NTRD-02 Final Project Report The Effects of Low Rolling Resistance ...

5 J1321 TRACK TESTS AND RESULTS
The new Texas Drayage Truck Test Cycle was used to evaluate low-mass low-rolling resistance
tires on representative trucks in the SAE J1321 “Joint TMC/SAE Fuel Consumption Test
Procedure Type II”. The test program was designed to evaluate both the fuel economy and the
NOx impact of using the wide-single tires on drayage trucks while hauling chassis with
corresponding containers. The test trucks were model year 2006 Freightliner Class 8 trucks with
Detroit Diesel engines. In addition to gravimetric fuel tanks for measuring fuel economy, a
Portable Emissions Monitoring System (PEMS) was installed in each truck to measure NOx.
The PEMS units were Sensors, Inc. SEMTECH-D instruments.
The J1321 recommended practice provides a standard test procedure for comparing the inservice
fuel consumption of a vehicle operating under two conditions: a test and a baseline. An
unchanging control vehicle is run in tandem with a test vehicle to provide an unchanging
reference. The result of a test using this procedure is the percentage difference in fuel
consumption or NOx emissions of the test vehicle in two different test configurations.
The program setup is discussed in Section 5.1, the testing is discussed in Section 5.2, and the
results from the track tests are presented in Section 5.3. A complete record of the track testing is
available in Shoffner et al. (2007).
5.1 Program Setup
Two truck and chassis/container combinations (each one designated a truck and trailer “rig”)
were used for testing. The trucks were chosen to be as close to each other as possible in
construction, age, and usage history. Note the similar VIN numbers and engine serial numbers in
the specifications and data for the trucks, chassis trailers, and containers shown in Table 2. A
photograph of one of the truck and trailer rigs is provided in Figure 9.
Table 2. Specifications of the Control and Test Rigs.
Name “Control” “Test”
Truck Ser. No. 509338 509340
Truck VIN 1FUJA6CK87DX33832 1FUJA6CK17DX33834
Truck manufacturer Freightliner Freightliner
Engine manufacturer Detroit Diesel Detroit Diesel
Engine
Series 60/14.0 L Series 60/14.0 L
model/displacement
Engine emissions family 6DDXH14.0ELY 6DDXH14.0ELY
Engine Ser. No. 06R0902859 06R0904064
PEMS No. SEMTEC-D-G04-SD03 SEMTEC-DS E06-SDS01
Chassis (trailer) No. FLXZ402881 FLXZ401251
Container No. 5877886 5069635
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