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To improve the performance and durability of two stroke engines, pressure, volume and temperature of crankcase are the important parameters which need optimisation. The paper investigates these scavenge parameters of a small two stroke engine with a view to alleviate its thermal conditions. Investigation of the pressure histories have been done with reference to pressure fluctuations, backflow, Kadenacy effect, list approximation, ring sticking, engine seizure, crankcase volume, crankcase temperature, cylinder barrel temperature, engine speed and physical parameters of the engine. By reducing the crankcase volume by 11 %, the maximum torque has increased by 11 % and shifted from 3000 RPM to 4000 RPM. The maximum power at 6000 RPM has increased by 12 %. Crankcase volume of 2 to 2.5 times the cylinder displacement is considered to be suitable.

Today's automotive Air Intake Systems are developed to deliver maximum filtration efficiency, maximum dust holding capacity and maximum service interval range based on engine performance and reliability requirements. It must also meet requirements of packaging, higher flow rates, lower pressure drop, lower noise, better fuel economy, increased vehicle speed/acceleration, high temperature compatibility, corrosion resistance, easy serviceability and cost effectiveness. It requires a well-behaved uniform flow with minimum temperature rise and pressure drop across the system. The air intake system should be installed such that no water ingress or water traces are found during the water wading test. These challenging requirements cannot be met effectively without a systems approach. The Air Intake System development process starts with selection of design methodology and evolution of checklists for System Design Specifications (SDS) and definition of targets.