Analysis of Compressed Natural Gas Burn Rate and Flame Propagation on a Sub-Compact Vehicle Engine
In terms of sub-compact cars using alternative fuels, the vehicle characteristics are governed by the engine operation. The main focus of this paper was to evaluate a subcompact car engine on its performance and burn rate of gasoline and compressed natural gas (CNG) . A bi-fuel sequential system...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Universiti Malaysia Pahang
2015
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| Subjects: | |
| Online Access: | http://umpir.ump.edu.my/id/eprint/10965/ http://umpir.ump.edu.my/id/eprint/10965/ http://umpir.ump.edu.my/id/eprint/10965/ http://umpir.ump.edu.my/id/eprint/10965/1/Analysis%20of%20Compressed%20Natural%20Gas%20Burn%20Rate%20and%20Flame%20Propagation%20on%20a%20Sub-Compact%20Vehicle%20Engine.pdf |
| Summary: | In terms of sub-compact cars using alternative fuels, the vehicle characteristics are
governed by the engine operation. The main focus of this paper was to evaluate a subcompact
car engine on its performance and burn rate of gasoline and compressed natural
gas (CNG) . A bi-fuel sequential system was used for this evaluation. Measurements of
engine speed, torque and fuel were done on an eddy current dynamometer, while
measurements of in-cylinder pressure, crank angle and spark were analyzed from results
taken by a data acquisition system. The emissions readings were also compared using an
emission analyzer. The results were analyzed for burn rate based on the first law of
thermodynamics. A 3-dimensional computational fluid dynamics (CFD) model was
done to estimate the flame speed. The comparison shows an average drop of 18.6% for
the power, 7% for brake specific fuel consumption (BSFC) and the efficiency loss was
17.3%. Pressure analysis shows peak pressure dropped by 16%. The burn rate shows
why CNG had a slower burning speed on the small engine. CFD predicted the flame
propagation speed at 8.45 m/s. The engine speed of 4000 rpm at maximum brake torque
produced the results nearest to those for gasoline. In conclusion, volumetric losses and
CFD errors slightly reduce the accuracy of the results, but nevertheless an 8.45 m/s
flame speed was estimated. |
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