scholarly journals Application of the F-statistic of the Fisher-Snedecor distribution to analyze the significance of the effect of changes in the compression ratio of a diesel engine on the value of the specific enthalpy of the exhaust gas flow

2021 ◽  
Author(s):  
Patrycja Puzdrowska

The paper discusses the impact of changes in the compression ratio on the operating parameters of a diesel engine, e.g. on the temperature of exhaust gases. It presents the construction of the laboratory test stand, on which experimental measurements were realized. It is characterized how the actual changes of the compression ratio were introduced to the existing engine. The program of experimental investigations taking into account the available test stand and measurement possibilities was described. A statistical and qualitative analysis of the obtained measurement results was made. The use of F statistics of the Fisher-Snedecor distribution was proposed to assess the significance of the effect of compression ratio changes on the specific enthalpy of the exhaust gas stream. The specific enthalpy of exhaust gases was analysed for one cycle of diesel engine work, determined on the basis of the course of quickly varying temperature of exhaust gases. The results of these analyses are discussed and the utilitarian purpose of this type of evaluation in parametric diagnostics of piston engines is presented.

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402098840
Author(s):  
Mohammed S Gad ◽  
Sayed M Abdel Razek ◽  
PV Manu ◽  
Simon Jayaraj

Experimental work was done to examine the impact of diesel fuel with alumina nanoparticles on combustion characteristics, emissions and performance of diesel engine. Alumina nanoparticles were mixed with crude diesel in various weight fractions of 20, 30, and 40 mg/L. The engine tests showed that nano alumina addition of 40 ppm to pure diesel led to thermal efficiency enhancement up to 5.5% related to the pure diesel fuel. The average specific fuel consumption decrease about neat diesel fuel was found to be 3.5%, 4.5%, and 5.5% at dosing levels of 20, 30, and 40 ppm, respectively at full load. Emissions of smoke, HC, CO, and NOX were found to get diminished by about 17%, 25%, 30%, and 33%, respectively with 40 ppm nano-additive about diesel operation. The smaller size of nanoparticles produce fuel stability enhancement and prevents the fuel atomization problems and the clogging in fuel injectors. The increase of alumina nanoparticle percentage in diesel fuel produced the increases in cylinder pressure, cylinder temperature, heat release rate but the decreases in ignition delay and combustion duration were shown. The concentration of 40 ppm alumina nanoparticle is recommended for achieving the optimum improvements in the engine’s combustion, performance and emission characteristics.


2018 ◽  
Vol 20 (1) ◽  
pp. 141-154 ◽  
Author(s):  
P Maniatis ◽  
U Wagner ◽  
T Koch

A manipulation of the charge exchange allows controlling the amount of residual gas during engine warm-up. The residual gas during the warm-up phase leads to an increase of the exhaust gas temperature and supports to reach the exhaust after-treatment system operating temperature faster. In addition, the warm residual gas increases the combustion chamber temperature, which reduces the HC and CO emissions. However, fuel consumption increases. For that reason, such heating measures should be the best compromise of both, exhaust gas temperature increase and engine efficiency, in order to provide efficient heating strategies for passenger car diesel engines. Therefore, simulative and experimental investigations are carried out at the Institute of Internal Combustion Engines of the Karlsruhe Institute of Technology to establish a reliable cam design methodology. For the experimental investigations, a modern research single-cylinder diesel engine was set up on a test bench. In addition, a one-dimensional simulation model of the experimental setup was created in order to simulate characteristics of valve lift curves and to investigate their effects on the exhaust gas temperature and the exhaust gas enthalpy flow. These simulations were based on design of experiments (DoE), so that all characteristics can be used sustainably for modeling and explaining their influences on the engine operation. This methodology allows numerically investigating promising configurations and deriving cam contours which are manufactured for testing. To assess the potential of these individual configurations, the results obtained were compared with each other as well as with the series configuration. Results show that the combination of DoE and one-dimensional simulation for the design of camshaft contours is well suited which was also validated with experimental results. Furthermore, the potential of residual gas retention by favorable configurations with a second event already revealed in various publications could be confirmed with respect to exhaust gas temperature increase and engine efficiency.


Author(s):  
Bibhuti B. Sahoo ◽  
Niranjan Sahoo ◽  
Ujjwal K. Saha

Synthesis gas (Syngas), a mixture of hydrogen and carbon monoxide, can be manufactured from natural gas, coal, petroleum, biomass, and even from organic wastes. It can substitute fossil diesel as an alternative gaseous fuel in compression ignition engines under dual fuel operation route. Experiments were conducted in a single cylinder, constant speed and direct injection diesel engine fuelled with syngas-diesel in dual fuel mode. The engine is designed to develop a power output of 5.2 kW at its rated speed of 1500 rpm under variable loads with inducted syngas fuel having H2 to CO ratio of 1:1 by volume. Diesel fuel as a pilot was injected into the engine in the conventional manner. The diesel engine was run at varying loads of 20, 40, 60, 80 and 100%. The performance of dual fuel engine is assessed by parameters such as thermal efficiency, exhaust gas temperature, diesel replacement rate, gas flow rate, peak cylinder pressure, exhaust O2 and emissions like NOx, CO and HC. Dual fuel operation showed a decrease in brake thermal efficiency from 16.1% to a maximum of 20.92% at 80% load. The maximum diesel substitution by syngas was found 58.77% at minimum exhaust O2 availability condition of 80% engine load. The NOx level was reduced from 144 ppm to 103 ppm for syngas-diesel mode at the best efficiency point. Due to poor combustion efficiency of dual fuel operation, there were increases in CO and HC emissions throughout the range of engine test loads. The decrease in peak pressure causes the exhaust gas temperature to rise at all loads of dual fuel operation. The present investigation provides some useful indications of using syngas fuel in a diesel engine under dual fuel operation.


2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Saravanan Duraiarasan ◽  
Rasoul Salehi ◽  
Anna Stefanopoulou ◽  
Siddharth Mahesh ◽  
Marc Allain

Abstract Stringent NOX emission norm for heavy duty vehicles motivates the use of predictive models to reduce emissions of diesel engines by coordinating engine parameters and aftertreatment. In this paper, a physics-based control-oriented NOX model is presented to estimate the feedgas NOX for a diesel engine. This cycle-averaged NOX model is able to capture the impact of all major diesel engine control variables including the fuel injection timing, injection pressure, and injection rate, as well as the effect of cylinder charge dilution and intake pressure on the emissions. The impact of the cylinder charge dilution controlled by the engine exhaust gas recirculation (EGR) in the highly diluted diesel engine of this work is modeled using an adiabatic flame temperature predictor. The model structure is developed such that it can be embedded in an engine control unit without any need for an in-cylinder pressure sensor. In addition, details of this physics-based NOX model are presented along with a step-by-step model parameter identification procedure and experimental validation at both steady-state and transient conditions. Over a complete federal test procedure (FTP) cycle, on a cumulative basis the model prediction was more than 93% accurate.


2018 ◽  
Vol 7 (4.36) ◽  
pp. 920
Author(s):  
Byshov N.V ◽  
Bachurin A.N ◽  
Bogdanchikov I.Yu ◽  
Oleynik D.O ◽  
Yakunin Yu.V. ◽  
...  

The aim of the article is to develop a method and a device for reducing the toxicity of exhaust gases of diesel engines and reducing noise taking into account the current mode of operation of the engine. This is done with the help of installing a liquid catalyst (LC) into the exhaust system, ensuring the processes of trapping, chemical bonding and neutralization of toxic components and soot particles in the aerosol chamber while the vortex flow is being processed by a neutralizing solution supplied under pressure. Then the flow is divided into phases and toxic components and soot are separated in the centrifugal swirl drop separator (SDS).The developed and tested design of an exhaust gas cleaning device installed instead of the standard D-120 engine exhaust system and an automated cleaning process control system make it possible to reduce the toxicity of exhaust gases (EG): nitrogen oxides by 40 %, hydrocarbons by 43 % and soot by 70 %. The noise level of its work in enclosed spaces was reduced by 16–22 %. The device also had low gas-dynamic resistance.The investigation methodology is based on the use of modern methods and measuring devices. Exhaust gas tester META “Autotest CO – CH – CO2 – O2 – λ – NOx” was used to measure the toxicity of exhaust gases. To measure smoking at the exhaust of the diesel engine, the opacity meter META-01MP was used. The gas flow velocity was measured with ATT-1004 thermo-anemometer, the noise level of the tractor was recorded with noise and vibration meter VSHV–003–M2, and the fuel consumption with SIRT-1 meter.Theoretical studies were carried out on the basis of the laws of gas dynamics, the modern theory of statistical analysis, and experiment planning techniques. When developing an experimental LC model, dependencies were obtained, which allow to achieve the optimal design and technological parameters of the wet cleaning system for diesel exhaust gases.The optimization of the design parameters and the processing of experimental data were carried out with the help of modern software using the methods of mathematical statistics using computers.The current methods of reducing the toxicity of engines consist primarily in improving the design of engines, in order to influence the nature of the working process, the use of alternative fuels and additives, exhaust gas recirculation, as well as installing various types of exhaust gas catalytic systems. Measures related to the introduction of constructive changes in engines require some major restructuring of the industry, which is difficult to achieve in modern conditions. Alternative fuels have not yet been widely used in agriculture. Therefore, today the most effective and acceptable means of achieving environmental standards is the installation of various mobile catalysts in the exhaust system, as well as devices for trapping soot particles. The use of this exhaust gas cleaning system for diesel engines functioning in enclosed spaces can significantly improve the working conditions of the personnel and have a slight effect on the power and fuel-economic performance of the power unit, reducing the power of the D-120 engine of the T-30 tractor equipped with an upgraded exhaust system when taking external speed characteristics averaged 1.6 %, the torque was 1.5 % and the increase in specific fuel consumption was 1.8 %.In this paper we used materials from scientific publications indexed by bibliographic abstract databases of Scopus and Web of Science.   


2017 ◽  
Vol 171 (4) ◽  
pp. 269-273
Author(s):  
Jerzy CISEK

This paper presents the results of the diesel engine research on the energy performance, components of exhaust gases and smoke and parameters related to the supply system for VW 1.9 TDI working in 2 modes: with standard, non-cooled EGR system, and without this system. All of measurements were carried out on the some engine speed – 2000 rpm (speed of maximum engine torque) and various engine loads. It was found that the serial engine control unit switches the EGR system off above 150 Nm engine load (Momax = 295 Nm). In this range of load the engine running with EGR is characterized by higher fuel consumption (lower total efficiency) ca. 5%, compared with engine without EGR. Concentration of NOx in exhaust gases was lower up to 45% but, at the same time, exhaust gas smoke and concentration of carbon oxides were strongly increasing. It can be seen that EGR system increases the temperature (up to 110oC) and changes the composition of air-exhaust gas in the intake manifold. One of reason of this fact is self-changing start of injection. Additional effect of EGR is lower air pressure behind turbocharger, because the flow of exhaust gases (into EGR) is taken before the


2020 ◽  
Vol 14 (1) ◽  
pp. 6285-6294
Author(s):  
R. Arias Gilart ◽  
M. R. B. Ungaro ◽  
C. E. A. Rodríguez ◽  
J. F. F. Hernández ◽  
M. C. Sofia ◽  
...  

In this research, different magnetic treatments were applied to diesel fuel using static magnetic fields of 0.36T of magnetic induction. The magnetic conditioners (MCs) were installed in different positions of the fuel lines in the engine and the magnetic treatment of the diesel was also carried out before introducing it into the engine tanks. The study was conducted using a four-stroke, two-cylinder, Lister Petter (LPWS2) engine with a compression ratio of 23.5:1 and a constant engine speed of 1500 rpm. The emissions of carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2), nitrogen oxides and the temperature of the exhaust gases and the mass consumption of fuel were measured. The highest levels of reduction were achieved with the magnetic treatments that locate the MC directly in the engine's pipes. As the number of MC in the engine pipes increases, the emissions of polluting gases decrease. With the treatment that locates one MC in front of each injector, two MC at the entrance of the filter and two MC in the return of fuel were able to increase the O2 emissions by 6.9% and decrease the CO emissions in about 21.3% in the last load of the generator set. With this treatment a decrease in fuel consumption of 4.89% to 80% of engine load was obtained.


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