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With the increased demand of mobility in the form of two-wheelers and the continued dominant share of Internal Combustion Engines (ICE) in Indian market, there is considerable influence on the deterioration of air quality. The regulators in this region have legislated Bharat Stage 6 (BS6) as a measure to restrict tail pipe emissions, which necessitates the automotive industry to work towards emission optimization measures. Some of the factors influencing this includes, air-fuel mixture formation, spray targeting, fuel properties, flow dynamics, combustion chemical kinetics, exhaust after-treatment etc. The focus area of this paper is to study the influence of air-fuel mixture formation which is highly dependent on fuel droplet atomization, injection timing, fuel injector, injection pressure and mixture preparation techniques to reduce the engine out emissions.

Personal mobility is evolving in the emerging markets, where the primary need for transportation is met with two wheelers. This reflects on the annual production volumes, which is forecasted to reach 160 million units by 2021[1]. Around 28% of this volume belong to electric two wheelers from China and the remaining are predominantly Internal Combustion Engines (ICE). With the regulators across the globe planning to enforce stricter emission norms in order to improve the air quality and owing to similar demand from the end customers, there is a need for technology to evolve towards harnessing the best energy efficiency using multiple technologies/architectures. However, considering that the majority of two wheelers are used by a population which is cost sensitive, it is imperative that efficient topologies need to be made available at affordable costs. The authors attempt to decipher this need for personal mobility coupled with the stringent regulations.

Increased penetration of gasoline EFI (Electronic Fuel Injection) in the Indian two wheeler commuter segment, demands simplified, but robust solutions. Freedom for the end user to adjust the idle speed with carbureted engines is considered as reference behavior. Control of idle air flow in the traditional throttle body designs is through a bypass path with either an idle speed actuator or a mechanical screw. Due to the quality of air and vented blow-by in the air path, field issues observed on most throttle body designs include a) carbon deposition influencing the air flow characteristics b) consequent effects included instability of idle speed, jamming of throttle valve or clogging of idle air control valve. One of the design measures suggested [1] was to introduce an idle screw on the throttle flap to retain the user experience based on the incumbent carburettor and address the carbon deposition based on the knowledge of ETB (Electronic Throttle Body).