e46 solarsensor

8/19/2019 E46 SolarSensor

1/12

Initial Print D ate: 023/2000 R evision D ate: 3/17/00

Subject Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Solar R adiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Solar Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

C om ponents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

System O peration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

C ontrol C urves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

B low er Intervention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Tem perature Intervention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Ventilation Intervention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

D iagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

R em oval H ints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11

Table of Contents


2/12

2SolarSensor/ST039/3/17/00

IHKA SYSTEMS - SOLAR SENSORE38 IHKA - March 1999 (2000 M/Y)E46 IHKA - 2000 Model Year

E39 IHKA - 2001 Model Year

OBJ ECTIVES

Purpose of the System :

The purpose of the solar sensor is to com pensate the clim ate control system ’s output for

the radiant heating effect of the sun. This w ill aid the IH K A in m aintaining a constant com -

fort level, in the vehicle’s interior, during all driving conditions.

The function of heating and air conditioning system s in B M W vehicles is to provide the dri-

ver and passengers a com fortable atm osphere regardless of conditions outside of the vehi-

cle. B ased on the tem perature signal inputs, blow er setting, flaps portioning, program set-

tings in the control m odule and influencing variables, the IH KA control m odule is able to

process these inputs to achieve the desired com fort level.

The follow ing input variables are

processed by the IH K A m odule:

•Interior tem perature

•H eat exchanger tem perature

•Ventilation tem perature (E38)

•Evaporator tem perature

•Air volum e setting

•Engine tem perature and R PM

•Exterior tem perature

The processed variable “Y - factor”is determ ined by using the above inputs. The Y - fac-

tor then represents how m uch adjustm ent is necessary by the IH KA m odule to achieve the

set tem perature.

After studying this handout, you w ill be able to:

•D escribe the operation of the solar sensor as it applies to the IH KA system s.

•List the output functions effected by the solar sensor input.

•D escribe how the solar sensor affects the various output functions.


3/12


INTRODUCTION

Solar Radiation

Solar radiation, from the sun, passes through the earths atm osphere in the form of light

(both visible and non-visible) and heat (sunshine). To date, the influence of solar radiation

on the clim ate control system in the vehicle has only been com pensated for by an average

value stored in the control m odule and based on control settings and outside tem perature

values.

Solar Sensor

The solar sensor can detect the am ount of solar radiation that is influencing the tem pera-

ture and clim ate in the vehicles interior. The IH KA control m odule m onitors the input from

the solar sensor and adds the value to its processing factors. The settings of the clim ate

control system are changed to com pensate for this additional influence.

The settings of the follow ing IH KA com ponents are adjusted to com pensate for changesin solar radiation:

•Blow er - The blow er curve is changed

•Stratification (m ixing flaps) - The stratification outlet air tem perature is changed (not E46)

•Ventilation - The opening angles of the ventilation flaps are changed.


4/12


Components of the System:

In the E38, The solar sensor is integrated in the housing of the anti-theft w arning system

LED . The w arning indicator LED is installed on the outlet grille in the top center of the

instrum ent panel w here solar radiation can directly reach the solar sensor.

The D W A LE D w ith solar sensor is an additional w iring harness w ith a 4-pin plug connec-

tor.

DWA LED with integrated solar sensor

__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

1

2 3

D W A LED plug connector

4-pin solar sensor plug connectorD W A LE D /S O L AR S E N S O R M O D U L E


5/12


The solar sensor consists of tw o photoresistors, w hich are integrated on the left and right

sides of the D W A housing next to the D W A LED . The photoresistors sense the different

intensity levels of the solar radiation.

DWA LED dismantled; housing and pc-board with LED and solar sensor housing

1 The photoresistor on the right is fitted underthe plastic cover

2The photoresistor on the left is fitted under theplastic cover

3 PC -board, D W A LED and solar sensor4 D W A LED housing

The E46 solar sensor is located in the right

defroster outlet at the base of the w indshield.

The E46 sensor contains one photoresistor for

sensing solar radiation.

1

2

3

4

SOLAR SENSOR


6/12

System Operation

The solar sensor receives pow er (5 volts) and ground from the IH KA control m odule. The

m odule then reads the voltage drop across the photoresistor and determ ines the degree of

solar heating based on the change in voltage. The voltage drop across the photoresistor

increases as solar radiation increases. The IH KA control m odule m onitoring voltage w ill

decrease indicating an increase in solar heating. The m odule processes the input every 10

seconds and checks it for plausibility based on a lim it value m onitoring function.

Values outside the lim it indicate a m alfunction and the signal from the sensor is ignored by

the m odule.

As solar radiation levels increase, the control curves, stored in the IH KA m odule, for the

blow er fan, m ixing flaps and ventilation (face vent) flaps are shifted to com pensate for the

additional heat.

The solar sensor inputs to the IH KA control m odule can influence the settings on the rele-

vant side (driver/front passenger) on the E38 and E39. N o separate regulation is possible

on the E46.

W hen driving at night, during cloudy periods or through tunnels, the control m aps are shift-

ed back to their base settings.



7/12


CONTROL CURVES OPERATION

Blower Intervention

The graph below illustrates the solar influence on the blow er fan w ith a constant Y factor

and the solar influence changing from 0 th 100% .

Blower power curves

The m iddle curve illustrates a blow er curve w ithout any solar influence. At a constant Y fac-

tor of 20% , the solar influence on the IH KA control m odule w ill cause the blow er curve to

shift as the radiation increases from 0 to 100% .

W ith a solar influence of 0% , curve “B”is used, providing 25% pow er to the blow er.

As the solar influence increases, the curve shifts upw ard until the solar influence reaches

100% . At this point, curve “A”is used providing 36% pow er to the blow er.

D uring heating, the blow er pow er decreases as solar influence increases.

W hile cooling, the blow er pow er w ill increase as solar influence increases.


8/12


Stratification (Temperature Intervention) E38 only

The m ixing flaps w ill open less in the direction of heat for blending air as the solar influence

increases. The graph below represents the influence of the solar sensor on the stratification

flap settings

To illustrate the influence of the solar sensor on the m ixing flap position, the Y factor rem ains

constant at 20% .

W ith a solar influence of 0% curve “A”is adopted for the various outside tem peratures. As

the outside tem perature decreases, the m ixing flap is m oved tow ard the w arm er setting

blending m ore heat.

W ith a solar influence of 100% curve “B”is adopted for the various outside tem peratures.

As the outside tem perature decreases, the m ixing flap is still m oved tow ard the w arm er set-

ting but it does not m ove as far. The solar influence is com pensating to provide the sam e

com fort level.

W ith the m ixing flap thum bw heel at 100 or 0% (full hot or cold), the flaps are in the default

position and there w ill be no solar influence.

The left and right m ixing flaps are controlled independently based on the individual settings

and left and right solar sensor inputs.


9/12


Ventilation Intervention (Center Vent Air Distribution)

The influence of the solar sensor on the ventilation flaps is show n in the graph below .

The norm al curve “B”applies w hen there is no solar sensor influence 0% , or if the sensor

is defective.

The m axim um curve “A”applies w hen the solar influence is 100% .

The ventilation flaps w ill close less as the solar influence increases. This allow s m ore cool

air from the center vents as the solar radiation increases.

This adjustm ent is also independently adjustable on the E38 based on the left/right solar

sensor inputs.


10/12

DIAGNOSIS

Troubleshooting of the solar sensor (left/right) is carried out through the IH KA diagnostic

program using the D IS or M oD iC .

Status displays for the solar sensor input are available in percentages. The status displayscan be checked w hile applying a light or heat source to the solar sensor to view the changein value.

The E436 diagnostic program for the IH KAsystem contains a test m odule B 6450-00011 for testing the operation of the solarsensor.

The IH KA control m odule m onitors the solar sensor and w ill set a fault code for:

•Shorts to B + or ground•O pen circuits

The IH KA control m odule w ill function as a system w ithout solar influence correction if thesensor is defective.

R ecognition of the solar sensor and its influencing capabilities is enabled via ZC S coding.R em em ber to adopt the code w henever possible to avoid loosing car/key m em ory functionchanges. Also the IH KA control m odule m ust be disconnected from B + before coding canbecom e perm anent.



11/12


REMOVAL HINTS

E38 vehicles

To rem ove the solar sensor from an E38, refer to TIS - R M 6422161, rem oval of the center

outlet grille at the top of the dash. After rem oval of the grille, disconnect the plug connec-

tor of the D W A indicator and solar sensor and pull the sensor from the grille.

E46 vehicles

R em oval of the E46 solar sensor requires rem oval of the instrum ent panel. H ow ever, for

testing purposes the connector is locates inline attached to the harness connector X610.


12/12

REVIEW QUESTIONS

1. W hat is the advantage of using the solar influence in the operation of the IH KA control

system ?

______________________________________________________________

______________________________________________________________

2. W hat are the three functions of IH KA operation influenced by the solar sensor input cor-

rection factor?

_____________________________________________________________

_____________________________________________________________

_____________________________________________________________

3. W hat function is not corrected for w ith the E46 IH KA system ?

____________________________________________________________

4. H ow can you test the operation of the solar sensor?

____________________________________________________________

____________________________________________________________


e46 solarsensor

Documents