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Univ of California-Berkeley
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Methods and Tools for Calculating the Flexibility of Automotive HW/SW Architectures

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Univ of California-Berkeley-Liangpeng Guo, Alberto Sangiovanni-Vincentelli
General Motors-Paolo Giusto
  • Journal Article
  • 2012-01-0005
Published 2012-04-16 by SAE International in United States
To cope with the increasing number of advanced features (e.g., smart-phone integration and side-blind zone alert.) being deployed in vehicles, automotive manufacturers are designing flexible hardware architectures which can accommodate increasing feature content with as fewer as possible hardware changes so as to keep future costs down. In this paper, we propose a formal and quantitative definition of flexibility, a related methodology and a tool flow aimed at maximizing the flexibility of an automotive hardware architecture with respect to the features that are of greater importance to the designer. We define flexibility as the ability of an architecture to accommodate future changes in features with no changes in hardware (no addition/replacement of processors, buses, or memories). We utilize an optimization framework based on mixed integer linear programming (MILP) which computes the flexibility of the architecture while guaranteeing performance and safety requirements.
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Maximizing Power Output in an Automotive Scale Multi-Cylinder Homogeneous Charge Compression Ignition (HCCI) Engine

Univ of California-Berkeley-Samveg Saxena, Jyh-Yuan Chen, Robert Dibble
Published 2011-04-12 by SAE International in United States
Experimental investigations were conducted on a multi-cylinder automotive scale HCCI engine in determining a strategy that yields high power output, sufficient for passenger vehicles. A 1.9L Volkswagen TDI, modified for HCCI operation, is used with a compression ratio of 17:1 and boost pressures between 1.0 and 2.0 bar absolute. Various equivalence ratios and combustion times are explored at 1800 RPM with commercial-grade gasoline. The effects of exhaust backpressure that would be caused by a turbocharger in production engines are also explored.The results reveal that the highest power output can be achieved with high boost pressures and high equivalence ratios, and highly delayed combustion timing for controlling ringing. The optimal power output conditions exist near the boundaries of ringing, peak in-cylinder pressure, misfire and controllability. The results of the highest power output condition are displayed for a single cylinder; however, similar trends were seen across all four cylinders of the HCCI engine. The maximum power output identified in this study exceeded 9 bar gross IMEP, and high indicated efficiency points (exceeding 40%) were also found. NOx…
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