High Injection Pressures at the Upper Load Limit of Stratified Operation in a DISI Engine

Buri, Stefan; Busch, Steve; Kubach, Heiko; Spicher, Ulrich

doi:10.4271/2009-01-2657

Cited by 23 publications

(10 citation statements)

References 3 publications

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“…(1) contains the sum of two terms, one according to the recommendations of ASTM G133 standard, which only considers the central zone of the wear tracks, and another one that estimates the W V in the two edges of the track [12]. The wear rate (W R ) was estimated as follows: (2) where F N is the normal load and l is the total sliding distance. All the tribological data shown in this work represent the average of, at least, three valid tests.…”

Section: Methodsmentioning

confidence: 99%

“…The automotive industry needs to accomplish the new energy and eco-friendly targets trying to reduce both the fuel consumption and the harmful emissions to the atmosphere, the latter objective requested by the European emission standards Euro 6 [1]. Gasoline direct injection (GDI) engines can fulfil those goals but pressure levels up to 80 MPa are required [2], which jointly with the poor lubricity of gasoline compel to replace the metallic sliding components by more wear resistant materials such as advanced ceramics. As a matter of fact, Pfister et al [3] found a good performance with high mechanical efficiency using a self-mated textured SiC cam/pusher system within a high-pressure 3-piston prototype pump for gasoline.…”

Section: Introductionmentioning

confidence: 99%

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Friction and wear behaviour of silicon carbide/graphene composites under isooctane lubrication

Llorente

Belmonte

2018

Journal of the European Ceramic Society

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The tribological performance of silicon carbide (SiC)/graphene nanoplatelets (GNPs) composites is analysed under oscillating sliding tests lubricated with isooctane, looking to explore their potential as components for gasoline direct injection (GDI) engines. High graphene filler contents (20 vol.% of GNPs) are required to substantially reduce the friction coefficient of SiC ceramics, attaining decreases on friction up to 30% independently of the applied load. For all materials and testing conditions a mild wear regime is evidenced. SiC/20 vol.% GNPs composite also enhances the wear resistance up to 35% at low load, but the addition of GNPs produces a deleterious effect as the load augments. The tribological behaviour depends on the formation and destabilization of a solid lubricant carbon-based tribofilm and strongly correlates with the mechanical properties of the tested materials.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Friction and wear behaviour of silicon carbide/graphene composites under isooctane lubrication

Llorente

Belmonte

2018

Journal of the European Ceramic Society

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“…Ongoing research and development on SGSC engines include higher injection pressures 109–111 and boosted operation (turbo- and/or super-charged) to extend the upper load limit of stratified operation without excessive engine-out soot production. 96,111–114 Multi-pulse injection (up to eight pulses per cycle) is being pursued aggressively both for mixture preparation (combustion stability; NOx, soot, and hydrocarbon emissions) and to avoid fuel impingement on surfaces (spark plug, 115 piston bowl, or cylinder wall).…”

Section: Sgsc Development Directionsmentioning

confidence: 99%

Invited Review: Combustion instability in spray-guided stratified-charge engines: A review

Fansler

Reuss

Sick

et al. 2015

International Journal of Engine Research

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This article reviews systematic research on combustion instabilities (principally rare, random misfires and partial burns) in spray-guided stratified-charge (SGSC) engines operated at part load with highly stratified fuel -air -residual mixtures. Results from high-speed optical imaging diagnostics and numerical simulation provide a conceptual framework and quantify the sensitivity of ignition and flame propagation to strong, cyclically varying temporal and spatial gradients in the flow field and in the fuel -air -residual distribution. For SGSC engines using multi-hole injectors, spark stretching and locally rich ignition are beneficial. Combustion instability is dominated by convective flow fluctuations that impede motion of the spark or flame kernel toward the bulk of the fuel, coupled with low flame speeds due to locally lean mixtures surrounding the kernel. In SGSC engines using outwardly opening piezo-electric injectors, ignition and early flame growth are strongly influenced by the spray's characteristic recirculation vortex. For both injection systems, the spray and the intake/compression-generated flow field influence each other. Factors underlying the benefits of multi-pulse injection are identified. Unresolved questions include (1) the extent to which piezo-SGSC misfires are caused by failure to form a flame kernel rather than by flame-kernel extinction (as in multi-hole SGSC engines); (2) the relative contributions of partially premixed flame propagation and mixing-controlled combustion under the exceptionally late-injection conditions that permit SGSC operation on E85-like fuels with very low NOx and soot emissions; and (3) the effects of flow-field variability on later combustion, where fuel-air-residual mixing within the piston bowl becomes important.

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“…The effect is deeper penetration of the fuel into the combustion chamber. In combination with slower vaporization, caused by the larger droplets, 17 this leads to a spatially spread and comparatively leaner stratification. Therefore, burn duration and HC and soot emissions are increased.…”

Section: Injection Pressures Up To 1000 Bar For Reducing Soot and Particulate Matter Emissionsmentioning

confidence: 99%

“…This technology is presently the focus of research and development activities. 2,3,7 Future concepts to increase engine efficiency will combine different technologies such as direct fuel injection, boosting and variable valve actuation.…”

Section: Introductionmentioning

confidence: 99%

Potential of spray-guided gasoline direct injection for reduction of fuel consumption and simultaneous compliance with stricter emissions regulations

Schumann

Sarikoc

Buri

et al. 2012

International Journal of Engine Research

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The combination of gasoline direct injection and turbocharging is a promising method to reduce the fuel consumption of internal combustion engines through engine downsizing, which leads to increased engine efficiencies and a reduction of CO2 emissions at a comparable power output. Spray-guided direct injection allows overall lean and unthrottled operation, which is realized with a highly stratified mixture at part load. However, exhaust gas aftertreatment with conventional three-way catalysts is currently not possible. Furthermore, insufficient mixture preparation, especially at the upper load limit of stratified charge operation, causes increased particulate matter emissions. This paper discusses the advantages of engine downsizing, by gasoline direct injection in combination with turbocharging, to reduce fuel consumption and presents the results of experimental and numerical investigations of stratified exhaust gas recirculation in a single-cylinder gasoline engine to reduce nitrogen oxide emissions. The radial exhaust gas stratification was achieved by a spatial and temporal separated induction of exhaust gas and fresh air, performed by specially shaped baffles and impulse charge valves in the inlet port. The thermodynamic and optical investigations with injection pressures up to 1000 bar demonstrate the capability to reduce soot emissions in a spray-guided direct-injection engine.

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High Injection Pressures at the Upper Load Limit of Stratified Operation in a DISI Engine

Cited by 23 publications

References 3 publications

Friction and wear behaviour of silicon carbide/graphene composites under isooctane lubrication

Friction and wear behaviour of silicon carbide/graphene composites under isooctane lubrication

Invited Review: Combustion instability in spray-guided stratified-charge engines: A review

Potential of spray-guided gasoline direct injection for reduction of fuel consumption and simultaneous compliance with stricter emissions regulations

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