As the title states, this thread is devoted to providing links to existing research regarding DI & "soot". Focused discussion is also welcome :)
I will kick this off with a link to a presentation by Matti Maricq (Ford) on Gasoline Engines: Ultrafine Particle Emissions ----
http://www.aqmd.gov/docs/default-source/technology-research/ultrafine-particles-conference/session6_5_mattimaricq.pdf (http://www.aqmd.gov/docs/default-source/technology-research/ultrafine-particles-conference/session6_5_mattimaricq.pdf)
ZSHO provided this link related to diesel & soot:
http://www.syntheticwarehouse.com/bypass.htm (http://www.syntheticwarehouse.com/bypass.htm)
That first presentation was pretty insightful.
I'll toss this in. It is also pretty interesting...
http://www.greencarcongress.com/2009/04/developing-ecoboost-20090429.html
This article, unless I misread it, indicates the 3.5 EB specifically (and like nearly all GDI engines) only utilizes stratified lean burn at cold operation. All other conditions prompt homogeneous charges.
Though, it is described as a transient phenomenon in the first presentation in the OP. There is likely quite a bit of soot formation under the onset of high load situations.
Of course, I'm still trying to figure out how the 3.5EB operates in a closed loop control feedback at all times, save for cold start. You'd think as a result there'd be fewer soot deposits.
Even though they show a pic at 6000 rpm, the range optimized for is 1,500 to 5,500 rpm (a bit short of WOT at 6,200 rpm). But if the presentation is a good guide, always have a) a good strong battery, b) an appropriately low viscosity oil for cold start, and c) heaters for the catalysts to decrease cranking time and speed up that initial warmup nearly free of emissions.
I know on my MFI NA Edge, it takes a mere minute or less with gentle driving from initial startup to reach 1000F or so on the catalysts. Any idea how fast that happens on these EBs?
A quick primer on GDI engines:
http://www.aa1car.com/library/what_is_gasoline_direct_injection.htm (http://www.aa1car.com/library/what_is_gasoline_direct_injection.htm)
Investigations of the formation and oxidation of soot inside a direct injection spark ignition engine
http://www.sfb606.kit.edu/index.pl/Haupt_Menu_Forschungsprogramm_M08/projekte/c4/SIA_SI_engine_2009.pdf (http://www.sfb606.kit.edu/index.pl/Haupt_Menu_Forschungsprogramm_M08/projekte/c4/SIA_SI_engine_2009.pdf)
Particle Emissions from Direct Injection Gasoline Engines
http://www.swri.org/3pubs/ttoday/Summer11/PDFs/ParticleEmissions.pdf (http://www.swri.org/3pubs/ttoday/Summer11/PDFs/ParticleEmissions.pdf)
A pair of articles comparing GDI and PFI engines (deposits, fuel economy, soot, etc.) - Abstracts only:
http://papers.sae.org/1999-01-1498/ (http://papers.sae.org/1999-01-1498/)
http://papers.sae.org/1999-01-1499/ (http://papers.sae.org/1999-01-1499/)
Four 1998 Mitsubishi Carismas, two equipped with direct injection (GDI) and two with port fuel injection engines (PFI) were tested in a designed experiment to determine the effect of mileage accumulation cycle, engine type, fuel and lubricant type on engine wear and engine oil performance parameters. Fuel types were represented by an unadditised base fuel meeting EEC year 2000 specifications and the same base fuel plus synthetic deposit control additive packages. Crankcase oils were represented by two types (1) a 5W-30 API SJ/ILSAC GF-2 type engine oil and (2) a 10W-40 API SH/CF ACEA A3/ B3-96 engine oil.
The program showed that engine fuel system deposits, including specifically those on intake valves, combustion chambers and injectors are formed in higher amounts in the GDI engine than the PFI engine. The fuel additive used reduced injector deposits and combustion chamber deposits in the GDI, but had no significant effect on intake valve deposits, which are affected by crankcase oil formulation. In GDI vehicles, deposited engines were found to have increased hydrocarbon and carbon monoxide emissions and poorer fuel economy and acceleration, but lower particulate emissions. Effects in PFI engines were directionally the same for NOx and particulates but the opposite for HC and CO emissions and fuel economy. In terms of specific deposit effects in the GDI engine, CCD is correlated with poorer acceleration, HC and CO emissions, while injector deposits correlate with NOX formation.
The program showed that specific selection of oil additive chemistry may reduce formation of intake valve deposits in GDI cars.. In general, G-DI engines produced more soot and more pentane insolubles and were found to be more prone to what appears to be soot induced wear than PFI engines. Again, proper selection of oil additive chemistry provided sufficient engine durability protection in both types of engines.
A number of interesting links in this post (https://www.allpar.com/forums/threads/an-direct-injection-getting-closer.158610/page-4#post-1084654933):
"Meeting Future Global Particulate Emission Standards" (http://www.crcao.org/workshops/2014...%20Global%20Particulate%20Emission%20Standards%20v4.pdf)
JRC - "Review on engine exhaust sub-23 nm particles" (draft report) (https://www2.unece.org/wiki/downloa...%20DRAFT%20Sub23nm%20report_JRC_20140212.pdf?api=v2)
JRC - "Assessment of particle number limits for petrol vehicles" (http://publications.jrc.ec.europa.eu/repository/bitstream/JRC76849/lbna25592enn.pdf)
"Particle Emissions from Direct Injection Gasoline Engines" (http://www.swri.org/3pubs/ttoday/Summer11/PDFs/ParticleEmissions.pdf)
Advanced Particulate Filter Technologies for Direct Injection Gasoline Engine Applications
http://www1.eere.energy.gov/vehiclesandfuels/pdfs/deer_2012/wednesday/presentations/deer12_bischof.pdf (http://www1.eere.energy.gov/vehiclesandfuels/pdfs/deer_2012/wednesday/presentations/deer12_bischof.pdf)
- Continuing efforts for further CO2 and PN reduction create a challenging environment for vehicles equipped with DI gasoline engines
- Gasoline particulate filters will be an enabler to meet these challenging targets either as an alternative or as a supplement to improved combustion recipes
- Gasoline particulate filters can be designed:
– As an "add on" solution to an existing after treatment system
– As a gasoline particulate filter with integrated three way catalyst functionality
- Optimized designs for gasoline particulate filter applications
Dissertation - Effects of Fuel Molecular Structure and Composition on Soot Formation in Direct-Injection Spray Flames
http://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=1318&context=etd (http://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=1318&context=etd)
In-cylinder soot imaging and emissions of stratified combustion in a spark-ignited spray-guided direct-injection gasoline engine
http://www.scopus.com/record/display.url?eid=2-s2.0-84858215701&origin=inward&txGid=CEDEAE0A0F62CC8BEF6CE4D1D18B0D5C.fM4vPBipdL1BpirDq5Cw%3a2 (http://www.scopus.com/record/display.url?eid=2-s2.0-84858215701&origin=inward&txGid=CEDEAE0A0F62CC8BEF6CE4D1D18B0D5C.fM4vPBipdL1BpirDq5Cw%3a2)
... the engine-out soot emission measurements, which showed increased soot levels as the injection was retarded. It was also found that fuel impinged on the spark plug during the injections, resulting in a persistent jet flame close to the spark plug in the centre of the cylinder, which is believed to contribute to engine-out soot emissions ...
Numerical Investigation of Soot Formation in Gasoline Direct Injection Engines (2014)
http://www.ansys.com//staticassets/ANSYS/staticassets/resourcelibrary/presentation/aswc2014-soot-formation-direct-injection-engine.pdf (http://www.ansys.com//staticassets/ANSYS/staticassets/resourcelibrary/presentation/aswc2014-soot-formation-direct-injection-engine.pdf)
Summary
- Liquid fuel films are emitted as one of followings
– remaining fuel films
– unburned hydrocarbons
– precursors (C2H2, PAHs..)
- soot
- Emission factors of UHC and soot can be expressed as a function of the wall temperature
- A surface reaction mechanism including pyrene and coronene as precursors was constructed based on the literature
- Particle number emissions generated from combustion of liquid fuel films during cold startup period were estimated by using the method of moments
Could we be sucking in cleaner air in the cooler months with the dirty exaust vapors being warmer and their natural tendency is to rise? My simple minded thought on the absence of soot from my unchanged setup.
Rich
You are still running "enhanced" E fuel, right?
Yes sir. Eagerly awaiting summer fuel to see if dropping the e/85 has an effect.
Rich
This is why I have no soot...
https://www.ars.usda.gov/SP2UserFiles/Program/213/Teleseminars/Robert%20Stein%20%28AVL%29%203-29-11.pdf (https://www.ars.usda.gov/SP2UserFiles/Program/213/Teleseminars/Robert%20Stein%20%28AVL%29%203-29-11.pdf)
"No sooting flames with E85
•
Ethanol has a single boiling
point of 78.3°C, whereas
gasoline has a range up to
200°C. Thus E85 vaporizes
more readily after impingement
on the piston.
•
Ethanol is oxygenated which
facilitates combustion of rich
regions without making soot"
GDI engines s(n)oot-ier than diesel?
Vehicle tests show that without the use of gasoline particulate filters (GPF), more particles are emitted from gasoline direct injection (GDI) engines than diesels. On the road, GDI vehicles may therefore exceed future European emissions limits – the Euro 6 standard. The cost of a filter to eliminate particle emissions is low (around €50), with no fuel economy penalty. Despite this, carmakers are declining to fit filters to GDI cars – thereby worsening urban air pollution. T&E calls upon carmakers to ensure GDI cars minimize their particle emissions by fitting filters. Carmakers should not use unreliable 'engine management' approaches to try and control emissions, as these produce much higher numbers of particles, particularly during on-road driving.
http://www.transportenvironment.org/sites/te/files/publications/GDI%20Briefing_final_T%26E.pdf (http://www.transportenvironment.org/sites/te/files/publications/GDI%20Briefing_final_T%26E.pdf)
Delphi advancing Gasoline Direct-Injection Compression-Ignition engine concept; new two-stage supercharger/turbocharger boost system
http://www.greencarcongress.com/2013/04/gdci-20130412.html (http://www.greencarcongress.com/2013/04/gdci-20130412.html)
More efficiency, less particulate matter emission.
Experimental and Numerical Investigation of the Idle Operating Engine Condition for a GDI Engine
http://www.academia.edu/1282134/Combustion_process_analysis_for_a_GDI_engine_in_the_idle_operating_engine_condition_during_the_warm-up (http://www.academia.edu/1282134/Combustion_process_analysis_for_a_GDI_engine_in_the_idle_operating_engine_condition_during_the_warm-up)
Abstract:
The increased limitations to both NOx and soot emissions have pushed engine researchers to rediscover gasoline engines. Among the many technologies and strategies, gasoline direct injection plays a key-role for improving fuel economy and engine performance. The paper aims to investigate an extremely complex task such as the idle operating engine condition when the engine runs at very low engine speeds and low engine loads and during the warm-up. Due to the low injection pressure and to the null contribution of the turbocharger, the engine condition is far from the standard points of investigation. Taking into account the warm-up engine condition, the analyses are performed with a temperature of the coolant of 50°C.
The paper reports part of a combined numerical and experimental synergic activity aiming at the understanding of the physics of spray/wall interaction within the combustion chamber and particular care is used for air/fuel mixing and the combustion process analyses. In order to properly describe the engine condition, different injection strategies are investigated. Late and early injection strategies are deeply analyzed and compared in terms of combustion stability and pollutant emissions.
UV-visible imaging and spectral measurements are carried out in real engine with wide optical accesses... Measurements are performed in the optically accessible combustion chamber realized by modifying a real engine. The cylinder head was modified in order to allow in the fourth cylinder the visualization of the fuel injection and the combustion process with high spatial and temporal resolution.
The 3D-CFD engine simulations are reproduced by means the commercial code Star-CD. Due to the warm-up condition and the many physical sub-models a numerical methodology is implemented and particular care is used to boundaries conditions analyses. CFD analysis is used to find a possible explanation of the high cycle to cycle variability. The experimental and numerical comparisons, in terms fuel mixing and front flame propagation, give an explanation of the idle condition.
Publisher: papers.sae.org
Publication Date: Jan 1, 2012
Lean Burn Technology in GDI engines
http://www.autozine.org/technical_school/engine/petrol1.htm (http://www.autozine.org/technical_school/engine/petrol1.htm)
Lean Burn EngineBasically, engines which can operate in very lean air / fuel mixture are called "Lean Burn Engines". Japanese car makers, heading by Toyota, are the leaders in this technology.
Apparently, the leaner air / fuel mixture, the more frugal the engine is. But there are two reasons prevent conventional engines from operating in lean air / fuel mixture:
- If the mixture is too lean, the engine will fail to combust.
- Naturally, lower fuel concentration leads to less output.
Lean burn engines avoid these problems by adopting a highly efficient mixing process. They use special shape pistons, with intake manifolds located and angled matching the pistons, the intake air will generate swirl inside the combustion chamber. Swirl leads to more complete mixing of fuel and air, thus largely reduce the badly-mixed fuel particles, which will not be burnt in conventional engines. This enables more complete burning, not only reduces pollutant, but also allow the fuel / air ratio to be lowered from 1 : 14 to 1 : 25 without altering output.
Today, Lean Burn technology has evolved into Direct Injection, which is basically the former added with direct fuel injection. Toyota, Mitsubishi and Nissan all concentrate in DI engines development.
Particle and metal emissions of diesel and gasoline engines - Are particle filters appropriate measures?
http://www.exisab.com/Docs/Conferences/ETH_Nanoparticle_2012/Ulrich.pdf (http://www.exisab.com/Docs/Conferences/ETH_Nanoparticle_2012/Ulrich.pdf)
QuoteEmissions of metal oxide particles can occur for all types of internal combustion engines. Even if clean fuels are used,
lubrication oil remains as a potential source for metal oxide particles. Full-wall-flow particle filter systems have shown
high filtration efficiency in diesel exhaust gas after-treatment. However, this study demonstrated that they can be also
useful to remove metal oxide emissions from other engine types. An effective filtration of metal particles is important to
reduce toxic potential of nanosized particles and metals. Hence, filtration technology is promising not only for diesel
engines (soot filtration) but for all types of combustion engines. The filtration efficiency for metals should be further
investigated in future projects.
http://www.sciencedirect.com/science/article/pii/S0306261914002608 (http://www.sciencedirect.com/science/article/pii/S0306261914002608)
Quote
Part-load particulate matter from a GDI engine and the connection with combustion characteristics
F. Bonatestaa, E. Chiappettaa, A. La Roccab
Highlights
• Engine-out soot and combustion data are taken from a modern GDI engine at part-load.
• Greatest soot mass is emitted in the higher load-lower speed range.
• Highest soot numbers are emitted, with size 23–40 nm, in the upper part-load range.
• Soot number concentration correlates linearly with rapid burning duration.
• Soot number concentration also correlates with unburned gas temperature.
Abstract
The Gasoline Direct Injection engines are an important source of ultra-fine particulate matter. Significant research effort is still required as improved understanding of soot formation is critical in considering further development or adoption of new technologies. Experimental measurements of engine-out soot emissions have been taken from a modern Euro IV GDI engine at part-load operating conditions. The engine speed and torque were varied in the range 1600–3700 rev/min, and 30–120 Nm, respectively. The engine was invariably operated in stoichiometric and homogeneous combustion mode, with fuel injection early in the intake stroke. The results indicate that for engine load in excess of 3 bar Brake Mean Effective Pressure, due to incomplete gas-phase mixture preparation, a consistent linear correlation establishes between combustion duration and soot particle number. On average, a sixfold increase in number concentration between 1.0 and 6.0 × 106 particle per cc, arises from shortening the rapid duration of 4 crank angle degrees. For engine speed in excess of 3000 rev/min and load in excess of 7 bar BMEP, this correlation appears to be superseded by the effects of spray-to-piston impingement and consequent pool-fire. Three main areas of concern have been identified within the part-load running envelope: (1) the higher load-lower speed range and (2) the mid load-mid speed range, where high nucleation rates induce copious increases of engine-out soot mass; (3) the upper part-load range where, most likely as a result of spray impingement, high levels of soot concentration (up to 10 million particles per cc) are emitted with very small size (23–40 nm).
Keywords
Gasoline Direct Injection; Soot number density; Soot particle size; Mass Fraction Burned; Combustion duration
Corresponding author. Tel.: +44 1865485715.
Copyright © 2014 Elsevier Ltd. All rights reserved.
Ultrafine Particulate Matter and the Benefits of Reducing Particle Numbers in the United States
http://www.meca.org/resources/MECA_UFP_White_Paper_0713_Final.pdf (http://www.meca.org/resources/MECA_UFP_White_Paper_0713_Final.pdf)
Why might ethanol help reduce that visible soot on exhaust tips?
QuoteSize distribution, chemical composition and oxidation reactivity of particulate matter from gasoline direct injection (GDI) engine fueled with ethanol-gasoline fuel
Yueqi Luo, Lei Zhu, Junhua Fang, Zhuyue Zhuang, Chun Guan, Chen Xia, Xiaomin Xie, Zhen Huang
Highlights
• Ethanol-gasoline reduces elemental carbon in PM.
• Ethanol-gasoline increases volatile organic fraction in PM.
• Soot generated from ethanol-gasoline has higher oxidation activity.
Abstract
Ethanol-gasoline blended fuels have been widely applied in markets recently, as ethanol reduces life-cycle greenhouse gas emissions and improves anti-knock performance. However, its effects on particulate matter (PM) emissions from gasoline direct injection (GDI) engine still need further investigation. In this study, the effects of ethanol-gasoline blended fuels on particle size distributions, number concentrations, chemical composition and soot oxidation activity of GDI engine were investigated. It was found that ethanol-gasoline blended fuels increased the particle number concentration in low-load operating conditions. In higher load conditions, the ethanol-gasoline was effective for reducing the particle number concentration, indicating that the chemical benefits of ethanol become dominant, which could reduce soot precursors such as large n-alkanes and aromatics in gasoline. The volatile organic mass fraction in ethanol-gasoline particulates matter was higher than that in gasoline particulate matter because ethanol reduced the amount of soot precursors during combustion and thereby reduced the elemental carbon proportions in PM. Ethanol addition also increased the proportion of small particles, which confirmed the effects of ethanol on organic composition. Ethanol-gasoline reduced the concentrations of most PAH species, except those with small aromatic rings, e.g., naphthalene. Soot from ethanol-gasoline has lower activation energy of oxidation than that from gasoline. The results in this study indicate that ethanol-gasoline has positive effects on PM emissions control, as the soot oxidation activity is improved and the particle number concentrations are reduced at moderate and high engine loads.
Keywords
Gasoline direct injection (GDI) engine; Particulate matter (PM); Ethanol-gasoline; Organic compositions; Soot oxidation activity
Corresponding authors. Tel./fax: +86 21 34205949.
Copyright © 2015 Elsevier Ltd. All rights reserved.
http://www.sciencedirect.com/science/article/pii/S1359431114009909 (http://www.sciencedirect.com/science/article/pii/S1359431114009909)
QuoteInfluence of the exhaust gas turbocharger on nano-scale particulate matter emissions from a GDI spark ignition engine
Matteo Cucchi, Stephen Samuel
Highlights
• Nano-scale PM from a TGDI engine is measured with a particulate spectrometer.
• Hypothesis test proves statistically relevant differences in PM across the turbine.
• As engine load increases PM number concentrations increase across the turbine.
• Particles nucleation and agglomeration are thought to occur across the turbine.
• Hypothesis test proves turbine influence regardless of exhaust gas dilution level.
Abstract
The influence of the exhaust gas turbocharger on nano-scale Particulate Matter (PM) number emissions from a Gasoline Direct Injected (GDI) engine is investigated at fixed exhaust gas dilution ratio for a matrix of three engine speeds and four engine load operating points. Experimental repeatability is assessed by means of the Coefficient of Variation (CoV) from three independent measurements for every test point. A hypothesis test on the difference between total number count before and after the turbine shows that there are statistically relevant variations for most operating points. A reduction in PM total number count at low load is observed, and an increment at high load. It is conjectured that as fuel injection pressure and duration increase with load, a larger share of volatile particulate matter is produced, which then undergoes nucleation as the exhaust gas expands through the turbine. At the same time, the centrifugal action within the turbocharger is believed to promote particle agglomeration and growth, and fragmentation of micro-scale particles. Experiments with variable dilution ratio at a fixed engine test point show that changes in dilution ratio affect repeatability of the emissions measurements only marginally. Yet, a hypothesis test on the variation of total number count with dilution shows that PM number counts are systematically affected by changes in dilution ratio. Furthermore, a hypothesis test also shows that the impact of the turbocharger on total number emissions is statistically relevant regardless of the dilution ratio adopted.
Graphical abstract
(http://ars.els-cdn.com/content/image/1-s2.0-S1359431114009909-fx1.jpg)
Keywords
Particulate matter number emissions; Turbocharger; Gasoline direct-injection engine; Differential mobility spectrometer
Corresponding author. Faculty of Technology, Design & Environment, Department of Mechanical Engineering and Mathematical Sciences, Oxford Brookes University, Wheatley Campus, OX33 1HX, UK. Tel.: + 44 1865 483513.
Copyright © 2014 Elsevier Ltd. All rights reserved.
Page 24 gives a good visual
https://www.ars.usda.gov/SP2UserFiles/Program/213/Teleseminars/Robert%20Stein%20%28AVL%29%203-29-11.pdf (https://www.ars.usda.gov/SP2UserFiles/Program/213/Teleseminars/Robert%20Stein%20%28AVL%29%203-29-11.pdf)
Page 12 for an an extended look
http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2009/fuel_technologies/ft_12_agarwal.pdf (http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2009/fuel_technologies/ft_12_agarwal.pdf)
Deposits on fuel injectors in GDI engines, and their effects on spray patterns, wall wetting, and consequently, emissions performance
https://www.thefreelibrary.com/Injector+Fouling+and+Its+Impact+on+Engine+Emissions+and+Spray...-a0532022720 (https://www.thefreelibrary.com/Injector+Fouling+and+Its+Impact+on+Engine+Emissions+and+Spray...-a0532022720)