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Direct Injection of CNG on High Compression Ratio Spark Ignition Engine: Numerical and Experimental Investigation
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 12, 2011 by SAE International in United States
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CNG is one of the most promising alternate fuels for passenger car applications. CNG is affordable, is available worldwide and has good intrinsic properties including high knock resistance and low carbon content.
Usually, CNG engines are developed by integrating CNG injectors in the intake manifold of a baseline gasoline engine, thereby remaining gasoline compliant. However, this does not lead to a bi-fuel engine but instead to a compromised solution for both Gasoline and CNG operation.
The aim of the study was to evaluate the potential of a direct injection spark ignition engine derived from a diesel engine core and dedicated to CNG combustion. The main modification was the new design of the cylinder head and the piston crown to optimize the combustion velocity thanks to a high tumble level and good mixing.
This work was done through computations. First, a 3D model was developed for the CFD simulation of CNG direct injection. Numerical tests were carried out on the injection test bench configuration in order to achieve good correlations between calculations and experiments. Once validated, the model was implemented in the numerical setup of the engine and different designs of the combustion chamber were computed to compare mixing level, turbulent energy level, trapped mass and IMEP for homogenous stoichiometric operation. The best design was then manufactured and tested on a single-cylinder research engine.
Comparing test bench results of CNG port injection and CNG direct injection configurations showed the potential of direct injection: - later injection timings lead to higher volumetric efficiency, - later spark ignition timings lead to higher burning speed for a better indicated fuel consumption.
Finally, the test bench results were extrapolated to construct a numerical model of a multi-cylinder engine as well as a vehicle. NEDC cycle simulations using a DI CNG-engine-powered Light-Duty Vehicle have shown a 27% reduction of CO₂ emissions compared to the same vehicle equipped with a diesel engine, making DI CNG engines a credible alternative for the European market.
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|Technical Paper||Conversion of a Multivalve Gasoline Engine to Run on CNG|
CitationDouailler, B., Ravet, F., Delpech, V., Soleri, D. et al., "Direct Injection of CNG on High Compression Ratio Spark Ignition Engine: Numerical and Experimental Investigation," SAE Technical Paper 2011-01-0923, 2011, https://doi.org/10.4271/2011-01-0923.
- Cho, H.M., He, B.Q., “Spark ignition natural gas engines - a review”, Energy Conversion and Management Vol. 48: 608-618, 2007, doi: 10.1016/j.enconman.2006.05.023.
- Tilagone, R., Venturi, S., Monnier, G., “Natural Gas - an environmentally friendly fuel for urban vehicles: the SMART demonstrator approach”, Oil & Gas Science and Technology Vol. 61(1): 155-164, 2006, doi: 10.2516/ogst:2006010x.
- Wayne, W., Clark, N., and Atkinson, C., “A Parametric Study of Knock Control Strategies for a Bi-Fuel Engine,” SAE Technical Paper 980895, 1998, doi: 10.4271/980895.
- Taniguchi, S., Tsukasaki, Y., Yasuda, A., “Study of compressed natural gas injection engine,” FISITA paper F2006P089, 2006.
- Baratta, M., Catania, A.E., Spessa, E., Herrmann, L., and Roessler, K., “Multi-Dimensional Modeling of Direct Natural Gas Injection and Mixture Formation in a Stratified-Charge SI Engine with Centrally Mounted Injector”, SAE Int. J. Engines 1(1):607-626, 2008, doi:10.4271/2008-01-0975.
- Bohbot, J., Gillet, N., Benkenida, A., “IFP-C3D: an Unstructured Parallel Solver for Reactive Compressible Gas Flow with Spray”, Oil & Gas Science and Technology Vol. 64: 309-336, 2009, doi: 10.2516/ogst/2009016.
- Colin, O., Benkenida, A., “The 3-Zones Extended Coherent Flame Model (ECFM3Z) for computing premixed diffusion combustion”, Oil & Gas Science and Technology Vol. 59 (6): 593-609, 2004, doi: 10.2516/ogst:2004043.
- Colin, O., Pirès da Cruz, A., Jay, S., “Detailed chemistry-based auto-ignition model including low temperature phenomena applied to 3-D engine calculations”, Proceedings of the Combustion Institute Vol. 30 (2): 2649-2656, 2005, doi: 10.1016/j.proci.2004.08.058.
- Duclos, J.-M., Colin, O., “Arc and Kernel Tracking Ignition Model for 3D Spark Ignition Engine Calculations”, 5th Int. Symp. on Diagnostics and Modeling of Combustion in Internal Combustion Engines, COMODIA 2001, Nagoya, Japan.
- Knop, V., Benkenida, A., Jay, S., Colin, O., “Modelling of combustion and nitrogen oxide formation in hydrogen-fuelled internal combustion engines within a 3D CFD code”, International Journal of Hydrogen Energy Vol. 33 (19): 5083-5097, 2008, doi: 10.1016/j.ijhydene.2008.06.027.
- Kim, G.H., Kirkpatrick, A., and Mitchell, C., “Computational Modeling of Natural Gas Injection in a Large Bore Engine”, ASME Trans., Journal of Engineering for Gas Turbines and Power Vol. 126 : 656-664, 2004, doi: 10.1115/1.1762906.
- Gülder, O.L. 1990. “Turbulence premixed flame propagation models for different combustion regimes”, 23rd Symp. (Int.) on Combustion, The Combustion Institute, pp. 743-750, doi:10.1016/S0082-0784(06)80325-5.