No description available.

No description available.

No description available.

No description available.

The work presented herein describes thesis research in an on-going camshaft grinding evaluation study, initially under the sole sponsorship of Ford Motor Company, and subsequently under the auspices of the National Science Foundation, with industrial participation from American Stress Technologies, Ford Motor Company, G.E. Superabrasives and Litton Automotive Services. Six mechanically assembled camshafts were ground with each of their eight induction hardened lobes receiving a different depth of cut per pass. X-ray residual stress measurements made with depth identified significant near-surface tensile residual stresses in abusively ground regions of the lobes. Acid etching at the time of grinding and subsequent microhardness measurements were employed to verify the x-ray depth results. The grinding operation was further characterized with use of profile and roughness measurements. Burn (defined as a localized tempering of the cam lobe as a result of the grinding operation) appeared in those lobes that received the larger depth of cut, and was concentrated along the ramps and base circle. Several non-destructive examination techniques were then compared with each other to discover which best detected burn. Intercomparison involved evaluating the strength and consistency of the measurement signal. Background noise occurred in all cases due to the measurement technique, instrument error, and human error. Measurement of grinding forces and x-ray diffraction line width analysis were found to be suitable for rapidly and reliably detecting grinding burn in the induction-hardened carbon steel cam lobes. In this regard, it may now be possible to have reliable, quantitative, and non-destructive cam lobe examination in place of the traditional acid etching. / Master of Science

The source-to-wheel efficiency of today’s electrified vehicles already far surpasses the efficiency of strictly gasoline vehicles. As sources of electricity become cleaner and more efficient, and as gasoline becomes more scarce, the need for transportation electrification is increasingly economically and environmentally driven. The automotive industry primarily makes use of permanent magnet synchronous machines (PMSMs) and induction machines (IMs), the latter has the cost advantage of containing no rare earth metals. This thesis studies two different induction motors for electrified powertrain applications using a novel optimization algorithm to create efficiency maps and compare the efficiencies of the two motors. Induction motors are difficult to banchmark due to their complicated control schemes. Each point in their operating range can be achieved with an infinite number of current/slip combinations and therefore has infinite potential efficiencies. The proposed algorithm limits the number of simulations needed to benchmark an induction machine, and provides a clear and unbiased way to compare machines based on losses at their most efficient current/slip combinations over their entire operating range. The proposed algorithm is able to calculate losses within 5% accuracy of simulation values for both machines. The first motor studied makes use of stranded windings and geometry parameters from the Tesla Motors patents. The efficiency map created has a peak efficiency of 96% and corresponds closely to an efficiency map for a similar motor found in literature. The second motor makes use of copper bar windings, which are easier to manufacture and have lower material costs. Bar windings, typically have lower resistance and stator copper losses at low speeds, but higher effective resistance and stator losses at high speeds due to eddy effects. The motor modelled was intended simply to compare the stranded and bar windings, and to see the advantages and disadvantages. For this reason, no other changes are made to the winding layout or motor geometry, including changes that would reduce the eddy effect. The resultant efficiency map has a peak efficiency of only 90%, performing worse than the stranded wound motor across most of its operating range. At very low speeds, under 1000 rpm, the efficiency of the bar wound machine is better than that of the stranded machine. The bar wound machine also has the advantage of being over 80% efficient everywhere. The author suggests that future research focus on applying the proposed benchmarking algorithm to stator bar motors designed to limit eddy effects. Strategies include changing the slot opening shape, increasing the number of stator bars, and moving the stator bars away from the air gap. / Thesis / Master of Applied Science (MASc)

No description available.

A gas-phase system to oxidize and remove the platinum and palladium from automotive catalytic converter units was studied. The effects of varying reaction temperature, time and reactant gas concentration upon yields were monitored using a colorimetric procedure based on the regent p-nitroso-N, N-dimethyl amiline. Chlorine plus carbon monoxide at 700°-900°C. displayed the most promise for commercial application.

Solid rocket motors consist of a thin metallic or composite shell filled with a soft rubbery propellant. Such motors are vulnerable and prone to buckling due to sudden external pressures produced by nearby detonation. The stability conditions of rocket motors subjected toaxisymmetric, external pressure loading are examined. The outer cases of motors are considered as isotropic (metallic) or anisotropic (composite), thin and high-strength shells, which are the main structures of interest in the stability analyses. The inner, low-strength elastic cores are modeled as linear and nonlinear elastic foundations. A general, refined, Sanders' nonlinear shell theory, which accounts for geometric nonlinearity in the form of von Karman type of nonlinear strain-displacement relations, is used to model thin-walled, laminated,composite cylindrical shells. The first order shear deformable concept is adopted in the analyses to include the transverse shear flexibility of composites. A winkler-type of linear and nonlinear elastic foundation is applied to model the internal foundations. Pasternak-foundation constants are also chosen tomodify the proposed elastic foundation model for the purpose of shear interactions. A set of displacement-based finite element codes have been formulated to determine critical buckling loads and mode shapes. The effect of initial imperfections on the structural responses are also incorporated in the formulations. A variety of numerical examples are investigated to demonstrate the validity and efficiency of the purposed theory under various boundary condiitions and loading cases. First, linear eigenvalue analysis is used to examine approximate buckling loads and buckling modes as well as symmetric conditions. An iterative solution procedure, either Newton-Raphson or Riks-Wempner method is employed to trace the nonlinear equilibrium paths for the cases of stress, buckling and post-buckling analyses. Both ring and shell-type models are applied for the structural analyses with different internal elastic foundations and initial imperfections. / Ph. D.

In the last two decades there has been a revival of interest in variable reluctance drives mainly due to the advent of high power semiconductor devices and improvements in the understanding of the principles of electromagnetic energy conversion. In particular, the switched reluctance motor (SRM) has received attention mainly due to its simple construction and robustness when compared to other variable-speed drives. Considerable research has been done on topics ranging from the design to the control of the motor. Due to the high nonlinearity of the machine, even the prediction of the steady-state performance of the drive has been difficult. In the attempt to overcome the nonlinearity problem, researchers have resorted to computer solutions. The Finite Element Analysis (FEA) method has been used to predict the steady state performance of the motor. While this has improved the accuracy of performance prediction, it is very time intensive. This is unacceptable in an industrial situation where the PC is the main design tool. The need for analytical methods therefore exists. An analytical method for the steady-state performance prediction of the SRM drive based on an improved method for estimating the maximum and minimum inductances is described. This method is extended to include determination of the motor inductances at any rotor position and subsequently, the prediction of the steady-state average torque. The work also proposes an analytical method for determining the core losses of the SRM. Considerable effort is also dedicated to the design and analysis of new and old SRM converter topologies with particular attention to the criteria governing the choice of converter topology, the prediction of key waveforms, the criteria for selecting power semiconductor devices and the determination of device ratings. A novel method for the direct steady-state analysis of the SRM drive without going through the transient solution is proposed. The effect of motor geometry on converter ratings is also investigated for the common SRM pole combinations. Novel methods for the measurement and instrumentation of SRM are also described. Theoretical predictions are verified by experimental results using a 6/4 pole prototype switched reluctance motor. / Ph. D.