Experimental study on affordable thermal insulation of exhaust manifolds using modified sheep wool waste

Abstract

Internal Combustion (I.C.) engines generate lot of heat during high-speed operations. In order to prevent this heat loss, thermal insulation is mandatory to prevent heat transfer from the exhaust to the adjacent parts. The main aim of this work is to develop a thermally insulating material placed inside the catalytic converter to block the withdrawal of heat from the converter. This insulating material is usually placed between the heat shields for better heat dissipation. Comparison studies is executed between two different types of insulation material such as conventional Z-mat and super wool at various temperatures ranging from 200 °C to 800 °C for a period of 60 min and distortion results are noted at each temperature. Muffler furnace is used for the heat treatment analysis of the fabricated super wool. The composition of the novel fabricated super wool material can withstand all temperature levels between 200 °C and 800 °C, but the conventional Z-mat is suitable only up to 600 °C, where the Z-mat structure lost its capacity of insulation. Hence, the fabricated super wool material is more suitable for insulating catalytic converters and thereby it enhances the performance of engine with longer durability. In addition, hot vibration test is conducted for a duration of 50 h to check the thermal resistance capability of the super wool material. It is found that the thermal insulation is intact in position with absence of cracks or failures, inlet face erosion and retention losses. The fabricated thermal insulation mats from sheep wool waste also passed thermal shock test performed for 1500 thermal cycles. Thereby, this sort of sheep wool based affordable thermal insulation can be used for applications associated with larger thermal gradients to control the thermal-related errors such as shrinkage, warpage and distortion, which can also be extended to acoustic absorption.