Every sub-component of a diesel injector must perform optimally to ensure maximum fuel economy and minimum particulate and carbon-dioxide emissions. Continually developing emissions standards will drive manufacturers to guarantee fuel system performance for a significant period of the unit lifetime. Key to implementing such systems will be the ability to compensate for unit changes in use. This thesis investigates possibilities for developing existing unit and sub-component characterization techniques to enable robust performance over an extended duration. An overview of existing injector characterization techniques is given, along with possibilities for enhancement of the existing state of the art through development of measurement systems widely used within the industry. Particular attention is paid to developing methods to allow testing of injectors and sub-components under representative conditions, where system pressures of 3000 bar are commonplace. Consideration is given to the benefits of moving from existing methods, based on steady-state testing, towards dynamic transfer function testing, and methods reliant on real-time sub-system feedback, to enable better characterization of the unit in use. Key to the development of enhanced characterization will be feedback from the electrohydraulic valves operating inside the injector. These valves are critical to current heavyduty injector designs. To enable full understanding of the unit’s operation, the thesis develops mathematical representations of such component’s functionality. Software models of these systems are offered, and various model simulations discussed. Possibilities for refining these are also provided. Within this thesis the available mechanisms for taking valve position feedback measurements capable of detecting valve lifts of <30 μm with suitable resolution and accuracy are discussed. The results of experiments with various sensing devices are then presented. Subsequently, novel methods for taking measurements using the unit stator as a sensing element are developed, described in terms of mathematical models, and tested in software simulations. Sensing experiments using valve hardware are then described. The thesis closes with a discussion on important future trends in fuel system development.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:589837 |
| Date | January 2013 |
| Creators | Lillington, Richard |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/58445/ |
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