Insulated catalyst with heat storage for real-world vehicle emissions reduction

Abstract

In previous publications, the model development and simulation of a vacuum-insulated catalytic converter was presented. GT-Suite model simulations demonstrated the heat retention capacity of the converter and corresponding emissions reductions. This article provides an update of the converter model development and analysis of real-world benefits of the converter. The vehicle-aftertreatment model of the vacuum-insulated catalytic converter was improved significantly, and detailed explanations of all theoretical modeling considerations are presented. In the absence of experimental data, a flow test experiment was conducted to measure the flow rate in exhaust tailpipe during vehicle soak due to thermosiphon. These results were used as inputs in the GT-Suite model simulations of conventional and hybrid electric vehicles. New model simulations demonstrated the ability of the vacuum-insulated catalytic converter to achieve significant emissions reductions following vehicle soaks of up to 18 h. To examine the real-world benefits of the converter, driving data were obtained from the National Renewable Energy Laboratory, and a MATLAB code was developed to statistically analyze 23,156 drive cycles. The vacuum-insulated catalytic converter was simulated on standard drive cycles to develop a correlation between melt time of the phase-change material and average drive cycle speed and acceleration. This correlation was used to predict the probability that the phase-change material will melt in a given real-world driving cycle. The MATLAB code was also used to calculate the soak time and re-solidification time probability. Finally, Federal Test Procedure emission results were weighted with the soak time probabilities. This analysis showed that in real-world driving conditions, the vacuum-insulated catalytic converter is expected to reduce cold-start CO and hydrocarbon emissions by 26% and 48%, respectively.

A Review of Thermal Energy Management of Diesel Exhaust after-Treatment Systems Technology and Efficiency Enhancement Approaches

“…The exhaust gas temperature slightly increased, and the fuel consumption decreased by 0.5% under the WLTC. Rohil et al [146] simulated a vacuum-insulated catalytic converter. CO and HC emissions decreased by 26% and 48%, respectively, at real-world driving conditions.…”

EGR Transient Operations in Highly Dynamic Driving Cycles

“…Retrospectively, the emissions strategies designed for steady state conditions are very much needed to be modified to cope up with the emissions. Various studies have been carried out to see the effect of emissions during new dynamic cycles based on cold intake conditions (J. M. Luján, Climent, Ruiz, & Moratal, 2018), heated aftertreatment system (Daya, Hoard, Chanda, & Singh, 2017). The transient operations who are responsible for NOx emission (Giakoumis, Rakopoulos, Dimaratos, & Rakopoulos, 2012;Yamada et al, 2011) are studied specifically with fast emission measurement systems (FCP Leach, Davy, & Peckham, 2019).…”