COMPARATIVE RESEARCH ON THE POTENTIAL FUEL ECONOMY OF DIESEL AND SPARK-IGNITION ENGINES

Comparative data are presented on the potential for fuel economy improvement via integrated powertrain electronic control in a spark ignition engine and by use of a prechamber and direct injection in a small diesel engine. The data presented are based on a reference passenger car of 1150 kgm. weight and acceleration times as follows: from 50 kph to 70 kph in 5.5 sec.; to 90 kph in 10.5 sec.; to 110 kph in 17 sec.; and to 130 kph in 26 sec. Manual five-speed transmission is assumed in all cases. For the spark ignition engine, data are presented on the tradeoff between fuel economy and emissions for a specific electronic control system (absolute minimum fuel-consumption calibration, minimum fuel consumption calibration with emissions constraints, the stoichiometric approach with and without exhaust gas recirculation, and the lean burn approach). The additional gains of transmission control are discussed and a research stepped transmission prototype is presented. A complete picture of fuel economy and emissions in various configurations of a prechamber diesel engine is presented. The gains in adopting direct injection are discussed and data on a research prototype engine of 1.5 L displacement are presented. Analysis of the data led to the following conclusions. The electronically controlled spark ignition engine and the prechamber diesel are essentially equivalent for missions having low power demand; for intermediate missions, the diesel is superior. Turbocharging of the diesel brings about important improvements for low and intermediate missions. At high speed, the three engines are equivalent. The direct-injection, turbocharged diesel is superior over the entire range of missions.

• Supplemental Notes:
  • Published in HS-805 233 (TRIS 361554), "International Automotive Fuel Economy Research Conference (1st) Proceedings," Washington, D.C., 1980, pp 139-58. Conference held October 31-November 2, 1979. Research sponsored by U.S. Department of Transportation and Italian Research Council.
• Corporate Authors:

  Fiat Research Center

  Strada Torino 10043, Orbassano 50
  Turin,   Italy 
• Authors:
  • Chinaglia, L
  • Conti, L
  • Cornetti, G
  • Montanari, V
  • Rinolfi, R
• Publication Date: 1980

Media Info

• Features: References;
• Pagination: 20 p.

Subject/Index Terms

• TRT Terms: Alternatives analysis; Diesel engines; Exhaust gases; Fuel consumption; Research; Spark ignition engines; Turbochargers
• Old TRIS Terms: Turbocharging
• Subject Areas: Energy; Research; Safety and Human Factors;

Filing Info

• Accession Number: 00370530
• Record Type: Publication
• Source Agency: National Highway Traffic Safety Administration
• Report/Paper Numbers: HS-031 352
• Files: HSL, USDOT
• Created Date: Feb 28 1983 12:00AM