Technologies

Engines & Power Electronics : Testing & monitoring

Technologies

High Accuracy Angle Measuring Device for Industrial, Medical, Scientific or Recreational Use

A UW-Stout researcher has developed a high-accuracy angle measurement system that addresses the problems inherent to commercially available systems. In this novel device, a high accuracy rotary optical encoder is controlled by a microprocessor. The encoder consists of rotating optical disks and sensors that are precisely formed and placed to read angles with 0.001 arc second sensitivity (average) and better than ±0.1 arc second accuracy (single readings), which is comparable to the accuracy of the high-end commercial encoders currently on the market. This accuracy is maintained with strategies that combat the mechanical sources of error that are known disadvantages of other devices. The system can also be adjusted to compensate for any asymmetrical shifts that may occur. Mechanical sources of error and noise are further minimized by precision placement of disks and sensors, as well as low-friction reference points that keep components centered and level during rotation. In addition, multiple sensor heads eliminate major readout errors and remove the need for recalibration. All of these features and benefits are contained within a design that is both compact and portable. Beyond high accuracy and portability, the cost of this new angle measurement system is substantially lower than a high-end commercial system because it is easily constructed from readily available industrial grade components, bringing the production cost to roughly $2,000. Strikingly, this cost is comparable to the advertised price of other rotary position encoders that are less than one tenth as accurate. Its high accuracy, low cost, and portability make this new angle measurement system a strong option for use in virtually any of the current applications for absolute rotary encoders.
T130018US02

Internal Combustion Engine Exhaust Filtration Analyzer

UW-Madison researchers have developed an improved method and system for analyzing the performance of filtering materials used in DPFs and other exhaust filtration devices.  The new method is able to replicate actual in-use processes that occur during filling and regeneration of filtration devices.  The ability to accurately replicate realistic conditions and manipulate key system parameters sets the new method apart from previous techniques and allows for more accurate and complete analyses of exhaust filtration materials.

Control of the various operational parameters is provided by variable exhaust flow restriction with an actuating valve and orifice in the exhaust system.  In a diesel engine, the exhaust back pressure can be modulated to control the flow characteristics of the exhaust with an actuating value through feedback from a differential pressure sensor placed across the filtering material.  A mass flow controlled orifice may be incorporated downstream of the exhaust analyzer to control the filtration velocity independent of engine operating conditions.  The orifice also allows control of total downstream flow rate while diluting the sampled exhaust with a constant flow of air and provides a constant volume ratio of exhaust and air.  Both improve the evaluation of filter performance by reducing the number of dynamically changing parameters.  The exhaust also may be cooled in stages to control temperature-related characteristics of the exhaust, increasing the accuracy of results.

The implementation of exhaust filtration devices will continue to grow with increasing government regulation of emissions from mobile and stationary internal combustion engines.  As these regulations become more stringent and encompassing, exhaust filtration analysis will be an increasingly important tool in the filtration material development and certification of DPFs and other exhaust filtration devices.
P08173US

Non-Intrusive Monitoring of Combustion Chambers

A UW–Madison researcher has developed an improved monitoring system for engine combustion chambers that is less expensive and requires fewer components than currently available systems. Rather than using sensors located within the combustion chambers, this monitoring system makes use of a valve that allows air and fuel to enter and exit the chamber. When the piston compresses the air/gas mixture, the valve seals the chamber to contain it for the combustion process. The high pressure exerted by the piston compression causes the valve head to bend slightly, displacing the valve stem. Because the stem extends out of the chamber, displacements as small as 1/1000 of an inch can be measured by a sensor located on the outside of the chamber. To calculate pressure, the displacement is compared to a plot of valve movement versus cylinder pressure. Then a control system uses that information to adjust engine operation.
P08225US

Spectrographic Sensor for Precisely Measuring Gas Parameters in an Internal Combustion Engine

A UW-Madison researcher has developed a device capable of accurately and quantitatively measuring gas temperature and concentration within a cylinder. The device includes a fiber optic light source installed in a spark plug. The fiber optic source introduces a light signal into the combustion space within the cylinder. A high-speed spectrographic sensor, such as a spatial heterodyne spectrometer, analyzes the strength of the light after it interacts with the combustion gases. A computer can then use this information to automatically determine gas temperature and water concentration, and to measure the absorption spectra of the combustion gases.
P07135US

Internal Combustion Engine Testing with Thermal Simulation of Additional Cylinders

UW-Madison researchers have developed an apparatus to simulate heat transfer of a multiple-cylinder engine on a single-cylinder test engine. Virtual cylinders are simulated by a processor, and “loads,” or energy inputs are applied to the single-cylinder test engine to more accurately reflect its performance in a multiple-cylinder engine. Flow passages allow fluid to flow in and around the single cylinder. The temperature of the fluid is controlled by a processor to replicate the presence of heat from virtual cylinders around the single-cylinder test engine.
P06286US

Continuous-Wave Laser Source for High Speed Spectroscopy

UW-Madison researchers have devised a simple and inexpensive laser-based spectroscopy approach that is similar to FTIR in principle; however, because it has no moving parts, it offers many advantages, including the ability to produce spectra every microsecond or faster. The laser is generally fashioned as a fiber laser, which is a laser cavity composed primarily of fiber optic cable. To measure spectra, the continuous-wave fiber output is directed at the test article and onto a single photoreceiver. The photoreceiver signal is then digitally processed to produce the desired spectra.
P06122US

Control System for Internal Combustion Engines

UW-Madison researchers have developed an engine control system that models and evaluates engine states in real-time, providing more precise control over performance, especially in engines with variable valve actuation. Key to the technology is a computationally efficient thermodynamic model of a cylinder, or “virtual cylinder,” which is implemented as part of the engine’s computer system. This model estimates the mass air per cylinder (MAC) for each actual cylinder at least a fraction of an engine cycle ahead of real-time operation (generally, 0.1 to 4 cycles ahead). This, in turn, allows real-time adjustments to fuel injection and other parameters, like spark advance, offering more precise engine control. Because the virtual cylinder model estimates MAC at the cylinder itself, these estimates may be more accurate than those achieved with traditional techniques that predict MAC at the throttle. The model also accounts directly for cylinder gas dynamics, rather than indirectly through volumetric efficiency (VE) corrections and other similar techniques. Moreover, because it models cylinders individually, the virtual cylinder approach allows the each cylinder’s fuel injection and spark to be set in accordance with its own MAC estimate, rather than an average MAC value for all cylinders.
P05046US

Engine Testing Device That Simulates Dynamic Gas Exchange

UW-Madison researchers have now developed an air intake simulator that draws air from the intake manifold in a manner that simulates airflow supplying the missing cylinder(s) of a single-cylinder test engine. Thus, the device allows the single-cylinder test engine to experience the air exchange characteristics of a multi-cylinder engine.

In the system, the test engine receives air through the interior passage of an air intake adapter. Valves in the adapter separate the interior passage from a positive or negative pressure source. A processor actuates the valves, allowing air to be pulled from the passage to simulate the effect of air intake into additional virtual cylinders and/or to simulate the effect of forced air induction.
P04260US

Modeless Wavelength-Agile Laser

A UW-Madison researcher has developed an easily constructed modeless laser with a rapidly sweeping color that results in improved performance in many sensing applications. The laser changes its cavity length at a speed that prevents the formation of modes, resulting in a spectrally narrow, swept-wavelength light source that eliminates mode hopping. A pivoting mirror design provides the high rate of cavity length change.
P05034US

High-Speed, Swept Frequency Spectroscopic System

A UW-Madison researcher has developed a wavelength-agile laser capable of rapidly scanning through a broad wavelength range, with superior light coupling and reduced light loss. It is particularly well suited to measure gas absorption in engines.

The invention consists of commercially available components that include an ultra-fast laser, a non-linear optical fiber and a frequency-spreading element. When these components are connected in series, the fiber optic cable receives a multi-frequency light pulse and spreads its frequency in time prior to transmitting it into a test cell. This approach significantly reduces losses involved in coupling light to the optic fiber and avoids the measurement of unwanted nonlinear processes. By directing the laser’s output through a test article of interest, the item’s properties can be determined by the recorded transmission spectrum.
P02233US

Method and Apparatus for Simulating and Testing Internal Combustion Engines

UW-Madison researchers have developed a dynamometer for a single cylinder test engine (1CTE), which allows the 1CTE to simulate a multi-cylinder engine (MCE) by replicating its instantaneous engine dynamics. The dynamometer achieves this not only absorbing the torque output of the 1CTE (as in standard dynamometers), but also by delivering a motoring torque input to the 1CTE. Calculated in real-time by hardware and software-based methods, this input corresponds to the dynamic torque the 1CTE would receive from other cylinders if it were actually part of an MCE. Thus, the 1CTE acts dynamically as if interacting with other cylinders, allowing much more accurate simulation of MCE conditions over a wider range of speeds, including idling speeds.
P00389US