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A single cylinder gasoline engine of a sports bike generates sufficient hot gases to pose great challenge to the designers of exhaust system. The high temperature exhaust gases in muffler creates thermal elongation on the solid parts of exhaust system, which is mounted on the chassis. This arrangement induces thermal stress in exhaust assembly. It is necessary to analyze this thermal stress to ensure the durability of muffler components. The exhaust design has a diversion at the header pipe to distribute the flow in two branches. This junction and the branches heated up excessively and showed repeated failure. To analyze the thermal stress, the temperature distribution in the muffler components is obtained from Computational Fluid Dynamics (CFD) analysis. The complete motorcycle with detailed exhaust system is modelled in the standard wind tunnel using a commercial CFD software.

In scooters, the Continuously Variable Transmission (CVT) is used to transmit the power from the engine to the wheels. The CVT transmission consists of a two pulleys connected to each other through a belt. The change in the transmission ratio is achieved due to the change in the pulley diameters. A centrifugal clutch is attached to the rear pulley to transmit the power to wheels once the engaging engine speed is reached. The heat is generated due to the belt slippage and the engagement of the centrifugal clutch. Excessive heating may damage the belt, clutch and deteriorate its performance. The cooling of the belt, pulleys and the clutch is thus important for its safe operation. The cooling is achieved by the centrifugal cooling fan which forces the air over the belt, pulley and clutch. A clear understanding of the cooling system is important in designing the air flow path for clutch cooling of CVT housing.

The Continuous Variable Transmission (CVT) in scooters is used to transmit the power from the engine to the wheels. The CVT transmission consists of a drive pulley and a driven pulley connected to each other through a belt. The centrifugal clutch is attached to the rear pulley which transmits the power to the wheel. The engagement and disengagement of the clutch generates heat and friction heat is generated between the belt and pulley, thereby requiring continuous external cooling for its safe operation. A centrifugal fan is employed for cooling of the CVT belt. Since the cooling fan takes air from atmosphere, there is always a possibility of dust from the atmosphere entering the system, which might cause wear of pulley and belt, thereby decreasing the performance of the transmission system. The objective of the work is to analyze the dust ingress pattern in to CVT housing.

Scooters are popular for the legroom available in the front and closed storage space beneath the seat. Engine is located at rear part of the vehicle beneath the storage space and is cooled by forcing the air by a centrifugal fan over the engine surface. Heat is rejected from the engine by the forced cooling and radiation to the surroundings. Storage space gets heated as result of excessive heat rejection from engine. To protect the material of storage space and the items stored in that, it is necessary to avoid heating of the storage space. The work aims to conduct the storage space heating analysis in a scooter. The objective is to propose the design modifications to reduce the storage space heating. The effect of convection and radiation in heating of the storage space is studied.