Entity

Time filter

Source Type

West Lafayette, IN, United States

Dare T.,Ray W Herrick Laboratories | Woldemariam W.,Purdue University | McDaniel R.,North Central Superpave Center | Olek J.,Purdue University | Bernhard R.,University of Notre Dame
Transportation Research Record | Year: 2012

Sound absorption measurements have been used as a simple, cost-effective way of assessing pavement noise properties in the laboratory. However, tire-pavement noise (TPN) is emitted close to the pavement at shallow angles of incidence between the tire and a roadside receiver. Absorption properties can be used to predict oblique incidence noise properties, provided that certain assumptions are met. Near-grazing-incidence predictions of noise vary widely, and the assumptions involved may not be applicable to porous asphalt pavements. A method of directly measuring near-grazing-incidence noise reduction of hot-mix asphalt pavements was designed. It was found that the results of the proposed test could not be predicted from absorption data alone except for dense-graded pavement. For porous or thin, gap-graded pavements, the near-grazing-incidence test gave additional useful information about the acoustic performance of the pavement samples. The test can be used to supplement absorption and other laboratory tests for more accurate predictions of TPN. Source


Hengeveld D.W.,Load Path | Braun J.E.,Purdue University | Braun J.E.,Ray W Herrick Laboratories | Groll E.A.,Purdue University | And 2 more authors.
Journal of Spacecraft and Rockets | Year: 2011

A study was conducted to demonstrate a simplified approach for determining the optimal distribution of electronic components between various exterior spacecraft panels to achieve a more balanced distribution of heat flux. A computational tool was developed that provides rapidly optimized component distributions over multisided structures, each with unique environmental loading. Optimized, even, and worst-case distributions for 36 components in a hot-case orbit were found for total power of 100 up to 1200 W. On average, optimized component distributions reduced maximum temperatures by 5.4 K, increased minimum temperatures by 7.1 K, and reduced maximum temperature differences by 12.6 K over evenly distributed components. The largest and smallest maximum temperature difference reductions were 17.8 K at 400W and 9.5 K at 100 W, respectively. As total power increases, components were distributed in an attempt to provide equal heat flux to all faces. Consequently, more components were placed on cold faces. Source


Hengeveld D.W.,LoadPath | Braun J.E.,Purdue University | Braun J.E.,Ray W Herrick Laboratories | Groll E.A.,Purdue University | And 2 more authors.
Journal of Spacecraft and Rockets | Year: 2011

Isothermalization of satellite panels contributes positively to system thermal performance. Although technology innovations provide one solution path, an alternative method that has not received much attention is simply optimized component placement. The present approach provides a fast method for determining optimized component placement over a rectangular surface that approaches a uniform distribution of heat flux. The approach presented in this paper is especially useful in situations in which limited or no thermophysical properties and/or environmental conditions are readily available. The resulting methodology can be used in a variety of industries, including microelectronics and satellite development A companion Technical Note (Hengeveld, D., Braun, J., Groll, E., and Williams, A., "Optimal Distribution of Electronic Components to Balance Environmental Fluxes,"Journalof Spacecraft and Rockets, Vol. 484, 2011, pp. 694-697. doi: 10.2514/1.51063) addresses the problem of distributing individual components to individual panels of a satellite. When combined, the two methodologies provide an overall approach for minimizing temperature distribution across an entire satellite structure. Copyright © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Source


Pietrzak B.W.,Ray W Herrick Laboratories | Le D.,Ray W Herrick Laboratories | Shaver G.M.,Ray W Herrick Laboratories
Proceedings of the American Control Conference | Year: 2014

Fuel injection rate shaping is one path towards cleaner and more efficient diesel engines. Piezoelectrically actuated fuel injectors meet this requirement, but can exhibit improved model-based estimation performance when their internal parameters are estimated on line. To this end, this paper presents an online parameter estimation strategy for a piezoelectric fuel injector that results in improved fuel flow rate estimation when there is assumed to be some initial error in the parameter estimates. In the presence of an initial parameter error of 25%, the parameter estimator improved the model-based prediction of total injected fuel by approximately 10%. © 2014 American Automatic Control Council. Source


Kocher L.E.,Ray W Herrick Laboratories | Stricker K.,Ray W Herrick Laboratories | Van Alstine D.G.,Ray W Herrick Laboratories | Shaver G.M.,Ray W Herrick Laboratories
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2012

Advanced combustion strategies, such as pre-mixed charge compression ignition (PCCI), homogenous charge compression ignition (HCCI) and low temperature combustion (LTC), can be controlled and enabled through the use of flexible valvetrains. The in-cylinder oxygen fraction serves as a critical control input to these strategies, but is extremely difficult to measure on production engines. Fortunately, estimates or measurements of the oxygen fraction in the intake and exhaust manifold, the in-cylinder charge mass, and residual mass can be utilized to calculate the in-cylinder oxygen fraction. This paper outlines such a physically-based, generalizable strategy to estimate the in-cylinder oxygen fraction from only production viable measurements or estimates of exhaust oxygen fraction, fresh air flow, charge flow, fuel flow, turbine flow and EGR flow. The oxygen fraction estimates are compared to laboratory grade measurements available for the intake and exhaust manifolds. Furthermore, the in-cylinder oxygen estimation algorithm is developed, and proven, to be robust to turbine flow errors. The model-based observer estimates the oxygen fractions to within 0.5% O2 and is shown to have exponential convergence with a time constant less than 0.05 seconds, even with turbine flow errors of up to 25%. The observer is applicable to engines utilizing high pressure cooled exhaust gas recirculation, variable geometry turbocharging and flexible intake valve actuation. © 2012 IFAC. Source

Discover hidden collaborations