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The performance of electrical vehicles strongly depends on characteristics of its energy storage system. A typical lithium-ion battery system is supervised by a battery management system to optimize operation and ensure safety over its whole lifecycle. Advanced battery management systems apply sophisticated fast charging procedures and active cell balancing. In future, impedance spectroscopy based on driving current stimulation for online estimation of the energy storage’s state of health can be expected. For efficient development and testing of such battery management systems it is impractical to use real lithium-ion cells in arbitrary condition of state of charge, temperature and state of health. Consequently, hardware in the loop cell emulators are state of the art. Most of them are limited to low frequency operation. In this paper, a novel modular wide bandwidth high performance lithium-ion cell emulator is introduced.

At present, diesel injection systems in automobiles with piezo element drives are replacing solenoid types due to their faster electro-mechanical properties. Their better fuel dosing characteristics offer lower fuel consumption, reduced noise and lower emissions. The limited elongation of the applied piezo elements within some tenth of micrometers makes these systems sensitive against mechanical tolerances, thermal effects and wear-out. Using the piezo element both as an actuator and as a sensor for the elongation and force allows an insight into the injector. The performance of this actuator-sensor behavior is shown together with a self-compensating loop for idle lift drift and a minimum fuel dosing control.

Plug-In Hybrid Electric Vehicles (PHEV) are becoming increasingly important as an intermediate step on the roadmap to Battery Electric Vehicles (BEV). Li-Ion is the most important battery technology for future hybrid and electrical vehicles. Cycle life of batteries for automotive applications is a major concern of design and development on vehicles with electrified powertrain. Cell manufacturers present various cell chemistries based on Li-Ion technology. For choosing cells with the best cycle life performance appropriate test methods and criteria must be obtained. Cells must be stressed with accelerated aging methods, which correlate with real life conditions. There is always a conflict between high accelerating factors for fast results on the one hand and best accordance with reality on the other hand. Investigations are done on three different Li-Ion cell types which are applicable in the use of PHEVs.

Advanced combustion strategies for direct injection gasoline engines require high performance fuel injectors. They must perform precise fuel metering, enhanced linear flow range and multi-pulse injection cycles in order to meet tight emission limits and low fuel consumption. Cold start is the most critical phase concerning emission levels. The performance of outwardly opening piezo-electric actuated fuel injectors is compared with conventional inwardly opening solenoid injectors. The investigation focuses on dosing performance, temperature influence and the impact of production tolerances. Besides full valve needle lift, both types of injectors are also analyzed in ballistic operating mode for minimum injection quantities. Compared to piezo injectors solenoid injectors show a much larger tolerance band at low fuel quantities. A new sensorless closed-loop control system results in substantial improvement of the dosing performance of solenoid injectors.

New cylinder impulse charge systems permit higher torque at low speed and promise substantial downsizing potential ongoing with reduced fuel consumption and lower emissions. Their immediate response avoids the disturbing delay of turbochargers. Using a fast switching valve in the air intake manifold, they generate a dynamic pressure increase, which provides higher cylinder air mass filling. The short transient times needed for the valve opening and closing process together with the required low air leakage rate call for an effective drive. Electromagnetic spring-mass actuators are well suited for this task. They generate high control forces over long distances and can be designed for transient times below 2 ms. However, they suffer from high impact energies at the stop positions und cannot be used without movement control for the armature. Tight commercial conditions restrict the application of sensors and complex hard- and software.

Battery aging is a main concern within hybrid and electrical cars. Determining the current state-of-health (SOH) of the battery on board of a vehicle is still a challenging task. Electrochemical Impedance Spectroscopy (EIS) is an established laboratory method for the characterization of electrochemical energy storages such as Lithium-Ion (Li-Ion) cells. EIS provides a lot of information about electrochemical processes and their change due to aging. Therefore it can be used to estimate the current SOH of a cell. Standard EIS methods require the excitation of the cell with a certain waveform for obtaining the impedance spectrum. This waveform can be a series of monofrequent sinusoidal signals or a time-domain current pulse with a dedicated Fourier spectrum. However, any form of dedicated perturbation is not generally applicable on board of an electric vehicle. This work presents a new passive spectroscopy method, which obtains the impedance spectrum directly out of real driving data.

The sensorless control of electromagnetic actuators for variable valve train derives the information about the valve movement directly from the current and voltage of the operating coils, no further sensor used at the actuator. The movement of armature and valve is heavily influenced by the cylinder pressure, especially during opening of the exhaust valve. Between two consecutive opening events, this pressure can vary by up to 3 bars. An early detection of pressure variation is essential in order to adjust the proper catching energy of the active coil. At the beginning of the armature movement, a degradation of the magnetic flux through the coils occurs which is caused by eddy-currents and magnetic remanence and results into an induced voltage. The information about the required energy adjustment of the catching coil can be calculated from this voltage. The algorithm allows a safe and soft landing at pressure variations of up to 3 bars.

Lithium-ion batteries are the most favored energy storage technology for high-efficiency hybrid and electrical vehicles. Online State-of-Charge (SOC) estimation is required for this application to estimate the remaining cruising distance. However, variation of battery parameters with temperature and cycle life has to be taken into account in order to achieve high accuracy. In this work electrical tests on lithium-ion cells in different States-of-Health are performed and used to extract model parameters such as open-circuit-voltage and impedance. High precision test equipment has been developed to accurately track the true SOC of the cell during measurements. A strong influence of cycle-life on electrical battery behavior is observed. A dynamic cell model based on the measurement results including temperature and aging effects is generated and subsequently used for SOC estimation with an Extended-Kalman-Filter.

Battery safety is the most critical requirement for the energy storage systems in hybrid and electric vehicles. The allowable battery temperature is limited with respect to the battery chemistry in order to avoid the risk of thermal runaway. Battery temperature monitoring is already implemented in electric vehicles, however only cell surface temperature can be measured at reasonable cost using conventional sensors. The internal cell temperature may exceed the surface temperature significantly at high current due to the finite internal electrical and thermal cell resistance. In this work, a novel approach for internal cell temperature measurement is proposed applying on board impedance spectroscopy. The method considers the temperature coefficient of the complex internal cell impedance. It can be observed by current and voltage measurements as usually performed by standard battery management systems.

The reliable access to electrically stored energy is becoming a critical parameter for the proper operation of modern vehicles. The total energy demand of electrical consumers in passenger cars is rising almost exponentially together with an increasing ratio of the peak to average current level. Such conditions can stimulate severe interactions between the various systems on the one hand, while on the other hand the battery charging state varies over a wide range. Recent field problems of high end cars from various vehicle manufacturers demonstrate the importance for an improved interaction analysis of the complete electrical system during the design phase and before the introduction of new functions. An efficient battery management is essential for modern vehicles to ensure a minimum state of charge and a proper lifetime of the battery. The electrical energy storage in hybrid vehicles which use the battery to buffer the combustion engine is even more important.

A new measurement system for dummy movement and chassis deformation in crash tests overcomes the restriction of blind areas in the existing photo camera observation. An inertial platform technique with micromechanical acceleration and rotation speed sensors is applied. Reconstruction of the original movement with tolerances of a few millimeters can be achieved. Various tests in automotive applications have demonstrated the performance and robustness of the system.

This work provides a new method for estimating the capacity of an automotive Lithium-Ion cell under real application conditions present in Hybrid and Electrical vehicles. Reliable online capacity estimation is needed for accurate prediction of the remaining electrical driving range. This is a crucial criterion for customer acceptance of Electrical vehicles. Dynamic excitations of real driving cycles, temperature variation as well as the variation of electrical battery behavior with capacity and resistance degradation are challenges that need to be overcome. For this paper, a long-term aging study on 120 automotive Lithium-Ion cells is evaluated with respect to the correlation between electrical cell behavior, temperature and the cell capacity over the complete cell lifetime. The results are used for a dynamic state-space model which provides the current-voltage relationship valid for all aging states of the battery.

Recent advances in energy density of Li-ion cells together with high-current fast charging ask for improved strategies for onboard safety and reliability observation of the cells. Potential degradation effects are stimulated by lithium plating and dendrite growth. The latter may ultimately cause an internal short circuit of the cell and can lead to serious damage. Increased self-discharge is an early indicator for safety-critical cell conditions. In this work, accelerated methods for self-discharge determination of Li-ion cells are presented. They are based on the analysis of cell voltage gradients during idle periods and can be applied in state-of-the-art battery management systems (BMS) performing low-drift measurement. However, transition into the idle state after driving requires a settling time of several hours before the voltage gradient can be extracted.

A promising approach for the variable valve actuation in spark ignition engines is based on electromagnetic actuators for the valve drive. The movement of the armature results from two opposite electromagnetic drives, supported by two springs. Without proper control of the current through the coils during flight time, the armature will hit the opposite position at high velocity, thus producing acoustical noise and reducing the lifetime of the actuator. This paper presents a new concept to achieve a soft landing with velocities in the range of 0.1 m/s. The applied control circuit requires no additional sensor for the valve position or speed and is only based on the observation of the electrical coil signals. Together with the optimized control strategy, the system complexity is minimized, which results into substantial cost savings.

Lithium ion technology is state of the art for actual hybrid and electrical vehicles. It is well known that lithium ion performance and safety characteristics strongly depend on temperature. Thus, reliable temperature measurement and control concepts for lithium ion cells are mandatory for applications in electrical cars. Temperature sensors for all individual cells increase the battery complexity and cost of a battery management system. Normally, temperature is measured on module level in current battery packs, without observation of the individual cell temperature. Sensorless cell impedance-based temperature measurement concepts have been published and are validated in laboratory studies. Dedicated test equipment is usually applied, which is not useful for automotive series application. This work describes a practical approach to enable impedance-based sensorless internal temperature measurement for all individual cells using state-of-the art battery management system components.

Precise fuel metering and high linear flow ranges (LFR) are the key issues for advanced injection systems for diesel and gasoline engines. They ensure lower emission, lower noise and higher fuel efficiency. Fast-switching solenoid injectors show high valve needle impact velocities and thus bouncing at injector closing. This causes multiple parasitic injections which reduce injection precision and deteriorates emission and efficiency. Mechanical and hydraulic anti-bounce concepts reduce the injection dynamic range while electronic open-loop controlled concepts are instable. For this reason a new sensorless electronic closed-loop anti-bounce solution able to reduce bouncing effectively and providing robust soft landing under all operating conditions was developed.

Fast charging capability is one of the key requirements for the success of electric vehicles. Considering the growing energy storage capacity of automotive batteries, fast charging can only be achieved using high-power charging systems. This leads to increased power dissipation inside the battery cells. The resulting heat generation inside the battery cell is a critical effect, as cell safety, performance and life time strongly depend on cell temperature and current. This must be considered by a simultaneous current and thermal battery management strategy, which requires reliable information about the individual cell temperature. Sensorless cell temperature can be derived from the cell impedance, where the charging current profile is superimposed by an excitation current and the resulting cell voltages are observed by the battery management system (BMS). An efficient algorithm for the impedance and temperature calculation can be implemented in actual BMS.

Replacing the traditional camshaft of spark ignition engines by a variable valve actuation (EVA) system promises noticeable fuel savings and substantial improvement of the motor torque [1]. Up to now, all known electromagnetic EVA systems apply one bulky central electronic control unit (ECU) together with complex wiring harness. A mechatronic approach for such system, where each actuator is joint together with its own control electronics, offers substantial performance and cost benefits. Extraordinary environmental conditions arise for such mechatronic system which is directly mounted on the cylinder head of the engine. Ambient temperatures up to 125°C together with vibrations, which are generated by the impact of the armature of the electromagnetic actuator, ask for a new assembly technique of the electronic. This paper describes the systematic approach for the design of such complex mechatronic system.

A test center for aging analysis and characterization of Lithium-Ion batteries for automotive applications is optimized by means of a dedicated cell tester. The new power tester offers high current magnitude with fast rise time in order to generate arbitrary charge and discharge waveforms, which are identical to real power net signals in vehicles. Upcoming hybrid and electrical cars show fast current transients due to the implemented power electronics like inverter or DC/DC converter. The various test procedures consider single and coupled effects from current profile, state of charge and temperature. They are simultaneously applied on several cells in order to derive statistical significance. Comprehensive safely functions on both the hardware and the software level ensure proper operation of the complex system.

Hybrid vehicles are becoming more and more attractive due to their reduced emissions and their higher fuel efficiency. Storage of electrical energy is the most critical aspect of hybrid automobiles. Therefore, an exact knowledge of the behavior of the battery and further electrical storage elements is mandatory. Their nonlinear characteristics over wide ranges of current magnitude, transient period, temperature and state of charge must be evaluated. Battery aging is another matter of increasing importance. For this reason, an automated battery test bench has been developed which is capable of reproducing high dynamic loads in both charging and discharging direction. Pulse rise times are in the range of a few microseconds at maximum currents up to 1500 A. The quasi-static charge and discharge power can reach 20 kW. Optimized characterization programs enable a rapid extraction of battery behavior parameters as well as capacitor characteristics.