This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Optimization Potential of the Common Rail Fuel Injection for Low-Emission and Low-Consumption Diesel Engines
Technical Paper
1999-29-0006
Sector:
Language:
German
Abstract
As a result of their flexibility in terms of fuel pressure and
injection behavior in an adjusted combustion chamber, common rail
injection system offer much better possibilities for creating
low-consumption, low-emission diesel engines than conventional
injection systems. Before implementing them in future combustion
methods, additional measuring and pretuning systems must be
applied, using state-of-the-art numeric and diagnostic methods,
since it will be impossible to meet future requirements without
these.
This paper shall provide details on the various analysis
procedures for the examination and design of a CR injection system
for passenger cars and on its adjustment to combustion chamber
conditions. The influence of the rail pressure, of the nozzle type,
and of the charge movement on the ignition procedure and the
subsequent combustion and formation of pollutants will be described
and discussed. Ignition studies will be carried out on a
transparent film unit with a serial combustion chamber geometry
using OH emission spectrometry. Combustion, NOx and soot production
will be analyzed using 2D two-color diagnostics. The results
correlate very well with NOx and soot values measured in
single-cylinder studies. These allow for very efficient pre-
optimization of CR injection systems and combustion chamber design.
The impact of the injection rate can also be examined, based on a
comparison between conventional CR injection and the laboratory
sample of a piezo CR injection. The results are evaluated and
optimization criteria for CR injection can be derived.