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Study of fuel octane sensitivity effects on gasoline partially premixed combustion using optical diagnostics

Kaust-Hao Shi
King Abdullah Univ of Science & Tech-Yanzhao An, Bengt Johansson
  • Technical Paper
  • 2019-24-0025
To be published on 2019-08-15 by SAE International in United States
Partially premixed combustion (PPC) is a low-temperature combustion (LTC) concept that could deliver higher engine efficiency, as well as lower NOx and soot emissions. Gasoline-like fuels are beneficial for air/fuel mixing process under PPC mode because they have superior auto-ignition resistance to prolong ignition delay time. In current experiments, the high octane number gasoline fuel E10 (US market used gasoline, RON=91) and low octane number GCI blend fuel (RON=77) were tested respectively in a full-transparent AVL single cylinder optical compression ignition (CI) engine. Aiming at investigating the fuel sensitivity on engine performances under different combustion modes as well as soot particle emissions, the engine operating parameters and emission data were analyzed from CI to HCCI (homogeneous charge compression ignition) via PPC (partially premixed combustion) by changing fuel injection timing. In addition, in order to get a deep insight of in-cylinder auto-ignition and combustion evolution process, planar laser-induced fluorescence (PLIF) imaging and high-speed natural flame luminosity (NFL) imaging techniques are used for visualizing fuel distribution, auto-ignition kernel development and combustion processes.

Optimization of Multi Stage Direct Injection-PSCCI Engines

Università degli Studi della Basilicata-Annarita Viggiano, Vinicio Magi
  • Technical Paper
  • 2019-24-0029
To be published on 2019-08-15 by SAE International in United States
The more stringent regulations on emissions induce the automotive companies to develop new solutions for engine design, including the use of advanced combustion strategies and the employment of mixture of fuels with different thermochemical properties. The HCCI combustion coupled with the partial direct injection of the charge, in order to control the performance and emissions and to extend the operating range, is a promising technique. In this work an in-house developed multi-dimensional CFD software package was used to analyse the behaviour of a multi stage direct injection (DI)-partially stratified charge compression ignition engine fueled with PRF. A skeletal kinetic mechanism for PRF oxidation was employed, with a dynamic adaptive chemistry technique to reduce the computational cost and a model based on the partially stirred reactor model to couple turbulence and chemistry. Most of the fuel was injected during the intake stroke, in order to get a homogeneous mixture of fuel and air, whereas the remaining part was injected at the end of the compression stroke, in order to stratify the fuel and temperature distributions in…

A Review of Spark-Assisted Compression Ignition (SACI) Research in the Context of Realizing a Production SACI Strategy

Clemson Univ-Robert Prucka
Clemson Univ.-Dennis Robertson
  • Technical Paper
  • 2019-24-0027
To be published on 2019-08-15 by SAE International in United States
Low temperature combustion (LTC) strategies have been a keen interest in the automotive industry for over four decades since they offer improved fuel efficiency compared to conventional spark-ignition (SI) engines. LTC strategies use high dilution to keep combustion temperatures below about 2000 K to reduce heat transfer losses while avoiding locally rich in-cylinder regions that produce high soot. High dilution also enables an efficiency improvement from reduced pumping work and improved thermodynamic properties, though it requires high ignition energy. Combustion can be achieved by triggering autoignition from compression energy. High compression ratios are typically required to produce this level of ignition energy, which further improves fuel efficiency. The timing of the autoignition event is influenced by fuel properties and mixture composition, and is exponentially sensitive to temperature. Control of autoignition timing is difficult without a direct actuator, and has been a significant obstacle for realizing LTC in production. Spark-assisted compression ignition (SACI) addresses this challenge by using a spark plug to initiate chemical reactions that trigger autoignition. The combustion chamber is slightly stratified to promote…

Sensitivity Analysis of the Combustion Parameters in a Stratified HCCI Engine with Regard to Performance and Emission

mahboud Armin
Mazandaran university of science and tec-Mohsen Pourfallah
  • Technical Paper
  • 2019-24-0114
To be published on 2019-08-15 by SAE International in United States
Homogeneous charge compression ignition (HCCI) is a promised solution to environmental and fuel economy concerns for IC engines. Engine application for HCCI engine depends on an array of parameters such as fuel type, mixture composition, intake condition and engine specification, meaning that controlling an HCCI engine can only be done through the adjustment of these parameters. In this numerical study which is driven from an experimental work, thermal and charge stratification is used to control HCCI combustion. The effect of intake temperature, compression ratio, intake pressure, EGR, reformer gas (CO-H2 mixture) and glow plug temperature on engine performance and emission was investigated using a 3D model on AVL-FIRE parallel with 1D model on GT-Power software. Then AHP model as a multiple Attribute Decision making method has been used to analyze the sensitivity of these parameters on performance and emission. Results indicate that increasing intake temperature causes the operating condition approaches knock which results in a narrower operating region. Increasing EGR ratio makes possible the expanding of operating range rich limit since it causes delayed combustion…

HCCI with Wet Ethanol: Investigating the Charge Cooling Effect of a High Latent Heat of Vaporization Fuel.

Stony Brook Univ.-Brian Gainey, James Gohn, Ziming Yan, Khurram Malik, Mozhgan Rahimi Boldaji, Benjamin Lawler
  • Technical Paper
  • 2019-24-0024
To be published on 2019-08-15 by SAE International in United States
The combustion phasing of Homogeneous Charge Compression Ignition combustion is incredibly sensitive to intake temperature. Controlling the intake temperature on a cycle-to-cycle basis is one-way control combustion phasing, however accomplishing this with an intake air heater/intercooler is unfeasible. One possible way to control the intake temperature is through the direct injection of fuel. The direct injection of fuel during the intake stroke cools the charge via evaporative cooling. Some heat is absorbed from the incoming air, lowering the in-cylinder temperature, while some heat is absorbed from the piston/cylinder walls if the spray reaches the walls. The amount of heat that is absorbed from the air vs. the walls depends on the injection timing during the intake. Therefore, if a high latent heat of vaporization fuel is used, the intake temperature will become very sensitive to injection timing, allowing for cycle-to-cycle control of combustion phasing. Ethanol is a fuel with a high latent heat of vaporization and therefore possesses a large charge cooling potential. Wet ethanol, a mixture of ethanol and water, offers an even higher…

On the HCCI octane boosting effects of γ-Valerolactone

King Abdullah Univ. of Science & Tech.-Jean-Baptiste Masurier, Binod Giri, Gani Issayev, Bengt Johansson, Aamir Farooq PhD
  • Technical Paper
  • 2019-24-0026
To be published on 2019-08-15 by SAE International in United States
Transportation sector is almost entirely powered by internal combustion engines (ICEs) burning petroleum-based liquid fuels. This makes the transportation sector the main culprit of global warming due to the large quantity of CO2 emission from burning these petroleum-based fuels. Over the last few decades, there are growing concerns over global warming and diminishing petroleum reserves. Such concerns have led to concentrated efforts directed at a paradigm shift from conventional fuels to renewable alternatives which can promote cleaner combustion. Therefore, future research directions should orient towards exploring new fuels suitable for future ICEs to achieve better engine efficiency and significantly less harmful emissions. One way to achieve these objectives is to focus on improving the combustion technology by developing new fuel-engine systems. Consequently, scientists and engineers are showing growing interest towards non-petroleum-based fuels coming from renewable resources. Among bio-derived fuels, γ-Valerolactone (GVL), a fuel derived from lignocellulosic biomass, has recently attracted considerable attention due to its potential for increasing the octane number and reducing harmful emissions. This study aims to examine GVL as an octane booster…

Mazda finally ready with Skyactiv-D for U.S.

Automotive Engineering: June 2019

Paul Seredynski
  • Magazine Article
  • 19AUTP06_14
Published 2019-06-01 by SAE International in United States

Mazda announced the long-awaited arrival of its Skyactiv-D diesel engine to the U.S. at April's New York International Auto Show. The 2.2L twin-sequential turbocharged 4-cylinder diesel is available for pre-order now in the highest AWD trim of Mazda's best-selling vehicle, the 2-row, 5-seat Mazda CX-5 SUV. The 2019 model with the diesel engine has a starting MSRP of $41,000-a $4K premium over the equivalent gasoline trim-with deliveries expected to begin this summer.

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TSCI with Wet Ethanol: An Investigation of the Effects of Injection Strategy on a Diesel Engine Architecture

SUNY-Stonybrook-Ziming Yan
Stony Brook University-Brian Gainey, James Gohn, Mozhgan Rahimi Boldaji, Benjamin Lawler
Published 2019-04-02 by SAE International in United States
Thermally Stratified Compressions Ignition (TSCI) is a new advanced, low temperature combustion concept that aims to control the thermal stratification in the cylinder in order to control the heat release process in a lean, compression-ignition combustion mode. This work uses “wet ethanol”, a mixture of 80% ethanol and 20% water by mass, to increase thermal stratification beyond what naturally occurs, via evaporative cooling of a split direct injection. TSCI with wet ethanol has previously shown the potential to increase the high-load limit when compared to HCCI. The experiments conducted in this paper aim to fundamentally understand the effect that injection strategy has on the heat release process in TSCI.TSCI employs a split-injection strategy in which an injection during the intake stroke allows the majority of the fuel to premix with the air and an injection during the compression stroke introduces the desired level of thermal stratification to control the heat release rate. A single injection at -350 deg aTDC was found to be the most effective way to inject fuel during the intake stroke. The…
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The Physical and Chemical Effects of Fuel on Gasoline Compression Ignition

King Abdullah University of Science & Technology-R. Vallinayagam, Ponnya Hlaing, Abdullah S. AlRamadan, Yanzhao An, Bengt Johansson
Saudi Aramco-Jaeheon Sim, Junseok Chang
Published 2019-04-02 by SAE International in United States
In the engine community, gasoline compression ignition (GCI) engines are at the forefront of research and efforts are being taken to commercialize an optimized GCI engine in the near future. GCI engines are operated typically at Partially Premixed Combustion (PPC) mode as it offers better control of combustion with improved combustion stability. While the transition in combustion homogeneity from convectional Compression Ignition (CI) to Homogenized Charge Compression Ignition (HCCI) combustion via PPC has been comprehensively investigated, the physical and chemical effects of fuel on GCI are rarely reported at different combustion modes. Therefore, in this study, the effect of physical and chemical properties of fuels on GCI is investigated. In-order to investigate the reported problem, low octane gasoline fuels with same RON = 70 but different physical properties and sensitivity (S) are chosen. Fuels with comparable sensitivity and RON are chosen to study the impact of physical properties on GCI. On the other hand, by keeping the same RON and physical properties, the effect of sensitivity on GCI is investigated. In this regard, three test…
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Triple Injection Strategies for Gasoline Compression Ignition (GCI) Combustion in a Single-Cylinder Small-Bore Common-Rail Diesel Engine

Imagineering Inc.-Yuji Ikeda
The University of New South Wales-Xinyu Liu, Harsh Goyal, Sanghoon Kook
Published 2019-04-02 by SAE International in United States
Implementing triple injection strategies in partially premixed charge-based gasoline compression ignition (GCI) engines has shown to achieve improved engine efficiency and reduced NOx and smoke emissions in many previous studies. While the impact of the triple injections on engine performance and engine-out emissions are well known, their role in controlling the mixture homogeneity and charge premixedness is currently poorly understood. The present study shows correspondence between the triple injection strategies and mixture homogeneity/premixedness through the experimental tests of second/third injection proportion and their timing variations with an aim to explain the observed GCI engine performance and emission trends. The experiments were conducted in a single cylinder, small-bore common-rail diesel engine fuelled with a commercial gasoline fuel of 95 research octane number (RON) and running at 2000 rpm and 830 kPa indicated mean effective pressure conditions. While the first injection proportion and timing were fixed at 40% and 170 °CA bTDC, the second injection proportion was varied between 5 and 20% (i.e. third injection of 40~55%) and the timing was varied from 20 to 80 °CA…
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