Thermo-Fluid Dynamic Simulation of a S.I. Single-Cylinder H2 Engine and Comparison With Experimental Data

Author(s):  
G. D’Errico ◽  
A. Onorati ◽  
S. Ellgas ◽  
A. Obieglo

This paper deals with the modelling and experimental work carried out on a BMW single cylinder spark ignition hydrogen engine. The authors have enhanced a 1D thermo-fluid dynamic simulation code in order to cope with the different chemical and physical aspects due to the fuelling of a spark ignition engine with hydrogen rather than with conventional gasoline. In particular the combustion module, which is based on a quasi-dimensional approach, has been extended by introducing the possibility of predicting the burning rate of the combustion of a homogeneous mixture of hydrogen and air. A fractal approach was followed for the turbulent flame speed evaluation, while an extend database for laminar burning velocities was created applying a kinetic simulation code for one-dimensional laminar flames. The modelling of the whole intake and exhaust systems coupled to the engine has been addressed, considering port-injection fuel system, in which hydrogen has been injected at very low temperature (cryogenic conditions). The fundamental 1D fluid-dynamic equations are solved by means of second order finite difference schemes; the working fluid is considered as a mixture of ideal gases, with specific heats depending on the gas temperature and the mole fractions of species, whose correlations for each specie (including para-hydrogen) have been extended in the region of low temperature. A first validation of the enhanced model is shown in the paper, comparing the computed results with the experimental data of in-cylinder pressures, intake and exhaust instantaneous pressure histories at different locations and NO emissions discharged by the cylinder.

Author(s):  
Mehrnoosh Dashti ◽  
Ali Asghar Hamidi ◽  
Ali Asghar Mozafari

Using CNG as an additive for gasoline is a proper choice due to higher octane number of CNG enriched gasoline with respect to that of gasoline. As a result, it is possible to use gasoline with lower octane number in the engine. This would also mean the increase of compression ratio in SI engines resulting in higher performance and lower gasoline consumption. Over the years, the use of simulation codes to model the thermodynamic cycle of an internal combustion engine have developed tools for more efficient engine designs and fuel combustion. In this study, a thermodynamic cycle simulation of a conventional four-stroke spark-ignition engine has been developed. The model is used to study the engine performance parameters and emission characteristics of CNG/gasoline blend fuelled engine. A spark ignition engine cycle simulation based on the first law of thermodynamic has been developed by stepwise calculations for compression process, ignition delay time, combustion and expansion processes. The building blocks of the model are mass and energy conservation equations. Newton-Raphson method has been used to solve the equations numerically and there was no need to solve them analytically. In the quasi-dimensional combustion model, the cylinder is divided into two zones separated by a thin flame front. The flame front propagates spherically throughout the combustion chamber to the point that it contacts the cylinder wall and head. The model effectively describes the thermodynamic processes and chemical state of the working fluid via a closed system containing compression, combustion, and expansion processes. The model predicts the trends and tradeoffs the performance characteristics at various engine speeds. The variation of indicated power, ISFC and emissions are predicted by the model. Experimental data are also presented to indicate the validity of the model. The predicted results based on the model have shown reasonable agreement with the corresponding experimental data.


2021 ◽  
Vol 877 ◽  
pp. 141-146
Author(s):  
David Lie ◽  
Tjokorda Gde Tirta Nindhia ◽  
I Wayan Surata ◽  
Nengah Wirawan

The available of conventional fuels are fluctuating depend on distribution from the source production to consumer. The availability of biogas as renewable energy is increasing due to establishments of many organic wastes processing worldwide. The need of electricity to support daily life activity is a must, but the availability of electric source in remote area is limited especially for a farm that far away from commercial line distribution of electricity. This work is dedicated to solve this problem. The single cylinder 4 stroke spark ignition engine (83 cc) was designed to be able to be fuelled flexibly by using biogas or liquefied petroleum gas (LPG), or gasoline if sometime the biogas not available during initiation of the process or during maintenance of anaerobic digester. The engine is still can be run to provide electricity by using conventional fuel such as LPG or gasoline. The full consumption as well as emission of this flexible fuel engine was investigated. It is found that the fuel consumption is 9.97 L/mint for Biogas, 0.004 L/mint for gasoline and 2.24 L/mint for LPG. Surprisingly by using biogas the emission of carbon monoxide (CO) was down to almost zero (0.02 ppm), comparing gasoline 0.32 ppm, and LPG 0.4 ppm.


Author(s):  
Dinesh D. Adgulkar ◽  
N. V. Deshpande ◽  
S. B. Thombre ◽  
I. K. Chopde

By supporting hydrogen as an alternative fuel to the conventional fuel i.e. gasoline, new era of renewable and carbon neutral energy resources can be introduced. Hence, development of hydrogen fuelled internal combustion engine for improved power density and less emission of NOx has become today’s need and researchers are continuously extending their efforts in the improvement of hydrogen fuelled internal combustion engine. In this work, three dimensional CFD simulations were performed using CFD code (AVL FIRE) for premixed combustion of hydrogen. The simplified 3D geometry of engine with single valve i.e. inlet valve was considered for the simulation. Various combustion models for spark ignition for hydrogen i.e. Eddy Breakup model, Turbulent Flame Speed Closure Combustion Model, Coherent Flame model, Probability Density Function model were tested and validated with available simulation results. Results obtained in simulation indicate that the properties of hydrogen i.e. high flame speed, wide flammability limit, and high ignition temperature are among the main influencing factors for hydrogen combustion being different than that of gasoline. Different parameters i.e. spark advance angle (TDC to 40° before TDC in the step of 5°), rotational speed (1200 to 3000 rpm in the step of 300 rpm), equivalence ratio (0.5 to 1.2 in the step of 0.1), and compression ratio (8, 9 and 10) were used to simulate the combustion of hydrogen in spark ignition engine and to investigate their effects on the engine performance, which is in terms of pressure distribution, temperature distribution, species mass fraction, reaction progress variable and rate of heat release for complete cycle. The results of power output for hydrogen were also compared with that of gasoline. It has been observed that power output for hydrogen is almost 12–15% less than that of gasoline.


Author(s):  
Lorenzo Bartolucci ◽  
Stefano Cordiner ◽  
Vincenzo Mulone ◽  
Sundar R. Krishnan ◽  
Kalyan K. Srinivasan

Abstract Dual fuel diesel-methane low temperature combustion (LTC) has been investigated by various research groups, showing high potential for emissions reduction (especially oxides of nitrogen (NOx) and particulate matter (PM)) without adversely affecting fuel conversion efficiency in comparison with conventional diesel combustion. However, when operated at low load conditions, dual fuel LTC typically exhibit poor combustion efficiencies. This behavior is mainly due to low bulk gas temperatures under lean conditions, resulting in unacceptably high carbon monoxide (CO) and unburned hydrocarbon (UHC) emissions. A feasible and rather innovative solution may be to split the pilot injection of liquid fuel into two injection pulses, with the second pilot injection supporting the methane combustion once the process is initiated by the first one. In this work, diesel-methane dual fuel LTC is investigated numerically in a single-cylinder heavy-duty engine operating at 5 bar brake mean effective pressure (BMEP) at 85% and 75% percentage of energy substitution (PES) by methane (taken as a natural gas surrogate). A multidimensional model is first validated in comparison with experimental data obtained on the same single-cylinder engine for early single pilot diesel injection at 310 CAD and 500 bar rail pressure. With the single pilot injection case as baseline, the effects of multiple pilot injections and different rail pressures on combustion emissions are investigated, again showing good agreement with experimental data. Apparent heat release rate and cylinder pressure histories as well as combustion efficiency trends are correctly captured by the numerical model. Results prove that higher rail pressures yield reductions of HC and CO by 90% and 75%, respectively, at the expense of NOx emissions, which increase by ∼30% from baseline. Furthermore, it is shown that post-injection during the expansion stroke does not support the stable development of the combustion front as the combustion process is confined close to the diesel spray core.


Sign in / Sign up

Export Citation Format

Share Document