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.
This study examined the effects of storing gasoline (E0) and low level ethanol blends (E10, E15, E20) in small engines over a 12 month period. Many variables were monitored or controlled in order to determine if ethanol blended fuels affected small engines during storage. A sample size of 64 engines was used to reduce the effects of normal engine to engine performance variations and analyze trends with the different fuel blends. For the study, 32 handheld 2-stroke engines with a cube carburetor (leaf blowers) and 32 non-handheld 4-stroke consumer grade small engines with a float carburetor (gensets) were tested. These engines were selected to represent many different types of equipment on the market and for ease of loading during the study. The engines were measured after initial purchase, after 6 months of storage, and after 12 months of storage to check for changes.
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.
The combustion and emission formation in the advanced low temperature combustion (LTC) engine strategies are highly sensitive to fuel molecular composition and properties. Ignition timing in LTC is primarily controlled by fuel chemical kinetics and thus, tailoring of fuel properties is required to address its limitations in-terms of lack of control on ignition timing and narrow operating load range. Utilizing fuel blends and additives such as nanoparticles are one of the promising approaches to achieve targeted fuel property. An improved understanding of fundamental processes including fuel evaporation is required owing to its role in fuel-air mixing and thereby emission formation in LTC. In the present work, evaporation characteristics of blends of commercial fuels, viz. gasoline, diesel and alternative fuels, viz. ethanol and butanol are investigated. Further, graphene based nanoadditives at 0.05 wt % in gasoline, diesel and butanol are also investigated.
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.
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.
In order to mitigate the effect of fossil fuels on global warming, biodiesel is used as drop in fuel. However, in the mixture of biodiesel and diesel, soft particles may form. These soft particles are organic compounds, which can originate from the production and degradation of biodiesel. Further when fuel is mixed with unwanted contaminants such as engine oil the amount soft particles can increases. The presence of these particles can cause malfunction in the fuel system of the engine, such as nozzle fouling, internal diesel injector deposits (IDID) or fuel filter plugging. Soft particles and the mechanism of their formation is curtail to understand in order to study and prevent their effects on the fuel system. This paper focuses on one type of soft particles, which are metal soaps. More precisely on the role of the short chain fatty acids (SCFA) during their formation. In order to do so, aged and unaged B10 and B100 were studied.
The growing need for a sustainable worldwide mobility is leading towards a paradigm shift in the automotive industry. The increasingly restrictive regulations on vehicle emissions are indeed driving all of the world-leading road vehicles manufacturers to redesign the concept of transportation by developing new propulsion solutions. To this aim, a gradual electrification strategy is being adopted, and several hybrid electric solutions, such as extended-range electric vehicles with reciprocating engines or fuel cells, already represent a valid alternative to conventional vehicles powered by fossil fuels. Despite their appealing features, these hybrid propulsion systems present some drawbacks, mainly related to their complex architecture, causing high overall dimensions, weight and costs, which pose some limitation in their use for small-size vehicles.
Pollutant emission of vehicle cars is nowadays a fundamental aspect to take into account. In the last decays, the company have been forced to study new solutions, such as alternative fuel and learn burn mixture strategy, to reduce the vehicle’s pollutants below the limits imposed by emission regulations. Pre-chamber ignition system presents potential reductions in emission levels and fuel consumption, operating with lean burn mixtures and alternative fuels. The aim of this work is to study the evolution of the plasma jets in a different in-cylinder conditions. The activity was carried out in a research optical small spark ignition (SI) engine equipped alternatively with standard ignition system and per-chamber. The engine runs at 2000 rpm at wide open throttle (WOT) in standard ignition condition and slightly turbocharged in prechamber condition in order to overcame the decrease of compression ratio. In this activity methane and gasoline were used.
Hydrogen is the most promising alternate fuel for Internal Combustion engines whereas its potential for Compression Ignition (CI) engine is unexplored. The addition of hydrogen to conventional hydrocarbon fuels is the best method to improve performance and emission of internal combustion engine. The present work aims to evaluate the effect of partial replacement of diesel with hydrogen in CI engine by means of hydrogen enrichment. Enrichment is achievedby introducing hydrogen with the intake air stream in intake manifold. The test engine used is 4-cylinder, water cooled 3.24L turbocharged diesel engine. Enrichment is achieved by retrofitting the hydrogen induction system in intake manifold. The hydrogen is continuously injected using mechanical injector associated with all safety equipment. The diesel and hydrogen mass flow rates are controlled to vary enrichment percentages from 2% to 8%. Also numerical base line engine model and hydrogen enriched model is developed in AVL Boost.
The search for a new renewable biofuel and aiming to make the environment clean is always a challenge for a researcher in developing a sustainable fuel for future mobility. In this context, vegetable oils are found as good alternative biofuels for diesel engines as they are biodegradable and renewable in nature. Most of the physio-chemical properties of vegetable oils are very closer to diesel. However, pure vegetable oils are expensive and using them to operate the diesel engine may affect the food supply chain. In view of this limitation, Waste Cooking Oil Methyl Ester (WCOME) derived from waste cooking oil is found to be very attractive solution for the above said constraints as they are easily available, renewable, economically and environmentally viable. This research aims at studying the effect of hybrid nano additives (i.e. Copper Oxide with Zinc Oxide) on performance and emission characteristics of a diesel engine fueled with Waste Cooking Oil Methyl Ester.
This work explores the influence of ethanol on improving engine's behavior of Waste Cooking oil (WCO) based dual fuel diesel engine. A single cylinder diesel engine was tested in dual fuel mode of operation at the maximum rated power output of 3.54 kW. In the current study a diesel engine is made to run using ethanol in dual fuel mode with diesel, where ethanol is introduced as primary fuel into the intake manifold and WCO as pilot fuel. The ethanol energy contents of the total fuel were varied from 5%, 10%, 15%, 20%,25%,30%,35% and 40% were experienced at (1500 ± 10) rpm of constant engine speed The test results showed the improvement in brake thermal efficiency (BTE) of the engine, reduction in brake specific fuel consumption (BSFC) with an increasing ethanol energy fraction. Furthermore, indicated specific NOx, CO, CO2 and smoke emissions decrease with an increasing percentage of ethanol energy content.
The current research work concentrate on the use of nano additive as a distinguishable thing for decelerating hazardous diesel engine emissions. The experiment was conducted with biofuel; there is no significance of engine modifications for using the biofuel. The surplus amount of oxygen integrated within the biofuel can able to generate higher combustion rate relatively it produces more NOx, the NOx burden can be reduced with the help of REGR (reformed exhaust gas recirculation). The reforming of exhaust gases causes the measurable generation of smoke, CO and HC. In order to reduce the formation of above emissions, the affordable and sustainable alternate identified from the present research, by citronella biofuel with 100ppm Cobalt Chromite nano additive. The scrutinized output enumerates that the substantial reduction in HC, CO, and BSFC with elevated EGT (exhaust gas temperature) achieved by CBN-REGR than the typical usage of the traditional CB-REGR system.
The rapid deficiency of fossil fuel resources encourages the research community to discover the sustainable alternate fuel, in order to overcome the fuel cost and also meet the stringent emission norms. In this connection, the current investigation explores the influence of cobalt chromate with significant potential of citronella biofuel for CI engine applications. In present investigation, the synthesized cobalt chromate nano additive blended with citronella biofuel with the help of magnetic stirrer and ultrasonication for a period of 15 to 20 minutes on a volume basis. In this experimentation, various blend contractions are prepared as follows as 50ppm, 100ppm, and 150ppm to run the engine. The outcome results explore that the 100ppm cobalt chromate dispersion in biofuel has a significant increase in brake thermal efficiency as 3.21% than raw citronella biofuel.
The present work focuses on the processing and characterization of LPG cylinder made up of glass fibre reinforced composite (GFRC) material. The commercial steel LPG cylinder is difficult to handle due to more weight and easily corroded with moisture environment. To overcome this problem, composite material which has high specific stiffness, high specific strength, less weight and high corrosion resistance to moisture is used to fabricate the LPG cylinder. In this investigation, the LPG cylinder with dimensions of commercial 5 kg Steel LPG cylinder is made by filament winding technique. While fabricating, the fibres are wounded on the plastic inner container which is used as gas-tight in-liner. The specimens are prepared from the fabricated composite LPG cylinder. The material properties of composite materials are evaluated by the tensile test, compression test, flexural test, density test and impact test.
Compression-Ignition engines are widely used for irrigation purposes in rural areas, which produce more noise and vibrations. In this research, neat diesel and Pongamia biodiesel blend (B20) was used to study combustion, noise, and vibration characteristics of an unmodified Genset compression ignition engine. Investigations were carried out in various load conditions from no load to full load. From the experimental results, it has been found that a strong correlation exists between the heat release rate and engine noise. The heat release rate is directly proportional to the magnitude of the engine noise. The noise level has an increasing trend for diesel and a decreasing trend for biodiesel with an increase in load conditions. A maximum of 80.3dB and 78.3dB was observed at 60% loading conditions for diesel and biodiesel, respectively.
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.