Energy-efficient heating strategies of diesel oxidation catalyst for low emissions vehicles

Abstract

Electrically heated catalyst (EHC) is integrated with the exhaust aftertreatment system to reduce cold-start emissions. Implementation of this proposed emission control technology will also provide addition CO2 and fuel consumption benefits. Developing an energy-efficient heating strategy has shown a significant reduction in the time required for the catalysts to light-off from the cold-start. In this study, it was found for the first time that the novel pulsating heating strategy with the pulse width of 30 s compared with typical heating strategy improved the CO and THC emissions conversion efficiency up to 34% and 31%, respectively. In contrast, a further increase in the heating pulse leads to lower emissions' conversion performance due to extending heating off period and consequently leading to the catalyst's light-out. Furthermore, combined electrical and fuel post-injection catalyst heating can benefit from the EHC's quick catalyst light-off and higher heating efficiency of the fuel post-injection, which showed a significant improvement in the DOC's emissions conversion performance. This approach can result in higher catalyst heating efficiencies and lower THC emissions which can be critical to meet the emissions legislations. An increase in the DOC's outlet temperature can be also beneficial for downstream aftertreatment component heating, e.g. DPF regeneration.