Regulated and unregulated emissions from a spark-ignition engine fuelled with low-blend ethanol–gasoline mixtures

Author(s):  
F-J Liu ◽  
P Liu ◽  
Z Zhu ◽  
Y-J Wei ◽  
S-H Liu

The effects of ethanol addition to gasoline on the exhaust emissions (including regulated and unregulated emissions) and the conversion efficiencies of the three-way catalyst (TWC) were investigated in a three-cylinder spark-ignition (SI) gasoline engine. Three typical fuel blends – commercial 93# (Research Octane Number) gasoline (E0), E10, and E20 (with 0 per cent, 10 per cent, and 20 per cent ethanol in the blends by volume) – were used in the experiment. Unregulated emissions were measured by gas chromatography with a pulsed discharge helium ionization detector. Experimental results show that the regulated emissions of hydrocarbon, carbon monoxide, and nitrogen oxides decreased before and after the TWC with the increase of ethanol fraction in the fuel blends. However, the unregulated emissions of ethanol, acetaldehyde, and formaldehyde increased with the increase of ethanol fraction and decreased with increased engine speed and/or torque. Ethanol emission was not detected when fuelled with gasoline (E0). Ethanol emission was intensively influenced by the exhaust temperature and disappeared when the exhaust temperature was higher than 900 K for E10 and E20 operation. Acetaldehyde emission definitely comes from the oxidation of ethanol; the engine speed and load have opposite effects on acetaldehyde emission. Both ethanol and acetaldehyde can be converted effectively by the TWC. More formaldehyde was emitted at higher engine speed and lower load operating conditions.

2021 ◽  
Vol 22 (2) ◽  
pp. 339-351
Author(s):  
A. A. Dare ◽  
Olanrewaju Olatunde ◽  
O. S. Ismail ◽  
A. S. Shote ◽  
O. J. Alamu ◽  
...  

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.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4141
Author(s):  
Christine Mounaïm-Rousselle ◽  
Pierre Bréquigny ◽  
Clément Dumand ◽  
Sébastien Houillé

The objective of this paper is to provide new data about the possibility of using ammonia as a carbon-free fuel in a spark-ignition engine. A current GDI PSA engine (Compression Ratio 10.5:1) was chosen in order to update the results available in the literature mainly obtained in the CFR engine. Particular attention was paid to determine the lowest possible load limit when the engine is supplied with pure ammonia or a small amount of H2, depending on engine speed, in order to highlight the limitation during cold start conditions. It can be concluded that this engine can run stably in most of these operating conditions with less than 10% H2 (of the total fuel volume) added to NH3. Measurements of exhaust pollutants, and in particular NOx, have made it possible to evaluate the possibility of diluting the intake gases and its limitation during combustion with pure H2 under slightly supercharged conditions. In conclusion, the 10% dilution limit allows a reduction of up to 40% in NOx while guaranteeing stable operation.


Author(s):  
Pin Zeng ◽  
Robert G. Prucka ◽  
Zoran S. Filipi ◽  
Dennis N. Assanis

This paper proposes a technique for reconstructing the cylinder pressure traces of a spark-ignition engine based on three inputs: spark-timing, speed and load. This method is an extension of previous work for reconstructing cylinder pressure in a heavy-duty diesel engine [1]. The previous study utilized only two inputs for cylinder pressure reconstruction, e.g. engine speed and load, hence implying optimal combustion phasing. The new method adds one more input to allow reconstruction of pressure traces from cycles with combustion phasing altered based on emissions or knock constraints. The method was applied to a 4-cylinder, 2.4-liter DaimlerChrysler gasoline engine. Comparisons between measured and reconstructed cylinder pressure traces demonstrate that the method is applicable over the majority of the gasoline engine operating range. Reconstructed cylinder pressure traces have also been used to carry out engine heat transfer and heat release analyses. Problems associated with the application of this method to gasoline engine are also discussed.


Author(s):  
Nicolo` Cavina

The diagnosis of misfire events (or missing combustions) is enforced by On-Board Diagnostics regulations (such as CARB OBD II or European OBD) over the whole engine operating range, for all vehicles equipped with spark ignition engines. Such regulations define both the minimum misfire frequency that is to be detected (related to catalyst damage and/or increased hydrocarbons emissions), and the various misfire patterns that the diagnostic algorithm should be able to detect. In particular, single (no more than one missing combustion per engine cycle) and multiple (more than one misfiring cylinder within the same engine cycle) misfire patterns are to be diagnosed, and the cylinder in which the misfire took place is to be isolated only when single misfires take place (cylinder identification is still not mandatory for multiple misfires). Various single misfire detection methodologies have been successfully developed in recent years (mostly based on the engine speed signal), and this type of misfire diagnosis is still challenging for engines with a high number of cylinders, especially during operating conditions characterized by high engine speed and low load. On the other hand, the detection of multiple misfires is still difficult even for the typical four cylinder engine, since their effects on the engine speed trend have not yet been clarified. In fact, a misfire occurrence is characterized by a sudden engine speed decrease and a subsequent damped torsional vibration. In case of multiple misfires, the engine speed oscillation induced by the first misfiring cylinder may still be present when the second missing combustion takes place, and the resulting engine speed waveform may be erroneously interpreted by the diagnostic algorithm, thus resulting in the improper cylinder being identified or missed detection of a misfiring cylinder. This paper deals with the identification of a specific pattern in the instantaneous engine speed trend, induced by a missing combustion and characteristic of the system under study, that allows performing the desired multiple misfire detection. The methodology has been designed in order to be run on-board, thus requiring low computational power and memory allocation. Its implementation has shown that false alarms can be avoided and correct cylinder isolation is possible, also in presence of multiple misfires. Experimental tests have been performed on a 1.2 liter spark ignition engine mounted in a test cell. Various multiple misfire patterns have been induced by controlling ignition and injection of the various cylinders. In-cylinder pressure signals have been acquired together with the instantaneous engine speed, in order to verify the capability of the methodology.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4034
Author(s):  
Paolo Iodice ◽  
Massimo Cardone

Among the alternative fuels existing for spark-ignition engines, ethanol is considered worldwide as an important renewable fuel when mixed with pure gasoline because of its favorable physicochemical properties. An in-depth and updated investigation on the issue of CO and HC engine out emissions related to use of ethanol/gasoline fuels in spark-ignition engines is therefore necessary. Starting from our experimental studies on engine out emissions of a last generation spark-ignition engine fueled with ethanol/gasoline fuels, the aim of this new investigation is to offer a complete literature review on the present state of ethanol combustion in last generation spark-ignition engines under real working conditions to clarify the possible change in CO and HC emissions. In the first section of this paper, a comparison between physicochemical properties of ethanol and gasoline is examined to assess the practicability of using ethanol as an alternative fuel for spark-ignition engines and to investigate the effect on engine out emissions and combustion efficiency. In the next section, this article focuses on the impact of ethanol/gasoline fuels on CO and HC formation. Many studies related to combustion characteristics and exhaust emissions in spark-ignition engines fueled with ethanol/gasoline fuels are thus discussed in detail. Most of these experimental investigations conclude that the addition of ethanol with gasoline fuel mixtures can really decrease the CO and HC exhaust emissions of last generation spark-ignition engines in several operating conditions.


2017 ◽  
Vol 18 (9) ◽  
pp. 951-970 ◽  
Author(s):  
Riccardo Amirante ◽  
Elia Distaso ◽  
Paolo Tamburrano ◽  
Rolf D Reitz

The laminar flame speed plays an important role in spark-ignition engines, as well as in many other combustion applications, such as in designing burners and predicting explosions. For this reason, it has been object of extensive research. Analytical correlations that allow it to be calculated have been developed and are used in engine simulations. They are usually preferred to detailed chemical kinetic models for saving computational time. Therefore, an accurate as possible formulation for such expressions is needed for successful simulations. However, many previous empirical correlations have been based on a limited set of experimental measurements, which have been often carried out over a limited range of operating conditions. Thus, it can result in low accuracy and usability. In this study, measurements of laminar flame speeds obtained by several workers are collected, compared and critically analyzed with the aim to develop more accurate empirical correlations for laminar flame speeds as a function of equivalence ratio and unburned mixture temperature and pressure over a wide range of operating conditions, namely [Formula: see text], [Formula: see text] and [Formula: see text]. The purpose is to provide simple and workable expressions for modeling the laminar flame speed of practical fuels used in spark-ignition engines. Pure compounds, such as methane and propane and binary mixtures of methane/ethane and methane/propane, as well as more complex fuels including natural gas and gasoline, are considered. A comparison with available empirical correlations in the literature is also provided.


2021 ◽  
pp. 146808742110399
Author(s):  
Veniero Giglio ◽  
Livia Della Ragione ◽  
Alessandro di Gaeta ◽  
Natale Rispoli

Ionization current measured at the spark plug during combustion in spark ignition engines has often been proposed to determine the crank-angle at combustion pressure peak, namely the peak pressure angle, for the purpose of regulating spark timing to attain maximum brake torque (MBT). The proposal is based on the assumption that agreement exists between peak pressure angle and the angular position of the ionization current second peak, although no one has ever proved it by an appropriate statistical analysis. The aim of this work, for the first time and by rigorous statistical methods, is to prove the agreement between Peak Pressure Angle and Ionization Current Second Peak Angle (ICSPA), without which a MBT control via ICSPA would be ineffective. Our experimental database consisted of about 9000 pairs of Peak Pressure Angle and Ionization Current Second Peak Angle values corresponding to 90 different operating conditions of a spark ignition engine. A two-sample comparison was first carried out between mean values of Peak Pressure Angle and Ionization Current Second Peak Angle, which showed a statistically significant difference between them. Then Bland-Altman analysis (Lancet, 1986), widely known and used for checking agreement between two different measurement methods, was conducted. It demonstrated that under almost all the experimental operating conditions, there was no agreement between the Ionization Current Second Peak Angle and the Peak Pressure Angle.


2018 ◽  
Vol 43 (46) ◽  
pp. 21592-21602 ◽  
Author(s):  
Juan P. Gómez Montoya ◽  
Andrés A. Amell ◽  
Daniel B. Olsen ◽  
German J. Amador Diaz

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