Search Results

In engine 30% of the total energy is lost due to the friction between piston ring and cylinder liner due to their constant rubbing motion. A piston that reciprocates at high speeds has piston rings that constantly scrape against the wall leading to high frictional losses within the engine. The engine has to work against this resistance to provide the required power, and hence it will consume more fuel. For this reason, material used for these components is more crucial. Reduction of surface friction between moving parts in order to increase overall efficiency can be achieved by suitable coating. The most commonly used piston rings are coated with chromium layers that are electroplated which is being replaced by chrome plating. Low coefficient of friction (COF) and high wear resistance can be achieved by self-lubricating coating of PTFE and PEEK polymer-based composite coatings.

Considering the advancements in manufacturing industries, which are crucial for economic growth, there is a substantial demand for exploration and analysis of advanced materials, especially alloy materials, to enable efficient utilization of new technologies. Lightweight and high-strength materials, like aluminum alloys, are highly recommended for various applications that necessitate both strength and resistance to corrosion, such as automobile, marine and high-temperature applications. Therefore, there is a significant need to investigate and analyze these materials to facilitate their effective application in manufacturing sectors. This study investigates the machinability of drilling AA6061 using a micro-textured uncoated tool and proposes an Adaptive Neuro Fuzzy Inference System (ANFIS) model for investigating the machinability of drilling AA6061 aluminum alloy with a micro-textured uncoated tool.

During investigation of an automotive shock absorber endurance test where it was supposed to last at least 200,000 load cycles but that did not meet the mandatory fatigue requirement. This is because of the failure in the shock absorber shim assembly. This failure was due to Fretting fatigue. Design improvement is carried out to avoid the fretting fatigue phenomenon on the shock absorber shim assembly. Using FEA some analysis is done over the shim assembly to determine the stress region. At last after increasing the shims in the piston important improvement in fatigue life was achieved. This improvement was obtained with simple solution, without effecting the damping forces.

Heat transfer optimization is a crucial aspect of the design process for Formula Student race cars, particularly for the radiator, usually housed in a side pod. For the car to operate at peak performance, a well-designed radiator-sidepod system is essential such that it can dissipate heat generated by the engine faster, for the car to run in optimal performance. Testing the car physically for various radiator-sidepod design iterations is a very difficult task, also considering the costs to manufacture the radiator-sidepod setup. Computational Fluid Dynamics can be used to simulate and analyze the fluid flow and heat transfer in the setup, and can also find out the impact of changing the parameters of the radiator and sidepod, without any expenditure. It can also consider various environmental factors, which can’t be accounted for in theoretical calculations with ease.

A wide range of engineering sectors, such as aerospace, automobiles, and marine, rely on the use of metal Matrix Composites. Due to its superior properties, such as hardness and strength, Aluminum Metal Matrix Composites are commonly used in various applications. The light weight to high strength ratio, reduced coefficient of friction and wear rate, corrosion resistance, easy to fabricate are some of the important properties of Al hybrid metal matrix composite which can be used in the automobile systems such as piston liners, camshaft, piston, engine body, valve covers. The analysis of the machinability of the composite was also performed. The process of creating a new MMC using a stir casting technique was carried out. It resulted in a better and more reinforced composite than its base materials. The reinforcement materials were fabricated using different weight combinations and process parameters, such as the temperature and time needed for stirring.

This study aims to investigate the effect of hydrogen injection to palm oil biodiesel on a compression ignition (CI) engine's exergy efficiency, while assessing its sustainability index. The tests are performed on a diesel engine with a single cylinder cooled by water and run at a consistent speed of 1500 rpm, with a load range varying from 0.01 kg to 18 kg, and hydrogen injection rates ranging from 4 lpm to 10 lpm. The findings reveal that biodiesel has higher exergetic efficiency when compared to conventional diesel. The biodiesel-run CI engine has an exergetic efficiency of 31.6%, and a sustainability index of 1.236 at the maximum brake power of 5.2 KW. Exergy analysis is conducted for shaft work, cooling water, exhaust gas availability, and entropy generation. The study also investigates the variation in the engine cylinder's peak pressure and heat release rate, as well as the performance metrics of the engine, like brake thermal efficiency and temperature of the exhaust gas.

Titanium alloys are lightweight materials preferably used in transportation due to its high corrosion resistance and thermal strength. Titanium and its alloys are primarily used in internal combustion engine components, such as valves, valve spring, retainers, and connecting rods. Grade 5 applications include aircraft, automobile components, tennis racquets, golf club shafts, ski plates, and bicycles. The goal of this project is to optimise the machining parameters of Wire cut Electrical Discharge Machining (WEDM) used to machine Ti-6Al-4V (Grade 5) compound with brass wire to achieve the lowest surface roughness and highest material removal rate possible. The L9 orthogonal array is used, with input variables such as pulse-on time (s), pulse-off time (s), and peak current, and output variables such as material removal rate (MRR) and surface roughness (RA).

Methanol is a suitable alternative fuel to relieve the problem of energy shortage and decrease the emission of greenhouse gases. The effect of direct injection timing of methanol and diesel on the combustion characteristics of a marine diesel engine with bore of 0.21 m was simulated with a 3-dimentional computational fluid dynamic (CFD) software AVL-FIRE. The combustion model was set-up and validated by the experimental data from the marine diesel engine. Results show that there are two peaks on the heat release rate (HRR) curves with the normal diesel-methanol combustion process. The first HRR peak is caused by the combustion of diesel. The second HRR peak is resulted from the hybrid combustion process of diesel and methanol. The injection timing of diesel influences the maximum pressure rise rate (PRRmax) and ignition timing.

Rotary valve technology can provide increased flow area and higher discharge coefficients than conventional poppet valves for internal combustion engines. This increase in intake charging efficiency can improve the power density of four-stroke internal combustion engines, particularly at high engine speeds, where flow is choked through conventional poppet valves. In this work, the valvetrain of a light duty single cylinder spark ignition engine was replaced with a rotary valve train. The impact of this valvetrain swap on performance and emissions was evaluated by comparing spark timing sweeps with lambda ranging from 0.8 to 1.1 at wide open throttle. The results indicated that the rotary valvetrain increased the amount of air trapped at intake valve closing. The results also indicated that the rotary valvetrain resulted in a significantly faster burn duration than the conventional valvetrain.

The internal combustion engine contains several actuators to control the engine performance and emissions. These are controlled within the engine control unit and follow a certain operation strategy to achieve targets such as reduction of NOx emissions and fuel consumption. However, these two targets are contradictory, and a compromise is required. The operation state is depending on the system boundaries, such as engine speed, load, temperature levels and exhaust aftertreatment system efficiency. This leads to constantly changing target values to remain within the defined boundaries, in particular the legal emission limits. The conventional approach is using several operating modes. Each mode represents a specific compromise and is activated accordingly. To fulfil the emissions legislation, multiple modes are required, which increases the calibration efforts. This new control approach uses an artificial neural network that replaces the conventional multiple operation mode approach.

This paper presents a method to analyse the characteristics of nano-scale particles emitted from a 1.6 Litre, 4-stroke, gasoline direct injection (GDI) and turbocharged spark ignition engine fitted with a three-way catalytic converter. Ensemble Empirical Mode Decomposition (EEMD) is employed in this work to decompose the nano-scale particle size spectrums obtained using a differential mobility spectrometer (DMS) into Intrinsic Mode Functions (IMF). Fast Fourier Transform (FFT) is then applied to each IMF to compute its frequency content. The results show a strong correlation between the IMFs of specific particle ranges and the IMFs of the total particle count at various speed and load operating conditions. Hence, it is possible to characterise the influence of specific nano-scale particle ranges on the total particulate matter signal by analysing the frequency properties of its IMFs using the EEMD-FFT method.

Pre-chamber ignition is one of the significant factors to improve the combustion performance for lean combustion natural gas (NG) engine, which could achieve low NOx, simultaneously. The designing scheme of the orifices, which connects the pre-chamber and the main-chamber, is the main challenge limiting the further improvement. In this work, the three-dimensional computational fluid dynamics (3D CFD) calculation based on a four-stroke engine with 320 mm cylinder bore was conducted to investigate the effects of orifice structure on the combustion and NOx performance. The results show that the odd orifice number (7 and 9) scheme leads to the delayed high-temperature jets formation due to the asymmetrical airflow in the pre-chamber, which retards the ignition timing and enhances the combustion in the main-chamber.

Catalytic converters, which are commonly used for after-treatment in SI engines, exhibit poor performance at lower temperatures. This is the main reason that tailpipe emission drastically increase during cold-start periods. Exhaust enthalpy management is very crucial for turbocharged DISI engines during cold-start periods to quickly heat up the catalyst because to minimize cold-start emissions. Thermal barrier coatings (TBCs), because of their low thermal inertia, can increase surface temperatures more quickly than metal walls and thereby block heat transfer, saving enthalpy for the catalyst. A multi-cylinder GT-Suite model of a Ford Eco-boost 2.3 L engine was built with focus on capturing heat transfer and surface temperatures of combustion chamber, intake and exhaust flow paths, turbocharger casing and catalyst surface. Cold-start operating conditions significantly differ from normal operating conditions for faster engine warm-up.

An investigation of the performance and emissions of a Fischer-Tropsch Coal-to-Liquid (CTL) Iso-Paraffinic Kerosene (IPK) was conducted using a CRDI compression ignition research engine with ULSD as a reference. Due to the low Derived Cetane Number (DCN), of IPK, an extended Ignition Delay (ID), and Combustion Delay (CD) were found for it, through experimentation in a Constant Volume Combustion Chamber (CVCC). Neat IPK was analyzed in a research engine at 4 bar Indicated Mean Effective Pressure (IMEP) at three injection timings: 15°, 20°, and 25° BTDC. Combustion phasing (CA50) was matched with ULSD at 6°, 10.8°, and 16° BTDC. The IPK DCN was found to be 26, while the ULSD DCN was significantly higher at 47 in a PAC CID 510. In the engine, IPK’s DCN combined with its short physical ignition delay and long chemical ignition delay compared to ULSD, caused extended duration in Low Temperature Heat Release (LTHR) and cool flame formation.

In this study, the lubrication properties of the Fischer-Tropsch Gas-to-Liquid alternative fuel, Synthetic Paraffinic Kerosene (S8), Jet- A, and Ultra Low Sulfur Diesel (ULSD) were investigated using a pin-on-disk tribometer and analyzed for friction force overtime and the measurement of removed material weight after each test of the disk. Alternative fuels are known for producing lower emissions and having fewer toxic contaminants than fossil fuels. The lubricity of fuels plays a crucial role in the function of a fuel pump, injectors, flow meters, and engine moving parts. For each investigation, the tribometer was run for 15 cycles for each of the researched fuels. The sample was submerged in 10 grams of fuel for each cycle to ensure complete coverage of the sample disk. A Keyence VHX-1000 Microscope was used to compare the visual wear patterns and severities of AISI 1018 Steel Disks.

An investigation into emissions differences and their correlations with differing combustion characteristics between Jet-A and F-24 was conducted. A constant volume combustion chamber was used for combustion characteristics. The derived cetane number (DCN) for Jet-A was determined to be 47.0 with an ignition delay (ID) of 3.35ms and a combustion delay (CD) of 5.14 ms compared to F-24 with a DCN of 43.4, an ID of 4.10 ms, and a CD of 5.79 ms. F-24 had a longer low temperature heat release (LTHR) region and a lower peak in its high temperature heat release region (HTHR). Raw emissions data was taken from a single stage jet engine by a FTIR gas analyzer and compared with a simulation using Jet-A. Measurements of H2O, CO2, CO, NOx, and total hydrocarbon emissions (THC) were taken at 60K, 65K, and 70K RPM. At 70K RPM Jet-A and F-24 the emissions were similar at approx.: 4% H2O, 3% CO2, 970 PPM CO, 28 PPM NOx.

In this work, a novel journal bearing test rig was used to evaluate the impact of oil viscoelasticity on friction torque and oil film thickness in a hydrodynamic journal bearing. The test rig used an electric motor to rotate a test journal, while a hydraulic actuator applied radial load to the connecting rod bearing. Lubrication of the journal bearing was accomplished via a series of axial and radial drillings in the test journal, replicating oil delivery in a conventional engine crankshaft. Journal bearing inserts from a commercial, medium duty diesel engine (Cummins ISB) were used. Oil film thickness was measured using high precision eddy current sensors. Oil film thickness measurements were taken at two locations, allowing for calculation of minimum oil film thickness. A high precision in-line torque meter was used to measure friction torque. Four test oils were prepared and evaluated.

This work for the Coordinating Research Council (CRC) explores dependencies on the opportunity for fuel to impinge on internal engine surfaces (i.e., fuel–wall impingement) as a function of fuel properties and engine operating conditions and correlates these data with measurements of stochastic preignition (SPI) propensity. SPI rates are directly coupled with laser–induced florescence measurements of dye-doped fuel dilution measurements of the engine lubricant, which provides a surrogate for fuel–wall impingement. Literature suggests that SPI may have several dependencies, one being fuel–wall impingement. However, it remains unknown if fuel-wall impingement is a fundamental predictor and source of SPI or is simply a causational factor of SPI. In this study, these relationships on SPI and fuel-wall impingement are explored using 4 fuels at 8 operating conditions per fuel, for 32 total test points.

With the constant strive towards increase in performance and corresponding stringent emission standards of modern IC engine, engine components such as the head, block and piston are subjected to higher thermal loads. This is why it is important to mitigate failures early in the design cycle of any engine program. An integrated simulation methodology is proposed where the head, the block and the piston are integral part of the analysis. The CFD – CHT methodology is used to simulate and predict the temperature of these engine components. The head and block are run in a steady-state conjugate heat transfer framework while the transient multiphase volume of fluid (VOF) approach is used to predict piston temperatures. Combustion surfaces boundary conditions are derived from 3D CFD open-loop combustion simulation, while cooling and lubrication surface boundary condition are mapped from 1D system simulation or experimental data.

As a biofuel, methanol is an interesting alternative for internal combustion engines (ICE). In spite of drawbacks such as misfiring or instabilities at low loads, methanol has a number of advantages. Today, dual-fuel systems allow the use of methanol in combination with diesel fuel. This paper will present a different approach, the ability to use methanol in a flex-fuel system. Addition of a combustion enhancer containing alkyl nitrate (CEN) allows the use of methanol in a direct injection compression ignition (DICI) engine without any changing. In this paper, different volume fractions of this additive are tested. The aim is to show the effect of the CEN on the combustion of methanol. The effect of CEN on methanol has been confirmed thanks to previous tests carried out on a rapid compression machine. Ignition delay times (IDT) and auto-ignition temperature were reduced with a small amount of CEN.