The potential for advanced ceramics in automotive engine applications

Abstract

Although the progress in industrial application of structural ceramics was over-forecast in the last decade, the materials appear to be on the cusp of application in certain automotive components. This article reports on a study of the economics of replacing certain metallic automobile valve-train components with ceramic components. Because of the costs of the materials and the associated processes, ceramic parts are most competitive in new designs and when used as valve-train systems.

Technical Cost Framework for High‐Temperature Manufacturing of Small Components and Devices

“…(2) and (3)) contains nine different parameters that all interrelate. The challenge in formulating and implementing the model is to define relations between these parameters and the variables.…”

“…That is, first-order scaling relations are developed by inputting these parameters into Eqs. (2) and (3), subject to processes that operate predominantly in steady-state, with time-invariant, uniform temperatures in the hot zone. Subsequently, the crucially important effects of heat-up transients are incorporated.…”

“…Important questions must be addressed. Among the most obvious are: furnace wall temperature T Q temperature at which isothermal cycle time to reach X ‫ס‬ 0.9 is t Q T R furnace ''rating'' temperature (Table I) Ṫ heating rate V p part volume X relative magnitude of physical property (ranges from 0 to 1) X 0 initial value of X X min minimum value of X according to product specifications ⌬X max maximum range in X according to product specifications X max X min + ⌬X max , maximum value of X according to product specifications Y process yield (ranges from 0 to 1) $ cost per part $ m contribution to $ from raw-material price $ 1 contribution to $ from power use $ 2 contribution to $ from furnace acquisition $ 3 contribution to $ from replacement of furnace constituents $ F cost coefficient for furnace acquisition $ H cost coefficient for heating-element replacement $ MU cost coefficient for muffle $ s cost coefficient for support structure ⌬$ manufacturing cost per part: $ 1 + $ 2 + $ 3 ␣ cooling time proportionality constant (∼1) ␤ rating temperature exponent (∼2) ␥ strain rate ␥ 0 reference strain rate (3 × 10 −6 /s) 12 ␦ I insulation thickness ␦* critical creep displacement for short circuiting emissivity u cost of electricity furnace capacity fraction thermal conductivity I for furnace insulation o effective for furnace hot zone A for AlN product ⌳ R 2 /at s density Stephan-Boltzmann constant stress 0 reference stress for creep (1 MPa) coefficient related to number of radiation shields annual production (i) Should continuous or batch processes be used? (ii) What furnace construction should be used?…”

Evaluation of Silicon‐Nitride Ceramic Valves

“…Advanced ceramics may also become necessary for new engine systems that require the use of light‐weight components in higher temperatures to achieve further engine efficiency and emission reduction to meet ever‐stringent environmental regulations. However, several barriers exist for the wide use of ceramics; the two major barriers are cost and reliability 1–4,12,13 . During the last few decades, considerable research has been directed toward addressing these and other barriers.…”

Modelización técnico-económica de un sistema de moldeo de aluminio a alta presión para fabricación de piezas de automoción

“…En particular, los modelos técnico-económicos, se presentan como una de las metodologías más adecuadas para analizar aspectos de los sistemas materiales, tales como la competitividad entre distintas tecnologías de procesamiento, el impacto de la introducción de una nueva tecnología o el estudio de fenómenos de sustitución de materiales (2)(3)(4)(5).…”