Search Results

The current research focuses on enhancing the performance of Si solar cells by using Er2O3 (Erbium Oxide) in cubic crystalline nature serves as an anti-reflection coating material. An anti-reflective coating aims to improve the Efficient Power Conversion (EPC) of polycrystalline silicon wafers solar cells (PSSC) utilised in solar roof panels of the automotive sector. It also exhibits superior light transmittance and least light reflectance, which eventually leads to the increase EPC. Erbium oxide helps to convert low energy photons into high energy photons. The incident photons, which lies on the solar cell, gradually losses its energy to travel in a denser medium and dissipate in the form of heat energy. In order to overcome the rate of reflection, current research aims in synthesis of erbium oxide nanosheets using electrospinning deposition technique for varying deposition timings such as 1, 1.5 and 2 hours.

Copper is almost inevitable functional filler in the brake-material and efforts to replace it are continuing since it is now known as a hazard to the aquatic life. It is always desirable to search for ingredients for Cu-free brake-pads, which will be beneficial for friction-related properties and especially fade resistance. Attapulgite, is a mineral which was proven to be an excellent substitute for asbestos in brake-pads long back. However, hardly anything in details is reported on its exact role in controlling tribo-properties of friction materials (FMs). It was of interest, if it can be helpful in enhancing the performance of Cu-free FMs. Hence, in this work a series of brake-pads (five types) was formulated and developed with increasing amount of attapulgite (0, 5, 10 and 15 wt. %) by compensating with inert barite particles in Cu-free FMs. The parent composition was fixed and instead of Cu powder, 10 wt.% stainless steel powder was used.

This paper presents results from tests using a fuel injection system which uses an ultrasonic atomizer paired with a port fuel injector (PFI). This concept was tested on a four stroke 200 cc spark-ignited two-wheeler engine. A throttle body with a PFI mounted on it was added to the air intake path of the engine, replacing the conventional carburetor. The ultrasonic disc was mounted in such a way, that the injected fuel from the PFI, falls directly on the face of the disc. The atomizer and the PFI were timed and synchronized appropriately using an Arduino® microcontroller, to promote atomization and vaporization of the fuel injected. The atomizer disc was excited using a high frequency oscillator circuit. The engine could be tested at various speeds and loads, corresponding to points which lie on the local drive duty cycle. The engine test results showed improvement in the engine exhaust emissions.

Flow variations from one cycle to the next significantly influence the mixture formation and combustion processes in engines. Therefore, it is important to understand the fluid motion and its cycle-to-cycle variations (CCVs) inside the engine cylinder. Researchers have generally investigated the cycle-to-cycle flow variations in moderate- to large-sized engines. In the present work, we have performed the flow measurement and analysis in a small spark-ignition engine. Experiments are conducted in an optically accessible, single-cylinder, port-fuel-injection engine with displacement volume of 110 cm3 at different throttle openings (i.e. 50% and WOT) using particle image velocimetry. Images are captured at different crank angle positions during both intake and compression strokes over a tumble measurement plane, bisecting the intake and exhaust valves and passing through the cylinder axis.

In a direct-injection (DI) engine, charge motion and mixture preparation are among the most important factors deciding the performance and emissions. This work was focused on studying the effect of injector positioning on fuel-air mixture preparation and fuel impingement on in-cylinder surfaces during the homogeneous mode of operation in a naturally aspirated, small bore, 0.2 l, light-duty, air-cooled, four-stroke, spark-ignition engine modified to operate under the DI mode. A commercially available, six-hole, solenoid-operated injector was used. Two injector locations were identified based on the availability of the space on the cylinder head. One location yielded the spray-guided (SG) configuration, with one of the spray plumes targeted towards the spark plug. In the second location, the spray plumes were targeted towards the piston top in a wall-guided (WG) configuration so as to minimize the impingement of fuel on the liner.

Diesel particulates are mainly composed of elemental carbon (EC) and organic carbon (OC) with traces of metals, sulfates and ash content. Organic fraction of the particulate are considered responsible for its carcinogenic effects. Diesel oxidation catalyst (DOC) is an important after-treatment device for reduction of organic fraction of particulates. In this study, two non-noble metal based DOCs (with different configurations) were prepared and evaluated for their performance. Lanthanum based perovskite (LaMnO3) catalyst was used for the preparation of DOCs. One of the DOC was coated with support material ceria (5%, w/w), while the other was coated without any support material. Prepared DOCs were retrofitted in a four cylinder water cooled diesel engine. Various emission parameters such as particulate mass, particle number-size distribution, regulated and unregulated emissions, EC/OC etc., were measured and compared with the raw exhaust gas emissions from the prepared DOCs.

There is a growing need for improved conceptual vehicle designs along with alternative materials to reduce the damage to the passengers and structures in aerospace and automotive industries. The energy absorption characteristics of materials play a major role in designing a safe vehicle for transport. In this paper, compression behavior and energy absorption of aluminum alloy AA6061 and AA7005 tubes in T4 and T6 conditions are investigated by experimental and numerical methods. The AA7005 and AA6061 tubes are solution heat treated and then aged to achieve the final strength in T6 condition. Experimental compression test results have shown improved energy absorption of tubes in T6 condition compared to tubes in T4 condition. There is less variation of energy among the tested samples. The mean load is compared with the results obtained from analytical formulae. Tensile properties have been obtained from tensile tests using UTM for both AA6061 and AA7005 tubes.

The effect of different cold- rolling and cryo-rolling routes on the strength and ductility of Al-6061 alloy was thoroughly investigated. Rolling decreased the grain size and increased the strength according to the Hall-Petch relationship. However subjecting the samples to ageing at different temperatures and for different time period increased the strength and improved the ductility. The ductility was improved due to the rearrangement and even decrease in dislocation density due to recovery and recrystallization during ageing while the strength was maintained due to ageing. Evolution of microstructure was investigated by optical microscopy, scanning electron microscopy. Preliminary hardness measurements coupled with tensile tests indicate the improvement of both yield strength and ductility. The disparity in ultimate tensile strength, yield strength and the elongation to failure with different ageing temperatures and for different time period is determined and discussed.

Formability of metals and alloys in general and aluminium alloys and steels in particular is of paramount importance in sheet metal forming in automobile industry. It is well understood that the evolution of preferred crystallographic orientation of crystallites or texture during prior thermo-mechanical processing of sheets plays an important role in determining formability. The formability of sheet is measured in terms of the Lankford parameter or the plastic strain ratio which is defined as the ratio of strain in width direction to that in the thickness direction (R = εw/εt). The variation of Lankford parameter with the rolling direction and standard and ΔR value is widely used in industry as a standard for estimating the formability of the rolled sheets.

The mechanical and wear behaviour of an alloyed gray cast iron with ausferrite microstructure directly obtained on solidification has been compared with austempered alloyed gray iron. As-cast ausferritic gray iron shows finer ausferrite and graphite flake morphology compared to austempered alloy. The volume of retained austenite is about 30% higher in as-cast ausferritic iron due to higher amount of alloying additions. The mechanical and wear properties of as-cast ausferritic iron are almost similar to austempered alloy.

Performance of a Current generation catalytic converter using Pd/Rh (10:1) as binary catalyst impeded on an ultra thin ceramic substrate and alumina wash coat is modeled for performance prediction and parametric optimization. Kinetic rates for the catalyst are reduced after conducting series of experiments on a passenger car engine. A new concept in mass transfer coefficient is introduced for improving accuracy of the model prediction. In order to take care of the precious metal resources and to become independent of precious metal price fluctuation, a new pattern of loading of precious metal is suggested for optimum performance and metal savings about 46 percent was observed. Experimental investigations were carried out to validate the established kinetic rates over a wide range operation of the engine and for the model validation. Satisfactory agreements are observed for the model prediction and experimental results.

Copper ion-exchanged X-zeolite with urea infusion was tested for nitrogen oxide (NOx)conversion efficiency in this study. Temperature datapoints were obtained to arrive at peak activation temperatures. Variation of the air/fuel ratio showed the widening of the λ-window(the range of air-fuel ratios over which the NOx conversion efficiency is considerable); a maximum of 62% NOx conversion efficiency was obtained in the lean-burn range. Effects of space velocity variations were also observed. In order to minimise the deactivation of zeolite caused by water, ammonium carbonate and ammonium sulphate were deposited on the copper ion-exchanged X-zeolite and the corresponding NOx conversion efficiencies measured. Ammonia slip (leakage of unreacted ammonia), a prospective pollution hazard, was observed to be more in case of urea infusion than ammonium salt deposition at higher temperatures.

Experimental investigations relating to the performance and emission characteristics under idling conditions of a three cylinder passenger car spark ignition engine operating on a conventional carburettor and a developed single point gasoline fuel injection system are described in this paper. The idling performance at different engine speeds was studied by carrying out comprehensive engine testing on a test bed in two phases. In the first phase, experiments were conducted on an engine fitted with a conventional carburettor whilst they were extended to the engine provided with a developed electronic single point fuel injection (SPI) system, whose fuel spray was directed against the direction of air flow. The injection timing of the SPI system was varied from 82 deg. before inlet valve opening (or 98 deg. before top dead center) to 42 deg. after inlet valve opening (or 26 deg. after top dead center).

Three catalysts based on X-zeolite have been developed by exchanging its Na+ ion with Copper, Nickel and Vanadium metal ions and tested in a stationary SI engine exhaust to observe their potentialities for NOx and CO controlling. The catalyst Cu-X, in comparison to Ni-X and V-X, exhibits much better NOx and CO reduction performance at any temperature. Maximum NOx conversion efficiencies achieved with Cu-X, Ni-X and V-X are 62.2%, 59.7% and 56.1% respectively. Unlike noble metals, the doped X-zeolite catalysts, studied here, maintain their peak NOx reduction performance through a wider range of A/F ratio. Back pressure developed across the catalyst bed is found to be well within the acceptable limits.

The performance of a conventional, carbureted, two-stroke spark-ignition (SI) engine can be improved by providing moderate thermal insulation in the combustion chamber. This will help to improve the vaporization characteristics in particular at part load and medium loads with gasoline fuel and high-latent-heat fuels such as methanol. In the present investigation, the combustion chamber surface was coated with a 0.5-mm thickness of partially stabilized zirconia, and experiments were carried out in a single-cylinder, two-stroke SI engine with gasoline and methanol as fuels. Test results indicate that with gasoline as a fuel, the thin ceramic-coated combustion chamber improves the part load to medium load operation considerably, but it affects the performance at higher speeds and at higher loads to the extent of knock and loss of brake power by about 18%. However, with methanol as a fuel, the performance is better under most of the operating range and free from knock.

The use of alcohol-gasoline blends enables the favorable features of alcohols to be utilized in spark ignition (SI) engines while avoiding the shortcomings of their application as straight fuels. Eucalyptus and orange oils possess high octane values and are also good potential alternative fuels for SI engines. The high octane value of these fuels can enhance the octane value of the fuel when it is blended with low-octane gasoline. In the present work, 20 percent by volume of orange oil, eucalyptus oil, methanol and ethanol were blended separately with gasoline, and the performance, combustion and exhaust emission characteristics were evaluated at two different compression ratios. The phase separation problems arising from the alcohol-gasoline blends were minimized by adding eucalyptus oil as a co-solvent. Test results indicate that the compression ratio can be raised from 7.4 to 9 without any detrimental effect, due to the higher octane rating of the fuel blends.

Hydrocarbon emissions due to short-circuiting of the fresh charge during scavenging process is a major source of pollution from the two-stroke spark ignition engines. This work presents a prediction scheme for analysis of hydrocarbon emission based on the material balance considerations. A generalized form of globular combustion equation has been used for general applicability of the scheme to any fuel or fuel blends. The influence of mixture quality, scavenging characteristics, residual contents and the delivery ratio are predicted. A good qualitative prediction has been established at all delivery ratios. The predictions are found quantitatively satisfactory in the higher delivery ratio range where the short-circuiting phase of the scavenging process is dominant.

Use of methanol and ethanol in conventional diesel engines is associated with problems on account of the high self ignition temperature of these fuels. The Hot Surface Ignition (HSI) method wherein a part of the injected fuel is made to touch an electrically heated hot surface for ignition, is an effective way of utilizing these fuels in conventional diesel engines. In the present work two types of HSI engines, one using a large ceramic base and the other using a conventional glowplug were developed. These engines were tested with methanol, M.spirit (about 90 % methanol and 10 % ethanol) and diesel. The results of performance, fuel economy emissions and combustion parameters including heat release rates for these fuels with both the types of HSI engines are presented. Diesel engines are commonly used as primemovers in the mass transportation and agricultural sectors because of their high brake thermal efficiency and reliability.