The fuel economy of recent small size DI diesel engines has become more and more efficient. However, heat loss is still one of the major factors contributing to a substantial amount of energy loss in engines. In order to a full understanding of the heat loss mechanism from combustion gas to cylinder wall, the effect of hole size and rail pressure under similar injection rate conditions on transient heat flux to the wall were investigated. Using a constant volume vessel with a fixed impingement wall, the study measured the surface heat flux of the wall at the locations of spray flame impingement using three thin-film thermocouple heat-flux sensors. The results showed that the characteristic of local heat flux and soot distribution was almost similar by controlling similar injection rate except for the small nozzle hole size with increasing injection pressure.
In the present work, a relative comparison of addition of water to diesel through emulsion and fumigation methods is explored for reducing oxides of nitrogen (NOx) and smoke emissions in a production small bore diesel engine. The water to diesel ratio was kept the same in both the methods at a lower concentration of 3% by mass to avoid any adverse effects on the engine system components. The experiments were conducted at a rated engine speed of 1500 rpm under varying load conditions. A stable water-diesel emulsion was prepared using a combination of equal proportions (1:1 by volume) of Span 80 and Tween 80. The mixture of Span 80 in diesel and Tween 80 in water was homogenized using an IKA Ultra Turrax homogenizer with tip stator diameter 18mm at 5000 rpm for 2 minutes. The water-in-diesel emulsions thus formulated were kinetically stable and appeared translucent. No phase separation was observed on storage for approximately 105 days.
Gray cast iron brake rotor experiences substantial wear during the braking and contributes largely to the wear debris emissions. Surface coating on the gray cast iron rotor represents a trending approach dealing with the problems. In this research, a new plasma electrolytic aluminating (PEA) process was used for preparing an alumina-based ceramic coating with metallurgical bonding to the gray cast iron. Three different types of brake pads (ceramic, semi-metallic and non asbestos organic (NAO)) were used for tribotests. Performances of PEA coatings vs. different brake pad materials were comparatively investigated with respect to their coefficients of friction (COFs) and wear. The PEA-coated brake rotor has a dimple-like surface which promotes the formation of a thin transferred film to protect the rotor from wear. The transferred film materials come from the wear debris of the pads. The secondary plateaus are regenerated on the brake pads through compacting wear debris of the pads.
Measuring brake emission is still a challenging non-standardized task. Extensive research is ongoing. Updates of work in progress are presented at SAE Brake Colloquium and PMP meetings. However, open items include how to achieve lower background concentration and how to design the brake enclosure. A low background concentration is essential as brake events are short and some emit in the range of reported background levels. Hence these emissions are difficult to distinguished from the background level. Even more critical, a high background concentration can result in a wrong particle number emissions value, either overestimated, background counted as emissions, or underestimated, background level subtracted, and low emission events no longer detected and counted. However, reducing the background level to less than 100 #/cm³ appeared to be quite challenging.
In order to keep the coefficient of friction stable, some additives such as metal sulphides, are included in the brake pads formulation. Previous work from RIMSA has shown that oxidation temperature range of the metal sulphides can be one of the key properties to explain their contribution to the performance and wear of a PAD. This new work is a step forward in the interpretation of the mechanism of sulphides as chemically active additives in the brake pads. Phenolic resin is the matrix of the brake pads and starts to decompose around 300 ºC in presence of oxygen and temperature. In order to establish a connection on between sulphide oxidation and phenolic resin degradation, several studies based on heat treatment of blends of different metal sulphides (Iron sulphide, Tin sulphide and Composite sulphide) with phenolic resin have been done. Then the material evolution was studied with techniques such as TGA - DSC, XRD, IR and SEM - EDS.
In the last decade, the increasing electrification of road transports has stimulated the look for new braking systems with a high corrosion resistance. This resulted in a fervent research activity behind the development of disc brakes with a reduced corrodibility under demanding tribocorrosive environments. Despite of this, a significant reduction of the cast iron disc corrodibility can be achieved not only by developing variously coated rotors, but also by modulating the intrinsic corrodibility of iron. This can be done by and ad-hoc refining of the cast iron: a) alloying elements concentration; b) microstructure; and c) carbon content and morphology. At this regard, in this contribution, the corrosion properties of a representative ensemble of cast iron specimens are reviewed.
Raising demands towards lightweight design paired with a loss of originally predominant engine noise pose significant challenges for NVH engineers in the automotive industry. From an aeroacoustic point of view, low frequency buffeting ranks among the most frequently encountered issues. The phenomenon typically arises due to structural transmission of aerodynamic wall pressure fluctuations and/or, as indicated in this work, through rear vent excitation. A possible workflow to simulate structure-excited buffeting contains a strongly coupled vibro-acoustic model for structure and interior cavity excited by a spatial pressure distribution obtained from a CFD simulation. In the case of rear vent buffeting no validated workflow has been published yet. While approaches have been made to simulate the problem for a real-car geometry such attempts suffer from tremendous computation costs, meshing effort and lack of flexibility.
This work focuses on the effects of cooled Low Pressure EGR and Water Injection observed by conducting experimental tests consisting mainly of Spark Advance sweeps at different cooled LP-EGR and WI rates. The implications on combustion and main engine performance indexes are then analysed and modelled with a control-oriented approach, showing that combustion duration and phase and exhaust gas temperature are the main affected parameters. Results show that cooled LP-EGR and WI have similar effects, being the associated combustion speed decrease the main cause of exhaust gas temperature reduction. Experimental data is used to identify control-oriented polynomial models able to capture the effects of LP-EGR and WI on both these aspects. The limitations of LP-EGR are also explored, identifying maximum compressor volumetric flow and combustion stability as the main ones.
Duplex stainless steel (DSS) contained with dual phase such as austenite and ferrite exhibit higher strength and resistance to corrosion in numerous environmental conditions over several decades. The need of duplex stainless steel is increased gradually in the field of petrochemical, powerplant, marine and other engineering applications, where the dual phase steels are being espoused that need welding for production of components. These duplex alloys are challenging to weld due to the formation of various embrittling precipitates and variations in the metallurgy. The imbalance phase ratio of ferrite/austenite due to welding leads to solidification cracking. DSS 2205 is in need of welding with proper welding processes and consumables for corrosive environments such as shipbuilding and pipeline. In this connection, to achieve the desired requirements, austenitic filler wires (ERNiCrMo-3 and ERNiCrMo-4) are utilized for welding DSS 2205 grade using gas tungsten arc welding technique.
This research is an attempt to investigate the possibility of enhancing wear and corrosion behavior of aluminum alloy and composites for high-temperature applications. The 319 alloy with minor additions of Ni, Ti and Fe elements using the liquid metallurgy technique, Al-Si-Cu-Mg matrix alloy (Al alloy) was obtained and it was used as a base alloy and it is reinforced with Silicon carbide (SiC), Magnesium oxide (MgO) under the following composites, namely Al alloy/3wt % MgO (AA-SRM), Al alloy/ 3wt % SiC (AA-SRS) and Al alloy/3wt % SiC-3wt % MgO (AAHRSM) using stir casting route. The wear test was investigated under the following factors, namely constant sliding velocity 3.21 m/s, sliding distance up to 10000 m under different loadings (4.9, 9.8, 14.7, 19.62, and 24.5 N) using wear test by a pin on the disc test rig. The wear rate was calculated using the tested samples under different loadings, sliding distance and weight concentration conditions.
The pattern of utilizing the water/diesel emulsion fuels in engines has been given great importance due to its eco-friendly nature and minimal exhaustion of petroleum reserves. This investigation displays the impact of 1,4-dioxane emulsified fuel on performance and emissions at various operating pressures. 1,4-dioxane emulsified fuel (DWA10) was prepared with 10% 1,4-dioxane, 10% water, 0.2% surfactant and 79.8% diesel. To estimate the engine performance and emissions, the engine was operated with 180 bar, 200 bar and 220 bar operating pressures and the output was equated with diesel fuel operating on normal pressure of 200 bar. BTE of 1, 4-dioxane emulsified fuel at 220 bar was higher when compared with diesel fuel. CO, HC and BSEC were lower at 220 bar when compare with diesel fuel. However, NOx was found to increase for the higher operating pressure.
The forged connecting rod and pin experience a large amount of stresses due to cyclic load for a long period of time induced by the reciprocating movement of the piston. The proposed work focused to produce lightweight composites with high strength using waste flyash and simple manufacturing process. In this context, the proposed experimental work was formulated to develop aluminium alloy hybrid metal matrix composite of A356 alloy with silicon carbide and flyash processed through stir cum squeeze casting process under optimal parametric condition. The samples were subjected to varying flyash content of 0, 5, 10wt.% and SiC of 5wt.% kept constant. Responses like metallography, hardness, impact strength, flexural strength, fatigue strength were observed for the manufactured hybrid composites. There was a significant improvement in the properties with a higher weight percentage addition of 10wt.% flyash and 5wt.% SiC with A356 hybrid composites.
Dissimilar metal welds (DMWs), between austenitic stainless steel (ASS) and micro alloyed high strength low alloy steel (HSLA), are used in high temperature applications in power stations and petrochemical plants. The gas metal arc welding (GMAW) has surpassed the shielded metal arc welding (SMAW) process due to its advantages of producing fast, long, clean continuous weld at any position [1, 2, 3, 4, 5]. A studies on mechanical and metallurgical properties of conventional V-groove SMAW and GMA Welding of dissimilar 20 mm thick 304LN ASS and micro alloyed HSLA steel plate were carried out by using austenitic E308L- 15 electrode with gas tungsten arc welding (GTAW) root pass. The tensile (axial and all-weld) properties, hardness and microstructure of the weld and HAZ are analyzed.
The Oil Hardening Non Shrinking (OHNS) die steel refers to a variety of carbon and alloy steels that are particularly well-suited for making tools. Though these steels are weldable, there is risk of crack formation. But, this can be avoided with convinced specifications like pre heating, proper choice of electrode etc., In the present work, OHNS die steel is welded with three different electrodes. The chosen electrodes were mild steel electrode, E312-16 chromium based electrode and E-NiCrFe-3 nickel based electrode. The OHNS steel is welded with these three electrodes and the welded specimens were examined for hot cracking tendency and mechanical properties of the joint. The hot cracking tendency was assessed by Houldcroft’s weldability test (Fishbone test). All the three electrodes proved the good results in terms of hot crack resistance and the specimen welded with E312-16 chromium based electrode provides good mechanical properties.
Transportation system is at the brink of revolution and many new ways of mobility are arising in the market to ease the pressure on the established transportation infrastructure. Many companies and governments around the world are exploring innovative options in the space of shared mobility to reduce the overall carbon footprint. To expedite the adoption of shared mobility in India, it is necessary to make such options comfortable and cost-effective. One of the most effective way to make shared mobility options cost effective is to comfortably increase occupancy per vehicle footprint. This paper aims to evaluate a novel method of occupant seating to identify the maximum number of passengers a vehicle can accommodate without significant impact on occupant comfort. It is assumed that shared mobility options are used for a short duration of commute, and hence the comfort of the seat can be marginally compromised to increase the total number of occupants.
Sealing is one of the important components in the automotive and aerospace industry. The primary function of the lip seal is to protect contamination and retaining the lubricant. This investigation relates to a study of contact pressure existence on sealing structure between there mating region. Sealing for steering intermediate shaft should sustain sliding motion between shaft and seal as well as protection of lubricant from contamination and retention. Contact pressure analysis of Steering intermediate shaft with hyper elastic rubber seal is done at static condition using ABAQUS. Experiments were also conducted to check contact pressure between seal and shaft by using Fuji-pressure film sensor. The result from CAE analysis was compared with experimental data with 75% of the correlation with respect to CAE. This analysis of contact pressure helps to support on giving enough interference between seal and shaft which satisfies the need of sealing for an intermediate shaft.
In these work AZ91 magnesium matrix composites reinforced with two weight fractions (5 and 10 wt. %) of TiB2 particulates were fabricated by cold chamber die casting process technique. The microstructure, density, hardness, mechanical properties of the specimens was investigated. Microstructure studies showed that fairly uniform distribution of reinforcements was achieved up to the weight fraction studied. As compared to base alloy AZ91, the hardness and tensile strength considerably increased with increasing reinforcement content. The presence of TiB2 particles improved the hardness around 24.4 %, compressive strength around 67.2% and the yield strength around 20%. The enormous amount of increment in the compressive strength due to the dislocation density created by the difference in thermal properties of matrix and composites and also due to the micro-pores presence in the composite.