scholarly journals Effect of Intake Air Temperature and Premixed Ratio on Combustion and Exhaust Emissions in a Partial HCCI-DI Diesel Engine

2021 ◽  
Vol 13 (15) ◽  
pp. 8593
Author(s):  
Yew Heng Teoh ◽  
Hishammudin Afifi Huspi ◽  
Heoy Geok How ◽  
Farooq Sher ◽  
Zia Ud Din ◽  
...  

Homogeneous charge compression ignition (HCCI) is considered an advanced combustion method for internal combustion engines that offers simultaneous reductions in oxides of nitrogen (NOx) emissions and increased fuel efficiency. The present study examines the influence of intake air temperature (IAT) and premixed diesel fuel on fuel self-ignition characteristics in a light-duty compression ignition engine. Partial HCCI was achieved by port injection of the diesel fuel through air-assisted injection while sustaining direct diesel fuel injection into the cylinder for initiating combustion. The self-ignition of diesel fuel under such a set-up was studied with variations in premixed ratios (0–0.60) and inlet temperatures (40–100 °C) under a constant 1600 rpm engine speed with 20 Nm load. Variations in performance, emissions and combustion characteristics with premixed fuel and inlet air heating were analysed in comparison with those recorded without. Heat release rate profiles determined from recorded in-cylinder pressure depicted evident multiple-stage ignitions (up to three-stage ignition in several cases) in this study. Compared with the premixed ratio, the inlet air temperature had a greater effect on low-temperature reaction and HCCI combustion timing. Nonetheless, an increase in the premixed ratio was found to be influential in reducing nitric oxides emissions.

Author(s):  
Swami Nathan Subramanian ◽  
Stephen Ciatti

The conventional combustion processes of Spark Ignition (SI) and Compression Ignition (CI) have their respective merits and demerits. Internal combustion engines use certain fuels to utilize those conventional combustion technologies. High octane fuels are required to operate the engine in SI mode, while high cetane fuels are preferable for CI mode of operation. Those conventional combustion techniques struggle to meet the current emissions norms while retaining high efficiency. In particular, oxides of nitrogen (NOx) and particulate matter (PM) emissions have limited the utilization of diesel fuel in compression ignition engines, and conventional gasoline operated SI engines are not fuel efficient. Advanced combustion concepts have shown the potential to combine fuel efficiency and improved emissions performance. Low Temperature Combustion (LTC) offers reduced NOx and PM emissions with comparable modern diesel engine efficiencies. The ability of premixed, low-temperature compression ignition to deliver low PM and NOx emissions is dependent on achieving optimal combustion phasing. Variations in injection pressures, injection schemes and Exhaust Gas Recirculation (EGR) are studied with low octane gasoline LTC. Reductions in emissions are a function of combustion phasing and local equivalence ratio. Engine speed, load, EGR quantity, compression ratio and fuel octane number are all factors that influence combustion phasing. Low cetane fuels have shown comparable diesel efficiencies with low NOx emissions at reasonably high power densities.


Author(s):  
S. Mathavan ◽  
T. Mothilal ◽  
V. Andal ◽  
V. Velukumar

The invention of internal combustion engines is undoubtedly one of the greatest inventions of the modern era. There has been steady scientific research to look for alternative fuel which is economical, renewable and less harmful to nature and man compared to fossil fuels. The present project is one such experimental work to investigate the performance of a blend of diesel / N-pentanol in an appropriate combustion technique and to establish its suitability as a renewable fuel. The relative performance of diesel fuel and the blend of diesel / n-pentanol will also be analyzed. Diesel fuel blended with 30 percentage n-pentanol is the fuel blend that is proposed to be used in the experiment. Researchers have established that the application of Homogeneously Charged Compression Ignition (HCCI) technique could result in in-cylinder reduction of NOx and PM. Higher thermal efficiency could also be attained. The project also covers studying the emission effect of the diesel/n-pentanol fuel blend for various fuel injection timing, various fuel injection pressure, different EGR rates and different inlet air temperature.


Author(s):  
Gong Chen

Present-day high-power compression-ignition engines are required in design not only to achieve a targeted high fuel efficiency, but also to meet regulated exhaust emissions standards. This paper investigates the effects of the in-cylinder combustion related design parameters, including cylinder compression ratio, fuel injection-start timing, and the amount of cylinder air charge, on engine performances and emissions as the engine structure-loading allowance is specified. Thereby the determination of those parameters to optimize the engine overall performances without exceeding the allowances in engine mechanical and thermal loading can be achieved. An enhanced understanding of those design parameters associated with the engine structural loading parameters, such as the cylinder peak firing pressure and exhaust temperature, is studied. The analytical prediction of the trade-off between those parameters with peak firing pressure contained is modeled and developed.


2013 ◽  
Vol 440 ◽  
pp. 254-259 ◽  
Author(s):  
S. Natarajan ◽  
N.V. Mahalakshmi ◽  
S. Sundarraj

This paper deals with the experimental investigation of a Homogeneous Charge Compression Ignition (HCCI) Engine system. The main objective of this research work is to study the effects of a premixed fuel ratio on the performance, combustion characteristics and reduction of oxides of nitrogen and smoke intensity, using the HCCI concept. The engine used for the experiments was of a Kirloskar TAF-I series. The engine is a four stroke, single cylinder air cooled diesel engine, of a rated power of 4.4 kW loaded with an electrical dynamometer. An electronic fuel injection circuit was developed to control the ignition timing and duration of the premixed charge. Ethanol was premixed, and a part injected before ignition, whereas the diesel fuel was injected by the conventional injector directly into the cylinder. The part injected ethanol and direct injected diesel were tested in various proportions, to optimize the operating range, and the same setup was tested with various % of EGR.The obtained results include data plots illustrating the performance, combustion and emission characteristics. The results indicate that the concentration of the oxides of nitrogen species rapidly decreased, and the smoke emissions were reduced simultaneously at 20% Rp and 20% EGR in 75% load and full load conditions.


2005 ◽  
Vol 128 (3) ◽  
pp. 497-505 ◽  
Author(s):  
Dae Sik Kim ◽  
Myung Yoon Kim ◽  
Chang Sik Lee

In order to obtain the reduction effect of NOx and soot emission in a partial homogeneous charge compression ignition engine, premixed fuel was supplied with direct injection diesel fuel. Several additional systems such as a premixed fuel injection system, exhaust gas recirculation (EGR) system, supercharger, and air heating system were equipped in the intake manifold of conventional diesel engine. Premixed fuel with air was compressed and ignited by the directly injected diesel fuel in the combustion chamber at the end of compression stroke. The effect of premixed fuel on combustion and emission characteristics of HCCI diesel engine was investigated experimentally under various conditions of intake air temperature, pressure, and EGR rate. The results showed that in case of the use of gasoline as a premixed fuel, single stage ignition is found, but premixing the diesel fuel accompanies the cool flame prior to the combustion of the directly injected diesel fuel. For the gasoline premixed fuel, both NOx and soot can be reduced by the increase of premixed ratio simultaneously. However, for the diesel premixed fuel, the increase of premixed ratio does not have a significant effect in reducing the soot emission.


Inorganic nanotubes are attracting the attention of many scientists and investigators, due to their outstanding application potential in different fields. Researches have been performed in the field of internal combustion engines by adding nanoparticles into the diesel fuel and in biodiesel and blends and their effect on overall performance were studied. It is understood that doping of nanoparticles tend to decrease the emission levels from the engines. Owing to that idea, this project is directed to investigate the effect of doping nanoparticle over the performance and emission characteristics of a compression ignition engine. Nanotubes are mixed with diesel fuel as a fuel additive at different compositions that are 25 ppm, 50 ppm, 100 ppm to find the variation in performance and emission characteristics and results indicate that nanoparticle doped fuel shall be used as an alternate fuel without any modifications to engine structure.


2021 ◽  
pp. 146808742098626
Author(s):  
Pooyan Kheirkhah ◽  
Patrick Kirchen ◽  
Steven Rogak

Exhaust-stream particulate matter (PM) emission from combustion sources such as internal combustion engines are typically characterized with modest temporal resolutions; however, in-cylinder investigations have demonstrated significant variability and the importance of individual cycles in transient PM emissions. Here, using a Fast Exhaust Nephelometer (FEN), a methodology is developed for measuring the cycle-specific PM concentration at the exhaust port of a single-cylinder research engine. The measured FEN light-scattering is converted to cycle-resolved soot mass concentration ([Formula: see text]), and used to characterize the variability of engine-out soot emission. To validate this method, exhaust-port FEN measurements are compared with diluted gravimetric PM mass and scanning mobility particle sizer (SMPS) measurements, resulting in close agreements with an overall root-mean-square deviation of better than 30%. It is noted that when PM is sampled downstream in the exhaust system, the particles are larger by 50–70 nm due to coagulation. The response time of the FEN was characterized using a “skip-firing” scheme, by enabling and disabling the fuel injection during otherwise steady-state operation. The average response time due to sample transfer and mixing times is 55 ms, well below the engine cycle period (100 ms) for the considered engine speeds, thus suitable for single-cycle measurements carried out in this work. Utilizing the fast-response capability of the FEN, it is observed that cycle-specific gross indicated mean effective pressure (GIMEP) and [Formula: see text] are negatively correlated ([Formula: see text]: 0.2–0.7), implying that cycles with lower GIMEP emit more soot. The physical causes of this association deserve further investigation, but are expected to be caused by local fuel-air mixing effects. The averaged exhaust-port [Formula: see text] is similar to the diluted gravimetric measurements, but the cycle-to-cycle variations can only be detected with the FEN. The methodology developed here will be used in future investigations to characterize PM emissions during transient engine operation, and to enable exhaust-stream PM measurements for optical engine experiments.


Author(s):  
Yuanjiang Pei ◽  
Marco Mehl ◽  
Wei Liu ◽  
Tianfeng Lu ◽  
William J. Pitz ◽  
...  

A mixture of n-dodecane and m-xylene is investigated as a diesel fuel surrogate for compression ignition (CI) engine applications. Compared to neat n-dodecane, this binary mixture is more representative of diesel fuel because it contains an alkyl-benzene which represents an important chemical class present in diesel fuels. A detailed multicomponent mechanism for n-dodecane and m-xylene was developed by combining a previously developed n-dodecane mechanism with a recently developed mechanism for xylenes. The xylene mechanism is shown to reproduce experimental ignition data from a rapid compression machine (RCM) and shock tube (ST), speciation data from the jet stirred reactor and flame speed data. This combined mechanism was validated by comparing predictions from the model with experimental data for ignition in STs and for reactivity in a flow reactor. The combined mechanism, consisting of 2885 species and 11,754 reactions, was reduced to a skeletal mechanism consisting 163 species and 887 reactions for 3D diesel engine simulations. The mechanism reduction was performed using directed relation graph (DRG) with expert knowledge (DRG-X) and DRG-aided sensitivity analysis (DRGASA) at a fixed fuel composition of 77% of n-dodecane and 23% m-xylene by volume. The sample space for the reduction covered pressure of 1–80 bar, equivalence ratio of 0.5–2.0, and initial temperature of 700–1600 K for ignition. The skeletal mechanism was compared with the detailed mechanism for ignition and flow reactor predictions. Finally, the skeletal mechanism was validated against a spray flame dataset under diesel engine conditions documented on the engine combustion network (ECN) website. These multidimensional simulations were performed using a representative interactive flame (RIF) turbulent combustion model. Encouraging results were obtained compared to the experiments with regard to the predictions of ignition delay and lift-off length at different ambient temperatures.


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