Environmental Engineering Reference
In-Depth Information
10
Biofuel Use from
Bioenergy Crops
Internal Combustion Engines
in Transportation
Jaclyn E. Johnson, Jeremy Worm,
Scott Miers, and Jeffrey Naber
Michigan Technological University
contents
10.1 Powertrain—Propulsion Systems ....................................................................................... 217
10.1.1 U.S. and World Transportation Fuel Usage .......................................................... 219
10.1.2 Biofuel Characteristics ......................................................................................... 220
10.1.3 Fuel Economy and CO
2
Regulations .................................................................... 224
10.1.4 Emissions Regulations .......................................................................................... 227
10.2 IC Engines .......................................................................................................................... 228
10.2.1 Basic Engine Operation ........................................................................................ 228
10.2.2 SI Engines ............................................................................................................. 229
10.2.2.1 Influence of Fuel on Operating Characteristics of SI Engines ............. 230
10.2.3 CI Engines (Diesel Engines)................................................................................. 231
10.2.3.1 Diesel Engine Emissions: NO
x
and PM ................................................ 232
10.2.4 Impact of Biofuels on Current Engine/Vehicle Operation ................................... 232
10.3 Summary ............................................................................................................................ 233
References ...................................................................................................................................... 234
10.1 PoWertraIn—ProPulsIon systems
Internal combustion (IC) engines are inherently linked to the specific physical, thermodynamic,
and chemical properties of the fuel and the effects of these properties on fuel-air preparation and
mixing, combustion initiation, combustion rates, combustion anomalies, and emissions formation.
Throughout history, different engine technologies have been developed and used to operate with
different fuels (Cummins 1989), including the 1908 Ford Model T, which operated on gasoline,
ethanol, and their blends.
In the United States, spark-ignited engines fueled with gasoline (gasoline engines) prevail
as the primary mover in light-duty vehicles (LDVs), representing 95% of the total LDVs in
the United States in 2008 (EIA 2009a). Spark-ignition (SI) engines are able to meet the most
stringent emissions standards, including U.S. Tier II Bin 2 and California partial zero emissions
vehicle (PZEV) standards, but they have a lower thermal efficiency with a peak at approximately
35% (U.S. DOE 2010a) in comparison to their counterpart, compression-ignition (CI) engines.
CI engines fueled by diesel fuel (diesel engines) are found in a high percentage of medium-duty
vehicles (MDVs) and dominate heavy-duty vehicle (HDV) and heavy equipment applications. See
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