The Ignition of Fuels by Rapid Compression

The Ignition of Fuels by Rapid Compression PDF Author:
Publisher:
ISBN:
Category : Combustion
Languages : en
Pages : 72

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The Ignition of Fuels by Rapid Compression

The Ignition of Fuels by Rapid Compression PDF Author:
Publisher:
ISBN:
Category : Combustion
Languages : en
Pages : 72

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Book Description


Ignition Study in Rapid Compression Machine

Ignition Study in Rapid Compression Machine PDF Author: Tairin Hahn
Publisher:
ISBN:
Category :
Languages : en
Pages : 162

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Book Description
As it becomes more and more difficult to find "easy" oil, various alternative fuels are introduced to the markets. These fuels have chemical properties that are different from the traditional gasoline and diesel fuels so that engine efficiency and other engine behaviors may be affected To improve engine efficiency and to identify which alternative fuel is the cleanest fuel solution, it is necessary to compile information about the ignition delay, which governs auto-ignition in spark-ignition (SI), compression-ignition (CI) and homogeneous charge compression-ignition (HCCI) engines. In this study, we measured ignition delay on the Rapid Compression Machine (RCM). RCM is a single-stroke device, which compresses uniform mixtures to engine-like condition. We can interpret from the pressure the detailed heat release process. A comprehensive ignition delay database of toluene/n-heptane mixtures and gasoline/ethanol mixtures was established The data allow us to calculate the auto-ignition behavior in engines. Depending on application the correct choice of alternative fuels may be made.

Fuel Ignition in a Rapid Compression Machine

Fuel Ignition in a Rapid Compression Machine PDF Author: W. W. Haskell
Publisher:
ISBN:
Category : Combustion
Languages : en
Pages : 5

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Rapid Compression Machine Measurements of Ignition Delays for Primary Reference Fuels

Rapid Compression Machine Measurements of Ignition Delays for Primary Reference Fuels PDF Author: Pyongwan Park
Publisher:
ISBN:
Category : Automobiles
Languages : en
Pages : 276

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A Rapid Compression Machine Suitable for Studying Short Ignition Delays

A Rapid Compression Machine Suitable for Studying Short Ignition Delays PDF Author: W. A. Leary
Publisher:
ISBN:
Category : Fuel
Languages : en
Pages : 43

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Book Description
The apparatus opens new possibilities for studying the detonation characteristics of fuels. Also, the tests can be conducted on a few millimeters of fuel.

Kinetic Modeling of Hydrocarbon Autoignition at Low and Intermediate Temperatures in a Rapid Compression Machine

Kinetic Modeling of Hydrocarbon Autoignition at Low and Intermediate Temperatures in a Rapid Compression Machine PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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A computer model is used to examine oxidation of hydrocarbon fuels in a rapid compression machine. For one of the fuels studied, n-heptane, significant fuel consumption is computed to take place during the compression stroke under some operating conditions, while for the less reactive n-pentane, no appreciable fuel consumption occurs until after the end of compression. The third fuel studied, a 60 PRF mixture of iso-octane and n-heptane, exhibits behavior that is intermediate between that of n-heptane and n-pentane. The model results indicate that computational studies of rapid compression machine ignition must consider fuel reaction during compression in order to achieve satisfactory agreement between computed and experimental results.

Experiments on the Effects of Dilution and Fuel Composition on Ignition of Gasoline and Alternative Fuels in a Rapid Compression Machine

Experiments on the Effects of Dilution and Fuel Composition on Ignition of Gasoline and Alternative Fuels in a Rapid Compression Machine PDF Author: Prasanna Chinnathambi
Publisher:
ISBN: 9781687981233
Category : Electronic dissertations
Languages : en
Pages : 262

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In the first part of this work, ignition of methane-air mixtures under excess air dilution is studied. When excess air is used in SI engine operation, thermal efficiency is increased due to increase in compression ratio together with reduced pumping and heat loses. However, stable operation with excess air is challenging due to poor flammability of the resulting diluted mixture. Hence in order to achieve stable and complete combustion a turbulent jet ignition (TJI) system is used to improve combustion of lean methane-air mixtures. Various nozzle designs and operating strategies for a TJI system were tested in a rapid compression machine. 10-90% burn duration measurements were useful in assessing the performance of the nozzle designs while the 0-10% burn durations indicated if optimal air-fuel ratio is achieved within the pre-chamber at the time of ignition. The results indicated that distributed-jets TJI system offered faster and stable combustion while the concentrated-jets TJI system offered better dilution tolerance.Knock in a SI engine occurs due to autoignition of the end gas mixture and typically occurs in the negative temperature coefficient (NTC) region of the fuel-air mixture. Dilution of intake charge with cold exhaust recirculation gases (EGR) reduces combustion temperatures and decreases mixture reactivity thereby reducing knocking tendency. This enables optimal spark timings to be used, thereby increasing efficiency of SI engines which would otherwise be knock limited. Effect of cold EGR dilution is studied in the RCM by measuring the autoignition delay times of gasoline and gasoline surrogate mixtures diluted with varying levels of CO2. The autoignition experiments in the RCM were performed using a novel direct test chamber (DTC) charge preparation approach. The DTC approach enabled mixture preparation directly within the combustion chamber and eliminated the need for mixing tanks. Effect of CO2 dilution in retarding the autoignition delay times was more pronounced in the NTC region, while it was weaker in the low temperature and high temperature regions. The retarding effect was found to be dependent on both the octane number and the fuel composition of the gasoline being studied.Finally, the effect of substituting ethanol(biofuel) in gasoline surrogates for up to 40% by volume is studied. Ethanol is an octane booster, but it blends antagonistically with aromatics such as toluene and synergistically with alkanes with respect to the resulting octane number of the blends. In order to study this blending effect, two gasoline surrogates containing only alkanes (PRF), and alkanes with large amounts of toluene (TRF) are blended with varying levels of ethanol. The ignition delay times of the resulting mixtures are measured in a rapid compression machine and kinetic analysis was carried out using numerical simulations. The kinetic analysis revealed that ethanol controlled the final stages of ignition for the PRF blends when more than 10% by volume of ethanol is present. However, in the TRF blends, toluene controlled the ignition until mole fractions of ethanol became higher than the toluene indicating the reason for the antagonistic blending nature. It was found that the RON values of the resulting blends matched the trend of the ignition delay times recorded at 740K and 21 bar compressed conditions. This enables qualitative assessment of the RON numbers for new biofuel blends by measuring their ignition delay times in the RCM.

Assessment of Fuel Economy Technologies for Light-Duty Vehicles

Assessment of Fuel Economy Technologies for Light-Duty Vehicles PDF Author: National Research Council
Publisher: National Academies Press
ISBN: 0309216389
Category : Science
Languages : en
Pages : 373

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Book Description
Various combinations of commercially available technologies could greatly reduce fuel consumption in passenger cars, sport-utility vehicles, minivans, and other light-duty vehicles without compromising vehicle performance or safety. Assessment of Technologies for Improving Light Duty Vehicle Fuel Economy estimates the potential fuel savings and costs to consumers of available technology combinations for three types of engines: spark-ignition gasoline, compression-ignition diesel, and hybrid. According to its estimates, adopting the full combination of improved technologies in medium and large cars and pickup trucks with spark-ignition engines could reduce fuel consumption by 29 percent at an additional cost of $2,200 to the consumer. Replacing spark-ignition engines with diesel engines and components would yield fuel savings of about 37 percent at an added cost of approximately $5,900 per vehicle, and replacing spark-ignition engines with hybrid engines and components would reduce fuel consumption by 43 percent at an increase of $6,000 per vehicle. The book focuses on fuel consumption-the amount of fuel consumed in a given driving distance-because energy savings are directly related to the amount of fuel used. In contrast, fuel economy measures how far a vehicle will travel with a gallon of fuel. Because fuel consumption data indicate money saved on fuel purchases and reductions in carbon dioxide emissions, the book finds that vehicle stickers should provide consumers with fuel consumption data in addition to fuel economy information.

Gasoline Surrogate Modeling of Gasoline Ignition in a Rapid Compression Machine and Comparison to Experiments

Gasoline Surrogate Modeling of Gasoline Ignition in a Rapid Compression Machine and Comparison to Experiments PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 14

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The use of gasoline in homogeneous charge compression ignition engines (HCCI) and in duel fuel diesel - gasoline engines, has increased the need to understand its compression ignition processes under engine-like conditions. These processes need to be studied under well-controlled conditions in order to quantify low temperature heat release and to provide fundamental validation data for chemical kinetic models. With this in mind, an experimental campaign has been undertaken in a rapid compression machine (RCM) to measure the ignition of gasoline mixtures over a wide range of compression temperatures and for different compression pressures. By measuring the pressure history during ignition, information on the first stage ignition (when observed) and second stage ignition are captured along with information on the phasing of the heat release. Heat release processes during ignition are important because gasoline is known to exhibit low temperature heat release, intermediate temperature heat release and high temperature heat release. In an HCCI engine, the occurrence of low-temperature and intermediate-temperature heat release can be exploited to obtain higher load operation and has become a topic of much interest for engine researchers. Consequently, it is important to understand these processes under well-controlled conditions. A four-component gasoline surrogate model (including n-heptane, iso-octane, toluene, and 2-pentene) has been developed to simulate real gasolines. An appropriate surrogate mixture of the four components has been developed to simulate the specific gasoline used in the RCM experiments. This chemical kinetic surrogate model was then used to simulate the RCM experimental results for real gasoline. The experimental and modeling results covered ultra-lean to stoichiometric mixtures, compressed temperatures of 640-950 K, and compression pressures of 20 and 40 bar. The agreement between the experiments and model is encouraging in terms of first-stage (when observed) and second-stage ignition delay times and of heat release rate. The experimental and computational results are used to gain insight into low and intermediate temperature processes during gasoline ignition.

Impact of Thermodynamic Properties and Heat Loss on Ignition of Transportation Fuels in Rapid Compression Machines

Impact of Thermodynamic Properties and Heat Loss on Ignition of Transportation Fuels in Rapid Compression Machines PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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