Mas Fawzi

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.

Effect of Air Movement to Spray Development of Rapeseed Oil in Diesel Engine

Fuel-air mixing is important process in diesel combustion. Generally there a two air mixing strategy, which is slow fuel – fast air mixing and fast fuel – slow air mixing. Air movement inside the combustion chamber greatly affect the mixing process and made effective fuel air mixing possible. Biomass fuel needs great help of mixing to atomization because the fuel has high viscosity and high distillation temperature. This study investigates the effect of air movement to spray development and atomization characteristics of rapeseed oil (RO). Optical observation of RO spray was carried out using shadowgraph photography technique and also using high speed camera. The results show that fast air movement effectively promotes RO spray atomization, with the RO spray expand outward from the main body through the whole spray length, which suggests fuel dispersion due to fast air movement.

Experimental Investigation of Emissions Characteristics of Small Diesel Engine Fuelled by Blended Crude Palm Oil

Biodiesel is an alternative, decomposable and biological-processed fuel that has similar characteristics with mineral diesel which can be used directly into diesel engines. Crude palm oil (CPO) is one of the vegetable oil that has potential for use as a fuel in diesel engine. However, Biodiesel is also an oxygenated fuel and more density, viscosity meaning it contains influences the emissions production during burning process. Despite years of improvement attempts, the key issue in using crude palm oil fuels is oxidation stability, high viscosity and much oxygen comparing to diesel fuel. Thus, the improvement of performance and emission exhausted from biodiesel fuels is urgently required to meet the future performance and emission regulations. Purpose of this study is to explore how significant the effect of biodiesel blends on the exhaust emission with different speed. The engine speed was varied from 1500-2500 rpm and CPO blending ratio from 5-15 vol% (B5-B15).The emission parameter have been tested in term of opacity, hydrocarbon (HC), nitrogen oxide (NOX), carbon dioxide (CO2 ) and oxygen (O2). Increased blends of biodiesel ratio is found to enhance the combustion process, resulting in decreased the HC emissions and also other exhaust emission element. The improvement of combustion process is expected to be strongly influenced by oxygenated fuel in biodiesel content.

A numerical analysis of flat fan aerial crop spray

Spray drift mitigation, in the agriculture aerial spraying literature, and spray quality in the application of plant protection products, still continues as two critical components in evaluating shareholder value. A study on off-target drift and ground deposit onto a 250 m strip were simulated through series of Computational Fluid Dynamic (CFD) simulations. The drift patterns for evaporating droplets were released from a constant aircraft velocity at 30 m/s (60 mph) carrying 20 m swath width spray boom with 12 fan-type nozzles at released height from the ground ranging from 3.7 m to 4.7 m. Droplet trajectories are calculated from the given airspeed with a Lagrangian model for particle dispersion excluding any wind effect perturbation. The proposed CFDs model predictions agreed well with cited literatures for a wide range of atmospheric stability values. The results revealed that there is considerable increased in spray drift and droplets trajectories with the increased in spray released height. It suggested that a combination of low aircraft spray released height with low airspeed is essential to improve spray quality and maximizing uniform deposition on the target area are significant in minimizing spray drift risks.

Thermal Imaging of Flame in Air-assisted Atomizer for Burner System

Infrared thermography was used as a part of non-intrusion technique on the flame temperature analysis. This paper demonstrates the technique to generate the thermal images of flame from the air-assisted atomizer. The multi-circular jet plate acts as a turbulence generator to improve the fuel and air mixing in the atomizer. Three types of multi-circular jet plate geometry were analysed at different equivalence ratio. Thermal infrared imaging using FLIR thermal camera were used to obtain the flame temperature. Multi-circular jet 1 shows the highest flame temperature obtained compared to other plates. It can be concluded that the geometry of the plate influences the combustion, hence affects the flame temperature profile from the air-assisted atomizer.

Dual fuel injection piggyback controller system

Dual-fuel injection is an effort to reduce the dependency on diesel and gasoline fuel. Generally, there are two approaches to implement the dual-fuel injection in car system. The first approach is changing the whole injector of the car engine, the consequence is excessive high cost. Alternatively, it also can be achieved by manipulating the system’s control signal especially the Electronic Control Unit (ECU) signal. Hence, the study focuses to develop a dual injection timing controller system that likely adopted to control injection time and quantity of compressed natural gas (CNG) and diesel fuel. In this system, Raspberry Pi 3 reacts as main controller unit to receive ECU signal, analyze it and then manipulate its duty cycle to be fed into the Electronic Driver Unit (EDU). The manipulation has changed the duty cycle to two pulses instead of single pulse. A particular pulse mainly used to control injection of diesel fuel and another pulse controls injection of Compressed Natural Gas (CNG). The test indic...

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.

Heating and cooling of an aluminium-cased parallel flow microreactor for steam-methane reforming

A prototype aluminium microreactor for steam methane reforming process to produce hydrogen syngas, with parallel flow microchannels was developed. The microreactor was heated up to 400°C using a Bunsen burner at distance of 10mm below it surface. Whereby two condition of burner open flow which are 1/3 and 2/3 took place in order to investigate its heating effect on outlet stream temperature. From the results, show that both Bunsen burner flow slightly show the same tendency of increasing and decreasing state, which indicated the optimum point of heat transfer to the systems for a cycle. But, the 2/3 opening Bunsen burner flow give the reliable contact reaction time at minimum operating condition of 400 °C and 1 bar compare to 1/3 opening. This is due to its ability for lays above the set temperature point with longest duration time. From this results can conclude that, the relationship between contact flame area and microreactor surface on outlet flow temperature had been developed. The outlet stream temperature is proportional to the Bunsen burner opening, based on biggest area of flame contact yield the highest optimum temperature point with longest reaction time.

Measurement of Thermophoretic Velocity in Surrounding Gas of Nitrogen or Carbon Dioxide

Several experiments are conducted under the microgravity condition, which is achieved by a free-fall, for measuring the thermophoretic velocity in surrounding gas of nitrogen and carbon dioxide. PMMA spheres are used as measured particles, which are 2.91μm in mean diameter. The temperature gradient is 10 K/mm and the pressure is the range between 20 kPa and 100 kPa. Velocities of particles are individually measured during 0.25 s of the microgravity condition and the measurements are repeated in order to attain the accuracy by accumulating data. Comparison between obtained experimental results and theoretical predictions are done; the result for nitrogen is consistent with prediction, while a notable discrepancy is found for carbon dioxide. The disagreement is fixed by modifying the tangential momentum accommodation coefficient.