A quasi-one-dimensional model for an outwardly opening poppet-type direct gas injector for internal combustion engines

2019 ◽  
Vol 21 (8) ◽  
pp. 1493-1519
Author(s):  
Abhishek Y Deshmukh ◽  
Carsten Giefer ◽  
Dominik Goeb ◽  
Maziar Khosravi ◽  
David van Bebber ◽  
...  
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Flow Model ◽  
Direct Injection ◽  
Source Model ◽  
Gas Jet ◽  
Nozzle Flow ◽  
Combustion Engines ◽  
Compressed Natural Gas ◽  
One Dimensional

Direct injection of compressed natural gas in internal combustion engines is a promising technology to achieve high indicated thermal efficiency and, at the same time, reduce harmful exhaust gas emissions using relatively low-cost fuel. However, the design and analysis of direct injection–compressed natural gas systems are challenging due to small injector geometries and high-speed gas flows including shocks and discontinuities. The injector design typically involves either a multi-hole configuration with inwardly opening needle or an outwardly opening poppet-type valve with small geometries, which make accessing the near-nozzle-flow field difficult in experiments. Therefore, predictive simulations can be helpful in the design and development processes. Simulations of the gas injection process are, however, computationally very expensive, as gas passages of the order of micrometers combined with a high Mach number compressible gas flow result in very small simulation time steps of the order of nanoseconds, increasing the overall computational wall time. With substantial differences between in-nozzle and in-cylinder length and velocity scales, simultaneous simulation of both regions becomes computationally expensive. Therefore, in this work, a quasi-one-dimensional nozzle-flow model for an outwardly opening poppet-type injector is developed. The model is validated by comparison with high-fidelity large-eddy simulation results for different nozzle pressure ratios. The quasi-one-dimensional nozzle-flow model is dynamically coupled to a three-dimensional flow solver through source terms in the governing equations, named as dynamically coupled source model. The dynamically coupled source model is then applied to a temporal gas jet evolution case and a cold flow engine case. The results show that the dynamically coupled source model can reasonably predict the gas jet behavior in both cases. All simulations using the new model led to reductions of computational wall time by a factor of 5 or higher.

A Numerical Investigation of Combustion Chamber Geometry Effects on Natural Gas Direct Injection Properties in a SI Engine With Centrally Mounted Multi-Hole Injector

2012 ◽  
Author(s):  
Bijan Yadollahi ◽  
Masoud Boroomand
Keyword(s):  
Numerical Model ◽  
Natural Gas ◽  
Flow Field ◽  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Gasoline Engine ◽  
Direct Injection ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Validity Of Results

Due to the vast resources of natural gas (NG), it has emerged as an alternative fuel for SI internal combustion engines in recent years. The need to have better fuel economy and less emission especially that of greenhouse gases has resulted in development of NG fueled engines. Direct injection of natural gas into the cylinder of SI internal combustion engines has shown great potential for improvement of performance and reduction of engine emissions especially CO2 and PM. Direct injection of NG into the cylinder of SI engines is rather new thus the flow field phenomena and suitable configuration of injector and combustion chamber geometry has not been investigated completely. In this study a numerical model has been developed in AVL FIRE software to perform investigation of direct natural gas injection into the cylinder of spark ignition internal combustion engines. In this regard, two main parts have been taken into consideration aiming to convert an MPFI gasoline engine to direct injection NG engine. In the first part of study multidimensional numerical simulation of transient injection process, mixing and flow field have been performed via different validation cases in order to assure the numerical model validity of results. Adaption of such a modeling was found to be a challenging task because of required computational effort and numerical instabilities. In all cases present results were found to have excellent agreement with experimental and numerical results from literature. In the second part, using the moving mesh capability, the validated model has been applied to methane injection into the cylinder of a direct injection engine. Five different piston head shapes have been taken into consideration in investigations. An inwardly opening multi-hole injector has been adapted to all cases. The injector location has been set to be centrally mounted. The effects of combustion chamber geometry have been studied on mixing of air-fuel inside cylinder via quantitative and qualitative representation of results. Based on the results, suitable geometrical configuration for a NG DI engine has been discussed.

scholarly journals Lean-burn CNG engine with ignition chamber: from the idea to a running engine

2019 ◽  
Vol 176 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Michael WEIßNER ◽  
Frank BEGER ◽  
Martin SCHÜTTENHELM ◽  
Gunesh TALLU
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
State Of The Art ◽  
Combustion Engines ◽  
Lean Burn ◽  
Compressed Natural Gas ◽  
Emission Regulations ◽  
Cng Engine ◽  
Funded Project ◽  
The Eu

Current and further developing CO2- and emission regulations worldwide and the competition to full electric mobility deliver a chal-lenge for internal combustion engines in general. A state of the art solution is the use of natural gas mainly contending methane to reduce CO2 significantly and to offer lowest emission levels. The EU-funded project GasOn developed engine concepts to fully exploit the advantages of CNG. This article describes the development of an innovative, monovalent engine dedicated to Compressed Natural Gas (CNG) and characterised by the lean burn concept and the innovative pre-chamber combustion.

scholarly journals Hydrogen enriched compressed natural gas (HCNG): A futuristic fuel for internal combustion engines

2011 ◽  
Vol 15 (4) ◽  
pp. 1145-1154 ◽  
Author(s):  
Kasianantham Nanthagopal ◽  
Rayapati Subbarao ◽  
Thangavelu Elango ◽  
Ponnusamy Baskar ◽  
Kandasamy Annamalai
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Compressed Natural Gas

scholarly journals Performance, Efficiency and Emissions Evaluation of Gasoline Port-Fuel Injection, Natural Gas Direct Injection and Blended Operation

2016 ◽  
Author(s):  
Michael Pamminger ◽  
Thomas Wallner ◽  
James Sevik ◽  
Riccardo Scarcelli ◽  
Carrie Hall ◽  
...  
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Process ◽  
Internal Combustion ◽  
Intake Port ◽  
Combustion Engines ◽  
Part Load ◽  
Port Fuel Injection

The need to further reduce fuel consumption and decrease the output of emissions — in order to be within future emissions legislation — is still an ongoing effort for the development of internal combustion engines. Natural gas is a fossil fuel which is comprised mostly of methane and makes it very attractive for use in internal combustion engines because of its higher knock resistance and higher molar hydrogen-to-carbon ratio compared to gasoline. The current paper compares the combustion and emissions behavior of the test engine being operated on either a representative U.S. market gasoline or natural gas. Moreover, specific in-cylinder blend ratios with gasoline and natural gas were also investigated at part-load and wide open throttle conditions. The dilution tolerance for part-load operation was investigated by adding cooled exhaust gas recirculation. The engine used for these investigations was a single cylinder research engine for light duty application which is equipped with two separate fuel systems. Gasoline was injected into the intake port; natural gas was injected directly into the cylinder to overcome the power density loss usually connected with port fuel injection of natural gas. Injecting natural gas directly into the cylinder reduced both ignition delay and combustion duration of the combustion process compared to the injection of gasoline into the intake port. Injecting natural gas and gasoline simultaneously resulted in a higher dilution tolerance compared to operation on one of the fuels alone. Significantly higher net indicated mean effective pressure and indicated thermal efficiency were achieved when natural gas was directly injected after intake valve closing at wide open throttle, compared to an injection while the intake valves were still open. In general it was shown that the blend ratio and the start of injection need to be varied depending on load and dilution level in order to operate the engine with the highest efficiency or highest load.

scholarly journals Hydrogen-Methane Blend Fuelling of a Heavy-Duty, Direct-Injection Engine

2007 ◽  
Author(s):  
G. P. McTaggart-Cowan ◽  
S. R. Munshi ◽  
S. N. Rogak ◽  
P. G. Hill ◽  
W. K. Bushe
Keyword(s):  
Natural Gas ◽  
Power Plants ◽  
Internal Combustion Engines ◽  
Direct Injection ◽  
Ghg Emissions ◽  
Combustion Stability ◽  
Combustion Engines ◽  
Heavy Duty ◽  
Steam Methane ◽  
Transportation Applications

Combining hydrogen with natural gas as a fuel for internal combustion engines provides an early opportunity to introduce hydrogen into transportation applications. This study investigates the effects of fuelling a heavy-duty engine with a mixture of hydrogen and natural gas injected directly into the combustion chamber. The combustion system is unmodified from that developed for natural gas fuelling. The results demonstrate that hydrogen can have a significant beneficial effect in reducing emissions without affecting efficiency or requiring significant engine modifications. Combustion stability is enhanced through the higher reactivity of the hydrogen, resulting in reduced emissions of unburned methane. The fuel’s lower carbon-energy ratio also reduces CO2 emissions. These results combine to significantly reduce tailpipe greenhouse gas (GHG) emissions. However, the effect on net GHG’s, including both tailpipe and fuel-production emissions, depends on the source of the hydrogen. Cleaner sources, such as electrolysis based on renewables and hydro-electric power, generate a significant net reduction in GHG emissions. Hydrogen generated by steam-methane reforming is essentially GHG neutral, while electrolysis using electricity from fossil-fuel power plants significantly increases net GHG emissions compared to conventional natural gas fuelling.

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