scholarly journals Study on GPF regeneration factors and extreme environmental regeneration methods

2021 ◽  
Vol 268 ◽  
pp. 01001
Author(s):  
Long Chen ◽  
Yongsheng Long ◽  
Hanyun Tuo ◽  
Rui Xu
Keyword(s):  
Low Temperature ◽  
Influencing Factors ◽  
Particulate Filter ◽  
Mathematical Methods ◽  
Gasoline Engines ◽  
Driving Mode ◽  
Particulate Filters ◽  
Soot Mass ◽  
Control Scheme ◽  
Soot Loading

In order to cope with the increasingly stringent environmental pollution control target, DI gasoline engines must use particulate filters. In order to ensure that GPF will not block or burn during the process of capturing particulate, the gasoline particulate filter (GPF) needs to be controlled based on current soot mass in real time. The loading capacity controls the regeneration of GPF, and the influencing factors of the regeneration efficiency are highly related to the GPF inner temperature, the amount of oxygen, and the soot loading of the GPF carrier. This paper analyzes the weight of the influencing factors of each consumption rate through mathematical methods, and from real test, it can be seen that there is difficult on regeneration of accumulated soot in low-temperature environments on under floor GPF. In this paper, in the test and inspection of low temperature environment, considering the drivability, the regeneration control scheme is clarified by optimizing the active control, and at the same time, the driving mode of extreme conditions is also required.

Experimental study of lubricant-derived ash effects on diesel particulate filter performance

2019 ◽  
pp. 146808741987457 ◽  
Author(s):  
Jun Zhang ◽  
Yanfei Li ◽  
Victor W Wong ◽  
Shijin Shuai ◽  
Jinzhu Qi ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Diesel Particulate Filter ◽  
Particulate Filter ◽  
Maximum Temperature ◽  
Particle Emissions ◽  
Diesel Particulate ◽  
Particulate Filters ◽  
Filter Performance ◽  
Soot Loading ◽  
Active Regeneration

Diesel particulate filters are indispensable for diesel engines to meet the increasingly stringent emission regulations. A large amount of ash would accumulate in the diesel particulate filter over time, which would significantly affect the diesel particulate filter performance. In this work, the lubricant-derived ash effects on diesel particulate filter pressure drop, diesel particulate filter filtration performance, diesel particulate filter temperature field during active regeneration, and diesel particulate filter downstream emissions during active regeneration were studied on an engine test bench. The test results show that the ash accumulated in the diesel particulate filter would decrease the diesel particulate filter pressure drop due to the “membrane effect” when the diesel particulate filter ash loading is lower than about 10 g/L, beyond which the diesel particulate filter pressure drop would be increased due to the reduction of diesel particulate filter effective volume. The ash loaded in the diesel particulate filter could significantly improve the diesel particulate filter filtration efficiency because it would fill the pores of diesel particulate filter wall. The diesel particulate filter peak temperature during active regeneration is consistent with the diesel particulate filter initial actual soot loading density prior to regeneration at various diesel particulate filter ash loading levels, while the diesel particulate filter maximum temperature gradient would increase with the diesel particulate filter ash loading increase, whether the diesel particulate filter is regenerated at the same soot loading level or the same diesel particulate filter pressure drop level. The ash accumulation in the diesel particulate filter shows little effects on diesel particulate filter downstream CO, total hydrocarbons, N2O emissions, and NO2/NO x ratio during active regeneration. However, a small amount of SO2 emissions was observed when the diesel particulate filter ash loading is higher than 10 g/L. The ash accumulated in the diesel particulate filter would increase the diesel particulate filter downstream sub-23 nm particle emissions but decrease larger particle emissions during active regeneration.

scholarly journals The effect of soot on ammonium nitrate species and NO 2 selective catalytic reduction over Cu–zeolite catalyst-coated particulate filter

2016 ◽  
Vol 374 (2061) ◽  
pp. 20150086 ◽  
Author(s):  
Oana Mihai ◽  
Stefanie Tamm ◽  
Marie Stenfeldt ◽  
Louise Olsson
Keyword(s):  
Low Temperature ◽  
Ammonium Nitrate ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Particulate Filter ◽  
Copper Species ◽  
Ammonia Storage ◽  
Electron Microscopy Analysis ◽  
Soot Loading ◽  
Nitrate Species

A selective catalytic reduction (SCR)-coated particulate filter was evaluated by means of dynamic tests performed using NH 3 , NO 2 , O 2 and H 2 O. The reactions were examined both prior to and after soot removal in order to study the effect of soot on ammonium nitrate formation and decomposition, ammonia storage and NO 2 SCR. A slightly larger ammonia storage capacity was observed when soot was present in the sample, which indicated that small amounts of ammonia can adsorb on the soot. Feeding of NO 2 and NH 3 in the presence of O 2 and H 2 O at low temperature (150, 175 and 200°C) leads to a large formation of ammonium nitrate species and during the subsequent temperature ramp using H 2 O and argon, a production of nitrous oxides was observed. The N 2 O formation is often related to ammonium nitrate decomposition, and our results showed that the N 2 O formation was clearly decreased by the presence of soot. We therefore propose that in the presence of soot, there are fewer ammonium nitrate species on the surface due to the interactions with the soot. Indeed, we do observe CO 2 production during the reaction conditions also at 150°C, which shows that there is a reaction with these species and soot. In addition, the conversion of NO x due to NO 2 SCR was significantly enhanced in the presence of soot; we attribute this to the smaller amount of ammonium nitrate species present in the experiments where soot is available since it is well known that ammonium nitrate formation is a major problem at low temperature due to the blocking of the catalytic sites. Further, a scanning electron microscopy analysis of the soot particles shows that they are about 30–40 nm and are therefore too large to enter the pores of the zeolites. There are likely Cu x O y or other copper species available on the outside of the zeolite crystallites, which could have been enhanced due to the hydrothermal treatment at 850°C of the SCR-coated filter prior to the soot loading. We therefore propose that soot is interacting with the ammonium nitrate species on the Cu x O y or other copper species on the surface of the zeolite particles, which reduces the ammonium nitrate blocking of the catalyst and thereby results in higher NO 2 SCR activity.

Simulating Area Conservation and the Gas-Wall Interface for One-Dimensional Based Diesel Particulate Filter Models

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Christopher Depcik ◽  
Dennis Assanis
Keyword(s):  
Classical Model ◽  
Particulate Filter ◽  
Gas Temperature ◽  
Flow Area ◽  
Diesel Particulate ◽  
One Dimensional ◽  
Flow Equations ◽  
Particulate Filters ◽  
Soot Loading ◽  
Physical Phenomena

Researchers have been using one-dimensional based models of diesel particulate filters (DPFs) for over two decades with good success in comparison to measured experimental data. Recent efforts in literature have expanded the classical model to account for the effects of varying soot layer thickness on the flow area of the gases. However, some discrepancies exist with respect to this formulation and the physical phenomena modeled in the channel equations. In addition, there is still some discussion regarding the calculation of the gas temperature within the soot and wall layers. As a result, this paper presents a model to discuss these different phenomena to remove or validate previous assumptions. In specific, formulation of the flow equations in area-conserved format (or quasi-one-dimensional) allows the model to account for the changes in the gaseous area as a function of soot loading. In addition, imposing thermodynamic equilibrium at the interface of the channels and wall layers allows the model to capture the thermal entrance lengths. These tasks were undertaken to illustrate whether or not the results justify the effort is worthwhile and this additional complexity needs to be incorporated within the model. By utilizing linear density interpolation in the wall to increase the computational efficiency of the code, it was determined that the classical model assumptions of neglecting soot thickness and gas temperature in the wall are valid within the range of typical DPF applications.

A Radical Rethink on Soot Containment from Auto-Rickshaw Exhausts

2014 ◽  
Vol 911 ◽  
pp. 383-387
Author(s):  
S. Ghosh ◽  
R.N. Shah ◽  
A. Goenka
Keyword(s):  
Particulate Filter ◽  
Exhaust Pipe ◽  
Asian Countries ◽  
Cfd Simulations ◽  
Good Efficiency ◽  
Particulate Filters ◽  
Particulate Air Pollution ◽  
The Everyday ◽  
Indian City ◽  
Natural Cycles

The auto-rickshaw has become a predictable part of the everyday lives of Indian city-dwellers. Although this popular means of public transport provides relatively discounted and efficient transportation, the auto-rickshaw is a key source of soot that causes particulate air pollution. These soot emissions infringe the natural cycles of the atmosphere other than their more overt effects on human health. Consequently, their entrapment becomes vital. Though most particulate filters provide a rather good efficiency, once clogged an undesired back pressure may lead to engine and/ or filter failure. Through this study a method is proposed to overcome such impenetrability. Once the particles are confined to narrower streams, smaller filters may be used which even if clogged will allow the easy passage of the exhaust gases out of the exhaust pipe. The most immediate outcome of this research is that the CFD simulations suggest inexpensive design alterations in the diesel particulate filter which can be fabricated easily. With government subsidies this component can be mass manufactured for use in India and other Asian countries where auto-rickshaws are widely used.

Filtration efficiency and pressure drop modelling of particulate filters with rear plug damage

2020 ◽  
pp. 146808742091667
Author(s):  
Onoufrios Haralampous ◽  
Marios Mastrokalos ◽  
Fotini Tzorbatzoglou ◽  
Chris Dritselis
Keyword(s):  
Steady State ◽  
Pressure Drop ◽  
Filtration Efficiency ◽  
Driving Cycle ◽  
Ceramic Filter ◽  
Particulate Filter ◽  
Local Pressure ◽  
Particulate Filters ◽  
Pressure Loss Coefficient ◽  
Particulate Mass

A model suitable for wall-flow particulate filters with partial rear plug damage is developed and experimentally validated in this work. A ceramic filter with 16% of the rear plugs mechanically removed is tested at steady-state conditions on the engine bench and transient driving cycle conditions on the chassis dynamometer. After decanning of the monolith, destructive analysis is conducted to identify deposit loading variations and scanning electron microscopy is used to study the deposit structures in the channels. It is shown that channels without rear plugs develop distinct deposit structures in the entry zone. Hence, a local pressure loss coefficient is applied to model the effect of entrance flow constrictions, taking also into account deposit restructuring phenomena at higher flow rates. In addition, a deep-bed filtration submodel is used to capture the effect of non-uniform wall velocities on deposit accumulation in the wall. The modified model is first fitted to the engine bench data and then validated in a wider range of conditions using the driving cycle tests. With the exception of prolonged steady-state loading conditions, good pressure drop and filtration efficiency predictions are obtained throughout the tests in conjunction with correct deposit property profiles. Notably, the cold-start worldwide harmonized light vehicles test cycle shows that the current European on-board diagnosis threshold limit for particulate mass is too relaxed to trigger a malfunction indication for moderate filter faults. In conclusion, the model can be applied in damaged particulate filter studies for the assessment of leaked particulate mass, the specification of more effective legislation limits and the development of rigorous on-board diagnosis systems and algorithms.

scholarly journals Late Fuel Post-Injection Influence on the Dynamics and Efficiency of Wall-Flow Particulate Filters Regeneration

2019 ◽  
Vol 9 (24) ◽  
pp. 5384 ◽  
Author(s):  
José Ramón Serrano ◽  
Pedro Piqueras ◽  
Joaquín de la Morena ◽  
Enrique José Sanchis
Keyword(s):  
Fuel Consumption ◽  
Particulate Filter ◽  
Exhaust Gas ◽  
Post Injection ◽  
Gas Temperature ◽  
Diesel Particulate ◽  
Particulate Filters ◽  
Exhaust Temperature ◽  
Injection Parameters ◽  
Wall Flow

Late fuel post-injections are the most usual strategy to reach high exhaust temperature for the active regeneration of diesel particulate filters. However, it is important to optimise these strategies in order to mitigate their negative effect on the engine fuel consumption. This work aims at understanding the influence of the post-injection parameters, such as its start of injection and its fuel quantity, on the duration of the regeneration event and the fuel consumption along it. For this purpose, a set of computational models are employed to figure out in a holistic way the involved phenomena in the interaction between the engine and the exhaust gas aftertreatment system. Firstly, an engine model is implemented to evaluate the effect of the late fuel post-injection pattern on the gas properties at the exhaust aftertreatment system inlet in different steady-state operating conditions. These are selected to provide representative boundary conditions of the exhaust gas flow concerning dwell time, exhaust temperature and O 2 concentration. In this way, the results are later applied to the analysis of the diesel oxidation catalyst and wall-flow particulate filter responses. The dependence of the diesel particulate filter (DPF) inlet temperature is discussed based on the efficiency of each post-injection strategy to increase the exhaust gas temperature. Next, the influence on the dynamics of the regeneration of the post-injection parameters through the change in gas temperature and O 2 concentration is finally studied distinguishing the pre-heating, maximum reactivity and late soot oxidation stages as well as the required fuel consumption to complete the regeneration process.

Effect of engine operating conditions on soot layer permeability and density in diesel particulate filters

2019 ◽  
Vol 22 (1) ◽  
pp. 50-63
Author(s):  
Christian Zöllner ◽  
Onoufrios Haralampous ◽  
Dieter Brüggemann
Keyword(s):  
Flow Rate ◽  
Large Particle ◽  
Operating Conditions ◽  
Particulate Filter ◽  
Diesel Particulate ◽  
Agglomerate Size ◽  
Diesel Particulate Filters ◽  
Particulate Filters ◽  
Operating Points ◽  
Particle Agglomerate

Understanding the variation of soot deposit properties in diesel particulate filters is necessary for their real-life modeling and onboard control. In this study, the effect of exhaust mass flow rate and particle agglomerate size on the soot layer permeability and density was investigated experimentally and analyzed using a well-validated model. A bare and a coated diesel particulate filter were loaded at five different engine operating points, specially selected to explore these effects in a heavily used part of the diesel engine map. Particle emissions were characterized in terms of particle agglomerate size distribution and primary particle diameter, while soot layer permeability and density were estimated indirectly by fitting the model to the pressure drop recordings. To this end, an automatic calibration procedure was applied to obtain values in a consistent and repeatable manner. The results showed considerable variation in both permeability and density. Furthermore, some trends could be identified after depicting the particle characterization data and soot layer properties in contour plots. Increased permeability appeared at the engine operating point with high flow rate and large particle agglomerate size. Lower density was obtained at the operating points with large particle agglomerate diameter.

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