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SAN DEN
7/18/02
A Look At Automotive Air Conditioning Past, Present & Future
Purdue Conference 2002
Presentation by Jacob Bayyouk
Purdue Conference 2002
Air vents –In vehicle floor
Dirt & Dust –Not much cooling
Something hadTo be
Done !!!
Later, closed cabs were introduced and vehicle interior was unbearable !!
Early Automobiles
The early automobiles were not climate controlled :- Passengers bundled up in the winter- Cooling was the breeze generated from vehicle top speed ..15mph.
Purdue Conference 2002 SAN DEN
The Early Days Of Cooling
Purdue Conference 2002 SAN DEN
1930’sSwamp Coolers
Evaporative cooling system : - Blowing air over water to reduce it’s temperature
1884William Whiteley used blocks of ice:
§ Placed in a tray under horse drawn carriage § Blowing air inside the carriage by attaching
fan to the axle
Introduction Of Air Conditioning To Automotives
1939Cadillac A/C prototype.
A self contained unit in the trunk
1930First car to be Air Conditioned.
Customized Cadillac outfittedfor John Hamman Jr.
Purdue Conference 2002 SAN DEN
1939Packard was the first mass produced
car with air conditioning
Introduction Of Air Conditioning To Automotives
1941 - Cadillac introduced 300 cars with air conditioning
Compressor Installed
Under Hood
No CompressorClutch
Belt Removal Was Needed
To Turn The System
OffIn the late 40’s
A/C controls were introduced - However, Located in the rear of passenger compartment.
1957 - All Cadillac Eldorado Broughams included A/C as a standard feature.
1956 - All American car makers offerd air conditioning as an option.
1954 – 36,000 vehicles (approx.) had factory installed air conditioning.
In the 50’s the usage of HCFC-22 was discontinued And was replaced by CFC-12
Purdue Conference 2002 SAN DEN
Automotive Air Conditioning Compressors
40’s - 60’s Single (1) and dual (2) piston reciprocating compressorsLarge / Bulky / Heavy
60’s - 70’s -Swash plate / Wobble plate fixed displacement compressors Multiple pistons – 5, 6, 7 , …. 10
Smaller / Lighter/ Smoother operation
70’s - 80’s - Rotary compressors - Internally Controlled Variable Wobble plate compressors
Smaller / Lighter/ Smoother operation-Scroll compressor introduction
High speed/ Efficiency/Compact
80’s – 2000’s -Electric variable speed compressors - Advanced swash plate compressors - Externally controlled variable displacement piston compressors
( With & W/O Clutch)- New concepts are under development for Alt. Ref. ( i.e. CO2)
Purdue Conference 2002 SAN DEN
2
Automotive Air Conditioning Challenged1987
Montreal Protocol – Complete Phase out of CFC’s / Adoption of HFC-134a
The Industry Had To Move Rapidly And Adapt To New Rules / Regulations And Refrigerants
In the past things were simple
No rules / regulations
Single refrigerant And oil
Now the industryhad to deal
with multipleissues & situations
Things were nolonger the same
Recycle
Moisture Concerns
Contamination
RetrofitsRecovery
Multiple Lubricants
Multiple Ref.
The Industry Successfully Implemented The ChangeBy 1994
All New Production In USA / Europe / Japan Was With HFC-134a
Purdue Conference 2002 SAN DEN
Automotive A/C Compressors Of TodayAutomotive A/C Compressors Of Today
Fixed Displacement, Swash Plate / Rotary
Scroll CompressorElectric Scroll Compressor
Internally Controlled Variable Displacement Compressor
Externally Controlled VariableDisplacement Compressor
Purdue Conference 2002 SAN DEN
Automotive A/C Scroll Compressor Cross Section ViewAutomotive A/C Scroll Compressor Cross Section View
Purdue Conference 2002 SAN DEN
• Heat exchanger
Automotive Electric Scroll Comp. Cross Section ViewAutomotive Electric Scroll Comp. Cross Section View
Purdue Conference 2002 SAN DEN
Automotive A/C Internally Controlled VariableAutomotive A/C Internally Controlled Variable
Compressors Compressors
Internally Variable Displacement Piston Compressor Advantages
Wide range capacity control (virtually eliminates clutch cycling)
Greater reliability
Improved fuel economy
Elimination of evaporator icing
Improved vehicle driveability And quieter operation
Purdue Conference 2002 SAN DEN
PistonShoe
Swash plate
Control valve
(MFCV)
Suction chamberOrifice
Crankcase
Hinge
Clutch
Spring
Discharge pressure
Crankcase pressure
Bellows Valve
Suction chamber
Crankcase
Rod
Suction pressure
Internally Controlled Variable Displacement CompressorInternally Controlled Variable Displacement Compressor
Construction / Cross Section View Construction / Cross Section View
Purdue Conference 2002 SAN DEN
3
Discharge chamber(Pd)
Suction chamber(Ps)
Crankcase (Pc)
Orifice
Control valve (MFCV) Suction gas
Discharge gas
CompressionBlow-by gas
Crankcase pressure is regulated by opening & closing of the control valve. The control valve has bellows which senses suction pressure. Therefore, the control valve regulates crankcase pressure to maintain desirable suction pressure, which is determined by the design of the valve itself. ( A very small amount of discharge gas flows into crankcase via the orifice. The purpose is to stabilize displacement control at low heat loads.)
Internally Controlled Variable Displacement CompressorInternally Controlled Variable Displacement Compressor
Displacement Control Concept Displacement Control Concept
Purdue Conference 2002 SAN DEN
Automotive A/C Externally Controlled VariableAutomotive A/C Externally Controlled Variable
Compressors Compressors
Externally Variable Displacement Piston Compressor Advantages
Higher speed operation
Optimised displacement allowing improved engine management:-reduced fuel consumption- reduced emissions
Allows for virtually zero displacement – eliminating the clutch
Improved comfort & energy efficiency through minimization of reheat
Purdue Conference 2002 SAN DEN
Control valve
(EMPCV)
Suction chamber
Dischargechamber
Variable orificePiston
Swash plateHinge
Shoe
Torque limiter
Crankcase
Externally Controlled Variable Displacement CompressorExternally Controlled Variable Displacement Compressor
Construction / Cross Section View Construction / Cross Section View
Crankcase
Suction pressureBellows
Valve
Solenoid
Discharge gas
Plunger
Stator
Maximum Displacement Control
Purdue Conference 2002 SAN DEN
Discharge chamber(Pd)
Suction chamber(Ps)
Crankcase
Pc=Ps
Control valve
(closed)
Variable orifice
A higher control current is supplied to the control valve so that the passage from discharge chamber to crankcase is closed. The variable orifice has enough area to run blow-by gas into suction chamber. Therefore, the crankcase pressure & suction pressure tend to equalize and hence the cam angle increases to maximum.
Suction gas
Discharge gas
CompressionBlow-by gas
Externally Controlled Variable Displacement CompressorExternally Controlled Variable Displacement Compressor
Displacement Control Concept Displacement Control Concept Maximum Displacement
Purdue Conference 2002 SAN DEN
Control valve (Open)
Suction chamber
Discharge chamber
Variable orifice
Piston
Swash plateCrankcase
Externally Controlled Variable Displacement CompressorExternally Controlled Variable Displacement Compressor
Construction / Cross Section View Construction / Cross Section View
Minimum Displacement Control
Purdue Conference 2002 SAN DEN
Discharge chamber(Pd)
Suction chamber(Ps)
Crankcase
Pc>Ps
Control valve(Open)
Variable orifice Suction gas
Discharge gas
CompressionBlow-by gas
The control valve has a bellows which senses suction pressure. T he change in displacement is achieved by the bellows adjusting the flow of discharge gas to the crankcase. A change in the current to the solenoid varies the force on the plunger which in turn modifies the set point controlled by the bellows.
Externally Controlled Variable Displacement CompressorExternally Controlled Variable Displacement Compressor
Displacement Control Concept Displacement Control Concept Minimum Displacement / Control State
Purdue Conference 2002 SAN DEN
4
Automotive Air Conditioning Challenges Continues
The industry implemented HFC-134a successfully. While HFC-134a achieved :
-Zero ozone depletion potential -GWP ~ 7 times less than CFC-12
Environmental concerns remained
HFC-134a GWP = 1300
Debate to replace HFC-134a started .And
The push for Natural Refrigerants gainedMomentum
1997 KyotoThe debates culminated in the Kyoto Conference
HFC family was listed as one of the six substancesThat are most damaging to global warming.
CO2Became the leading
Candidate.
This direction was popularparticular by European
automotive industry.
CO2 Safety Concerns
The U.S. Automotive industry
favored additionalresearch to confirm
suitable alternative
The Industry Is At Another Cross Roads
Purdue Conference 2002 SAN DEN
Automotive Air Conditioning Challenges Continues
The Change From HFC-134a To CO2, What Is It ?
Evolutionary Revolutionary
CFC-12 Change To HFC-134a
Many similarities prevailed : -Pressures -Temperature - Chemically-Materials - Components
Evolutionary
HFC -134a Change To CO2
Many differences exist : - High Pressures - Higher Temperature - Chemically-New Materials - New Components -Safety
Revolutionary
Purdue Conference 2002 SAN DEN
? CO2 , DCX Germany indicated (@ 2002 Phoenix meeting) that they will introduce CO2 in their vehicles as early as 2005
? Considering: (CO2 , R-152a, other..)
- CO2 - High pressure & cost- R152a - Potential flammability issue
- Currently no specific plans
-The 1997 Kyoto Conference listed HFC family as one of the six substances that are most damaging to global warming.
- Future vehicles will need auxiliary heat source (i.e. Heat pump, ..)
? No specific preference. Endorses further R&D
Europeespecially VDA group
USA, Japan
EPA
Automotive Air Conditioning Challenges Continues
Alternative Refrigerant Future Direction !!!!!!!!!!
Purdue Conference 2002 SAN DEN
Automotive A/C Compressors Future TrendsAutomotive A/C Compressors Future Trends
Line-up of Products
Fuel Sa
ving
Enviro
nmen
tal Pro
tection
Externally Externally ControlledControlled
CompressorCompressor
Alternative Alternative RefrigerantRefrigerant
CO2
Advanced FixedAdvanced FixedDisplacementDisplacement
Internally Internally ControlledControlled
compressorcompressor
Tech
nolo
gy L
evel
Electric Electric CompressorCompressor
Hybrid compressorHybrid compressor
M
IntegratedIntegratedElectric Electric
CompressorCompressor
Purdue Conference 2002 SAN DEN
Automotive Air Conditioning Summary / Challenges
1974 Molins & Rawlins Discovery -- CFC’s Depletion of Ozone Layer
70’s Efforts To Reduce System Charge / Reduce Leaks
1987 Montreal Protocol – Complete Phase out of CFC’s / Adoption of HFC-134a
50’s HCFC-22 Usage Was Discontinued, CFC-12 Become Sole Refrigerant
1930 First Customized Vehicle With A/C Unit - Houston, Texas
1884 William Whiteley Introduced Ice Blocks / Fan As A Cooling Device
Purdue Conference 2002 SAN DEN
91 -94 All New Production Was Converted to HFC-134a; USA/ Europe/ Japan
1997Kyoto Conference Listed HFC Family As One Of The Six Substances That
Are Most Damaging To Global Warming
Automotive Air Conditioning Summary / Challenges
87 - 90 Rapid Change In The industry To Design/Introduce HFC -134a System
2002 Industry Continuing Debate On Best Replacement Refrigerant To HFC-134a
Purdue Conference 2002 SAN DEN
5
Future Refrigerant / Application Technology Projection
Purdue Conference 2002 SAN DEN
,000
Common rail
DieselDirect injectionCommon rail
Advanced type
Gasoline
Direct injection
Lean burn
Year 2010current
Diesel engine
Gasoline engine
Natural gas etc.
Fuel cell vehicle
Hybrid vehicle
Electric vehicle
42V vehicle
Future Vehicle Technology Projection
201080% (approx.) Is Expected To Be Internal Combustion Engine
Purdue Conference 2002 SAN DEN
Purdue Conference 2002 SAN DEN