A turbocharger hardware protection method based on dynamic density limitation

Abstract

The present invention discloses a supercharger hardware protection method based on dynamic density limitation, comprising: determining the pressure ratio of the supercharger according to the flow density entering the engine, engine speed, pressure after intercooling, temperature after intercooling, and pressure after air filter; determining the supercharger outlet temperature according to the temperature after air filter and the pressure ratio; determining the charging efficiency limit value according to the engine speed, flow density entering the engine, and charging efficiency; determining the pressure-limited air volume according to the engine speed and the charging efficiency limit value; determining the speed-limited air volume according to the charging efficiency limit value, the temperature of the engine intake manifold, engine speed, temperature after air filter, atmospheric pressure, temperature after intercooling, and supercharger outlet temperature; and determining the final air volume limit density according to the pressure-limited air volume and the speed-limited air volume. This method achieves effective protection for the supercharger.

Description

Technical Field

[0001] The present invention relates to the field of engine control, and in particular to a supercharger hardware protection method based on dynamic density limitation. Background Art

[0002] A supercharger uses high-temperature exhaust gas from the engine to drive the turbine in the turbine. The turbine shaft then spins the impeller in the compressor at high speed, centrifugally compressing the air and increasing the density of the engine's intake air. This increases the engine's power. It is widely used in the automotive industry, with the vast majority of engines employing turbocharging. Due to the high-temperature, high-pressure, and high-speed operating environment, superchargers have significant durability limits, such as maximum compression ratio and speed. When these limits are exceeded, the supercharger is extremely susceptible to failure and damage. To ensure operational reliability, it is necessary to ensure that the supercharger operates within these limits.

[0003] Chinese patent CN109931171A provides a supercharger protection method. This solution obtains data such as intercooler pressure difference, intercooler pressure after intercooler, supercharger intake temperature, intake pressure, and equivalent intake mass flow rate. Based on this data, it calculates the intercooler pressure before and supercharger pressure ratio. The supercharger efficiency, supercharger intake temperature, and supercharger pressure ratio are then substituted into the supercharger isentropic efficiency calculation formula to finally obtain the compressor outlet temperature. This method only considers supercharger overtemperature protection, not excessive supercharger pressure ratio or overspeed protection, and is not suitable for superchargers with bypass devices.

[0004] Chinese patent CN105649759A provides a turbocharger protection system. This solution adds a boost pressure sensor to obtain real-time boost pressure, calibrates the torque limit based on engine speed and atmospheric pressure, and then calibrates the torque limit based on engine speed, intake air temperature, and engine boost pressure, obtaining the minimum of the three to obtain the final torque limit. The system's drawbacks include the need for a boost pressure sensor, the fact that all limits are obtained on a test bench, and the imprecise table-based values. The limits are too crude, making it impossible to accurately and real-timely obtain supercharger parameters, impose limits without fully utilizing supercharger performance, and are not suitable for superchargers with bypass devices. Summary of the Invention

[0005] The object of the present invention is to provide a supercharger hardware protection method based on dynamic density limitation to achieve protection of the supercharger.

[0006] To solve the above technical problems, the present invention provides a method for protecting turbocharger hardware based on dynamic density limitation, comprising:

[0007] The pressure ratio of the supercharger is determined based on the flow density entering the engine, engine speed, pressure after the intercooler, temperature after the intercooler, and pressure after the air filter; wherein the flow density entering the engine, engine speed, pressure after the intercooler, temperature after the intercooler, and pressure after the air filter are all obtained through testing;

[0008] Determine the turbocharger outlet temperature based on the post-air filter temperature and pressure ratio; the post-air filter temperature is obtained through testing;

[0009] Determine the charging efficiency limit value according to the engine speed, the flow density entering the engine, and the charging efficiency; wherein the charging efficiency is obtained through testing;

[0010] Determine the pressure limit gas volume based on the engine speed and charging efficiency limit value;

[0011] The speed-limited air volume is determined based on the charging efficiency limit value, the temperature of the engine intake manifold, the engine speed, the temperature after the air filter, the atmospheric pressure, the temperature after the intercooler, and the supercharger outlet temperature; wherein the temperature of the engine intake manifold and the atmospheric pressure are obtained through testing;

[0012] The final air volume limiting density is determined according to the pressure limiting air volume and the speed limiting air volume; the final air volume limiting density is used to limit the intake density of the supercharger.

[0013] According to the above scheme, the method for determining the pressure ratio of the supercharger based on the flow density entering the engine, the engine speed, the pressure after the intercooler, the temperature after the intercooler, and the pressure after the air filter includes:

[0014] Determine the intake air flow rate into the cylinder based on the flow density entering the engine, the displacement of a single cylinder, the number of engine cylinders, and the engine speed;

[0015] Determine the first bypass flow rate based on the pressure after the intercooler, the temperature after the intercooler, and the pressure after the air filter;

[0016] Determine the supercharger flow rate according to the first bypass flow rate and the intake air flow rate entering the cylinder;

[0017] Determine the supercharger outlet pressure based on the pressure after intercooling, the intake air flow into the cylinder, and the supercharger flow;

[0018] Determine the supercharger inlet pressure based on the pressure after the air filter;

[0019] Determine the pressure ratio based on the supercharger inlet pressure and supercharger outlet pressure.

[0020] According to the above scheme, the method for determining the supercharger outlet temperature based on the air filter temperature and pressure ratio includes:

[0021] Determine the supercharger speed correction coefficient based on the temperature after the air filter;

[0022] Determine the supercharger flow correction coefficient based on the supercharger speed correction coefficient and the temperature after the air filter;

[0023] Determine the supercharger flow correction value according to the supercharger flow correction coefficient and the supercharger flow;

[0024] Determine the efficiency of the supercharger based on the supercharger flow correction value and pressure ratio;

[0025] Determine the supercharger outlet temperature based on the air filter temperature, pressure ratio, and supercharger efficiency.

[0026] According to the above solution, the method for determining the charging efficiency limit value based on the engine speed, the flow density entering the engine, and the charging efficiency includes:

[0027] Determine the maximum charging efficiency based on the engine speed;

[0028] Determine the engine gas volume deviation based on the flow density entering the engine;

[0029] Determine the maximum charging efficiency weight according to the engine gas volume deviation and engine speed;

[0030] The inflation efficiency limit value is determined based on the inflation efficiency and the weight of the maximum inflation efficiency ratio.

[0031] According to the above solution, the method for determining the pressure-limited gas volume based on the engine speed and the charging efficiency limit value includes:

[0032] Determine the maximum boost pressure limit value according to the engine speed;

[0033] The pressure-limited air volume is determined according to the maximum boost pressure limit value, the charging efficiency limit value, and the temperature of the engine intake manifold; wherein the temperature of the engine intake manifold is obtained through detection.

[0034] According to the above scheme, the method for determining the speed-limited air volume based on the charging efficiency limit value, the temperature of the engine intake manifold, the engine speed, the temperature after the air filter, the atmospheric pressure, the temperature after the intercooler, and the supercharger outlet temperature includes:

[0035] Determining a pressure limit value at the intake manifold based on a charging efficiency limit value, a temperature of the engine intake manifold, and a weight of a maximum charging efficiency ratio; wherein the temperature of the engine intake manifold is obtained by detection;

[0036] determining an engine intake air flow limit value according to the engine speed;

[0037] Determine the air filter pressure drop based on the engine intake flow limit, air filter temperature, and atmospheric pressure;

[0038] Determine the supercharger inlet pressure limit based on the air filter pressure drop;

[0039] The second bypass flow is determined based on the intake manifold pressure limit, the supercharger inlet pressure limit, and the intercooler temperature.

[0040] determining a supercharger flow limit value according to a second bypass flow rate and an engine intake flow limit value;

[0041] Determine the supercharger outlet pressure limit value based on the intake manifold pressure limit value, engine intake flow limit value, and supercharger outlet temperature;

[0042] Determine the predicted maximum limiting pressure ratio based on atmospheric pressure and supercharger flow correction value;

[0043] Determine the supercharger outlet pressure deviation based on the supercharger outlet pressure and supercharger inlet pressure limits;

[0044] Determine the outlet pressure based on the outlet pressure deviation of the supercharger;

[0045] Determine the predicted limiting pressure ratio based on the outlet pressure and supercharger inlet pressure limit;

[0046] Determine the predicted pressure ratio deviation according to the predicted maximum limit pressure ratio and the predicted limit pressure ratio;

[0047] Determine the density increment step size based on the predicted pressure ratio deviation;

[0048] The speed limiting gas volume is determined based on the density increment step.

[0049] According to the above scheme, the method for determining the final gas volume limit density based on the pressure limit gas volume and the speed limit gas volume is:

[0050] The final air volume limit density is set to the smaller value of the speed limit air volume and the pressure limit air volume.

[0051] The present invention also provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the booster hardware protection method based on dynamic density limitation described above are implemented.

[0052] The present invention also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the computer program implements the steps of the above-mentioned method for protecting booster hardware based on dynamic density limitation.

[0053] The present invention also provides a vehicle, which executes the steps of the above-mentioned method for protecting supercharger hardware based on dynamic density limitation.

[0054] The present invention has the following beneficial effects: a supercharger-related physical model is established based on supercharger gas characteristics, and supercharger-related parameters are modified to obtain characteristic parameters under standard environmental conditions. Based on the intake air density limit at the previous moment, an iterative method is used to calculate the limited air volume according to the maximum pressure limit and the speed limit, respectively. This limits the supercharger air volume, indirectly limiting the maximum pressure and supercharger speed, thereby achieving the purpose of protecting the supercharger hardware. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a flow chart of a method for protecting booster hardware based on dynamic density limitation;

[0056] Figure 2 This is a schematic diagram of the engine intake and exhaust configuration and sensor arrangement applicable to the turbocharger hardware protection method based on dynamic density limitation;

[0057] Figure 3 is a schematic diagram of performing a linear difference lookup on a pre-calibrated first table;

[0058] Figure 4 is a schematic diagram of performing a linear difference lookup on a pre-calibrated second table;

[0059] Figure 5 It is a schematic diagram of performing a linear difference lookup on a pre-calibrated third table;

[0060] Figure 6 is a schematic diagram of performing a linear difference lookup on a pre-calibrated fourth table;

[0061] Figure 7 This is a data flow diagram of a booster hardware protection method based on dynamic density limitation. DETAILED DESCRIPTION

[0062] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0063] Example 1:

[0064] See also Figure 1 、 Figure 2 、 Figure 7 This embodiment discloses a method for protecting booster hardware based on dynamic density limitation, comprising the following steps:

[0065] S1. Determine a supercharger pressure ratio R_CompPressureRatio based on measured flow density RHO_CylAirDensity entering the engine, engine speed N_EngSpd, intercooler pressure P_PreThrottle, intercooler temperature TK_PreThrottle, and air filter pressure P_AirFilter.

[0066] S1 specifically includes the following steps:

[0067] S101, determining the intake air flow rate DM_CylinderAirFlow entering the cylinder based on the flow density RHO_CylAirDensity entering the engine, the single-cylinder displacement V_CylinderDisplacement, the number of engine cylinders Ncyl, and the engine speed N_EngSpd;

[0068] DM_CylinderAirFlow=RHO_CylAirDensity*V_CylinderDisplacement*Ncyl*N_EngSpd*1000

[0069] The flow density RHO_CylAirDensity entering the engine is obtained by other modules of the ECU controller according to the conventional speed density method. The single-cylinder displacement V_CylinderDisplacement and the number of engine cylinders Ncyl are determined according to the engine characteristics. The engine speed N_EngSpd is obtained through the corresponding sensor.

[0070] S102, determining a first bypass flow rate DM_venturi according to the post-intercooler pressure P_PreThrottle, the post-intercooler temperature TK_PreThrottle, and the post-air filter pressure P_AirFilter;

[0071]

[0072] In the above formula, K_Rair is the gas constant, which is 287 in this embodiment; Cv is the gas heat capacity, which is 0.9 in this embodiment; A_VenturiAreaCorrelation is the pipe diameter area of ​​the bypass device; the intercooler pressure P_PreThrottle, the intercooler temperature TK_PreThrottle, and the air filter pressure P_AirFilter are obtained by detecting corresponding sensors.

[0073] The bypass device is provided on the supercharger. In this embodiment, the bypass device is a venturi tube. The above formula is obtained based on the fluid characteristics of the venturi tube.

[0074] S103, determining the supercharger flow rate DM_CompressorFlow according to the first bypass flow rate DM_venturi and the intake air flow rate into the cylinder DM_CylinderAirFlow;

[0075] DM_CompressorFlow=DM_CylinderAirFlow+DM_venturi

[0076] S104 , determining the supercharger outlet pressure P_CompressorOut (i.e., the pressure before the intercooler) based on the post-intercooler pressure P_PreThrottle, the intake air flow rate into the cylinder DM_CylinderAirFlow, and the supercharger flow rate DM_CompressorFlow;

[0077] P_CompressorOut=P_PreThrottle / 2+sqrt(P_PreThrottle^2 / 4+DM_CompressorF low^2*cal*TK_ComprOutlet(z))

[0078] In the above formula, cal is the intercooler pressure drop characteristic coefficient, which is determined by the intercooler characteristics; TK_ComprOutlet(z) is the value of the supercharger outlet temperature TK_ComprOutlet in the previous calculation cycle;

[0079] S105. Determine the supercharger inlet pressure P_CompressorInlet according to the air filter pressure P_AirFilter;

[0080] Since the supercharger inlet pipe and the air filter outlet pipe are short, it is assumed that the supercharger inlet pressure P_CompressorInlet is equal to the air filter outlet pressure P_AirFilter;

[0081] S106 , determining a pressure ratio R_CompPressureRatio based on the supercharger inlet pressure P_CompressorInlet and the supercharger outlet pressure P_CompressorOut;

[0082] R_CompPressureRatio=P_CompressorOut / P_CompressorInlet

[0083] S2. Determine the supercharger outlet temperature TK_ComprOutlet based on the air filter temperature TK_AirFilter and the pressure ratio R_CompPressureRatio;

[0084] S2 specifically includes the following steps:

[0085] S201. Determine a supercharger speed correction factor R_CompSpdCorrFactorNcor based on the detected air filter temperature TK_AirFilter.

[0086]

[0087] The air filter temperature TK_AirFilter is obtained through the corresponding sensor. TK_StdCompFlowTempInv is the set temperature standard deviation correction coefficient, which is 0.003 in this example.

[0088] S202, determining a supercharger flow correction factor R_CompMassFlowCorrFactor based on the supercharger speed correction factor R_CompSpdCorrFactorNcor and the air filter post-temperature TK_AirFilter;

[0089] R_CompMassFlowCorrFactor

[0090] =R_CompSpdCorrFactorNcor / ((TK_AirFilter+273K)

[0091] *P_StdCompFlowPressInv)

[0092] In the above formula, P_StdCompFlowPressInv is the set pressure standard deviation correction coefficient, which is 0.01 in this example;

[0093] S203, determining a supercharger flow correction value Dm_CompressorFlowCorr according to the supercharger flow correction coefficient R_CompMassFlowCorrFactor and the supercharger flow DM_CompressorFlow;

[0094] Dm_CompressorFlowCorr

[0095] =Dm_CompressorFlow*R_CompMassFlowCorrFactor

[0096] S204, determining the supercharger efficiency R_CompEfficiency according to the supercharger flow correction value Dm_CompressorFlowCorr and the pressure ratio R_CompPressureRatio;

[0097] According to the turbocharger flow correction value Dm_CompressorFlowCorr and the pressure ratio R_CompPressureRatio, a linear interpolation lookup table is performed on the pre-calibrated first table (see Figure 3 ), obtain the supercharger efficiency R_CompEfficiency;

[0098] S205 , determining the supercharger outlet temperature TK_ComprOutlet based on the air filter temperature TK_AirFilter, the pressure ratio R_CompPressureRatio, and the supercharger efficiency R_CompEfficiency;

[0099] TK_ComprOutlet

[0100] =TK_AirFilter*(1+(R_CompPressureRatio^((gamma_a

[0101] -1) / gamma_a)-1) / R_CompEfficiency)

[0102] In the above formula, gamma_a is the set specific heat of air, which is 1.4 in this embodiment.

[0103] S3. Determine a charging efficiency limit value R_VolumetricEfficiency based on the engine speed N_EngSpd, the flow density RHO_CylAirDensity entering the engine, and the charging efficiency R_VolumetricEfficiencyCurr.

[0104] The charging efficiency R_VolumetricEfficiencyCurr is obtained through detection. It should be understood that since the charging efficiency is calculated in real time based on the parameters obtained under the current working conditions, rather than calculated under the theoretical maximum value, there will be errors when used for predictive calculations. In order to improve this situation, it is necessary to obtain the maximum allowable charging efficiency at a certain engine speed in advance and weight it with the actual charging efficiency.

[0105] S3 specifically includes the following steps:

[0106] S301. Determine the maximum charging efficiency R_VolumetricEfficiencyMax based on the engine speed N_EngSpd.

[0107] According to the engine speed N_EngSpd, a linear difference lookup table is performed on the pre-calibrated second table (see Figure 4 ), get the maximum inflation efficiency R_VolumetricEfficiencyMax;

[0108] S302, determining the engine air volume deviation RHO_error according to the flow density RHO_CylAirDensity entering the engine;

[0109] RHO_error=RHO_TurboLimMax(z)-RHO_CylAirDensity

[0110] In the above formula, RHO_TurboLimMax(z) is the value of the turbocharger's maximum air volume limit RHO_TurboLimMax in the previous operation cycle;

[0111] S303 , determining a maximum charging efficiency weight VE_Weight based on the engine air volume deviation RHO_error and the engine speed N_EngSpd;

[0112] According to the engine gas volume deviation RHO_error and the engine speed N_EngSpd, a linear interpolation lookup table is performed on the pre-calibrated third table (see Figure 5 ), obtain the maximum inflation efficiency weight VE_Weight;

[0113] S304 , determining a charging efficiency limit value R_VolumetricEfficiency according to the charging efficiency R_VolumetricEfficiencyCurr and the maximum charging efficiency weight VE_Weight;

[0114] R_VolumetricEfficiency

[0115] =VE_Weight*R_VolumetricEfficiencyCurr+(1-VE_Weight)

[0116] *R_VolumetricEfficiencyCurr

[0117] S4. Determine the pressure limit volume RHO_BL_MaxPressLim based on the engine speed N_EngSpd and the charging efficiency limit value R_VolumetricEfficiency.

[0118] S4 specifically includes the following steps:

[0119] S401. Determine a maximum boost pressure limit value p(N) based on the engine speed N_EngSpd.

[0120] According to the engine speed N_EngSpd, a pre-calibrated third table is linearly interpolated to obtain the maximum boost pressure limit value p(N);

[0121] S402 , determining a pressure limit volume RHO_BL_MaxPressLim based on a maximum boost pressure limit value p(N), a charging efficiency limit value R_VolumetricEfficiency, and a temperature TK_PortTemp of the engine intake manifold;

[0122]

[0123] In the above formula, R is the air constant, which is 288;

[0124] TK_PortTemp is the engine intake manifold temperature obtained through detection.

[0125] S5. Determine the speed limit air volume RHO_OvrspdSrgMax based on the charging efficiency limit value R_VolumetricEfficiency, the engine intake manifold temperature TK_PortTemp, the engine speed N_EngSpd, the air filter post-temperature TK_AirFilter, the atmospheric pressure P_Ambient, the intercooler post-temperature TK_PreThrottle, and the supercharger outlet temperature TK_ComprOutlet.

[0126] S5 specifically includes the following steps:

[0127] S501 , determining a pressure limit value P_MAPAtMaxEst at the intake manifold based on a charging efficiency limit value R_VolumetricEfficiency, a temperature TK_PortTemp of the engine intake manifold, and a maximum charging efficiency weight VE_Weight;

[0128] P_MAPAtMaxEst

[0129] =RHO_OvrspdSrgMax(z)*R_VolumetricEfficiency

[0130] *TK_PortTemp / VE_Weight

[0131] In the above formula, RHO_OvrspdSrgMax(z) is the value of the speed limit air volume RHO_OvrspdSrgMax in the previous operation cycle;

[0132] S502 , determining an engine intake air flow limit value DM_CylFlowAtMaEst according to the engine speed N_EngSpd;

[0133] DM_CylFlowAtMaEst=RHO_OvrspdSrgMax(z)*V_CylinderDisplacement*Ncyl*N_EngSpd / 120 / 1000

[0134] In the above formula, V_CylinderDisplacement is the engine displacement set based on engine characteristics;

[0135] S503 , determining the air filter pressure drop P_AirFilterPressDrop based on the engine intake air flow limit value DM_CylFlowAtMaEst, the air filter post-temperature TK_AirFilter, and the atmospheric pressure P_Ambient;

[0136] P_AirFilterPressDrop=DM_CylFlowAtMaEst^2*(TK_AirFilter+273K) / P_Ambient*K_AirFilt

[0137] The atmospheric pressure P_Ambient is obtained through the corresponding sensor detection; K_AirFilt is the air filter coefficient set according to the air filter characteristics;

[0138] S504. Determine the supercharger inlet pressure limit P_CompInAtMaxEst based on the air filter pressure drop P_AirFilterPressDrop;

[0139] P_CompInAtMaxEst=P_Ambient-P_AirFilterPressDrop

[0140] S505 , determining a second bypass flow rate DM_venturi_est_lim based on the intake manifold pressure limit value P_MAPAtMaxEst, the supercharger inlet pressure limit value P_CompInAtMaxEst, and the intercooler post-temperature TK_PreThrottle;

[0141]

[0142] S506 , determining a supercharger flow limit DM_CompressorFlow_Lim according to the second bypass flow DM_venturi_est_lim and the engine intake flow limit DM_CylFlowAtMaEst;

[0143] DM_CompressorFlow_Lim=DM_CylFlowAtMaxEst+DM_venturi_est_lim

[0144] S507 , determining a supercharger outlet pressure limit value P_CompOutAtMaxEst based on the intake manifold pressure limit value P_MAPAtMaxEst, the engine intake air flow limit value DM_CylFlowAtMaEst, and the supercharger outlet temperature TK_ComprOutlet;

[0145] P_CompOutAtMaxEst

[0146] =P_MAPAtMaxEst / 2+sqrt(P_MAPAtMaxEst^2 / 4+K

[0147] *DM_CylFlowAtMaxEst^2*TK_ComprOutlet)

[0148] It can be understood that the bypass valve inlet pressure is the pressure after the intercooler, and the throttle is fully open at this time, so the pressure limit value P_MAPAtMaxEst at the intake manifold is equal to the manifold pressure;

[0149] S508 , determining a predicted maximum limit pressure ratio R_CompRatioMaxAtMaxEst based on the atmospheric pressure P_Ambient and the supercharger flow correction value Dm_CompressorFlowCorr;

[0150] According to the atmospheric pressure P_Ambient and the turbocharger flow correction value Dm_CompressorFlowCorr, a linear interpolation lookup table is performed on the pre-calibrated fourth table (see Figure 6 ), obtain the predicted maximum limit pressure ratio R_CompRatioMaxAtMaxEst;

[0151] S509 , determining a supercharger outlet pressure deviation P_error according to the supercharger outlet pressure P_CompressorOut and the supercharger inlet pressure limit P_CompInAtMaxEst;

[0152] P_error=P_CompressorOut-P_CompInAtMaxEst

[0153] S510, determining the outlet pressure P_Out according to the supercharger outlet pressure deviation P_error;

[0154] When the pressure deviation P_error of the supercharger outlet is greater than the set value (10 kPa in this embodiment), the outlet pressure P_Out is set equal to P_CompressorOut; otherwise, the outlet pressure P_Out is set equal to the supercharger inlet pressure limit P_CompInAtMaxEst.

[0155] S511, determining a predicted limit pressure ratio R_est according to the outlet pressure P_Out and the supercharger inlet pressure limit P_CompInAtMaxEst;

[0156] R_est=P_Out / P_CompInAtMaxEst

[0157] S512 , determining a predicted pressure ratio deviation P_errorEst based on the predicted maximum limit pressure ratio R_CompRatioMaxAtMaxEst and the predicted limit pressure ratio R_est;

[0158] P_errorEst=R_CompRatioMaxAtMaxEst-R_est

[0159] S513, determining the density increment step length RHO_BL_Step according to the predicted pressure ratio deviation P_errorEst;

[0160] RHO_BL_Step=K_OvrspGain*P_errorEst

[0161] In the above formula, K_OvrspGain is the set density change rate coefficient, which is set to 50 in this embodiment;

[0162] S514. Determine the speed limit gas volume RHO_OvrspdSrgMax according to the density increment step RHO_BL_Step;

[0163] RHO_OvrspdSrgMax=RHO_OvrspdSrgMax(z)+RHO_BL_Step

[0164] In the above formula, RHO_OvrspdSrgMax(z) is the value of the speed-limited air volume RHO_OvrspdSrgMax in the previous calculation cycle. It can be understood that when the estimated pressure is greater than the maximum allowable pressure and the density increment step is less than 0, RHO_BL_Step is negative, and RHO_OvrspdSrgMax decreases. When the estimated pressure is greater than the maximum allowable pressure and the density increment step is greater than 0, RHO_BL_Step is positive, and RHO_OvrspdSrgMax increases.

[0165] S6. Determine the final air volume limit density RHO_TurboLimMax based on the speed limit air volume RHO_OvrspdSrgMax and the pressure limit air volume RHO_BL_MaxPressLim;

[0166] The final air volume limit density RHO_TurboLimMax is set to the smaller value of the speed limit air volume RHO_OvrspdSrgMax and the pressure limit air volume RHO_BL_MaxPressLim; the final air volume limit density RHO_TurboLimMax is used to limit the intake density of the turbocharger.

[0167] Example 2:

[0168] This embodiment discloses a computer device for implementing the method described in Example 1. The computer device can be a smart phone, tablet computer, laptop computer, desktop computer, rack server, blade server, tower server or cabinet server (including an independent server, or a server cluster composed of multiple servers) that can execute a program. The computer device of this embodiment includes at least but is not limited to: a memory and a processor that can be interconnected through a system bus. It should be noted that only a computer device with components is shown, but it should be understood that it is not required to implement all the components shown, and more or fewer components can be implemented instead.

[0169] In this embodiment, the memory (i.e., readable storage medium) includes flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and programmable read-only memory (PROM). The memory may also be an external storage device of the computer device, such as a plug-in hard disk equipped with the computer device, a smart memory card (SMC), a secure digital (SD) card, a flash memory card, etc. Of course, the memory may also include both the internal storage unit of the computer device and its external storage device. In this embodiment, the memory is generally used to store the operating system and various application software installed in the computer device, such as the program code of the booster hardware protection method based on dynamic density limitation in Example 1. In addition, the memory can also be used to temporarily store various types of data that have been output or are about to be output.

[0170] In some embodiments, the processor may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chip. The processor is typically used to control the overall operation of a computer device. In this embodiment, the processor is used to execute program code stored in a memory or process data, such as executing a booster hardware protection method based on dynamic density limitation.

[0171] Example 3:

[0172] This embodiment provides a computer-readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card-type memory (e.g., SD or DX memory), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a disk, an optical disk, a server, an App store, etc., storing a computer program that implements corresponding functions when executed by a processor. The computer-readable storage medium of this embodiment is used to store program code for a method for protecting booster hardware based on dynamic density limitation, and when executed by a processor, implements the method for protecting booster hardware based on dynamic density limitation of Example 1.

[0173] Example 4:

[0174] This embodiment provides a car that implements the supercharger hardware protection method based on dynamic density limitation described in the first embodiment.

[0175] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0176] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, or two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0177] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for protecting turbocharger hardware based on dynamic density limitation, characterized in that: include: The pressure ratio of the supercharger is determined based on the flow density entering the engine, engine speed, pressure after the intercooler, temperature after the intercooler, and pressure after the air filter; wherein the flow density entering the engine, engine speed, pressure after the intercooler, temperature after the intercooler, and pressure after the air filter are all obtained through testing; Determine the turbocharger outlet temperature based on the post-air filter temperature and pressure ratio; the post-air filter temperature is obtained through testing; Determine the charging efficiency limit value based on the engine speed, the flow density entering the engine, and the charging efficiency; The inflation efficiency is obtained through testing; Determine the pressure limit gas volume based on the engine speed and charging efficiency limit value; The speed-limited air volume is determined based on the charging efficiency limit value, the temperature of the engine intake manifold, the engine speed, the temperature after the air filter, the atmospheric pressure, the temperature after the intercooler, and the supercharger outlet temperature; wherein the temperature of the engine intake manifold and the atmospheric pressure are obtained through testing; The final air volume limiting density is determined according to the pressure limiting air volume and the speed limiting air volume; the final air volume limiting density is used to limit the intake density of the supercharger.

2. The method for protecting turbocharger hardware based on dynamic density limitation according to claim 1, characterized in that: The method for determining the pressure ratio of the supercharger according to the flow density entering the engine, the engine speed, the pressure after the intercooler, the temperature after the intercooler, and the pressure after the air filter includes: Determine the intake air flow rate into the cylinder based on the flow density entering the engine, the displacement of a single cylinder, the number of engine cylinders, and the engine speed; Determine the first bypass flow rate based on the pressure after the intercooler, the temperature after the intercooler, and the pressure after the air filter; Determine the supercharger flow rate according to the first bypass flow rate and the intake air flow rate entering the cylinder; Determine the supercharger outlet pressure based on the pressure after intercooling, the intake air flow into the cylinder, and the supercharger flow; Determine the supercharger inlet pressure based on the pressure after the air filter; Determine the pressure ratio based on the supercharger inlet pressure and supercharger outlet pressure.

3. The method for protecting turbocharger hardware based on dynamic density limitation according to claim 2, characterized in that: The method for determining the supercharger outlet temperature according to the air filter temperature and the pressure ratio includes: Determine the supercharger speed correction coefficient based on the temperature after the air filter; Determine the supercharger flow correction coefficient based on the supercharger speed correction coefficient and the temperature after the air filter; Determine the supercharger flow correction value according to the supercharger flow correction coefficient and the supercharger flow; Determine the efficiency of the supercharger based on the supercharger flow correction value and pressure ratio; Determine the supercharger outlet temperature based on the air filter temperature, pressure ratio, and supercharger efficiency.

4. The method for protecting turbocharger hardware based on dynamic density limitation according to claim 3, characterized in that: The method for determining the charging efficiency limit value according to the engine speed, the flow density entering the engine, and the charging efficiency includes: Determine the maximum charging efficiency based on the engine speed; Determine the engine gas volume deviation based on the flow density entering the engine; Determine the maximum charging efficiency weight according to the engine gas volume deviation and engine speed; The inflation efficiency limit value is determined based on the inflation efficiency and the weight of the maximum inflation efficiency ratio.

5. The method for protecting turbocharger hardware based on dynamic density limitation according to claim 1, characterized in that: The method for determining the pressure-limited air volume according to the engine speed and the charging efficiency limit value includes: Determine the maximum boost pressure limit value according to the engine speed; The pressure-limited air volume is determined according to the maximum boost pressure limit value, the charging efficiency limit value, and the temperature of the engine intake manifold; wherein the temperature of the engine intake manifold is obtained through detection.

6. The method for protecting turbocharger hardware based on dynamic density limitation according to claim 4, characterized in that: The method for determining the speed-limited air volume according to the charging efficiency limit value, the temperature of the engine intake manifold, the engine speed, the temperature after the air filter, the atmospheric pressure, the temperature after the intercooler, and the supercharger outlet temperature includes: Determining a pressure limit value at the intake manifold based on a charging efficiency limit value, a temperature of the engine intake manifold, and a weight of a maximum charging efficiency ratio; wherein the temperature of the engine intake manifold is obtained by detection; determining an engine intake air flow limit value according to the engine speed; Determine the air filter pressure drop based on the engine intake flow limit, air filter temperature, and atmospheric pressure; Determine the supercharger inlet pressure limit based on the air filter pressure drop; The second bypass flow is determined based on the intake manifold pressure limit, the supercharger inlet pressure limit, and the intercooler temperature. determining a supercharger flow limit value according to a second bypass flow rate and an engine intake flow limit value; Determine the supercharger outlet pressure limit value based on the intake manifold pressure limit value, engine intake flow limit value, and supercharger outlet temperature; Determine the predicted maximum limiting pressure ratio based on atmospheric pressure and supercharger flow correction value; Determine the supercharger outlet pressure deviation based on the supercharger outlet pressure and supercharger inlet pressure limits; Determine the outlet pressure based on the outlet pressure deviation of the supercharger; Determine the predicted limiting pressure ratio based on the outlet pressure and supercharger inlet pressure limit; Determine the predicted pressure ratio deviation according to the predicted maximum limit pressure ratio and the predicted limit pressure ratio; Determine the density increment step size based on the predicted pressure ratio deviation; The speed limiting gas volume is determined based on the density increment step.

7. The method for protecting turbocharger hardware based on dynamic density limitation according to claim 1, characterized in that: The method for determining the final air volume limiting density based on the pressure limiting air volume and the speed limiting air volume is as follows: The final air volume limit density is set to the smaller value of the speed limit air volume and the pressure limit air volume.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the booster hardware protection method based on dynamic density limitation according to any one of claims 1 to 7 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for protecting booster hardware based on dynamic density limitation according to any one of claims 1 to 7 are implemented.

10. An automobile, characterized in that: The automobile executes the steps of the supercharger hardware protection method based on dynamic density limitation as described in any one of claims 1 to 7.

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