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Characterization of a C.I. engine operated using retrofit monogas fuelling concept

Osman, Shahrul Azmir (2014) Characterization of a C.I. engine operated using retrofit monogas fuelling concept. PhD thesis, Universiti Tun Hussein Onn Malaysia.

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Abstract

Recently, logistics and haulage companies are considering using CNG for their existing compression ignition (C.I.) engines. In an effort to address this challenge, a parametric study on a medium duty C.I. engine (naturally aspirated, 4.3L, 4-cylinder) operated using retrofitted Monogas concept is presented. Extensive simulation (GTPower software) and experimental works using an engine test bed had been carried out to characterize the Monogas engine. Generally, successful retrofitting demands modifications in combustion chamber profiles, compression ratio, fuelling, ignition timing, intake, and exhaust systems. The optimum re-entrance (RE) and toroidal radius (TR) ratio for retrofitting must be between 0.16 and 0.60, for a compression ratio (CR) of 11:1. From the various combustion chamber profile designs, the design with lower central projection and RE to TR ratio of 0.16 was considered as the optimum combustion chamber geometry profile. Using this design, the 4.3L C.I. engine was successfully converted and tested at steady state engine conditions and selected set-points driving cycle. The findings from the simulation showed that the tested Monogas engine exhibited lower brake torque (BT) and brake power (BP) in the range of 13% - 19%. It also produced lower CO2 (59%), CO (85%) and NOX (85%) emissions, with the penalties of HC emissions and brake specific fuel consumption (BSFC); increase of 85% and 13% respectively. Comparisons with experimental works using C.I. engine had concluded that the Monogas engine was operating with high BSFC with an improved volumetric efficiency ( ) in the range of 40% to 58%. It also released lower CO (68%) and HC (48%) emissions, and high CO2 emissions, indicating high combustion efficiency. However, NOX emissions were higher in both experimental settings, whereas HC emissions were observed to be higher during the driving cycle set-point tests. Therefore, the methodology developed offers a successful C.I. engine converted to Monogas engine system via retrofit technology and an opening for future development and characterization into comprehensive support for implementation of energy efficient and environmental friendly vehicles.

Item Type: Thesis (PhD)
Subjects: T Technology > TJ Mechanical engineering and machinery > TJ751-805 Miscellaneous motors and engines
Depositing User: Normajihan Abd. Rahman
Date Deposited: 30 May 2016 07:22
Last Modified: 30 May 2016 07:22
URI: http://eprints.uthm.edu.my/id/eprint/8049
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