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Kale, Vaibhav
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Development of an Improved Residuals Estimation Model for Dual Independent Cam Phasing Spark-Ignition Engines

Michigan Technological Univ-Vaibhav Kale, Yeliana Yeliana, Jeremy Worm, Jeffrey Naber
Published 2013-04-08 by SAE International in United States
Estimating internal residual during engine operation is essential to robust control during startup, steady state, and transient operation. Internal residual has a significant effect on combustion flame propagation, combustion stability and emissions. Accurate residual estimate also provides a better foundation for optimizing open loop fuel control during startup, while providing a basis for reducing emissions during closed loop control.In this paper we develop an improved model to estimate residual gas fraction by means of isolation and characterization of the physical processes in the gas exchange. Examining existing residuals model as the base, we address their deficiencies making changes to appropriate terms to the model. Existing models do not work well under wide angle dual independent cam phasing. The improved residual estimation model is not limited by the initial data set used for its calibration and does not need cylinder pressure data. The model can work with different valve lift profiles and compression ratios. The model is calibrated by using two datasets, a single cylinder engine simulation dataset comprising of a range of speeds from 180…
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Combustion Robustness Characterization of Gasoline and E85 for Startability in a Direct Injection Spark-Ignition Engine

GM Powertrain-Halim Santoso, Craig Marriott
Michigan Technological Univ-Vaibhav Kale, Jeremy Worm, Jeffrey Naber
Published 2012-04-16 by SAE International in United States
An experimental study and analysis was conducted to investigate cold start robustness of an ethanol flex-fuel spark ignition (SI) direct injection (DI) engine. Cold starting with ethanol fuel blends is a known challenge due to the fuel characteristics. The program was performed to investigate strategies to reduce the enrichment requirements for the first firing cycle during a cold start. In this study a single-cylinder SIDI research engine was used to investigate gasoline and E85 fuels which were tested with three piston configurations (CR11F, CR11B, CR15.5B - which includes changes in compression ratio and piston geometry), at three intake cam positions (95, 110, 125 °aTDC), and two fuel pressures (low: 0.4 MPa and high: 3.0 MPa) at 25°C±1°C engine and air temperature, for the first cycle of an engine start. The goal of this work was to simulate, test and investigate the engine's initial combustion cycle (1st fired cycle) including engine speed, manifold pressure, fuel pressure and ambient temperature (FTP testing temperature). The results revealed several trends with respect to hardware and fuel interactions: for gasoline,…
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