涡轮增压控制技术讲义.pdf

涡轮增压发动机匹配，控制与标定技术2017-7-22 北京Airflow AlgorithmOverview, Description and Calibration空气流量，压力和温度的模型和标定Overview of Airflow Algorithm• Single algorithm for engine flow variables, based on physical models of flow: • Pressure State Estimator • engine mass flows • engine manifold pressures • Temperature State Estimator • engine gas temperatures• Provides engine flow variables and calibrations required by EMS control, diagnostic and estimation algorithms: • Fueling • Spark • Purge • EGR/VVT • Air Control (Torque-based s/w)Sec. 1.1.2Value: • Easy to understand the interaction between the sub-systems;for example:throttle flow -> filling dynamics -> port flow• Easy to add and subtract sub-systems • AIR • Systems with and without EGR valves • ETC systems without IAC• Solid base of inputs (estimation or calibrations) to more advanced algorithms • torque-based algorithms • air/EGR control • cam phasingAlgorithm DescriptionOverviewFlowEstimatesTemperatureEstimatesPressureEstimatesSensor MeasurementsActuator CommandsFlow EstimatesTemperature EstimatesPressure EstimatesFigure 3, Sec. 3.2Algorithm Description FlowsFlow Estimation ModelsValve PositionFlowInlet PressureOutlet PressureInlet TemperatureFlow = F(Inlet Pressure, Inlet Temperature, valve position) * F(pressure ratio)Outlet Pressure Inlet Pressure00 .10 .20 .30 .40 .50 .60 .70 .80 .9100 .20 .40 .60 .811 .21 .401 02 03 04 05 06 07 08 09 01 0 0024681 01 21 41 6*Pressure RatioValve Position0.20.40.60.81050100150200051015P re s s ure R a tioVa lve P os itionStandard Flow [g/s]ORPressure RatioValve PositionFlowSonic Flow2 x 2D3DSec. 3.2.1.12D Valve Flow Estimation Models Implemented for:Throttle ValveEGR ValveIdle Air ValveDensity CorrectionfromStandard Conditions*Valve Mass Flow under Standard ConditionsValve Mass Flow Estimate/Valve Position (if variable)Valve Inlet PressureValve Outlet PressureValve Inlet TemperatureValve Pressure Ratio Valve Sonic Flow Cal Table*0102030405060708090100050100150200250Va lve P os itionSonic Standard Flow [g/s]00.10.20.30.40.50.60.70.80.9100.20.40.60.811.21.4Pressure Ratio Effect TableValve PositionSonic FlowPressure RatioHard-Coded Pressure Ratio EffectCal TableSec. 3.2.1.13D Flow Estimation ModelStandardFlowCalculationDensity CorrectionfromStandard Conditions*Valve Mass Flow under Standard ConditionsValve Mass Flow Estimate/Valve PositionValve Inlet PressureValve Outlet PressureValve Inlet TemperatureValve Pressure Ratio0.20.40.60.81050100150200051015P re s s ure R a tioVa lve P os itionStandard Flow [g/s]Purge Flow – Line restrictions force 3D representation – Flow through vent valve; or – Flow through tank with low tank-to-can restrictionPurge-From-Tank Flow – Compile time option to include – Special case for ORVR systems with high tank-to-can restrictionValve PositionPressure RatioFlowSec. 3.2.1.1Intake Port (Engine) Airflow• Speed-Density Relationship (Page 25)• Volumetric Efficiency is a function of • RPM • Engine Pressure Ratio •Backpressure/MAPFigure 7, Sec. 3.2.1.3024681 005 0001 0 00 00 .40 .50 .60 .70 .80 .911 .1E n gin e P re s s u re [-]Volum etric E ffic ie n c y C a libr atio n Ta b leE n g in e S p e ed [R P M ]VE [-]Pressure RatioVERPMAlgorithm Description PressuresPressure Estimation Model• Based on Pressure-Volume-Temperature relationship for a manifold• Differentiate to generate Pressure Estimation Model• Integrate Pressure Slope, , to estimate new pressure.UpdateManifold PressureEstimateCalculateNet ManifoldFlowTemperature EstimatesFlow Estimates Pressure EstimateFigure 8, Sec. 3.2.2.1mRTPV net_flowmVRTPPnet_flowm Robustness• Intake Manifold Pressure (MAP) Estimate • Compared to MAP measurement • Difference (measured-estimated) used as feedback to airflow model• Proportional Correction • Based on difference• Integral Correction • Based on integral of difference. • Used to remove bias errors.Plant ModelPlant Model+-Measured StatesError VectorMeasured StatesPlantPlant InputsState EstimatorUnmeasured StatesLEstimatesFigure 9, Sec. 3.2.2.1Robustness • Integral Correction (IC) Term • Integrates to a value necessary to cancel out steady-state differences in the net flow calculation. • Primarily, differences between the VE and Throttle tables. • Storing (learning) of IC value as a function of operating point (TPS).• Calibration • Number of RAM cells (1-17), generally calibrate to 17. • Maximum TPS of RAM cells, generally calibrate to ~45%. • For example: If max_tps = 40% and #_cells=17, then there are 17 RAM cells between 0 and 40% TPS. • 2D bound table, a function of flow (physically defined, no calibration needed.)Sec. 3.2.2.3Barometric Pressure Estimateintakem MAPTPSIATBaroIntake_Flow = F(Baro, IAT, TPS, IAC) * F(pressure ratio)MAP BaroBaro= MAP * F(Intake_Flow, MAP, IAT, TPS, IAC)Baro= MAP * CAL(Normalized_Intake_Flow, Normalized_Effective_Area)Intake SystemSec. 3.2.2.20 0.2 0.4 0.6 0.8 100.20.40.60.8111.522.533.54Norm Intake Flow [-]Barometric Pressure CalibrationNorm Eff Area [-]P。