| 主权项 |
1. An aftertreatment system for an engine, the aftertreatment system comprising:
a selective catalytic reduction (SCR) catalyst in fluid communication with an exhaust stream generated from the engine; an oxidation catalyst (OC), upstream of the SCR catalyst and in fluid communication with the exhaust stream; a gaseous reductant injector, upstream of the SCR catalyst and downstream of the OC, and in fluid communication with the exhaust stream; a first gas sensor upstream of the OC; a second gas sensor downstream of the SCR catalyst; a controller, operatively connected to the first gas sensor, the second gas sensor and the gaseous reductant injector, wherein the controller receives signals representative of combined gas concentrations detected in the exhaust stream by the first gas sensor and the second gas sensor, estimates individual species concentrations of nitric oxide (NO) and nitrogen dioxide (NO2) in the exhaust stream according to the combined gas concentrations detected by the first gas sensor and the second gas sensor, and determines a flow rate of a gaseous reductant to be injected into the exhaust stream by the gaseous reductant injector based on the individual NO and NO2 species concentration estimates, wherein the combined gas concentrations detected by the first gas sensor and the second gas sensor each comprise a combined concentration of NO, NO2, and gases other than NO and NO2 in the exhaust stream. |
