scholarly journals Auto-Ignition and Spray Characteristics of n-Heptane and iso-Octane Fuels in Ignition Quality Tester

2018 ◽  
Author(s):  
Mohammed Jaasim Mubarak Ali ◽  
Ayman Elhagrasy ◽  
Mani Sarathy ◽  
Sukho Chung ◽  
Hong G. Im
Keyword(s):  
Spray Characteristics ◽  
Auto Ignition ◽  
Ignition Quality ◽  
Ignition Quality Tester

An Investigation on Sensitivity of Ignition Delay and Activation Energy in Diesel Combustion

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Umashankar Joshi ◽  
Ziliang Zheng ◽  
Amit Shrestha ◽  
Naeim Henein ◽  
Eric Sattler
Keyword(s):  
Activation Energy ◽  
Ignition Delay ◽  
Cetane Number ◽  
Ignition Process ◽  
Start Of Injection ◽  
Auto Ignition ◽  
Time Period ◽  
Ignition Quality ◽  
Ignition Quality Tester ◽  
Start Of Combustion

The auto-ignition process plays a major role in the combustion, performance, fuel economy, and emission in diesel engines. The auto-ignition quality of different fuels has been rated by its cetane number (CN) determined in the cooperative fuel research engine, according to ASTM D613. More recently, the ignition quality tester (IQT), a constant volume vessel, has been used to determine the derived cetane number (DCN) to avoid the elaborate, time consuming, and costly engine tests, according to ASTM D6890. The ignition delay (ID) period in these two standard tests and many investigations has been considered to be the time period between start of injection (SOI) and start of combustion (SOC). The ID values determined in different investigations can vary due to differences in instrumentation and definitions. This paper examines the different definitions and the parameters that effect ID period. In addition, the activation energy dependence on the ID definition is investigated. Furthermore, results of an experimental investigation in a single-cylinder research diesel engine will be presented, while the charge density is kept constant during the ID period. The global activation energy is determined and its sensitivity to the charge temperature is examined.

Experimental Validation of a Three-Component Surrogate for Sasol-Isoparaffinic Kerosene in Single Cylinder Diesel Engine and Ignition Quality Tester

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Samy Alkhayat ◽  
Manan Trivedi ◽  
Naeim Henein ◽  
Sampad Mukhopadhyay ◽  
Peter Schihl
Keyword(s):  
Diesel Engine ◽  
Experimental Validation ◽  
Cetane Number ◽  
Negative Temperature ◽  
Single Cylinder ◽  
Combustion Behavior ◽  
Auto Ignition ◽  
Temperature Combustion ◽  
Ignition Quality ◽  
Ignition Quality Tester

Surrogates development is important to extensively investigate the combustion behavior of fuels. Development of comprehensive surrogates has been focusing on matching chemical and physical properties of their target fuel to mimic its atomization, evaporation, mixing, and auto-ignition behavior. More focus has been given to matching the derived cetane number (DCN) as a measure of the auto-ignition quality. In this investigation, we carried out experimental validation of a three-component surrogate for Sasol-Isoparaffinic Kerosene (IPK) in ignition quality tester (IQT) and in an actual diesel engine. The surrogate fuel is composed of three components (46% iso-cetane, 44% decalin, and 10% n-nonane on a volume basis). The IQT experiments were conducted as per ASTM D6890-10a. The engine experiments were conducted at 1500 rpm, two engine loads, and two injection timings. Analysis of ignition delay (ID), peak pressure, peak rate of heat release (RHR), and other combustion phasing parameters showed a closer match in the IQT than in the diesel engine. Comparison between the surrogate combustion behavior in the diesel engine and IQT revealed that matching the DCN of the surrogate to its respective target fuel did not result in the same negative temperature coefficient (NTC) profile—which led to unmatched combustion characteristics in the high temperature combustion (HTC) regimes, despite the same auto-ignition and low temperature combustion (LTC) profiles. Moreover, a comparison between the combustion behaviors of the two fuels in the IQT is not consistent with the comparison in the diesel engine, which suggests that the surrogate validation in a single-cylinder diesel engine should be part of the surrogate development methodology, particularly for low ignition quality fuels.

An Investigation on Sensitivity of Ignition Delay and Activation Energy in Diesel Combustion

2014 ◽  
Author(s):  
Umashankar Joshi ◽  
Ziliang Zheng ◽  
Amit Shrestha ◽  
Naeim Henein ◽  
Eric Sattler
Keyword(s):  
Activation Energy ◽  
Ignition Delay ◽  
Cetane Number ◽  
Ignition Process ◽  
Start Of Injection ◽  
Auto Ignition ◽  
Time Period ◽  
Ignition Quality ◽  
Ignition Quality Tester ◽  
Start Of Combustion

The auto-ignition process plays a major role in the combustion, performance, fuel economy and emission in diesel engines. The auto-ignition quality of different fuels has been rated by its cetane number (CN) determined in the CFR engine, according to ASTM D613. More recently, the Ignition Quality Tester (IQT), a constant volume vessel, has been used to determine the derived cetane number (DCN) to avoid the elaborate, time consuming and costly engine tests, according to ASTM D6890. The ignition delay period in these two standard tests and many investigations has been considered to be the time period between start of injection (SOI) and start of combustion (SOC). The ignition delay (ID) values determined in different investigations can vary due to differences in instrumentation and definitions. This paper examines the different definitions and the parameters that effect ID period. In addition the activation energy dependence on the ID definition is investigated. Furthermore, results of an experimental investigation in a single-cylinder research diesel engine will be presented while the charge density is kept constant during the ID period. The global activation energy is determined and its sensitivity to the charge temperature is examined.

Investigation of Physical and Chemical Delay Periods of Different Fuels in the Ignition Quality Tester

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Ziliang Zheng ◽  
Tamer Badawy ◽  
Naeim Henein ◽  
Eric Sattler
Keyword(s):  
Activation Energy ◽  
Cetane Number ◽  
Delay Period ◽  
Ignition Process ◽  
Ultra Low Sulfur Diesel ◽  
Air Temperatures ◽  
Auto Ignition ◽  
Ignition Quality ◽  
Ignition Quality Tester ◽  
Physical And Chemical

This paper investigates the physical and chemical ignition delay (ID) periods in the constant volume combustion chamber of the Ignition Quality Tester (IQT). IQT was used to determine the derived cetane number (DCN) according to ASTM D6890-10a standards. The fuels tested were ultra low sulfur diesel (ULSD), jet propellant-8 (JP-8), and two synthetic fuels of Sasol IPK and F-T SPK (S-8). A comparison was made between the DCN and cetane number (CN) determined according to ASTM-D613 standards. Tests were conducted under steady state conditions at a constant pressure of 21 bars and various air temperatures ranging from 778 K to 848 K. The rate of heat release (RHR) was calculated from the measured pressure trace, and a detailed analysis of the RHR trace was made particularly for the auto-ignition process. Tests were conducted to determine the physical and chemical delay periods by comparing results obtained from two tests. In the first test, the fuel was injected into air according to ASTM standards. In the second test, the fuel was injected into nitrogen. The point at which the two resultant pressure traces separated was considered to be the end of the physical delay period. The effects of the charge temperature on the total ID as defined in ASTM D6890-10a standards, as well as on the physical and chemical delays, were determined. It was noticed that the physical delay represented a significant part of the total ID over all the air temperatures covered in this investigation. Arrhenius plots were developed to determine the apparent activation energy for each fuel using different IDs. The first was based on the total ID measured according to ASTM standards. The second was the chemical delay determined in this investigation. The activation energy calculated from the total ID showed higher values for lower CN fuels except Sasol IPK. The activation energy calculated from the chemical delay period showed consistency in the increase of the activation energy with the drop in CN including Sasol IPK. The difference between the two findings could be explained by examining the sensitivity of the physical delay period of different fuels to the change in air temperature.

Effects of Injection Rate Profiles on Auto-Ignition in Ignition Quality Tester

2018 ◽  
Author(s):  
Yueqi Luo ◽  
Mohammed Jaasim Mubarak Ali ◽  
Zhen Huang ◽  
Hong Im
Keyword(s):  
Injection Rate ◽  
Auto Ignition ◽  
Ignition Quality ◽  
Ignition Quality Tester

Diesel Fuel Ignition Quality as Determined in the Ignition Quality Tester (IQT) - Part II

1997 ◽  
Author(s):  
Luc N. Allard ◽  
Norman J. Hole ◽  
Gary D. Webster ◽  
Thomas W. Ryan ◽  
Dale Ott ◽  
...  
Keyword(s):  
Diesel Fuel ◽  
Ignition Quality ◽  
Ignition Quality Tester

scholarly journals Rational Design and Testing of Anti-Knock Additives

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4923
Author(s):  
Andrew D. Ure ◽  
Manik K. Ghosh ◽  
Maria Rappo ◽  
Roland Dauphin ◽  
Stephen Dooley
Keyword(s):  
Rational Design ◽  
Reaction Pathway ◽  
Cetane Number ◽  
Research Octane Number ◽  
Ignition Quality ◽  
Ignition Quality Tester ◽  
Generic Design ◽  
The Relationship ◽  
Design And Testing

An innovative and informed methodology for the rational design and testing of anti-knock additives is reported. Interaction of the additives with OH● and HO2● is identified as the key reaction pathway by which non-metallic anti-knock additives are proposed to operate. Based on this mechanism, a set of generic design criteria for anti-knock additives is outlined. It is suggested that these additives should contain a weak X-H bond and form stable radical species after hydrogen atom abstraction. A set of molecular structural, thermodynamic, and kinetic quantities that pertain to the propensity of the additive to inhibit knock by this mechanism are identified and determined for a set of 12 phenolic model compounds. The series of structural analogues was carefully selected such that the physical thermodynamic and kinetic quantities could be systematically varied. The efficacy of these molecules as anti-knock additives was demonstrated through the determination of the research octane number (RON) and the derived cetane number(DCN), measured using an ignition quality tester (IQT), of a RON 95 gasoline treated with 1 mole % of the additive. The use of the IQT allows the anti-knock properties of potential additives to be studied on one tenth of the scale, compared to the analogous RON measurement. Using multiple linear regression, the relationship between DCN/RON and the theoretically determined quantities is studied. The overall methodology reported is proposed as an informed alternative to the non-directed experimental screening approach typically adopted in the development of fuel additives.

A Proposed Biodiesel Combustion Kinetics Based on the Computational Fluid Dynamics Results in an Ignition Quality Tester

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Mahmoud Elhalwagy ◽  
Chao Zhang
Keyword(s):  
Methyl Ester ◽  
Ignition Delay ◽  
Methyl Esters ◽  
Direct Injection ◽  
Combustion Process ◽  
Major Fatty Acid ◽  
Combustion Behavior ◽  
Ignition Quality ◽  
Reaction Constants ◽  
Ignition Quality Tester

In this paper, five biodiesel global combustion decomposition steps are added to a surrogate mechanism to accurately represent the chemical kinetics of the decomposition of different levels of saturation of biodiesel, which are represented by five major fatty acid methyl esters. The reaction constants were tuned based on the results from the numerical simulations of the combustion process in an ignition quality tester (IQT) in order to obtain accurate cetane numbers. The prediction of the complete thermophysical properties of the five constituents is also carried out to accurately represent the physics of the spray and vaporization processes. The results indicated that the combustion behavior is controlled more by the spray and breakup processes for saturated biodiesel constituents than by the chemical delay, which is similar to the diesel fuel combustion behavior. The chemical delay and low temperature reactions were observed to have greater effects on the combustion and ignition delay for the cases of the unsaturated biodiesels. The comparison between the physical ignition delay and overall ignition delay between the saturated and unsaturated biodiesel constituents has also confirmed those stronger effects for the physical delay in the saturated compounds as compared to the unsaturated compounds. The validation of the proposed model is conducted for the simulations of two direct injection diesel engines using palm methyl ester and rape methyl ester.

Effect of Cetane Improver on Combustion and Emission Characteristics of Coal-Derived Sasol Isomerized Paraffinic Kerosene in a Single Cylinder Diesel Engine

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Ziliang Zheng ◽  
Umashankar Joshi ◽  
Naeim Henein ◽  
Eric Sattler
Keyword(s):  
Diesel Engine ◽  
Cetane Number ◽  
Control Unit ◽  
Injection System ◽  
Oxides Of Nitrogen ◽  
Single Cylinder ◽  
Common Rail Injection System ◽  
Air Temperatures ◽  
Auto Ignition ◽  
Ignition Quality

Sasol isomerized paraffinic kerosene (IPK) is a coal-derived synthetic fuel under consideration as a blending stock with JP-8 for use in military ground vehicles. Since Sasol IPK is a low ignition quality fuel with derived cetane number (DCN) of 31, there is a need to improve its ignition quality. This paper investigates the effect of adding different amounts of Lubrizol 8090 cetane improver to Sasol IPK on increasing its DCN. The experimental investigation was conducted in a single cylinder research type diesel engine. The engine is equipped with a common rail injection system and an open engine control unit. Experiments covered different injection pressures and intake air temperatures. Analysis of test results was made to determine the effect of cetane improver percentage in the coal-derived Sasol IPK blend on auto-ignition, combustion and emissions of carbon monoxide (CO), total unburned hydrocarbon (HC), oxides of nitrogen (NOx), and particulate matter (PM). In addition, the effect of cetane improver on the apparent activation energy of the global auto-ignition reactions was determined.

Development of JP-8 Surrogates and their Validation using Ignition Quality Tester

2014 ◽  
Vol 7 (1) ◽  
pp. 337-351 ◽  
Author(s):  
Amit Shrestha ◽  
Ziliang Zheng ◽  
Tamer Badawy ◽  
Naeim Henein ◽  
Peter Schihl
Keyword(s):  
Ignition Quality ◽  
Ignition Quality Tester
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