Effects of Emulsified Fuel on Combustion in a Four-Stroke Diesel Engine

1991 ◽  
Vol 35 (04) ◽  
pp. 356-363
Author(s):  
James A. Harbach ◽  
Vito Agosta

While the use of emulsified fuel in diesel engines has been an area of much research interest in recent years, the promising results reported in laboratories have not been easy to reproduce in commercial practice. Many of these studies have only measured external effects such as fuel consumption and exhaust emissions. A single-cylinder research engine was operated with water/diesel fuel oil and hydrous ethanol/diesel fuel oil emulsions of varying percentages. Crank angle, cylinder pressure and injector lift were recorded electronically over 50 engine cycles, permitting calculation of the mean and standard deviation of key combustion parameters. The results showed decreased fuel consumption and increased ignition delay, peak cylinder pressure and maximum cylinder pressure rise rate for emulsion operation. While the standard deviation data showed little change in cycle-to-cycle variation for wateremulsion operation, increases of over 200 percent were measured for operation at ethanol amounts over 20 percent.

Author(s):  
Ashwin Salvi ◽  
Reed Hanson ◽  
Rodrigo Zermeno ◽  
Gerhard Regner ◽  
Mark Sellnau ◽  
...  

Gasoline compression ignition (GCI) is a cost-effective approach to achieving diesel-like efficiencies with low emissions. Traditional challenges with GCI arise at low-load conditions due to low charge temperatures causing combustion instability and at high-load conditions due to peak cylinder pressure and noise limitations. The fundamental architecture of the two-stroke Achates Power Opposed-Piston Engine (OP Engine) enables GCI by decoupling piston motion from cylinder scavenging, allowing for flexible and independent control of cylinder residual fraction and temperature leading to improved low load combustion. In addition, the high peak cylinder pressure and noise challenges at high-load operation are mitigated by the lower BMEP operation and faster heat release for the same pressure rise rate of the OP Engine. These advantages further solidify the performance benefits of the OP Engine and demonstrate the near-term feasibility of advanced combustion technologies, enabled by the opposed-piston architecture. This paper presents initial results from a steady state testing on a brand new 2.7L OP GCI multi-cylinder engine. A part of the recipe for successful GCI operation calls for high compression ratio, leading to higher combustion stability at low-loads, higher efficiencies, and lower cycle HC+NOx emissions. In addition, initial results on catalyst light-off mode with GCI are also presented. The OP Engine’s architectural advantages enable faster and earlier catalyst light-off while producing low emissions, which further improves cycle emissions and fuel consumption over conventional engines.


2019 ◽  
Vol 969 ◽  
pp. 451-460
Author(s):  
Manpreet Singh ◽  
Mohd Yunus Sheikh ◽  
Dharmendra Singh ◽  
P. Nageswara Rao

The rapid rise in energy requirement and problem regarding atmosphere pollutions, renewable biofuels are the better alternative choice for the internal combustion engine to partially or totally replace the pollutant petroleum fuel. In the present work, thumba (Citrullus colocynthis) non-edible vegetable oil is used for the production of biodiesel and examine its possibility as diesel engine fuel. Transesterification process is used to produce biodiesel from thumba non-edible vegetable oil. Thumba biodiesel (TBD) is used to prepare five different volume concentration (blends) with neat diesel (D100), such as TBD5, TBD15, TBD25, TBD35 and TBD45 to run a single cylinder diesel engine. The diesel engine's combustion parameter such as in-cylinder pressure, rate of pressure rise, net heat release rate, cumulative heat release, mean gas temperature, and mass fraction burnt analyzed through graphs and compared all thumba biodiesel blends result with neat diesel fuel. The mass fraction burnt start earlier for thumba biodiesel blends compared to diesel fuel because of less ignition delay while peak in-cylinder pressure, maximum rate of pressure rise, maximum net heat release rate, maximum cumulative heat release, and maximum mean gas temperature has found decreased results up to 1.93%, 5.53%, 4.11%, 4.65%, and 1.73% respectively for thumba biodiesel.


Author(s):  
Qi Donghui ◽  
Zhou Longbao ◽  
Liu Shenghua

This paper studies the combustion characteristics and performances of a LPG/diesel blend-fuel engine; the influences of mixing ratio of LPG in diesel on the ignition timing, in-cylinder pressure, heat-release rate, specific fuel consumption, power output, and exhaust emissions have been identified. The results indicate that the ignition delay of blend fuel was obviously longer than that of diesel and the higher the mixing ratio of LPG in diesel, the longer the ignition delay. When the mixing ratio of LPG in diesel was 10 per cent, the peak in-cylinder gas pressure and the peak rate of pressure rise were slightly higher than those of diesel, and the corresponding crank angles at which the peak values occurred were almost the same as those of diesel. When the mixing ratio was 30 per cent, the peak in-cylinder pressure and the peak rate of pressure rise were lower than those of diesel, and the corresponding crank angles were retarded. With the increasing of mixing ratio of LPG in diesel, the peak rate of heat release increased and the corresponding crank angles were retarded. The equivalent specific fuel consumption of L10 was the same as that of diesel, but that of L30 was slight higher. The power output of the diesel engine was higher than those of L10 and L30 at speed characteristic of full load, especially at high engine speed. With the increasing of mixing ratio, the smoke emissions and NOx emissions were greatly reduced, and CO emissions decreased too, but HC emissions slightly increased.


2021 ◽  
Vol 3 (5) ◽  
Author(s):  
K. Venkatesan

Abstract This article examines the prospects of using toluene added cashew nut shell pyro oil–diesel blends as alternative fuels in CI engine. Effects of adding fixed proportion (by vol.) of toluene (TU) to various cashew nut shell pyro oil (CPO)–diesel (D) blends on the performance and exhaust emission characteristics of a direct injection, single cylinder, water cooled, naturally-aspirated, constant speed run, 4-stroke CI engine were investigated under varied brake power conditions. Tested fuels were neat diesel, CPOT5 (5% CPO + 5% TU + 90% D), CPOT10 (10% CPO + 5% TU + 85% D) and CPOT15 (15% CPO + 5% TU + 80% D). CPO was extracted through a lab-scale fast pyrolysis apparatus. Fuel samples were prepared and characterized according to ASTM standards. Owing to the features like low sensitivity, impressive anti pinging, etc., presence of toluene in an optimal CPO-diesel blend was expected to promote the engine characteristics. Set of experiments were conducted for each fuel mixture and the respective in-cylinder pressure, fuel consumption, exhaust emission levels, temperatures were recorded. At the rated power output condition, CPOT5 fuel had shown 1.67% increased brake thermal efficiency, 5% reduced brake specific fuel consumption, almost 3% reduced exhaust gas temperatures as well as reduced the exhaust emissions such as HC (from 91 to 87 ppm), CO (from 0.1 to 0.08%), NOx (from 458 to 426 ppm), smoke levels (from 72 to 69 BSN). CPOT5 showed improved combustion characteristics like reduced ignition delays and combustion durations, increased rates of cylinder pressure rise and heat release. However, overall attained improvements in the engine parameters were found to be not up to the mark which makes the chances of using CPOT5 as best alternative to diesel feeble. Article highlights The Cashew nut shells agro-waste is efficiently converted into an alternative fuel. Effect of adding toluene to pyro oil – diesel blends in CI engine is examined. Engine performance is improved marginally with 1.6% higher brake thermal efficiency (BTE) and 5% lower brake specific fuel consumption (BSFC). Reductions in CO, HC, NOx and smoke emissions are observed. Reduced Ignition delay and combustion durations, increased rate of pressure rise, and increased HRR are observed.


Author(s):  
Jiantong Song ◽  
Zhixin Feng ◽  
Jiangyi Lv ◽  
Hualei Zhang

Abstract The pilot diesel injection timing (θ) significantly affects the combustion and performance of dual-fuel (DF) engines. In order to optimize the θ of a natural gas-diesel DF engine, the influence of θ on combustion, cyclic variation, and performance of a diesel engine fueled with natural gas piloted by diesel under full load at 1200 rpm was investigated. The results indicate that, with the advance in θ, the cylinder pressure, rate of pressure rise (ROPR), and heat release rate (HRR) increase first and then decrease. The mean value of peak cylinder pressure (pmax) rises and the standard deviation increases first and then decreases. The distribution of the crank angle of peak cylinder pressure (φ(pmax)) scatters and approaches the top dead center. The coefficient of variation (COV) in pmax decreases first and then increases while the COV in φ(pmax) obviously increases. The brake power increases first and then decreases while the brake specific fuel consumption (b.s.f.c.) reduces first and then rises. The CO2 and NOx emissions rise first and then reduce while smoke emission decreases first and then increases, but the CO and HC rise.


Author(s):  
Jiantong Song ◽  
Guna Wang

Abstract The pilot diesel quantity (mpilot) has an impact on the liqueified nitrogen gas (LNG)-diesel dual-fuel engine, but it is very difficult for a dual-fuel engine with the traditional injection system to adjust mpilot to meet various operating conditions in practice. In recent years, with great progress in common rail diesel injection technology, mpilot can be adjusted accurately by the electronic control system, which is an advantage for operation with the diesel–LNG dual-fuel. In order to optimize mpilot of the diesel–LNG dual-fuel engine, the combustion and performance of a dual-fuel engine with the mpilot of 5.05 mg/cyc, 5.20 mg/cyc, 5.69 mg/cyc, 6.31 mg/cyc and 6.91 mg/cyc under 50% load at speed of 1600 r/min were analyzed. Experimental results show that, with an increase in mpilot, the maximum in-cylinder pressure, rate of pressure rise, and heat release rate of dual-fuel obviously increase, the crank angles of the maximum value move forward, and the combustion duration becomes shorter. The mean value of peak in-cylinder pressure (pmax) increases obviously while the standard deviation of it decreases, and the distribution of that focuses. The mean value of the crank angle corresponding to pmax pressure decreases except for the mpilot of 5.05 mg/cyc, while the standard deviation of that gradually decreases, the distribution of it focuses and moves forward. The brake power increases while the brake-specific fuel consumption (BSFC) decreases, the CO and HC decrease, while the CO2, NOx, and smoke density emissions increase.


Author(s):  
Andrew de Tablan

The abundance of natural gas in the United States and low price relative to diesel fuel has generated interest in dual fuel engines where natural gas is substituted for diesel fuel. The factors limiting the natural gas (NG) substitution rates are: minimum diesel injector pulse width, cycle-to-cycle variation in net indicated mean effective pressure (NIMEP), engine knock, peak cylinder pressure, compression ratio, boost pressure and lean air/fuel limits leading to misfire among others. The objective of this study was to explore the highest natural gas substitution for a commercially available heavy duty diesel engine for several of the 13 Mode European Stationary Cycle (ESC) and US EPA Supplementary Emissions Tests (SET) speeds and loads while maintaining acceptable engine performance levels. A heavy duty 2012 Navistar MaxxForce 13® engine was retrofitted to accommodate dual-fuel operation. The engine was operated over several different speeds and loads to determine the possible NG substitution rates at different diesel injection timings, diesel injection pressures and equivalence ratios, while maintaining combustion phasing. The data showed that dual fuel operation at high NG percentages was stable over several speeds and loads with brake thermal efficiencies comparable to 100% diesel operation. The introduction of NG generally demonstrated reductions in peak cylinder pressure and cylinder pressure rise rate at a given speed and load point. Increases in hydrocarbon and greenhouse gas emissions and a decrease in nitrogen oxides were observed during dual-fuel operation.


Author(s):  
Petar Kazakov ◽  
Atanas Iliev ◽  
Emil Marinov

Over the decades, more attention has been paid to emissions from the means of transport and the use of different fuels and combustion fuels for the operation of internal combustion engines than on fuel consumption. This, in turn, enables research into products that are said to reduce fuel consumption. The report summarizes four studies of fuel-related innovation products. The studies covered by this report are conducted with diesel fuel and usually contain diesel fuel and three additives for it. Manufacturers of additives are based on already existing studies showing a 10-30% reduction in fuel consumption. Comparative experimental studies related to the use of commercially available diesel fuel with and without the use of additives have been performed in laboratory conditions. The studies were carried out on a stationary diesel engine СМД-17КН equipped with brake КИ1368В. Repeated results were recorded, but they did not confirm the significant positive effect of additives on specific fuel consumption. In some cases, the factors affecting errors in this type of research on the effectiveness of fuel additives for commercial purposes are considered. The reasons for the positive effects of such use of additives in certain engine operating modes are also clarified.


2018 ◽  
Vol 4 (2) ◽  
Author(s):  
Soni S. Wirawan dkk

Biodiesel is a viable substitute for petroleum-based diesel fuel. Its advantages are improved lubricity, higher cetane number and cleaner emission. Biodiesel and its blends with petroleum-based diesel fuel can be used in diesel engines without any signifi cant modifi cations to the engines. Data from the numerous research reports and test programs showed that as the percent of biodiesel in blends increases, emission of hydrocarbons (HC), carbon monoxide (CO), and particulate matter (PM) all decrease, but the amount of oxides of nitrogen (NOx) and fuel consumption is tend to increase. The most signifi cant hurdle for broader commercialization of biodiesel is its cost. In current fuel price policy in Indonesia (especially fuel for transportation), the higher percent of biodiesel in blend will increase the price of blends fuel. The objective of this study is to assess the optimum blends of biodiesel with petroleum-based diesel fuel from the technically and economically consideration. The study result recommends that 20% biodiesel blend with 80% petroleum-based diesel fuel (B20) is the optimum blend for unmodifi ed diesel engine uses.Keywords: biodiesel, emission, optimum, blend


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