Lean Burn Combustion of Iso-Octane in a Rapid Compression Machine Using Dual Mode Turbulent Jet Ignition System

Vedula, Ravi Teja; Gentz, Gerald; Stuecken, Tom; Toulson, Elisa; Schock, Harold

doi:10.4271/03-11-01-0007

Cited by 15 publications

(9 citation statements)

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“…Other benefits associated to this active system are the stratification of the charge and the sharp reduction of the emitted HC and NO x [28]. In passive systems [29], there is no additional fuel addition in the pre-chamber, so its air-to-fuel ratio is not directly controlled. In port fuel injection (PFI), engines λ is essentially equal in both chambers, while in direct injection (GDI) engines λ differences between chambers can be indirectly generated by adjusting the pre-chamber and injector relative spatial position up to a some extent [30].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the passive pre-chamber ignition concept for future high compression ratio turbocharged spark-ignition engines

et al. 2019

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The pre-chamber ignition concept is an attractive strategy to enable the operation of spark-ignition engines in lean or diluted conditions keeping a suitable combustion process. According to the results the benefits in lean conditions include the fastening of the combustion process, the improvement of combustion stability, the increase of combustion efficiency by lowering carbon monoxide and hydrocarbons emissions. Thus, the pre-chamber ignition concept, especially in its passive version, arises as a promising alternative for future spark-ignition engines for passenger car applications. In this framework, an experimental investigation has been carried out to evaluate the potential of passive pre-chamber ignition concept in a high compression ratio, turbocharged, port fueled spark-ignition engine, using 95 Research Octane Number gasoline. As a first step, a 1D Wave Action Model was generated to design the pre-chamber geometry taking the fuel available at the start of pre-chamber combustion and the pressure difference between the main chamber and pre-chamber as key parameters. In a second step, these pre-chamber designs were experimentally validated at high load/speed conditions (4500 rpm, 12.5 bar Indicated Mean Effective Pressure) and compared with the conventional spark-ignition concept. Experimental results show how the passive pre-chamber concept increases efficiency with good combustion stability and high combustion efficiency in stoichiometric conditions. Nevertheless, maximum lambda attainable with the passive system is similar than that of the conventional spark and much lower compared to the maximum levels reported for the active system.

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Section: Introductionmentioning

confidence: 99%

Evaluation of the passive pre-chamber ignition concept for future high compression ratio turbocharged spark-ignition engines

et al. 2019

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“…11 Some drawbacks of air dilution are higher combustion duration and deterioration, which can lead in higher engine cyclic variability. 12…”

Section: Introductionmentioning

confidence: 99%

Exploring the part load lean limit of a direct injection spark ignition engine fueled with ethanol

Golke

Prante

Garlet

et al. 2022

International Journal of Engine Research

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Stringent environmental legislation demands development of internal combustion engines seeking higher thermal efficiency to reduce greenhouse gas emissions. Brazilian governmental programs like ROTA 2030 and RenovaBio drive the research and development of highly efficient engines fueled with biofuels, like sugarcane bioethanol, that has a near to zero carbon footprint. Some technologies such as gasoline direct injection, variable valve train, and turbocharging were implemented in downsized Spark Ignition (SI) engines in order to reach higher thermal efficiencies and decrease CO2 emissions. Homogeneous lean combustion in SI operation can improve fuel consumption and reduce exhaust gas emissions. However, it is limited by combustion instability and the three-way-catalyst (TWC) inability to work properly converting nitrogen oxides (NOx). With lean combustion the NOx emissions could be significantly reduced, enabling the use of lean NOx trap (LNT) as an effective lower cost after treatment system. To explore the limits of homogeneous lean combustion in SI engines, experimental tests were performed to investigate performance, efficiency, combustion, and emission parameters of a multi-cylinder Ford 1.0l Ti-VCT EcoBoost engine fueled with hydrous ethanol. Hydrous ethanol is a commercial Brazilian fuel which has greater laminar flame speed and higher dilution tolerance than gasoline, and thus can increase combustion stability. Different fuel direct injection strategies were explored at part load (below 8.0 bar IMEP) at engine speed of 1500 rpm. Air-to-fuel ratio was varied from stoichiometric (lambda 1.0) to lambda 1.5. The limit of stable homogeneous lean combustion (COVIMEP ≤ 3.0%) was achieved in lambda 1.4. The lowest indicated load of 2.1 bar IMEP was limited by combustion stability at lambda 1.3. The maximum indicated efficiency was 36.9% at indicated load of 8.0 bar IMEP and lambda 1.4. The NOx emissions dropped below 1.4 g/kWh at 4.0 bar IMEP and lambda 1.4.

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“…2) while reducing NOx formations substantially. [17][18][19] Provided an effective design and fabrication of the hardware, the active PCC concept is the favored option for a wider range of applications.…”

Section: Introductionmentioning

confidence: 99%

“…Alternatively, an active pre-chamber is equipped with a separate fuel supply system to enrich the mixture in the pre-chamber, allowing a better control to extend the lean limit of the engine effectively (global-λ > 2) while reducing NOx formations substantially. 17–19 Provided an effective design and fabrication of the hardware, the active PCC concept is the favored option for a wider range of applications.…”

Section: Introductionmentioning

confidence: 99%

Estimates of the air-fuel ratio at the time of ignition in a pre-chamber using a narrow throat geometry

Hlaing

Silva

Marquez

et al. 2021

International Journal of Engine Research

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The benefits of pre-chamber combustion (PCC), such as improved engine efficiency and reduced NOx emissions, are primarily observed when operating at lean conditions with an active pre-chamber, where auxiliary fuel is supplied directly to the pre-chamber. Estimating the pre-chamber excess air ratio (λ) is important in the active pre-chamber concept to gain insights into the pre-chamber combustion phenomenon. Experimental investigations were performed using a narrow-throat pre-chamber at global-λ 1.6, 1.8, and 2.0. The fraction of fuel energy injected in the pre-chamber over the total fuel energy was fixed at 3%, 7%, and 13% for each global-λ. The mixture formation process inside the pre-chamber is first simulated using the 1-D simulation software GT-Power to analyze the pre-chamber λ at the ignition timing. However, the 1-D results were unable to reproduce the experimental observations on the pre-chamber pressure buildup accurately. Upon simulating the same conditions using the 3-D CFD software CONVERGE, the pre-chamber λ estimated from the CFD model is well-correlated to the experimental data. The CFD results indicate that the amount of fuel trapped in the pre-chamber at the inlet valve closing timing is over-predicted by the 1-D simulations. A correlation between the injected and the trapped fuel in the pre-chamber is proposed by theoretical scavenging models and applied to the 1-D simulation results to improve pre-chamber λ prediction accuracy.

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Lean Burn Combustion of Iso-Octane in a Rapid Compression Machine Using Dual Mode Turbulent Jet Ignition System

Cited by 15 publications

References 0 publications

Evaluation of the passive pre-chamber ignition concept for future high compression ratio turbocharged spark-ignition engines

Evaluation of the passive pre-chamber ignition concept for future high compression ratio turbocharged spark-ignition engines

Exploring the part load lean limit of a direct injection spark ignition engine fueled with ethanol

Estimates of the air-fuel ratio at the time of ignition in a pre-chamber using a narrow throat geometry

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