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The main targets concerning development activities for diesel engines are defined by future exhaust gas legislations (EURO IV, V). Due to the conflict between particulate and NOx emissions, both components of the exhaust gas are limited: The combination of direct injection of diesel into the combustion bowl and limited adoption of air swirl causes locally fuel-rich regions which lead to soot and burn at high peak temperatures in stoichometric regions. Simultaneously, the transient drive-off torque and the maximum power output are limited due to the time which is necessary for the mixture formation process. By means of intensified flow energy and a demand-oriented regulation of the air mass flow using an impulse charging device for diesel engines, locally fuel rich regions inside the combustion bowl can be minimized which finally influences the NOx-Soot Trade-Off by inside-engine measures and improves low-end torque and power characteristics.

This paper describes the principles, effects and the potentials of impulse charging systems applied to SI and Diesel engines. In general, impulse charging is realized by closing the inlet port upstream of the inlet valve during the intake stroke with an additional switching device. The piston, moving towards bottom dead center, generates a vacuum inside the combustion chamber and inlet port. By opening the switching device abruptly, the sub-atmospheric pressure level induces an enhanced volumetric efficiency due to the significantly increased gas dynamic effects in the intake manifold. One major advantage of impulse charging in comparison to the well known supercharging techniques lies in the dynamic behavior. The charging effect can be realized within one engine cycle. Furthermore, impulse charging provides high low-end torque, a nearly constant torque over a wide engine speed range with charging rates from 20% to 30%.

The Bharat Stage VI (BS-VI) emission legislation will come into force in 2020, posing a major engineering challenge in terms of system complexity, reliability, cost and development time. Solutions for the EURO VI on-road legislation in Europe, from which the BS-VI limits are derived, have been developed and have already been implemented. To a certain level these European solutions can be transferred to the Indian market. However, several market-specific challenges are yet to be defined and addressed. In addition, a very strict timeline has to be considered for application of advanced technologies and processes during the product development. In this paper, the emission roadmap will be introduced in the beginning, followed by a discussion of potential technology solutions on the engine itself as well as on the exhaust aftertreatment side. This includes boosting and fuel injection technologies as well as different exhaust gas recirculation methods.

The Bharat Stage (CEV/Tractor) IV & V emission legislations will come into force in Oct 2020 & Apr 2024 respectively, posing a major engineering challenge in terms of system complexity, reliability, costs and development time. Solutions for the EU Stage-V NRMM legislation in Europe, from which the BS-V limits are derived, have been developed and are ready for implementation. To a certain extent these European solutions can be transferred to the Indian market. However, certain market-specific challenges are yet to be defined and addressed. In addition, a challenging timeline has to be considered for application of advanced technologies and processes during the product development. In this presentation, the emission roadmap will be introduced in the beginning, followed by a discussion of potential technology solutions on the engine itself as well as on the after treatment components.