This thesis presents a novel ultrasonic instrument for non-invasive and in-situ characterization of journal bearing lubricant viscosity. In particular, the application to journal bearings is described by non-invasively measuring the viscosity and localized power losses throughout operation. This ultrasonic viscometer is based on the reflection of polarized shear waves from a thin resonating coating layer to increase the measurement sensitivity, in comparison to conventional ultrasonic methods. This instrument allows for a full engine oil viscoelastic characterization in-situ. The book investigates the effects of temperature, pressure and shear rate, and describes in detail the ultrasonic setup and method. Further, it demonstrates that the same technique can be applied similarly to monitor the lubrication of other engine components. As such, it offers a unique instrument that can drive the research of oil formulations to improve engine performance and fulfill the requirements of international fuel economy regulations.

Updated, revised, and restructured to reflect the latest advances in science and applications, the fourth edition of this best-selling industry and research reference covers the fundamental physical acoustics of ultrasonics and transducers, with a focus on piezoelectric and magnetostrictive modalities. It then discusses the full breadth of ultrasonics applications involving low power (sensing) and high power (processing) for research, industrial, and medical use. This book includes new content covering computer modeling used for acoustic and elastic wave phenomena, including scattering, mode conversion, transmission through layered media, Rayleigh and Lamb waves and flexural plates, modern horn design tools, Langevin transducers, and material characterization. There is more attention on process monitoring and advanced nondestructive testing and evaluation (NDT/NDE), including phased array ultrasound (PAUT), long-range inspection, using guided ultrasonic waves (GUW), internally rotary inspection systems (IRIS), time-of-flight diffraction (TOFD), and acoustic emission (AE). These methods are discussed and applied to both metals and nonmetals using illustrations in various industries, including now additionally for food and beverage products. The topics of defect sizing, capabilities, and limitations, including the probability of detection (POD), are introduced. Three chapters provide a new treatment of high-power ultrasonics, for both fluids and solids, and again, with examples of industrial engineering, food and beverage, pharmaceuticals, petrochemicals, and other process applications. Expanded coverage is given to medical and biological applications, covering diagnostics, therapy, and, at the highest powers, surgery. Key Features Provides an overview of fundamental analysis and transducer technologies needed to design and develop both measurement and processing systems Considers applications in material characterization and metrology Covers ultrasonic nondestructive testing and evaluation and high-power ultrasonics, which involves interactions that change the state of material Highlights medical and biomedical applications of ultrasound, focusing on the physical acoustics and the technology employed for diagnosis, therapy, surgery, and research This book is intended for both the undergraduate and graduate scientists and engineers, as well as the working professional, who seeks to understand the fundamentals together with a holistic treatment of the field of ultrasonics and its diversity of applications.

Piston ring-liner contact in an internal combustion engine highly influences the amount of friction, oil consumption and wear that occurs. Proper lubrication of this contact is, therefore, necessary and is an important research area for the engine manufacturers to improve fuel efficiency and achieve the emission reduction targets proposed by authorities. However, the lubricant film formed in piston ring-liner contact is very thin and its measurement is challenging. Although the computer simulations, a low cost tool, are widely used to estimate the piston ring-liner interactions, they require a robust data for the validation of the mathematical models. In the past several techniques based on optical or electrical characteristics of the lubricant have been developed and applied to measure lubricant film thickness in piston rings, such as capacitance, resistance, eddy current and laser induced fluorescence methods. The main characteristic of these techniques is that they are invasive and require access to the piston ring-liner contact, and so penetrate the cylinder liner. Hence these measurement methods disturb the nature of the contact and influence ring lubrication. This thesis demonstrates the development of a novel ultrasonic method for non-invasive measurement of oil films within the piston ring contacts and the feasibility of the technique on a reciprocating test rig and a fired engine. After successful implementations of ultrasonic technique, the investigation results showed that the ultrasound technique can be used for the piston ring film thickness measurement. The ultrasonically measured film thickness values were consistent with those of other published data in the literature. The effects of load, speed and viscosity on the lubricant film formation were shown in the reciprocator tests. The investigation of the single cylinder engine test showed that the bespoke ultrasonic sensors could survive at high temperature that liner exterior surface experienced. The minimum lubricant films between the compression ring and liner were measured during the engine's power stroke and were typically less than 1 μm at TDC and ~4 μm at mid stroke. It has been shown that the ultrasonic technique demonstrates significant promise as a non-invasive and effective tool to assess the lubricant condition within the ring-liner contact. As being insensitive to test environment and more compact technique compared to the current measurement technologies, the ultrasonic method has a potential to be employed in a test vehicle.

Scientists and engineers consider how the lower starting temperature of new engine designs will impact the flow of oil through them, and how new oil can be developed to address the changes. Seven of the 11 papers, presented to a June 1999 symposium in St. Louis, Missouri, report on a study by a comm

Internal combustion engines are perhaps the most ubiquitous power source in the modern world. Their heavy use in the vehicle industry and the current impetus to improve efficiency whilst reducing emissions means that OEMs are driving research to provide cleaner and 'greener' engines. Though significant effort is being channelled into teasing out improvements in thermodynamic Efficiency by such methods as pressure boosting and power management. the nature of an engine means many moving parts contribute to parasitic frictional loss. Of these interfaces. the reciprocating contacts between cylinder. piston rings and skirt are arguably subject to the most demanding tribological conditions within an engine. required to seal against the high temperature' combustion gases whilst supporting the large side loading inherent to the system. Given that the piston of an engine may perform this action hundreds of millions of times in its lifespan. the lubrication strategy and component design is of key importance in minimising wear frictional losses. Though the use of numerical simulation tools for improving design has seen significant growth as computational capabilities improve and provide cost advantages to full scale testing. robust validation methods are required to guide the development of the underlying models. The aim of this project was to assess the suitability of an ultrasonic method to monitor the condition of lubrication at the aforementioned contacts by measuring film thickness. Though various techniques involving optical and electrical principles have been employed in the past they generally require the cylinder of the engine to be penetrated and implementation. for the most part. is limited to the test cell. The results of investigations at the piston ring contact have shown that the ultrasonic technique can be used to measure lubricant film thickness and have shown the influence of cylinder pressure and reciprocating speed. Measurements correlate well with work by other authors using the alternative methods mentioned. giving confidence in the robustness of the method. Film measurements at the skirt have been also been successful. not only in quantifying the minimum films present. but also in detailing the profile of the film over its surface and enabling some of the secondary motions of the piston to be deduced. It has been shown that the ultrasonic technique offers the ability and freedom to measure film thickness within an operational engine whilst having the distinct advantage of limiting the degree structural modification required. It shows promise as a research tool and with further development. offers the potential to be incorporated into a lubricant monitoring and control System to help reduce friction losses and emissions.

Two ASTM standards have been developed for the measurement of engine oil viscosity at high temperature (150°C) and high shear rate (106 s-1) using rotational viscometers. Both methods resulted from significant international participation at the working group level. One test method resulted from work done primarily within ASTM Committee D-2, Subcommittee 7, using the tapered bearing simulator. The other resulted from work done within the Co-ordinating European Council (CEC) using the Ravenfield viscometer, herein called the tapered plug viscometer. The chronological development of each standard is reviewed, and test method and precision are compared. Expansion of measurement capabilities are discussed with regard to the study of lubricant rheology and engine performance.

Radiometric techniques have been developed and successfully applied to journal bearing studies in a unidirectional bearing test machine. These techniques, which involve the detection of wear debris from a radioactive (113Sn ) test bearing, were used to determine bearing load capacity with both Newtonian and non-Newtonian lubricants. Results indicate that the radiometric method can rapidly provide information that correlates with other laboratory and engine test data.

Engineers, scientists, and technologists will find here, for the first time, a clear and comprehensive account of applications of ultrasonics in the field of process control. Using numerous examples of high-volume, low-cost applications, the author illustrates how the use of new transducer materials and designs, combined with microprocessor-based electronics, make technical and financial sense for concepts that only a few years ago might have been of interest only to academicians. Some of the important topics covered include coupling, acoustic isolation, transducer and sensor design, and signal detection in the presence of noise.