Filter Regeneration Research Articles

Explainable AI Using OBDII Data for Urban Buses Maintenance Management: A Study Case About the DPF Regeneration

Industry 4.0, leveraging tools like AI and the massive generation of data, is driving a paradigm shift in maintenance management. Specifically, in the realm of Artificial Intelligence (AI), traditionally “black box” models are now being unveiled through explainable AI techniques, which provide insights into model decision-making processes. This study addresses the underutilization of these techniques alongside On-Board Diagnostics data by maintenance management teams in urban bus fleets for addressing key issues affecting vehicle reliability and maintenance needs. In the context of urban bus fleets, diesel particulate filter regeneration processes frequently operate under suboptimal conditions, accelerating engine oil degradation and increasing maintenance costs. Due to limited documentation on the control system of the filter, the maintenance team faces obstacles in proposing solutions based on a comprehensive understanding of the system’s behavior and control logic. The objective of this study is to analyze and predict the various states during the diesel particulate filter regeneration process using Machine Learning and explainable artificial intelligence techniques. The insights obtained aim to provide the maintenance team with a deeper understanding of the filter’s control logic, enabling them to develop proposals grounded in a comprehensive understanding of the system. This study employs a combination of traditional Machine Learning models, including XGBoost, LightGBM, Random Forest, and Support Vector Machine. The target variable, representing three possible regeneration states, was transformed using a one-vs-rest approach, resulting in three binary classification tasks where each target state was individually classified against all other states. Additionally, explainable AI techniques such as Shapley Additive Explanations, Partial Dependence Plots, and Individual Conditional Expectation were applied to interpret and visualize the conditions influencing each regeneration state. The results successfully associate two states with specific operating conditions and establish operational thresholds for key variables, offering practical guidelines for optimizing the regeneration process.

Differential Effects of Various Cleaning Solutions on the Cleaning and Regeneration Performance of Commonly Used Polyester Fiber Material Air Filters

The regeneration and performance of air filter materials are important means of conserving energy and reducing emissions in civil public buildings. The repeated regeneration and use of air filters can not only effectively increase the lifespan of the filters but also reduce the phenomenon of filter disposal and incineration after reaching or not reaching the replacement cycle, further reducing resource waste and air pollution and thereby directly or indirectly reducing carbon emissions. In this study, polyester fiber air filters commonly used in civil public buildings were selected as the research object, and the regeneration performance and structural parameters of water and a cleaning solution were investigated under various cleaning conditions. The results show that the filtration efficiency when cleaning with water was higher than that when cleaning with the cleaning solution. The filtration efficiency for PM10, PM2.5, and PM1.0 increased from 0.3% to 3.5%, 0.7% to 6.3%, and 0.1% to 4.6%, respectively. Water could be used twice for cleaning for PM10 and once for PM2.5, and the cleaning solution could only be used once for cleaning for PM10. The counting filtration efficiency of 0.3 to 2.5 μm particulates showed a relatively significant change. The resistance after cleaning with water was higher than that after cleaning with the cleaning solution. For the quality factor (QF) value of PM10, the cleaning solution had a slightly higher cleaning effect, while for the QF values of PM2.5 and PM1.0, water had a slightly higher cleaning effect. In practical use, it is recommended to first use a cleaning solution and then water for subsequent cleaning. This study provides data support for the use of filters to achieve the dual carbon goal.

On-road measurement of post-catalyst ammonia emissions from gasoline and hybrid vehicles using quantum cascade laser detector

Ammonia emissions from gasoline vehicles have been confirmed an essential precursor of urban secondary aerosols. To more comprehensively understand the formation mechanisms and better control vehicle-related ammonia, this paper measured the on-road ammonia emissions from six conventional and four hybrid vehicles using a state-of-the-art Quantum Cascade Laser analyzer on urban, rural, and highway routes. The test vehicles emitted 0.01 to 4.27 mg/km of ammonia emissions, with a fleet average of 1.04 mg/km. Compared to the previous laboratory tests, the results of this study were low because of the high emission standards of the vehicles and the near-zero emissions during rural driving. Most test vehicles showed high ammonia emissions during engine warm-up, while some vehicles also had ammonia peaks during dynamic highway driving. On average, hybrid vehicles emitted 60.7% less ammonia emissions than the conventional candidates. It is confirmed that ammonia was formed when incomplete oxidation products presented on a warm catalyst. Engine warm-up, dynamic highway driving, particulate filter regeneration, and hybrid engine re-starting could be important sources. It is hypothesized that the ammonia formed on the upstream catalyst could be consumed by the downstream catalyst at moderate catalyst temperature, resulting in the near-zero ammonia emissions during rural driving.

Optimal control of Hydrocarbon Reducer (HC) injection based on Trust-Region-Reflective Algorithm (TRRA) and physical models for Diesel Oxidation Catalyst (DOC)

The aim of this paper is to control the DOC outlet gas temperature between 600±15°C by optimizing the hydrocarbon (HC) injection into the Diesel Oxidation Catalyst (DOC) for active regeneration of the downstream Diesel Particulate Filter (DPF). First, based on the physical model of the DOCthermal dynamics, the energy conservation equation for the gas phase temperature is simplified by using variable substitution, and the energy conservation equation for the solid phase temperature is simplified by considering only the heat generated by the HC injection. By solving the simplified model using the Trapezoidal Rule-Backward Differentiation Formula 2 (TR-BDF2) method and optimizing the model parameters in combination with the Gauss-Newton method, the computational efficiency and accuracy were significantly improved. Next, the DOC downstream temperature observer is designed by combining the solution characteristics of the DOC model with the unscented Kalman filter (UKF) algorithm to ensure that the catalyst operates within the optimal temperature range. Then, this paper verifies the accuracy of the model and observer through bench tests covering four steady-state operation conditions and World Harmonized Transient Cycle (WHTC)test cycle, and the results show that the model and observer exhibit high accuracy in both steady-state and transient operation conditions. Finally, the DOC temperature was successfully maintained between 600±15°C by optimizing the control of the HC injectionrate, thus achieving the expected temperature control target. These research results provide theoretical and practical support for diesel engine emission control and DPF active regeneration.

Assessing Adsorption and Desorption Performance in the Recovery of Volatile Organic Compounds

In this study, the activated carbon fiber filter design and VOC adsorption and desorption performance were evaluated based on the development of a filter regeneration device to treat VOCs in high efficiency and low cost. Activated carbon fiber (ACF) has the advantage of fast adsorption speed and high adsorption capacity because micropores are formed on the surface and a large specific surface area. However, the specific gravity is about 25 times lower than that of activated carbon (AC), so the amount of adsorbent that can fill the same volume is small. In order to solve this problem, the regeneration device is implemented by repeating adsorption and regeneration for a short time, and a cylindrical adsorption filter made of activated carbon fiber is designed according to the operating conditions of the regeneration device. At this time, the pollutant gas and regenerated air are uniformly distributed over the entire adsorbent, and the flow characteristics according to the supply of the pollutant gas and the regeneration gas are analyzed. When the size of the lower part of the cylindrical adsorption filter is smaller than the size of the upper part under the condition that the pollutant gas flows downward, a uniform distribution of the pollutant gas is possible. In addition, as the space velocity decreases, the adsorption capacity decreases, and the differential pressure increases rapidly. Through the regeneration experiment, it was confirmed that the desorption concentration of MEK was higher and the desorption concentration was higher. In addition, the regenerated air is uniformly dispersed throughout the adsorption filter, toluene, o-xylene, and methyl ethyl ketone, which are representative substances of volatile organic compounds (VOCs), are injected with 400 ppm, and then regenerated air is supplied at 150 °C to analyze adsorption characteristics and regeneration concentrations. As a result of the experiment, the adsorption capacity ratio to 1 g of regeneration air according to the type of VOCs was 0.48, 0.36, and 0.25 g in the order of o-xylene, toluene, and methyl ethyl ketone. In addition, as the space velocity decreases, the adsorption capacity decreases, and the differential pressure increases rapidly. Through the regeneration experiment, it was confirmed that the desorption concentration of MEK was higher and the desorption concentration of o-xylene was discharged at a relatively low concentration. Moreover, even if the adsorption concentration changes, there was no difference in the regeneration concentration change. Therefore, the filter was designed based on the spatial speed of the regeneration device of 51,000 -h or less, and the adsorption capacity ratio to 1 g of the regeneration air amount was 0.1 g, thereby enhancing the filter's recycling performance and VOCs emission effect.

An experimental study about the characteristics of reciprocating flow regeneration of diesel particulate filter with diesel vapor injection

An experimental study about the characteristics of reciprocating flow regeneration of diesel particulate filter with diesel vapor injection

The influence of particle filter regeneration on oil consumption in euro 5 Diesel Engine

Abstract The transport sector is a significant contributor to air pollution through the concentrations of emissions contained in the road vehicles flue gases. Although the implementation of EURO standards and the use of modern de-pollution technologies have greatly contributed to the reduction of these emissions, the concentrations of pollutants in the atmosphere are still high. In this context, the paper analyses the cases in which the stability of the de-pollution system indirectly influences the oil consumption during the operation of a EURO 5 diesel engine fitted to an M1 car, which is caused by its improper operation. Thus, oil consumption is analyzed according to the degree of particulate filter blockage and its influence on engine performance. The results of the study showed that new technical solutions are needed to improve the stability of the engine operation. These solutions also lead to a reduction in the pollution generated by the car operation.

Reusability and regeneration of antibacterial filter immobilized zinc oxide nanoparticles on white silica gel beads coated with chitosan

Reusability and regeneration of antibacterial filter immobilized zinc oxide nanoparticles on white silica gel beads coated with chitosan

Real biofuel and fossil-fuel soot combustion activities in active and passive regeneration of diesel/gasoline particulate filters under different O2/NOx concentrations.

In this work, we aim to investigate and compare the combustion reactivities of real biofuel soot and fossil-fuel soot in the active and passive regeneration conditions of DPF and GPF through temperature-programmed oxidation (TPO). Higher reactivity of biofuel soot is achieved even under GPF conditions with extremely low oxygen concentration (~ 1%), which provides a great potential for low-temperature regeneration of GPF. Such a result is mainly attributed to the low graphitization and less surface C = C groups of biofuel soot. Unfortunately, the presence of high-content ashes (~ 47%) and P impurity in real biofuel soot hinder its combustion reactivity. TPO evidences that the O2/NOX-lacking conditions in GPF are key factors to impact the combustion of soot, especially fossil-fuel soot. This work provides some useful information for understanding real biofuel and fossil-fuel soot combustion in GPF and DPF regeneration and further improvement in filter regeneration process.

Co,Ce nanoparticles supported on stacked wire mesh cartridges. Activity and stability in diesel soot combustion

In this work, Co3O4 nanoparticles were successfully synthesized by precipitating a precursor salt solution in the form of microdroplets generated by a nebulizer, as an efficient, fast and low-cost approach. After drying and calcination, synthesized particles were deposited on stacked wire mesh monoliths by immersing the structures in a suspension containing synthesized Co3O4 particles and commercial ceria nanoparticles as a binder. These structured catalysts were evaluated for the combustion of diesel soot which constitutes a crucial step in the regeneration of catalytic particulate filters (CDPFs). Thermal and mechanical stability of Co,Ce washcoated monoliths were investigated. For this, successive catalytic evaluations of the structured system, with intermediate treatments at 900°C (accelerated aging), were carried out indicating a very good activity and stability of the catalysts developed. Adherence tests showed good adhesion of the catalytic layer to the metallic substrate. Fresh and aged catalysts were fully characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Laser Raman Spectroscopy (LRS) and Temperature-Programmed Reduction (TPR). It was found that the catalytic coating resulted composed of nanometric CeO2 and Co3O4 along with chromium, iron and manganese oxides coming from the migration of the metallic substrate, in the catalytic cartridge calcined at 600°C. Despite after calcination at 900°C spinels of Co, Fe, Cr and Mn were observed, these oxides did not significantly affected the catalytic activity. Although this aging treatment at 900°C was severe and is not expected under real conditions, it highlights the potential application of the catalytic metallic cartridges here developed.

Electricity-driven rapid regeneration of ceramic paper-based soot filters with conductive potassium-supported antimony-doped tin oxide catalyst

Electricity-driven rapid regeneration of ceramic paper-based soot filters with conductive potassium-supported antimony-doped tin oxide catalyst

Investigation of the impacts of regeneration temperature and methanol substitution rate on the active regeneration of diesel particulate filter in a diesel-methanol dual-fuel engine

Investigation of the impacts of regeneration temperature and methanol substitution rate on the active regeneration of diesel particulate filter in a diesel-methanol dual-fuel engine

Soot particles formed by n-heptane and n-heptane/oxymethylene ether-3 in an inverse diffusion flame: A comparative analysis of chemical features

Soot particles formed by n-heptane and n-heptane/oxymethylene ether-3 in an inverse diffusion flame: A comparative analysis of chemical features

Nonlinear model predictive control(NMPC) of diesel oxidation catalyst (DOC) outlet temperature for active regeneration of diesel particulate filter (DPF) in diesel engine

Nonlinear model predictive control(NMPC) of diesel oxidation catalyst (DOC) outlet temperature for active regeneration of diesel particulate filter (DPF) in diesel engine

Effect of non-thermal plasma injection flow rate on diesel particulate filter regeneration at room temperature

Effect of non-thermal plasma injection flow rate on diesel particulate filter regeneration at room temperature

Investigation of the physicochemical properties of soot subjected to non-catalytic and CeO2-catalytic aging under sequential aerobic and anaerobic exhaust-like conditions simulating the transition from engine operation to cessation

Investigation of the physicochemical properties of soot subjected to non-catalytic and CeO2-catalytic aging under sequential aerobic and anaerobic exhaust-like conditions simulating the transition from engine operation to cessation

A novel combined system for efficient nitrate removal using a continuous flow electrocoagulation and sand filtration (FECF) reactor: Statistical analysis by Taguchi design.

In this study, a new hybrid bench-scale electrocoagulation-sand filtration (FECF) reactor was developed for purifying nitrate-contaminated samples. Before and after electrochemical treatment, two sand filters were included in this continuous system to facilitate the purification procedure, and the contaminated water flows horizontally through the entire system according to a specific hydraulic gradient within the reactor, resulting in water purification. Significant improvement in treatment performance was observed due to the presence of metal hydroxides in the second filter media that were not fully involved in the electrocoagulation treatment. Energy dispersive X-ray (EDX) analysis was performed to detect metal hydroxide species in the sand media, and the need for filter regeneration was evaluated by monitoring changes in the system flow rate. Moreover, an evaluation of the effects of different factors including operating time, current intensity, initial pH, type of anode and cathode, initial nitrate concentration, hydraulic head level inside the reactor, number of electrodes, and NaCl electrolyte concentration on the performance of nitrate removal was conducted through the Taguchi design. Further, ANOVA analysis verified the accuracy of the predicted model, and the variables were classified based on their relative importance in the FECF process. According to the regression model, 97% of nitrates were removed with Al electrodes as anode and Fe as cathode, 70 min purification time, current intensity of 3 A, 100 mg/l initial nitrate concentration, pH 8, electrolyte concentration of 1 g/l, electrode number of 6, and 1.5 cm head level.

Modeling soot filter regeneration process through surface-reactive flow in porous media using iterative lattice Boltzmann method

Modeling soot filter regeneration process through surface-reactive flow in porous media using iterative lattice Boltzmann method

Study of possibilities of cleaning of mechanical filters of baromembrane plants

The appearance of contamination on the membrane and filters, which significantly reduces the efficiency of operation (separation efficiency, water permeate flow, salt rejection) and the service life of a reverse osmosis plant, is one of the most urgent problems that arise during water treatment using this plant. Therefore, the purpose of the work is to find optimal methods for cleaning and regeneration of mechanical filters of reverse osmosis plants. The solution to this problem is carried out by means of an empirical analysis of available scientific information and conducting laboratory studies on cartridge cleaning and infiltrate processing. A cycle of experiments on cleaning of used mechanical filters of reverse osmosis in a specially assembled plant with a gradual increase in the concentration of sulphuric acid has been conducted. According to the observations during laboratory research, effective removal of dissolved iron from the solution used to wash contaminated polystyrene filters begins at pH = 4 and up to pH = 10, but at pH = 4 the settling and filtering take 24 hours, and at pH = 10 this process takes no more than an hour. As a result of further research, the most effective hydrogen indicator for settling and almost complete removal of iron from the solution is 4.5. Further increase of the hydrogen indicator to 10 is ineffective. In addition to the chemical method of neutralising the mother solution, the use of electrodialysis is also advisable, while the use of electrolyser with a lead anode would be the best option. Thus, after cleaning of one mechanical filter, almost 80 g of pure gypsum is obtained. This gypsum can serve as a highquality cement additive or be used for the production of internal cladding plates. Clean water obtained during the process can be used for subsequent cycles of other mechanical filters cleaning

Experimental Study on a Fire Caused by Diesel Particulate Filter Regeneration

In this study, a vehicle fire caused by diesel particulate filter (DPF) regeneration in a truck was investigated and analyzed. A DPF is a filter that collects soot from the exhaust gas; when certain conditions are met, the soot collected in the DPF is burned by the high-temperature exhaust gas. This process is referred to as regeneration. During DPF regeneration, the high-temperature exhaust gas is ejected and combustibles around the exhaust outlet under the vehicle may ignite. Herein, we analyzed a case of fire that occurred in an underground parking lot in 2022. The vehicle was parked for loading, and the fire broke out approximately 6 min later. During the field investigation, traces of combustion were observed in the paper boxes stacked around the truck’s exhaust port. Thus, we conducted a DPF regeneration experiment using a vehicle similar to that which caught fire. The experimental results confirmed that the surrounding combustibles can be ignited by the high-temperature heat generated during DPF regeneration. Further analysis indicated the necessity of being aware of the risk of fire owing to DPF regeneration when vehicles are parked or stopped and combustible materials are present around the exhaust outlet.