Manivannan P. V.

A two-degree freedom air fuel ratio controller (Model based feed forward transient plus closed loop Proportional Integral-Derivative (PID) steady state controllers) developed for controlling the air fuel ratio of the charge in a small displacement (125 CC) SI engine is presented. The feed forward controller's airflow and injector models were developed after conducting extensive experiments on the engine modified for the Port Fuel Injection (PFI) operation. A dynamic air fuel ratio model obtained (air fuel ratio changes measured using an UEGO sensor) by injecting the Pseudo Random Binary Signal (PRBS) signal in addition to base line fuel injection pulse, was used for designing the PID controller. Optimal PID gain values were identified using Nelfer-Mead optimization technique. The control algorithms were implemented and optimized using SIMULINK blocks that are run under dSPACE on the MicroAuto box hardware. The optimized control algorithms were ported on the specially designed, in-house built, low cost engine management system (EMS) developed around an 8-bit microcontroller. The spark timing was also controlled simultaneously for knock free operation. The two-degree freedom air fuel ratio controller could maintain the air fuel ratio under steady and transient conditions closely. High thermal efficiency and low HC & NOx emissions were achieved using the developed EMS. At higher speed elevated NOx emission was observed, due to the use of leaner mixture. The improvements are expected to be higher if a suitable smaller injector is used. Copyright © 2012 by ASME.

An idle speed engine model has been proposed and applied for the development of an idle speed controller for a 125 cc two wheeler spark ignition engine. The procedure uses the measured Indicated Mean Effective Pressure (IMEP) at different speeds at a constant fuel rate and throttle position obtained by varying the spark timing. At idling conditions, IMEP corresponds to the friction mean effective pressure. A retardation test was conducted to determine the moment of inertia of the engine. Using these data, a model for simulating the idle speed fluctuations, when there are unknown torque disturbances, was developed. This model was successfully applied to the development of a closed loop idle speed controller based on spark timing. The controller was then implemented on a dSPACE Micro Autobox on the actual engine. The Proportional Derivative Integral (PID) controller parameters obtained from the model were found to match fairly well with the experimental values, indicating the usefulness of the developed idle speed model. Finally, the optimized idle speed control algorithm was embedded in and successfully demonstrated with an in-house built, low cost engine management system (EMS) specifically designed for two-wheeler applications. © 2011 The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg.

The present article describes the generation of copper nanoparticles in the base fluid using developed micro-electrical discharge machining (micro-EDM) process. Micro-EDM was performed with various operating parameters such as voltage, current, pulse width and duty factor. To prevent agglomeration and coagulation of nanoparticles, polyvinyl alcohol (PVA) and polyethylene glycol (PEG) are used as stabilizers. The characterization of the generated copper nanofluid is done by energy dispersive analysis by X-rays, selected area electron diffraction pattern and transmission electron microscope followed by the study of thermal conductivity and viscosity of nanofluid using KD-2 pro device and falling ball type viscometer. The viscosity measurement enables to determine the dispersion stability of copper nanofluids. The experimental results show that the mean size of generated spherical copper nanoparticles is found to be less than 10 nm. It was observed that the thermal conductivity of copper-de-ionized (DI) water, copper-DI water with PVA and PEG nanofluids are 6%, 14% and 15% are higher than that of pure DI water. Also, it was found that there is a reduction of 96% and 99.9% in the sedimentation velocity of copper nanoparticles in copper-DI water with PVA and PEG nanofluid when compared to copper-DI water nanofluid resulting in excellent dispersion stability of the nanoparticles in copper-DI water with PEG nanofluid rather than PVA nanofluid. © 2014 Taylor & Francis Group, LLC.

The present work deals with development of a Target tracking system based on Monocular Vision for an Autonomous Defence Vehicle without a global satellite view. The vehicle is also equipped with ultrasonic sensors to gauge distance from the target at any point of time. In this work, theoretical expressions have been arrived at for control of motors for accurate capture of target without image capture of the targeting pointer itself. This can greatly reduce the costs as the high resolution cameras required for capture of targeting pointer (generally a LASER pointer) are very costly. Theoretical expressions have also been determined for the approach distance in dependence only on camera, motor specifications and the target size. A prototype system was developed along with the necessary real time embedded controller and image processing algorithms for identifying the target and to control targeting system LASER pointer. Experiments were conducted to find out efficacy of developed system. The system is able to detect the target on different approach distances and camera cone angles. It should be noted that the target size will also be calculated on the fly by the robot itself. This makes it possible for deployment of this targeting module without much change to the existing system.