scholarly journals Catalytic Materials for Gasoline Particulate Filters Soot Oxidation

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 890
Author(s):  
Roberto Matarrese

The energy efficiency of Gasoline Direct Injection (GDI) engines is leading to a continuous increase in GDI engine vehicle population. Consequently, their particulate matter (soot) emissions are also becoming a matter of concern. As required for diesel engines, to meet the limits set by regulations, catalyzed particulate filters are considered as an effective solution through which soot could be trapped and burnt out. However, in contrast to diesel application, the regeneration of gasoline particulate filters (GPF) is critical, as it occurs with almost an absence of NOx and under oxygen deficiency. Therefore, in the recent years it was of scientific interest to develop efficient soot oxidation catalysts that fit such particular gasoline operating conditions. Among them ceria- and perovskite-based formulations are emerging as the most promising materials. This overview summarizes the very recent academic contributions focusing on soot oxidation materials for GDI, in order to point out the most promising directions in this research area.

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 768
Author(s):  
Eleonora Aneggi ◽  
Alessandro Trovarelli

ZrO2 and Ce0.8Zr0.2O2 mixed oxides were prepared and tested in the oxidation of carbon soot at different oxygen partial pressures and degrees of catalyst/soot contact to investigate their activity under typical gasoline direct injection (GDI) operating conditions. Under reductive atmospheres, generation of oxygen vacancies occurs in Ce0.8Zr0.2O2, while no reduction is observed on ZrO2. Both materials can oxidize carbon under high oxygen partial pressures; however, at low oxygen partial pressures, the presence of carbon can contribute to the reduction of the catalyst and formation of oxygen vacancies, which can then be used for soot oxidation, increasing the overall performance. This mechanism is more efficient in Ce0.8Zr0.2O2 than ZrO2, and depends heavily on the interaction and the degree of contact between soot and catalyst. Thus, the ability to form oxygen vacancies at lower temperatures is particularly helpful to oxidize soot at low oxygen partial pressures, and with higher CO2 selectivity under conditions typically found in GDI engine exhaust gases.


2012 ◽  
Vol 588-589 ◽  
pp. 1598-1601 ◽  
Author(s):  
Xue Jun Li ◽  
Wei Hong ◽  
Yan Su

The gasoline direct injection (GDI) engine is a highly non-linear and a delayed system. The engine modle with time-delays is derived. The delays consist of an intake to torque production state delay and a network -induced interval delay. Base on the Liapunov-Krasovskii function, the criterion of interval delay control system is proposed, which ensure the idle speed control system is stability as well as robust. The simulation results show that the H∞ control has good robustness,which improves the stability of the idle speed of the GDI engine.


2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Nikhil Sharma ◽  
Rashmi A. Agarwal ◽  
Avinash Kumar Agarwal

Direct injection spark ignition or gasoline direct injection (GDI) engines are superior in terms of relatively higher thermal efficiency and power output compared to multipoint port fuel injection engines and direct injection diesel engines. In this study, a 500 cc single cylinder GDI engine was used for experiments. Three gasohol blends (15% (v/v) ethanol/methanol/butanol with 85% (v/v) gasoline) were chosen for this experimental study and were characterized to determine their important fuel properties. For particulate investigations, exhaust particles were collected on a quartz filter paper using a partial flow dilution tunnel. Comparative investigations for particulate mass emissions, trace metal concentrations, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) analyses, and high-resolution transmission electron microscopy (HR-TEM) imaging of the particulate samples collected from different test fuels at different engine loads were performed. For majority of the experimental conditions, gasohols showed relatively lower trace metal concentration in particulates compared to gasoline. HR-TEM images showed that higher engine loads and presence of oxygen in the test fuels increased the soot reactivity. Multicore shells like structures were visible in the HR-TEM images due to growth of nuclei, and rapid soot formation due to relatively higher temperature and pressure environment of the engine combustion chamber. Researches world-over are trying to reduce particulate emissions from GDI engines; however there is a vast research gap for such investigations related to gasohol fueled GDI engines. This paper critically assesses and highlights comparative morphological characteristics of gasohol fueled GDI engine.


2016 ◽  
Vol 166 (3) ◽  
pp. 3-8
Author(s):  
Timothy Johnson ◽  
Ameya Joshi

This paper provides a general review of light-duty (LD) and heavy-duty (HD) regulations, engine technology, and key emission control strategies. The US is placing a stronger emphasis on laboratory emissions, and the LD regulations are about an order of magnitude tighter than Euro 6, but Europe is focusing on real-world reductions. The California HD low-NOx regulation is advancing and may be proposed in 2017/18 for implementation in 2023+. The second phase of US HD greenhouse gas regulations propose another 25-30% tightening beyond Phase 1, beginning in 2021. LD and HD engine technology continues showing marked improvements in engine efficiency. LD gasoline concepts are closing the gap with diesel. HD engines are demonstrating more than 50% BTE using methods that can reasonably be commercialized. LD and HD diesel NOx technology trends are also summarized. NOx storage catalysts and SCR combinations are the lead approach to meeting the LD regulations. Numerous advanced NOx technologies are being evaluated and some promise for meeting the California HD low NOx targets. Oxidation catalysts are improved for both diesel and methane oxidation applications. Gasoline particulate filters (GPF) are the lead approach to reducing particles from gasoline direct injection (GDI) engines. They reduce PAH emissions, and catalyzed versions can be designed for low back pressure. Regeneration largely occurs during hot decelerations.


2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Chansoo Park ◽  
Motoki Ebisu ◽  
Choongsik Bae

Abstract The effects of turbocharger rotation inertia on instantaneous turbine efficiency were analyzed in a 2.0 L four-cylinder twin-scroll turbocharged gasoline direct injection (T-GDI) engine. Two turbochargers of different weights were prepared for comparison purposes: base T/C and light T/C. In order to evaluate the instantaneous efficiency of each turbocharger, a combination of engine tests and a 1D simulation was conducted. In the experiments, the instantaneous exhaust gas pressures, upstream and downstream of the turbine, were measured. The instantaneous turbocharger rotation speed was also measured. The instantaneous temperature and mass flow rate of the exhaust gas were taken from the 1D simulation results. Through a combination of measuring and simulating exhaust gas states for the turbines, the instantaneous turbine blade speed ratio (BSR), total-to-static turbine efficiency (ηts), reduced mass flow rate (φ), and reduced turbine speed (Nred) were calculated. The light T/C showed higher fluctuations in the instantaneous turbine rotation speed compared to the base T/C. This greater response from the light T/C is due to experiencing less inertia loss, this leads to higher fluctuations in the instantaneous Nred, BSR, ηts, and φ. As a result, the light T/C shows higher turbine efficiency at certain points after the start of the exhaust gas pulse cycle. This is because the greater response of the light T/C lead the operating conditions of the turbine to more efficient regions in the turbine map.


Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 678 ◽  
Author(s):  
Ricardo Suarez-Bertoa ◽  
Tero Lähde ◽  
Jelica Pavlovic ◽  
Victor Valverde ◽  
Michael Clairotte ◽  
...  

The introduction of a solid particle number limit for vehicles with gasoline direct injection (GDI) engines resulted in a lot of research and improvements in this field in the last decade. The requirement to also fulfil the limit in the recently introduced real-driving emissions (RDE) regulation led to the introduction of gasoline particulate filters (GPFs) in European vehicle models. As the pre-standardisation research was based on engines, retrofitted vehicles and prototype vehicles, there is a need to better characterise the actual emissions of GPF-equipped GDI vehicles. In the present study we investigate one of the first mass production vehicles with GPF available in the European market. Regulated and non-regulated pollutants were measured over different test cycles and ambient temperatures (23 °C and −7 °C) in the laboratory and different on-road routes driven normally or dynamically and up to 1100 m altitude. The results showed that the vehicle respected all applicable limits. However, under certain conditions high emissions of some pollutants were measured (total hydrocarbons emissions at −7 °C, high CO during dynamic RDE tests and high NOx emissions in one dynamic RDE test). The particle number emissions, even including those below 23 nm, were lower than 6 × 1010 particles/km under all laboratory test cycles and on-road routes, which are <10% of the current laboratory limit (6 × 1011 particles/km).


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2099
Author(s):  
Jian Gao ◽  
Anren Yao ◽  
Yeyi Zhang ◽  
Guofan Qu ◽  
Chunde Yao ◽  
...  

The super-knock poses new challenges for further increasing the power density of spark ignition (SI) engines. The critical factors and mechanism connecting regarding the occurrence of super-knock are still unclear. Misfire is a common phenomenon in SI engines that the mixture in cylinder is not ignited normally, which is often caused by spark plug failure. However, the effect of misfire on engine combustion has not been paid enough attention to, particularly regarding connection to super-knock. The paper presents the results of experimental investigation into the relationship between super-knock and misfires at low speed and full load conditions. In this work, a boosted gasoline direct injection (GDI) engine with an exhaust manifold integrated in the cylinder head was employed. Four piezoelectric pressure transducers were used to acquire the data of a pressure trace in cylinder. The spark plugs of four cylinders were controlled manually, of which the ignition system could be cut off as demanded. In particular, a piezoelectric pressure transducer was installed at the exhaust pipe before the turbocharger to capture the pressure traces in the exhaust pipe. The results illustrated that misfires in one cylinder would cause super-knock in the other cylinders as well as the cylinder of itself. After one cylinder misfired, the unburned mixture would burn in the exhaust pipe to produce oscillating waves. The abnormal pressure fluctuation in the exhaust pipe was strongly correlated with the occurrence of super-knock. The sharper the pressure fluctuation, the greater the intensity of knock in the power cylinder. The cylinder whose exhaust valve overlapped with the exhaust valve of the misfired cylinder was prone to super-knock.


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