Experimental Investigation of Spark-Ignited Combustion with High-Octane Biofuels and EGR. 1. Engine Load Range and Downsize Downspeed Opportunity

The present study experimentally investigates spark-ignited combustion with 87 AKI E0 gasoline in its neat form and in midlevel alcohol–gasoline blends with 24% vol/vol isobutanol–gasoline (IB24) and 30% vol/vol ethanol–gasoline (E30). A single-cylinder research engine was used with an 11.85:1 compression ratio, hydraulically actuated valves, laboratory intake air, and was capable of external exhaust gas recirculation (EGR). Experiments were conducted with all fuels to full-load conditions with λ = 1, using both 0% and 15% external cooled EGR. Higher octane number biofuel blends exhibited increased stoichiometric torque capability at this compression ratio, where the unique properties of ethanol enabled a doubling of the stoichiometric torque capability with E30 as compared to 87 AKI, up to 20 bar IMEPg (indicated mean effective pressure gross) at λ = 1. EGR provided thermodynamic advantages and was a key enabler for increasing engine efficiency for all fuel types. However, with E30, EGR was less useful f...

[1]  B. Zwolinski,et al.  Physical and Thermodynamic Properties of Aliphatic Alcohols , 1973 .

[2]  Wayne Moore,et al.  Investigation of Knock Limited Compression Ratio of Ethanol Gasoline Blends , 2010 .

[3]  B. West,et al.  The Impact of Low Octane Hydrocarbon Blending Streams on the Knock Limit of “E85” , 2013 .

[4]  Michael Howard Shelby,et al.  Octane Numbers of Ethanol-Gasoline Blends: Measurements and Novel Estimation Method from Molar Composition , 2012 .

[5]  Subramanian Ramanathan,et al.  Increasing EGR Tolerance using High Tumble in a Modern GTDI Engine for Improved Low-Speed Performance , 2013 .

[6]  James P. Szybist,et al.  Intermediate Alcohol-Gasoline Blends, Fuels for Enabling Increased Engine Efficiency and Powertrain Possibilities , 2014 .

[7]  John B. Heywood,et al.  Internal combustion engine fundamentals , 1988 .

[8]  John F. Thomas,et al.  Predicting Light-Duty Vehicle Fuel Economy as a Function of Highway Speed , 2013 .

[9]  Aaron Hula,et al.  Light-Duty Automotive Technology, Carbon Dioxide Emissions, and Fuel Economy Trends: 1975 Through 2015 , 2015 .

[10]  James P. Szybist,et al.  Experimental Investigation of Spark-Ignited Combustion with High-Octane Biofuels and EGR. 2. Fuel and EGR Effects on Knock-Limited Load and Speed , 2014 .

[11]  Darius Mehta,et al.  The Effect of EGR on Low-Speed Pre-Ignition in Boosted SI Engines , 2011 .

[12]  Michael Howard Shelby,et al.  Fuel Economy and CO 2 Emissions of Ethanol-Gasoline Blends in a Turbocharged DI Engine , 2013 .

[13]  Arvon L. Mitcham,et al.  Determination of the R Factor for Fuel Economy Calculations Using Ethanol-Blended Fuels over Two Test Cycles , 2014 .

[14]  Rolf D. Reitz,et al.  Efficiency and Emissions Mapping of RCCI in a Light-Duty Diesel Engine , 2013 .

[15]  Robert Albert Stein,et al.  Optimal Use of E85 in a Turbocharged Direct Injection Engine , 2009 .

[16]  Charles E. Newman,et al.  Effect of Ethanol on Part Load Thermal Efficiency and CO 2 Emissions of SI Engines , 2013 .

[17]  Michael Howard Shelby,et al.  Effect of Heat of Vaporization, Chemical Octane, and Sensitivity on Knock Limit for Ethanol - Gasoline Blends , 2012 .

[18]  Charles E. Roberts,et al.  A Continuous Discharge Ignition System for EGR Limit Extension in SI Engines , 2011 .

[19]  N. Fraser,et al.  Challenges for Increased Efficiency through Gasoline Engine Downsizing , 2009 .

[20]  C. Stuart Daw,et al.  Analysis of the Impact of Selected Fuel Thermochemical Properties on Internal Combustion Engine Efficiency , 2012 .

[21]  Robert L. McCormick,et al.  Utilization of Renewable Oxygenates as Gasoline Blending Components , 2011 .

[22]  Timothy J. Wallington,et al.  Octane Numbers of Ethanol− and Methanol−Gasoline Blends Estimated from Molar Concentrations , 2010 .

[23]  Jerald A. Caton,et al.  A Comparison of Lean Operation and Exhaust Gas Recirculation: Thermodynamic Reasons for the Increases of Efficiency , 2013 .

[24]  Eric Nafziger,et al.  Load Expansion of Stoichiometric HCCI Using Spark Assist and Hydraulic Valve Actuation , 2010 .

[25]  Wayne Moore,et al.  HCCI Load Expansion Opportunities Using a Fully Variable HVA Research Engine to Guide Development of a Production Intent Cam-Based VVA Engine: The Low Load Limit , 2012 .

[26]  Charles E. Roberts,et al.  The Interaction of Fuel Anti-Knock Index and Cooled EGR on Engine Performance and Efficiency , 2012 .

[27]  Robert Albert Stein,et al.  An Overview of the Effects of Ethanol-Gasoline Blends on SI Engine Performance, Fuel Efficiency, and Emissions , 2013 .

[28]  Michael J. Brear,et al.  The octane numbers of ethanol blended with gasoline and its surrogates , 2014 .