Converting Raw Thermocouple Measurements to Those Measured with a Thermocouple of a Different Size

2009-01-1113

04/20/2009

Event
SAE World Congress & Exhibition
Authors Abstract
Content
Thermocouples (TCs) are commonly used to measure exhaust gas temperature during automotive engineering experiments. To enhance the durability of TCs in the harsh exhaust gas environment, in many cases larger tip TCs (such as 1/8″ diameter) are used rather than smaller TCs. However, the signal from a larger thermocouple can differ significantly from that of small TC due to thermal capacitance of the tip, heat transfer to the exhaust pipe wall via conduction and radiation, and convection with exhaust gas. A model has been developed that calculates the effects of these factors and provides an estimate, for TCs of different sizes, of exhaust gas temperature. Experiments were performed to validate the model under transient (FTP) engine dynamometer conditions utilizing three popular TC sizes (1/32″, 1/16″, and 1/8″). Good correlation was found among predictions for various TC sizes. This analytical tool enhances the quality of exhaust gas temperature measurements and enables a useful alternative to the practice of using fragile (low durability) small tip TCs for experiments requiring accurate temperature measurements.
Meta TagsDetails
DOI
https://doi.org/10.4271/2009-01-1113
Pages
5
Citation
Son, S., "Converting Raw Thermocouple Measurements to Those Measured with a Thermocouple of a Different Size," SAE Technical Paper 2009-01-1113, 2009, https://doi.org/10.4271/2009-01-1113.
Additional Details
Publisher
Published
Apr 20, 2009
Product Code
2009-01-1113
Content Type
Technical Paper
Language
English