Carrusel anterior Carrusel siguiente. Buscar dentro del documento. Feuls Mesa Ejecutiva. Arturo Quiros. Juan Mercado. Gustavo Limeta. Ivan Caro. Carlos Montelongo. Christian Norambuena Vallejos. Alexander Qvlz. Aaron Espinales. C Castro J Gabriel. Charly Harol Barrientos. Guadalupe Cuaquentzi. Kevin Quintero. Martin Montoya. Arturo Mesa Mesa. Edison Maiquiza. Erik Gonzalez. Coraima Nicole. Anderson Torres. Acquire data at P n and F Zn as prescribed in the relevant practice.
The stepwise approximation contains six or more approximately equally spaced steps. Figure A-1 is an example of such a coastdown. The first step is to apply the required data corrections. At that point the rolling resistance is computed. Since the data are taken on a 1. An approximate correction for curvature is obtained by applying the Clark equation, Equation 2. The text of J notes that the question of correction for curvature needs to be revisited; however, this has not been done since J was adopted in For modeling and other engineering purposes, empirical relationships are fit by using the J and J data.
J was not revised so that its equations are the J equation at a single velocity. In comparing tire specifications, it is important to be able to characterize tire rolling resistance with a single number. The model derived from J or J can be queried to yield a rolling resistance value at a single point. Because of the possibility of needing to produce data on a large array of tires, J contains a Simplified Standard Reference Condition, which yields data at the following single condition.
At the time this appendix was prepared, a single-point test at the Simplified Standard Reference Condition was in ballot as a revision of J J contains a method for deriving a single number representative of a known driving cycle. This is the mean equivalent rolling force MERF. It is calculated by Equation 7. Equation 7 is the time integration of the rolling resistance during the cycle under study divided by the time during which the cycle occurs.
Typically, the cycle under consideration would be one of the federal test procedure FTP driving cycles such as the urban or highway schedule. This is a MERF computed at the standard reference conditions discussed above.
This report examines the contribution of tires to vehicle fuel consumption and the prospects for improving tire energy performance without adversely affecting tire life, traction capability, and retail prices. The report reviews the technical literature and analyzes energy performance data from nearly passenger tires on the market today. National fuel savings from improving the energy efficiency of passenger tires by 10 percent are quantified and the implications for consumer spending on tires, motor vehicle safety, and scrap tire generation are considered.
Observing that consumers are given little, if any, information on the fuel economy effects of tires, the report recommends that government and industry cooperate to fill this information gap. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website. Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.
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