Development and Validation of a Vibration-Based Virtual Sensor for Real-Time Monitoring NOx Emissions of a Diesel Engine

Abstract

With a strong legal basis and regulatory authority, cost-effective transient emission sensors that reflect real-driving emissions are key factors for accomplishing environmental requirements. It is difficult for the existing NOx emission monitoring techniques to achieve a balance between accuracy and timeliness. Fundamentally, in-cylinder combustion is the thermodynamic cause of NOx emissions and the main excitation source for engine vibration and noise emissions. A novel vibration-based virtual NOx sensor is developed based on these critical relationships for real-time NOx monitoring. First, the correlation between vibration and NOx emission was characterized in-depth. Then, a technique of constructing two-dimensional filters for vibration signals is proposed to extract combustion-related information. A principal component regression (PCR) model for NOx prediction was established based on the reconstructed in-cylinder pressure. Finally, the virtual NOx sensor is tested and validated on a single-cylinder diesel engine bench. The virtual NOx sensor is proven to meet the accuracy requirement of vehicle emission monitoring for both steady-state and transient conditions and has a better frequency response compared to the emission measurement system.

Enabling Artificial Intelligent Virtual Sensors in an IoT Environment

“…The relations can be based on physical laws, expert knowledge, or a model that recognizes data patterns. Specifically, the mechanism-based [ 26 ] virtual sensors are constructed based on the behavior of the operating mechanisms to be measured, describing the essential physical correspondence between the input and output quantities. The knowledge-based sensors [ 27 ] use the knowledge of experts who explicitly define the equations or rules between the input values and the sensor output.…”

Vibration Velocity Prediction with Regression and Forecasting Techniques for Axial Piston Pump

“…In the article, the authors set warning threshold of RMS of vibration acceleration at 5 cm s 2 . In many industrial implementations, the application of a threshold on measurements may be not enough in processes that work at different operating points [20]. Significant process nonlinearities make handmade determination of threshold values related to specific operating points difficult-that is where neural networks come into play.…”

“…For particular cases, a virtual sensor is designed to determine vibration-related quantities. As presented in [20], virtual vibration sensors could be implemented for the purpose of real-time monitoring of NO x emissions of a diesel engine. In the aviation industry, the application of a virtual vibration sensor in the context of fatigue life estimation was shown in [28].…”

Combustion Parametric Investigations of Methanol-Based RCCI Internal Combustion Engine and Comparison with the Conventional Dual Fuel Mode

“…The autoignition of the high reactivity fuel (HRF) initiates the combustion while a rise in the temperature and pressure facilitates the burning of the low reactivity fuel (LRF) (Benajes, et al, 2014). The RCCI combustion concept has turned out to be a promising model for the upcoming progeny of internal combustion engines but is still subject to an in-depth study for its perfection (Dalha, et al, 2018;Iqbal, et al, 2022). Among the Low-Temperature Combustion (LTC) concepts aimed to reduce NOx and soot emissions, such as Homogeneous Charge Compression Ignition (HCCI) or Premixed Charge Compression Ignition (PCCI), the Reactivity Controlled Compression Ignition (RCCI) combustion has demonstrated great potential.…”