issue 63 - Camberley Auto Factors Ltd

TECHNICAL
THIS ISSUE
Electronic
Control
Units
Typical ECU
Example of
ECU internals from 1967
Current day ECU internals
Engine
Management
Centre
Engine Management Phoneline 023 9221 0020
12 :: INDEPENDENT
As vehicle technology continues to evolve, components are
becoming more sophisticated. These components are becoming
increasingly common in vehicles entering the aftermarket and
are no longer restricted to being available from main dealers.
In this ongoing feature, our Engine Management Centre
specialists explain all about ECU’s.
HISTORY
The concept of using a single unit to control multiple functions on an engine, dates
back to the 1930’s, with the development of the Kommandogerät (translated
“command-device”) by BMW for use on their 801 radial aircraft engine. Although the
unit was mechanical-hydraulic as opposed to its modern electronic counterparts, it
was one of the first systems to automatically control multiple engine functions. These
functions included fuel flow, propeller pitch, supercharger setting, mixture and ignition
timing, all in response to a single throttle lever.
The use of a single control unit did not make its way into the automotive field until the
advent of microelectronics. One of the first widespread systems to utilise an electronic
control unit was the KE-Jetronic system developed by Bosch in the late 1980’s to
comply with the introduction of emission standards.
ANATOMY
Modern Engine Management systems have had to evolve in order to cope with such
changes as tighter emission standards, demand in better fuel economy, better
safety systems, in car entertainment and driver aids, to name a few. To do this the
systems now utilise multiple control units to deal with the demand on the system.
These systems can be extremely varied but usually comprise a main control unit
connected to multiple other control units/modules fitted to individual systems like
the ABS system, satellite navigation, diesel pump, parking systems and many more.
PRECAUTIONS
• Some control units have technical restrictions due to the incorporation of
security systems which can limit the availability to the vehicle agent.
• Most control units without trade restriction can be tested.
• Control units can be very sensitive so great care must be taken when replacing
or working with them or vehicle electrical systems.
• Some control units will require coding to the vehicle once fitted.
• Some control units require a continuous power source while undergoing
diagnostic tests.
Exclusive News for the Independent Garage Trade