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https://ptsldigital.ukm.my/jspui/handle/123456789/487112Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | Shahrir Abdullah, Prof. Ir. Dr. | |
| dc.contributor.author | Saad Mohsen Saad Aljamali (P55877) | |
| dc.date.accessioned | 2023-10-11T02:29:00Z | - |
| dc.date.available | 2023-10-11T02:29:00Z | - |
| dc.date.issued | 2020-03-17 | |
| dc.identifier.other | ukmvital:123076 | |
| dc.identifier.uri | https://ptsldigital.ukm.my/jspui/handle/123456789/487112 | - |
| dc.description | In recent years, natural-gas has been considered as an alternative clean fuel for spark ignition (SI) engines because of its relatively higher octane number. Lean burning of natural gas, which contains mostly methane, in SI engines has been potential to improve thermal efficiency and reduce emissions compared to gasoline. Due to its high research, octane number (RON) which is higher than 120, natural gas allows combustion at a higher compression ratio without knocking. It also offers much lower CO2 gas emissions compared with other hydrocarbon fuels as a result of its higher hydrogen to the carbon ratio. Because of CNG properties, a new compressed natural-gas direct injection (CNGDI) engine has been design, installed in UKM, and used as the main test apparatus for this study. In this study, the first test was carried out using the CNGDI engine with homogenous charge combustion, followed by the second test using the same engine with stratified charge combustion to compare the performance, emissions and pressure combustion of both combustion. All the test outputs were analysed and investigated using the KRONOS4 software. An engine control system and portable exhaust gas analyser were used to control the engine operations and to record the engine performance and emission data. In all the tests, performance, emission and combustion pressure were assessed under various engine load and engine speed until 4000 RPM. In addition, the fuel-injection timings were investigated in an effort to optimize the performance and emissions. For homogenous charge combustion, the injection timing is set at early of compression stroke. For stratified charge operation combustion, natural gas is injected at the late of compression stroke. The injection point starts between 200 ̊ to 150 ̊ BTDC depends on engine speeds so it can start at the end of intake stroke or early of compression stroke. In summary, the results showed that the power and torque are higher in the CNGDI engine with homogenous and stratified combustion. In both CNGDI homogenous and stratified combustion, the best injection is observed when the end of injection 120 before top-dead centre (BTDC). However, the power and torque are more in CNGDI stratified combustion, specifically at low speeds compare to CNGDI homogenous combustion. In addition, the brake mean effective pressure (BMEP), volumetric efficiency, and lambda are more at stratified combustion. Brake specific fuel consumption (BSFC) is less in stratified combustion at all engine speeds. By comparing the result from both homogenous and stratified combustion, there is slight increasing in the stratified combustion for the emissions of CO, CO2, and NO. From this study, the pressure combustion is investigated versus engine displacement and crankshaft angle. All peak pressures occur after top-dead centre (ATDC) for both homogenous and stratified combustion. In addition, all the peak values of pressure by the stratified combustion are about 20% lower than the one produced by the homogenous combustion. The high peak pressure will affect the engine and reduce the engine life so the stratified combustion is better than homogenous.,Ph.D. | |
| dc.language.iso | eng | |
| dc.publisher | UKM, Bangi | |
| dc.relation | Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina | |
| dc.rights | UKM | |
| dc.subject | Universiti Kebangsaan Malaysia -- Dissertations | |
| dc.subject | Dissertations, Academic -- Malaysia | |
| dc.subject | Fuel | |
| dc.subject | Natural gas | |
| dc.subject | Engines | |
| dc.title | Performance analysis of the CNG-DI engine under homogenous and stratified mixture | |
| dc.type | Theses | |
| dc.format.pages | 102 | |
| dc.identifier.callno | TP318.J336 2020 3 tesis | |
| dc.identifier.barcode | 005667(2021)(PL) | |
| Appears in Collections: | Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina | |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| ukmvital_123076+SOURCE1+SOURCE1.0.PDF Restricted Access | 3.43 MB | Adobe PDF |  View/Open |
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