Title:
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Emission characterization and cylinder pressure information for applications in the electronic engine management of diesel engines
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In the last few years, diesel engines for passenger cars and light commercial
vehicles have achieved in Europe a level of success as never before and, to-·
day, several manufacturers are looking at the US market for the close future.
This has been possible thanks to the exploitation of turbocharging systems
and highly flexible fuel injection equipment which have increased the specific
power output of the engine, reducing in the same time the combustion noise
and maintaining the high level of fuel efficiency typical of this kind of powertrain.
On the other hand the complexity of diesel engines has increased
exponentially, with the addition of several sensors and actuators necessary
to monitor and control the correct working of the system.
In order to achieve the increasing emission targets requested by European
and US regulations, it is necessary not only to optimize the calibration of
all the engine parameters, but also to ensure that the calibration setpoints
are always achieved through an accurate control system. Moreover, it is
necessary to be able to estimate how the tolerances errors of the engine
sensors and actuators, inevitable in mass production equipment, will affect
the robustness of the final engine outputs.
In this thesis, experimental investigations have been executed on two different
direct injection diesel engines, in order to characterize their emission behaviour and create some general prediction functions for the engine-out
emission levels, based on mean value variables. These functions can be easily
implemented in power plant engine models, in order to investigate the effect
of deviations of single components on the whole engine system. Moreover,
an explorative investigation has been carried out on the possible exploitation
of in-cylinder pressure data for improving the control of the fuel injection
and combustion, achieving an overall engine robustness advantage.
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