R744 MAC Systems from conventional driven vehicles to EVs

R744 MAC Systems from conventional driven vehicles to EVs

October 2009

Confidential

© All rights with Obrist Engineering GmbH also in the event of the grant of a patent. Right of disposal like copying and distribution with us.

Content

Natural Refrigerant R744 (CO2) for MAC

System Experience

Phase 1: Functionality R744 AC & Heating System

Phase 2: Performance AC & Heating Systems

Phase 3: Controllability AC

Phase 4: Driveability & Cost for Small Vehicles AC

Phase 5: COP System Optimisation AC

Phase 6: Durability Tests AC Systems

E-Vehicles, Hybrid electrical Vehicles and PHEV

Confidential


No ozone depletion; ODP = 0

Lowest possible GWP of 1

Classified under the American Standard Heating and Refrigeration (ASHRAE) as A1

Non toxic and non flammable

R744 is one of the best known and understood substances in term of scientific research and applications.

Humans inhale and exhale it

Mankind puts it in soda and drinks it

It is a natural substance of the atmosphere

Highest efficiency, lowest indirect emissions and best LCCP vs. all others

Lowest total cost of ownership

Why Natural Refrigerant R744 (CO2)

Confidential


Single AC & HP

AC only

Dual AC & HP

System Experience

OE has build up more than 50 prototype vehicles with R744 – Systems

Future development trends towards Electrical Vehicles with A/C and HP HEV and PHEV with A/C and HP Battery cooling Thermal management

Confidential


OE System Experience

1997 2000 2004 2009

R744 Function

System Control

Small Vehicle

COP

System Durability Testing

AC & Heating Systems

AC Systems Only

Performance

Confidential


Phase 1: Functionality R744 AC & HS (1997-1999)

First development steps with R744: Demonstrate that R744 operates as refrigerant under all climate conditions Show the functionality of

- Single AC-System- Coolantside Heat Pump System- Air Side Heat Pump System- Hot Gas Cycle System

Therefore several cars were equipped with R744- Systems …

… Audi … Daimler … BMW

Confidential


HVAC

Eva

po

rato

r

Gas

coo

ler

Compressor

Accu

Air Air

IHX

HPValve

LPValve

P/T

EXV

Heating Mode:

System Description: Air Heat Pump System

Phase 1: Functionality R744 AC & HS (1997-1999)

Confidential


Phase 2: Performance AC & HS (2000-2004)

Optimisation of the Cooling- and Heating Performance in R744 Systems

Vehicle model build up

Confidential


AC Pull Down Results R744 vs. R134a (Full Size Truck)

Pull Down Head Temperature R744 vs R134a Tamb=38°C; RH=40%; SL=1000W/m2;

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90 100 110 120 130

Time [min]

Ave

rage

Hea

d Te

mp

[°C]

T_Breath_aver_R744 [°C] T_Breath_aver_R134a [°C]

Comfort Temperature 22°C

50 kph REC

80 kph REC

50 kph OSA

80 kph OSA

IDLE REC

110 kph OSA

18 min

10 K


Confidential


Heat Up Result Hot Gas System

R744 Hot Gas Cycle Coolant & Fuel Fired Heater Coolant

-20

-10

0

10

20

30

40

50

0 5 10 15 20 25 30 35 40 45Time [min]

Hea

d T

emp

[°C

]

Comfort Temp. 22°C14 min 21 min

28 min

- R744 HG Cycle- Coolant & FFH- Coolant

Cabin Head TemperatureAmbient temperature = -10°C


Confidential


Time [ min ]

Pressure

80

60

40

20

Tunnel In

Tunnel Out

Speed variation

Blower variation

Pre

ss

ure

[ b

ar

]

Phase 3: Controllability AC (2002-2008)

Targets:- Same or better controllability as R134a systems- Safe handling of the high system dynamic- Noise and torque optimised controlling

Confidential


Time [ min ]

9 °C

12 °C

6 °C

3 °C

9 °C

6 °C

3 °C

System conditions:

Cycle: Forced Idle

n_engine: 2000 rpm

Blower: 7

T_Evap: Variable

Compr.: Variable

- Stable outlet temperature within the control range of 3°C – 12 °C

Evaporator Temperature Setpoint Variation

Phase 3: Controllability AC (2002-2008)

Confidential


Phase 4: Driveability & Cost for Small Cars (2004-2006)

Vehicle Build Up for Different OEMs

Small compressors, optimized heat exchangers and control strategy have been applied to show the AC functionality in small cars with low torque engines

Confidential


Md [%]

t [-]

MEng

35/120 bar

1000 2000 3000 4000 5000 6000

Engine torque

MCom

Pcomp [%]

t [-]

Pmax

35/120 bar

1000 2000 3000 4000 5000 6000

PIdle

Compressor torque

Max. Cooling power point

Compressor torque

Controlling Strategy

Phase 4: Driveability & Cost Small Cars (2004-2006)

~~MCom

Md [%]

Adjustable max torque timing

Available engine torque

Confidential


Solution: Small Car Low Cost AC-Systems Small size fixed or variable displacement compressor Application adapted and optimized control strategy Coaxial IHX as part of lineset MCP Evaporator and Gascooler Full Flexible Tubing System PXV-System

Result: Perfect drivability for small cars with R744 AC-Systems

Phase 4: Driveability & Cost Small Cars (2004-2006)

Confidential


Phase 5: COP System Optimisation AC (2007-2009)

Phase 5 was motivated to further improve COP and reduce fuel consumption of R744 AC systems

The development phases 1 to 4 were focused on functionality and performance of R744 Systems

Confidential


Vehicle Test Results – Fuel Consumption

NEDC Fuel Consumption Test R134a vs. R744VW Touran TDI 1,9l; Tambient =20/28/35degC

Additional Fuel Consumption R134a Additional Fuel Cons. R744

T ambient

Ad

dit

ion

al

Fu

el

Co

ns

um

pti

on

l/1

00

km

Confidential


Phase 6: Durability Tests AC Systems (1999-2009)

OE has built up several vehicles with different R744 systems for durability testing at Obrist and Costumers

Obrist Engineering Vehicles (AC and Heating Systems)

Audi A4 1.6lSingle AC-SystemBuild up: 1999Mileage: ~113.000 kmMore then 10 years of city cycle operation !!

Ford Galaxy 1,9TDIAC & HG System and MCPBuild up: 2003Mileage: ~115.000 kmR&D vehicle

Confidential


Kia Sportage 1,9 TDISingle AC-SystemBuild up: 2007100.000 km Durability Test in Dubai

VW Lupo 1,0Single AC-SystemBuild up: 2004Accelerated Lifetime test 40.000 km

OE has built up several vehicles with different R744 systems for durability testing at Obrist and Costumers

Costumer Vehicles (AC Systems)

Phase 6: Durability Tests AC Systems (1999-2009)

Confidential


EVs, HEVs and PHEVs

EVs, HEVs and PHEVs have additional needs for cooling and heating compared to conventional vehiclesCabin heating and coolingBattery cooling

Efficiency in cooling and heating becomes key, since

any energy required for heating and/or cooling needs

has to be drawn from the batteryHigh battery cost Range reduction issue

Confidential


EV Heating System Consequences

Electrical Heating R744 HP

NEDC wheel average 3kW 3kW

Heating requirement 6kW 1,5kW

NEDC theo. range 90km 90km

20degC real range 60km 60km

-20degC real range 20km 45km

Vehicle becomes useless

Confidential


Example: Air Side Heat Pump for EV

High Efficient E-Compressor

Confidential


CartridgeAC - System

Battery Box

Li-Ion Battery Cooling System Development

Coolant to Refrigerant to Air

Confidential


R744 Development for conventional driven vehicles completed R744 Development for Evs, HEVs and PHEV under way

R744 is the future refrigerant since it is the only refrigerant fullfilling all the requirements for MACs and battery cooling systems

ODP and GWP

COP and Efficiency

Cost

HP capability

Summary

Documents

R744 MAC Systems from conventional driven vehicles to EVs