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Technische Univ. Braunschweig
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Optical Investigation of Mixture Formation in a Small Bore DISI Engine by Laser Induced Exciplex Fluorescence (LIEF)

Technische Univ. Braunschweig-Alexander Pauls, Peter Eilts
Published 2019-09-09 by SAE International in United States
Legislative and customer demands in terms of fuel consumption and emissions are an enormous challenge for the development of modern combustion engines. Downsizing in combination with turbocharging and direct injection is one way to increase efficiency and therefore meet the requirements. This results in a reduction of the displacement and thus the bore diameter. The emerging trends towards long-stroke engine design and hybridization make the use of small bore diameters in future gasoline engines a realistic scenario. The application of direct injection with small cylinder dimensions increases the probability of the interaction of liquid fuel with the cylinder walls, which may result in disadvantages concerning especially particulate emissions. This leads to the question which bore diameter is feasible without drawbacks concerning emissions as a result of wall wetting. In the previous project “GDI Boundary Bore” the feasibility of an SI engine with direct injection and small bore diameter (60 mm) was shown by the analysis of two different cylinder head concepts (3V and 4V). For the acquirement of deeper understanding of the mixture formation in…
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Timing Implications of Sharing Resources in Multicore Real-Time Automotive Systems

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Technische Univ. Braunschweig-Mircea Negrean, Simon Schliecker, Rolf Ernst
  • Journal Article
  • 2010-01-0454
Published 2010-04-12 by SAE International in United States
The topic of timing has already been recognized as a major challenge when designing safety-critical automotive architectures. Consequently the availability of appropriate performance and timing analysis methods is key to building reliable automotive electric and electronics (E/E) and software architectures. Due to the potential performance increase, power reduction and cost-efficiency multicore solutions for automotive real-time environments receive growing attention. But the prediction of the timing behavior for multicore electronic control unit (ECU) systems becomes more complicated. Even in setups with static task-to-processor mapping, the execution of the tasks is usually not independent. The use of the same physical hardware, such as memories, coprocessors, or network components, makes inter-core interference unavoidable and may introduce hard-to-find timing problems including missed deadlines that can finally make the entire system fail. With this work we anticipate new issues on the timing prediction in the upcoming automotive multicore ECUs, we discuss difficulties and solutions in the evolution from distributed single-core systems to multicore systems and also provide a modeling and analysis approach of complex real-time multicore systems with shared resources.
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Formal Timing Analysis of Full Duplex Switched Based Ethernet Network Architectures

Technische Univ. Braunschweig-Jonas Rox, Rolf Ernst
Published 2010-04-12 by SAE International in United States
Ethernet could be a promising solution to satisfy the increasing bandwidth requirements of future automotive systems. While the non-deterministic timing behavior of standard Ethernet makes its application unsuitable for time critical systems, different real-time Ethernet solutions which ensure bounded communication delays exist and are also already employed in the industry. A common aspect of the existing solutions is the full duplex switched Ethernet network architecture on which they are based. This makes it possible to guarantee the existence of an upper bound of the message latency, but the determination of this bound is far from trivial in most cases. For the determination of the message latency, the behavior of all sources of traffic on the network has to be taken into account. Specifically, one must consider the maximum frame size transmitted by any device, the scheduling parameters of the frames (e.g. Class of Service (CoS) priorities), and the time distribution and rate of frames. In this paper, we present how the concepts used in compositional system level performance analysis can be adapted to analyze full…
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