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This paper presents the results of tests using a prototype pump-integrated port fuel injector that is designed for small gasoline engines. The unique construction of the injector eliminates the need for a separate feed pump. The device is intended as a solution to meet the upcoming emission norms similar to Euro 6 standards, to be implemented in Asian countries. In particular, the Indian two-wheeler market which produces around 20 million vehicles annually [1], migrates to Bharat Stage VI (BS VI) emission standards in the year 2020. This market is largely cost-driven and currently most of the motorcycles use carburettors as fuelling systems. It is expected that the adoption of port fuel injection would be inevitable to meet the BS VI emission norms. To minimize the increase in cost due to such a change, a new injector is developed, which integrates the fuel pump within the injector, making the system simple and compact, while calling for no change in the fuel tank.

This paper presents work performed to improve an engine's fuel economy by introducing ultrasonic atomization as the method of fuelling. An ultrasonic atomizer was added to the air intake path of a four stroke spark-ignited two-wheeler engine, replacing the conventional carburetor. Test results indicate that the engine BSFC reduced by around 20% due to lower pumping losses and lean operation facilitated by better fuel atomization. Less throttling also reduced the pressure difference between the air filter and combustion chamber, especially at lower speeds and low loads. This reduced exhaust gas dilution into the intake manifold and hence a rich mixture was not required for stable operation even at idling conditions. HC emissions are seen to be high and will need to be addressed, but NO emissions reduced significantly.