Introduction

IHKA SYSTEMS - SOLAR SENSOR
E38 IHKA - March 1999 (2000 M/Y)
E46 IHKA - 2000 Model Year
E39 IHKA - 2001 Model Year

Objectives
After studying this handout, you will be able to:

- Describe the operation of the solar sensor as it applies to the IHKA systems.
- List the output functions effected by the solar sensor input.
- Describe how the solar sensor affects the various output functions.

Purpose of the System:







The purpose of the solar sensor is to compensate the climate control system's output for the radiant heating effect of the sun. This will aid the IHKA in maintaining a constant comfort level, in the vehicle's interior, during all driving conditions.

The function of heating and air conditioning systems in BMW vehicles is to provide the driver and passengers a comfortable atmosphere regardless of conditions outside of the vehicle. Based on the temperature signal inputs, blower setting, flaps portioning, program settings in the control module and influencing variables, the IHKA control module is able to process these inputs to achieve the desired comfort level.

The following input variables are processed by the IHKA module:

- Interior temperature
- Heat exchanger temperature
- Ventilation temperature (E38)
- Evaporator temperature
- Air volume setting
- Engine temperature and RPM
- Exterior temperature

The processed variable "Y - factor" is determined by using the above inputs. The Y - factor then represents how much adjustment is necessary by the IHKA module to achieve the set temperature