COMPARISON BETWEEN LEADED AND NONLEADED GASOLINE AS USED IN IOWA STATE HIGHWAY COMMISSION VEHICLES

THE OVERALL OBJECTIVE OF THIS EXPERIMENTAL PROGRAM WAS TO OBTAIN QUANTITATIVE COMPARISONS BETWEEN LEADED AND NONLEADED GASOLINES AS USED IN A VARIETY OF IOWA STATE HIGHWAY COMMISSION VEHICLES. THESE QUANTITATIVE COMPARISONS WERE TO BE MADE IN TERMS OF EXHAUST EMISSIONS, MAINTENANCE COSTS, AND FUEL ECONOMY. A 52-VEHICLE TEST FLEET WAS SELECTED WHICH INCLUDED TRACTORS PICKUP TRUCKS, LIGHT-DUTY TRUCKS, HEAVY-DUTY TRUCKS AND A FEW MISCELLANEOUS VEHICLES. TWENTY-TWO VEHICLES WERE OPERATED ON NONLEADED REGULAR-GRADE GASOLINE AND 30 VEHICLES WERE OPERATED ON LEADED REGULAR-GRADE GASOLINE. EACH MONTH FROM AUGUST 1971 THROUGH MAY 1972, MEASUREMENTS OF TEMPERATURE, HUMIDITY, MILEAGE, AIR-FUEL RATIO AND EMISSIONS OF TOTAL HYDROCARBONS AND CARBON MONOXIDE WERE RECORDED FOR EACH VEHICLE UNDER NO-LOAD CONDITIONS AT IDLE AND AT 2500 RPM. TEN PAIRS OF VEHICLES WERE SELECTED FROM THE TEST FLEET. EACH PAIR WAS MATCHED ACCORDING TO TYPE, MAKE AND MILEAGE AS CLOSELY AS POSSIBLE. THE MAJOR DIFFERENCE IN EACH PAIR WAS FUEL: ONE VEHICLE USED LEADED FUEL, THE OTHER USED NON-LEADED FUEL. EMISSION MEASUREMENTS YIELDED STATISTICALLY SIGNIFICANT (95% CONFIDENCE LEVEL) DIFFERENCES BETWEEN LEADED AND NONLEADED GASOLINE. LOWER HC AND CO EMISSIONS EXISTED FOR LEADED GASOLINE WHEN FLEET VEHICLES WERE TESTED UNDER NO-LOAD CONDITIONS. AIR-FUEL RATIO CAUSED LARGER DIFFERENCES IN MEASURED EMISSIONS THAN DIFFERENCES IN TYPE OF GASOLINE. WHEN THE MATCHED PAIRS WERE TESTED UNDER LOAD, THE LEADED FUEL YIELDED SIGNIFICANTLY HIGHER HC EMISSIONS FOR PICKUPS AND HEAVY-DUTY TRUCKS AS WELL AS HIGHER CO EMISSIONS WITH LIGHT-DUTY TRUCKS. HOWEVER, THIS WAS MAINLY TRUE AT FULL LOAD AT WHICH THE VEHICLES WOULD RARELY OPERATE. ENGINE ADJUSTMENT WAS FOUND TO BE CONSIDERABLY MORE IMPORTANT IN CONTROLLING EXHAUST EMISSIONS THAN WAS THE TYPE OF FUEL USED. NO SIGNIFICANT DIFFERENCES DUE TO GASOLINE WERE OBSERVED IN EITHER MAINTENANCE COSTS, FUEL CONSUMPTION, OR RESIDUE IN OIL DURING THE COURSE OF THIS STUDY. RECOMMENDATIONS FROM THIS STUDY ARE: (1) CONTINUE USE OF LEADED FUEL IN ALL VEHICLES FOR WHICH THE TEST FLEET IS INDICATIVE; (2) ESTABLISH REGULAR TUNE-UP SCHEDULES USING EXHAUST EMISSION EQUIPMENT; (3) INITIATE AN EASILY ACCESSIBLE RECORD KEEPING SYSTEM FOR CONSUMPTION AND MAINTENANCE ITEMS; (4) USE CERTIFIED REFERENCE GASES TO CALIBRATE ALL EMISSION MEASURING EQUIPMENT; (5) EXTEND THE STUDY FOR THE LIFETIME OF THE VEHICLES UNDER TEST SO THAT EFFECTIVE COMPARISONS CAN BE MADE ON MAINTENANCE ITEMS AND FUEL AND OIL CONSUMPTION; AND (6) PREVENT OVER SPECIFICATION OF ENGINE SIZE ACTUALLY NEEDED WHEN PURCHASING NEW VEHICLES. /AUTHOR/

• Supplemental Notes:
  • ISU-ERI-AMES-72/84 14 APP
• Corporate Authors:

  Iowa State University, Ames

  2711 South Loop Drive
  Suite 4700
  Ames, IA  United States  50010-8664
• Authors:
  • HALL, J
  • Bathie, W W
  • Van Meter, D B
• Publication Date: 1972-7

Media Info

• Features: References; Tables;
• Pagination: 63 p.

Subject/Index Terms

• TRT Terms: Air pollution; Air quality management; Emotions; Engines; Fuel consumption; Fuels; Gasoline; Maintenance management; Pollutants; Trucks
• Uncontrolled Terms: Maintenance costs
• Old TRIS Terms: Emission rates
• Subject Areas: Energy; Highways; Motor Carriers; Safety and Human Factors; Vehicles and Equipment;

Filing Info

• Accession Number: 00224466
• Record Type: Publication
• Report/Paper Numbers: Final Rept
• Files: TRIS
• Created Date: Jan 31 1974 12:00AM