The SAE MOBILUS platform will continue to be accessible and populated with high quality technical content during the coronavirus (COVID-19) pandemic. x

Your Selections

Wooldridge, Margaret
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Events

   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Dual Fuel Injection (DI + PFI) for Knock and EGR Dilution Limit Extension in a Boosted SI Engine

University of Michigan-Taehoon Han, George Lavoie, Margaret Wooldridge, André Boehman
Published 2018-09-10 by SAE International in United States
Combined direct and port fuel injection (i.e., dual injection) in spark ignition engines is of increasing interest due to the advantages for fuel flexibility and the individual merits of each system for improving engine performance and reducing engine-out emissions. Greater understanding of the impact of dual injection will enable deriving the maximum benefit from the two injection systems. This study investigates the effects of dual injection on combustion, especially knock propensity and tolerance to exhaust gas recirculation (EGR) dilution at different levels of EGR. A baseline for comparison with dual injection results was made using direct injection fueling only. A splash blended E20 fuel was used for the direct injection only tests. For the dual injection tests, gasoline, representing 80% by volume of the total fuel, was injected using the direct injector, and ethanol, representing 20% by volume of the total fuel, was injected using the port fuel injector. EGR mass fraction was varied from 0% to 21%, under boosted intake air pressure of 1.25 bar for both injection strategies. The results showed dual injection…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Effects of Engine Speed on Spray Behaviors of the Engine Combustion Network “Spray G” Gasoline Injector

Robert Bosch LLC-Mohammad Fatouraie
University of Melbourne-Joshua Lacey, Michael Brear
Published 2018-04-03 by SAE International in United States
Non-reacting spray behaviors of the Engine Combustion Network “Spray G” gasoline fuel injector were investigated at flash and non-flash boiling conditions in an optically accessible single cylinder engine and a constant volume spray chamber. High-speed Mie-scattering imaging was used to determine transient liquid-phase spray penetration distances and observe general spray behaviors. The standardized “G2” and “G3” test conditions recommended by the Engine Combustion Network were matched in this work and the fuel was pure iso-octane. Results from the constant volume chamber represented the zero (stationary piston) engine speed condition and single cylinder engine speeds ranged from 300 to 2,000 RPM. As expected, the present results indicated the general spray behaviors differed significantly between the spray chamber and engine. The differences must be thoughtfully considered when applying spray chamber results to guide spray model development for engine applications. Overall, increases in engine speed correlated well with enhanced vaporization, loss of distinct plume structure, and enhanced spray collapse which led to reductions in wetted-footprint area. Furthermore, while loss of distinct plume structures appeared to be strongly dependent…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

High-Speed Imaging Studies of Gasoline Fuel Sprays at Fuel Injection Pressures from 300 to 1500 bar

Robert Bosch LLC-Mohammad Fatouraie
University of Michigan-Mario Medina, Margaret Wooldridge
Published 2018-04-03 by SAE International in United States
High-pressure gasoline fuel injection is a means to improve combustion efficiency and lower engine-out emissions. The objective of this study was to quantify the effects of fuel injection pressure on transient gasoline fuel spray development for a wide range of injection pressures, including over 1000 bar, using a constant volume chamber and high-speed imaging. Reference grade gasoline was injected at fuel pressures of 300, 600, 900, 1200, and 1500 bar into the chamber, which was pressurized with nitrogen at 1, 5, 10, and 20 bar at room temperature (298 K). Bulk spray imaging data were used to quantify spray tip penetration distance, rate of spray tip penetration and spray cone angle. Near-nozzle data were used to evaluate the early spray development.The bulk characteristics of the high pressure gasoline sprays were consistent with trends previously observed at lower fuel injection pressures, e.g. spray tip penetration distance increased with increased fuel injection pressure after the spray break-up time and sprays with higher cone angles were produced with increasing chamber pressure at constant fuel injection pressure. The spray break-up time was a…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Effects of Fuel Injection Events of Ethanol and Gasoline Blends on Boosted Direct-Injection Engine Performance

University of Michigan-Ripudaman Singh, Travis Burch, George Lavoie, Margaret Wooldridge, Mohammad Fatouraie
Published 2017-10-08 by SAE International in United States
Numerous studies have demonstrated the benefits of ethanol in increasing the thermal efficiency of gasoline-fueled spark ignition engines via the higher enthalpy of vaporization and higher knock resistance of ethanol compared with gasoline. This study expands on previous work by considering a split fuel injection strategy with a boosted direct injection spark ignition engine fueled with E0 (100% by volume reference grade gasoline; with research octane number = 91 and motor octane number = 83), E100 (100% by volume anhydrous ethanol), and various splash-blends of the two fuels. Experiments were performed using a production 3-cylinder Ford Ecoboost engine where two cylinders were de-activated to create a single-cylinder engine with a displacement of 0.33 L. The engine was operated over a range of loads with boosted intake manifold absolute pressure (MAP) from 1 bar to 1.5 bar. The fuel injection timing of single fuel injection events was varied at MAP = 1 bar using different blend ratios (E0, E30, E50, E85 and E100) to identify the range of injection timing corresponding to maximum thermal efficiency for…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Effect of Syngas (H2/CO) on SI Engine Knock under Boosted EGR and Lean Conditions

SAE International Journal of Engines

University of Michigan-Taehoon Han, George Lavoie, Margaret Wooldridge, André Boehman
  • Journal Article
  • 2017-01-0670
Published 2017-03-28 by SAE International in United States
Syngas (synthesis gas) aided combustion from various fuel reforming strategies is of increasing interest in boosted lean burn SI engines due to its impact on dilution tolerance and knock resistance. Due to the interest in reformed fuels, more concrete understanding of how to leverage syngas supplementation under various lean conditions is essential to optimize engine performance and derive the most benefit from the availability of syngas in the combustion process. While the impact of syngas supplementation on combustion stability has been studied adequately, detailed understanding of the impact of syngas on knocking is still limited. Hence, this study investigates the effect of syngas (H2/CO) addition on knock tendency under boosted EGR (Exhaust Gas Recirculation) and air diluted conditions. Syngas amount is controlled on an energy basis from 0% to 15% to compare the difference between EGR and air dilution. At first, several knock quantification methods are compared, and a suitable knock index and guideline are selected. Knocking tendencies with respect to the frequency, combustion phasing, and burn duration are analyzed based on observed engine knock.…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Computational Development of a Dual Pre-Chamber Engine Concept for Lean Burn Combustion

Hyundai-Kia America Technical Center Inc-Nayan Engineer, Paul Neuman
University of Michigan-Dimitris Assanis, Margaret Wooldridge
Published 2016-10-17 by SAE International in United States
Pre-chambers are a means to enable lean burn combustion strategies which can increase the thermal efficiency of gasoline spark ignition internal combustion engines. A new engine concept is evaluated in this work using computational simulations of non-reacting flow. The objective of the computational study was to evaluate the feasibility of several engine design configurations combined with fuel injection strategies to create local fuel/air mixtures in the pre-chambers above the ignition and flammability limits, while maintaining lean conditions in the main combustion chamber. The current work used computational fluid dynamics to develop a novel combustion chamber geometry where the flow was evaluated through a series of six design iterations to create ignitable mixtures (based on fuel-to-air equivalence ratio, ϕ) using fuel injection profiles and flow control via the piston, cylinder head, and pre-chamber geometry. The desirable and undesirable features that guided the design progression are presented. Major combustion chamber design iterations involved changes to the pre-chambers position relative to the cylinder head deck plane, azimuthal orientation of the pre-chambers, and piston crown geometry. Further criteria were…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Highly Turbocharged Gasoline Engine and Rapid Compression Machine Studies of Super-Knock

SAE International Journal of Engines

Chery Automobile Co., Ltd.-Zhichao Jia, Mengke Wang
Tsinghua University-Hui Liu, Zhi Wang, Yunliang Qi, Xin He, Jian-Xin Wang
  • Journal Article
  • 2016-01-0686
Published 2016-04-05 by SAE International in United States
Super-knock has been a significant obstacle for the development of highly turbocharged (downsized) gasoline engines with spark ignition, due to the catastrophic damage super-knock can cause to the engine. According to previous research by the authors, one combustion process leading to super-knock may be described as hot-spot induced pre-ignition followed by deflagration which can induce detonation from another hot spot followed by high pressure oscillation. The sources of the hot spots which lead to pre-ignition (including oil films, deposits, gas-dynamics, etc.) may occur sporadically, which leads to super-knock occurring randomly at practical engine operating conditions. In this study, a spark plasma was used to induce preignition and the correlation between super-knock combustion and the thermodynamic state of the reactant mixture was investigated in a four-cylinder production gasoline engine. The engine experiments were complemented by rapid compression machine (RCM) experiments of iso-octane and air which also used a spark plasma to investigate the fundamental physical and chemical mechanisms of super-knock. For the engine experiments, at low-speed high-load conditions, early spark timing was used to systematically induce…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Extending the Dilution Limit of Spark Ignition Combustion via Fuel Injection during Negative Valve Overlap

University of Michigan-Yan Chang, Margaret Wooldridge, Stanislav V. Bohac
Published 2016-04-05 by SAE International in United States
Using exhaust gas recirculation (EGR) as a diluent instead of air allows the use of a conventional three-way catalyst for effective emissions reduction. Cooled EGR can also reduce fuel consumption and NOx emissions, but too much cool EGR leads to combustion instability and misfire. Negative valve overlap (NVO) is explored in the current work as an alternative method of dilution in which early exhaust valve closing causes combustion products to be retained in the cylinder and recompressed near top dead center, before being mixed with fresh charge during the intake stroke. The potential for fuel injection during NVO to extend the dilution limit of spark ignition combustion is evaluated in this work using experiments conducted on a 4-cylinder 2.0 L gasoline direct injection engine with variable intake and exhaust valve timing. The results demonstrate fuel injection during NVO can extend the dilution limit, improve brake specific fuel consumption (BSFC), and reduce CO and NOx emissions. Specifically, 80 CAD of NVO with start of fuel injection at top dead center allowed the use of 32% total…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Hydrogen DI Dual Zone Combustion System

SAE International Journal of Engines

Ford Motor Co.-Brad Boyer
University of Michigan-Margaret Wooldridge
  • Journal Article
  • 2013-01-0230
Published 2013-04-08 by SAE International in United States
Internal combustion (IC) engines fueled by hydrogen are among the most efficient means of converting chemical energy to mechanical work. The exhaust has near-zero carbon-based emissions, and the engines can be operated in a manner in which pollutants are minimal. In addition, in automotive applications, hydrogen engines have the potential for efficiencies higher than fuel cells.[1] In addition, hydrogen engines are likely to have a small increase in engine costs compared to conventionally fueled engines. However, there are challenges to using hydrogen in IC engines. In particular, efficient combustion of hydrogen in engines produces nitrogen oxides (NOx) that generally cannot be treated with conventional three-way catalysts.This work presents the results of experiments which consider changes in direct injection hydrogen engine design to improve engine performance, consisting primarily of engine efficiency and NOx emissions. Two cylinder head configurations and two fuel injector designs were considered. One cylinder head used central spark ignition and the other used dual side spark ignition. One fuel injector used a symmetric geometry of five holes (5H, a central hole with 4…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Direct In-cylinder Injection of Water into a PI Hydrogen Engine

Ford Motor Co.-Brad Boyer
University of Michigan-Margaret Wooldridge
Published 2013-04-08 by SAE International in United States
Injecting liquid water into a fuel/air charge is a means to reduce NOx emissions. Such strategies are particularly important to hydrogen internal combustion engines, as engine performance (e.g., maximum load) can be limited by regulatory limits on NOx. Experiments were conducted in this study to quantify the effects of direct injection of water into the combustion chamber of a port-fueled, hydrogen IC engine. The effects of DI water injection on NOx emissions, load, and engine efficiency were determined for a broad range of water injection timing. The amount of water injected was varied, and the results were compared with baseline data where no water injection was used. Water injection was a very effective means to reduce NOx emissions. Direct injection of water into the cylinder reduced NOx emissions by 95% with an 8% fuel consumption penalty, and NOx emissions were reduced by 85% without any fuel consumption penalty.
Annotation ability available