Performance Prediction of Automotive Air Conditioning System for Different Driving Cycle Conditions

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CAE-2| System Simulation GT-SUITE User Conference | Dec 07, 2015
Performance Prediction of Automotive Air 
Conditioning System for Different Driving 
Cycle Conditions 
Rangarajan Sa, Yamamuro Tsuyoshib, SasiKumar Ma, Kubo Masaakib, Anand Ga
aRenault Nissan Technology and Business Centre India Pvt. Ltd., Chennai, India
bNISSAN MOTOR CO., Ltd., 560-2 Okatsukoku, Atsugi, Kanagawa, Japan
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Outcome of the seminar
1. Calibration of Mobile AC Components 
2. Types of Compressor and its control logics 
3. Performance of AC system for different driving cycle
4. Fuel consumption study with AC - ON/OFF
5. Conclusion
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CONTENTSContents
1. Introduction
2. Performance of AC system
3. Conclusion
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About the Company - RNTBCI
Renault Nissan Technology & Business Centre India Pvt. Ltd. is a
joint venture, established under the Renault Nissan Alliance on 21st
September, 2007. We cater to the localization needs of Renault and
Nissan in various research, business and automotive technologies
such as Advanced Research and Development, Advanced CAE
(Computer-Aided Engineering), Product Development, Digital Vehicle
Development and Information Systems Development. We are a
captive centre, that also has an in-house Software development
centre and Purchase – Global purchasing organization. Currently, we
have a workforce of 5000+ employees.
 R & AE
 Vehicle & P/Train 
 Global Engineering Support
 Process Engineering
 Cost Estimation
 IS/IT
 Purchasing
 BPO
 Shared Service Center
BusinessTechnology
1 – INTRODUCTION
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Physical Layout Simulation Layout
Deliverables
Scope
Image courtesy to rowleystires.com
1 – INTRODUCTION
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Fixed Displacement Compressor
Variable Displacement Compressor
Variable Speed Electric Compressor
Evolution of AC Compressor
Image courtesy to Delphi
Image courtesy to Denso
Image courtesy to Sanden
Image courtesy to Prideautocare.com
1 – INTRODUCTION
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Simulation Steps
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Calibration of MAC Components
• Condenser
• Evaporator
• Compressor
• Thermal Expansion Valve
System Integration 
• Condenser
• Evaporator
• Compressor
• Thermal Expansion Valve
Control Strategy
• Compressor control logic
• Duty Calculation – PI Controller
Driving Cycle
• Cool Down
• 5Cycle
• LA4
Component
• Heat Exchanger – Nusselt Correlation fit
• Compressor – Performance Map data
• TXV – 4 Quadrant Chart
System 
Level
• Charge quantity optimization
• Blower and Condenser air flow rate
• Compressor Speed and Initial temperatures
Control 
Logic
• Tdevapair Vs Clutch engagement – FDC
• Ps Vs % duty (Displacement) – VDC
• Tdevapair Vs % duty (Ncompressor) – VSEC
Validation
• Evaporator & Condenser air outlet temperature
• Cabin Temperature
• Compressor torque
• Fuel Consumption
1 – INTRODUCTION
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Components
Calibration 
Parameters
Results
Compressor
 Mass flow 
Multiplier
 Efficiency 
Multiplier
Heat Exchangers – Condenser / 
Evaporator
 Heat Transfer 
Multiplier
 Friction 
Multiplier
MAC Component Calibration
1 – INTRODUCTION
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Components
Calibration 
Parameters
Results
TXV
 TXV time 
constant 
Cabin
 Cabin Lumped 
Mass
 Internal HTC
1st Quadrant
Temp (K)
Pressure 
(bar)
273.15 2.3
283.15 3.6
293.15 4.7
303.15 5.9
313.15 7
2nd Quadrant
Pressure 
(bar)
Lift (mm)
0.63 0.75
2.5 0
3rd Quadrant
Lift (mm)
Mass Flow
Rate (kg/s)
0 0.014
0.2 0.042
0.6 0.066
0.75 0.07
Source: Data from 
GT-TXV tutorial model
MAC Component Calibration
1 – INTRODUCTION
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CONTENTSContents
1. Introduction
2. Performance of AC system
3. Conclusion
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Objective
 A/C Cycle performance for Fixed Displacement Compressor (FDC)
Inputs Results
 Hot Environment [Temp (ºC) & R.H (%)]
 COMP –ON/OFF based on Tdevapair
 Vehicle Speed - V1, V2 and Idling
AC Performance - Fixed Displacement Compressor 
Challenges
 AC Pipes ( suction side) heat pick-up (thermal inertia loss) has impact on evaporator air outlet 
temperature.
2 – PERFORMANCE OF AC SYSTEM
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Objective
 A/C Cycle performance with Variable Displacement Compressor (VDC). 
 Effect of fuel consumption on Fixed and Variable displacement compressor.
Results
Challenges
 Modeling of VDC using PI Control logic and validation of compressor displacement.
AC Performance - Variable Displacement Compressor 
2 – PERFORMANCE OF AC SYSTEM
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Fuel Consumption Study
Fuel Consumption Study Comparison between FDC & VDC
Outcome
 Torque on VDC is Lower than FDC. 
 Effect of fuel consumption on VDC Lower than FDC.
 Fuel economy for VDC higher than the FDC.
2 – PERFORMANCE OF AC SYSTEM
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Objective
 To predict HEV A/C Cycle performance for a Fixed displacement type Variable Speed 
Electric Compressor (VSEC) model driven by inverter.
Results
Challenges
 Modeling of VSEC using PI Control logic and modeling of “thermocouple object – Lag
response” for evaporator air outlet temperature.
AC Performance - Variable Speed Electric Compressor 
2 – PERFORMANCE OF AC SYSTEM
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Contents
1. Introduction
2. Performance of AC system
3. Conclusion
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 Simulation results of AC Cycle performance are were well correlated with test data
 Fuel consumption was found to be less in VDC comparison with FDC.
 Using system simulation we can reduce number of prototype testing and its cost 
avoidance
Challenges
 Detail geometry inputs required for Heat exchangers & Cabin.
 Performance map data – TXV & Compressor.
 Heat Pick-up (thermal inertia loss) on AC Cycle pipes.
Conclusion
3 – CONCLUSION
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Thank You