Real-time capable virtual NO_x sensor for diesel engines based on a two-Zone thermodynamic model

Abstract

Abstract. This paper presents a control-oriented thermodynamic model capable of predicting nitrogen oxides (NO x ) emissions in diesel engines. It is derived from zero-dimensional combustion model using in-cylinder pressure as the input. The methodology is based on a two-zone thermodynamic model which divides the combustion chamber into a burned and unburned gas zone. The original contribution of proposed method arises from: (1) application of a detailed two-zone modeling framework, developed in a way that the thermodynamic equations could be solved in a closed form without iterative procedure, which provides the basis for achieving high level of predictiveness, on the level of real-time capable models and (2) introduction of relative air-fuel ratio during combustion as a main and physically motivated calibration parameter of the NO x model. The model was calibrated and validated using data sets recorded in two different direct injection diesel engines, i.e. a light and a heavy-duty engine. The model is suitable for real-time applications since it takes less than a cycle to complete the entire closed cycle thermodynamic calculation including NO x prediction, which opens the possibility of integration in the engine control unit for closed-loop or feed-forward control.

Virtual Calibration Method for Diesel Engine by Software in The Loop Techniques

“…A fast simulation speed of the resulting models allows their implementation into real-time simulation environments, such as hardware-in-the-loop (HiL) systems [8]. The calibration of an electronic system like the one that runs a modern engine requires a thorough knowledge not only of the engine hardware itself in terms of sensors [9] and actuators, but also of the software in the control unit that, according to the calibration strategies adopted, allows the compliance with emission regulations and obtaining the desired performance in terms of power and torque supplied, as well as fuel consumption.…”

Development of a NOx Calculation Model for Low-Speed Marine Diesel Engines Based on Soft Measurement Technology

“…The mechanism-based NOx simulation model is still mainly based on the widely accepted Zeldovich mechanism as the NOx generation model. Based on constructing relevant variables, it can be divided into two categories: (1) Mathematical equations based on the working mechanism of the engine to form a more suitable NOx prediction through the appropriate simplification or additional consideration of the mixing and combustion conditions in the process of NOx formation [3][4][5][6][7][8][9][10]; and (2) use some physical signals (such as in-cylinder pressure, torque, etc.) during the working process of the engine to obtain intermediate variables through signal analysis and processing, and then combine the Zeldovich mechanism to analyze and deduce the generation of NOx to construct NOx predictive models [11][12][13][14][15].…”

Prediction of engine NOx for virtual sensor using deep neural network and genetic algorithm

“…This indicates if the engine operating conditions are adjusted through speed, torque, fuel injection, etc., the birth amount of NOx emissions changes; the optimization of NOx emission formation by engine control is possible and highly requested for a healthy driving [13,14]. In the previous studies, understanding the formation process was required to optimize the NOx emission, and researches based on the thermodynamics or Computational Fluid Dynamics (CFD) have been conducted such as the NOx emission prediction using chemical kinetics, skeletal mechanisms, 2D/3D models, and two-zone thermodynamic model [15][16][17][18][19]. They made it possible to aware of what factors influence the NOx formation and reduction.…”