'Plundering around somewhere on this forum...
'Stumbled upon some of what I think are gsxr's shop notes
(Yeah,
www.w124performance.com)
One of which is a treatise from Beru included in are these statements:
35
10
Combined systems
Ionic current measurement
Controlled glow systems
Glow plugs are the right starting aid to guarantee a fast
start of the diesel engine with the lowest possible strain on
the on-board network. In addition, the electrical heating
flanges that are used mainly in heavy commercial vehicles
also have potential for personal vehicle use:
to avoid warm-up emission
to increase smooth engine running
to improve the load acceptance
A combination of both systems is conceivable - for a fast
start with minimal emissions and maximum smooth running
- especially with a view to the fact that the statutory
regulations on emission values are being tightened continually.
The glow plug can be used to measure the ionic current in
diesel engines due to its good position. Accordingly, it is
not necessary to introduce an additional probe into the
combustion chamber. If the heating rod of the glow plug
body is insulated and voltage is applied, an electric field
forms around the tip of the glow plug in the combustion
chamber. The charge of the particles in this field leaks out
of the electrodes. With a suitable circuit, this current can
be measured, amplified and finally transferred to the engine
control device in a treated form.
Possible areas of application:
Identification of combustion interruption
Equation of cylinders in terms of the start of combustion
and the balancing of tolerances in the injection and
suction system
Satisfaction of OBD requirements through direct
feedback from the combustion chamber
Compensation of differing fuel qualities
Electronically controlled systems will gradually replace the
self-regulating glow plugs. Intensive research is being
carried out on the development of suitable systems that do
not require any complex calculation of the control output
in dependence on the engine parameters. In the future, the
upstream engine control device will only communicate the
glow requirements to the glow control device in the form
of a target value; the glow control device then applies the
required voltage to the glow plug. Special glow plugs will
be developed for this purpose, which are able to report
back to the glow time control device a stable temperature
signal than can be analysed easily.
If y'all are already cognizant of this info,'Sorry for re-posting.