Hydrocarbon Emissions in a Homogeneous Direct-injection Spark Engine PDF Download
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Author: Ronald S. Tharp
Publisher:
ISBN:
Category :
Languages : en
Pages : 89
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Book Description
In order to better understand the effects on hydrocarbon emissions of loading, engine temperature, fuel type, and injection timing, a series of experiments was performed. The effect of loading was observed by running the engine at a higher temperature and more open throttle than would typically be observed at fast idle or low load driving. The effects of coolant temperature, the charge motion control valve, spark timing and rail pressure were tested through holding all other variables constant and sweeping through different injection timing to observe the effect on emissions and power output. A new fuel system was designed to allow for the quick testing of different ethanol blends. The system allowed for comparison testing of an 85% ethanol blend to UTG 91 as a function of coolant temperature and injection timing. Measurement of cylinder pressure and hydrocarbon emissions near the exhaust valve allowed for a better understanding of engine operation and the effect of using high ethanol content fuels. Initial testing was also done on 15% and 40% ethanol blends. The results revealed that engine emissions decrease as a function of reduced loading and higher engine temperatures. Sweeps of injection timings for all fuels demonstrated high hydrocarbon emissions for earlier injection timings which fell as injection timing was retarded. A secondary peak was observed in hydrocarbon emissions for an injection timing of approximately 150 CAD aTDC intake. Analysis of rate of fuel injection vs. indicated power revealed a steady decrease in indicated efficiency as injection timing was retarded up to 120 CAD aTDC Intake and then a slow rise in efficiency as the timing was further retarded. The exact causes of the decrease in engine efficiency are unknown; however, possible explanations involve increased heat transfer from the cylinder and piston, fuel loss, and inefficient combustion due to impingement on cold surfaces.
Author: Ronald S. Tharp
Publisher:
ISBN:
Category :
Languages : en
Pages : 89
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Book Description
In order to better understand the effects on hydrocarbon emissions of loading, engine temperature, fuel type, and injection timing, a series of experiments was performed. The effect of loading was observed by running the engine at a higher temperature and more open throttle than would typically be observed at fast idle or low load driving. The effects of coolant temperature, the charge motion control valve, spark timing and rail pressure were tested through holding all other variables constant and sweeping through different injection timing to observe the effect on emissions and power output. A new fuel system was designed to allow for the quick testing of different ethanol blends. The system allowed for comparison testing of an 85% ethanol blend to UTG 91 as a function of coolant temperature and injection timing. Measurement of cylinder pressure and hydrocarbon emissions near the exhaust valve allowed for a better understanding of engine operation and the effect of using high ethanol content fuels. Initial testing was also done on 15% and 40% ethanol blends. The results revealed that engine emissions decrease as a function of reduced loading and higher engine temperatures. Sweeps of injection timings for all fuels demonstrated high hydrocarbon emissions for earlier injection timings which fell as injection timing was retarded. A secondary peak was observed in hydrocarbon emissions for an injection timing of approximately 150 CAD aTDC intake. Analysis of rate of fuel injection vs. indicated power revealed a steady decrease in indicated efficiency as injection timing was retarded up to 120 CAD aTDC Intake and then a slow rise in efficiency as the timing was further retarded. The exact causes of the decrease in engine efficiency are unknown; however, possible explanations involve increased heat transfer from the cylinder and piston, fuel loss, and inefficient combustion due to impingement on cold surfaces.
Author: Michael S. Radovanovic
Publisher:
ISBN:
Category :
Languages : en
Pages : 88
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Book Description
For the purpose of researching hydrocarbon (HC) emissions in a direct-injection spark ignited (DISI) engine, five experiments were performed. These experiments clarified the role of coolant temperature, injection pressure, and injection timing in HC emissions; the final two experiments illustrated the effect of coolant temperature and injection pressure on separate sweeps of injection timing and the subsequent HC levels. The first three experiments were performed with isopentane. All five of the experiments were repeated with two fuels: UTG 91, a typical research gasoline, and a fuel with a high driveability index (DI), i.e. a less volatile fuel. The results showed less-than intuitive results for the response of HC to varying coolant temperature and varying injection pressure. For the coolant temperature data, the deviation from intuition is discussed and is probably due to vaporization problems. For the injection pressure results, the counterintuitive trend is expected to be the balance of two negative effects of high and low fuel pressure: high droplet velocities and large droplet diameters. Finally, the injection timing results were more logical. The early injections are high for this engine due to late exhaust valve closing, and the late injections have high HC because of a decreasing time to vaporize and poor mixing caused by the lack of intake air motion.
Author: F. Zhao
Publisher: Elsevier
ISBN: 008055279X
Category : Technology & Engineering
Languages : en
Pages : 129
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Book Description
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: Hakan Sandquist
Publisher:
ISBN:
Category :
Languages : en
Pages : 10
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 32
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Author: Fuquan Zhao
Publisher: SAE International
ISBN: 1468603388
Category : Technology & Engineering
Languages : en
Pages : 372
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Book Description
This book covers the latest global technical initiatives in the rapidly progressing area of gasoline direct injection (GDI), spark-ignited gasoline engines and examines the contribution of each process and sub-system to the efficiency of the overall system. Including discussions, data, and figures from many technical papers and proceedings that are not available in the English language, Automotive Gasoline Direct Injection Systems will prove to be an invaluable desk reference for any GDI subject or direct-injection subsystem that is being developed worldwide.
Author: Kevin David Cedrone
Publisher:
ISBN:
Category :
Languages : en
Pages : 191
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Book Description
Gasoline consumption and pollutant emissions from transportation are costly and have serious, demonstrated environmental and health impacts. Downsized, turbocharged direct-injection spark ignition (DISI) gasoline engines consume less fuel and achieve superior performance compared with conventional port fuel injected spark ignition (PFI-SI) engines. Although more efficient, turbocharged DISI engines have new emissions challenges during cold start. DISI fuel injection delivers more liquid fuel into the combustion chamber, increasing the emissions of unburned hydrocarbons. The turbocharger slows down activation (warm-up) of the catalytic exhaust after-treatment system. The objective of this research is to find a control strategy that: 1. Accelerates warm-up of the catalyst, and 2. Maintains low emissions of unburned hydrocarbons (UBHCs) during the catalyst warm-up process. This research includes a broad experimental survey of engine behaviour and emission response for a modern turbocharged DISI engine. The study focuses on the idle period during cold-start for which DISI engine emissions are worst. Engine experiments and simulations show that late and slow combustion lead to high exhaust gas temperatures and mass flow rate for fast warm-up. However, late and slow combustion increase the risk of partial-burn misfire. At the misfire limit for each parameter, the following conclusions are drawn: 1. Late ignition timing is the most effective way to increase exhaust enthalpy flow rate for fast catalyst warm-up. 2. By creating a favourable spatial fuel-air mixture stratification, split fuel injection can simultaneously retard and stabilize combustion to improve emissions and prevent partial-burn misfire. 3. Excessive trapped residuals from long valve overlap limit the potential for valve timing to reduce cold-start emissions. 4. Despite their more challenging evaporation characteristics, fuel blends with high ethanol content showed reasonable emissions behaviour and greater tolerance to late combustion than neat gasoline. 5. Higher exhaust back-pressure leads to high exhaust temperature during the exhaust stroke, leading to significantly more post-flame oxidation. 6. Post-flame oxidation in the combustion chamber and exhaust system play a critical role in decreasing the quantity of catalyst-in emissions due to hydrocarbons that escape primary (flame) combustion. A cold start strategy combining late ignition, 15% excess air, and high exhaust backpressure yielded the lowest cumulative hydrocarbon emissions during cold start.
Author: Anthony John Giovanetti
Publisher:
ISBN:
Category : Automobiles
Languages : en
Pages : 23
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Author: Phillip Price
Publisher:
ISBN:
Category :
Languages : en
Pages : 15
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Author: Won-Seok Chang
Publisher:
ISBN:
Category :
Languages : en
Pages : 186
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Book Description
