A Normally Aspirated Spark Initiated Combustion System Capable of High Load, High Efficiency and Near Zero NOx Emissions in a Modern Vehicle Powertrain

Attard, William P.; Parsons, Patrick

doi:10.4271/2010-01-2196

Cited by 79 publications

(36 citation statements)

References 49 publications

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“…Attard and colleagues reported a peak 42% net thermal efficiency for a TJI system mounted on a GM (General Motors) Ecotec 4-valve pent roof combustion system. 5 The 42% efficiency corresponded to ∼6 bar net mean effective pressure (NMEP) at a speed of 1500 r/min with ∼1.6 normalized air/fuel ratio (lambda). The reported thermal efficiency was associated with an 18% improvement in fuel consumption of a lean-operated TJI system compared to conventional stoichiometric spark ignition (SI) engines at the same load and speed.…”

Section: Introductionmentioning

confidence: 99%

“…1–3 The supplementary air supply and its method of delivery to the pre-chamber of a DM-TJI system are the main modification to the technology’s predecessor, turbulent jet ignition (TJI) system. 4–9…”

Section: Introductionmentioning

confidence: 99%

“…The reported thermal efficiency was associated with an 18% improvement in fuel consumption of a lean-operated TJI system compared to conventional stoichiometric spark ignition (SI) engines at the same load and speed. 5 The TJI systems, with their high level of improvement in thermal efficiency compared to conventional internal combustion (IC) engines, face complications with engine-out emissions. One of the early challenges of the three-way catalytic converter (TWC), and indeed one that persists today, is the conversion efficiency of a TWC for nitrogen oxides (NOx).…”

Section: Introductionmentioning

confidence: 99%

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Experiments and modeling of a dual-mode, turbulent jet ignition engine

Tolou

Schock

2019

International Journal of Engine Research

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The dual-mode, turbulent jet ignition system is a promising combustion technology to achieve high diesel-like thermal efficiency at medium to high loads and potentially exceed diesel efficiency at low-load operating conditions. The dual-mode, turbulent jet ignition systems to date proved a high level of improvement in thermal efficiency compared to conventional internal combustion engines. However, some questions were still unanswered. The most frequent question regarded power requirements for delivering air to the pre-chamber of a dual-mode, turbulent jet ignition system. In addition, there was no study available to predict the expected efficiency of a dual-mode, turbulent jet ignition engine in a multi-cylinder configuration. This study, for the first time, predicts the ancillary work requirement to operate the dual-mode, turbulent jet ignition system. It also presents a novel, reduced order, and physics-based model of the dual-mode, turbulent jet ignition engine with a pre-chamber valve assembly. The developed model was calibrated based on experimental data from the Prototype II dual-mode, turbulent jet ignition engine. The simulation results were in good agreement with the experimental data. The validity of the model was observed based on the standard metric of the coefficient of determination as well as comparison plots for in-cylinder pressures. Numerical predictions were compared to experiments for three metrics of main chamber combustion: gross indicated mean effective pressure, main chamber peak pressure, and main chamber phasing for the peak pressure. Predictions were within 5% of experimental data, with one exception of 6%. In addition, the absolute root mean square errors of in-cylinder pressures for both pre- and main-combustion chambers were below 0.35. The calibrated model was further studied to introduce a predictive and generalized model for dual-mode, turbulent jet ignition engines. Such a model can project engine behavior in a multi-cylinder configuration over the entire engine fuel map.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experiments and modeling of a dual-mode, turbulent jet ignition engine

Tolou

Schock

2019

International Journal of Engine Research

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“…16,17 Later, some variants of the pre-chamber combustion system were developed and studied 18–26 but did not cause enough concerns. Until a serial of studies on the application of PJI systems in gasoline engines were conducted by Attard et al 27–33 and proved a considerable improvement of power and economic performances in 2010–2012, this technology began to attract more and more attentions. Shah et al 34–36 carried out several experimental investigations on the performance and emission characteristics of pre-chamber systems in NG engines.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of pre-chamber jet ignition in a rapid compression machine and single-cylinder natural gas engine

Zhao

Wang

et al. 2019

International Journal of Engine Research

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Pre-chamber jet ignition is a promising combustion technology to achieve fast combustion in natural gas engines. First, the ignition and combustion characteristics of mixtures in a pre-chamber system with different diameter orifices were studied under engine-relevant pressures and temperatures in a rapid compression machine. The tested fuels, CH4/air stoichiometric mixtures, were diluted by different proportions of CO2/N2 to simulate the corresponding exhaust gas recirculation conditions in engines. High-speed photography was applied to visualize the jet ignition and combustion processes. The experimental results revealed that two ignition patterns existed in the pre-chambers depending on the diameter of orifices. Pre-chamber jet flame ignition pattern appeared when the orifice diameter of the pre-chamber exceeded a critical value, which produced jet flame and ignited the mixtures in the main chamber directly. Pre-chamber jet auto-ignition pattern produced jet which promoted the auto-ignition of mixture in the main chamber when the orifice diameter was smaller and presented much shorter combustion durations. Based on the experimental results in the rapid compression machine, a practical pre-chamber system was designed in a single-cylinder natural gas engine to investigate the combustion performance and emission characteristics. The experimental results indicated appropriate 0.8%–1.4% increases of indicated thermal efficiency were achieved by pre-chamber jet ignition due to the higher combustion efficiency and shorter combustion duration compared to conventional spark ignition. Lower total hydrocarbon and CO emissions but higher NO x emissions were produced by pre-chamber jet ignition due to the faster burning velocity and higher combustion temperature.

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“…MAHLE Powertrain has published numerous studies regarding their development of a TJI system for lean-burn SI engine operation. Attard and Parsons 24 tested the fueled prechamber MAHLE TJI system in an engine from a passenger vehicle. In these tests, propane was used as the auxiliary prechamber fuel, and the TJI demonstrated the ability to maintain stable operation up to λ = 2.0.…”

Section: Introductionmentioning

confidence: 99%

A computational study on the effect of the orifice size on the performance of a turbulent jet ignition system

Thelen

Toulson

2016

Proceedings of the Institution of Mechanical Engineers, Part D:

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Fully three-dimensional computational fluid dynamic simulations with detailed combustion chemistry of a turbulent jet ignition system installed in a rapid compression machine are presented. The turbulent jet ignition system is a prechamber-initiated combustion system intended to allow lean-burn combustion in spark ignition internal-combustion engines. In the presented configuration, the turbulent jet ignition prechamber has a volume that is 2% of the volume of the main combustion chamber in the rapid compression machine and is separated from the main chamber by a nozzle containing a single orifice. Four simulations with orifice diameters of 1.0 mm, 1.5 mm, 2.0 mm, and 3.0 mm respectively are presented in order to demonstrate the effect of the orifice diameter on the combustion behavior of the turbulent jet ignition process. Data generated by the simulations is shown including combustion chamber pressures, temperature fields, jet velocities and mass fraction burn durations. From the combustion pressure trace, the jet velocity, and other field data, five distinct phases of the turbulent jet ignition process are identified. These phases are called the compression phase, the prechamber combustion initiation phase, the cold jet phase, the hot jet phase, and the flow reversal phase. The four simulations show that the orifice diameter of 1.5 mm provides the fastest ignition and the fastest overall combustion as reflected in the 0–10% and 10–90% mass fraction burn duration data generated. Meanwhile, the simulation for the orifice diameter of 1.0 mm produces the highest jet velocity and has the shortest delay between the spark and the exit of a jet of hot gases into the main chamber but produces a slower burn duration than the simulation for the larger orifice diameter of 1.5 mm. The simulations for orifice diameters of 2.0 mm and 3.0 mm demonstrate that the combustion speed is reduced as the orifice diameter increases above 1.5 mm. Finally, a discussion is given which examines the implications that the results generated have in regard to implementation of the turbulent jet ignition system in an internal-combustion engine.

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A Normally Aspirated Spark Initiated Combustion System Capable of High Load, High Efficiency and Near Zero NOx Emissions in a Modern Vehicle Powertrain

Cited by 79 publications

References 49 publications

Experiments and modeling of a dual-mode, turbulent jet ignition engine

Experiments and modeling of a dual-mode, turbulent jet ignition engine

Experimental study of pre-chamber jet ignition in a rapid compression machine and single-cylinder natural gas engine

A computational study on the effect of the orifice size on the performance of a turbulent jet ignition system

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