D. Ramasamy

Variation Of Airflow Pattern Through Dissimilar Valve Lift In A Spark Ignition Engine

Abstract Bi-fuel conversions are a common alternative fuelling option for mono-fuel gasoline SI vehicles because of the minor vehicle modifications required. In Malaysia, most bi-fuel vehicles are fuelled with compressed natural gas (CNG) and gasoline. However, CNG flame speed is lower than gasoline reducing the power and range of the vehicle when operating on CNG. This situation can be improved by increasing the flame speed via higher swirl generation. A Computational fluid dynamics model is used to analyse swirl generated by dissimilar valve lift (DVL) profiles on the intake valve. A three-dimensional engine simulation shows differences in swirl motion and turbulence between the original symmetric valve lift profile and the DVL. The higher swirl number reduces the turbulence kinetic energy level slightly. The best case profile is selected for further experimental testing.

The Application of Response Surface Methodology in the Investigation of the Tribological Behavior of Palm Cooking Oil Blended in Engine Oil

The purpose of this study was to determine the optimal design parameters and to indicate which of the design parameters are statistically significant for obtaining a low coefficient of friction (COF) and low wear rate with waste palm oil blended with SAE 40. The tribology performance was evaluated using a piston-ring-liner contact tester. The design of experiment (DOE) was constructed by using response surface methodology (RSM) to minimize the number of experimental conditions and to develop a mathematical model between the key process parameters such as rotational speeds (200 rpm to 300 rpm), volume concentration (0% to 10% waste oil), and applied loads (2 kg to 9 kg). Analysis of variance (ANOVA) test was also carried out to check the adequacy of the empirical models developed. Scanning electron microscopy (SEM) was used to examine the damage features at the worn surface under lubricant contact conditions.

Mass Fraction Burn Comparison of Compressed Natural Gas and Gasoline

Vehicle efficiency relates to pollutants and cost savings in third world countries. In term of subcompact cars, the vehicle characteristics are governed by the engine for alternative fuels. The main focus of this paper was to evaluate a sub compact car engine for its performance and burn rate of gasoline and Compressed Natural Gas (CNG). A bi-fuel sequential system was used to do this evaluation. Measurements of engine speed, torque and fuel were done on an eddy current dynamometer, while measurements or in-cylinder pressure, crank angle and spark were analyzed from results taken by data acquisition system. The emissions readings were also compared from an emission analyzer. The results were analyzed for burn rate based on the first law of thermodynamic. The comparison shows a drop of 18.6% was seen for the power, brake specific fuel consumption (BSFC) loss was 7% and efficiency loss was at 17.3% in average for all engine speed. Pressure analysis shows peak pressure dropped by 16%. Burn rate shows why CNG had a slower burning speed on the small engine. The engine speed of 4000 rpm at Maximum Brake Torque (MBT) produced the most nearest results to gasoline.

Heat Transfer Enhancement with Nanofluids for Automotive Cooling

The increasing demand of nanofluids for the industrial applications has led to focus on it from many researchers in the last decade. This thesis includes both experimental study and numerical study to improve heat transfer with slightly pressure drop in the automotive cooling system. The friction factor and heat transfer enhancement using different types of nanofluids are studied. The TiO2 and SiO2 nanopowders suspended to four different base fluids (pure water, EG, 10 %EG + 90 %W, and 20 %EG + 80 %W) are prepared experimentally. The thermophysical properties of both nanofluids and base fluids are measured and validated with the standard and the experimental data available. The test section is setup including car radiator and the effects under the operating conditions on the heat transfer enhancement analyzed under laminar flow condition. The volume flowrate, inlet temperature, and nanofluid volume concentrations are in the range of (1-5LPM) for pure water and (3-12LPM) for other base fluids, (60–80 °C) and (1–4 %), respectively. On the other side, the CFD analysis for the nanofluid flow inside the flat tube of a car radiator under laminar flow is carried out. A simulation study is conducted by using the finite volume technical to solve the continuity, momentum, and energy equations. The processes of the geometry meshing of problem and describing the boundary conditions are performed in the GAMBIT then achieving of FLUENT software to find the friction factor and heat transfer coefficient. The experimental results show the friction factor decreases with the increase of the volume flowrate and increases with the nanofluid volume fraction but slightly decreases with the increase of the inlet temperature. Furthermore, the simulation results show good agreement with the experimental data with deviation, not more than 4 %. The experimental results show that the heat transfer coefficient increases with the increase in the volume flowrate, the nanofluid volume fraction, and the inlet temperature. Likewise, the simulation results show good agreement with the experimental data with deviation not more than 6 %. In addition, the SiO2 nanofluid appears high values of the friction factor and heat transfer coefficient than TiO2 nanofluid. Also, the base fluid (20 %EG + 80 %W) gives high values of the heat transfer coefficient and proper values of friction factor than other base fluids. It seems that the SiO2 nanoparticles dispersed to (20 %EG + 80 %W) base fluid are a significant enhancement of the thermal properties than others. It is observed that the SiO2 nanoparticles dispersed to (20 %EG + 80 %W) base fluid are a significant augmentation of heat transfer in the automobile radiator. The regression equations among input (Reynolds number, Prandtl number, and nanofluid volume concentration) and response (friction factor and Nusselt number) are found. The results of the analysis indicated a significant input parameters to enhance heat transfer with the automotive cooling system. The comparison between experimental results and other researchers’ data is conducted, and there is a good agreement with a maximum deviation approximately 10 %.

Experiments on Dissimilar Valve Lift (DVL) for Turbulence Increment on a Bi-Fuel Compressed Natural Gas (CNG) Engine

Current engines are readily available for CNG bi-fuel conversions because it requires only minor engine modifications. However, CNG flame speed is lower than gasoline, therefore reducing the power and range of the vehicle when operating on CNG. This situation can be improved by increasing the flame speed via higher turbulence generated by swirl motion. A computational fluid dynamics (CFD) model was used to analyse the swirl generated by dissimilar valve lift (DVL) profiles on the intake valve. A 3D engine simulation shows differences in swirl motion and turbulence between the original symmetric valve lift profile and the DVL. The swirl before combustion was found to increase almost 25%. The higher swirl number can increase the turbulence kinetic energy (TKE) level which improves better fuel mixing. The 1 mm DVL proved to be the better choice from CFD analysis and later was tested on a K3-VE engine. Pressure analysis shows peak pressure increased by 5.6% and burn rate shows CNG had a slower burning speed on the small engine

Optimization on Wear Performance of Anti Wear Additive Added Biolubricant

Waste cooking oil is hard to dispose of and harmful to the environment. Recently, a considerable amount of research has been done to improve the properties of engine oil. In this study, engine oil was blended with waste cooking oil and an oil treatment solution. The blended oil was tested in a tribological wear tester. There are three parameters (rotational speed, loads and ratio of waste cooking oil) was consider in the experiments. Tribology wear and properties of the blended oil were investigated in FESEM. It was found that abrasive wear, adhesive wear, fatigue wear and corrosive wear were introduced during the course of the experiments. Normally, corrosive wear was found to be the main dominant in the tribology wear. It was discovered that 5% addition of waste oil to the engine oil treatment and base lubricant performed better than other oil blends.

The two-stroke poppet valve engine. Part 1: Intake and exhaust ports flow experimental assessments

A two-stroke poppet valve engine is developed to overcome the common problems in conventional two-stroke engine designs. However, replacing piston control port with poppet valve will resulted different flow behaviour. This paper is looking at experimental assessment on a two-stroke poppet valve engine configuration to investigate the port flow performance. The aims are to evaluate the intake and exhaust coefficient of discharge and assess the twostroke capability of the cylinder head. The results has shown comparable coefficient of discharge values as production engine for the intake while the exhaust has higher values which is favourable for the two-stroke cycle operation.

Effect of the length on the tensile deformation of nickel nanowires using molecular dynamics simulations

In the recent years, with the fast advancement in the fields associated with nanoscience and nanotechnology, metal nanowires, in specific have received enormous attention among researchers due to their fascinating properties and applications. In this study, the Young Modulus and failure behavior of Nickel (Ni) nanowires 7.04 nm in diameter with eight (8) different lengths (17.60, 21.12, 24.64, 28.16, 31.68, 35.20, 52.80 and 70.40 nm) were successfully modeled for uniaxial tensile tests using Molecular Dynamic (MD) simulations. MD simulations were performed at a fixed point of the temperature of 300 K and a constant strain rate of 0.0001 ps-1. The finding showed that these Ni nanowires have a Young Modulus between 140.02 to 142.5 GPa. We strongly believe that the variation of the length model has no significant influence on neither the Young Modulus nor the failure behavior. All the investigated nanowires demonstrated ductile failure behavior type, in which represents a typical behavior of Ni at bulk scales.