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Common rail diesel injectors are multi-domain systems with complex interactions between mechanical, hydraulic and electrical components. For a detailed understanding of the dynamic behavior and for further performance improvements, often simulation models are indispensable. Injection dynamics is influenced by the opening and closing dynamics of the solenoid valve. Therefore an accurate simulation model of the solenoid valve is necessary for injector simulations. The objective of this study is to present a validated simulation model of the solenoid valve of a commercially available common rail diesel injector. For modeling the solenoid valve, a division into a mechanical and a magnetic submodel is done. The mechanical submodel is made up by a two mass system representing the pin and the armature of the solenoid valve. Contacts are modeled using linear-elastic spring-damper elements and viscous damping is considered for friction representation.

Apart from performance, comfort, cost and fun to drive, the reduction of fuel consumption has become a primary driver in the world market of the automotive industry. As continuously variable transmissions based on the pushbelt principle can be operated in an optimal state at any time, they are very suitable to meet the mentioned requirements. However, the power transmission in the system is very complicated. Both detailed measurements and simulations are necessary to understand and to optimize the physical mechanisms, power density and shift characteristics. The current paper presents a spatial simulation model for transient analysis at different levels of detail. An initial model based on non-smooth multi-body theory is outlined. It consists of two rigid pulleys each with one tilting loose sheave. The pushbelt comprises two ring packages based on the co-rotational approach.

Chain drives are used in powertrains for the kinematic coupling of the cam shaft, the ancillary units and the balancing shafts with the crank shaft. Advantages of chain drives are their high load carrying capacity along with increased durability whilst simultaneously being maintenance-free. A crucial issue in the drive is the optimization in regard of friction, further improving efficiency, reducing exhaust emission and abrasive wear. Modeling friction in drive systems requires precise description of the whole system dynamics. High-frequency oscillations occurring in the chain strands cause numerical problems in the friction computation. As a remedy, regularized friction curves are often used, being however not able to correctly determine all friction configurations and requiring a tradeoff between accuracy and computational efficiency.

The valve train plays a huge role in the performance of internal combustion engines by controlling the combustion process and is therefore one starting point to increase the efficiency of combustion engines. Considering the dynamics, the valve spring is the component with the lowest natural frequency in the motor and therefore plays a crucial role in the overall dynamics of the valve train. The spring force must be high enough to close the valve reliably and prevent the valves from bouncing of the seating due to surge modes after they have closed. Conversely, the spring force affect the friction level in the engine and therefore fuel consumption. For this reason the spring forces should be kept as low as possible. Modelling valve springs it has to be taken into account, that the dynamic response of the spring is substantially different from the static response.

Fully variable valve trains provide comprehensive means of adjustment in terms of variable valve timing and valve lift. The efficiency of the engine is improved in the operating range and in return, an increasing complexness of the mechanical design and control engineering must be handled. For optimization and design of these kinds of complex systems, detailed simulation models covering different physical domains, i.e. mechanics, hydraulics, electrodynamics and control are needed. Topic of this work is the variable valve train named Audi valvelift system (AVS) e.g. used in the Audi 2.8l V6 FSI engine. The idea of AVS is to use different cam lobes at different operating points. Each intake valve can be actuated by a large and a small cam. For full load, the two inlet valves are opened by the large cam profile - ideal for high charge volumes and flow speeds in the combustion chamber. Under partial load, the small cam profiles are used.

Nowadays, multi-body systems theory including bilateral and unilateral constraints is comparatively well established by means of set-valued force laws. Although methods of non-smooth mechanics enable a highly efficient modeling, they are not conventionally used in industrial practice. Therefore in the present paper a valve train including hydraulic elements like a hydraulic lash adjuster is modeled using above mentioned methods. A main focus is laid upon the treatment of contact problems and two different models are investigated. Contacts in multi-body dynamics are classically described using spring and damper elements minimizing penetration. This approach results in stiff differential equations with unintentional high eigenfrequencies and long computing times as well as uncertainties in the parameters for contact stiffness and damping. Whereas in rigid contact models the contact is supposed to be completely stiff leading to non-smooth systems.

In this work, the dynamics of hydraulic cam phasing systems are analyzed. First there will be introduced an experimental test rig, which is used to analyze the dynamical behavior of the cam phasers. The examined cam phaser, which operates like a slewing motor, is supplied with conditioned oil that matches real engine operation points. Secondly, a modular simulation approach for the cam phasing system and the whole valve train is presented. Additionally parameter studies are shown.

In this work several hydraulic chain tensioners with and without check valves are analysed. Using experiment and simulation the influence of the variation of the leakage gap on the performance of the tensioners is shown. Firstly, an experimental test setup to analyse the dynamical behavior of the tensioners is introduced. The tensioners can be excited kinematically with sinusoidal signals having amplitudes between 0.02mm and 1mm and frequencies up to 250 Hz. The temperature range of the measurements matches real engine operation points. Secondly, a modular simulation approach for the hydraulic tensioning systems is presented. These models are suitable for the integration in timing chain simulations. Hence, influences of parameter variations such as leakage gap variations are directly seen. Thirdly, a comparison between simulation and measured data is shown for the analysed hydraulic chain tensioners.