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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.

Lubrication networks in today's passenger car engines are complex systems managing the interactions between the manufacturers' demand for long engine-life, low friction characteristics and sufficient heat-transfer work of the lubricant. Modern engines work harder and run hotter and consequently place more demands on the engine oil and the design of the lubrication system. The paper presents an overview of the influences of various oil pump parameters as oil pump suction port, rotor geometry and oil pump component clearances on the engine's operating behavior. The results of detailed investigations, intended to design the oil pump capacity exactly to the requirements of the optimized lubrication system, are shown in combination with the analysis of the oil draining system, aimed to reduce the hydraulic losses. A potential is presented that engine manufacturer can obtain in terms of saving energy.

Potential improvements in spark ignited engine performance gained through the application of ceramic valve train components were predicted using state-of-the-art valve train simulation and gas exchange computer programs. The use of ceramic valves, ceramic pushrods, and ceramic hydraulic tappet housings, in combination with modified valve spring and valve lift parameters, were analyzed for a 2.8L overhead valve V-6 engine. The results show that significant improvements in dynamic valve train behavior and engine performance are possible with the largest gains coming from the use of ceramic valves. Potential improvements in valve train dynamics include: a 20% increase in maximum engine speed; a 30% reduction in the maximum valve train forces; and a 30% reduction in valve train friction. These benefits can then be used to either improve fuel economy, high speed engine power or low speed torque by up to 5%.

To drive the camshafts in modern 4-stroke-engines, roller chains or toothed belts are normally used. These components are highly loaded during engine operation, especially due to torque fluctuations at the camshafts and torsional vibrations of the crankshaft. The stresses can be increased due to vibration excitation in the drive. The goal of this paper is to describe a simulation model for the dynamic behavior of camshaft drive systems. First, the boundary conditions in a camshaft drive of an IC-engine are analysed and evaluated. Then, possible methods of mathematical simulation are discussed. Finally, to show the accuracy of the model, some calculation results are shown in comparison to corresponding measurements.

Hydraulic lash adjusters are standard construction units in modern valve trains. Nevertheless, due to the sensitivity of the lash adjusters a special knowledge of the correlation between the response and the vibration excitation of the entire valve train is required. An analysis of the lifter shortening behavior as well as the lifter stiffness was carried out utilizing measurements of the relative movement of the plunger to the housing of the lifter, the check-valve displacement, the force profiles in the system, and the valve lift. It was found that the lifter dynamics and resonance effects in the valve train have a considerable influence on the valve bounce velocity. The influence of the cam kinematics on the response of the entire system is demonstrated using the example of the valve bounce velocity.

The loads which act upon the crankshaft are analyzed and its reactions are described. A typically and practically known calculation procedure for crankshafts is compared with various calculation procedures of classification societies and a draft from the CIMAC* working group “Crankshafts”. The CIMAC draft serves as basis for a standardization of design requirements of all classification societies which is currently under negotiation between the CIMAC and the IACS**. The differences among the calculation procedures are presented and evaluated. The need for a uniform calculation procedure accepted world-wide by all classification societies is shown. The possibilities opened by the availability of modern techniques in developing more detailed and thus more accurate calculation models are pointed out.

A mathematical equivalent model to describe the dynamic behaviour of mechanical actuated valve trains has been developed which is based on a multi-degrees-of-freedom vibratory system. It could be shown that dampings and stiffnesses efficient in a valve train are influenced by three oil film effects: these are squeeze films between the valve train components, elastohydrodynamic lubrication of cam and follower and the cam shaft bearings. Thus, the effective values for dampings and stiffnesses within the equivalent model are calculated with regard to these different kinds of oil film effects. The accuracy of the model is demonstrated by a comparison to measured forces and accelerations which were taken up on a pushrod-actuated valve train.