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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.

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.

Variable valve timing represents one of the key technologies in further development of automotive engines. Different valve lift profiles and variable valve timing in the engine operation map offer the flexibility to better meet the load specific engine requirements regarding the intake flow conditions, the exhaust gas control and the efficiency of load exchange, mixture preparation and combustion.

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.

Variable valve timing is one of the key technologies in the further development of automotive engines. A variation of valve lift profiles and variable valve timing in the engine operation map offer the flexibility to better meet the load specific engine requirements regarding the intake flow conditions, the exhaust gas control and the efficiency of load exchange, mixture preparation and combustion. This paper describes solutions of variable valve lift systems for both a two or three-step switchable system as well as the actual design of the continuously variable valve lift system VVH. The system properties will be described and analyzed regarding their specific benefits in fuel economy, emission behavior and performance as well as regarding the systems trade-off. Optimization strategies regarding a two or three-step variable maximum valve lift are pointed out and will be compared to the continuously variable intake valve timing.

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%.

A variable valve actuation mechanism suitable to activate and deactivate the intake and exhaust valves of reciprocating engines will be presented within this paper. This system called the “CVD System” (Cylinder and Valve Deactivation) allows a reliable activation and deactivation of the valves of conventional cam-controlled valve trains within one engine cycle, independent of the oil feeding system. The system can be used for both the deactivation of single valves of multi-valve engines - e.g. to increase the in-cylinder charge motion - or the deactivation of complete cylinders of multi-cylinder engines. Different to the well known hydraulic valve shifting or switching devices the CVD system represents an electromechanical device with an unlocked (deactivated) position being mechanically offered to a solenoid operated coupling lever once per cam revolution. If valve deactivation is required the solenoid is switched on to cut the force line between cam and valve.

The VVH System - Variabler (variable) Ventil (valve) Hub (lift) - is a variable valve timing system suitable for an unthrottled load control of spark ignition engines. This mechanical valve train system allows a continuously variable intake valve lift from zero to maximum with a corresponding variable intake closing. Based on a first introduction of the VVH system during the SAE '98 Annual Congress this paper gives a more detailed description of this technology and reports about the progress of development. In a first part of this paper a systematic design study showing application variants of the principle design proves that the VVH technology can be designed for all kinds of combustion engines with poppet valves including two and multi-valve cylinder heads, engines with over-head cam drive or pushrod valve train, inline or V-engines.