Refine Your Search

Topic

Author

Affiliation

Search Results

Technical Paper

Wall Heat Flux on Impinging Diesel Spray Flame: Effect of Hole Size and Rail Pressure under Similar Injection Rate Condition

2020-10-30
2020-32-2313
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.
Technical Paper

Improvement of Fuel Consumption for SI Engines by Combing with Glow Plug Heated Sub-chamber and Lean Burn

2020-10-30
2020-32-2310
Lean burn gasoline engines can achieve noteworthy fuel consumption and power output. However, when the mixture becomes lean, the ignition delay increases, and the flame propagation speed becomes slow, which lead to increase the combustion fluctuation. The glow plug is usually used to solve the cold start problem in diesel engines, where the compression temperature might not be high enough to ensure the proper ignition of the injected fuel, resulting in instability combustion and increased exhaust emissions. Based on this point, the present study intends to install a glow plug to the sub-chamber. Experiments were conducted on a modified single cylinder four-stroke CI engine (YANMAR TF120V) to operate as SI engine with a higher compression ratio compared to the conventional SI engines, 15.1:1. The engine is operated at a constant speed of 1000 rpm for different equivalence ratios with different voltage of glow plug which creates the temperature variation inside the sub-chamber.
Technical Paper

Investigations on NOx and Smoke Emissions Reduction Potential through Diesel-Water Emulsion and Water Fumigation in a Small Bore Diesel Engine

2020-10-30
2020-32-2312
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.
Technical Paper

A Concept Investigation Simulation Model on Hybrid Powertrains for Handheld Tools

2020-10-30
2020-32-2316
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.
Technical Paper

Enclosure-In-Chamber Setup to Achieve Near-Zero Background Concentrations for Brake Emissions Testing

2020-10-05
2020-01-1634
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.
Technical Paper

A Generic Testbody for Low-Frequency Aeroacoustic Buffeting

2020-09-30
2020-01-1515
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.
Technical Paper

Determination of energy-saving potentials by reducing the rolling bearing friction in the tractor drive train

2020-09-27
2020-24-0024
Increased efficiency and emission reduction have, in recent years, introduced several changes in the architecture of agricultural tractors transmissions. As one of the leading rolling bearing manufacturers for this industry, Schaeffler has explored energy saving potentials related to rolling bearings friction reduction. Starting point of the activity is the actual status of the design of tractor transmission manufactured by one of the key players in the sector.
Technical Paper

Experimental Investigation on the Effects of Cooled Low Pressure EGR and Water Injection on Combustion of a Turbocharged GDI Engine

2020-09-27
2020-24-0003
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.
Technical Paper

Development and Experimental Validation of a Control-Oriented Empirical Exhaust Gas Temperature Model

2020-09-27
2020-24-0008
Modern turbo-charged downsized engines reach high values of specific power, causing a significant increase of the exhaust gas temperature. Such parameter plays a key role in the overall powertrain environmental impact because it strongly affects both the catalyst efficiency and the turbine durability. In fact, common techniques to properly manage the turbine inlet gas temperature are based on mixture enrichment, which causes both a steep increase in specific fuel consumption and a decrease of catalyst efficiency. At the test bench, exhaust gas temperature is typically measured using thermocouples that are not available for on-board application, and such information is processed to calibrate open-loop look-up-tables. A real-time, reliable, and accurate exhaust temperature model would then represent a strategic tool for improving the performance of the engine control system.
Technical Paper

Performance Evaluation of Extended-Range Electric Vehicles equipped with Hydrogen-Fueled Rotary Engine

2020-09-27
2020-24-0011
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.
Technical Paper

Turbulent jet ignition Effect on Exhaust Emission and Efficiency of a SI Small Engine Fuelled with Methane and Gasoline

2020-09-27
2020-24-0013
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.
Technical Paper

Retrofit of a Heavy-Duty Diesel Truck: Comparison of Parallel and Series Hybrid Architectures with Waste Heat Recovery

2020-09-27
2020-24-0015
This paper describes and compares different powertrain configurations for the retrofit of a heavy-duty Class 8 truck, powered by a 12.6 liters diesel engine. The engine is firstly equipped with an electrification-oriented organic Rankine cycle (ORC) system and then coupled to a traction electric machine into a hybrid powertrain. An electrification-oriented ORC system can produce enough energy to cover the ancillary loads, which in long-haul applications for freight transportation are quite demanding. Nevertheless, only powertrain hybridization can achieve significant improvements in the overall system efficiency. Both systems may thus be implemented in the same vehicle, but an efficiency improvement is guaranteed only if the system is carefully managed so as to reach a trade-off between the requirements and potential benefits of the ORC system and those of the hybrid powertrain.
Technical Paper

SCiNaS: A Smart City-driven Navigation System to Catch Green Waves

2020-09-27
2020-24-0017
Driving in modern cities is getting harder and harder due to the continuously changing road and traffic conditions, binding to navigation systems for successful route planning. Despite navigators are becoming more and more powerful and precise in estimating road and traffic conditions, there is still room for improving their effectiveness in route planning. On the other hand, urban areas, thanks to Information and Communication Technologies, are becoming smarter and smarter, enough to be termed as smart cities since they are able to provide advanced smart services, among which mobility ones. The context of this paper is the integration of such two systems and technologies, merging smart navigation solutions and smart city services to obtain value added services improving route planning effectiveness by achieving a trade-off between the two. To this purpose, a smart navigation system that actively interacts with the smart city infrastructure facilities for route planning is developed.
Technical Paper

Engine knock evaluation using a machine learning approach

2020-09-27
2020-24-0005
Artificial Intelligence is becoming very important and useful in several scientific fields. Machine learning methods, such as neural networks and decision trees, are often proposed in applications for internal combustion engines as virtual sensors, faults diagnosis systems and engine performance optimization. The high pressure of the intake air coupled with the demand of lean conditions, in order to reduce emissions, have often close relationship with the knock events. Fuels autoignition characteristics and flame front speed have a significant impact on knock phenomenon and producing high internal cylinder pressures and engine faults. The limitations in using pressure sensors in the racing field and the challenge to reduce the costs of commercial cars, push the replacement of a sensor redundancy with a software redundancy.
Technical Paper

Experimental and Numerical Investigations of Hydrogen Enriched Turbocharged Diesel Engine

2020-09-25
2020-28-0472
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.
Technical Paper

Design and Analysis of a Supercharged Cross Breed Engine

2020-09-25
2020-28-0447
This investigation is based on the development of internal combustion engine and focusing on retaining the two-stroke cycle engine with sophisticated technologies. Due to stringent emission norms, faster depletion of petroleum fuels, fuel economy this modification is suggested based on the critical analysis. The development of a supercharged cross breed engine will be a next milestone in automotive fields, which will enhance the upcoming I.C. engines to work under effective efficiency without any deviations from the actual working cycle. The design and simulation have been carried to out to reduce or eliminate the losses during operation. Also,both the power and emission characteristics of a engine were balanced and improved than the conventional engines.
Technical Paper

Improving the Fuel Economy of Truck by Reducing Aerodynamics Drag - 3D CFD Study

2020-09-25
2020-28-0383
The present numerical analysis aims at studying the effect of changes in profile of truck-trailer on aerodynamic drag and its adverse effect on fuel consumption. The numerical analysis is carried out using commercial CFD software, ANSYS Fluent, with k-ω Shear tress transportation (SST) turbulence model. In present study four models of truck were analysed, including baseline model at different Reynolds numbers, namely 0.5, 1, 1.5 and 2 million. In order to enhance fuel consumption, various profile modifications have been adapted on baseline truck-trailer model by adding a spoiler and bottom diffuser at the rear of the truck, by providing vortex generator at the rear top of the truck and by adding boat tail at the end of trailer. The comparison has been done with respect to coefficient of drag, coefficient of pressure, pressure contours, and velocity vectors between all four cases.
Technical Paper

Optimization of the Bearing Oil Supply Concept of a High Power-Density Diesel Engine to Minimize Oil Pump Friction

2020-09-25
2020-28-0338
Reducing the mechanical friction of internal combustion engines could play a major role in improving the brake specific fuel consumption (BSFC). Hence, it is important to reduce the friction at every component and sub-system level. In the present work, the oil pump friction of a 1.5 liter 4-cylinder diesel engine is optimized by reducing the oil pump displacement volume by 20%. This could be achieved by adopting an optimized oil supply concept which could reduce the oil leakage through the main bearings and connecting rod bearings. A 1-dimensional oil flow simulation was carried out to predict the oil flow distribution across the engine for different speeds. The results indicate that the oil leakage through the main bearings and connecting rod bearings contribute to ~25% of the total oil flow requirement of the engine. In a conventional oil supply concept, the big-end bearing of each connecting rod is connected to the adjacent main bearing through an internal oil hole.
Technical Paper

Selection of Different Strategies of Exhaust Gas Thermal Management for Optimum Fuel Economy

2020-09-25
2020-28-0339
To tackle the problem arising due to emissions and to reduce them, complex after-treatment system is used. For efficient working of the after-treatment system it must operate at enough high temperature even at low loads for better conversion efficiency. Also, there is different temperature requirements for different catalyst used in SCR (Selective catalyst reduction) system. For this, various on engine strategies are implemented on modern diesel engines such as multiple fuel injection, late fuel injection, high fuel injection pressure and exhaust gas recirculation. Thermal management of exhaust gasses is an operating condition which must be triggered when there is need of elevated temperatures for efficient functioning of the after-treatment system. Thermal management includes SCR thermal management and regeneration.
Technical Paper

Experimental and Numerical Investigation of Contact Pressure Existence in Sealing Structure

2020-09-25
2020-28-0343
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.
X