Urea concentration deterioration detection in BSVI engines is vital for maintaining compliance with emission regulations. This paper introduces a groundbreaking desensorization method, which offers numerous benefits in detecting urea concentration deterioration by estimating the drop in catalyst conversion efficiency.
Traditionally, urea quality sensors have been employed to measure the absolute concentration of urea in the aqueous solution (Diesel Exhaust Fluid – DEF). This information is used to detect usage of poor quality DEF. However, desensorization eliminates the need for dedicated sensors, reducing complexity, cost, and potential sensor-related errors.
The proposed method leverages the strong relationship between catalyst conversion efficiency and urea concentration. By monitoring catalyst inlet and outlet NOx values using NOx sensors, the efficiency of the catalyst can be estimated. This estimation allows for the detection of urea concentration deterioration, ensuring that NOx emissions remain within the legal limit of 460 mg/kWhr.
Desensorization brings several benefits to the urea concentration detection process. Firstly, it eliminates the reliance on specific urea quality sensors, simplifying the system architecture and reducing maintenance requirements. This reduction in complexity leads to cost savings during production and operation.
Secondly, desensorization enhances robustness in estimating catalyst efficiency by introducing intentional variations in engine operating conditions. This validation approach ensures accurate detection by creating larger efficiency differences between good and bad urea samples. By intentionally altering engine-out NOx levels and increasing dosing quantity, the method validates the catalyst's ability to handle varying urea concentrations and provides insights into the limitations of diluted urea solutions.
Furthermore, desensorization offers improved monitoring accuracy by considering multiple conditions such as tank refill, exhaust temperature, urea quantity consumed, engine and tailpipe NOx values, exhaust mass flow, and Ammonia to NOx ratio (ANR). This comprehensive approach minimizes false detections and provides reliable indications of urea concentration deterioration.
In summary, desensorization presents a novel and beneficial method for detecting urea concentration deterioration in BSVI engines. By leveraging catalyst conversion efficiency estimation and considering various conditions, it eliminates the need for dedicated urea quality sensors, reduces system complexity and cost, and enhances detection accuracy. This innovation contributes to improved emissions control and regulatory compliance in the automotive industry.