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.
Amid the increasing demand for higher efficiency in combustion driven handheld tools, the recent developments in electric machine technology together with the already existing benefits of small combustion engines for these applications favor the investigation of potential advantages in hybrid powertrain tools. This concept-design study aims to use a fully parametric, system-level simulation model with exchangeable blocks, created with a power-loss approach in Matlab and Simulink, in order to examine the potential of different hybrid configurations for different tool load cycles. After the model introduction, the results of numerous simulations for 36 to 100 cc engine displacement will be presented and compared in terms of overall system efficiency and overall powertrain size. The different optimum hybrid configurations can show a reduction of up to 30 % in system’s brake specific fuel consumption compared to the baseline combustion engine driven model.
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.
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.
Psychoacoustics parameters are widely employed in automotive field for objective evaluation of Sound Quality of vehicle cabins and their components. The standard approach relies on binaural recordings from which numerical values and curves are calculated and head-locked binaural listening playback can be performed. Recently, the Virtual Reality technology started to diffuse also in automotive field, bringing new possibilities for enhanced and immersive listening sessions. In this paper, we combine both solutions: the VR approach is adopted to calculate the principal psychoacoustics parameters. The acquisition system consists in a massive spherical microphone array featuring a camera for recording panoramic visual background. The acoustical information is encoded into High Order Ambisonics spatial format, that can be rendered on stereoscopic visors and Spatial PCM Sampling format that can be used to produce 360° colour maps.
Some hybrid powertrains utilize an engine to benefit from the power density of the liquid fuel while the electric machine; for transient needs, for very low loads and where legislation prohibits any gaseous and particulate emissions. Consequently, the operating drive cycle of an engine also shifted from its conventional, broad range of speed and load to a narrower operating range of high thermal efficiency. This requires a drastic departure from conventional engine architecture, meaning that analytical models used to predict the behaviour of the engines early in the design cycle are no longer always applicable. Friction models are an example of sub-models which struggle with previously unexplored engine architectures. The pressurized motored method has proven to be a simple experimental setup which allows a robust FMEP determination against which engine friction simulation can be fine-tuned.
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.
The SAE organization constrained a rule to place a restrictor of diameter 20mm in between the throttle body and the engine inlet . The restrictor is an component which reduces and regulates the mass flow of air into the engine inlet. For this a venture nozzle will be used as a restrictor in vehicle to decrease the air pressure and increase the velocity in the intake manifold . The aim of our proposed work is to minimize the pressure drop by changing the convergent and divergent angles in the restrictor. For this by using solidworks sixteen various models with convergent angle as 11,13,15,17 degrees and divergent angle as 3,5,7,9 degrees was designed and analysed using CFD fluent in ansys work bench. In this 13 degree as convergent and 5 degree as divergent model was found to have laminar air flow through out with optimum pressure drop. The plenum is a large duct which equalise the pressure drop caused by restrictor in order to improve the efficiency of engine.
Environmental Control System (ECS) of an aircraft is a complex system which operates classically in an air standard refrigeration cycle. ECS controls the temperature, pressure and flow of supply air to the cockpit, cabin or occupied compartments. The air cycle system of ECS takes engine bleed air as input. Parameters like bleed air pressure and temperature, mass flow, the external factors like ambient temperature, pressure, and aircraft attitude affect the performance of ECS to a large extent especially during transient. So, it is very important to consider the transient characteristics of these parameters in the design stage itself in order to ascertain the dynamic response of the system. This paper explains in detail the importance of transient input characteristics during the detailed design of ECS. A typical temperature control scheme for combat aircraft ECS has been studied and modeled in LMS AMESim.
The usage of AZ91E series magnesium alloy material increases in the field of automobile, aero space and structural applications because of its enhanced mechanical properties, light weight and good machinability characteristics. The present investigation is to optimize the drilling process parameters of magnesium alloy (AZ91E) hybrid nano composite consisting of chopped basalt fiber (9wt%) and SiCnp(7.5wt%) fabricated by vacuum stirring technique.. AZ91E hybrid nano composite is drilled by M-Tab vertical machining centre equipped with CNC under dry state (without coolant). The dry state drilling operation was performed by HSS tool with varied input parameters like drill diameter (4mm, 6mm, 8mm and 10mm), drill diameter prevailing with spindle speed, feed rate and constant depth of cut. The effect of machining time, metal removal rate and surface roughness is evaluated and optimum level of drilling parameters is determined through taguchi technique.
The economic growth of the company depends on the quality and delivery time of the components. The pursuit of new techniques is mandatory to maintain quick delivery time without compromising quality. Ergonomics is one such technique that helps to improve workstation productivity by reorganizing the workspace, changing the sequence in operations, up-gradation of machine tools, reducing operator fatigue, etc. The ergonomic study was performed in a tractor steering gearbox manufacturing unit. In the present work,an ergonomic assessment of the workstation is done. Ergonomics assessment includes Rula assessment and Work-place assessment helped to find out the factors influencing the work station to be in alert zone.During the observation of base milling operation the operator need to clamp and de-clamp the steering box manually by using mechanical tools.
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 government 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 based travelling options in India, it is necessary to make such options comfortable and cost-effective. To make the mobility option cost-effective, it is important to comfortably allow as many passengers per vehicle foot-print as possible. This paper aims to evaluate a novel method of occupant seating to maximize the number of passages the vehicle cabin can accommodate. Since shared mobility options are used for a short duration of commute, the comfort of the seat can be compromised for increasing the no. of occupants. This paper studies the relation between occupant comfort and the inclination of seat cushion.
Sealing is one of the important components in automotive and aerospace industry. The primary function of lip seal is to protect contamination and retaining the lubricant. This investigation relates to study of contact pressure existence on dynamic sealing. Sealing for steering intermediate shaft requires 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 as well as sliding 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. This analysis of contact pressure helps to support enough interference between seal and shaft with satisfies the need of sealing as well as sliding in intermediate shaft.
Automotive manufacturers are constantly working towards enhancing the driving experience of the customers. In this context, improving the static and dynamic gear shift quality plays a major role in ensuring a pleasant and comfortable driving experience. Moreover, the gear shift quality of any manual transmission is mainly defined by the design of the synchronizer system. In the present work, the static and dynamic shift quality of a 300 Nm manual transmission is analyzed with different synchronizer sleeve strut detent profiles. The synchronizer sleeve strut detent groove profile play a vital role in defining the performance of the synchronizer system by generating the minimum required pre-synchronization force. This force is important to move the outer synchronizer ring (blocker ring) to the required index position and to wipe-out the oil from the conical friction surfaces to build rapid high cone torque.
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.