Shahrul Azmir Osman

Performance and Emissions Characteristics of Diesel Engine Fuelled by Biodiesel Derived from Palm Oil

Bio fuels based on vegetable oils offer the advantage being a sustainable, annually renewable source of automobile fuel. Despite years of improvement attempts, the key issue in using vegetable oil-based fuels is oxidation stability, stoichiometric point, bio-fuel composition, antioxidants on the degradation and much oxygen with comparing to diesel gas oil. Thus, the improvement of emissions exhausted from diesel engines fueled by biodiesel derived from palm oil is urgently required to meet the future stringent emission regulations. Purpose of this study is to explore how significant the effects of palm oil blending ratio on combustion process that strongly affects the vehicles performance and exhaust emissions. The engine speed was varied from 15003000 rpm, load test condition varied by Dynapack chassis dynamometer from 050% and palm oil blending ratio from 515vol% (B5B15). Increased blends of biodiesel ratio is found to enhance the combustion process, resulting in decreased the HC emissions with nearly equal of engine performance. The improvement of combustion process is expected to be strongly influenced by oxygenated fuel in biodiesel content.

Predicting the Performance and Emissions Characteristics of a Medium Duty Engine Retrofitted with Compressed Natural Gas System Using 1-Dimensional Software

The rise of crude oil price and the implications of exhaust emissions to the environment from combustion application call for a new reliable alternative fuel. A potential alternative fuel for compression ignition (C.I.) engine is the compressed natural gas (CNG). For C.I. engines to operate using CNG, or to be converted as a retrofitted CNG engine, further modifications are required. Previous works reported loss in brake power (BP) and increase in hydrocarbon (HC) emission for C.I. engine retrofitted with CNG fuelling. Verification of performance characteristics for CNG retrofitted engine through experimental analysis requires high cost and is very time consuming. Thus, a 1-Dimensional simulation software, GT-Power, was introduced in this study to reduce the experimental process and setup. A 4-cylinder medium duty C.I. engine (DE) and CNG retrofitted engine (RE) GT-Power models were used in this simulation work over various operational conditions: low, medium and high load conditions. As compared with DE model, results from RE model showed that RE model achieved an average 4.9% improvement for brake specific fuel consumption (BSFC) and loss in BP by 37.3%. For nitrogen oxides (NOX) and carbon dioxides (CO2) RE model predicted reduction of 48.1% (engine mode 1-9) and 33.4% (all engine modes), respectively. Moreover, RE produced 72.4% more carbon monoxide (CO) and 90.3% more HC emission.

Mono-gas fuelled engine performance and emissions simulation using GT-Power

The scarcity of oil resources and the rise of crude oil price had driven the whole world to seek for an alternative fuel for automotive industry. One of the prospective alternative fuels for compression ignition (C.I.) engine is compressed natural gas (CNG). In order to operate CNG in a C.I. engine as mono-gas engine (RE), several modifications are required. The modifications that involves are compression ratio, fuel injection type, addition of spark plug and fuel itself. So as to reduce the time in preparing the experimental test bed and high cost analytical study a 1-dimensional simulation software GT-Power was introduce. The GT-Power simulation model for a 4 cylinder medium duty C.I. engine (DE) and RE has been built to study the effects of conversion process to the performance and emissions of the engine at various operational conditions: low, medium and high load conditions. As compared with DE model, results from RE model showed loss in brake power (BP) and brake thermal efficiency (BTE) by 37.3% and 19% respectively. Meanwhile, for brake specific air consumption (BSAC) RE predicted to undergo an average of 19412.6 g/kW-h and increment in volumetric efficiency by percentage of difference 22%. In other side, oxides of nitrogen (NOx) RE engine model predicted reduction of 48.1% (engine mode 1-9) and increased in hydrocarbons (HC) by 90.3.

Performance and emission characteristics of direct injection C.I engine retrofitted with mono-CNG system

Diesel engines are widely used in logistics and haulage as vehicular prime movers. In the mechanized and fast-moving forward world of today, the consumption of petroleum products has become an important yardstick of a country’s prosperity. This ever-increasing consumption has led the world to face the twin challenge of energy shortage and environmental deterioration. Natural gas has been one of the highly considered alternative fuels for both spark ignition (S.I) and compressed ignition (C.I.) engines. The advantages and benefits of CNG have made it the preferred choice as alternative fuel in the transportation sector. This present study focused on the effects of retrofitted direct injection C.I. engine with mono-CNG system to its performance and exhaust emissions. The engine speed was varied from 850 rpm to 2500 rpm, with load test conditions of 0Nm, 27.12Nm and 53.23Nm, using an engine dynamometer. Results indicated that CNG has the potential to provide better fuel consumption compared to diesel fuel. Meanwhile, the characteristics of exhaust gas emissions such as smoke opacity and CO2 gave promising results compared to CO, HC and NOX, for diesel combustion.

A Review on Knock Phenomena in CNG-Diesel Dual Fuel System

The compressed natural gas (CNG) – diesel dual fuel engine is discussed through their basic operation and its characteristic. The main problem of running a diesel engine on dual fuel mode with CNG as main fuel is addressed. A brief review of knock phenomena which is widely associated with a dual fuel engine is also covered. Methods to suppress onset knock were suggested.

Optimum Combustion Chamber Geometry for a Compression Ignition Engine Retrofitted to Run Using Compressed Natural Gas (CNG)

The use of natural gas as an alternative fuels are motivated from the impact in deteriorating quality of air and the energy shortage from petroleum products. Through retrofitting, CI engine runs on CNG, will be able to reduce the negative impact mainly on the use of petroleum products. However, this required the modification of the combustion chamber geometry by reducing the compression ratio to value that suits combustion of CNG. In this present studies, four different shapes and geometries of combustion chamber were designed and simulate using CFD package powered by Ansys workbench, where k-ε turbulence model was used to predict the flow in the combustion chamber. The results of turbulence kinetic energy, velocity vectors and streamline are presented. The enhancement of air-fuel mixing inside the engine cylinder can be observed, where the design with re-entrance and lower center projection provide better results compared to other combustion geometries designs.

One dimensional modeling of a diesel-CNG dual fuel engine

Some of the previous studies have shown that the use of compressed natural gas (CNG) in diesel engines potentially produce engine performance improvement and exhaust gas emission reduction, especially nitrogen oxides, unburned hydrocarbons, and carbon dioxide. On the other hand, there are other researchers who claimed that the use of CNG increases exhaust gas emissions, particularly nitrogen oxides. In this study, a one-dimensional model of a diesel-CNG dual fuel engine was made based on a 4-cylinder 2.5L common rail direct injection diesel engine. The software used is GT-Power, and it was used to analyze the engine performance and exhaust gas emissions of several diesel-CNG dual fuel blend ratios, i.e. 100:0, 90:10, 80:20, 70:30, 60:40 and 50:50. The effect of 100%, 75%, 50% engine loads on the exhaust gas emissions were also studied. The result shows that all diesel-CNG fuel blends produces higher brake torque and brake power at engine speed of 2000-3000 rpm compared with 100% diesel. The 50:50 diesel-C...

Application of injector-volume ratio values in the development of a fuel injection controller

The primary function of an electronic control unit (ECU) of an engine is to calculate the amount of fuel to be delivered into the combustion chamber. The injection duration and duty cycle of the injector will be based on several sensors whose signals the ECU will process to ensure the best engine running condition. However, to study new injection and combustion strategies, where such operation is unavailable in standard ECU, a custom-built fuel injection control system need to be made. This paper describes the development of a fuel injector signal controller, which is being used for internal combustion engine experiment or for the evaluation of any fuel injector static flow rate. Herewith a new term Injector-Volume Ratio (IVR) was introduced to assist the development process. Using the custom-built fuel injection controller, the static flow rate of an injector for a single cylinder 125cc motorcycle engine was determined in accordance to SAEJ1832. From the experiment, the IVR value is proven useful in choosing the right size of a fuel injector to fit any specified engine displacement of a spark ignition engine.

Lattice BGK Computational Method for Solving Natural Convection Heat Transfer from a Heated Non-concentric Annulus Cylinder

In this paper, we report the fluid flow behavior and characteristic of heat transfer from a heated inner cylinder placed eccentrically inside cold outer cylinder. The double distribution function lattice Boltzmann numerical scheme with the simplest lattice structure is applied to predict the velocity and temperature fields in the system. Six numerical experiments were preformed in order to study these phenomena with different locations of heated inner circular cylinder. In current study, we found that the vortex formation, size and strength are significantly affected by the location of heated inner cylinder. However, the convection mode heat transfer dominates the heat transfer mechanism for every simulation condition due to relatively high Rayleigh number condition applied in this study.