Tracer-LIF diagnostics: quantitative measurement of fuel concentration, temperature and fuel/air ratio in practical combustion systems

Knocking combustion in spark-ignition engines

Smoothing HCCI Heat-Release Rates Using Partial Fuel Stratification with Two-Stage Ignition Fuels

This study explores the influence of ethanol on particulate matter (PM) emissions from gasoline direct injection (GDI) vehicles, a technology introduced to improve fuel economy and lower CO2 emissions, but facing challenges to meet next-generation emissions standards. Because PM formation in GDI engines is sensitive to a number of operating parameters, two engine calibrations are examined to gauge the robustness of the results. As the ethanol level in gasoline increases from 0% to 20%, there is possibly a small ( 30%, there is a statistically significant 30%–45% reduction in PM mass and number emissions observed for both engine calibrations. Particle size is unaffected by ethanol level. PM composition is primarily elemental carbon; the organic fraction increases from ∼5% for E0 to 15% for E45 fuel. Engine-out hydrocarbon and NOx emissions exhibit 10–20% decreases, consistent w...

https://www.tandfonline.com/doi/pdf/10.1080/02786826.2011.648780

The Impact of Ethanol Fuel Blends on PM Emissions from a Light-Duty GDI Vehicle

Light-duty vehicles (LDVs) in the United States and elsewhere are required to meet increasingly challenging regulations on fuel economy and greenhouse gas (GHG) emissions as well as criteria pollutant emissions. New vehicle trends to improve efficiency include higher compression ratio, downsizing, turbocharging, downspeeding, and hybridization, each involving greater operation of spark-ignited (SI) engines under higher-load, knock-limited conditions. Higher octane ratings for regular-grade gasoline (with greater knock resistance) are an enabler for these technologies. This literature review discusses both fuel and engine factors affecting knock resistance and their contribution to higher engine efficiency and lower tailpipe CO2 emissions. Increasing compression ratios for future SI engines would be the primary response to a significant increase in fuel octane ratings. Existing LDVs would see more advanced spark timing and more efficient combustion phasing. Higher ethanol content is one available option for increasing the octane ratings of gasoline and would provide additional engine efficiency benefits for part and full load operation. An empirical calculation method is provided that allows estimation of expected vehicle efficiency, volumetric fuel economy, and CO2 emission benefits for future LDVs through higher compression ratios for different assumptions on fuel properties and engine types. Accurate "tank-to-wheel" estimates of this type are necessary for "well-to-wheel" analyses of increased gasoline octane ratings in the context of light duty vehicle transportation.

The Effect of Compression Ratio, Fuel Octane Rating, and Ethanol Content on Spark-Ignition Engine Efficiency

Development and Optimization of the Ford 3.5L V6 EcoBoost Combustion System

Comparison of Analytically and Experimentally Obtained Residual Fractions and NOX Emissions in Spark-Ignited Engines

A new Light Stratified-Charge Direct Injection (LSC Dl) spark ignition combustion system concept was developed at Ford. One of the new features of the LSC Dl concept is to use a 'light' stratified-charge operation window ranging from the idle operation to low speed and low load. A dual independent variable cam timing (DiVCT) mechanism is used to increase the internal dilution for emissions control and to improve engine thermal efficiency. The LSC Dl concept allows a large relaxation in the requirement for the lean after-treatment system, but still enables significant fuel economy gains over the PFI base design, delivering high technology value to the customer. In addition, the reduced stratified-charge window permits a simple, shallow piston bowl design that not only benefits engine wide-open throttle performance, but also reduces design compromises due to compression ratio, DiVCT range and piston bowl shape constraints.

Development of a new light stratified-charge DISI combustion system for a family of engines with upfront CFD coupling with thermal and optical engine experiments

A method for improving turbocharger waste-gate control is presented. The method can reduce turbocharger flow oscillation, at least during some conditions.

Turbocharger waste gate control

Spray angle and penetration length data were taken under cold start conditions for a Direct Injection Spark Ignition engine to investigate the effect of transient conditions on spray development. The results show that during cold start, spray development depends primarily on fuel pressure, followed by Manifold Absolute Pressure (MAP). Injection frequency had little effect on spray development. The spray for this single hole, pressure-swirl fuel injector was characterized using high speed imaging. The fuel spray was characterized by three different regimes. Regime 1 comprised fuel pressures from 6 ? 13 bar, MAPs from 0.7 ? 1 bar, and was characterized by a large pre-spray along with large drop sizes. The spray angle and penetration lengths were comparatively small. Regime 2 comprised fuel pressures from 30 ? 39 bar and MAPs from 0.51 ? 0.54 bar. A large pre-spray and large drop sizes were still present but reduced compared to Regime 1. The spray angle and penetration lengths were typically larger then in Regime 1. Regime 3 comprised fuel pressures from 65 ? 102 bar and MAPs from 0.36 ? 0.46 bar. The fuel spray had a fully developed hollow cone structure with recirculation vortices at the edges of the spray, which constricted the spray angle. The spray angle was similar to Regime 2, while the penetration length increased. The pre-spray and drop size were reduced compared to Regime 2. In all regimes, decreasing MAP enlarged the spray angle, while injection frequency was not a significant factor.

/pdf/spray-characterization-in-a-disi-engine-during-cold-start-2-2hzni2rgqc.pdf

Corey Weaver

Papers

Development and Optimization of the Ford 3.5L V6 EcoBoost Combustion System

Comparison of Analytically and Experimentally Obtained Residual Fractions and NOX Emissions in Spark-Ignited Engines

Development of a new light stratified-charge DISI combustion system for a family of engines with upfront CFD coupling with thermal and optical engine experiments

Turbocharger waste gate control

Spray Characterization in a DISI Engine During Cold Start: (2) PDPA Investigation