Abstract
This study involved conducting an experimental and numerical investigation on the effects of the air-to-fuel ratio (AFR), engine speed, and engine load on the inlet gas component of a three-way catalyst (TWC) and on the effects of noble metal loading, noble metal ratio, and carrier pore density on the emission conversion efficiency. The results showed that AFR can significantly affect the raw emissions of NOx and total hydrocarbon (THC), and better emission conversion efficiency of a TWC can be reached when AFR is controlled between 0.995 to 1. Compared with engine speed, engine load has a relatively small effect on exhaust temperature but greatly affects the flow velocity and NOx and THC emissions. Increasing the content of Pt in the catalyst can improve the THC conversion efficiency. For low Pt and Pd-Rh catalysts, the THC conversion effect is significantly deteriorated. The content of Rh affects the NOx conversion, and NOx conversion efficiency at high speeds is significantly reduced when Rh content is reduced. Higher carrier pore density can slightly improve the catalytic reaction rate and emission conversion efficiency at high engine speeds. However, high conversion efficiency can be maintained even after aging.
Highlights
Due to stringent emissions regulations and the high cost of diesel fuel, alternative fuels provide solutions to an array of environmental and economic problems
This paper aims to reveal the effects of air-to-fuel ratio (AFR), engine speed, and engine load on the inlet gas component of three-way catalyst (TWC) as well as the effects of noble metal loading, noble metal ratio, and carrier pore density on the conversion efficiency of nitrogen oxides (NOx) and total hydrocarbon (THC) to provide TWC optimization guidelines for natural gas engines
This study investigated the effect of operating conditions on TWC inlet parameters, and the influence of TWC parameters on catalytic performance of natural gas engine exhaust
Summary
Due to stringent emissions regulations and the high cost of diesel fuel, alternative fuels provide solutions to an array of environmental and economic problems. Natural gas is regarded as the most promising for internal combustion engine [1,2,3,4]. Natural gas (NG) shows many advantages as motor fuel. A higher-octane number leads to a lower tendency to knock and makes it easier to achieve a higher compression ratio and, better thermal efficiency. Natural gas is volatile, and it has a higher spontaneous combustion temperature and flammable limit. Natural gas has a lower carbon content, and as motor fuel, its CO2 emissions are lower compared with gasoline and diesel [5,6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
