Abstract: A dosing control system for an exhaust system of an engine includes: a tank containing a reductant solution having urea; an injector operable to inject the reductant solution into an exhaust flow upstream of an SCR apparatus; first and second NOx sensors disposed to sense NOx emissions in the exhaust flow upstream and downstream, respectively, of the SCR apparatus; and a control module. The control module is disposed in signal communication with the first and second NOx sensors and in operable communication with the injector, the control module being operable to set an original dosing level and decrease a dosing of the reductant solution injected by the injector based on a determination from signals received from the first and second NOx sensors that a reduction in a conversion efficiency of the SCR apparatus below a defined level of conversion efficiency has occurred.

Abstract: A dosing control system for an exhaust system includes: a reductant fluid tank operable to contain a reductant solution comprising urea; an injector disposed in operable communication between a reductant tank and an SCR apparatus, the injector being operable to inject the reductant solution from the reductant tank into a flow of exhaust upstream of the SCR apparatus; a urea quality sensor (UQS) configured and disposed to sense a concentration of the urea in the reductant solution; and, a control module disposed in signal communication with the UQS and in operable communication with the injector, the control module being operable to adjust a dosing of the reductant solution injected by the injector based on a concentration of the urea in the reductant solution.

Abstract: A dosing control system for an exhaust system includes: a reductant fluid tank operable to contain a reductant solution comprising urea; an injector disposed in operable communication between a reductant tank and an SCR apparatus, the injector being operable to inject the reductant solution from the reductant tank into a flow of exhaust upstream of the SCR apparatus; a urea quality sensor (UQS) configured and disposed to sense a concentration of the urea in the reductant solution; and, a control module disposed in signal communication with the UQS and in operable communication with the injector, the control module being operable to adjust a dosing of the reductant solution injected by the injector based on a concentration of the urea in the reductant solution.

Abstract: A dosing control system for an exhaust system of an engine includes: a tank containing a reductant solution having urea; an injector operable to inject the reductant solution into an exhaust flow upstream of an SCR apparatus; first and second NOx sensors disposed to sense NOx emissions in the exhaust flow upstream and downstream, respectively, of the SCR apparatus; and a control module. The control module is disposed in signal communication with the first and second NOx sensors and in operable communication with the injector, the control module being operable to set an original dosing level and decrease a dosing of the reductant solution injected by the injector based on a determination from signals received from the first and second NOx sensors that a reduction in a conversion efficiency of the SCR apparatus below a defined level of conversion efficiency has occurred.

Abstract: A gaseous sample for mass spectroscopy analysis is introduced into an ion resonance cell within an evacuated chamber. An electron beam is passed through the cell to ionize the gas. A magnetic field is applied along a first direction within the cell and a static electric field is applied along a second direction orthogonal to the first direction. The combined action of the magnetic and static electric fields confine the ions and cause them to orbit. An alternating electric field is created within the cell to excite ions having mass-to-charge ratios within a predetermined range. A time domain signal produced by the excited ions is detected and digitized. The digital samples of the time domain electical signal are transformed into frequency domain data by linear prediction using a linear lest-squares procedure. The resultant frequency domain data contains information about the mass of the different types of ions present in the cell and the relative number of each type.