Diesel Engine Simulations and Experiments: Fuel Variability Effects on Ignition

2014 ◽  
Author(s):  
Mingdi Huang ◽  
Sandeep Gowdagiri ◽  
Xander M. Cesari ◽  
Matthew A. Oehlschlaeger
Keyword(s):  
Diesel Engine ◽  
Cfd Simulation ◽  
Cetane Number ◽  
Engine Performance ◽  
Reaction Model ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Cfd Simulations ◽  
Compression Ignition Engines ◽  
Global Reaction

The chemical composition and properties of fuels used in compression-ignition engines can influence engine performance significantly. Consequently, the modeling of fuel chemistry within computational fluid dynamics (CFD) simulations of diesel and other compression ignition engines is important. Modern detailed chemical mechanisms may provide predictive modeling of fuel chemistry; however, they are generally far too computationally expensive for use in CFD. We present simulations of diesel engine combustion, focusing on the prediction of ignition, using the CONVERGE CFD software package. A CFD simulation framework with models for turbulence and spray breakup and atomization is presented with a reduced global reaction model to describe fuel oxidation and ignition. The global reaction model incorporates a single parameter, the derived cetane number (DCN), to describe fuel reactivity variability. CFD simulations are compared to experiments carried out in a single-cylinder diesel engine for compositionally diverse conventional and alternative diesel and jet fuels. Model-experiment comparisons show general agreement for ignition timing and the influence of fuel variability on ignition timing. In addition, the sensitivity of CFD predictions on the chemistry, turbulence, and spray models is illustrated.

Study of High Load Operation Limit Expansion for Gasoline Compression Ignition Engines

2006 ◽  
Vol 128 (2) ◽  
pp. 377-387 ◽  
Author(s):  
Koudai Yoshizawa ◽  
Atsushi Teraji ◽  
Hiroshi Miyakubo ◽  
Koichi Yamaguchi ◽  
Tomonori Urushihara
Keyword(s):  
Fuel Injection ◽  
Control Method ◽  
Combustion Process ◽  
High Load ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Timing Control ◽  
Load Range ◽  
Compression Ignition Engines ◽  
Spark Plug

In this research, combustion characteristics of gasoline compression ignition engines have been analyzed numerically and experimentally with the aim of expanding the high load operation limit. The mechanism limiting high load operation under homogeneous charge compression ignition (HCCI) combustion was clarified. It was confirmed that retarding the combustion timing from top dead center (TDC) is an effective way to prevent knocking. However, with retarded combustion, combustion timing is substantially influenced by cycle-to-cycle variation of in-cylinder conditions. Therefore, an ignition timing control method is required to achieve stable retarded combustion. Using numerical analysis, it was found that ignition timing control could be achieved by creating a fuel-rich zone at the center of the cylinder. The fuel-rich zone works as an ignition source to ignite the surrounding fuel-lean zone. In this way, combustion consists of two separate auto-ignitions and is thus called two-step combustion. In the simulation, the high load operation limit was expanded using two-step combustion. An engine system identical to a direct-injection gasoline (DIG) engine was then used to validate two-step combustion experimentally. An air-fuel distribution was created by splitting fuel injection into first and second injections. The spark plug was used to ignite the first combustion. This combustion process might better be called spark-ignited compression ignition combustion (SI-CI combustion). Using the spark plug, stable two-step combustion was achieved, thereby validating a means of expanding the operation limit of gasoline compression ignition engines toward a higher load range.

scholarly journals Stochastic parcel tracking in an Euler-Lagrange compartment model for fast simulation of fermentation processes

2021 ◽  
Author(s):  
Cees Haringa ◽  
Wenjun Tang ◽  
Henk Noorman
Keyword(s):  
Cellular Response ◽  
Cfd Simulation ◽  
Mixing Time ◽  
Compartment Model ◽  
Reaction Model ◽  
Heterogeneous Environments ◽  
Cfd Simulations ◽  
Fermentation Processes ◽  
Spatially Resolved ◽  
Unit Operations

Compartment modeling (CM) is a well-known approach for computationally affordable, spatially-resolved hydrodynamic modeling of unit operations. Recent implementations use flow profiles based on CFD simulations, and several authors included microbial kinetics to simulate gradients in bioreactors. However, these studies relied on black-box kinetics, that do not account for intra-cellular changes and cell population dynamics in response to heterogeneous environments. In this paper, we report the implementation of a Lagrangian reaction model, where the microbial phase is tracked as a set of biomass-parcels, each linked with an intra-cellular composition vector and a structured reaction model describing their intra-cellular response to extracellular variations. A stochastic parcel tracking approach is adopted, in contrast to the resolved trajectories used in prior CFD implementations. A penicillin production process is used as a case-study. We show good performance of the model compared to full CFD simulations, both regarding the extra-cellular gradients and intra-cellular pool response, provided the mixing time in the CM matches the full CFD simulation; taking into account that the mixing time is sensitive to the number of compartments. The sensitivity of the model output towards some of the inputs is explored. The coarsest representative CM requires a few minutes to solve 80 hours of flow time, compared to approx. 2 weeks for a full Euler-Lagrange CFD simulation of the same case. This alleviates one of the major bottlenecks for the application of such CFD simulations towards analysis and optimization of industrial fermentation processes.

ETHANOL–BIODIESEL–DIESEL BLENDS AS A DIESEL EXTENDER OPTION ON COMPRESSION IGNITION ENGINES

Transport ◽  
2011 ◽  
Vol 26 (3) ◽  
pp. 303-309 ◽  
Author(s):  
Máté Zöldy
Keyword(s):  
Fossil Fuels ◽  
Cetane Number ◽  
Oil Industry ◽  
Diesel Oil ◽  
Compression Ignition ◽  
Compression Ignition Engines ◽  
Fuel Demand ◽  
Oil Mixtures ◽  
Increasing Demand ◽  
Natural Reserves

Increasing fuel demand, decreasing natural reserves and environmental consciousness have together led to testing and implementing new fuels and blending components of compression ignition engines. Biofuels are very commonly added to fossil fuels, mostly ethanol to gasoline and FAME to diesel. Harmonizing their properties with engines is a great challenge for automotive and oil industry. Increasing demand for diesel oil in Europe raised the question about the possibility of increasing the amount of bio extenders. There were and certainly there are a number of experiments aimed at substituting or blending diesel with other fuels. One group of such fuels makes bioethanol– biodiesel–diesel oil mixtures. The paper proposes a global overview on literature and presents the obtained results. The article explores the possibility of using bioethanol–biodiesel–diesel oil mixtures in vehicles and agricultural compression ignition engines. The main aspect of researches was to find blends substitutable for compression ignition engines. Investigations were made to determine the maximum volume of a renewable part thus reaching the same or similar power output with lowering emissions. The received results were used for environmental and economical investigations. The valorisation of the results shows that bioethanol–biodiesel–diesel blends fulfil the cetane number, viscosity and lubricity requirements for standard diesel. Practical measurements and engine tests show that the utilization of a new fuel decreases emissions from the engine. The results of agricultural feedstock calculation indicate that in Hungary the biofuel part of the investigated fuels can be produced from an overflow.

scholarly journals EFFECTS OF THE USE OF D-LIMONENE AS AN ADDITIVE TO DIESEL-BIODIESEL BLENDS ON EXHAUST GASES COMPOSITION OF COMPRESSION IGNITION ENGINES

2018 ◽  
Vol 17 (2) ◽  
pp. 33
Author(s):  
L. F. Micheli ◽  
D. L. Módolo ◽  
L. E. R. Pereira
Keyword(s):  
Methyl Esters ◽  
Cetane Number ◽  
Specific Weight ◽  
Diesel Oil ◽  
Lubricating Oil ◽  
Low Grade ◽  
Exhaust Gas ◽  
Compression Ignition ◽  
Fuel Injectors ◽  
Compression Ignition Engines

The transesterification of vegetable oils results in methyl esters of fatty acid, known as biodiesel. This one presents similar features of diesel oil, such as cetane number, specific weight, heat of combustion and air-fuel ratio. However, arising problems from its higher viscosity leads to a poor spraying by the fuel injectors and so to a low-grade combustion, causing formation of undesirable deposits inside the engine, changes in the properties of the lubricating oil and in the composition of the exhaust gas. Owing to this issue, it is necessary to study an additive able to make biodiesel characteristics more appropriate to be used in compression ignition engines, as well as a monitoring of changes in exhaust gas composition. The chosen additive was d-limonene, a monocyclic terpene obtained as a byproduct of citriculture. This paper presents the preliminary results obtained from the tests in a stationary diesel engine fuelled with mixtures of diesel-biodiesel and d-limonene, in different concentrations, comparing to regular diesel fuel. Although it was used in low concentrations, the additive was efficient in the reduction of hydrocarbons, carbon monoxide and opacity.

scholarly journals Modification of a Direct Injection Diesel Engine in Improving the Ignitability and Emissions of Diesel–Ethanol–Palm Oil Methyl Ester Blends

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2644 ◽  
Author(s):  
Norhidayah Mat Taib ◽  
Mohd Radzi Abu Mansor ◽  
Wan Mohd Faizal Wan Mahmood
Keyword(s):  
Diesel Engine ◽  
Methyl Ester ◽  
Ambient Temperature ◽  
Palm Oil ◽  
Compression Ratio ◽  
Direct Injection ◽  
Cetane Number ◽  
Engine Performance ◽  
Injection Timing ◽  
Injection Strategies

Blending diesel with biofuels, such as ethanol and palm oil methyl ester (PME), enhances the fuel properties and produces improved engine performance and low emissions. However, the presence of ethanol, which has a small cetane number and low heating value, reduces the fuel ignitability. This work aimed to study the effect of injection strategies, compression ratio (CR), and air intake temperature (Ti) modification on blend ignitability, combustion characteristics, and emissions. Moreover, the best composition of diesel–ethanol–PME blends and engine modification was selected. A simulation was also conducted using Converge CFD software based on a single-cylinder direct injection compression ignition Yanmar TF90 engine parameter. Diesel–ethanol–PME blends that consist of 10% ethanol with 40% PME (D50E10B40), D50E25B25, and D50E40B10 were selected and conducted on different injection strategies, compression ratios, and intake temperatures. The results show that shortening the injection duration and increasing the injected mass has no significant effect on ignition. Meanwhile, advancing the injection timing improves the ignitability but with weak ignition energy. Therefore, increasing the compression ratio and ambient temperature helps ignite the non-combustible blends due to the high temperature and pressure. This modification allowed the mixture to ignite with a minimum CR of 20 and Ti of 350 K. Thus, blending high ethanol contents in a diesel engine can be applied by advancing the injection, increasing the CR, and increasing the ambient temperature. From the emission comparison, the most suitable mixtures that can be operated in the engine without modification is D50E25B25, and the most appropriate modification on the engine is by increasing the ambient temperature at 350 K.

Predicted Qualitative Effects of Alternate Liquid Fuels on Heavy-Duty Compression-Ignition Engines

2009 ◽  
Author(s):  
Gong Chen
Keyword(s):  
Fuel Injection ◽  
Cetane Number ◽  
Fuel Properties ◽  
Liquid Fuels ◽  
Compression Ignition ◽  
Heavy Duty ◽  
Compression Ignition Engine ◽  
End Effects ◽  
Compression Ignition Engines ◽  
The Impact

It is always desirable for a heavy-duty compression-ignition engine, such as a diesel engine, to possess a capability of using alternate liquid fuels without significant hardware modification to the engine baseline. Because fuel properties vary between various types of liquid fuels, it is important to understand the impact and effects of the fuel properties on engine operating and output parameters. This paper intends and attempts to achieve that understanding and to predict the qualitative effects by studying analytically and qualitatively how a heavy-duty compression-ignition engine would respond to the variation of fuel properties. The fuel properties considered in this paper mainly include the fuel density, compressibility, heating value, viscosity, cetane number, and distillation temperature range. The qualitative direct and end effects of the fuel properties on engine bulk fuel injection, in-cylinder combustion, and outputs are analyzed and predicted. Understanding these effects can be useful in analyzing and designing a compression-ignition engine for using alternate liquid fuels.

Utilisation of Cashew Seed Oil Methyl Ester in Compression Ignition Engines and its Engine Performance

2012 ◽  
Vol 3 (2) ◽  
pp. 97 ◽  
Author(s):  
F.I. Otu ◽  
E.I. Bello ◽  
S.K. Otoikhian ◽  
B. Diamond ◽  
L.O. Ekebafe
Keyword(s):  
Methyl Ester ◽  
Seed Oil ◽  
Engine Performance ◽  
Compression Ignition ◽  
Compression Ignition Engines
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