Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Stephen Gregory Poulos. / M.S.

Government legislation on particulate matter (PM) and oxides of nitrogen (NOX) emissions have become increasingly stringent over the past decades. Future projections have led to internal combustion (IC)engine developers exploring advanced combustion technologies which may replace or supplement current state of the art systems. Advanced combustion technologies such as Low Temperature Combustion (LTC) cover a broad series of mechanisms that seek to attain in-cylinder Equivalence ratio (f) - Temperature (T) combinations during combustion which lead to acceptable emissions of exhaust PM and NOX. These are generally achieved by a combination of EGR dilution and extended ignition delays for mixture preparation. Another common feature of LTC is the poor combustion efficiency due to severe requirements placed on mixture quality as lower temperatures and oxygen concentrations reduce local ignitability limits. Therefore, a significant amount of work on LTC is centred around understanding the spatial and temporal development of inadequately prepared mixtures during LTC. The investigations presented in this thesis are expected to contribute to this body of work as they are predicated on the hypothesis that current mixture preparation methods are insufficiently adapted to conditions present in LTC combustion modes.

This thesis focuses on the factors which lead to off-shore manufacture of Australian inventions. It establishes this phenomenon as a problem, both in terms of its incidence in the post-war period, and in the strategic importance of innovative activity to economic growth. The thesis utilises a case study approach and concentrates on the experiences of one company, the Orbital Engine Corporation (Orbital). In 1989 Ralph Sarich, inventor of the Orbital Combustion Process (OCP) engine and founder of Orbital, signed an agreement with the Michigan state government to manufacture the engine in the United States of America (USA), in preference to several alternative sites in Australia and overseas. This occurred in the context of Orbital actively pursuing assistance from the Australian government to secure local production. The research question is: Why did Orbital decide to manufacture its engine invention ofshore? A multi-disciplinary approach to this question is adopted. Three different conceptual frameworks are employed: industrial organisation theory, market failure theory and policy network theory. The analysis is not structured around a pre-existing hypothesis; instead, the aim is to generate potential explanations for more rigorous testing by subsequent researchers. The thesis concludes that, in terms of industrial organisation theory, the decision to manufacture OCP engines off-shore was a function of the poor quality of the Australian industrial context and the failure by those seeking assistance from the Commonwealth government to stress Orbital's status as an exemplary enterprise in Australian industry. Market failure theory indicated that offshore production of the OCP engine was made more likely by the suboptimal operation of the price mechanism, the neglect of market failure arguments by those supporting local production of the engine and 'government failure'. Policy network theory explained Orbital's decision as the result of: ineffective employment of negotiation tactics by proponents of the engine's domestic manufacture; and the chaotic nature of negotiations which allowed certain personal and ideological prejudices to dominate the issue resolution process. It is shown that some or all of these explanations underlie a number of other examples where Australian inventions have been manufactured offshore. In commenting on policy implications, the thesis points to the economic potential of the Orbital invention and the value of interventionist industry policy. The thesis identifies a number of actions which might be taken to lower the incidence of foreign manufacture of Australian inventions. Further research is necessary to determine the relative importance of the various factors which are identified as leading to offshore production. In addition, there remains a particularly crucial need to improve the social efficiency of existing cost-benefit techniques employed by government policy-makers and commercial analysts.

A Computational Fluid Dynamics (CFD) simulation of the Bishop Rotary Valve (BRV) engine is developed. The simulation used an existing commercial CFD code, CFX 4.3, with a number of new routines written to allow it to simulate the conditions and motions involved in an internal combustion engine. The code is extensively validated using results from other researchers, and several new validations are performed to directly validate the code for simulating internal combustion engine flows. Firstly, tumble vortex breakdown during the compression stroke of a square piston model engine is modelled. The results of the simulation are validated against published high quality experimental data. Both two- and three-dimensional models are tested, using the k-e and Reynolds stress turbulence models. The Reynolds stress turbulence model simulations successfully predicted the tumble break down process during the compression stroke. A simple three-dimensional Large Eddy Simulation model is also presented. The numerical simulation is then applied to the BRV engine. An in-cylinder flow field not previously described is discovered, created by the unique combustion chamber shape of the BRV engine. The flow field is not adequately described by the traditional descriptions of engine flows, being squish, swirl and tumble. The new flow structure is named 'dual cross tumble', and is characterised by two counter-rotating vortices in the cross tumble plane on either side of the inlet air jet. Analysis of the dual tumble structure indicates that it is most beneficial in high bore to stroke ratio engines. This flow structure has been predicted or visualised by a small number of previous researchers, however no published research has recognised its significance or potential benefits. The validated code is then used to predict the effect of modifying the valve cross sectional area, the effect of the inlet manifold wave, the effect of heat transfer from the inlet manifold walls, the effect of bore to stroke ratio, and the effect of engine speed. This work presents a numerical simulation of a new rotary valve engine technology. This opens up a whole new area of engine aerodynamics research as no detailed examination of the flows in a rotary valve engine have been presented previously. In the process, it discovers a new compression stroke turbulence generation mechanism, 'dual cross tumble', which offers the potential of performance levels not possible using poppet valve engines.

Not available / text

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Not available / text

No description available.

The present research describes an investigation of the flow through the inlet port and the cylinder of an internal combustion engine. The principal aim of the work is to interpret the effects of the port shape and valve lift on the engine's "breathing" characteristics, and to develop a better understanding of flow and turbulence behaviour through the use of Computational Fluid Dynamics (CFD), using a commercial available package STAR-CD. A complex computational mesh model was constructed, which presents the actual inlet port/cylinder assembly, including a curved port, a cylinder, moving valve and piston. Predictions have been carried out for both steady and transient flows. For steady flow, the influence of valve lift and port shape on discharge coefficient and the in-cylinder flow pattern has been examined. Surface static pressures predicted using the CFD code, providing a useful indicator of flow separation within the port/cylinder assembly, are presented and compared with experimental data. Details of velocity fields obtained by laser Doppler anemometry in a companion study at King's College London, using a steady flow bench test with a liquid working fluid for refractive index matching, compared favourably with the predicted data. For transient flow, the flow pattern changes and the turbulence field evolutions due to valve and piston movement are presented, and indicate the possible source of cyclic variability in an internal combustion engine.

A Computational Fluid Dynamics (CFD) simulation of the Bishop Rotary Valve (BRV) engine is developed. The simulation used an existing commercial CFD code, CFX 4.3, with a number of new routines written to allow it to simulate the conditions and motions involved in an internal combustion engine. The code is extensively validated using results from other researchers, and several new validations are performed to directly validate the code for simulating internal combustion engine flows. Firstly, tumble vortex breakdown during the compression stroke of a square piston model engine is modelled. The results of the simulation are validated against published high quality experimental data. Both two- and three-dimensional models are tested, using the k-e and Reynolds stress turbulence models. The Reynolds stress turbulence model simulations successfully predicted the tumble break down process during the compression stroke. A simple three-dimensional Large Eddy Simulation model is also presented. The numerical simulation is then applied to the BRV engine. An in-cylinder flow field not previously described is discovered, created by the unique combustion chamber shape of the BRV engine. The flow field is not adequately described by the traditional descriptions of engine flows, being squish, swirl and tumble. The new flow structure is named 'dual cross tumble', and is characterised by two counter-rotating vortices in the cross tumble plane on either side of the inlet air jet. Analysis of the dual tumble structure indicates that it is most beneficial in high bore to stroke ratio engines. This flow structure has been predicted or visualised by a small number of previous researchers, however no published research has recognised its significance or potential benefits. The validated code is then used to predict the effect of modifying the valve cross sectional area, the effect of the inlet manifold wave, the effect of heat transfer from the inlet manifold walls, the effect of bore to stroke ratio, and the effect of engine speed. This work presents a numerical simulation of a new rotary valve engine technology. This opens up a whole new area of engine aerodynamics research as no detailed examination of the flows in a rotary valve engine have been presented previously. In the process, it discovers a new compression stroke turbulence generation mechanism, 'dual cross tumble', which offers the potential of performance levels not possible using poppet valve engines.