Novel strategies to overcome the limitations of a low compression ratio light duty diesel engine

2020 ◽  
pp. 146808742096198
Author(s):  
V Vikraman ◽  
K Anand ◽  
A Ramesh
Keyword(s):  
Diesel Engine ◽  
Compression Ratio ◽  
Diesel Engines ◽  
High Speed ◽  
Fuel Injection ◽  
Cooling System ◽  
Parameters Optimization ◽  
Oxides Of Nitrogen ◽  
Load Range ◽  
Soot Emissions

Low compression ratio (LCR) approach in diesel engines can reduce the oxides of nitrogen (NOx) and soot emissions simultaneously owing to lower temperatures and longer fuel-air premixing time. The present work investigates the effects of lowering the geometric compression ratio (CR) from 18:1 to 14:1 in a naturally aspirated (NA) single cylinder common rail direct injection (CRDI) diesel engine. Based on the investigations done across the entire speed and load range, significant benefits were observed in the NOx and soot emissions. However, lowering the compression ratio had adverse effects on brake specific fuel consumption (BSFC), unburned hydrocarbon (HC) and carbon monoxide (CO) emissions, especially at low-load and high-speed operating points. To overcome these limitations, novel strategies including split-cooling system (SCS) and secondary exhaust valve opening (SEVO) are proposed in the present work. While the fuel injection parameters optimization specific to LCR could help to improve the BSFC, HC and CO emissions penalty to a reasonable extent, the SCS concept can provide further benefits by reducing the heat loss to coolant and improving the engine component temperatures. Increasing the residual gas fraction using the optimized SEVO concept could further improve the charge temperature leading to a further reduction in the BSFC, HC and CO emissions. The net benefits of the optimized LCR approach are quantified for the modified Indian drive cycle (MIDC) using a one-dimensional simulation tool. The results obtained show a signification reduction of 22% and 74% in NOx and soot emissions respectively as compared to the base 18 CR engine results. Moreover, the penalty in HC and CO emissions could be contained to a large extent resulting in only a slight penalty of 23% and 20% respectively. Furthermore, the higher BSFC with the LCR approach could be successfully addressed and the final values were found to be better than the stock compression ratio by 1.5%. Overall, the strategies proposed in the present work are found to be beneficial to develop modern diesel engines in compliance with the future emission regulations which demand extreme control on NOx and soot emissions.

scholarly journals MODIFYING MATHEMATICAL MODELS FOR CALCULATING OPERATIONAL CHARACTERISTICS OF DIESEL ENGINES BURNING RME BIOFUELS / MATEMATINIŲ MODELIŲ PRITAIKYMAS DYZELIŲ, DIRBANČIŲ RME BIODEGALAIS, DARBO PROCESUI IR EKSPLOATACINIAMS RODIKLIAMS SKAIČIUOTI / ДОРАБОТКА МАТЕМАТИЧЕСКИХ МОДЕЛЕЙ РАСЧЕТА ПОКАЗАТЕЛЕЙ РАБОТЫ ДИЗЕЛЯ НА БИОДИЗЕЛИНАХ РРМЭ

Transport ◽  
2011 ◽  
Vol 26 (1) ◽  
pp. 50-60 ◽  
Author(s):  
Sergejus Lebedevas ◽  
Galina Lebedeva ◽  
Kristina Bereišienė
Keyword(s):  
Diesel Engine ◽  
Mathematical Modelling ◽  
Mathematical Models ◽  
Diesel Engines ◽  
Fuel Injection ◽  
Internal Heat ◽  
Computer Programs ◽  
Toxic Substances ◽  
Load Range ◽  
Operational Characteristics

The article considers and solves the problems of adapting the mathematical models, used in calculating operational characteristics of diesel engines burning mineral diesel oil, to engines converted to RME biofuels. The analysis of mathematical models of calculating the main technical and economic characteristics of diesel engines as well as the parameters of the in-cylinder process and the concentration of toxic substances in the exhaust gases is performed. The need for adjusting the calculation algorithms is also demonstrated. The computer programs based on single-zone thermodynamic models are used in the research. The programs of mathematical modelling are modified, i.e. supplemented with the algorithm for calculating energy characteristics of the combustion products (e.g. specific heat capacity, internal heat, the lower calorific value, etc.). Based on the computer programs, modified for examining diesel engines burning biofuels, the computer-aided mathematical modelling experiment is carried out. The results of modelling are compared with the data obtained in testing the diesel engine 1A41. The mathematical modelling performed demonstrates the accuracy acceptable for solving practical problems: the difference between the obtained calculation results and diesel engine testing data for the load range of (1.0÷0.5) Pi nom does not exceed ± 5÷7%. Higher accuracy of modelling the characteristics of diesel engines, operating in the low- and medium-load modes, may be accounted for by the adjustment of the algorithm for calculating the induction period and the on-set phase of fuel injection. Santrauka Publikacijoje pateikti dyzelio darbo proceso ir eksploatacinių rodiklių skaičiavimo matematinių modelių tobulinimo rezultatai, siekiant matematinius modelius pritaikyti dyzeliui dirbant riebiųjų rūgščių metilesterių, taip pat RME, biodegalais. Atlikta skaičiavimo algoritmų analizė ir pagrįsti pagrindiniai jų tobulinimo aspektai. Sukurtas kompiuterinis programinis modelis, skirtas darbinio kūno dyzelio cilindre energiniams parametrams skaičiuoti (specifinei šilumai, vidinei energijai), dyzeliui dirbant plačiąja elementinės cheminės sudėties biodegalų gama. Atliktas 1A41 dyzelio techninių ir ekonominių bei ekologinių rodiklių modeliavimas kompiuteriu, naudojant patobulintus matematinius modelius. Parodytas gautų rezultatų, pakankamų praktiniams uždaviniams spręsti, tikslumas: dyzeliui dirbant artimos nominaliosios apkrovos režimais (1,0÷0,5) Pi nom skirtumas tarp skaičiavimo ir dyzelio motorinių tyrimų rezultatų neviršija ±5÷7%. Dyzeliui dirbant mažos apkrovos režimu, matematinio modeliavimo rezultatų adekvatumo didinimas susijęs su kuro įpurškimo fazės bei savaiminio užsiliepsnojimo indukcijos periodo skaičiavimo algoritmo tobulinimu. Резюме Рассмотрены и решены задачи адаптации математических моделей расчета показателей дизеля при переводе их работы с минерального дизелина на биодизелины метилового эфира рапсового масла (МЭРМ). Выполнен анализ и дано обоснование направлений доработки расчетных алгоритмов ряда однозонных термодинамических математических моделей, используемых в практике исследования эксплуатационных показателей, параметров индикаторного процесса и эмиссии токсичных компонентов в выхлопных газах дизелей. В форме программного модуля составлен алгоритм расчета энергетических параметров рабочего тела в цилиндре (удельной теплоемкости, теплоты сгорания, внутренней энергии) для топлив с широким элементарным химическим составом. С использованием доработанных компьютерных программ выполнен широкий расчетный эксперимент и сопоставлены его результаты с данными моторных стендовых испытаний одноцилиндрового отсека дизеля 1А41. Показана приемлемая для решения практических задач точность математического моделирования: для нагрузочных режимов (1÷0,5) Pmi расхождения расчетных и экспериментальных значений параметров работы дизеля не превышают ±5÷7%. Повышение качества моделирования показателей дизеля на режимах средних и малых нагрузок связано с уточнением алгоритма расчета периода индукции и фазы начала видимого горения топлива в цилиндре.

Characteristics of injection of diesel fuel, rapeseed oil and their mixtures in diesel engines of various types

2021 ◽  
pp. 167-178
Author(s):  
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Diesel Engines ◽  
Rapeseed Oil ◽  
High Speed ◽  
Fuel Injection ◽  
Experimental Studies ◽  
Fuel Injector ◽  
High Speed Diesel ◽  
Engine Type

The necessity of adapting diesel engines to work on vegetable oils is justified. The possibility of using rapeseed oil and its mixtures with petroleum diesel fuel as motor fuels is considered. Experimental studies of fuel injection of small high-speed diesel engine type MD-6 (1 Ch 8,0/7,5)when using diesel oil and rapeseed oil and computational studies of auto-tractor diesel engine type D-245.12 (1 ChN 11/12,5), working on blends of petroleum diesel fuel and rapeseed oil. When switching autotractor diesel engine from diesel fuel to rapeseed oil in the full-fuel mode, the mass cycle fuel supply increased by 12 %, and in the small-size high-speed diesel engine – by about 27 %. From the point of view of the flow of the working process of these diesel engines, changes in other parameters of the fuel injection process are less significant. Keywords diesel engine; petroleum diesel fuel; vegetable oil; rapeseed oil; high pressure fuel pump; fuel injector; sprayer

scholarly journals Performance evaluation of common rail direct injection (CRDI) engine fuelled with Uppage Oil Methyl Ester (UOME)

2015 ◽  
Vol 4 (1) ◽  
pp. 1-10 ◽  
Author(s):  
D.N. Basavarajappa ◽  
N. R. Banapurmath ◽  
S.V. Khandal ◽  
G. Manavendra
Keyword(s):  
Diesel Engine ◽  
Methyl Ester ◽  
Diesel Engines ◽  
High Speed ◽  
Alternative Fuels ◽  
High Pressures ◽  
Fuel Injection ◽  
Injection Timing ◽  
Engine Operation ◽  
Performance And Emission

For economic and social development of any country energy is one of the most essential requirements. Continuously increasing price of crude petroleum fuels in the present days coupled with alarming emissions and stringent emission regulations has led to growing attention towards use of alternative fuels like vegetable oils, alcoholic and gaseous fuels for diesel engine applications. Use of such fuels can ease the burden on the economy by curtailing the fuel imports. Diesel engines are highly efficient and the main problems associated with them is their high smoke and NOx emissions.  Hence there is an urgent need to promote the use of alternative fuels in place of high speed diesel (HSD) as substitute. India has a large agriculture base that can be used as a feed stock to obtain newer fuel which is renewable and sustainable. Accordingly Uppage oil methyl ester (UOME) biodiesel was selected as an alternative fuel. Use of biodiesels in diesel engines fitted with mechanical fuel injection systems has limitation on the injector opening pressure (300 bar). CRDI system can overcome this drawback by injecting fuel at very high pressures (1500-2500 bar) and is most suitable for biodiesel fuels which are high viscous. This paper presents the performance and emission characteristics of a CRDI diesel engine fuelled with UOME biodiesel at different injection timings and injection pressures. From the experimental evidence it was revealed that UOME biodiesel yielded overall better performance with reduced emissions at retarded injection timing of -10° BTDC in CRDI mode of engine operation.

Scaling liquid penetration in evaporating sprays for different size diesel engines

2019 ◽  
Vol 21 (9) ◽  
pp. 1662-1677 ◽  
Author(s):  
Xinyi Zhou ◽  
Tie Li ◽  
Yijie Wei ◽  
Ning Wang
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
High Speed ◽  
Scaling Laws ◽  
Fuel Injection ◽  
Pollutant Emissions ◽  
Liquid Penetration ◽  
Spray Characteristics ◽  
Penetration Length ◽  
Air Mixing

Scaled model experiments can greatly reduce the cost, time and energy consumption in diesel engine development, and the similarity of spray characteristics has a primary effect on the overall scaling results of engine performance and pollutant emissions. However, although so far the similarity of spray characteristics under the non-evaporating condition has been studied to some extent, researches on scaling the evaporating sprays are still absent. The maximum liquid penetration length has a close relationship with the spray evaporation processes and is a key parameter in the design of diesel engine spray combustion system. In this article, the similarity of maximum liquid penetration length is theoretically derived based on the hypotheses that the spray evaporation processes in modern high-pressure common rail diesel engines are fuel–air mixing controlled and local interphase transport controlled, respectively. After verifying that the fuel injection rates are perfectly scaled, the similarity of maximum liquid penetration length in evaporating sprays is studied for three scaling laws using two nozzles with hole diameter of 0.11 and 0.14 mm through the high-speed diffused back-illumination method. Under the test conditions of different fuel injection pressures, ambient temperatures and densities, the lift-off law and speed law lead to a slightly increased maximum liquid penetration length, while the pressure law can well scale the maximum liquid penetration length. The experimental results are consistent with the theoretical analyses based on the hypothesis that the spray evaporation processes are fuel–air mixing controlled, indicating that the local interphase transports of energy, momentum and mass on droplet surface are not rate-controlled steps with respect to spray evaporation processes.

A Phenomenological Model for Combustion and Emissions in Small Bore, High Speed, Direct Injection Diesel Engines

2005 ◽  
Author(s):  
N. A. Henein ◽  
I. P. Singh ◽  
L. Zhong ◽  
Y. Poonawala ◽  
J. Singh ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Phenomenological Model ◽  
High Speed ◽  
Gas Flow ◽  
Fuel Injection ◽  
Direct Injection ◽  
Injection System ◽  
Injection Process ◽  
Wide Range

This paper introduces a phenomenological model for the fuel distribution, combustion, and emissions formation in the small bore, high speed direct injection diesel engine. A differentiation is made between the conditions in large bore and small bore diesel engines, particularly regarding the fuel impingement on the walls and the swirl and squish gas flow components. The model considers the fuel injected prior to the development of the flame, fuel injected in the flame, fuel deposited on the walls and the last part of the fuel delivered at the end of the injection process. The model is based on experimental results obtained in a single-cylinder, 4-valve, direct-injection, four-stroke-cycle, water-cooled, diesel engine equipped with a common rail fuel injection system. The engine is supercharged with heated shop air, and the exhaust back pressure is adjusted to simulate actual turbo-charged diesel engine conditions. The experiments covered a wide range of injection pressures, EGR rates, injection timings and swirl ratios. Correlations and 2-D maps are developed to show the effect of combinations of the above parameters on engine out emissions. Emphasis is made on the nitric oxide and soot measured in Bosch Smoke Units (BSU).

A novel strategy of extremely delayed intake valve opening to improve the cold-start characteristics of a low compression ratio diesel engine

2021 ◽  
pp. 146808742110346
Author(s):  
V Vikraman ◽  
K Anand ◽  
A Ramesh
Keyword(s):  
Diesel Engine ◽  
Compression Ratio ◽  
Diesel Engines ◽  
Cold Start ◽  
Stagnation Temperature ◽  
Oxides Of Nitrogen ◽  
Intake Valve ◽  
Air Velocity ◽  
Valve Opening ◽  
Novel Strategy

Combined in-cylinder and after-treatment emission control methods are generally adopted to meet the current stringent emission targets for diesel engines. It is well established that reducing the geometric compression ratio (CR) results in a simultaneous reduction in the oxides of nitrogen (NOx) and soot emissions in diesel engines. However, poor cold-start characteristics prevent extensive use of low compression ratio (LCR) diesel engines for automotive applications. In the present work, a novel extremely delayed intake valve opening (IVO) strategy is proposed to improve the cold-start characteristics of a light-duty LCR diesel engine. A commercial one-dimensional gas-exchange model was used to optimize the intake valve open and close timings. The results corresponding to a cranking speed of 200 rpm and ambient temperature of 0°C show that advancing the intake valve close (IVC) timing increases the effective compression stroke that can improve the cylinder temperature by 5%. Further, implementing ‘extremely delayed IVO’ by retarding the timing from 1°CA to 61°CA aTDC could help to further increase the cylinder temperature by 14% compared to the base timings. The delayed opening of the intake valve leads to a higher expansion of the cylinder mass, leading to a lower cylinder pressure before IVO and a higher intake air velocity immediately after IVO. With the higher intake air velocity, the incoming air’s kinetic energy is dissipated to increase the stagnation temperature, resulting in an overall benefit in cylinder temperature. The experimental measurements conducted in a cold chamber with the optimized IVO and IVC timings confirmed the benefits by achieving a better cold-startability of the LCR engine. In comparison, the LCR engine with the stock valve timings could be started only up to +5°C, the optimized valve timings could ensure startability up to −10°C without any starting aids. Thus, the proposed approach of adopting the optimized valve timings can help LCR diesel engines to overcome the limitations of cold-startability.

scholarly journals Possibilities of Simultaneous In-Cylinder Reduction of Soot andNOxEmissions for Diesel Engines with Direct Injection

2008 ◽  
Vol 2008 ◽  
pp. 1-13 ◽  
Author(s):  
U. Wagner ◽  
P. Eckert ◽  
U. Spicher
Keyword(s):  
Nitrogen Oxide ◽  
Diesel Engines ◽  
Fuel Injection ◽  
Soot Formation ◽  
Soot Oxidation ◽  
The Other ◽  
Injection System ◽  
Nitrogen Oxide Emissions ◽  
Injection Strategy ◽  
Soot Emissions

Up to now, diesel engines with direct fuel injection are the propulsion systems with the highest efficiency for mobile applications. Future targets in reducingCO2-emissions with regard to global warming effects can be met with the help of these engines. A major disadvantage of diesel engines is the high soot and nitrogen oxide emissions which cannot be reduced completely with only engine measures today. The present paper describes two different possibilities for the simultaneous in-cylinder reduction of soot and nitrogen oxide emissions. One possibility is the optimization of the injection process with a new injection strategy the other one is the use of water diesel emulsions with the conventional injection system. The new injection strategy for this experimental part of the study overcomes the problem of increased soot emissions with pilot injection by separating the injections spatially and therefore on the one hand reduces the soot formation during the early stages of the combustion and on the other hand increases the soot oxidation later during the combustion. Another method to reduce the emissions is the introduction of water into the combustion chamber. Emulsions of water and fuel offer the potential to simultaneously reduceNOxand soot emissions while maintaining a high-thermal efficiency. This article presents a theoretical investigation of the use of fuel-water emulsions in DI-Diesel engines. The numerical simulations are carried out with the 3D-CFD code KIVA3V. The use of different water diesel emulsions is investigated and assessed with the numerical model.

scholarly journals Applied science and manufacturing: NAMI and VTZ

2021 ◽  
Vol 1 (2) ◽  
pp. 6-15
Author(s):  
YU.G. Grudskiy ◽  
Keyword(s):  
Diesel Engines ◽  
High Speed ◽  
Fuel Injection ◽  
Vortex Formation ◽  
Flaw Detection ◽  
Added Value ◽  
Manufacturing Cost ◽  
Central Research ◽  
The 1960S ◽  
The Many

Starting from the 1960s, a number of acute problems appeared in the engine building during the transition to diesel engines of a new generation, the engines with direct fuel injection into the chamber in the piston. The short time allotted in the cycle for mixture formation and combustion, especially for high-speed diesel engines, makes it extremely scrupulous to approach this in order to obtain high and stable technical and economic indicators. One of the many problems is the organi-zation of efficient and uniform gas exchange across the samples to reduce the spread of final indica-tors during mass production. The article deals with this very problem, specifically - in the case of chill casting of individual heads at the Vladimir Tractor Plant (VTZ) using composite rods of inlet and outlet channels. The method of static blowing of inlet channels developed at Central research and development automobile and engine institute NAMI with a quantitative assessment of the re-sistance and vortex formation in the cylinder was applied. The gas-dynamic parameters (GP) were checked for the heads that received individual numbers in a statistically significant sample of billets on one test bench several times, sequentially according to the stages of the processing. It is shown schematically how these parameters changed during processing and assembly of the heads. It is im-portant that a high “hereditary” correlation is obtained between the GP of the billets and fully ma-chined and assembled cylinder heads. The manufacturing cost of the latter is incommensurably higher than the castings cost. Therefore, according to the results of the work, in order to reduce the cost of products and increase the level and stability of quality, an important decision was made on the early flaw detection of the GP (after casting) with the subsequent remelting of those blanks that are most likely “genetically, hereditarily” will not provide the declared technical and economic in-dicators in assembled product. Similar approaches can be used in the organization of production and other goods with high added value of technological operations required after procurement to ensure the quality of final products.

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