1、 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2012 by Navistar, Inc. JUNE 2012 Page 1 of 6 NAVISTAR, INC. CEMS (CORPORATE ENGINEERING MATERIAL SPECIFI
2、CATION) NUMBER: CEMS FT-1 TITLE: HVAC-TXV Durability Testing CURRENT ISSUE DATE: June 2012 WRITTEN/REVIEWED BY: Materials Engineering APPROVED BY: Materials Engineering SUPERSEDES ISSUE OF: N/A PRINTED COPIES OF THIS DOCUMENT MUST BE VERIFIED FOR CURRENT REVISION This specification may involve hazar
3、dous materials, equipment, and procedures. This specification does not purport to address all of the safety issues associated with its use. The user is responsible to consult appropriate safety and health practices and to determine the applicability of regulatory limits prior to use. Change Notice:
4、NEW 1.0 SCOPE This method is to define the procedure for testing the mechanical vibration durability of the Thermal Expansion Valve (TXV) as it is mounted on the rear auxiliary HVAC unit. 2.0 REFERENCE DOCUMENTS Unless otherwise specified the latest issue of all referenced standards shall apply. The
5、 following specifications and standards are referenced in this specification: NAVISTAR TMS-9543 Work Request 02-6402 NAVISTAR TMS-6021 2.1 Definitions 2.1.1 Terminology 2.1.1.1 Rear Auxiliary Unit A secondary HVAC module that is typically located in the sleeper area of a cab. 2.1.2 Acronyms/Symbols
6、2.1.2.1 HVAC Heating/Ventilation/Air Conditioning 2.1.2.2 TXV Thermal Expansion Valve 3.0 APPARATUS 3.1 A single-axis shaker capable of meeting the frequency and amplitude requirements for the tested vocational inputs. 3.2 Pressure gages and/or transducers to monitor the pressure on each side (high
7、and low) of the test article(s) 4.0 TEST PREPARATION(S) 4.1 Test Fixturing A fixture should be created/used that can act as an attachment between the shaker and the TXV. This fixture should be capable of orienting the TXV (and its associated piping) in all three vehicle directions (Longitudinal, Lat
8、eral, and Vertical) without removing the TXV or disturbing its fasteners. Figures 1 thru 3 show examples of a fixturing design that accomplishes this. NUMBER: CEMS FT-1 TITLE HVAC-TXV Durability CURRENT ISSUE DATE: June 2012 This document is restricted and may not be sent outside Navistar, Inc. or r
9、eproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2012 by Navistar, Inc. JUNE 2012 Page 2 of 6 Additionally, a setup should be created to directly monitor both the high and low side pressures of each individual test article throug
10、hout the testing. 4.2 Test Article(s) The TXV should be sealed in such a manner that each side of the valve can maintain its own independent pressure. Typically, a thin plate of metal is sealed to the back of the block during this process. Once sealed, each tested valve should be pressurized and all
11、owed to rest (sometimes referred to as “soaking”) for 24 hours to be sure it can maintain pressure. 4.3 Test Data Test data should be gathered from a production representative vehicle of the correct vocation. Once this data has been collected, a frequency response or “break point” table shall be cre
12、ated for each orthogonal direction. A procedure for creating such a table can be found in the report for Work Request 02-6402. Table 1, below, shows an example of such a table used on a TXV shaker for a ProStar Sleeper cab with the Line Haul #1 (LH1) vocation. This data is used to set up the corresp
13、onding shaker program(s). 5.0 PROCEDURE 5.1 Connect the test article(s) to the shaker via the fixturing. Use the prescribed O-rings and fasteners, as well as the prescribed torque. 5.2 Pressurize the test article(s) to the prescribed vehicle pressures. Typically used gases include air and nitrogen.
14、5.3 Perform the shaker program corresponding to the installed orientation. 5.4 Repeat steps 1 and 2 until all three orientations have been performed. DO NOT REMOVE THE PIPES FROM THE TXV OR RELEASE THE PRESSURE DURING THE POSITION CHANGES! 5.5 Once all three orientations are complete, allow the TXV
15、to remain attached to the fixture in the position of its last run, and allow the TXV to soak for 16 hours to see if any slow leaks have developed. 5.6 At the end of the soak, prior to disassembly, check and record the torque of the nut that holds the hose clamping plate to the TXV block: a. Set the
16、value of the torque wrench to the same value used to tighten the nut down. b. Advance the nut in the tightening direction until relative motion occurs, or until the original torque value is reached, whichever comes first. c. Record the value. 5.7 Acceptance Criteria a. No leakage of the pressurized
17、gas shall occur between the beginning of the test and the end of the 16-hour soak period. b. No damage or cutting of the o-rings shall be present at the end of the test. 6.0 REPORT 6.1 Materials Tested 6.2 An itemized parts list 6.3 Assembly conditions 6.4 Fluids used 6.5 All test reports shall meet
18、 the requirements of TMS-9543. NUMBER: CEMS FT-1 TITLE HVAC-TXV Durability CURRENT ISSUE DATE: June 2012 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability.
19、2012 by Navistar, Inc. JUNE 2012 Page 3 of 6 Figure 1: TXV mounted to shake along the vehicle-vertical direction NUMBER: CEMS FT-1 TITLE HVAC-TXV Durability CURRENT ISSUE DATE: June 2012 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corp
20、orate Technical Standards. Suppliers are required to assume all patent liability. 2012 by Navistar, Inc. JUNE 2012 Page 4 of 6 Figure 2: TXV mounted to shake along the vehicle-lateral direction NUMBER: CEMS FT-1 TITLE HVAC-TXV Durability CURRENT ISSUE DATE: June 2012 This document is restricted and
21、may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2012 by Navistar, Inc. JUNE 2012 Page 5 of 6 Figure 3: TXV mounted to shake along the vehicle-longitudinal direction NUMBER: CEMS FT-1 TI
22、TLE HVAC-TXV Durability CURRENT ISSUE DATE: June 2012 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2012 by Navistar, Inc. JUNE 2012 Page 6 of 6 Table
23、1: Example of the LH1 Frequency Response Table Direction Cycles Freq (Hz) Level (g) X - Long 10,500 2 2,300 7.0 2.5 700 3 48 Min 10,500 2 2,300 14.0 2.5 700 3 Y - Lat 9,000 1.5 1,200 6.5 2 300 2.5 46 Min 9,000 1.5 1,200 9.0 2 300 2.5 Z - Vert 5,000 2 1,000 6.0 2.5 300 3 33 Min 5,000 2 1,000 7.0 2.5 300 3
