1. Define protocol details associated with the test for fuel efficiencies using Cognis FE 75W-90 axle lube. What are SAE protocols for testing?

The procedure chosen for this evaluation was the SAE Joint TMC/J1321 "SAE Fuel Consumption Test Procedure - Type II" which was developed to specifically meet the needs of the trucking industry. This recommended practice provides a standardized test procedure for comparing the in-service fuel consumption of a vehicle operated under two conditions. An unchanging control vehicle is run in tandem with a test vehicle to provide reference fuel consumption data. The result of a test using this procedure is the percent difference in fuel consumption of one truck in two different test conditions. A total of two trucks were used (1 control truck and 1 test truck).

2. Trucks configuration?

The control and test vehicles used during the test program were 2007 Internationals, Model 9400. The vehicles were equipped with Caterpillar C15 ACERT engines rated at 466 hp at 2100 rpm. The transmission in each truck was a Eaton Fuller FR0-16210C and the drive axles were Dana Spicer DS404 with 3.36 to 1 ratios. The vehicles had been operated between 15,000 and 30,000 miles prior to being used. The control truck was identified as Unit 61 and the test truck was identified as Unit 67. The test truck was the higher mileage truck. The research facility rented identical trailers and ballasted the 48-foot flat beds with concrete blocks to a gross vehicle weight (GVW) of approximately 76,000 lbs.

3. Truck preparation?

• All the wheels of the trucks and trailers were aligned.
• The engine air filters and fuel filters of the trucks were replaced.
• The engine oil and oil filters were changed at the beginning of the test on both trucks.
• All components having an aerodynamic influence were set to a consistent position among all trucks.
• A gravimetric fuel measurement system was connected to each truck’s fuel system via quick coupling devices to permit operation either from the vehicle’s fuel supply or from the gravimetric fuel source.
• The driver and observer teams conducted practice laps to establish target times at mile markers on the route. The target times were specific to the driver and the tractor/trailer rig. During the testing phase, the lap time must be within +/-0.5% of the target time to be considered operationally valid.

4. Test Route?

The test route chosen represented typical long-haul interstate highway operations. A low-density traffic portion of IH10 was used between the Ralph Fair Road exit and the 527 Waring exit. Each lap was started by traveling west from Ralph Fair Road to the 527 Waring exit. The trucks exited at the Waring exit then crossed the interstate to begin the second half of the route eastbound. The road surface was asphalt and the terrain was generally flat with some rolling hills.

The trucks were then driven 23 miles from the research facility to the beginning of the test route. One lap was run as a warm-up each day prior to measuring fuel consumption. Ambient temperature and wind speed were recorded prior to each lap. The trucks ran the route with 5 minutes separation between the control truck and the test truck. The same drivers operated their assigned trucks throughout the test program.

Fuel use was measured over a distance of 46 miles, 23 miles westbound and 23 miles eastbound. The westbound leg began on the shoulder of IH10 service road west of IH10 Ralph Fair Road at a designated landmark. The engines were stopped and the fuel supply and return lines were switched from the truck tanks to the first weigh tank. The engines were restarted, a stopwatch was activated, and the trucks accelerated to a cruising speed of 60 mph. The cruising speed was maintained for 23 miles. After 23 miles, the trucks exited IH10 at the Waring exit. The trucks were driven across IH10 and re-entered IH10 heading east. The trucks accelerated to a cruising speed of 60 mph for 23 miles and exited IH10 at the Ralph Fair Rd. exit. The trucks pulled off the shoulder on the IH10 service road at a designated landmark and idled for 60 seconds, and then the engines were stopped. The fuel lines were then switched from the weigh tank to the truck tanks. The trucks were driven back to the westbound IH 10 service road starting point and the process was repeated two more times for a total of three weigh tanks/laps. Because of the long distance between the research facility and the test route, the trucks would attempt to complete three laps each day before returning back to the research facility.

To maintain consistent operation, the trucks were operated with the headlights on (low beam) and the A/C or heater blower off. The drivers coordinated the window openings so that all the trucks had their windows in the same position during the test laps.

5. What are the margins of accuracy for the test?

A datalogger was installed in each truck to record the CAN J1939 data stream, along with ambient temperature, oil sump temperature of the engine, transmission and drive axles. These data were reduced in plots to show miles per hour, ambient, transmission oil, and both axle differential temperatures

The quantity (weight) of fuel used by the control truck is compared to the weight of fuel used in the test truck. This is done by calculating a ratio of the weight of fuel used between the control truck and the test truck. The weight of fuel used by the test truck is divided by the weight of fuel used by the control truck. The J1231 procedure identifies this number as the T/C ratio. After three runs have been completed, the T/C ratios are tested for repeatability by multiplying the highest T/C ratio by 0.98 to establish the lowest acceptable T/C ratio which would be within 2% of the highest ratio. When three runs have been completed with T/C ratios within 2%, the baseline or test segment is complete. The average of the three T/C ratios is used to calculate the test results (percent fuel saved).

If the test truck did not have a set of three T/C ratios that were within 2% of each other after the first attempt, the truck was driven for three more laps each day until the truck had three laps where the T/C ratios were within the 2% range. The T/C ratios chosen for the % fuel saved and % improvement calculations were based on the first matches that occurred chronologically.

The results of these calculations have ±1% error bars on each data point to show that the results have a procedure accuracy of ±1%. For example, a data point (result) of 1% could really be anywhere between 0% and 2%.

 6. Test Summary