Diesel eission fluid quality detection system and method

An exhaust treatment system for treating a flow of exhaust produced by an engine comprising:

• a selective catalyst reduction (SCR) unit;
• a reducing agent dispensing unit configured to introduce a reducing agent into the exhaust;
• a first NOX sensor configured to indicate a NOX emission level of the exhaust at a location upstream of the SCR unit;
• a second NOX sensor configured to indicate a NOX emission level of the exhaust at a location downstream of the SCR unit;
• a first temperature sensor configured to indicate a temperature of the exhaust at a location upstream of where the reducing agent is introduced into the exhaust;
• a second temperature sensor configured to indicate a temperature of the exhaust at a location downstream of where the reducing agent is introduced into the exhaust and upstream of the SCR unit;
• and
• a controller configured to electronically communicate with the first NOX sensor, the second NOX sensor, the first temperature sensor, and the second temperature sensor, and to determine a reductant quality indicator according to a NOX differential between the first NOX sensor and the second NOX sensor relative to a predicted NOX differential and a temperature differential between the first temperature sensor and the second temperature sensor relative to a predicted temperature differential.