Hydrocarbon Emissions from a HAJI Equipped Ultra-lean Burn SI Engine

Lawrence, Jeremy; Watson, Harry C.

doi:10.4271/980044

Cited by 37 publications

(14 citation statements)

References 5 publications

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“…While the diesel truck and gasoline passenger car models are validated versus engine dynamometer data, the LPG truck model is not validated because the DI-JI engine concept is still in a preliminary stage with funding for prototyping and experimental testing still unavailable. However, considering that the predicted fast rates of combustion of the DI-JI engine concept are in line with previous experiments with inhomogeneous charge [19] and homogeneous charge [15][16][17][18][19][20][21] configurations, they are therefore quite reliable; the brake efficiency predictions just follow these fast rates of combustion and share their reliability. The predicted top brake efficiencies, but even more so the predicted part-load efficiencies of the DI-JI LPG engine, are very significant, because they show the opportunity to achieve not only the diesel top brake Computed brake efficiency map of a 4-l, naturally aspirated, stoichiometric gasoline engine for a passenger car (BMEP versus engine speed for various brake efficiencies (per cent)) efficiencies but also the diesel part-load brake efficiencies on igniting with reacting jets controlled by a spark discharge to produce a slightly lean mixture within part of the in-cylinder volume.…”

Section: Previous Experimental and Latest Computational Resultssupporting

confidence: 84%

“…The JI pre-chamber is designed to be fitted within the traditional spark plug thread of diameter 14 mm to increase only marginally the level of complexity of designing a cylinder head with a JI pre-chamber replacing the standard main-chamber spark plug and to allow testing on the existing hardware. The 1-1.5 cm 3 volume and the operation with a slightly fuel-rich mixture are the values that have provided the best results so far [15][16][17][18][19][20][21]. A standard LP GDI injector (e.g.…”

Section: Some Notes On Pre-chamber Design and Injector Selectionmentioning

confidence: 99%

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Experimental and computational analysis of the combustion evolution in direct-injection spark-controlled jet ignition engines fuelled with gaseous fuels

Boretti

Paudel

Tempia

2010

Proceedings of the Institution of Mechanical Engineers, Part D:

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Jet ignition and direct fuel injection are potential enablers of higher-efficiency, cleaner internal combustion engines (ICEs), where very lean mixtures of gaseous fuels could be burned with pollutants formation below Euro 6 levels, efficiencies approaching 50 per cent full load, and small efficiency penalties operating part load. The lean-burn direct-injection (DI) jet ignition ICE uses a fuel injection and mixture ignition system consisting of one main-chamber DI fuel injector and one small jet ignition pre-chamber per engine cylinder. The jet ignition pre-chamber is connected to the main chamber through calibrated orifices and accommodates a second DI fuel injector. In the spark plug version, the jet ignition pre-chamber includes a spark plug which ignites the slightly rich pre-chamber mixture which then, in turn, bulk ignites the ultra-lean stratified main-chamber mixture through the multiple jets of hot reacting gases entering the in-cylinder volume. The paper uses coupled computer-aided engineering and computational fluid dynamics (CFD) simulations to provide better details of the operation of the jet ignition pre-chamber (analysed so far with downstream experiments or stand-alone CFD simulations), thus resulting in a better understanding of the complex interactions between chemistry and turbulence that govern the pre-chamber flow and combustion.

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Section: Previous Experimental and Latest Computational Resultssupporting

confidence: 84%

Section: Some Notes On Pre-chamber Design and Injector Selectionmentioning

confidence: 99%

Experimental and computational analysis of the combustion evolution in direct-injection spark-controlled jet ignition engines fuelled with gaseous fuels

Boretti

Paudel

Tempia

2010

Proceedings of the Institution of Mechanical Engineers, Part D:

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“…The jets of reacting gases enhance combustion of lean stratified mixtures within the main chamber through a combination of large thermal energy, multiple ignition points and presence of active radical species. Prior simulations and experiments jet igniting homogeneous charges of hydrocarbon fuels have shown the opportunity to achieve very fast combustion rates with reduced formation of HC and CO even running very lean [24][25][26][27][28][29][30]. Lean stratified mixtures are expected to further enhance the always lean burn option enabled by jet ignition.…”

Section: Benefits Of Direct Injection and Jet Ignitionmentioning

confidence: 99%

“…This is a major limitation of traditional pre-chamber engines even at very lean operating conditions. The jet ignition device was originally intended to replace a standard 14 mm thread spark plug in port fuel injected engines with lean premixed combustion [24][25][26][27][28][29][30]. Minimum development investments could allow production of miniaturized jet ignition devices the same size as a traditional spark plug with better opportunity for the technology to be applied to existing engine layouts.…”

Section: Benefits Of Direct Injection and Jet Ignitionmentioning

confidence: 99%

Direct Injection and Spark Controlled Jet Ignition to Convert A Diesel Truck Engine to LPG

Boretti

2010

SAE Technical Paper Series

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Jet ignition and direct fuel injection are potential enablers of higher efficiency, cleaner Internal Combustion Engines (ICE). Very lean mixtures of gaseous fuels could be burned with pollutants formation below Euro 6 levels (in the ultra-lean mode), efficiencies approaching 50% full load and small efficiency penalties when operating part load. The lean burn Direct Injection Jet Ignition (DI-JI) ICE uses a fuel injection and mixture ignition system comprising one main chamber direct fuel injector and one small size jet ignition pre-chamber per engine cylinder. The jet ignition pre-chamber is connected to the main chamber through calibrated orifices and accommodates a second direct fuel injector. In the spark plug version, the jet ignition pre-chamber includes a spark plug that ignites the slightly rich pre-chamber mixture that then bulk ignites the ultra lean, stratified main chamber mixture through multiple jets of hot reacting gases entering the in-cylinder. This paper uses coupled CAE and CFD simulations to provide better details of the operation of the jet ignition pre-chamber. They have been analysed so far with downstream experiments or standalone CFD simulations, enabling a better understanding of the complex interactions between chemistry and turbulence that governs the pre-chamber flow and combustion. CAE simulations are performed for a production 11 litre, in-line six, 24 valve Diesel Truck engine. It is turbo charged, with inter cooler and cooled Exhaust Gas Recirculation (EGR). It is modified to fit the jet ignition pre-chamber and run propane fuel by replacing the Diesel fuel injector with a direct injector for the LPG fuel plus reducing the compression ratio and changing the piston shape. Operation full load with same air-to-fuel equivalence ratio λ=1.55 is considered first. The load of the DI-JI LPG engine is then reduced by reducing the quantity of fuel injected Diesel like. The DI-JI LPG engine shows better than Diesel full and part load performances.

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“…The jet ignition concept was developed by Prof. H.C. Watson and his co-workers in the late 1980s. Jet ignition was historically proposed to run the engine throttle-less and diesel-like by using homogeneous fuel air mixtures from stoichiometric to ultra-lean, [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Design of Direct Injection Jet Ignition High Performance Naturally Aspirated Motorcycle Engines

Boretti¹

2019

Designs

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Thanks to the adoption of high pressure, direct injection and jet ignition, plus electrically assisted turbo-compounding, the fuel conversion efficiency of Fédération Internationale de l'Automobile (FIA) F1 engines has been spectacularly improved up to values above 46% peak power, and 50% peak efficiency, by running lean of stoichiometry stratified in a high boost, high compression ratio environment. Opposite, Federation Internationale de Motocyclisme (FIM) Moto-GP engines are still naturally aspirated, port injected, spark ignited, working with homogeneous mixtures. This old fashioned but highly optimized design is responsible for relatively low fuel conversion efficiencies, and yet delivers an outstanding specific power density of 200 kW/liter. The potential to improve the fuel conversion efficiency of Moto-GP engines through the adoption of direct injection and jet ignition, prevented by the current rules, is herein discussed based on simulations. As two-stroke engines may benefit from direct injection and jet ignition more than four-stroke engines, the opportunity of a return of two-stroke engines is also argued, similarly based on simulations. About the same power, but at a better fuel efficiency, of today’s 1000 cm3 four stroke engines, may be obtained with lean stratified direct injection jet ignition engines, four-stroke of 1450 cm3, or two-stroke of 1050 cm3. About the same power and fuel efficiency may also be delivered with stoichiometric engines direct injection jet ignition two-stroke of 750 cm3.

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Hydrocarbon Emissions from a HAJI Equipped Ultra-lean Burn SI Engine

Cited by 37 publications

References 5 publications

Experimental and computational analysis of the combustion evolution in direct-injection spark-controlled jet ignition engines fuelled with gaseous fuels

Experimental and computational analysis of the combustion evolution in direct-injection spark-controlled jet ignition engines fuelled with gaseous fuels

Direct Injection and Spark Controlled Jet Ignition to Convert A Diesel Truck Engine to LPG

Design of Direct Injection Jet Ignition High Performance Naturally Aspirated Motorcycle Engines

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