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Chennai, India

Suresh Kumar J.,Indian Institute of Technology Madras | Ganesan V.,Indian Institute of Technology Madras | Mallikarjuna J.M.,Indian Institute of Technology Madras | Govindarajan S.,UCAL Fuel Systems Ltd
Indian Journal of Engineering and Materials Sciences | Year: 2013

Throttle body assembly plays a vital role in metering the airflow. It mainly consists of a butterfly valve to vary the flow area to control air flow rate through it. There is hardy any established procedure to design a throttle body assembly based on the engine specifications. In order to bridge the gap, this study, design and optimization of a throttle body assembly for a single-cylinder engine used in two-wheeler application has been analyzed along with the investigation of critical flow through various sub systems using computational fluid dynamics (CFD). To start with, the throttle bore and bypass passage diameters are calculated from the basic flow equations. Using CFD, best possible throttle shaft profile is arrived at, which will enhance airflow to the engine. The airflow rate for different throttle openings is predicted taking into account the distribution of main and bypass flow. It is observed that the airflow through main and the bypass passage are almost same around 12% throttle opening and the airflow through main passage takes over beyond 25% opening. The novelty of this study is that airflow through the bypass is also predicted for different screw positions. From the analysis of results, it is found that with around two turns of bypass screw opening, the required amount of air flow rate could be achieved through the bypass passage to run the accessories of the engine at idling and also to meet the required performance and emissions levels as per the design target. In addition, there is a good agreement of CFD predictions with experimental results with an error of about 6%. Finally, it is concluded that the procedure adopted in this study to design the throttle body as per engine specifications will be very useful for the engine designers and in this aspect, CFD plays an important role. Source

Suresh Kumar J.,UCAL Fuel Systems Ltd | Ganesan V.,Indian Institute of Technology Madras | Mallikarjuna J.M.,Indian Institute of Technology Madras | Govindarajan S.,UCAL Fuel Systems Ltd
SAE Technical Papers | Year: 2013

In order to achieve good fuel spray characteristics, proper placing of the fuel injector in the intake manifold in port fuel injected (PFI) gasoline engines is very crucial. In automotive PFI engines, vehicle layout may be a constraint to mount the fuel injector in best possible location and inclination. In general, PFI engines use straight spray fuel injection. However, if there is a vehicle layout constraint, then inclined fuel spray may be suitable which is not very common. Hence, it is important to understand the effect of fuel spray inclination on fuel spray characteristics. In this study, a CFD analysis has been carried out for the four inclinations of fuel spray and the results are compared. The geometrical modeling of the fuel injector is done using ProE software. It is meshed with polyhedral cells and mesh refinement is done wherever required. Inlet air velocity and exit pressure of intake pipe at wide-open-throttle conditions are used as boundary conditions. In this study, droplet size distribution, sauter mean diameter (SMD), fuel penetration and evaporation rate are analyzed. Also available actual mass flow rate of the fuel injector with straight fuel spray are compared with numerical predictions. From the analysis of the results, it is found that straight fuel spray is preferable in terms of good fuel spray characteristics. However, if vehicle layout does not permit it, then 5° inclined spray may be used, without compromising much on fuel spray characteristics. © 2013 SAE International. Source

Suresh Kumar J.,UCAL Fuel Systems Ltd | Ganesan V.,Indian Institute of Technology Madras | Mallikarjuna J.M.,Indian Institute of Technology Madras | Govindarajan S.,UCAL Fuel Systems Ltd
SAE Technical Papers | Year: 2013

In modern direct injection gasoline engines, air-fuel mixing has a strong influence on combustion and emission characteristics, which in turn largely depends on in-cylinder fluid motion. However, in-cylinder fluid motion dependent on many engine parameters viz., piston shape, engine speed, intake manifold orientation, compression ratio, fuel injection timing, duration, etc. Among them, piston shape has significant influence on the in-cylinder fluid motion. Therefore, this study aims on evaluating the effect of piston shape on in-cylinder flows in a direct injection engine using CFD. In this study, a single-cylinder, two-valve, four-stroke direct injection engine designed for two-wheeler application in India is considered for the analysis. 'STAR-CD' and és-ice' are used for CFD analysis. Pressure boundary values obtained from measurements in the actual engine are employed. Two piston-shapes viz., flat and bowl types at wide-open-throttle under non-firing conditions are considered. Mainly analysis has been done to obtain in-cylinder velocity vector fields and in-cylinder flows, which are characterized by tumble ratio and turbulent kinetic energy. In addition, motoring experiments were conducted on an actual engine to measure in-cylinder pressure variation in order to compare it with CFD results. From the analysis of results, it is found that bowl shaped piston generates higher TR and TKE than those of flat piston by about 15 and 12% respectively. © 2013 SAE International. Source

Sivanantham R.,UCAL Fuel Systems Ltd | Sureshkumar J.,UCAL Fuel Systems Ltd
SAE Technical Papers | Year: 2010

Emerging trend in the automotive industry all around the world is to develop vehicles to consume less fuel and to meet stringent emission norms by using engines of higher power to weight ratio and higher thermal efficiency. These advanced technology engines designed for high power output will use low viscous oil to reduce frictional losses and will operate at elevated temperature levels. Hence, the various auxiliaries and parts of these engines should be adaptable for the use of low viscous oil and should withstand higher temperatures. Oil pump is one such auxiliary which will be subjected to work with low viscous oil at higher temperatures levels. The oil pump taken for study and design improvement is an internal gear type positive displacement oil pump, used in a passenger car diesel engine. The un-meshing of the gears causes the inflow and meshing causes the outflow of lubricating oil. This process occurs continuously for providing a smooth pumping action. The oil pump designed for higher viscous oil will exhibit low performance when low viscous oil is used. The performance of these pumps will further go down at the elevated thermal levels of engine. The parameters selected to study this effect on oil pump performance are i) Clearances between the moving elements and the housing, ii) Passages for flow of oil inside the pump and from the pump to the engine. Each element was modified and the pump with the modifications- separately and in combinations-was tested for flow and pressure characteristics. From the experimental results, it was observed that the Oil flow rate improved around 15% for the given pressure specifications with the modification of the design parameters. In addition to the flow improvement the power consumption by the oil pump decreased by more than 15%. Copyright © 2010 SAE International. Source

Ganesan V.,Indian Institute of Technology Madras | Suresh Kumar J.,UCAL Fuel Systems Ltd
SAE Technical Papers | Year: 2013

This paper presents the details of the study to optimize and arrive at a design base for a vacuum pump in an automotive engine using resilient back propagation algorithm for Artificial Neural Networking (ANN). The reason for using neural networks is to capture the accuracy of experimental data while saving computational time, so that system simulations can be performed within a reasonable time frame. Vacuum Pump is an engine driven part. Design and optimization of a vacuum pump in an automotive engine is crucial for development. The NN predicted values had a good correlation with the actual values of tested proto sample. The design optimization by means of this study has served the purpose of generating the data base for future development of different capacity vacuum pumps. The ANN approach has been applied to automotive vacuum brake for predicting the optimized evacuation time and the power for a vacuum pump of 110 cc capacity with vacuum tank capacity of 3 cc at pressure of 500 mbar. The ANN predictions for the evacuation time and power of the tested vacuum brake yielded a good statistical performance with mean square error of 8.21152 e-3 and regression value between 0.9904 e-01. Comparisons of the ANN predictions and the experimental results demonstrate that to automotive vacuum brake can accurately be modeled using ANNs. Consequently, with the use of ANNs, the evacuation time and power of the brake can easily be determined by performing only a limited number of tests instead of a detailed experimental study, thus saving both time and cost. As a result the proposed NN model has strong potential as a feasible tool for the prediction of evacuation time of a vacuum pump used in automobile brakes. © 2013 SAE International. Source

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