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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ComponentsCalibration

ParametersResults

Compressor

Mass flow

Multiplier

Efficiency

Multiplier

Heat Exchangers – Condenser /

Evaporator

Heat Transfer

Multiplier

Friction

Multiplier

MAC Component Calibration

1 – INTRODUCTION

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ComponentsCalibration

ParametersResults

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