a vehicle cabin air boosting device and design method based on the kinetic energy of an engine exhaust turbine. The boosting device includes a second-stage supercharger turbine, a second-stage supercharger turbine end regulating valve, a second-stage supercharger intercooler, a booster cabin regulating valve, a second-stage supercharger compressor regulating valve, a booster cabin, and a second-stage supercharger compressor. The second-stage supercharger turbine is connected to the exhaust port of the engine's first supercharger turbine. The second-stage turbine end regulating valve is connected in parallel to both ends of the second-stage supercharger turbine. The turbine shaft of the second-stage supercharger turbine is connected to the second-stage supercharger compressor. The second-stage supercharger compressor regulating valve is connected in parallel to both ends of the second-stage supercharger compressor. The high-pressure air output pipeline of the second-stage supercharger compressor is connected to the booster cabin. The booster cabin regulating valve and the second-stage supercharger intercooler are disposed on the high-pressure air output pipeline. This device can solve the problem of boosting cabin air in vehicles operating in high altitude areas and overcome altitude sickness.

Description

Technical Field

[0001] The present invention belongs to the technical field of air supercharging, and in particular relates to a vehicle cabin air supercharging device and a design method based on the kinetic energy of an engine exhaust turbine. Background Art

[0002] Due to the high altitude and thin air, vehicles traveling on the plateau can easily cause breathing difficulties for drivers and passengers. To overcome altitude sickness, such as breathing difficulties, the air in the vehicle cabin needs to be pressurized. Currently, vehicle cabin pressurization methods mainly rely on devices such as high-pressure fans and air compressors. However, the use of these devices brings the following problems: first, they require additional power to drive the vehicle; second, the weight of the equipment increases the vehicle's curb weight; third, the pressurization equipment requires a large amount of vehicle space; and fourth, the pressurization equipment generates a lot of noise during operation, seriously affecting the passenger comfort. Therefore, there is an urgent need to develop energy-saving and environmentally friendly methods and technologies for pressurizing vehicle cabin air. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects of the existing technology, to solve the problem of air pressurization in the cabin of plateau vehicles and overcome altitude sickness, and to propose a vehicle cabin air pressurization device and design method based on the kinetic energy of the engine exhaust turbine.

[0004] The method of the present invention is achieved through the following technical solutions:

[0005] In one aspect, the present application provides a vehicle cabin air supercharging device based on the kinetic energy of an engine exhaust turbine, comprising: a second-stage supercharger turbine, a second-stage supercharger turbine end regulating valve, a second-stage supercharger intercooler, a supercharger cabin regulating valve, a second-stage supercharger compressor regulating valve, a supercharger cabin, and a second-stage supercharger compressor;

[0006] The second-stage supercharger turbine is used to connect to the exhaust port of the first supercharger turbine of the engine. The second-stage turbine end regulating valve is connected in parallel to the two ends of the second-stage supercharger turbine. The turbine shaft of the second-stage supercharger turbine is connected to the second-stage supercharger compressor. The second-stage supercharger compressor regulating valve is connected in parallel to the two ends of the second-stage supercharger compressor. The high-pressure air output pipeline of the second-stage supercharger compressor is connected to the supercharger cabin. The supercharger cabin regulating valve and the second-stage supercharger intercooler are arranged on the high-pressure air output pipeline.

[0007] Furthermore, the parameters of the second-stage supercharger press of the present invention include:

[0008] Impeller inlet area F1 design:

[0009]

[0010] Where ρ1 is the air density at the impeller inlet, c 1ais the axial velocity of the airflow at the impeller inlet, G c is the engine intake air mass flow rate;

[0011] Impeller inlet outer diameter D1:

[0012]

[0013] Where: D0 is the outer diameter of the impeller hub at the inlet;

[0014] Impeller outlet diameter D2:

[0015]

[0016] Impeller outlet width b2:

[0017]

[0018] Among them, τ2 is the blockage coefficient at the impeller outlet, ρ2 is the air density at the impeller outlet, c 2r is the radial component of the absolute velocity at the outer edge of the impeller diameter;

[0019] Compressor volute outlet area A y :

[0020]

[0021] Where ρ5 is the gas density at the compressor volute outlet, c y is the air velocity at the compressor volute outlet.

[0022] Furthermore, the parameters of the second-stage supercharger turbine of the present invention include:

[0023]

[0024] in, is the turbine mass flow rate; p4 is the exhaust pressure after the turbine; p3 is the exhaust pressure before the turbine; κ3 is the turbine constant entropy index, μ T is the turbine circumferential speed, and ρ3 is the exhaust gas density before the turbine.

[0025] In another embodiment of the present application, the parameters of the intercooler are:

[0026] 1) Equivalent diameter De is:

[0027] ①Cold side:

[0028]

[0029] Where: x W and y W They are the inner distance and inner height of the fin on the cold side of the radiator respectively;

[0030] ②Hot side:

[0031]

[0032] Where: x b and y b are the inner distance and inner height of the radiator hot side fin respectively;

[0033] 2) The flow cross-sectional area F is:

[0034] ①Cold side flow cross-sectional area F w

[0035]

[0036] Among them, B w is the effective width of the cold side, S w is the cold side fin spacing, n is the number of cooling tubes;

[0037] ②Hot side flow cross-sectional area F b

[0038]

[0039] Among them, S b is the hot side fin spacing, B b is the effective width of the hot side;

[0040] (3) Intercooler cooling area is:

[0041] 1) Calculation of actual heat dissipation area

[0042] ①Cold side heat dissipation area A w

[0043]

[0044] Among them, L w is the effective length of the cold side, x W is the inner distance of the cold side wing, y W The inner side of the cold side wing is high;

[0045] ②Hot side heat dissipation area A b

[0046]

[0047] Among them, L b is the effective length of the hot side, x b is the inner distance of the cold side wing, y b The inner side of the wing is higher on the cold side.

[0048] ③Total heat dissipation area A:

[0049] A=A w +A b

[0050] 2) Minimum heat dissipation area A required for charge air cooling C for:

[0051]

[0052] Among them, G mb is the hot air flow after supercharging, K is the heat transfer coefficient of the intercooler, ΔT n It is the difference between the inlet and outlet temperatures of the intercooler (℃).

[0053] And the actual heat dissipation area A of the intercooler is greater than A C .

[0054] On the other hand, the present application provides a design method for a vehicle cabin air boosting device based on the kinetic energy of the engine exhaust turbine, the specific process of which is as follows:

[0055] Establish a supercharged engine thermodynamic simulation model to obtain the internal combustion engine intake mass flow rate at different sea wave heights;

[0056] Calculate the second-stage supercharger turbine intake volume and the air bleed rate of the second-stage supercharger turbine end regulating valve at different altitudes based on the input supercharger cabin pressure, supercharger cabin air flow rate, and supercharger cabin air density;

[0057] Calculating the parameters of the second-stage turbocharger turbine, designing the second-stage turbocharger compressor according to the internal combustion engine intake air mass flow rate, and calculating the parameters of the second-stage intercooler;

[0058] The second-stage turbine end regulating valve is connected in parallel to both ends of the second-stage supercharger turbine, the turbine shaft of the second-stage supercharger turbine is connected to the second-stage supercharger compressor, and a second-stage supercharger compressor regulating valve is set in parallel at both ends of the second-stage supercharger compressor. The high-pressure air output pipeline of the second-stage supercharger compressor is connected to the supercharger cabin, and the supercharger cabin regulating valve and the second-stage supercharger intercooler are set on the high-pressure air output pipeline.

[0059] Furthermore, when the total heat dissipation area A of the intercooler is less than the minimum heat dissipation area A required for the charge air cooling C When the intercooler is turned off, adjust the design parameters of the intercooler until its total heat dissipation area A is greater than or equal to A C

[0060]

[0061] Among them, G mb is the hot air flow after supercharging, K is the heat transfer coefficient of the intercooler, ΔT n It is the difference between the inlet and outlet temperatures of the intercooler (℃).

[0062] Beneficial effects

[0063] First, the second-stage supercharger turbine of the supercharging device of the present invention can use the exhaust gas discharged by the first supercharger turbine of the engine to drive the turbine rotor shaft to rotate. At the same time, the second-stage supercharger compressor fixed at the other end of the turbine rotor shaft compresses and pressurizes the incoming air under the drive of the turbine rotor shaft, and transports the pressurized air to the supercharged cabin, so that the air in the vehicle cabin can be maintained at a normal pressure level in a plateau environment; the supercharging device is suitable for use at various altitudes, has a simple and compact structure, is light in weight, and has low vibration and noise.

[0064] Secondly, the second-stage supercharger turbine of the power generation device of the present invention can use the kinetic energy of the exhaust gas discharged by the first supercharger turbine of the engine to drive the rotation of its turbine rotor shaft, thereby achieving the requirements of low carbon and green environmental protection.

[0065] Third, the supercharging device developed by the present invention can be directly used on motor vehicles at different altitudes in my country after only slight modifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0067] Figure 1 Schematic diagram of a vehicle cabin air boosting device based on engine exhaust gas turbine kinetic energy according to an embodiment of the present invention;

[0068] Figure 2 Design a flow chart for a vehicle cabin air boosting device based on the kinetic energy of the engine exhaust gas turbine;

[0069] Figure 3 is the air intake volume of the second-stage supercharger turbine at different altitudes;

[0070] Figure 4 is the air bleed rate of the exhaust turbine bypass valve of the second-stage turbocharger at different altitudes. DETAILED DESCRIPTION

[0071] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0072] It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments may be combined with each other; and, based on the embodiments in this disclosure, all other embodiments obtained by persons of ordinary skill in the art without creative work are within the scope of protection of this disclosure.

[0073] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this disclosure, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0074] On the one hand, the embodiment of the present application provides a vehicle cabin air boosting device based on the kinetic energy of the engine exhaust turbine, such as Figure 1 As shown, it includes: a second-stage supercharger turbine 1, a second-stage supercharger turbine end regulating valve 2, a second-stage supercharger intercooler 8, a pressurization cabin regulating valve 9, a second-stage supercharger compressor regulating valve 10, a pressurization cabin 11 and a second-stage supercharger compressor 12; Figure 1 The first-stage supercharger turbine 3, the first-stage supercharger turbine bypass valve 4, the internal combustion engine 5, the first-stage supercharger intercooler 6, the first-stage supercharger compressor 7, and the pressurized cabin 11 are components already present in the motor vehicle.

[0075] The second-stage supercharger turbine 1 is used to connect to the exhaust port of the first supercharger turbine of the engine. The second-stage turbine end regulating valve 2 is connected in parallel to the two ends of the second-stage supercharger turbine 1. The turbine shaft of the second-stage supercharger turbine 1 is connected to the second-stage supercharger compressor 12. The second-stage supercharger compressor regulating valve 10 is connected in parallel to the two ends of the second-stage supercharger compressor 12. The high-pressure air output pipeline of the second-stage supercharger compressor 12 is connected to the booster cabin 11. The booster cabin regulating valve 9 and the second-stage supercharger intercooler 8 are arranged on the high-pressure air output pipeline.

[0076] In this embodiment, the second-stage turbocharger (including the turbine 1 and the impeller 12) uses the kinetic energy of the exhaust gas generated by the first-stage turbocharger to drive its rotor to rotate, and performs work on the second-stage compressor impeller (impeller 12) to generate pressurized gas, which is then appropriately cooled by the intercooler 8 and supplied to the pressurization chamber 11.

[0077] In another embodiment of the present application, the parameters for designing the second-stage supercharger compressor include:

[0078] Impeller inlet area F1 design:

[0079]

[0080] Where ρ1 is the air density at the impeller inlet, c 1ais the axial velocity of the airflow at the impeller inlet, G c is the engine intake air mass flow rate;

[0081] Impeller inlet outer diameter D1:

[0082]

[0083] Where: D0 is the outer diameter of the impeller hub at the inlet;

[0084] Impeller outlet diameter D2:

[0085]

[0086] Impeller outlet width b2:

[0087]

[0088] Where τ2 is the blockage coefficient at the impeller outlet, ρ2 is the air density at the impeller outlet, D2 is the impeller outlet diameter, and the compressor volute outlet area A is y :

[0089]

[0090] Where ρ5 is the gas density at the compressor volute outlet, c y is the air velocity at the compressor volute outlet.

[0091] In another embodiment of the present application, the parameters for designing the second-stage supercharger turbine include:

[0092]

[0093] in, is the turbine mass flow rate; p4 is the exhaust pressure after the turbine; p3 is the exhaust pressure before the turbine; κ3 is the turbine constant entropy index, μ T is the turbine peripheral speed.

[0094] Another embodiment of the present application designs an intercooler, and the specific process is as follows:

[0095] 1) Calculation of equivalent diameter De

[0096] ①Cold side:

[0097]

[0098] Where: x W and y W They are the inner distance and inner height of the cold side fin of the radiator respectively.

[0099] ②Hot side:

[0100]

[0101] Where: x b and y b They are the inner distance and inner height of the radiator thermal side fins respectively.

[0102] 2) Calculation of flow cross-sectional area F

[0103] ①Cold side flow cross-sectional area F w

[0104]

[0105] Among them, B w is the effective width of the cold side, S w is the cold side fin spacing, and n is the number of cooling tubes.

[0106] ②Hot side flow cross-sectional area F b

[0107]

[0108] Among them, S b is the hot side fin spacing, B b is the effective width of the hot side;

[0109] (3) Intercooler heat dissipation area verification formula:

[0110] 1) Calculation of actual heat dissipation area

[0111] ①Cold side heat dissipation area A w

[0112]

[0113] Among them, L w is the effective length of the cold side, x W is the inner distance of the cold side wing, y W The inner side of the wing is higher on the cold side.

[0114] ②Hot side heat dissipation area A b

[0115]

[0116] Among them, L b is the effective length of the hot side, x b is the inner distance of the cold side wing, y b The inner side of the wing is higher on the cold side.

[0117] ③Total heat dissipation area A:

[0118] A=A w +A b

[0119] 2) Minimum heat dissipation area A required for charge air coolingC :

[0120]

[0121] If the actual heat dissipation area A of the intercooler is greater than A C , the intercooler heat dissipation area calibration is qualified, and the designed intercooler meets the cooling index requirements; otherwise, the above intercooler design parameters need to be modified to meet the cooling requirements.

[0122] The embodiment of the present application provides a method for designing a vehicle cabin air boosting device based on the kinetic energy of the engine exhaust turbine. Figure 2 As shown, the specific process is:

[0123] Step 1: Use GT-POWER software to establish a supercharged engine thermodynamic simulation model;

[0124] Step 2: Calculate the intake mass flow and exhaust mass flow of the internal combustion engine at different altitudes based on the input altitude parameters and engine parameters, such as Figure 3 As shown;

[0125] Step 3: Based on the input parameters such as the pressurized cabin pressure, pressurized cabin air flow, and pressurized cabin air density, calculate the second-stage supercharger turbine intake volume and the second-stage supercharger turbine end regulating valve (i.e., bypass valve) bleed rate at different altitudes, such as Figure 4 As shown;

[0126] Step 4: Complete the second-stage supercharger design, including: (1) compressor pressure ratio calculation; (2) compressor main thermodynamic parameter calculation; (3) compressor main parameter calculation; (4) turbine main thermodynamic parameter calculation; (5) turbine main parameter calculation. The specific process is as follows:

[0127] (1) Second stage turbocharger compressor pressure ratio parameters:

[0128]

[0129] Where: π c is the pressure ratio; p c is the compressor outlet pressure, kPa; p0 is the compressor inlet pressure, kPa.

[0130] (2) Calculation of the main thermodynamic parameters of the second-stage turbocharger compressor:

[0131] 1) Compressor adiabatic work H C :

[0132]

[0133] Where: T0 is the compressor inlet temperature, k is the constant entropy index, k = 1.4; pc is the compressor outlet pressure.

[0134] 2) Compressor power consumption N K :

[0135]

[0136] in: is the air flow through the compressor; η K is the compressor isentropic efficiency; η mK is the mechanical efficiency of the compressor; κ1 is the constant entropy index of the compressor; and the air temperature before the impeller is T1.

[0137] (3) Calculation of main parameters of the second-stage turbocharger compressor:

[0138] 1) Impeller outlet circumferential speed V2:

[0139]

[0140] in: is the pressure head coefficient.

[0141] 2) Axial velocity of airflow at impeller inlet c 1a :

[0142]

[0143] in: is the compressor flow coefficient.

[0144] 3) Air temperature before impeller T1:

[0145]

[0146] 4) Air pressure p1 at the impeller inlet:

[0147]

[0148] Among them, n1 is the variable index at the impeller inlet.

[0149] 5) Air density ρ1 at the impeller inlet:

[0150]

[0151] Where: R is the gas constant.

[0152] 6) Impeller inlet area F1:

[0153]

[0154] Among them: G c is the engine intake air mass flow rate, kg / s.

[0155] 7) Impeller inlet outer diameter D1:

[0156]

[0157] Where: D0 is the outer diameter of the impeller hub at the impeller inlet.

[0158] 8) Impeller outlet diameter D2:

[0159]

[0160] 9) Average diameter D at impeller inlet 1m :

[0161]

[0162] 10)D 1m Circumferential speed v at diameter 1m :

[0163]

[0164] 11) Impeller outlet slip coefficient μ:

[0165]

[0166] Where: 2B is the backward bending angle of the impeller outlet, Z c is the number of leaves.

[0167] 12) Impeller inlet blocking coefficient τ1:

[0168]

[0169] Where: δ1 is the thickness of the blade rim at the inlet.

[0170] 13) Circumferential velocity v1 at impeller inlet D1:

[0171]

[0172] 14) Consider the axial velocity c1' at the inlet after blocking a :

[0173]

[0174] Among them, τ1 is the impeller inlet blocking coefficient.

[0175] 15)D 1m Relative velocity v D1m :

[0176]

[0177] 16) Airflow angle β1 at the impeller inlet outer diameter:

[0178]

[0179] 17) Airflow angle of attack i at D1:

[0180] i=β 1b -β1 (20)

[0181] Where: 1b is the blade installation angle at D1.

[0182] 18) Impeller outlet air temperature T2:

[0183]

[0184] Where: α is the friction coefficient of the wheel.

[0185] 19) Impeller outlet gas pressure p2:

[0186]

[0187] Where: n2 is the variable index in the impeller.

[0188] 20) Impeller outlet air density ρ2:

[0189]

[0190] 21) Blockage coefficient τ2 at impeller outlet:

[0191]

[0192] Where: δ2 is the thickness of the impeller outlet blade rim.

[0193] 22) Impeller outlet width b2:

[0194]

[0195] Among them, c 2r It is the radial component of the absolute velocity at the outer edge of the impeller diameter.

[0196] 23) Absolute air velocity c2 at D2:

[0197]

[0198] 24) Airflow angle α2:

[0199]

[0200] 25) Relative air velocity w2 at D2:

[0201]

[0202] 26) Vaneless diffuser outlet diameter D4:

[0203] D4=D2ε (29)

[0204] Where: ε is the wheel diameter ratio.

[0205] 27) Bladeless diffuser outlet air velocity c4:

[0206]

[0207] 28) Vaneless diffuser outlet temperature T4:

[0208]

[0209] 29) Vaneless diffuser outlet pressure p4:

[0210]

[0211] Where: n3 is the diffuser polytropic index.

[0212] 30) Compressor volute outlet temperature T5:

[0213]

[0214] Where: c y is the air velocity at the compressor volute outlet.

[0215] 31) Compressor volute outlet pressure p5:

[0216]

[0217] Among them: n4 is the volute variable index.

[0218] 32) Gas density at compressor volute outlet ρ5:

[0219]

[0220] 33) Compressor volute outlet area A y :

[0221]

[0222] 34) Compressor volute outlet diameter D y :

[0223]

[0224] (4) Calculation of the main thermodynamic parameters of the second-stage turbocharger turbine;

[0225] 1) Turbine expansion ratio π T :

[0226]

[0227] Where: π c is the compressor pressure ratio; T4 is the exhaust gas temperature after the turbine; T3 is the exhaust gas temperature before the turbine; η TC is the total efficiency of the supercharger.

[0228] 2) Turbine output power N T :

[0229]

[0230] in: is the turbine mass flow rate; p4 is the exhaust pressure after the turbine; p3 is the exhaust pressure before the turbine; R is the gas constant; κ3 is the turbine constant entropy index.

[0231] (5) Calculation of main operating parameters of the second-stage turbocharger turbine

[0232] 1) Turbine geometric flow section A T :

[0233]

[0234] Where: μ T is the turbine circumferential speed, and ρ3 is the exhaust gas density before the turbine.

[0235] Step 5: Calculate the MAP characteristic curve of the second-stage supercharger at different altitudes;

[0236] The MAP characteristic of the supercharger refers to the performance parameter of the compressor (compression ratio π K , isentropic efficiency η K etc.) and operating parameters (turbine mass flow Supercharger speed n K , the relationship curve between the compressor inlet pressure p1 and the compressor inlet temperature T1) is expressed as follows:

[0237]

[0238] The second-stage turbocharger compressor parameters (p1, T1) used at different altitudes are used as the inlet conditions for the calculation, and then the numerical simulation method is used to solve the equation group (41), and more than 6 groups of turbine mass flow are obtained. The horizontal axis and the pressure ratio π K The data is taken as the vertical axis, and then the MAP characteristic curve of the supercharger is drawn using MATLAB. This curve is used as the performance verification curve of the turbocharger manufacturer.

[0239] Step 6: Calculate the heat dissipation of the pressurized air of the second-stage supercharger compressor at different altitudes by comparing the inputted pressurized cabin air temperature adjustment index parameter;

[0240] Q X =G C C Pb (T 1T -T 2T ) (42)

[0241] Among them, G c is the second stage boost air flow; C Pb is the specific heat capacity at constant pressure, C Pb =1.009KJ / kg℃;T b1 and T b2 are the inlet and outlet temperatures of the second-stage turbocharger intercooler, respectively.

[0242] Step 7: Complete the intercooler design for the second-stage supercharger, including: (1) calculation of the intercooler's heat dissipation capacity; (2) calculation of the intercooler's geometric parameters; and (3) verification of the intercooler's heat dissipation area. The specific process is as follows:

[0243] (1) Calculation formula for intercooler heat dissipation capacity matching:

[0244] 1) Calculation of the cooling medium (cold side air) temperature out of the intercooler

[0245] Calculate the temperature t of the cooling medium leaving the intercooler according to the heat balance equation w2 :

[0246] G mb ×C pb (t b1 -t b2 )=G ma ×C pa (T w1 -T w2 ) (43)

[0247] Among them, G mb is the hot air flow rate after supercharging, kg / s; G mw is the cooling air medium flow rate, kg / s; C pb is the specific calorific value of the hot air after supercharging, J / kg·℃; C pw is the specific heat of cooling air medium, J / kg·℃; T b1 is the hot air temperature at the intercooler inlet; T b2 is the intercooler outlet (cooled air) temperature; T w1 is the temperature of the cooling air medium entering the intercooler; T w2 The temperature of the cooling air medium leaving the intercooler (℃).

[0248] Substituting the above parameters into formula (43), we can get the parameter T w2 .

[0249] 2) Calculation of average temperature difference:

[0250] ① Average temperature on the cold side:

[0251] t wm =(T w1 +T w2 ) / 2 (44)

[0252] ②Average temperature on hot side:

[0253] t bm =(T b1 +T b2 ) / 2 (45)

[0254] ③ Average convection temperature difference on the hot side Δt m :

[0255] Δt m =[(T b1 -T w2 )-(T b2 -T w1 )]ψln[(T b1 -T w2 ) / (T b2 -T w1 )] (46)

[0256] Where ψ is the correction parameter.

[0257] 3) Calculation of intercooler heat exchange capacity and cooling efficiency

[0258] ①Intercooler heat exchange capacity:

[0259] Q X =q mb C pb ΔT=q mb C pb (T b -T s ) (47)

[0260] ②Cooling efficiency:

[0261]

[0262] 4) Calculation of thermophysical parameters of cold and hot side air at average temperature

[0263] ① Density

[0264] Cold side air density:

[0265]

[0266] Hot side air density:

[0267]

[0268] Where: p b is the pressure after supercharging; Δp b is the pressure loss of the intercooler system, which is 3kPa; R is the gas constant, R=287; T bm is the average temperature of the hot side air.

[0269] ②Kinematic viscosity

[0270]

[0271] ③ Thermal conductivity

[0272]

[0273] ④ Prandtl number

[0274]

[0275] ⑤Calculate the convection heat transfer coefficient

[0276] a) Cold side convection heat transfer coefficient

[0277] Cold side air velocity:

[0278]

[0279] Cold side air Reynolds number

[0280] R ew =C w D ew / υ w (55)

[0281] Nusselt number for cold-side air

[0282]

[0283] Cold side air convection heat transfer coefficient

[0284] h w =N uw λ w / D ew (57)

[0285] b) Hot side convective heat transfer coefficient

[0286] Charge air flow rate:

[0287]

[0288] Hot side air Reynolds number

[0289] R eb =C b D eb / υ b (59)

[0290] Nusselt number of hot side air

[0291]

[0292] Hot side air convection heat transfer coefficient

[0293] h b =N ub λ b / D eb (61)

[0294] ⑥ Calculation of thermal resistance

[0295] Hot side dirt thermal resistance R1 = 0.00035m 2 K / W;

[0296] Cold side dirt thermal resistance R2 = 0.00035m 2 K / W;

[0297] Contact thermal resistance of heat sink welding point R3=0.0001m 2 K / W;

[0298] Thermal resistance of heat sink material:

[0299] R4=A b ·δ2 / (A w ·λ)=2.85×10 -6 m 2 ·K / W (62)

[0300] Where: λ is the thermal conductivity of the material, which is 140 W / m·K.

[0301] ⑦Heat transfer coefficient of intercooler

[0302]

[0303] Where: h b h is the convection heat transfer coefficient between the high temperature air in the intercooler and the intercooler wall; w is the convective heat transfer coefficient between the atmospheric air outside the intercooler and the intercooler wall.

[0304] Substituting the above parameters into formula (70), we get: K = 23.27W / (m 2 ·K).

[0305] (1) Intercooler geometric parameter design calculation formula:

[0306] 1) Calculation of equivalent diameter De

[0307] ①Cold side:

[0308]

[0309] Where: x W and y W They are the inner distance and inner height of the cold side fin of the radiator respectively.

[0310] ②Hot side:

[0311]

[0312] Where: x b and y b They are the inner distance and inner height of the radiator thermal side fins respectively.

[0313] 2) Calculation of flow cross-sectional area F

[0314] ①Cold side flow cross-sectional area F w

[0315]

[0316] Among them, B w is the effective width of the cold side, S w is the cold side fin spacing, and n is the number of cooling tubes.

[0317] ②Hot side flow cross-sectional area F b

[0318]

[0319] Among them, S b is the hot side fin spacing, B b is the effective width of the hot side, and n is the number of cooling tubes.

[0320] (3) Intercooler heat dissipation area verification formula:

[0321] 1) Calculation of actual heat dissipation area

[0322] ①Cold side heat dissipation area A w

[0323]

[0324] Among them, L w is the effective length of the cold side, x W is the inner distance of the cold side wing, and yW is the inner height of the cold side wing.

[0325] ②Hot side heat dissipation area A b

[0326]

[0327] Among them, L b is the effective length of the hot side, x b is the inner distance of the hot side wing, y b The inner side wings are high for heat.

[0328] ③Total heat dissipation area A:

[0329] A=A w +A b (70)

[0330] 2) Minimum heat dissipation area A required for charge air cooling C :

[0331]

[0332] If the actual heat dissipation area A of the intercooler is greater than A C , the intercooler heat dissipation area calibration is qualified, and the designed intercooler meets the cooling index requirements; otherwise, the above intercooler design parameters need to be modified to meet the cooling requirements.

[0333] Step 8: Complete the research on the control strategy of parameters such as the second-stage supercharger's pressurized air inlet flow rate and its turbine bypass valve bleed rate;

[0334] Step 9: Complete the development of the software and hardware control system for parameters such as the second-stage supercharger's pressurized air inlet flow rate and turbine bleed rate.

[0335] Since then, the difficult problem of energy-saving and environmentally friendly vehicle cabin air pressurization based on the kinetic energy of vehicle engine exhaust gas turbocharging has been completed / realized.

[0336] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A design method for a vehicle cabin air boosting device based on the kinetic energy of an engine exhaust turbine, characterized in that: The device comprises: a second-stage supercharger turbine, a second-stage supercharger turbine end regulating valve, a second-stage supercharger intercooler, a supercharger cabin regulating valve, a second-stage supercharger compressor regulating valve, a supercharger cabin and a second-stage supercharger compressor; The second-stage supercharger turbine is used to connect to the exhaust port of the first supercharger turbine of the engine, the second-stage supercharger turbine end regulating valve is connected in parallel to both ends of the second-stage supercharger turbine, the turbine shaft of the second-stage supercharger turbine is connected to the second-stage supercharger compressor, the second-stage supercharger compressor regulating valve is connected in parallel to both ends of the second-stage supercharger compressor, the high-pressure air output pipeline of the second-stage supercharger compressor is connected to the supercharger cabin, and the supercharger cabin regulating valve and the second-stage supercharger intercooler are arranged on the high-pressure air output pipeline; The design method of the device includes the following specific steps: Step 1: Establish a supercharged engine thermodynamic simulation model; Step 2: Calculate the intake mass flow rate and exhaust mass flow rate of the internal combustion engine at different altitudes based on the input altitude parameters and engine parameters; Step 3: Calculate the second-stage supercharger turbine intake volume and the air bleed rate of the second-stage supercharger turbine end regulating valve at different altitudes based on the input supercharger cabin pressure, supercharger cabin air flow rate, and supercharger cabin air density; Step 4: Calculate the parameters of the second-stage turbocharger turbine and the second-stage turbocharger compressor; Step 5: Calculate the MAP characteristic curve of the second-stage supercharger at different altitudes; Step 6: Calculate the heat dissipation of the pressurized air of the second-stage supercharger compressor at different altitudes by comparing the inputted pressurized cabin air temperature adjustment index parameter; Step 7: Calculate the parameters of the intercooler of the second-stage turbocharger; Step 8: Complete the research on the control strategy of the second-stage supercharger's pressurized air inlet flow rate and its turbine bypass valve bleed rate; Step 9: Complete the development of the software and hardware control system for the second-stage supercharger's pressurized air inlet flow rate and its turbine bypass valve air bleed rate.

2. The design method of the vehicle cabin air boosting device based on the engine exhaust turbine kinetic energy according to claim 1 is characterized in that: The parameters of the second stage turbocharger compressor include: Impeller inlet area F1 design: Where ρ1 is the air density at the impeller inlet, c 1a is the axial velocity of the airflow at the impeller inlet, G c is the engine intake air mass flow rate; Impeller inlet outer diameter D1: Where: D0 is the outer diameter of the impeller hub at the inlet; Impeller outlet diameter D2: Impeller outlet width b2: Among them, τ2 is the blockage coefficient at the impeller outlet, ρ2 is the air density at the impeller outlet, c 2r is the radial component of the absolute velocity at the outer edge of the impeller diameter; Compressor volute outlet area A y : Where ρ5 is the gas density at the compressor volute outlet, c y is the air velocity at the compressor volute outlet.

3. The design method of the vehicle cabin air boosting device based on the engine exhaust turbine kinetic energy according to claim 1 is characterized in that: The parameters of the second stage turbocharger turbine include: in, is the turbine mass flow rate; p4 is the exhaust pressure after the turbine; p3 is the exhaust pressure before the turbine; κ3 is the turbine constant entropy index, μ T is the turbine circumferential speed, and ρ3 is the exhaust gas density before the turbine.

4. The design method of the vehicle cabin air boosting device based on the engine exhaust gas turbine kinetic energy according to claim 1, 2 or 3, characterized in that: The parameters of the intercooler are: 1) Equivalent diameter De is: ①Cold side: Where: x W and y W They are the inner distance and inner height of the fin on the cold side of the radiator respectively; ②Hot side: Where: x b and y b are the inner distance and inner height of the radiator hot side fin respectively; 2) The flow cross-sectional area F is: ①Cold side flow cross-sectional area F w Among them, B w is the effective width of the cold side, S w is the cold side fin spacing, n is the number of cooling tubes; ②Hot side flow cross-sectional area F b Among them, S b is the hot side fin spacing, B b is the effective width of the hot side; (3) Intercooler cooling area is: 1) Calculation of actual heat dissipation area ①Cold side heat dissipation area A w Among them, L w is the effective length of the cold side, x W is the inner distance of the cold side wing, y W The inner side of the cold side wing is high; ②Hot side heat dissipation area A b Among them, L b is the effective length of the hot side, x b is the inner distance of the cold side wing, y b The inner side of the cold side wing is high; ③Total heat dissipation area A: A=A w +A b 2) Minimum heat dissipation area A required for charge air cooling C for: Among them, G mb is the hot air flow after supercharging, K is the heat transfer coefficient of the intercooler, ΔT n is the difference between the inlet and outlet temperatures of the intercooler; And the actual heat dissipation area A of the intercooler is greater than A C .

5. The design method of the vehicle cabin air boosting device based on the engine exhaust turbine kinetic energy according to claim 4 is characterized in that: When the total heat dissipation area A of the intercooler is less than the minimum heat dissipation area A required for the charge air cooling C When the intercooler is turned off, adjust the design parameters of the intercooler until its total heat dissipation area A is greater than or equal to A C .

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