Your Selections

Shell Global Solutions
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.

Mechanism Analysis on the Effect of Fuel Properties on Knocking Performance at Boosted Conditions

Shell Global Solutions-Roger Cracknell
Nissan Motor Co., Ltd.-Masaharu Kassai, Cagdas Aksu, Taisuke Shiraishi
Published 2019-01-15 by SAE International in United States
In recent years, boosted and downsized engines have gained much attention as a promising technology to improve fuel economy; however, knocking is a common issue of such engines that requires attention.To understand the knocking phenomenon under downsized and boosted engine conditions deeply, fuels with different Research Octane Number (RON) and Motor Octane Number (MON) were prepared, and the knocking performances of these fuels were evaluated using a single cylinder engine, operated under a variety of conditions.Experimental results showed that the knocking performance at boosted conditions depend on both RON and MON. While higher RON showed better anti-knocking performance, lower MON showed better anti-knocking performance. Furthermore, the tendency for a reduced MON to be beneficial became stronger at lower engine speeds and higher boost pressures, in agreement with previously published modelling work.A new method of interpreting octane appetite is presented which relates the gradient of contour lines of MB50 in RON/MON space to K value.The results can be further interpreted by understanding the relative contribution of low temperature oxidation (LTO) pathways under the prevailing temperature/pressure conditions…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Octane Response of a Highly Boosted Direct Injection Spark Ignition Engine at Different Compression Ratios

Shell Global Solutions-Arjun Prakash, Jan-Hendrik Redmann, Roger Cracknell
Shell Global Solutions (US) Inc.-Allen A. Aradi
Published 2018-04-03 by SAE International in United States
Stringent regulations on fuel economy have driven major innovative changes in the internal combustion engine design. (E.g. CAFE fuel economy standards of 54.5 mpg by 2025 in the U.S) Vehicle manufacturers have implemented engine infrastructure changes such as downsizing, direct injection, higher compression ratios and turbo-charging/super-charging to achieve higher engine efficiencies. Fuel properties therefore, have to align with these engine changes in order to fully exploit the possible benefits. Fuel octane number is a key metric that enables high fuel efficiency in an engine. Greater resistance to auto-ignition (knock) of the fuel/air mixture allows engines to be operated at a higher compression ratio for a given quantity of intake charge without severely retarding the spark timing resulting in a greater torque per mass of fuel burnt. This attribute makes a high octane fuel a favorable hydrocarbon choice for modern high efficiency engines that aim for higher fuel economy. Prototype engine builds with novel design concepts allow for studying the impact of fuel octane number on engine performance: In this regard, a 2.0 L engine based on…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

A Study on the Effects of Cetane Number on the Energy Balance between Differently Sized Engines

Shell Global Solutions-Tushar K. Bera, Michael Parkes
Texas A&M University-Jue Li, Timothy J. Jacobs
Published 2017-03-28 by SAE International in United States
This paper investigates the effect of the cetane number (CN) of a diesel fuel on the energy balance between a light duty (1.9L) and medium duty (4.5L) diesel engine. The two engines have a similar stroke to bore (S/B) ratio, and all other control parameters including: geometric compression ratio, cylinder number, stroke, and combustion chamber, have been kept the same, meaning that only the displacement changes between the engine platforms. Two Coordinating Research Council (CRC) diesel fuels for advanced combustion engines (FACE) were studied. The two fuels were selected to have a similar distillation profile and aromatic content, but varying CN. The effects on the energy balance of the engines were considered at two operating conditions; a “low load” condition of 1500 rev/min (RPM) and nominally 1.88 bar brake mean effective pressure (BMEP), and a “medium load” condition of 1500 RPM and 5.65 BMEP. Results were recorded at the same crank angle 50% burn (CA50) condition to decouple fuel effects from engine effects. The results show that the CN of the fuel impacts the distribution…
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 Octane Number on the Performance of Euro 5 and Euro 6 Gasoline Passenger Cars

Shell Global Solutions-Andreas Kolbeck
BP International Ltd.-John Williams
Published 2017-03-28 by SAE International in United States
Research Octane Number (RON) and Motor Octane Number (MON) are used to describe gasoline combustion which describe antiknock performance under different conditions. Recent literature suggests that MON is less important than RON in modern cars and a relaxation in the MON specification could improve vehicle performance. At the same time, for the same octane number change, increasing RON appears to provide more benefit to engine power and acceleration than reducing MON. Some workers have advocated the use of an octane index (OI) which incorporates both parameters instead of either RON or MON to give an indication of gasoline knock resistance. Previous Concawe work investigated the effect of RON and MON on the power and acceleration performance of two Euro 4 gasoline passenger cars during an especially-designed acceleration test cycle. A large number of fuels blended with and without oxygenates and ranging from around 95 to 103 RON and sensitivities (RON minus MON) up to around 15 were tested. The results were vehicle dependent but in general, showed that sensitivity and octane index appear to be…
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 Properties Associated with In-Cylinder Behavior on Particulate Number from a Direct Injection Gasoline Engine

Shell Global Solutions-Andreas Kolbeck, Allen Aradi
Imperial College London-Sebastian Henkel, Yannis Hardalupas, Alexander Taylor
Published 2017-03-28 by SAE International in United States
The purpose of this work was to gain a fundamental understanding of which fuel property parameters are responsible for particulate emission characteristics, associated with key intermediate behavior in the engine cylinder such as the fuel film and insufficient mixing.Accordingly, engine tests were carried out using various fuels having different volatility and chemical compositions under different coolant temperature conditions. In addition, a fundamental spray and film visualization analysis was also conducted using a constant volume vessel, assuming the engine test conditions.As for the physical effects, the test results showed that a low volatility fuel displayed high particulate number (PN) emissions when the injection timing was advanced. The fundamental test clearly showed that the amount of fuel film on the impingement plate increased under such operating conditions with a low volatility fuel.Tests focusing on chemical effects with fuel blends having different aromatic and olefin contents were also conducted. The test results obtained under a completely vaporized condition showed that a test fuel with a high aromatic content displayed higher PN emissions under rich conditions than one with…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Octane Requirement and Efficiency in a Fleet of Modern Vehicles

Shell Global Solutions-Roger Cracknell
Shell Global Solutions GmbH-Jan-Hendrik Redmann, Maik Beutler
Published 2017-03-28 by SAE International in United States
In light of increasingly stringent CO2 emission targets, Original Equipment Manufacturers (OEM) have been driven to develop engines which deliver improved combustion efficiency and reduce energy losses. In spark ignition engines one strategy which can be used to reach this goal is the full utilization of fuel octane number.Octane number is the fuel´s knock resistance and is characterized as research octane number (RON) and motor octane number (MON). Engine knock is caused by the undesired self-ignition of the fuel air mixture ahead of the flame front initiated by the spark. It leads to pressure fluctuations that can severely damage the engine. Modern vehicles utilize different strategies to avoid knock. One extreme strategy assumes a weak fuel quality and, to protect the engine, retards the spark timing at the expense of combustion efficiency. The other extreme carefully detects knock in every engine cycle and retards the spark timing only when knock is detected. Therefore as fuel octane number improves, the spark is advanced to the knock boundary of that fuel; a process known as knock limited…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Injector Fouling and Its Impact on Engine Emissions and Spray Characteristics in Gasoline Direct Injection Engines

SAE International Journal of Fuels and Lubricants

Shell Global Solutions-Christopher Conifer, Roger Cracknell, Tor Kit Goh
IAV GmbH, Germany-Paul-Benjamin Reinicke, Marc Sens, Michael Rieß
  • Journal Article
  • 2017-01-0808
Published 2017-03-28 by SAE International in United States
In Gasoline Direct Injection engines, direct exposure of the injector to the flame can cause combustion products to accumulate on the nozzle, which can result in increased particulate emissions. This research observes the impact of injector fouling on particulate emissions and the associated injector spray pattern and shows how both can be reversed by utilising fuel detergency. For this purpose multi-hole injectors were deliberately fouled in a four-cylinder test engine with two different base fuels. During a four hour injector fouling cycle particulate numbers (PN) increased by up to two orders of magnitude. The drift could be reversed by switching to a fuel blend that contained a detergent additive. In addition, it was possible to completely avoid any PN increase, when the detergent containing fuel was used from the beginning of the test. Microscopy showed that increased injector fouling coincided with increased particulate emissions. Based on these results a selection of the injectors was installed in a laboratory injection chamber and the spray patterns were investigated with a high speed camera. Injectors corresponding to the…
This content contains downloadable datasets
Annotation ability available
Open Access

Impact of Fuel Sensitivity (RON-MON) on Engine Efficiency

SAE International Journal of Fuels and Lubricants

Shell Global Solutions-Arjun Prakash, Chongming Wang, Andreas Janssen, Allen Aradi, Roger Cracknell
  • Journal Article
  • 2017-01-0799
Published 2017-03-28 by SAE International in United States
Modern spark ignition engines can take advantage of better fuel octane quality either towards improving acceleration performance or fuel economy via an active ignition management system. Higher fuel octane allows for spark timing advance and consequently higher torque output and higher engine efficiency. Additionally, engines can be designed with higher compression ratios if a higher anti-knock quality fuel is used. Due to historical reasons, Research Octane (RON) and Motor Octane Number (MON) are the metrics used to characterize the anti-knock quality of a fuel. The test conditions used to compute RON and MON correlated well with those in older engines designed about 20 years ago. But the correlation has drifted considerably in the recent past due to advances in engine infrastructures mainly governed by stringent fuel economy and emission standards. In prior research, the octane response of modern engines seemed to correlate better with RON than MON; however, the impact of octane sensitivity (RON-MON) has not been evaluated in detail. In this study, the aforementioned relationship between engine octane appetite and octane sensitivity was studied…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Effect of Diesel Properties on Emissions and Fuel Consumption from Euro 4, 5 and 6 European Passenger Cars

Shell Global Solutions-Rod Williams, Peter J Zemroch
Aristotle University of Thessaloniki-Zissis Samaras, Athanasios Dimaratos
Published 2016-10-17 by SAE International in United States
Certain diesel fuel specification properties are considered to be environmental parameters according to the European Fuels Quality Directive (FQD, 2009/EC/30) and previous regulations. These limits included in the EN 590 specification were derived from the European Programme on Emissions, Fuels and Engine Technologies (EPEFE) which was carried out in the 1990’s on diesel vehicles meeting Euro 2 emissions standards. These limits could potentially constrain FAME blending levels higher than 7% v/v. In addition, no significant work has been conducted since to investigate whether relaxing these limits would give rise to performance or emissions debits or fuel consumption benefits in more modern vehicles. The objective of this test programme was to evaluate the impact of specific diesel properties on emissions and fuel consumption in Euro 4, Euro 5 and Euro 6 light-duty diesel vehicle technologies. The tests were conducted in two driving cycles, the New European Driving Cycle (NEDC) and the Worldwide harmonised Light duty Test Cycle (WLTC), which is considered closer to real driving and is going to be the new type approval test in…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

An Optical Characterization of Atomization in Non-Evaporating Diesel Sprays

Shell Global Solutions-Richard Price
City University London-R. Lockett, Kassandra Makri
Published 2016-04-05 by SAE International in United States
High-speed planar laser Mie scattering and Laser Induced Fluorescence (PLIF) were employed for the determination of Sauter Mean Diameter (SMD) distribution in non-evaporating diesel sprays. The effect of rail pressure, distillation profile, and consequent fuel viscosity on the drop size distribution developing during primary and secondary atomization was investigated. Samples of conventional crude-oil derived middle-distillate diesel and light distillate kerosene were delivered into an optically accessible mini-sac injector, using a customized high-pressure common rail diesel fuel injection system. Two optical channels were employed to capture images of elastic Mie and inelastic LIF scattering simultaneously on a high-speed video camera at 10 kHz. Results are presented for sprays obtained at maximum needle lift during the injection. These reveal that the emergent sprays exhibit axial asymmetry and vorticity. An increase in the rail pressure was observed to lead to finer atomization, with larger droplets observable in the neighbourhood of the central axis of the spray, decreasing with radius towards the spray boundaries. Finally, the light kerosene was observed to produce smaller droplets (as measured by Sauter mean…
Annotation ability available