Effects of Fuel Injection and Intake Airflow on Direct-injection Spark-ignition Combustion PDF Download

Author: Won-Seok Chang
Publisher:
ISBN:
Category :
Languages : en
Pages : 186

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Author: Addison May Rothrock
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 24

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Author: Mark Casarella
Publisher:
ISBN:
Category :
Languages : en
Pages : 300

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Author: F. Zhao
Publisher: Elsevier
ISBN: 008055279X
Category : Technology & Engineering
Languages : en
Pages : 129

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The process of fuel injection, spray atomization and vaporization, charge cooling, mixture preparation and the control of in-cylinder air motion are all being actively researched and this work is reviewed in detail and analyzed. The new technologies such as high-pressure, common-rail, gasoline injection systems and swirl-atomizing gasoline fuel injections are discussed in detail, as these technologies, along with computer control capabilities, have enabled the current new examination of an old objective; the direct-injection, stratified-charge (DISC), gasoline engine. The prior work on DISC engines that is relevant to current GDI engine development is also reviewed and discussed. The fuel economy and emission data for actual engine configurations have been obtained and assembled for all of the available GDI literature, and are reviewed and discussed in detail. The types of GDI engines are arranged in four classifications of decreasing complexity, and the advantages and disadvantages of each class are noted and explained. Emphasis is placed upon consensus trends and conclusions that are evident when taken as a whole; thus the GDI researcher is informed regarding the degree to which engine volumetric efficiency and compression ratio can be increased under optimized conditions, and as to the extent to which unburned hydrocarbon (UBHC), NOx and particulate emissions can be minimized for specific combustion strategies. The critical area of GDI fuel injector deposits and the associated effect on spray geometry and engine performance degradation are reviewed, and important system guidelines for minimizing deposition rates and deposit effects are presented. The capabilities and limitations of emission control techniques and after treatment hardware are reviewed in depth, and a compilation and discussion of areas of consensus on attaining European, Japanese and North American emission standards presented. All known research, prototype and production GDI engines worldwide are reviewed as to performance, emissions and fuel economy advantages, and for areas requiring further development. The engine schematics, control diagrams and specifications are compiled, and the emission control strategies are illustrated and discussed. The influence of lean-NOx catalysts on the development of late-injection, stratified-charge GDI engines is reviewed, and the relative merits of lean-burn, homogeneous, direct-injection engines as an option requiring less control complexity are analyzed.

Author: Philip William Stephenson
Publisher:
ISBN:
Category :
Languages : en
Pages : 448

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Author: National Research Council
Publisher: National Academies Press
ISBN: 0309216389
Category : Science
Languages : en
Pages : 373

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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.

Author:
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ISBN:
Category :
Languages : en
Pages :

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Abstract : The characteristics of gasoline sprayed directly into combustion chambers are of critical importance to engine out emissions and combustion system development. The optimization of the spray characteristics to match the in-cylinder flow field, chamber geometry, and spark location are vital tasks during the development of an engine combustion strategy. Furthermore, the presence of liquid fuel during combustion in Spark-Ignition (SI) engines causes increased hydrocarbon (HC) emissions [1]. Euro 6, LEVIII, and US Tier 3 emissions regulations reduce the allowable particulate mass significantly from the previous standards. LEVIII standards reduce the acceptable particulate emission to 1 mg/mile [2]. A good Direct Injection Spark Ignited (DISI) strategy vaporizes the correct amount of fuel at the proper point in the engine cycle with the proper in-cylinder air flow for optimal power output with minimal emissions. The opening and closing phases of DISI injectors is crucial to this task as the spray produces larger droplets during both theses phases. This work focuses on the results from a novel method to investigate fuel behavior upon closing of the fuel injector. A Design of Experiments (DOE) was used to determine the effect of pressure, temperature, and pulse-width of the fuel spray after the closing event. Experiments determined that the primary source of controlling the droplet size and the mass post injector closing for a given injector was the temperature. It was found that the end of injection behavior is a highly dynamic, complex event including, but not limited to, effects from the injector design, deposit concentration, and fuel type.

Author: Christopher William Nilsen
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Ducted fuel injection (DFI) has been proposed as a strategy to enhance the fuel/charge-gas mixing within the combustion chamber of a direct-injection mixing-controlled compression-ignition engine. The concept involves injecting each fuel spray through a small tube within the combustion chamber to facilitate the creation of a leaner mixture in the autoignition zone, relative to a conventional free-spray configuration (i.e., a fuel spray that is not surrounded by a duct). This dissertation investigates the effects of ducted fuel injection on engine-out emissions and efficiency with two-orifice and four-orifice injector tips across a wide range of conditions. A numerical study contributes to the understanding of the fluid flow effects of DFI. The experiments in chapter two use a two-orifice fuel injector to test two duct configurations relative to conventional diesel combustion. The result is that DFI is confirmed to be effective at curtailing engine-out soot emissions. It also breaks the tradeoff between emissions of soot and nitrogen oxides (NO[subscript x]) by simultaneously attenuating soot and NO[subscript x] with increasing dilution. The third chapter expands on the second by comparing ducted fuel injection to conventional diesel combustion over a wide range of operating conditions and at higher loads (up to 8.7 bar gross indicated mean effective pressure) with a four-orifice fuel injector. This chapter is achieved through sweeps of intake-oxygen mole-fraction, injection duration, intake pressure, start of combustion timing, fuel-injection pressure, and intake temperature. Ducted fuel injection is shown to curtail engine-out soot emissions at all tested conditions. Under certain conditions, ducted fuel injection can attenuate engine-out soot by over a factor of 100. In addition to producing significantly lower engine-out soot emissions, ducted fuel injection enables the engine to be operated at low-NO[subscript x] conditions that are not feasible with conventional diesel combustion due to high soot emissions. The fourth chapter explores 1.1 bar IMEP[subscript g] (low load) conditions and 10 bar IMEP[subscript g] (higher-load) conditions with the same four-orifice fuel injector as in chapter three. DFI and CDC are directly compared at each operating point in the study. At the idle condition, the intake dilution was swept to elucidate the soot and NO[subscript x] performance of DFI in this new load range. This expands the range of conditions over which DFI has been shown to attenuate soot formation. It also shows that DFI enables low-NO[subscript x], low-load operation that is not achievable with CDC due to excessive soot formation at high dilution levels. The fifth chapter uses a numerical model to develop the understanding of the fluid flow effects of DFI. This enabled studies of entrainment and mixing that would have been much more challenging to do in an experiment. This showed that DFI enhances charge gas entrainment before the duct and blocks entrainment inside of the duct. Mixing is enhanced by the duct, which resulted in lower peak equivalence ratios at the end of the duct.

Author:
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ISBN:
Category :
Languages : en
Pages :

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Abstract : A production Kohler 8.5RES residential stand-by generator set (Genset) was selected as the platform for this study due to its availability, simplicity, and price point. The Genset consists of a spark ignited (SI) two cylinder vee style internal combustion engine (ICE) capable of running natural gas or propane fuel with a 8.5 kW generator connected directly to the engines crankshaft. This allows for electrical load to be applied to the generator which in turn loads the engine without the use of a conventional dynamometer. A water cooled fully adjustable electric resistive load bank allows for easy adjustment to the desired load point. The electrical power generated was measured to determine the ICE output power and calculate the fuel energy to electrical energy conversion efficiency. To allow for control of the engine while testing it was modified from its original carbureted form to a port fuel injected (PFI) configuration and the original fixed spark timing system was removed and replaced with a coil ignition system. An electronic throttle body (ETB) was fitted to allow adjustment to the incoming air flow. The cylinder heads were modified to allow for a production direct inject (DI) fuel injector which used to deliver water to the combustion chamber and an in cylinder pressure transducer for analysis of various combustion parameters. The genset and test cell were instrumented with low speed and high speed dataacquisition (DAQ) systems to monitor and capture data at the chosen operatingconditions. The high speed data captured by the DAQ was used in conjunction with anear real-time combustion analysis program which calculated and logged combustionparameters and allowed for optimization of spark timing at each test point. Low speed data including fuel consumption, air mass flow rat, water consumption, and electrical power generated along with other engine parameters were monitored and logged as well. The ICE was tested at three different compression ratios (CRs) by changing the pistons and then by removing material from the cylinder head to decrease the clearance volume. The CR that came from the engine supplier was the first to be tested, second a CR in the range of 10:1-11:1 was targeted, and the range of the third CR was 14:1-15:1. The exact values of the CRs tested were calculated once the modifications were complete and volume measurements could be made. The first CR tested was 8.5:1 which is what the engine comes with from the supplier, the second 10.75:1 after changing pistons, and the third 14.3:1 after removing material from the cylinder head. Baseline data was collected at the 8.5:1 CR using the factory the fuel and ignition system to be used for comparison. Once the fuel, spark, and ETB modifications were complete tests were conducted by varying the load from 0 kW to the maximum attainable load at each test condition in 1 kW increments while targeting a relative air-fuel ratio (lambda, λ) of 1.0 and a speed of 3600 rpm. Using the combustion analysis software the gross indicated mean effective pressure (IMEP) was maximized for each test by varying spark timing. Water was injected into the combustion chamber at water to fuel ratios (WFRs) of 0.38, 1.0, and 1.5 by mass. These WFRs were chosen by the sponsor; the lowest possible WFR was to be tested as well as the 1.0 and 1.5 ratios. The lowest value of 0.38 was determined by testing the mass flow rate of the water injectors at decreasing durations. It was found that at WFRs lower than 0.38 the mass of water injected varied due to the injector's response properties. The start of injection (SOI) for water was swept from 180 degrees before top dead center (℗ʻBTDC) to 40 ℗ʻBTDC on the compression stroke in 20℗ʻ increments at each load condition tested. Before water injection tests began, each load point was tested and optimized to obtain baselines to be used for comparison against the water injection results for each CR tested. For each test performed an analysis was conducted to determine the effects of water injection of net fuel conversion efficiency, coefficient of variation (COV) of IMEP, and heat release rate which are discussed in greater detail later in this paper. Fuel conversion efficiency was used to determine if the water increased or decreased the conversion from fuel energy to mechanical work and quantified how it was impacted. The stability of combustion was determined by using the IMEP coefficient of variance which is common practice in ICE analysis to see how the water effected the variance in IMEP from cycle to cycle. Lastly heat release data was used to determine if the burn rate and ignition delay was impacted with the presence of water. From this data trends were identified and conclusions drawn regarding the overall impact water injection has on combustion.

Author: Hua Zhao
Publisher: CRC Press
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 562

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Homogeneous charge compression ignition (HCCI)/controlled auto-ignition (CAI) has emerged as one of the most promising engine technologies with the potential to combine fuel efficiency and improved emissions performance, offering reduced nitrous oxides and particulate matter alongside efficiency comparable with modern diesel engines. Despite the considerable advantages, its operational range is rather limited and controlling the combustion (timing of ignition and rate of energy release) is still an area of on-going research. Commercial applications are, however, close to reality. HCCI a.