Thesis-2004-AbdulKarim.pdf (42.71 MB)
Direct injection diesel engine combustion diagnostics
thesis
posted on 2011-01-10, 09:49 authored by Zainal A. Abdul-KarimThe demand for the protection of the environment from air pollution and
reduction of carbon dioxide has resulted in worldwide exhaust emissions
regulations imposed on the diesel engines. Fortunately, diesel engine offers the
best fuel economy and low emissions of carbon dioxide of most engines currently
available. However, the engine's inherent drawbacks are that the engine is
heavy, noisy, and expensive, in addition to producing significant level of
particulates and nitrogen oxides emissions.
The present research attempts to understand the combustion
characteristics and emissions trade-off by experimental investigations of the
diesel engine using a production Lister Petter 2.97 litres, four-cylinder,
high-speed, direct injection diesel engine. The investigation involved the analysis
of the in-cylinder pressure data, heat release rate calculation and exhaust gas
measurements of various injectors having different nozzle geometry. The engine
experiments cover both the investigation of the fuel injection and the engine
operating parameters such as injection rate, nozzle geometry, the engine load
and speed. The effects of each parameter on ignition delay, heat release rate,
nitrogen oxides emissions, smoke density, and total hydrocarbon levels were
investigated. Two complementary diagnostic techniques were employed in order
to assist in understanding the injection characteristics. The first technique
involved the imaging of the fuel sprays from the different injectors in a constant
volume spray chamber using a CCD camera. The images were than process
using a dedicated image processing software. The second technique involved
the measurements of the fuel injection rates from the injectors using the Bosch
Tube meter. A three-zone model was developed to determine the heat release rate of
combustion. The cylinder pressure data was used to validate the model written in
Matlab computer programme. The model is based on the principles of the First
Law of Thermodynamics applied to the three zones, formed due to the fuel
injection into the combustion chamber. The heat release rate profiles produced
by the model were used to analyse the formation of pollutants that were
measured in the exhaust gas.
The results showed that injectors with large nozzle hole diameters
produced high smoke levels, especially at high engine load conditions with small
increase in NOx. These injectors also caused the sprays to impinged on the
combustion chamber walls at high load conditions. On the other hand, injectors
having small nozzle hole diameters produced high levels of NOx while the smoke
emission levels were low. The effect of nozzle geometry has little significant on
the emissions of THC.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Aeronautical and Automotive Engineering
Publisher
© Zainal Ambri Abdul-KarimPublication date
2004Notes
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.416608Language
- en