Cover Image

Not for Sale



View/Hide Left Panel
Click for next page ( 23


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 22
22 Table 2. Tests of the 4400 truck with Table 3. Tests of the 9200i truck at the speaker at the low-speed track. low-speed track. Speed (mph) rpm Gear Speaker Speed (mph) rpm Gear Notes 0 (stationary) idle Neutral Off/On 0 Idle Neutral 0 (stationary) 2000 Neutral Off/On 0 650 Neutral Stationary 18 1500 2nd Off/On 0 1200 Neutral 25 2000 2nd Off/On 0 1800 Neutral 31 2500 2nd Off/On 15 1200 6th Constant rpm, 27 Cruise 4th Off 25 1200 7th varied gear 30 1200 8th 13 650 7th Constant gear, 20 1200 7th varied rpm revolutions per minute, and gear settings used for the truck 31 1850 7th 29 Coast down Neutral runs are summarized in Table 2. 29 Cruise 7th The next truck tested at the low-speed track was an Inter- Acceleration 700 7th national 9200i Eagle truck (2006 model year). This is a heavy- duty truck used for long hauls. It was powered with a Cummins ISX 450 hp engine and had a single horizontal muffler and a used in the testing. The truck is shown in Figure 17. The truck vertical tailpipe, which was mounted to the rear passenger side test conditions are listed in Table 4. of the cab. The truck tractor with no trailer was used, equipped The measurement data collected during the testing at IT's with eight Goodyear G372 tires on tandem drive (rear) axles low-speed track were preliminarily reviewed in the labora- and two Goodyear G395 tires on the steer (front) axle. The tory the following week and determined suitable for full truck was also equipped with aero skirts under the cabin. The post-processing and analysis. The key results of the analysis are truck is shown in Figure 16. The truck tests, performed with no presented and discussed in Section 3.5. The microphone array loudspeaker, are summarized in Table 3. and data acquisition system performed as expected and The testing then continued with the third truck, an Interna- required no major adjustments for the next stage of the proof- tional 5900 PAYSTARTM (2004 model year), which is a "severe of-concept testing at IT's high-speed endurance track. service" truck designed to have other equipment mounted on the frame, such as a concrete-mixer drum and associated 3.4.2 High-Speed Tests equipment, and to be used with very heavy payloads. It was powered with a Cummins ISX 565 hp engine. For these tests, For high-speed testing, the microphone array and data the truck had dual vertical mufflers and tailpipes mounted to acquisition system were transported to IT's endurance track. the back sides of the cab. Only the truck tractor was driven, It consists of a 1 mi (0.6 km) long multiple-lane loop designed with approximately 7000 lbs of weight added on the rear sec- for conducting long-term truck testing with a maximum speed tion of the tractor frame. There were eight Goodyear G167 tires limit of 50 mph (80 km/h). The microphone array was placed on tandem drive (rear) axles and two Goodyear G287 tires on in the sealed asphalt area along the middle part of the track, at the steer (front) axle. In this case again, a loudspeaker was not Figure 17. The 5900 truck in front of microphone Figure 16. The 9200i truck at the low-speed track. array at the low-speed track.