Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

1

CLIMATECONTROL

ENGINECOOLING

Condenser

PC

PW

PF

Expansion valve

Evaporator

GMV

Compressor

Receiver drier

Pressure switch

Condensor High pressure

Low pressure

AC LOOP OVERVIEW

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

2

CLIMATECONTROL

ENGINECOOLING

AC LOOP OVERVIEW

Compressor

Bottle

Condenser

HVAC unit

Control panel

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

3

CLIMATECONTROL

ENGINECOOLING

PW

(3) Compressor

(1) Expansion valve

Fluid Pressure & Temperature

70°C20 bars

0°C3 bars

High P, T°

(4) Condenser

PC

T° ext

PE

Low P, T°(2) Evaporator

T° habitacle

AC LOOP PRINCIPLE (2/3)

Stored energy in the fluid

GAS STATELIQUID STATE

Energy balance : PE + PW = PC

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

4

CLIMATECONTROL

ENGINECOOLING

AC LOOP CYCLE ON DIAGRAM OF MOLLIER

50.0

10.0

5.0

1.0

0.5

0.1

100 200 300 400 500

65°

0° 100°

0.2 0.4 0.6 0.8-60°

-40°

-20

20

40°60°

Pressurebar

Enthalpy kJ/kg

COMPRESSION

CONDENSATION

EVAPORATION

De-overheatSub-cooling

Superheat0°

0°60°

DETENT

Liquid + Vapour

Vapour

Saturated liquid

Saturated vapour

Liquid

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

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CLIMATECONTROL

ENGINECOOLING

AC LOOP WITH AN EXPANSION VALVE

EVAPORATOR

COMPRESSOR

CONDENSER

RECEIVER DRIEREXPANSION

VALVE

Temperature sensor

G.M.V.

19 bars60°C

3 bars-1°C

3 bars3°C

3 bars5°C

20 bars110°C

19 bars 60°C4 bars

16°C

PRESSURESWITCH

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

6

CLIMATECONTROL

ENGINECOOLING

AC LOOP WITH AN ORIFICE

EVAPORATOR

COMPRESSOR

CONDENSER

ACCUMULATOR

ORIFICETUBE

Temperature sensor

PRESSURESWITCH

G.M.V

3 bars3°C

5 bars16°C

3 bars-1°C

19 bars60°C

19 bars60°C

20 bars110°C

3 bars5°C

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

7

CLIMATECONTROL

ENGINECOOLING

Serpentin technology Mechanical assembly Brazed tubes

Initial technology Medium performances High increasing

Low performance :it disapears

Available technologyfor vehicle with large

front surfaceHigh performances

Low cost

THE CONDENSER : TECHNOLOGIES

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

8

CLIMATECONTROL

ENGINECOOLING

THE EXPANSION VALVE (TXV)

It is between the drier receiver and the evaporator,

linked to the evaporator

EXPANSION VALVE (TXV) - MAIN FUNCTIONS Sudden pressure drop: High to low pressure Control the refrigerant cooling Control of the superheat by controling the

mass flow EXPANSION VALVE (TXV) - CRITERIAS OF CHOICE

Performance max in the car Freezing of the evaporator Superheat level Stability of the system

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

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CLIMATECONTROL

ENGINECOOLING

THE ORIFICE TUBE

ORIFICE TUBE - MAIN FUNCTIONS

IDEM TXV BUT NO CONTROL OF SUPERHEAT & MASS FLOW

Orifice Tube

Air outlet temperature (power)

Sub-cooling

Superheat outlet evaporator

Pressure and temperature outlet compressor

It is always at the evaporator inlet

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

10

CLIMATECONTROL

ENGINECOOLING

THE EVAPORATOR

Between expension device and the compressor.

In the vehicle, it is in the HVAC unit, under the cockpit.

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

11

CLIMATECONTROL

ENGINECOOLING

THE EVAPORATOR : FUNCTIONS

To supply the required cooling power for the car cabin

The required thermal power is defined during the theorical sizing of the A/C loop components. It depends on the thermal balance of the car cabine and on customer’s specification

The evaporator is selected in the Valeo range to fit the thermal performance together with de contraintes :

economical constraints

car integration & environment constraints

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

12

CLIMATECONTROL

ENGINECOOLING

It is between the condenser and the expansion valve (TXV)

in the engine compartment

THE DRIER RECEIVER

FUNCTION 1 :

To supply the expansion valve with liquid refrigerant

To constitute a liquid reserve

FUNCTION 2 : Dehumidification of the circulating fluid

FUNCTION 3 : To filter solid impurities

SOLUTIONS :

Glass fibre disks with a hole for the diver tube

Or thermoformed bags containing the desiccant and the filter, in an annulus

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

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CLIMATECONTROL

ENGINECOOLING

THE ACCUMULATOR

Accumulator functions:

To supply the compressor with entirely gaseous refrigerant

To dehumidify and filter the refrigerant / oil mixture

To ensure that the oil returns to the compressor

Principal characteristics of an accumulator :

system used to separate liquid / vapour

useful volume

desiccant mass

position of the oil return hole

It is between the evaporator and the compressor in the engine

compartment

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

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CLIMATECONTROL

ENGINECOOLING

TUBES & HOSES

They link the different components to make the refrigerant circulating

in the AC loop

Tubes & Hoses Functions

To transport R134a and limit leaks

To resist to ambience and To R143A

R134a pressure & temperature

Ambience temperature and humidity & fluid bonnet

To reduce noise and vibration transmission

Not to reduce the A/C Loop performances

to reduce pressure drop / insulate (LP line f.g.)

Easy to mount on the vehicle (sensors & charge connection)

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

15

CLIMATECONTROL

ENGINECOOLING

五 点 最 合 理 的 反 映

1 〕测量：至少每 30000 公里检测风量， 确认过滤网是否脏污过度2 〕查找：先查找泄漏点， 后补加 R134a

3 〕确认：确认补加的润滑油， O 型圈（ EPDM 〕，是指定的产品，确保相融性

4 〕精确：制冷剂、润滑油的加注量，多少都不利5 〕更换：最好每次检修、每两年更换储液罐

Version APRIL 2001 ACLOOP3 - ACLOOP PEFORMANCES ANALYSIS

16

CLIMATECONTROL

ENGINECOOLING

汽车文化

宣传正确的使用习惯

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