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One of the major reason for lower efficiency and higher unburned hydrocarbon and carbon monoxide emission for two stroke engine is short circuit losses during the scavenging process. An attempt has been made in this study to understand and improve this phenomenon. A three dimensional transient CFD model is developed for a loop scavenged, Schnullar type, 70 cc two stroke engine. Three major processes, namely, blow down (expansion); scavenging and compression have been modelled. The model is validated with PIV measurement done in motoring mode. Model is also validated with experimental data for trapping efficiency with Watson method and for in-cylinder pressure during expansion, blow down and intake events. A good correlation is observed between experimental and simulation results. CFD model is used to quantify various parameters, such as, delivery ratio, trapping efficiency, scavenging efficiency, and amount of fresh mass short circuit at different load and speed points.

The Instant Mileage Assistance (IMA), as the name indicates, is a system to guide the vehicle users to realize maximum fuel economy (mileage). This system is targeted to provide users with instantaneous mileage indication depending on the current driving pattern, correct gear operating zone (in case of a geared vehicle) through gear up/down shift assist indication and the accurate distance the vehicle can travel before the fuel tank is empty, thereby assisting the user in harnessing maximum fuel economy the vehicle can deliver and also safely reach the next refilling station. The instantaneous mileage is calculated by mapping the distance travelled by the vehicle and the respective amount of fuel consumed, during a particular period of time, and is displayed using an instrument cluster.

The ionization current across the spark plug gap is obtained by applying a constant voltage using DC power source across the spark gap after the high-voltage discharge. The methodology involves study and comparison of different knock detection methods (cylinder gas pressure, accelerometer and ion current) through literature survey, development of analytical models (ionization current, chemical equilibrium, kinetic Nitric Oxides) to estimate crank angle resolved cylinder gas pressure from the measured values of ionization current. Model refinements and validations, development of Ignition Coil integrated DC power source and ion current measurement circuit, Transistorized Coil Ignition and microcontroller based knock controller have been carried out. Experiments have been conducted to validate the model with the reference method (cylinder gas pressure).