A multi-dimensional intake density correction method for an EGR engine

Abstract

The application discloses an EGR engine multi-dimension intake density correction method, comprising the following steps: determining the intake manifold temperature according to the EGR installation mode, engine speed, intake camshaft angle, exhaust camshaft angle and final EGR mixed temperature; determining the intake and exhaust pressure ratio according to the throttle valve after gas temperature, throttle valve after gas pressure, atmospheric pressure and engine speed; determining the weighted after-charging efficiency according to the intake VVT angle, exhaust VVT angle, engine speed and intake and exhaust pressure ratio; determining the final charging efficiency according to the engine speed, throttle valve after gas pressure and weighted after-charging efficiency; and determining the total cylinder intake and fresh air flow in the cylinder according to the final charging efficiency, intake manifold temperature, engine speed, engine cylinder number and engine per cylinder volume. The method realizes accurate calculation of the EGR engine intake density.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of engine control, in particular to a multi-dimensional intake density correction method for EGR engine. BACKGROUND

[0002] The intake amount refers to the flow rate of the engine into the cylinder. In the current industry background of pursuing fuel consumption, VVT and EGR technologies have become a mainstream engine technology, and technical solutions such as Miller cycle for in-cylinder combustion have also begun to be widely used. These will all affect the intake amount of the engine. In order to achieve accurate control of the torque, the engine intake amount needs to be accurately calculated, and these influencing factors must be considered.

[0003] The prior art DE102012207890B4 discloses a method for determining the cylinder charge amount of an internal combustion engine, comprising: determining engine operating parameters; including intake charge density, engine pressure difference as the ratio of intake manifold pressure to exhaust pressure, and engine speed; determining the throttle opening volume efficiency corresponding to the engine operating parameters, and determining the throttle closing volume efficiency corresponding to the engine operating parameters; and determining the cylinder charge amount using one of the opening throttle volume efficiency and the closing throttle volume efficiency.

[0004] The prior art CN109268158A discloses a method for correcting the intake amount of an engine, comprising: calibrating different engine speeds and engine torques corresponding to the charge efficiency through a test bench to form a corresponding table of working conditions and charge efficiency, and storing the corresponding table in the engine ECU; setting a self-learning working condition, when the engine meets the self-learning working condition, calculating the theoretical intake amount of the engine according to the working condition of the engine and the corresponding table; collecting the actual intake amount of the engine through an air flow meter, taking the ratio of the theoretical intake amount of the engine to the actual intake amount of the engine as the flow correction coefficient; taking the flow correction coefficient as the correction value of the measured engine intake amount, and storing it in the engine ECU.

[0005] The defect of the above-mentioned prior art is that it does not consider the factors of different EGR installation positions, VVT systems, and Miller cycle intake backflow. SUMMARY

[0006] The purpose of the present application is to provide a multi-dimensional intake density correction method for EGR engine, so as to obtain accurate intake density of EGR engine.

[0007] To solve the above technical problems, the present application provides a multi-dimensional intake density correction method for EGR engine, comprising:

[0008] According to the EGR installation mode, the final EGR mixed temperature is determined.

[0009] Using an iterative method, the intake manifold temperature is determined based on engine speed, intake camshaft angle, exhaust camshaft angle, and final EGR mixture temperature; where engine speed, intake camshaft angle, and exhaust camshaft angle are all obtained through detection.

[0010] The intake and exhaust pressure ratio is determined based on the gas temperature after the throttle valve, the gas pressure after the throttle valve, atmospheric pressure, and engine speed; the gas temperature after the throttle valve, the gas pressure after the throttle valve, and atmospheric pressure are all obtained through detection.

[0011] The weighted charging efficiency is determined based on the intake VVT ​​angle, exhaust VVT angle, engine speed, and intake / exhaust pressure ratio; the intake VVT ​​angle and exhaust VVT angle are obtained through detection.

[0012] The final charging efficiency is determined based on engine speed, gas pressure after throttle, and weighted charging efficiency.

[0013] The total intake air volume and the fresh air flow rate in the cylinder are determined based on the final charging efficiency, intake manifold temperature, engine speed, number of engine cylinders, and volume per cylinder.

[0014] According to the above scheme, the method for determining the EGR mixing temperature based on the EGR installation method includes:

[0015] When the EGR is installed with the EGR outlet connected to the engine intake manifold, proceed with the following steps.

[0016] The temperature increase is determined based on the engine coolant temperature and the gas temperature after the throttle valve; the engine coolant temperature is obtained through detection.

[0017] Determine the corrected gas temperature based on the temperature increase and the gas temperature after the throttle valve.

[0018] The gas temperature after water temperature correction is low-pass filtered to obtain the filtered intake air temperature.

[0019] The exhaust gas flow rate is determined based on the value of the fresh air flow rate in the cylinder in the previous calculation cycle.

[0020] The final EGR mixing temperature is determined based on the comparison between the total intake air volume in the cylinder in the previous calculation cycle and the set minimum flow threshold, the fresh air flow rate and exhaust gas flow rate in the cylinder in the previous calculation cycle, and the intake air temperature after filtering.

[0021] According to the above scheme, the method for determining the EGR mixing temperature based on the EGR installation method includes:

[0022] When the EGR installation method is such that the EGR exhaust gas is mixed at the throttle body, proceed with the following steps;

[0023] Based on the total intake air volume in the cylinder in the previous calculation cycle, determine the fresh air flow rate and exhaust gas flow rate in the cylinder in the previous calculation cycle.

[0024] The EGR mixing temperature is determined by comparing the total intake air volume in the cylinder in the previous calculation cycle with the set minimum flow threshold.

[0025] Determine the amount of temperature increase based on the temperature after EGR mixing;

[0026] Determine the corrected gas temperature based on the increase in temperature.

[0027] The gas temperature after water temperature correction is low-pass filtered to obtain the filtered intake air temperature.

[0028] Set the final EGR mixture temperature to be equal to the filtered intake air temperature.

[0029] According to the above scheme, the method for determining the EGR mixing temperature based on the EGR installation method includes:

[0030] When the EGR system is installed with its outlet located after the engine air filter, and the air mixes with the atmosphere before entering the turbocharger, proceed with the following steps.

[0031] The temperature increase is determined based on the engine coolant temperature and the gas temperature after the throttle valve; the engine coolant temperature is obtained through detection.

[0032] Determine the corrected gas temperature based on the temperature increase and the gas temperature after the throttle valve.

[0033] The gas temperature after water temperature correction is low-pass filtered to obtain the filtered intake air temperature.

[0034] Set the final EGR mixture temperature to be equal to the filtered intake air temperature.

[0035] According to the above scheme, the method for determining the intake manifold temperature based on engine speed, in-cylinder fresh air flow rate in the previous calculation cycle, intake camshaft angle, exhaust camshaft angle, and final EGR mixture temperature includes:

[0036] Based on the engine speed and the in-cylinder fresh air flow rate of the previous calculation cycle, the first mixture temperature correction is obtained by looking up the table.

[0037] The intake and exhaust pressure ratio is determined based on the exhaust manifold pressure and the gas temperature after the throttle valve obtained through testing.

[0038] The second mixture temperature correction is obtained by referring to a table based on the engine speed and intake / exhaust pressure ratio.

[0039] Based on the intake camshaft angle and the exhaust camshaft angle, the third mixture temperature correction is obtained by referring to the table.

[0040] The in-cylinder gas correction temperature is determined based on the first mixing temperature correction, the second mixing temperature correction, and the third mixing temperature correction.

[0041] The second filter coefficient is determined based on the in-cylinder fresh air flow rate of the previous operation cycle;

[0042] The in-cylinder gas temperature is filtered according to the second filtering coefficient to obtain the filtered temperature increment.

[0043] The intake manifold temperature is determined based on the final EGR mixing temperature and the temperature increment after filtering.

[0044] According to the above scheme, the method for determining the intake and exhaust pressure ratio based on the gas temperature after the throttle valve, the gas pressure after the throttle valve, atmospheric pressure, and engine speed includes:

[0045] Determine the pressure ratio at altitude and at sea level based on the gas temperature and atmospheric pressure after the throttle valve.

[0046] The actual expansion ratio is obtained by referring to a table based on the pressure ratio at altitude and engine speed; the sea level expansion ratio is obtained by referring to a table based on the pressure ratio at sea level and engine speed.

[0047] The actual turbine pressure drop and the sea-level turbine pressure drop are determined based on the actual expansion ratio and the sea-level expansion ratio.

[0048] Determine the basic exhaust back pressure based on the actual turbine pressure drop and the turbine pressure drop at sea level;

[0049] Based on the current altitude, boost pressure ratio, engine speed, and atmospheric pressure, obtain the altitude correction factor from the table.

[0050] The final back pressure is determined based on the basic exhaust back pressure and the altitude correction factor.

[0051] The intake and exhaust pressure ratio is determined based on the final back pressure and the gas pressure after the throttle valve.

[0052] According to the above scheme, the method for determining the weighted charging efficiency based on the intake VVT ​​angle, exhaust VVT angle, engine speed, and intake / exhaust pressure ratio includes:

[0053] Based on the intake VVT ​​angle and exhaust VVT angle, determine the high reference position, low reference position, high reference position, and low reference position of the intake VVT ​​angle;

[0054] Based on the high reference position of the intake VVT ​​angle, the low reference position of the intake VVT ​​angle, the high reference position of the exhaust VVT angle, the low reference position of the exhaust VVT angle, the intake and exhaust pressure ratio, and the engine speed, the first combination charging efficiency, the second combination charging efficiency, the third combination charging efficiency, and the fourth combination charging efficiency are obtained by referring to the table.

[0055] Based on the intake VVT ​​angle, the high reference position of the intake VVT ​​angle, and the low reference position of the intake VVT ​​angle, determine the weighting coefficient of the high reference position of the intake VVT ​​angle and the weighting coefficient of the low reference position of the intake VVT ​​angle.

[0056] Based on the exhaust VVT angle, the high reference position of the exhaust VVT angle, and the low reference position of the exhaust VVT angle, determine the weighting coefficient of the high reference position of the exhaust VVT angle and the weighting coefficient of the low reference position of the exhaust VVT angle.

[0057] The weighted inflation efficiency is determined based on the inflation efficiency of the first combination, the inflation efficiency of the second combination, the inflation efficiency of the third combination, the inflation efficiency of the fourth combination, the weighting coefficient of the high reference position of the intake VVT ​​angle, the weighting coefficient of the low reference position of the intake VVT ​​angle, the weighting coefficient of the high reference position of the exhaust VVT angle, and the weighting coefficient of the low reference position of the exhaust VVT angle.

[0058] According to the above scheme, the method for determining the final charging efficiency based on engine speed, gas pressure after throttle, and weighted charging efficiency includes:

[0059] Based on the engine speed N_EngSpd and the in-cylinder fresh air flow rate in the previous calculation cycle, linear interpolation is performed to look up the table and obtain the exhaust pressure of the engine under standard operating conditions.

[0060] The first pressure ratio coefficient is determined based on the exhaust pressure and the gas pressure after the throttle valve during standard engine operating conditions.

[0061] The second pressure ratio coefficient is determined based on the final back pressure and the gas pressure after the throttle valve.

[0062] Based on engine speed and gas pressure after throttle, look up the table to obtain the correction factor;

[0063] The influence coefficient of back pressure on inflation efficiency is determined based on the correction factor, the first pressure ratio coefficient, and the second pressure ratio coefficient.

[0064] Based on the correction factor and the influence coefficient of back pressure on inflation efficiency, determine the final correction value of back pressure on inflation efficiency.

[0065] The final inflation efficiency is determined based on the weighted inflation efficiency and the final value of the correction for inflation efficiency by back pressure.

[0066] According to the above scheme, the method for determining the total intake air volume and the fresh air flow rate in the cylinder based on the final charging efficiency, intake manifold temperature, engine speed, number of engine cylinders, and volume per cylinder includes:

[0067] The total intake density of the gas entering the cylinder is determined based on the final charging efficiency, the gas pressure after the throttle valve, and the intake manifold temperature.

[0068] Determine the fresh air intake density based on the total intake density of the gas entering the cylinder;

[0069] The total intake air flow rate in the cylinder is determined based on the total intake air density of the gas entering the cylinder, engine speed, number of engine cylinders, and volume per cylinder.

[0070] The fresh air flow rate in each cylinder is determined based on the fresh air intake density, engine speed, number of engine cylinders, and volume per cylinder.

[0071] A computer device includes 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 steps of the multi-dimensional intake density correction method for EGR engines described above.

[0072] The beneficial effects of this invention are: it calculates the air-fuel mixture temperature using different methods for EGR engines with different installation positions; it corrects for the intake temperature based on the in-cylinder gas backflow caused by late intake valve closing due to camshaft position; and it calculates and corrects the charging efficiency based on the effects of different altitudes, camshaft positions, and exhaust back pressure on charging efficiency. Finally, it calculates the flow rate and density of the gas entering the cylinder, improving the accuracy of intake volume calculation and torque control. Attached Figure Description

[0073] Figure 1 This is a flowchart of the multi-dimensional intake density correction method for an EGR engine according to Embodiment 1 of the present invention. Detailed Implementation

[0074] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0075] Example 1:

[0076] See Figure 1 This embodiment discloses a multi-dimensional intake density correction method for an EGR engine, including the following steps:

[0077] S1. Determine the EGR mixing temperature based on the EGR installation method;

[0078] S1 specifically includes the following steps:

[0079] S101. When the EGR installation method is: the EGR outlet is the engine intake manifold, this step is performed; at this time, the fresh gas is first heated by the coolant temperature, and then the heat is mixed; S101 includes:

[0080] The temperature increase T_WT_TempAirIncrease is determined based on the engine coolant temperature T_EngineCoolant and the gas temperature after the throttle valve T_IntakeManifold.

[0081] T_WT_TempAirIncrease=(T_EngineCoolant-T_IntakeManifold)*K_WT_WallTransfer / DM_CylinderAirFlow(z)

[0082] Where K_WT_WallTransfer is the heat transfer coefficient, which is an inherent characteristic, and is set to 0.5 in this example; DM_CylinderAirFlow(z) is the final calculated total in-cylinder intake air volume DM_CylinderAirFlow value in the previous calculation cycle, and this value is a stored value; engine coolant temperature T_EngineCoolant and throttle body gas temperature T_IntakeManifold are obtained by measuring through corresponding sensors;

[0083] Based on the temperature increase T_WT_TempAirIncrease and the gas temperature after throttle valve T_IntakeManifold, determine the gas temperature T_WT_AirTempBefEGR after water temperature correction.

[0084] T_WT_AirTempBefEGR=T_IntakeManifold+T_WT_TempAirIncrease

[0085] The gas temperature T_WT_AirTempBefEGR after water temperature correction is low-pass filtered to obtain the filtered intake air temperature T_WT_AirTempBefEGRFlt.

[0086] T_WT_AirTempBefEGRFlt

[0087] =K_WT_PortTempFilt*T_WT_AirTempBefEGR

[0088] +(1-K_WT_PortTempFilt)*T_WT_AirTempBefEGRFlt(Z)

[0089] In the above formula, T_WT_AirTempBefEGRFlt(Z) is the value of the filtered intake air temperature T_WT_AirTempBefEGRFlt in the previous calculation cycle, and K_WT_PortTempFilt is the first filtering coefficient, which is 0.5 in this embodiment;

[0090] Based on the in-cylinder fresh air flow rate DM_CylinderAirFlow(z) of the previous calculation cycle, determine the exhaust gas flow rate DM_EGR;

[0091] DM_EGR=EGR_ExtActual*DM_CylinderAirFlow(z) / (1-EGR_ExtActual)

[0092] In the above formula, EGR_ExtActual is the EGR rate obtained through detection;

[0093] Based on the comparison between the final calculated total in-cylinder intake volume DM_CylinderGasFlow(z) in the previous calculation cycle and the set minimum flow threshold, the in-cylinder fresh air flow DM_CylinderAirFlow(z) and exhaust gas flow DM_EGR in the previous calculation cycle, and the filtered intake temperature T_WT_AirTempBefEGRFlt, the EGR mixing temperature T_PT_AfterEGRBlend is determined.

[0094] If DM_CylinderGasFlow(z) is less than the minimum flow threshold (0.05 g / s in this example), then:

[0095] T_PT_AfterEGRBlend=T_WT_AirTempBefEGRFlt

[0096] If DM_CylinderGasFlow(z) is not less than the minimum flow threshold, then:

[0097]

[0098] In the above formula, T_EGRatMixPoint is the EGR outlet temperature obtained by detection;

[0099] Set the final EGR mixing temperature T_PT_PortTempEGR to equal T_PT_AfterEGRBlend;

[0100] S102. When the EGR installation method is: the EGR exhaust gas mixes at the throttle body, this step is executed; at this time, the fresh gas first undergoes heat mixing, and then is heated by the coolant temperature; S102 includes:

[0101] Based on the fresh air flow rate DM_CylinderAirFlow(z) of the previous calculation cycle, determine the exhaust gas flow rate DM_EGR;

[0102] DM_EGR=EGR_ExtActual*DM_CylinderAirFlow(z) / (1-EGR_ExtActual)

[0103] In the above formula, EGR_ExtActual is the EGR rate obtained through detection;

[0104] Based on the comparison between the final calculated total in-cylinder intake volume DM_CylinderGasFlow(z) in the previous calculation cycle and the set minimum flow threshold, the EGR mixing temperature T_PT_AfterEGRBlend is determined.

[0105] If DM_CylinderGasFlow((z)) is less than the minimum flow threshold (0.05 g / s in this example), then:

[0106] T_PT_AfterEGRBlend=T_IntakeManifold

[0107] If DM_CylinderGasFlow(z) is not less than the minimum flow threshold, then:

[0108]

[0109] The temperature increase T_WT_TempAirIncrease is determined based on the EGR mixing temperature T_PT_AfterEGRBlend.

[0110] T_WT_TempAirIncrease=(T_EngineCoolant-T_PT_AfterEGRBlend)*K_WT_WallTransfer / DM_CylinderGasFlow(z)

[0111] Determine the corrected gas temperature T_WT_AirTempBefEGR based on the temperature increase T_WT_TempAirIncrease.

[0112] T_WT_AirTempBefEGR=T_PT_AfterEGRBlend+T_WT_TempAirIncrease

[0113] The gas temperature T_WT_AirTempBefEGR after water temperature correction is low-pass filtered to obtain the filtered intake air temperature T_WT_AirTempBefEGRFlt.

[0114] T_WT_AirTempBefEGRFlt

[0115] =K_WT_PortTempFilt*T_WT_AirTempBefEGR

[0116] +(1-K_WT_PortTempFilt)*T_WT_AirTempBefEGRFlt(Z)

[0117] Set the final EGR mixing temperature T_PT_PortTempEGR to equal the filtered intake air temperature T_WT_AirTempBefEGRFlt;

[0118] S103. When the EGR system is installed as follows: the EGR system outlet is after the engine air filter, and the air mixes with the atmosphere before entering the turbocharger; in this case, since the air entering the turbocharger is already mixed, only coolant heating is needed in the manifold; S103 includes:

[0119] The temperature increase T_WT_TempAirIncrease is determined based on the engine coolant temperature T_EngineCoolant and the gas temperature after the throttle valve T_IntakeManifold.

[0120] T_WT_TempAirIncrease=(T_EngineCoolant-T_IntakeManifold)*K_WT_WallTransfer / DM_CylinderAirFlow(Z)

[0121] Based on the temperature increase T_WT_TempAirIncrease and the gas temperature after throttle valve T_IntakeManifold, determine the gas temperature T_WT_AirTempBefEGR after water temperature correction.

[0122] The gas temperature T_WT_AirTempBefEGR after water temperature correction is low-pass filtered to obtain the filtered intake air temperature T_WT_AirTempBefEGRFlt.

[0123] T_WT_AirTempBefEGRFlt

[0124] =K_WT_PortTempFilt*T_WT_AirTempBefEGR

[0125] +(1-K_WT_PortTempFilt)*T_WT_AirTempBefEGRFlt(Z)

[0126] Set the final EGR mixing temperature T_PT_PortTempEGR to be equal to the filtered intake temperature T_WT_AirTempBefEGRFlt.

[0127] S2. Determine the intake manifold temperature based on engine speed, in-cylinder fresh air flow rate in the previous calculation cycle, intake camshaft angle, exhaust camshaft angle, and final EGR mixture temperature; where engine speed, intake camshaft angle, and exhaust camshaft angle are obtained through detection.

[0128] S2 specifically includes the following steps:

[0129] S201. Based on the engine speed N_EngSpd and the in-cylinder fresh air flow rate DM_CylinderAirFlow(z) of the previous calculation cycle, look up the table to obtain the first mixing temperature correction T_PT_BF_SpdLdDeltaTemp;

[0130] The table used is as follows:

[0131]

[0132] T_PT_BF_SpdLdDeltaTemp satisfies:

[0133] T_PT_BF_SpdLdDeltaTemp=T_intakeAir_VVToff_BaseBackpress_EGR / T_intakeBase

[0134] In the above formula, T_intakeAir_VVToff_BaseBackpress_EGR is the inlet gas temperature under the conditions of VVT not being engaged, using standard exhaust back pressure, and EGR being used. This value is obtained by looking up a table based on the engine speed N_EngSpd and the in-cylinder fresh air flow rate DM_CylinderAirFlow(z) of the previous calculation cycle; T_intakeBase is the inlet gas temperature under the conditions of VVT not being engaged, using standard exhaust back pressure, and EGR not being used. This value is obtained by looking up a table based on the engine speed N_EngSpd and the in-cylinder fresh air flow rate DM_CylinderAirFlow(z) of the previous calculation cycle.

[0135] S202. Determine the intake and exhaust pressure ratio R_Intake_Exh based on the exhaust manifold pressure P_ExhMan and the gas temperature T_IntakeManifold after the throttle valve obtained by detection.

[0136] R_Intake_Exh=P_ExhMan / P_IntakeManifold

[0137] S203. Based on the engine speed N_EngSpd and the intake and exhaust pressure ratio R_Intake_Exh, look up the table to obtain the second mixing temperature correction T_PT_BF_PrRatioDeltaTemp;

[0138] The table used is as follows:

[0139]

[0140] T_PT_BF_PrRatioDeltaTemp satisfies:

[0141] T_PT_BF_PrRatioDeltaTemp=T_intakeAir_VVToff_Backpress_EGR-T_intakeBase

[0142] S204. Based on the intake camshaft angle PHI_IntkCamPos and the exhaust camshaft angle PHI_ExhCamPos, look up the table to obtain the third mixing temperature correction R_PT_BF_CamGain.

[0143] The table used is as follows:

[0144]

[0145] R_PT_BF_CamGain satisfies:

[0146] R_PT_BF_CamGain=T_intakeAir_VVTon_BaseBackpress_EGR / T_intakeAir_VVToff_Backpress_EGR

[0147] In the above formula, T_intakeAir_VVTon_BaseBackpress_EGR is the temperature of the gas entering the cylinder under the conditions of VVT being on, using standard exhaust back pressure, and EGR being used. This value is obtained by looking up a table based on the engine speed N_EngSpd and the in-cylinder fresh air flow rate DM_CylinderAirFlow(z) of the previous calculation cycle.

[0148] S205. Determine the in-cylinder gas correction temperature T_PT_BF_LdIcamUnflt based on the first mixing temperature correction T_PT_BF_SpdLdDeltaTemp, the second mixing temperature correction T_PT_BF_PrRatioDeltaTemp, and the third mixing temperature correction R_PT_BF_CamGain.

[0149] T_PT_BF_LdIcamUnflt

[0150] =R_PT_BF_CamGain(T_PT_BF_PrRatioDeltaTemp

[0151] +T_PT_BF_SpdLdDeltaTemp)

[0152] S206. Determine the second filter coefficient K_WT_CylinderTempFilt based on the in-cylinder fresh air flow rate DM_CylinderAirFlow(z) of the previous operation cycle.

[0153] Based on the in-cylinder fresh air flow rate DM_CylinderAirFlow(z) of the previous calculation cycle, look up the table to obtain the second filter coefficient K_WT_CylinderTempFilt;

[0154] The table used is as follows:

[0155]

[0156] S207. Filter the in-cylinder gas correction temperature T_PT_BF_LdIcamUnflt according to the second filtering coefficient K_WT_CylinderTempFilt to obtain the filtered temperature increment T_PT_BF_TempIncr.

[0157] T_PT_BF_TempIncr

[0158] =K_WT_CylinderTempFilt*T_PT_BF_LdIcamUnflt

[0159] +(1-K_WT_CylinderTempFilt)*T_PT_BF_TempIncr(Z)

[0160] In the above formula, T_PT_BF_TempIncr(Z) is the value of the filtered temperature increment T_PT_BF_TempIncr in the previous calculation cycle;

[0161] S208. Determine the intake manifold temperature TK_PortTempInternal based on the final EGR mixing temperature T_PT_PortTempEGR and the filtered temperature increment T_PT_BF_TempIncr.

[0162] TK_PortTempInternal=273K+T_PT_PortTempEGR+T_PT_BF_TempIncr

[0163] S3. Determine the intake and exhaust pressure ratio based on the gas temperature after the throttle valve, the gas pressure after the throttle valve, atmospheric pressure, and engine speed; the gas temperature after the throttle valve, the gas pressure after the throttle valve, and atmospheric pressure are all obtained through detection.

[0164] S3 specifically includes the following steps:

[0165] S301. Determine the current altitude boost pressure ratio R_IntakeRatioCurr and sea level boost pressure ratio R_IntakeRatioSL based on the gas temperature T_IntakeManifold after the throttle and the atmospheric pressure P_Ambient.

[0166] R_IntakeRatioCurr=P_IntakeManifold / P_Ambient

[0167] R_IntakeRatioSL=P_IntakeManifold / 100kpa

[0168] Among them, atmospheric pressure P_Ambient is obtained by sensor detection, and 100 kPa represents standard atmospheric pressure;

[0169] S302. Based on the current altitude pressurization ratio R_IntakeRatioCurr and engine speed N_EngSpd, look up the table to obtain the actual expansion ratio R_TurbExpRatioCurr; based on the sea level pressurization ratio R_IntakeRatioSL and engine speed N_EngSpd, look up the table to obtain the sea level expansion ratio R_TurbExpRatioSL.

[0170] The table used is as follows:

[0171]

[0172] Among them, R_IntakeRatio_Base can take the value of the current altitude pressure ratio R_IntakeRatioCurr or the sea level pressure ratio R_IntakeRatioSL according to actual needs. The corresponding table lookup results are the actual expansion ratio R_TurbExpRatioCurr and the sea level expansion ratio R_TurbExpRatioSL, respectively.

[0173] S303. Determine the actual turbine pressure drop P_TurbPressDropCurr and the sea-level turbine pressure drop P_TurbPressDropSL based on the actual expansion ratio R_TurbExpRatioCurr and the sea-level expansion ratio R_TurbExpRatioSL.

[0174] P_TurbPressDropCurr=R_TurbExpRatioCurr*P_Ambient-P_Ambient

[0175] P_TurbPressDropSL=R_TurbExpRatioSL*100kpa-100kpa

[0176] S304. Determine the basic exhaust back pressure P_BackPressEst based on the actual turbine pressure drop P_TurbPressDropCurr and the sea-level turbine pressure drop P_TurbPressDropSL.

[0177] P_BackPressEst=P_TurbPressDropCurr-P_TurbPressDropSL+P_Ambient

[0178] S305. Based on the current altitude boost pressure ratio R_IntakeRatioCurr, engine speed N_EngSpd, and atmospheric pressure P_Ambient, look up the table to obtain the altitude correction factor K_Weight;

[0179] The corresponding tables for atmospheric pressure P_Ambient of 50 kPa, 65 kPa, 80 kPa, and 95 kPa are as follows:

[0180]

[0181]

[0182]

[0183]

[0184] First, determine which two of the four pressure values ​​(50 kPa, 65 kPa, 80 kPa, and 95 kPa) the atmospheric pressure P_Ambient falls between, and then determine the weighting factor Fact.

[0185] For example: if the atmospheric pressure P_Ambient is between 65 kPa and 80 kPa, the weighting factor Fact = (P_Ambientr - 65 kPa) / (80 kPa - 65 kPa);

[0186] Then, in the tables corresponding to the two selected pressure values, the table is looked up according to the current altitude boost pressure ratio R_IntakeRatioCurr and engine speed N_EngSpd. The table lookup result for the lower pressure value is WeightLow, and the table lookup result for the higher pressure value is WeightHigh. The altitude correction factor K_Weight = Fact * WeightLow + (1 - Fact)

[0187] *WeightHigh;

[0188] S306. Determine the final back pressure P_BackPressPointer based on the basic exhaust back pressure P_BackPressEst and the altitude correction factor K_Weight.

[0189] P_BackPressPointer=100kpa+(P_BackPressEst-100kpa)*K_Weight

[0190] S307. Determine the intake and exhaust pressure ratio R_PR based on the final back pressure P_BackPressPointer and the gas pressure after the throttle valve P_IntakeManifold.

[0191] R_PR=P_IntakeManifold / P_BackPressPointer

[0192] S4. Determine the weighted charging efficiency based on the intake VVT ​​angle, exhaust VVT angle, engine speed, and intake / exhaust pressure ratio; where the intake VVT ​​angle and exhaust VVT angle are obtained through detection.

[0193] S4 specifically includes the following steps:

[0194] S401. Based on the intake VVT ​​angle PHI_IntkCamPos and the exhaust VVT angle PHI_ExhkCamPos, determine the high reference position, low reference position, high reference position, and low reference position of the intake VVT ​​angle.

[0195] The intake VVT ​​angle PHI_IntkCamPos is compared with the value in the preset intake VVT ​​angle position group to determine which two adjacent values ​​in the intake VVT ​​angle position group the intake VVT ​​angle PHI_IntkCamPos is located between. These two adjacent values ​​in the intake VVT ​​angle position group are used as the intake VVT ​​angle high reference position PHI_VVTInhigh and intake VVT ​​angle low reference position PHI_VVTInlow.

[0196] The exhaust VVT angle PHI_ExhkCamPos is compared with the value in the preset exhaust VVT angle position group to determine which two adjacent values ​​in the exhaust VVT angle position group the exhaust VVT angle PHI_ExhkCamPos is located between. These two adjacent values ​​in the exhaust VVT angle position group are used as the exhaust VVT angle high reference position PHI_VVTExhhigh and exhaust VVT angle low reference position PHI_VVTExhlow.

[0197] Among them, the values ​​in the intake VVT ​​angle position group are divided by the intake VVT ​​angle range, and the values ​​in the exhaust VVT angle position group are divided by the exhaust VVT angle range.

[0198] For example: The intake VVT ​​angle range and the exhaust VVT angle range are both 0° to 50°. By taking points at fixed intervals, the resulting intake VVT ​​angle position group and exhaust VVT angle position group are both represented as PHI_Pstn=[0°,10°,20°,30°,40°,50°].

[0199] If the current intake VVT ​​angle PHI_IntkCamPos = 25°, and 25° is located between 20° and 30° in the intake VVT ​​angle position group, then 20° is the intake VVT ​​angle low reference position PHI_VVTInlow, and 30° is the intake VVT ​​angle high reference position PHI_VVTInhigh.

[0200] S402. Based on the intake VVT ​​angle high reference position PHI_VVTInhigh, intake VVT ​​angle low reference position PHI_VVTInlow, exhaust VVT angle high reference position PHI_VVTExhhigh, exhaust VVT angle low reference position PHI_VVTExhlow, intake and exhaust pressure ratio R_PR, and engine speed N_EngSpd, look up the table to obtain the first combination charging efficiency R_VolEff_Inlow_Exhlow, the second combination charging efficiency R_VolEff_Inlow_Exhhigh, the third combination charging efficiency R_VolEff_Inhigh_Exhlow, and the fourth combination charging efficiency R_VolEff_Inhigh_Exhhigh.

[0201] The table used in this step is obtained by combining each value in the intake VVT ​​angle position group with each value in the exhaust VVT angle position group in pairs to obtain several intake and exhaust VVT angle position combinations. The intake and exhaust pressure ratio R_PR, engine speed N_EngSpd, and charging efficiency R_VolEff under different intake and exhaust VVT angle position combinations are calibrated.

[0202] For example, the intake VVT ​​angle position group and the exhaust VVT angle position group are both represented as PHI_Pstn=[0°,10°,20°,30°,40°,50°], so 6*6=36 intake and exhaust VVT angle position combinations can be obtained, and thus 36 calibration tables can be obtained.

[0203] When the intake position in the intake and exhaust VVT angle position combination is the intake VVT ​​angle low reference position PHI_VVTInlow, and the exhaust VVT angle position is the exhaust VVT angle low reference position PHI_VVTExhlow, then after looking up the corresponding calibration table for this intake and exhaust VVT angle position combination, the obtained charging efficiency R_VolEff is represented as the first combination charging efficiency R_VolEff_Inlow_Exhlow; the charging efficiency R_VolEff_Inlow_Exhhigh, the third combination charging efficiency R_VolEff_Inhigh_Exhlow, and the fourth combination charging efficiency R_VolEff_Inhigh_Exhhigh are obtained in the same way;

[0204] S403. Based on the intake VVT ​​angle PHI_IntkCamPos, the high reference position of the intake VVT ​​angle PHI_VVTInhigh, and the low reference position of the intake VVT ​​angle PHI_VVTInlow, determine the weighting coefficient R_IC_Coeff_high and the weighting coefficient R_IC_Coeff_low for the high reference position of the intake VVT ​​angle and the low reference position of the intake VVT ​​angle.

[0205] R_IC_Coeff_high=(PHI_IntkCamPos-PHI_VVTInlow) / (PHI_VVTInhigh-PHI_VVTInlow)

[0206] R_IC_Coeff_low=1-R_IC_Coeff_high

[0207] S404. Based on the exhaust VVT angle PHI_ExhkCamPos, the exhaust VVT angle high reference position PHI_VVTExhhigh, and the exhaust VVT angle low reference position PHI_VVTExhlow, determine the exhaust VVT angle high reference position weight coefficient R_EC_Coeff_high and the exhaust VVT angle low reference position weight coefficient R_EC_Coeff_low.

[0208] R_EC_Coeff_high=(PHI_ExhkCamPos-PHI_VVTExhlow) / (PHI_VVTExhhigh-PHI_VVTExhlow).

[0209] R_EC_Coeff_low=1-R_EC_Coeff_high

[0210] S405. Based on the first combination inflation efficiency R_VolEff_Inlow_Exhlow, the second combination inflation efficiency R_VolEff_Inlow_Exhhigh, the third combination inflation efficiency R_VolEff_Inhigh_Exhlow, the fourth combination inflation efficiency R_VolEff_Inhigh_Exhhigh, the intake VVT ​​angle high reference position weighting coefficient R_IC_Coeff_high, the intake VVT ​​angle low reference position weighting coefficient R_IC_Coeff_low, the exhaust VVT angle high reference position weighting coefficient R_EC_Coeff_high, and the exhaust VVT angle low reference position weighting coefficient R_EC_Coeff_low, determine the weighted inflation efficiency VE_VVT_base.

[0211] VE_VVT_base=

[0212] R_VolEff_Inlow_Exhlow*R_IC_Coeff_low*R_EC_Coeff_low+

[0213] R_VolEff_Inlow_Exhhigh*R_IC_Coeff_low*R_EC_Coeff_high+

[0214] R_VolEff_Inhigh_Exhlow*R_IC_Coeff_high*R_EC_Coeff_low+

[0215] R_VolEff_Inlow_Exhhigh*R_IC_Coeff_high*R_EC_Coeff_high

[0216] S5. Determine the final charging efficiency based on engine speed, gas pressure after throttle, and weighted charging efficiency.

[0217] S5 specifically includes the following steps:

[0218] S501. Based on the engine speed N_EngSpd and the fresh air intake density RHO_CylAir(z) of the previous calculation cycle, perform linear interpolation to look up the table and obtain the exhaust pressure P_exhNorm of the engine under standard operating conditions.

[0219] The table used in this step is shown below:

[0220]

[0221] S502. Determine the first pressure ratio coefficient p_enom based on the exhaust pressure P_exhNorm and the gas pressure after the throttle valve (intake manifold pressure) P_IntakeManifold under standard engine operating conditions.

[0222] p_enom=P_exhNorm / P_IntakeManifold

[0223] S503. Determine the second pressure ratio coefficient p_eact based on the final back pressure P_BackPressPointer and the gas pressure after the throttle valve P_IntakeManifold.

[0224] p_eact=P_BackPressPointer / P_IntakeManifold

[0225] S504. Based on the engine speed N_EngSpd and the gas pressure after the throttle valve P_IntakeManifold, look up the table to obtain the correction factor K_VE_Gain;

[0226] The table used is as follows:

[0227]

[0228] S505. Determine the influence coefficient DVEBP_Inv of back pressure on inflation efficiency based on the correction factor K_VE_Gain, the first pressure ratio coefficient p_enom, and the second pressure ratio coefficient p_eact.

[0229] DVEBP_Inv=((p_enom)^(1 / gamma_e)-(p_eact)^(1 / gamma_e))

[0230] *K_VE_Gain

[0231] In the above formula, gamma_e is the exponential factor of the natural base, which is taken as a constant of 0.8 in this example;

[0232] S506. Based on the correction factor K_VE_Gain and the influence coefficient of back pressure on inflation efficiency DVEBP_Inv, determine the final correction value R_RawDeltaVE for back pressure on inflation efficiency.

[0233] R_RawDeltaVE=K_VE_Gain*DVEBP_Inv

[0234] S507. Determine the final inflation efficiency VE based on the weighted inflation efficiency VE_VVT_base and the final value of the back pressure correction to the inflation efficiency R_RawDeltaVE.

[0235] VE = VE_VVT_base + R_RawDeltaVE

[0236] S6. Determine the total intake air volume and fresh air flow rate in the cylinder based on the final charging efficiency, intake manifold temperature, engine speed, number of engine cylinders, and volume per cylinder.

[0237] S6 specifically includes the following steps:

[0238] S601. Determine the total intake density RHO_CylGas of the gas entering the cylinder based on the final charging efficiency VE, the gas pressure after the throttle valve P_IntakeManifold, and the intake manifold temperature TK_PortTempInternal.

[0239] RHO_CylGas=VE*P_IntakeManifold / (R*TK_PortTempInternal)

[0240] In the above formula, R is the gas constant, which is taken as 0.00347 in this example;

[0241] S602. Determine the fresh air intake density RHO_CylAir based on the total intake density RHO_CylGas of the gas entering the cylinder.

[0242] RHO_CylAir=RHO_CylGas*(1-EGR_ExtActual)

[0243] S603. Determine the total intake air flow rate DM_CylinderGasFlow based on the total intake air density RHO_CylGas, engine speed N_EngSpd, number of engine cylinders Cnt_Cyl, and engine volume per cylinder V_Cyl.

[0244] DM_CylinderGasFlow=RHO_CylGas*N_EngSpd*Cnt_Cyl*V_Cyl

[0245] It should be understood that the number of engine cylinders Cnt_Cyl and the volume per cylinder V_Cyl are inherent parameters of the engine. In this embodiment, the number of engine cylinders Cnt_Cyl is 4 and the volume per cylinder V_Cyl is 0.37L.

[0246] S604. Determine the in-cylinder fresh air flow rate DM_CylinderAirFlow based on the fresh air intake density RHO_CylAir, engine speed N_EngSpd, number of engine cylinders Cnt_Cyl, and engine volume per cylinder V_Cyl.

[0247] DM_CylinderGasFlow=RHO_CylAir*N_EngSpd*Cnt_Cyl*V_Cyl

[0248] Example 2:

[0249] This embodiment discloses a computer device for implementing the method described in Embodiment 1. The computer device may be a smartphone, tablet computer, laptop computer, desktop computer, rack server, blade server, tower server, or cabinet server (including standalone servers or server clusters composed of multiple servers) capable of executing programs. The computer device of this embodiment includes, but is not limited to, a memory and a processor that can be communicatively connected to each other via a system bus. It should be noted that only a computer device with components is shown; however, it should be understood that it is not required to implement all the shown components, and more or fewer components may be implemented alternatively.

[0250] In this embodiment, the memory (i.e., the 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 can also be an external storage device of the computer device, such as a plug-in hard disk, smart media card (SMC), secure digital card (SD), flash card, etc., provided on the computer device. Of course, the memory can also include both internal storage units and external storage devices of the computer device. In this embodiment, the memory is typically used to store the operating system and various application software installed on the computer device, such as the program code for the EGR engine multi-dimensional intake density correction method in Embodiment 1. Furthermore, the memory can also be used to temporarily store various types of data that have been output or will be output.

[0251] 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 run program code stored in memory or process data, such as running a multi-dimensional intake density correction method for an EGR engine.

[0252] Example 3:

[0253] This embodiment provides a computer-readable storage medium, such as 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), programmable read-only memory (PROM), magnetic memory, disk, optical disk, server, app store, etc., which stores computer programs. When the program is executed by a processor, it implements the corresponding functions. In this embodiment, the computer-readable storage medium is used to store the program code for a multi-dimensional intake density correction method for an EGR engine. When executed by a processor, it implements the multi-dimensional intake density correction method for an EGR engine as described in Embodiment 1.

[0254] Example 4:

[0255] This embodiment provides a car that performs the EGR engine multi-dimensional intake density correction method described in Embodiment 1.

[0256] It should be understood that the sequence number of each step in the above embodiments does not imply 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.

[0257] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0258] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for multi-dimensional intake air density correction in an EGR engine, characterized in that, include: Determine the final EGR mixing temperature based on the EGR installation method; The intake manifold temperature is determined based on engine speed, intake camshaft angle, exhaust camshaft angle, and final EGR mixture temperature; engine speed, intake camshaft angle, and exhaust camshaft angle are all obtained through testing. The intake and exhaust pressure ratio is determined based on the gas temperature after the throttle valve, the gas pressure after the throttle valve, atmospheric pressure, and engine speed; the gas temperature after the throttle valve, the gas pressure after the throttle valve, and atmospheric pressure are all obtained through detection. The weighted charging efficiency is determined based on the intake VVT ​​angle, exhaust VVT angle, engine speed, and intake / exhaust pressure ratio; the intake VVT ​​angle and exhaust VVT angle are obtained through detection. The final charging efficiency is determined based on engine speed, gas pressure after throttle, and weighted charging efficiency. Determine the total in-cylinder intake volume and in-cylinder fresh air flow rate based on the final charging efficiency, intake manifold temperature, engine speed, number of engine cylinders, and engine volume per cylinder. The method for determining the total in-cylinder intake volume and in-cylinder fresh air flow rate based on the final charging efficiency, intake manifold temperature, engine speed, number of engine cylinders, and engine volume per cylinder includes: The total intake density of the gas entering the cylinder is determined based on the final charging efficiency, the gas pressure after the throttle valve, and the intake manifold temperature. Determine the fresh air intake density based on the total intake density of the gas entering the cylinder; The total intake air flow rate in the cylinder is determined based on the total intake air density of the gas entering the cylinder, engine speed, number of engine cylinders, and volume per cylinder. The fresh air flow rate in each cylinder is determined based on the fresh air intake density, engine speed, number of engine cylinders, and volume per cylinder.

2. The multi-dimensional intake density correction method for an EGR engine according to claim 1, characterized in that, The method for determining the EGR mixing temperature based on the EGR installation method includes: When the EGR is installed with the EGR outlet connected to the engine intake manifold, proceed with the following steps. The temperature increase is determined based on the engine coolant temperature and the gas temperature after the throttle valve; the engine coolant temperature is obtained through detection. Determine the corrected gas temperature based on the temperature increase and the gas temperature after the throttle valve. The gas temperature after water temperature correction is low-pass filtered to obtain the filtered intake air temperature. The exhaust gas flow rate is determined based on the value of the fresh air flow rate in the cylinder in the previous calculation cycle; The final EGR mixing temperature is determined based on the comparison between the total intake air volume in the cylinder in the previous calculation cycle and the set minimum flow threshold, the fresh air flow rate and exhaust gas flow rate in the cylinder in the previous calculation cycle, and the intake air temperature after filtering.

3. The multi-dimensional intake density correction method for an EGR engine according to claim 1, characterized in that, The method for determining the EGR mixing temperature based on the EGR installation method includes: When the EGR installation method is such that the EGR exhaust gas is mixed at the throttle body, proceed with the following steps; Based on the total intake air volume in the cylinder in the previous calculation cycle, determine the fresh air flow rate and exhaust gas flow rate in the cylinder in the previous calculation cycle. The EGR mixing temperature is determined by comparing the total intake air volume in the cylinder in the previous calculation cycle with the set minimum flow threshold. Determine the amount of temperature increase based on the temperature after EGR mixing; Determine the corrected gas temperature based on the increase in temperature. The gas temperature after water temperature correction is low-pass filtered to obtain the filtered intake air temperature. Set the final EGR mixture temperature to be equal to the filtered intake air temperature.

4. The multi-dimensional intake density correction method for an EGR engine according to claim 1, characterized in that, The method for determining the EGR mixing temperature based on the EGR installation method includes: When the EGR system is installed with its outlet located after the engine air filter, and the air mixes with the atmosphere before entering the turbocharger, proceed with the following steps. The temperature increase is determined based on the engine coolant temperature and the gas temperature after the throttle valve; the engine coolant temperature is obtained through detection. Determine the corrected gas temperature based on the temperature increase and the gas temperature after the throttle valve. The gas temperature after water temperature correction is low-pass filtered to obtain the filtered intake air temperature. Set the final EGR mixture temperature to be equal to the filtered intake air temperature.

5. The multi-dimensional intake density correction method for an EGR engine according to claim 1, characterized in that, The method for determining the intake manifold temperature based on engine speed, intake camshaft angle, exhaust camshaft angle, and final EGR mixture temperature includes: Based on the engine speed and the in-cylinder fresh air flow rate of the previous calculation cycle, the first mixture temperature correction is obtained by looking up the table. The second intake and exhaust pressure ratio is determined based on the exhaust manifold pressure and the gas pressure after the throttle valve obtained by detection. Based on the engine speed and the second intake and exhaust pressure ratio, the second mixture temperature correction is obtained by referring to the table. Based on the intake camshaft angle and the exhaust camshaft angle, the third mixture temperature correction is obtained by referring to the table. The in-cylinder gas correction temperature is determined based on the first mixing temperature correction, the second mixing temperature correction, and the third mixing temperature correction. The second filter coefficient is determined based on the in-cylinder fresh air flow rate of the previous operation cycle; The in-cylinder gas temperature is filtered according to the second filtering coefficient to obtain the filtered temperature increment. The intake manifold temperature is determined based on the final EGR mixing temperature and the temperature increment after filtering.

6. The multi-dimensional intake density correction method for an EGR engine according to claim 1, characterized in that, The method for determining the intake and exhaust pressure ratio based on the gas temperature after the throttle valve, the gas pressure after the throttle valve, atmospheric pressure, and engine speed includes: Determine the pressure ratio at altitude and at sea level based on the gas temperature and atmospheric pressure after the throttle valve. The actual expansion ratio is obtained by referring to a table based on the pressure ratio at altitude and engine speed; the sea level expansion ratio is obtained by referring to a table based on the pressure ratio at sea level and engine speed. The actual turbine pressure drop and the sea-level turbine pressure drop are determined based on the actual expansion ratio and the sea-level expansion ratio. Determine the basic exhaust back pressure based on the actual turbine pressure drop and the turbine pressure drop at sea level; Based on the current altitude, boost pressure ratio, engine speed, and atmospheric pressure, obtain the altitude correction factor from the table. The final back pressure is determined based on the basic exhaust back pressure and the altitude correction factor. The intake and exhaust pressure ratio is determined based on the final back pressure and the gas pressure after the throttle valve.

7. The multi-dimensional intake density correction method for an EGR engine according to claim 1, characterized in that, The method for determining the weighted charging efficiency based on the intake VVT ​​angle, exhaust VVT angle, engine speed, and intake / exhaust pressure ratio includes: Based on the intake VVT ​​angle and exhaust VVT angle, determine the high reference position, low reference position, high reference position, and low reference position of the intake VVT ​​angle; Based on the high reference position of the intake VVT ​​angle, the low reference position of the intake VVT ​​angle, the high reference position of the exhaust VVT angle, the low reference position of the exhaust VVT angle, the intake and exhaust pressure ratio, and the engine speed, the first combination charging efficiency, the second combination charging efficiency, the third combination charging efficiency, and the fourth combination charging efficiency are obtained by referring to the table. Based on the intake VVT ​​angle, the high reference position of the intake VVT ​​angle, and the low reference position of the intake VVT ​​angle, determine the weighting coefficient of the high reference position of the intake VVT ​​angle and the weighting coefficient of the low reference position of the intake VVT ​​angle. Based on the exhaust VVT angle, the high reference position of the exhaust VVT angle, and the low reference position of the exhaust VVT angle, determine the weighting coefficient of the high reference position of the exhaust VVT angle and the weighting coefficient of the low reference position of the exhaust VVT angle. The weighted inflation efficiency is determined based on the inflation efficiency of the first combination, the inflation efficiency of the second combination, the inflation efficiency of the third combination, the inflation efficiency of the fourth combination, the weighting coefficient of the high reference position of the intake VVT ​​angle, the weighting coefficient of the low reference position of the intake VVT ​​angle, the weighting coefficient of the high reference position of the exhaust VVT angle, and the weighting coefficient of the low reference position of the exhaust VVT angle.

8. The multi-dimensional intake density correction method for an EGR engine according to claim 6, characterized in that, The method for determining the final charging efficiency based on engine speed, gas pressure after throttle, and weighted charging efficiency includes: Based on the engine speed and the fresh air flow rate in the cylinder in the previous calculation cycle, linear interpolation is performed to look up the table and obtain the exhaust pressure of the engine under standard operating conditions. The first pressure ratio coefficient is determined based on the exhaust pressure and the gas pressure after the throttle valve during standard engine operating conditions. The second pressure ratio coefficient is determined based on the final back pressure and the gas pressure after the throttle valve. Based on engine speed and gas pressure after throttle, look up the table to obtain the correction factor; The influence coefficient of back pressure on inflation efficiency is determined based on the correction factor, the first pressure ratio coefficient, and the second pressure ratio coefficient. Based on the correction factor and the influence coefficient of back pressure on inflation efficiency, determine the final correction value of back pressure on inflation efficiency. The final inflation efficiency is determined based on the weighted inflation efficiency and the final value of the correction for inflation efficiency by back pressure.

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 steps of the multi-dimensional intake density correction method for the EGR engine according to any one of claims 1-8.

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