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Mechanical Engineering

John Moskwa, Matt Snyder, and John Lahti

From left: Professor John Moskwa and graduate students Matt Snyder and John Lahti sit in front of the Powertrain Control Research Lab's novel "hardware-in-the-loop" transient test system. The researchers say the new system will dramatically reduce engine development costs. (27K JPG)

New engine system drives design

Designing new engines can be expensive for vehicle manufacturers, in part because of the many steps and extensive tests required for their development. But researchers at the Powertrain Control Research Laboratory (PCRL) have developed a new transient test-system concept that promises to dramatically reduce engine development costs.

Led by Professor John Moskwa and graduate students John Lahti and Matt Snyder, researchers have designed a "hardware-in-the-loop" system that combines a single-cylinder engine, a unique high-bandwidth transient dynamometerand detailed real-time software that simulates a multi-cylinder engine. The result is a "virtual" multi-cylinder engine. The technology, which has been patented, is a first in a program to reproduce the dynamics of a multi-cylinder engine onto a single-cylinder test engine, and to include the best attributes of both of these engines in one system.

This new system offers many advantages over systems currently used by engineers and researchers in both industry and academia worldwide. For example, the invention allows many tasks or tests in the engine development process to be moved forward in time, because the new system replicates the attributes of a multi-cylinder engine. This significantly shortens the development process and reduces costs.

Currently, most engine manufacturers are reducing or limiting their use of single-cylinder engines because much of the development that is done on these engines must be reworked on the multi-cylinder engine due to their differences in operation. The new PCRL invention causes these engines to operate in the same manner, so development on the single-cylinder engine can be directly carried over to the multi-cylinder engine. The new system also performs transient tests, such as standardized emissions tests, not previously possible. There is now a seamless transition between these two types of engines.

For his research, Moskwa has been given the Innovative Practice Award from the Dynamic Systems & Control Division of the American Society of Mechanical Engineers, and Moskwa and Lahti recently won the Powertrain Excellence Award from the International Council for Powertrain Engineering and Management at the Global Powertrain Congress.

New sensors promise improved applications

Shear-strain sensors are needed in a variety of applications, such as tactile sensing for robotics, remote hazardous materials handling, and detection of fluid flow. But many of today’s shear-strain sensors are either limited in their applications, cannot be assembled in arrays, or are expensive to use.

Assistant Professor Yuri Shkel has developed a novel class of strain sensors that can be used for a variety of sensing needs. Shkel's strain sensors are aimed at detecting shear deformation in nearly any kind of dielectric — or non-conducting — material, such as plastics, organic polymers, resins, paints, clay materials and biological materials.

The sensor is a solid-state, single-plate device in which pairs of electrodes are positioned in close proximity to the material being measured. The strain sensors can then detect "electrostriction" — essentially what occurs with dielectrics when the material undergoes shear deformation.

Shearing strain, or deformation, is what occurs when material is attached to something and force is applied along the surface. Shkel says the new strain sensors can be made very small — 100 microns in size — and can be used on nearly any kind of dielectric material of any size, shape or characteristic.

And because the technology behind the sensors is relatively simple, they could be manufactured at a lower cost than current sensors.

Slicing up a new way to cut cheese

A novel laser technique shown to effectively cut slices of cheese may have expanded uses in other industries. Assistant Professor Xiaochun Li, along with graduate student Hongseok Choi, has adapted a so-called "cold-laser machining" technique, primarily used in laser eye surgery, to the task of cutting Cheddar cheese. Li contends that the advance holds real promise as a clean, precise and cost-effective way to cut cheese commercially, especially into very thin slices.

Li's use of cold-laser machining has caught the eye of other industries that want precise tools for cutting with little or no residue or burning. Among those interested in the technology are textile manufacturers, says Li, who want to use cold-laser technology for cutting fabric.

Lasers are devices that produce tight beams of light energy in units called photons, each traveling at the same wavelength and in the same direction. Laser light deposits large amounts of energy in a very small area; in most of today's commercial lasers, this causes extremely rapid, localized heating that cuts a material by melting or even evaporating it, Li says. But when he tried cutting through thin slabs of Cheddar with a traditional laser, the cheese did what you might expect: It cooked.

Li turned next to relatively new lasers that emit light in the ultraviolet (UV) range. Unlike conventional lasers, which produce light of longer wavelengths and cut purely by heating, higher-energy UV lasers cut through in a process called photoablation. This occurs when a laser produces photons whose energy exceeds the bonds holding molecules together, so that a photon striking one of these bonds immediately breaks it. The millions of photons emitted by a UV laser smash all the bonds in a material, obliterating it molecule by molecule with little or no heating. The technique is currently being patented.


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Date last modified: Thursday, 17-Feb-2005 14:09:29 CST
Date created: 17-Feb-2005