Basic Research on Combustion Chambers for Lean Burn Gas Engines

Sakurai, Teruhiro; Iko, Masanori; Okamoto, Kazuhisa; Shoji, Fujio

doi:10.4271/932710

Cited by 16 publications

(5 citation statements)

References 6 publications

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“…Aside from the small crevice volume for the Flat combustion chamber, a possible explanation for this result is that the definitions of lean limit and EGR limit never give the turbulence generating designs a chance to prove that they can extend lean limit and EGR limit compared to the Flat. But in the future HC emissions can not be neglected and a lean limit defined at 5% COV imep [1], [2], [9] is likely to produce too much HC emissions. EGR combined with a three-way catalyst shows the lowest emission values at the price of a lower efficiency than lean burn.…”

Section: Discussionmentioning

confidence: 99%

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Combustion Chambers for Natural Gas SI Engines Part 2: Combustion and Emissions

Olsson¹,

Johansson²

1995

SAE Technical Paper Series

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The objective of this paper is to investigate how the combustion chamber design will influence combustion parameters and emissions in a natural gas SI engine.Ten different geometries were tried on a converted Volvo TD102 engine. For the different combustion chambers emissions and the pressure in the cylinder have been measured. The pressure in the cylinder was then used in a one-zone heat-release model to get different combustion parameters. The engine was operated unthrottled at 1200 rpm with different values of air/fuel ratio and EGR. The air/fuel ratio was varied from stoichiometric to lean limit. EGR values from 0 to 30% at stoichiometric air/fuel ratio were used.The results show a remarkably large difference in the rate of combustion between the chambers. The cycle-to-cycle variations are fairly independent of combustion chamber design as long as there is some squish area and the air and the natural gas are well mixed.Geometries that give the fastest combustion give the highest NO x values at λ=1.2, but at λ>1.5, which is normally designated lean-burn, the differences are smaller. The lowest NO x values for lean burn were obtained with the geometries that gives fast combustion.The HC emissions display some correlation between high combustion rate and low levels of HC emissions, but combustion chambers with dead zones and large total combustion chamber areas give higher HC contents than the combustion rate alone would indicate.Indicated efficiency is reduced for combustion chambers with a large total combustion chamber surface area and thus large heat losses. High levels of turbulence also tend to reduce the efficiency for the same reason.

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Section: Discussionmentioning

confidence: 99%

“…This ratio corresponds well to the ratio used in present natural gas heavy duty engines [1], [2], [3]. Three geometries were, however, designed with a higher ratio to study the effect of compression ratio.…”

Section: Combustion Chambersmentioning

confidence: 99%

Combustion Chambers for Natural Gas SI Engines Part 2: Combustion and Emissions

Olsson¹,

Johansson²

1995

SAE Technical Paper Series

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“…It is also worthy of note that the sequence of the segment is important, as a ratio of 8:2 is greater compared to a ratio of 2:8. Therefore, the flow and turbulence in the engine chamber requires uniformity to a certain degree and later a little variation or reduction in flow towards the end of the combustion process to stabilize flame ignition as described by [6].…”

Section: Segmented Modelmentioning

confidence: 99%

“…The Nebula combustion chamber used by [5] is such that the bowl shape forces the swirl to develop into colliding air flows thereby creating the desired great turbulence and fast burn effect. [6] went a step further by implementing the Squish, Nebula, and another named Tokyo Gas, TG with similar purpose as the Nebula but different in that the TG was described as having "a cylindrical dent with semi-circular slants oppositely shaped". The resulting effect of the TG is large turbulence at the cylinder wall and weak turbulence in the center of the cylinder to stabilize flame ignition.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Multi-Zone Models for Spark Ignition Engine Fueled With Ethanol

Dare

Olatunde

Ismail

et al. 2021

IIUMEJ

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This research is aimed at investigating the effect of using ethanol (E100) in multi-zone model analysis consisting of multi-combustion chamber zoning cases. The first case considered is a three-zone model that has an unburned zone, burned zone, and transitory zone. The second case model is also three-zone, consisting of an unburned zone and two partitioned burned zones. The burned zone was imagined partitioned into burned zone-1 and burned zone-2 under uneven fuel distribution having different equivalent ratios. The third case is a four-zone model including two regions of burned zone, an unburned zone and a transitory zone, which is unburned burned zone containing a mixture of unburned and burned gases. Arbitrary constants for each of the unburned (CC1) and burned (CC2) Zone leakages in the unburned burned Zone are 0.00025, 0.0005, 0.001, 0.002, 0.005, 0.1 and 0.5. The Mass Fraction Burned (MFB) for zone-1, x1 and burned zone-2, x2 are computed using Partitioned Burnt Zones Ratios (PBZR) of 2:8, 3:7, 4:6, 5:5, 6:4, 7:3 and 8:2. Two equivalent ratios, one for each fuel MFB (?1, ?2), (0.8, 0.6) and (0.6, 0.8) are analyzed using fuel blends of varying percentage. A comparison of values of the three zoning cases is done using peak values from the three-zone models to evaluate the four-zone model. The model was compared with a spark ignition engine (SIE) operating with a premium motor spirit (PMS) serving as baseline. The engine operating conditions were set at an engine speed of 2000 rpm, -35bTDC ignition time, and burn duration at 60 oC. The indicated mean effective pressure (IMEP), thermal efficiency (?), cylinder pressure and emission fraction from the developed models and those of two-zone analysis obtained agreed with literature values. The result showed it is undesirable to have a high volume of burned charge as infiltrate. The three-zone segmented model predicted the highest engine thermal efficiency and peak pressure at mass burn ratio of 7:3. A general reduction in N2 emission was observed for the three-zone transitional and four-zone models. ABSTRAK: Kajian ini menilai kesan etanol (E100) dalam analisis model zon-berbilang yang terdapat pada masalah pengezonan kebuk pembakaran-berbilang. Kes pertama yang diambil kira adalah model tiga-zon yang mempunyai zon tidak terbakar, zon terbakar dan zon peralihan. Model kedua merupakan juga tiga-zon yang terdiri daripada zon tidak-terbakar dan dua zon bahagian yang terbakar. Zon yang terbakar dibahagikan kepada zon-1 terbakar dan zon-2 terbakar di bawah kebakaran tidak sekata yang mempunyai nisbah berlainan. Kes ketiga adalah model zon-keempat termasuk dua kawasan zon terbakar, zon tidak-terbakar dan zon peralihan iaitu zon terbakar tidak-terbakar di mana ia adalah campuran gas terbakar dan tidak-terbakar. Tetapan sebarangan bagi setiap zon kebocoran tidak-terbakar (CC1) dan terbakar (CC2) dalam zon terbakar tidak-terbakar adalah 0.00025, 0.0005, 0.001, 0.002, 0.005, 0.1 dan 0.5. Pecahan Jisim Terbakar (MFB) bagi zon-1, x1 dan zon-2 terbakar, x2 dikira menggunakan Nisbah Zon Bahagian Terbakar (PBZR) sebanyak 2:8, 3:7, 4:6, 5:5, 6:4, 7:3 dan 8:2. Nisbah dua persamaan, setiap satu bahan api MFB adalah (?1, ?2), (0.8, 0.6) dan (0.6, 0.8) dan diuji menggunakan pelbagai peratus bahan api campuran. Nilai perbandingan bagi tiga kes zon dibuat menggunakan nilai puncak dari model tiga-zon bagi menilai model empat-zon. Model ini dibandingkan dengan enjin cucuhan bunga api (SIE) beroperasi dengan motor alkohol premium (PMS) sebagai garis asas. Keadaan operasi enjin adalah dihadkan pada 2000 rpm kelajuan enjin, masa pencucuhan -35bTDC dan tempoh pembakaran pada 60 oC. Tekanan berkesan min tertunjuk (IMEP), kecekapan haba tertunjuk (?), tekanan silinder dan pecahan pengeluaran dari model yang dibangunkan dan analisis dua-zon yang terhasil adalah sama dengan nilai literatur. Dapatan kajian menunjukkan cas terbakar pada isipadu yang banyak adalah tidak diingini sebagai penyerap. Model tiga bahagian zon menunjukkan kecekapan haba enjin tertinggi dan tekanan puncak pada jisim bakar dengan nisbah 7:3. Manakala, pengurangan umum telah diperhatikan pada pengeluaran N2 di peralihan tiga-zon dan model empat zon.

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“…This pushes the scientific society and authorized institutions to review the current legislations to reduce the emission [12,13]. The remarkable increase in the pollutants comes from the fast growth in vehicle production [14]. Other important sources are the fuel factor, the operating condition and performance, and the engine mechanical condition.…”

Section: Introductionmentioning

confidence: 99%

Emission components characteristics of a bi-fuel vehicle at idling condition

2011

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Natural gas (NG) represents today a promising alternative to conventional fuels for road vehicles propulsion, since it is characterized by a relatively low cost, better geopolitical distribution than oil, and lower environmental impact. This explains the current spreading of compressed natural gas (CNG) fuelled spark ignition (SI) engine, above all in the bi-fuel version, which is able to run either with gasoline or with NG. However, the aim of the present investigation is to evaluate the emission characteristics at idling condition. The vehicle engine was converted to bifueling system from a gasoline engine, and operated separately either with gasoline or CNG. Two different fuel injection systems (i.e., multi-point injection (MPI)sequential and closed-loop venturi-continuous) are used, and their influences on the formation of emissions at different operating conditions are examined. A detailed comparative analysis of the engine exhaust emissions using gasoline and CNG is made. The results indicate that the CNG shows low air index and lower emissions of carbon monoxide (CO), carbon dioxide (CO 2 ), and total hydrocarbon (THC) compared to gasoline.

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Basic Research on Combustion Chambers for Lean Burn Gas Engines

Cited by 16 publications

References 6 publications

Combustion Chambers for Natural Gas SI Engines Part 2: Combustion and Emissions

Combustion Chambers for Natural Gas SI Engines Part 2: Combustion and Emissions

Investigation of Multi-Zone Models for Spark Ignition Engine Fueled With Ethanol

Emission components characteristics of a bi-fuel vehicle at idling condition

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