Formation and control of aldehydes in alcohol fueled engines
01 Oct 1981-
TL;DR: In this article, several chemical kinetic models on the mechanism leading to aldehyde formation and emissions from alcohol fueled engines were examined to explore the appropriate control methods to reduce exhaust deodorization.
Abstract: Aldehyde formation and emissions from alcohol fueled engines are presented in this paper Several chemical kinetic models on the mechanism leading to aldehyde formation have been examined to explore the appropriate control methods to reduce exhaust aldehyde emissions Control of aldehydes in exhaust emissions by suitable alteration of engine operating parameters, by in cylinder treatment with additives like aniline and water, by external treatment like airpreheating, secondary air injection cooling water rate and exhaust treatment are examined The concept of surface ignition for alcohol fuels is briefly presented as a long range objective for using alcohols with minimal aldehyde emissions
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01 Jan 2015
TL;DR: In this paper, the laminar flame speeds of C 3 oxygenated fuels ( n -propanol, propanal and acetone) and hydrocarbon (propane) were measured in a combustion bomb to compare combustion characteristics of C3 alcohol, aldehyde, ketone, and alkane.
Abstract: The laminar flame speeds of C 3 oxygenated fuels ( n -propanol, propanal and acetone) and hydrocarbon (propane) were measured in a combustion bomb to compare combustion characteristics of C 3 alcohol, aldehyde, ketone, and alkane Propanal shows the highest flame speeds while acetone gives the lowest one The experimental observations are further interpreted with chemical kinetic models The effects of distinctive molecular structures on the fuel consumption pathways are clarified Propanal generates a large H atom pool that enhances the oxidation, leading to the highest flame speeds However, acetone forms methyl radical (CH 3 ) and has lower flame speeds as a consequence The calculated maximum concentrations of H, OH, and CH 3 confirm this analysis It is found that propanal yields the highest H and OH concentrations while acetone produces the lowest H and OH concentrations among all tested fuels Moreover, acetone presents higher CH 3 concentration, especially for fuel rich condition n -Propanol and propane show comparable flame speeds and similar radical concentrations, especially H and OH The different kinetics among hydrocarbon species with the same carbon numbers can provide a horizontal view in the hierarchical hydrocarbon chemistry
74 citations
Cites background from "Formation and control of aldehydes ..."
...Many studies have been focused on the detection and formation of these toxic emissions [12–14]....
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TL;DR: In this article, the authors presented the exhaust emission levels from a flexible fuel engine with heated intake air and fuel during cold start operation, following the US FTP-75 test schedule.
55 citations
TL;DR: In this paper, the authors describe the improvements on exhaust emissions and cold start obtained through utilization of a new type of cold-start auxiliary system for ethanol-fueled engines, which allowed for faster and uniform cold start, in comparison to the conventional system.
Abstract: This work describes the improvements on exhaust emissions and cold start obtained through utilization of a new type of cold-start auxiliary system for ethanol-fueled engines. Lower amounts of the gasoline used to help cold start and of ethanol injected during cold start and warm-up were used via introduction of a fuel injector in the new cold-start auxiliary system. The redesigned system allowed for faster and uniform cold start, in comparison to the conventional system, of around 31.1%. Reductions of raw hydrocarbon and carbon monoxide emissions in the cold stage of the FTP-75-based emissions test cycle were about 8.6 and 17.2%, respectively, while oxides of nitrogen and aldehyde emissions remained unchanged.
12 citations
Cites methods from "Formation and control of aldehydes ..."
...Ayyasamy et al. (1981) studied the effects of fuel-air mixture equivalence ratio on aldehyde emissions, using gasoline and methanol as fuels....
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TL;DR: In this paper, an ethanol-fueled vehicle was tested in a chassis dynamometer, following a standard urban cycle test procedure, and the results pointed to a reduction on aldehyde emissions for lower gear-change speeds and for richer fuel mixtures.
Abstract: This work presents results and analysis of experiments on aldehyde and the regulated pollutants CO, HC, and NOA emissions, with varying engine-running parameters. An ethanol-fueled vehicle was tested in a chassis dynamometer, following a standard urban cycle test procedure. The test simulated a medium-distance trip in an urban area, of approximately 5.8 km, with a warmed-up engine. The running parameters tested in the experiments were mixture equivalence ratio, the additional air flow used in decelerations (dash pot), the fuel interruption function in decelerations (cutoff), and gear-change speed. The results pointed to a reduction on aldehyde emissions for lower gear-change speeds and for richer fuel mixtures.
10 citations
Cites background from "Formation and control of aldehydes ..."
...Ayyasamy et al. (1981) observed that the high combustion temperature at near stoichiometric conditions produces a low amount of aldehydes....
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01 Feb 2003
TL;DR: In this article, a van supplied by Valley Transit of Lewiston, Idaho has been converted to catalytic ignition, in order to make the vehicle operate on either gasoline or Aquanol, modifications to the fuel handling, engine management, and ignition system were necessary.
Abstract: Aqueous fueled engines have the potential for lower emissions and higher engine efficiency than engines fueled with gasoline or diesel fuels. Past attempts to burn aqueous fuels in over-the-road vehicles have been unsuccessful due to difficulties in initiating combustion under varying environmental conditions. Ethanol-water mixtures, called Aquanol, require no special emulsifications to create and should provide significant emission reductions in CO and NOx, while producing no net CO2 emissions. Aldehydes, a part of the hydrocarbon emissions, are expected to increase with alcohol-based fuels. Understanding what parameters affect aldehyde formation will help create reduction strategies. Detailed detection of exhaust emissions is necessary for a quantitative comparison. Redundant measurements with two special purpose detectors will be used for emission comparisons. A van supplied by Valley Transit of Lewiston, Idaho has been converted to catalytic ignition. In order to make the vehicle operate on either gasoline or Aquanol, modifications to the fuel handling, engine management, and ignition system were necessary. A three-part vehicle test plan is currently underway to compare performance, fuel economy, and emissions between Aquanol and gasoline fuels.
1 citations
References
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01 Feb 1981
141 citations
Book•
01 Jun 1972
TL;DR: In this article, a standard text for the automotive industry explains in detail the fundamentals of emission formation and control for gasoline and diesel engines, which can be applied to other combustion systems, such as gas turbines and stationary power plants.
Abstract: This standard text for the automotive industry explains in detail the fundamentals of emission formation and control for gasoline and diesel engines. These concepts can be applied to other combustion systems, such as gas turbines and stationary power plants. Topics of discussion include: combustion in homogeneous mixtures; effect of design and operating variables on gasoline engine exhaust emissions; hydrocarbon evaporation emissions; diesel engine combustion emissions and controls; emission instrumentation; and automotive exhaust emission testing. 200 references, 197 figures.
121 citations
01 Feb 1976
TL;DR: In this paper, a single-cylinder engine with methanol fuel was compared to those obtained either with gasoline or a methanoline-water blend, and the results indicated that the advantages of blending water with methenol are outweighed by the disadvantages.
Abstract: Exhaust emission and performance characteristics of a single-cylinder engine fueled with methanol are compared to those obtained either with gasoline or a methanol-water blend. Our measurements of engine efficiency and power, and CO and NO/sub x/ emissions agree with trends established in the literature. Consequently, the emphasis is placed on organic emissions (unburned fuel including hydrocarbons, and aldehydes), an area in which there is no consensus in the literature. In all cases with methanol fueling, the unburned fuel (UBF) emissions were virtually all methanol as opposed to hydrocarbon compounds. Without special measures to overcome methanol's large heat of vaporization, UBF emissions were four times greater with methanol than those with gasoline. Similarly, aldehyde emissions were an order of magnitude greater with methanol. These high levels of organic emissions with methanol were related to inadequate fuel-air mixture preparation, which was caused by methanol's large heat of vaporization. Modifying the single-cylinder engine intake system to improve vaporization reduced UBF emissions 80 to 90% with methanol and 30 to 50% with gasoline. Aldehyde emissions were also significantly reduced by improving mixture preparation, but remained three to four times greater for methanol than for gasoline. Blending 10% water with methanol resulted in: (1) reducedmore » engine efficiency and power, (2) increased UBF emissions, (3) no measurable effect on aldehyde and CO emissions, and (4) reduced NO/sub x/ emissions. Our tests indicate that the advantages of blending water with methanol are outweighed by the disadvantages.« less
38 citations
01 Feb 1977
TL;DR: In this paper, a methanol-fueled single-cylinder engine was run at compression ratio (CR) from 8 to 18, and engine speed and airflow were constant at 1200 rpm and about half throttle, respectively; equivalence ratio (phi) was varied from 0.7 to 1.1; and spark timing from best power (MBT) to 10/sup 0/ retarded.
Abstract: One of the reasons methanol is considered an attractive alternative fuel for automobiles is its high octane quality, which may allow the use of high compression ratio (CR) engines. To evaluate compromises between engine efficiency and exhaust emissions, a methanol-fueled single-cylinder engine was run at CR's from 8 to 18. At each CR, engine speed and airflow were constant at 1200 rpm and about half throttle, respectively; equivalence ratio (phi) was varied from 0.7 to 1.1; and spark timing was varied from best power (MBT) to 10/sup 0/ retarded. Knock was observed only at CR = 18 with MBT spark timing. Increasing CR from 8 to 18 while maintaining MBT spark timing increased efficiency about 16%, but also increased NO/sub x/ and unburned fuel (UBF) emissions. Some previous studies have reported decreased NO/sub x/ emissions with increased CR, possibly because MBT spark timing was not maintained. Results of this study indicate that constant NO/sub x/ emissions can be maintained by retarding spark timing while increasing CR to improve efficiency. Retarding spark timing, however, only marginally reduced UBF emissions. Vehicle tests are necessary to define the optimum CR for methanol fueling because exhaust emission trends and knocking tendency may be differentmore » than those observed with this single-cylinder engine.« less
35 citations