Fuel economy is becoming one of the key parameter as it not only accounts for the profitability of commercial vehicle owner but also has impact on environment. Fuel economy gets affected from several parameters of engine such as Peak firing pressure, reduction in parasitic losses, improved volumetric efficiency, improved thermal efficiency etc. Compression ratio is one of key design criteria which affects most of the above mentioned parameters, which not only improve fuel efficiency but also results in improvement of emission levels. This paper evaluates the optimization of Compression ratio and study its effect on Engine performance. The parameters investigated in this paper include; combustion bowl volume in Piston and Cylinder head gasket thickness as these are major contributing factors affecting clearance volume and in turn the compression ratio of engine. Based on the calculation results, an optimum Compression Ratio for the engine is selected.
Accumulation of ash in the Diesel Particulate Filter (DPF) with engine operating over the time is a major concern for all vehicle manufacturers, with BS VI and BS VII emission norms mandating the use of DPF. Ash deposition leads to increase in pressure drop across the filter and more frequent regeneration pattern, which can lead to sintering. It can hamper the capacity of soot loading, properties of DPF substrate material and can lower catalyst activity in case of Catalysed-DPF. Hence, removal of ash is important by defining the DPF cleaning methods. Primary source of ash is lubricant oil, taking part in the combustion. Lubricant additives like detergents and anti-wear agents are responsible for formation of metallic ash inside the DPF. Secondary source of metallic ash is fuel and engine wear out. The present paper elucidates the preparation of DPF samples including coating and canning of DPF substrates, with proper GBD.
Engine up gradation for higher power rating involves challenges that require hardware changes which not only increase cost but also demand higher space. This paper focuses on the up gradation of a 4 cylinder 4.9l CRDi engine from 24.03 kW/L to 30.75 kW/L by adjustment of various parameters to meet both emission and performance targets. Various challenges like higher exhaust temperature, increased peak firing pressure etc. were met using the proper calibration strategy. To meet SFC targets and keep peak firing pressures, exhaust temperatures within desired limits, different operating points for EGR, main injection timing, rail pressure have been optimized. The operating points for optimization were determined by conducting various drive trials on different type of load conditions in test bench. Calibration strategy involved the safe limits of NOx, soot, CO emissions, fuel consumption.pfp, and exhaust temperature.
Hydrogen has low ignition energy ensures easy ignition of the ultra-lean mixture of H2+air also. The flame speed of hydrogen is about five times higher than methane and gasoline which allows hydrogen fuelled IC engines to have relatively reduced cyclic variations than that of with methane and gasoline. High flame speed also helps to make the combustion closer to constant volume which enhances the thermal efficiency of hydrogen fuelled IC engine. High octane number of hydrogen makes it suitable for its application in Spark ignition (SI) engines. Since the hydrogen combustion in spark ignition engine generates water which can interfere with the lubricant performance, different lubricant is to be developed for this purpose. In this background, the present work is aimed at the development of dedicated lubricant for hydrogen fuelled SI engine. This paper presents the various parameters required for evaluating different lubricants for hydrogen fuelled genset.
The design optimization and control of Free Piston Linear Engine (FPLE) has been found to be difficult as each independent variable changes the dynamics with respect to time. These dynamics, in turn, alters the alternator and engine response to other governing variables. As a result, the FPLE system necessitates an energy balance control algorithm with high-speed dynamic response for stable operation and perhaps optimized system efficiency. The main objective of this control algorithm is to match the power generated by the engine to the power demanded by the alternator. This energy balance control is similar to the use of a governor to control the crankshaft rotational speed in a conventional crankshaft driven engine. In addition to that, when stiff springs are added to the FPLE system, the dynamics becomes more sinusoidal and more consistent with increasing spring stiffness.
In automobile car body door engineering, fitting a styling surface of side door glass to the cylinder or torus is the basic requirement. Optimization is required to approximate the class A side door glass surface to cylindrical or toroidal surface. This optimization process requires a solver which could be efficacious for best surface fitting. This paper propounds a methodology which could be used for fitting a styling surface of side door glass to the cylinder or torus. The method will significantly help in developing the required surface and would successfully obsolete the onerous manual calibrations. The mathematical model mentioned is a novel approach based on “Particle Swarm Optimization” towards surface optimization technique. VB script is used to make it applicable in CATIA but could be easily applied in python, java etc.
Keywords - Four valve intake port design, steady flow test, CFD numerical simulation, off-highway engines Abstract: Future emission limits for off-highway application engines need advanced power train solutions to meet stringent emissions legislation, whilst meeting customer requirements and minimising engineering costs. Development of diesel engines for off-highway application for different power segments need different intake port design solutions to optimise in-cylinder flow structure for efficient combustion. With adaptation of low pressure mechanical fuel injection system, intake port development becomes an important stage for reduction of emission formation at the source and improvement in fuel economy. In this paper, intake port design and development process is elaborated for two different power ratings of 75 hp and 120 hp of off-highway engine. 2-valve and 4-valve configurations are deployed for the same cylinder bore size.
This paper describes the design of a novel pneumatic gear shifting system to replace the existing gear stick manual shifting system for ease of the driver while shifting gears. The aim of this work is to have a semi-automatic shifting(pneumatic shifting) removing the need for the driver clutch operation. The system consists of a solenoid valve, CO2 gas pressurized cylinder, double acting cylinder, and single acting cylinder. On basis of the signal received the gear needs to be changed, the shifter opens or closes a magnetic valve assembly. The solenoid valve allows the compressed air into the piston that comes from a pressurized cylinder, in order to create the effect of shifting gears. Pedal shifter and buttons are used to shift the gears. The pedal shifter was designed by using a 3-D printing technique using PLA material. The microcontroller used is ATMEGA-328 in this system. There are three switches, one for upshift, downshift, and clutch respectively.
In lieu of the increase in the population of automobiles, there is heavy use of fossil fuels and mineral oils. This leads to depletion in fossil fuel and mineral oil which is a by-product of petroleum. We cannot depend on this for a long period of time and which is toxic to the environment. In order to reduce the usage of existing mineral oil for lubrication, a source of non-edible oil from Jatropha Curcus which is available in an abundant and renewable source of alternative lubricant is processed as jatropha methyl ester because of high viscosity and density and blended with base oil which reduces the pollution. To increase the antiwear properties of the lubricating oil nano copper oxide particle additive are blend with the base oil which is tested in a two-stroke engine. Emission and tribological effects have been tested. There are chances of them being depleted in a short span of years.
The present work compares the tribological properties of ZnO nanoparticle based lubricant with ZDDP (zinc dialkyl dithiophosphate) based lubricant. The nanolubricant was prepared by mixing the nanoparticles in base oil followed by ultrasonification and ZDDP based lubricant was prepared by mixing ZDDP and stirring with base oil. Base oil used was mineral base oil. Both the lubricants were tested at three different temperatures, loads and roughness values. The test was carried out on AISI 52100 steel samples prepared by wire cutting and were grinded to three different levels of surface roughness. Friction and wear tests were performed using a reciprocating sliding tribo-tester at three different loads and temperatures. Taguchi orthogonal array was used to reduce the number of experiments. SEM, EDS and AFM analysis were carried out to study the surface wear phenomenon.
Improvement of performance and emission of future internal combustion engine for passenger cars is mandatory during the transition period toward their substitution with electric propulsion systems. In middle time, direct injection spark ignition (DISI) engines could offer a good compromise between fuel economy and exhaust emissions. However, abnormal combustion and particularly knock and super-knock are some of the most important obstacles to the improvement of SI engines efficiency. Although knock has been studied for many years and its basic characteristics are clear, phenomena involved in its occurrence are very complex and are still worth of investigation. In particular, the definition of an absolute knock intensity and the precise determination of the knock onset are arduous and many index and methodologies has been proposed. In this work, most used methods for knock onset detection from in-cylinder pressure analyses have been considered.
This work aims to expand the applicability of an open-source numerical tool to solve hypersonic gas dynamic flows for space propulsion geometries. This is done by validating the code using two well-known hypersonic test cases, the double cone and the hollow cylinder flare, used by the NATO Research and Technology Organization for the validation of hypersonic flight for laminar viscous-inviscid interactions (D. Knight, "RTO WG 10 - Test cases for CFD validation of hypersonic flight," in 40th AIAA Aerospace Sciences Meeting & Exhibit, 2002). The Computational Fluid Dynamic (CFD) simulation is conducted using the two-temperature solver hy2Foam that is capable to study external aerodynamics in re-entry flows. In the present work the assessment of hy2Foam to solve hypersonic complex flow features with strong interactions including non-equilibrium effects was demonstrated.
In-cylinder combustion state is assumed as homogeneous with steady physical properties of working gas for the ideal thermal efficiency calculation, whereas that for an actual diesel engine (diffusion combustion) is much heterogeneous by complexed temperature and gas composition distribution resulting in the lower specific heat ratio. The goal of this study is to improve thermal efficiency by keeping specific heat ratio higher in the burned zone, which could be achieved with better air entrained and highly dispersed flame in the cylinder.
The paper reviews the CFD optimization of a motorcycle engine, modified for the installation in a hybrid powertrain of a Formula SAE car. In a parallel paper [Development of a hybrid power unit for Formula SAE application: packaging optimization and thermo-mechanical design of the electric motor case], the choice of the donor engine (Ducati 959 “Panigale”) is thoroughly discussed, along with all the hardware modifications oriented to minimize the new powertrain dimensions, weight and cost, and guarantee the mechanical reliability. In the current paper, the attention is focused on two main topics: 1) CFD-1D tuning of the modified Internal Combustion Engine (ICE), in order to comply with the Formula SAE regulations, as well as to maximize the power output; 2) Simulation of the vehicle in racing conditions, comparison between a conventional and a hybrid powertrain
The potentiality of knock mitigation by means of the control of the coolant flow rate is investigated. As a first step, the dynamic behavior of the wall temperature in response to a sudden variation of the coolant flow rate is analyzed experimentally in a small displacement, 4-valve per cylinder SI engine, which is equipped with an electrically driven pump. Subsequently, the influence of the wall temperature on knock onset is analyzed through a zero-dimensional model and the Livengood and Wu integral. Finally, an experimental activity on the engine test bed is carried-out in order to evaluate the influence of the coolant flow rate and of the engine inlet coolant temperature on the knock phenomenon. Results show that, even though a retarded spark advance and a mixture enrichment are not avoidable in the early stage of knock onset, a cooling control can help reducing the time of use of these fuel consuming strategies in the case of prolonged high-load conditions.
The conversion of existing diesel engines to natural gas operation can reduce U.S. dependence on petroleum imports and curtail engine-out emissions. Diesel compression ignition engines can be modified to NG spark ignition, by replacing the diesel injector with a NG spark plug and by fumigating NG in the intake manifold, to increase utilization of natural gas heavy-duty transportation sector. As the original diesel piston is maintained during conversion to decrease engine modification cost, the major of this study was to investigate the lean-burn characteristic of natural gas burning in this bowl-in-piston combustion chamber, which can accelerate the introduction of heavy-duty natural gas vehicles. Data analysis from engine experiments that changed spark timing indicated a two-stage combustion process in such retrofitted engines, which is different from traditional spark ignition engines.