MODELING ELECTRIFIED VEHICLES UNDER DIFFERENT THERMAL CONDITIONS Namwook Kim, Neeraj Shidore, Dominik Karbowski, Aymeric Rousseau Argonne National Laboratory
Electrical consumption (wh/milie) Temperature Has a Significant Impact on the Energy Consumption of Electrified Vehicles Data on the Urban drive Cycle from Argonne s Advanced Powertrain Research Facility.5 +92% PHEV (CS mode) +59%.5 +74% HEV +59%.3 %.3 %.1.1 5 4 3 2-7ºC 21ºC 35ºC -7ºC 21ºC 35ºC EREV (CD mode) +94% + a% +41% % 1-7ºC 21ºC 35ºC 2
Radiator Entire Vehicle Models (incl. Thermal) Were Developed From Results Dyno test data from APRF (Argonne) Control and Performance Analysis 12 engine operation target Engine torque (Nm) 1 8 6 4 ºC -7 21 35 Heat capacity estimation data vehicle speed (m/s) engine speed (rad/s) engine torque (Nm) 3 2 1-1 55 2 4 6 8 1 12 4 3 2 1 15 1 5 UDDS 2 4 6 8 1 124 Model -5 2 4 6 8 1 12 time Validation (s) Simulation data Model Development (Autonomie) fuel consumption (kg) SOC (%) temperature (C).3.1 2 4 6 8 1 12 7 Simu 65 6 Simu component Tamb Fan UDDS 5 2 4 6 8 1 12 8 6 Engine() Engine(Simu) Battery() Battery(Simu) 2 4 6 8 1 12 Simu time (s) Teng_room coolant loop Engine heatercore loop Teng Valve Simu Simu Heatercore 2 5 1 15 2 25 3 35 4 45 Engine speed (rad/s) Driver power demand SOC Mode decision (Engine on/off) Engine on/off demand Engine on/off demand Thermal conditions Energy Engine management power demand (SOC balancing) Engine torque demand Engine target Engine Motor 2 generating speed demand Motor 2: torque demand Engine speed tracking Engine torque demand Motor 2 torque demand mode behaviors controller Battery power demand Driver power demand Motor: torque target generation Motor torque demand 3
Validation Completed for Multiple Powertrains Conventional Vehicle Ford Fusion Extended Range Electric Vehicles (E-REV) GM Volt Hybrid Electric Vehicles (HEV) Toyota Prius Hybrid Battery Electric Vehicles (BEV) Ford Focus BEV Plug-In HEVs (PHEV) Toyota Prius Plug-in Hybrid Conventional HEV & PHEV Toyota Prius Ford Fusion E-REV Electric Vehicle Ford Focus BEV GM VOLT 4
Component Validation
Radiator Component Thermal Models Engine Thermal Model m eng C eng T eng = Q fuel P work Q exhaust Q coolant Q air Q heating Q fuel = H l m fuel P work = S eng T eng Q exhaust = m eg C eg T eg Q air = αa T eng T eng_room Q heating = f heating (T cabin ) T env Fan T eng_room Q fuel : Heat generated by fuel P work : Power converted to mechanical power Q exhaust : Heat exhausted by exhaust gas Q coolant : Heat rejected by coolant Q air : Heat transfer to engine room Q heating : Heat given to cabin (cold only) Q coolant Qcoolant = fcooling(teng) fuel Engine Valve exhausted gas Q fuel T eng Heatercore P mech T eng Q heating Q air Q exhausted Engine, battery, cabin, wheel, motor, and gearbox models have been developed
Component Efficiency Depends on Temperature Engine Fuel Efficiency 15 Wheel torque loss Wheel torque loss (Nm) 1 5.795x 2-1.12x 1 + 67.1-5 -5 5 1 15 2 25 3 35 4 45 5 Tire temperature (C) Battery Internal Resistance
Electric Energy Consumption of the Climate Control System PHEV BEV Heating Heating Cooling Cooling Engine waste heat is provided for HEV if the engine is turned on.
Component Model Validation (e.g. Climate Control System) Temperature (C) 5 4 3 2 1 PHEV Cabin Temperature and AC Operation Cabin Temperature () Cabin Temperature (Simulation) Cabin Inlet Temperature () Cabin Inlet Temperature (Simulation) Temperature (C) 3 25 2 15 1 5 Cabin Temperature and Heater Operation Cabin Temperature () Cabin Temperature (Simulation) 2 4 6 8 1 12 2 4 6 8 1 12 AC Power (kw) 5 4 3 2 1 AC Power () AC Power (Simulation) Heater Power (kw) 1 8 6 4 2 Heater Power () Heater Power (Simulation) 2 4 6 8 1 12 Time (s) 2 4 6 8 1 12 Time (s) At the component level, thermal models are validated with test data.
Vehicle Control
Cooler Engine Leads to Engine Being ON for Warm-Up Prius HEV Engine is turned ON if the coolant temperature is low (a) 25 Vehicle speed (m/s) [x 1] Engine speed (rad/s) Engine torque (N.m) Coolant temperature (C) 7 The engine is not turned OFF if the coolant temperature is low. (b) 25 Not turned off 7 2 65 2 65 Speed, Torque 15 1 Turned on 6 55 15 1 6 55 Temperature (C) 5 5 5 5 45 45 95 1 15 11 Time (s) 3 35 4 45 Time (s)
Engine Control Is Significantly Affected by Temperature Conditions Prius HEV Cold engine: warm-up and idling In between: produces torque, but left on at low power Coolant temperature (C) (C) Engine speed speed (rad/s) (rad/s) Engine torque torque (Nm) (Nm) 15 15 1 1 5 5 2 4 6 8 1 12 25 2 4 6Time (s) 8 1 12 25 2 2 15 15 1 1 5 5 2 4 6 8 1 12 15 2 4 6 8 1 12 15 1 1 Coolant temperature (hot) Coolant temperature (medium) (hot) Coolant temperature (cold) (medium) Coolant temperature (cold) 5 5-5 -5 2 4 6 8 1 12 2 4 Time 6 (s) 8 1 12 Time (s) 25 25 2 2 15 15 1 1 5 5-5 -5 Vehicle speed speed (m/s) (m/s) Hot Conditions: Engine has many ON/OFF, High Torque when ON
Engine May also Starts to Warm-up the Cabin (no Electrical Heater) Prius HEV 9 Heater off Heater on 8 7 Engine coolant temp (C) 6 5 4 3 2 Waste heat provided for the cabin 1 2 4 6 8 1 12 14 Time (s)
For the Prius PHEV too, Engine Is Used for Cabin Heating Prius PHEV under -7C ambient temperature Vehicle Speed (m/s) 3 2 1 Speed, Torque, Temperature and Power 35 3 25 2 15 1 5 2 4 6 8 1 12 14 Engine torque (N.m) Engine speed (rad/s) Engine coolant temperature (C) Engine turn off points Engine turn on points -5 2 4 6 8 1 12 14 2 Time (s) 1 8 6 4 Engine coolant temp (C)
Vehicle Validation and Analysis
Vehicle Level Control Validation Vehicle speed (m/s) Engine speed (rad/s) Engine torque (Nm) 3 2 1 4 3 2 1 12 1 2 4 6 8 1 12 2 4 6 8 1 12 8 6 4 2 HEV 2 4 6 8 1 12 time (s) Simu Simu Simu SOC (%) Engine temperature (C).5.3.1 2 4 6 8 1 12 6 55 5 Simu Simu 45 2 4 6 8 1 12 1 Simu 9 8 7 2 4 6 8 1 12 time (s) Vehicle level control is validated with test data, such as engine On/Off, SOC balancing, and operating torque.
Models Are Validated within to Uncertainty Under Different Ambient Temperature 1 Conv. Simulation.8.7 HEV Simulation.8.5.3.1-7 C 7ºC 21ºC 22 C 35ºC35 C -7 C 7ºC 21ºC 22 C 35ºC35 C.8.7 PHEV (CS) Simulation.8.7 EREV (CS) Simulation.5.5.3.3.1.1 7ºC 21ºC 35ºC 7ºC 21ºC 35ºC -7 C 22 C 35 C -7 C 22 C 35 C 17
Electrical consumption (kwh) Models Are Validated within to Uncertainty Under Different Ambient Temperature 1 Conv. Simulation.8.7 HEV Simulation.8.5.3.1-7 C 7ºC 21ºC 22 C 35ºC35 C -7 C 7ºC 21ºC 22 C 35ºC35 C.8.7 PHEV (CS) Simulation 5 4 EV Simulation.5 3.3 2.1 1 7ºC 21ºC 35ºC 7ºC 21ºC 35ºC -7 C 22 C 35 C -7 C 22 C 35 C 18
Thermal Impact On Energy Consumption Is Analyzed Based on Simulation Models (Conv. & HEV) Conv. HEV Cabin is sized, so that all vehicles have the similar hvac power consumption Cold Start Hot Start 1.2 Cold Start Hot Start 1.2 1 1.8 Cold Start initial condition all initial temperatures of components are the same as the ambient temperature.8 Hot Start initial condition Engine and coolant temp. (9C) Cabin temp. (22C) Transmission and oil temp. (6C) Initial condition is the same as the Conv. Hot Start initial condition Battery temp. (3C) -2-1 1 2 3 4 Ambient temperature (C) -2-1 1 2 3 4 Ambient temperature (C) 19
Thermal Impact On Energy Consumption Is Analyzed Based on Simulation Models (PHEV & EV) PHEV EV Electrical consumption (kwh) 1.2 1.8-2 -1 1 2 3 4 Ambient temperature (C) 2 1.5 1 The same initial condition as HEV Engine should be turned on for heating the cabin. There is a drastic change of the pattern by the engine on threshold for Cold Start.5 Cold Start Hot Start -2-1 1 2 3 4 Ambient temperature (C) Cold Start Hot Start Electrical consumption (kwh) 7 6 5 4 3 2 1 Cold Start Hot Start Cold Start initial condition the same as the ambient temp. Not cold when ambient temp > 3C Hot Start initial condition Battery temperature (3C) Cabin temperature (22C) -2-1 1 2 3 4 Ambient temperature (C) 2
Drive Cycles: HWFET 6 5 4 3 2 1 2 4 6 8 1 12 14 16 Drive Cycles: UDDS User: nakim Time Copyright Program 1. 6 5 4 3 2 1 Date: 18-Apr-214 Date: 18-Apr-214 2 4 6 8 1 12 14 Drive Cycles: US6 User: nakim Time Copyright Program 1.Date: 18-Apr-214 Drive Cycles: SC3 9 8 7 6 5 4 3 2 1 sch c ycle sch c ycle 1 2 3 4 5 6 User: nakim Time 1 2 3 4 5 6 Copyright Program 1. User: nakim Time Copyright Program 1. 6 5 4 3 2 1 sch c ycle Date: 18-Apr-214 Real-World Scenario with Thermal Impact Cycle synthesizing 15 Distribution of Vehicle Mass(Conventional Vehicle (Automatic)) Real World Driving Cycles Number of appearance 1 5 ASSUMPTIONS from multi-resources Temp. Conditions 142 144 146 148 15 152 154 156 158 Vehicle Mass(kg) Conv. PHEV E-REV AUTONOMIE on high performance computing HEV EV Comparative studies ANALYSIS by database tool Energy distribution 21
Summary Electrified vehicles are more affected by ambient temperature than conventional vehicles. Models of entire xevs were built in Autonomie and validated using data from chassis dynamometer with thermal chamber Models can be used for: More accurate energy consumption prediction Control optimization Future work: Control optimization with thermal impacts Estimation of energy consumption in a real-world scenario 22