Nik Rosli Abdullah

The Effect of Oil Supply Pressure on the Circumferential Pressure Profile in Hydrodynamic Journal Bearing

In hydrodynamic lubrication, the pressure condition of the fluid is critical to ensure good performance of the lubricated machine elements such as journal bearings. In the present study, an experimental work was conducted to determine the effect of oil supply pressure on pressure profile around the circumference of a journal bearing. A journal diameter of 100mm with a ½ length-to-diameter ratio was used. The oil supply pressure was set at three different values (0.3, 0.5, 0.7 Mpa) and the circumferential pressure results for 400, 600 and 800 RPM at different radial loads were obtained. It was observed that the maximum pressure values were affected by changes in oil supply pressure.

Effects of pilot injection timing and EGR on a modern V6 common rail direct injection diesel engine

Nitric oxide and smoke emissions in diesel engine can be controlled by optimising the air/fuel mixture. Early injection produces premixed charge resulted in simultaneous NOx and smoke emissions reduction. However, there could be an increase in hydrocarbons and CO emissions due to fuel impinged to the cylinder wall. The focus of the present work is to investigate the effects of a variation of pilot injection timing with EGR to NOx and smoke level on a modern V6 common rail direct injection. This study is carried out at two different engine load conditions of 30 Nm and 55 Nm, at constant engine speed of 2000 rpm. The results show that the early pilot injection timing contributed to the lower smoke level and higher NOx emissions. The higher level of NOx is due to higher combustion temperatures resulting from the complete combustion. Meanwhile, the lower smoke level is due to complete fuel combustion and soot oxidation. The early pilot injection timing produces an intermediate main ignition delay which also contributed to complete combustion. The formation of smoke is higher at a high engine load compared with low engine load due to the higher amount of fuel being injected.

Application of Response Surface Methodology to Predict Oil-Film Friction in Journal Bearing

Oil-film friction response is one of the key parameters that describe the operating conditions in hydrodynamic lubrication regimes. In the present paper, response surface methodology (RSM) with Box-Behnken experiment Design technique (BBD) has been utilized to predict and evaluate the effects of the three-level-three-independent variables on the oil-film friction. The design independent variables including rotational speed, load and oil-feed pressure were used to develop an empirical model for the oil-film friction in hydrodynamic plain journal bearing. A salient feature of this study is to investigate the interaction between the main three factors and provide a profound understanding on the significance of each factor. The analysis of variance (ANOVA) of the regression model and comparison of predicted and observed response values have showed good correspondence, implying that empirical model derived from response surface approach can predict the response adequately.

A multiphase Eulerian-Eulerian CFD simulation of fluidized bed gasification using Malaysian low-rank coal-merit pila

A multiphase Eulerian- eulerian model integrating the kinetic theory of granular particle (KTGF) was used to simulate the gasification of Malaysian low- rank coal (LRC), Merit- Pila inside a bubbling fluidised bed (BFB) gasifier. The model used includes the bubbling phenomenon and gasificationprocess that occurs inside a BFB gasifier. The gasification process simulated includes drying, heterogeneous reactions of char combustion, devolatilization, water- gas shift reaction, Boudourd reactionand gas phase homogenous reactions. The results from this model are compared to the results of Merit-Pila coal gasification, from which experimental data is available. Comparison of the pressure profile shows good agreement with experimental results. The temperature distribution shows that the maximum temperature is around 1100K which also shows good agreement with experimental values which is 1087K. Besides that, three out of six species mass fraction which is N2, H2 and CH4 produced similar values with experimental values. This shows the simulation conducted was capable to predict the gasification process of Low- rank coal, namely Merit-Pila.

One-Dimensional Simulation of the Combustion Process in an Engine Cylinder with Ethanol

The diesel engine is one of the most important engines for road vehicles. The engine nowadays operates with different kinds of alternative fuels, such as natural gas and biofuel. The aim of this article is to study the combustion process that occurs in an engine cylinder of a diesel engine when using biofuel. The one-dimensional numerical analysis using GT-Power software is used to simulate the commercial four-cylinder diesel engine. The engine operated at high engine load and speed. The ethanol fuel used in the simulation is derived from the conventional ethanol fuel properties. The analysis of simulations includes the cylinder pressure, combustion temperature and rate of heat release. The simulation results show that in-cylinder pressure and temperature for ethanol is higher than for diesel at any engine speed. However, the mass fraction of ethanol burned is similar to that of diesel. MFB only affects the engine speed.

Combustion Characteristic of a Diesel Engine Operating with Methanol as Alternative Fuel

Modelling the compression ignition engine mostly depends on fuel characteristics. The proses involve a model of the real system and carry out experiment as a mean of comparison to understand the behaviour of the system. The diesel engine nowadays operated with different kind of alternative fuels such as natural gas and biofuel. The aim of this article is to study the combustion characteristic occurred in an engine cylinder of a diesel engine when using biofuel. The one-dimensional numerical analysis using GT-Power software is used to simulate the diesel engine. The engine operated at full engine load and difference speed. The methanol fuel used in the simulation is derived from the conventional methanol fuel properties. The analysis of simulations includes the cylinder pressure, combustion temperature and rate of heat release. The simulation result shows that in-cylinder pressure for methanol is slightly higher than diesel fuel in any speed of the engine. It also found that the combustion characteristic on methanol temperature is higher at all crank angle degree of diesel fuel. Mass fraction burns of methanol are much lower than diesel fuel, but burns faster than diesel fuel.

Investigation of the Effects of Inlet System Configuration on the Airflow Characteristics

The effort towards the development of an engine that is efficient and green has become one of the biggest efforts of the major part of the automotive industry. The contribution of air quality to the engine plays an important role to increase power while minimizing the exhaust emission. The main purpose of this article is to investigate the characteristic of the air intake system of a naturally aspirated engine on a steady flow bench. The experiment was conducted using an industrial flow bench apparatus where the pressure different test pressures can be set and, at every test pressure, the valve is lifted at an increment of 1mm until the maximum possible valve lift where the flow rate is obtained in terms of cubic foot per minute or CFM. The experiment process was then repeated at different configuration. The experimental result shows that the flow rate increases with each valve lift in a linear pattern until at a certain point where the value becomes constant. The result also indicated that the flow rate increases as the different pressure increases.

Performance and Emissions of Jatropha-Palm Blended Biodiesel

This paper deals with performances and emissions of Jatropha-Palm blended biodiesel as fuel for 4-stroke single vertical cylinder diesel engine. Five fuel samples were tested; i) Diesel fuel supplied by Petronas (PDF); ii) 5% of blended Jatropha-Palm biodiesel and 95% Diesel fuel (B5JPB); iii) 10% of blended Jatropha-Palm biodiesel and 90% Diesel fuel (B10JPB); iv) 15% of blended Jatropha-Palm biodiesel and 85% Diesel fuel (B15JPB); and v) 20% of blended Jatropha-Palm biodiesel and 80% Diesel fuel (B20JPB). Engine performances (specific fuel consumption, brake thermal efficiency) and emissions (exhaust gas temperature and Nox emission) were analyzed and have been discussed in this study. All tests were carried out at varied load conditions which were 0.13, 0.15, 0.17, 0.19 and 0.21 kW. The results revealed that B10JPB blended showed better engine performances compared to its other blends and comparable performances compared to PDF. Comparable Nox emitted of all Jatropha-Palm fuel blended biodiesel fuel sample has been demonstrated to those PDF.

Investigation of Intake Flow Rate and Swirl Motion of Sl Engine

In the process of producing an optimized air intake system design, detailed understanding of the airflow motion is required. To reach such understanding, this paper aims to investigate the flow rate and swirl motion of an engines inlet system at different pressures and different conditions. Using a commercial steady flow bench and a swirl meter, the different parameters, the flow rate and swirl coefficient, is obtained at different valve lifts. The inlet system will then be tested in different pressures and at different engine configurations. Since the tested inlet system has two valves in its intake port, both valves are tested separately as well as tested together. It is found that the flow rate pattern mirrors the swirl pattern where the value increases as the valve lift increases but decreases and levels after a certain valve lift. Increase in pressure from 5kPa to 10kPa exhibits a 43% increase in flow rate and 90% increase in swirl coefficient and by removing the manifold, the flow rate only increase by 4% but the swirl coefficient changes by 30%. Theses findings show the main factors that affects the intake process and the results will be used as a baseline to improve the intake system.

Potential Utilization of Biodiesel as Alternative Fuel for Compression Ignition Engine in Malaysia

Global total petroleum deficit and environmental concern on the emissions issues concerning pure diesel had started a technological race in producing alternative sources of energy which includes renewable fuel. Among the developed renewable fuels is the biodiesel which is a type of fuel derived from various sources of vegetable plants and waste fuels. Various biodiesels have been engineered to beat par to or even perhaps, a leap better in term of performance topure diesel. In short,biodiesel has shown a promising sign as the best candidate in overcoming total dependent on petroleum-derived fuel.This paper gives review on various tests and experiments conducted on biodiesel in order to highlight the potentials preserved by the fuel and to further endorse for a more mass usage of biodiesel and simultaneously for Malaysia to be a potential global producer of biodiesel fuels in the near future.