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. 2018 by Navistar, Inc. FEBRUARY 2018 Page 1 of 7 NAVISTAR, INC. Material, Parts, and Process Specificati
2、ons (MPAPS) NUMBER: MPAPS FT-1 Former Designation: CEMS FT-1 TITLE: HVAC-TXV Durability Testing CURRENT REV No.: 1802 DATE: Feb. 2018 WRITTEN/EDITED BY: W. Cook APPROVED BY: R. Goluch SUPERSEDES: Rev. June 2012 PRINTED COPIES OF THIS DOCUMENT MUST BE VERIFIED FOR CURRENT REVISION This specification
3、may involve hazardous 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
4、. 1.0 APPLICATION Thermal Expansion Valves (TXV) mounted on rear auxiliary HVAC units typically located in the sleeper area of a cab 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 auxi
5、liary HVAC unit. 2.0 REFERENCE DOCUMENTS Unless otherwise specified the latest issue of all referenced standards shall apply. The following specifications and standards are referenced in this specification: NAVISTAR MPAPS P-9543 WRTS 02-6402 NAVISTAR MPAPS F-6021 WRTS 12-37282 2.1 Definitions 2.1.1
6、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 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
7、 and amplitude requirements for the tested vocational inputs. 3.2 Pressure gages and/or transducers to monitor the pressure on each side (high and low) of the test article(s) NUMBER: MPAPS FT-1 TITLE HVAC-TXV Durability CURRENT ISSUE REV: 1802 This document is restricted and may not be sent outside
8、Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2018 by Navistar, Inc. FEBRUARY 2018 Page 2 of 7 4.0 TEST PREPARATION(S) 4.1 Test Fixturing A fixture should be created/used that can act as an attachment betwee
9、n the shaker and the TXV. This fixture should be capable of orienting the TXV (and its associated piping) in all three vehicle directions (Longitudinal, Lateral, and Vertical) without removing the TXV or disturbing its fasteners. Figures 1 thru 3 show examples of a fixturing design that accomplishes
10、 this. Additionally, a setup should be created to directly monitor both the high and low side pressures of each individual test article throughout 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. Typical
11、ly, 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 allowed 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 producti
12、on representative vehicle of the correct vocation. Once this data has been collected, a frequency response or “break point” table shall be created 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 exampl
13、e 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 corresponding 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
14、the prescribed torque. 5.2 Pressurize the test article(s) to the prescribed vehicle pressures. Typically used gases include air and nitrogen. 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 R
15、EMOVE THE PIPES FROM THE TXV OR RELEASE THE PRESSURE DURING THE POSITION CHANGES! 5.5 Once all three orientations are complete, allow the TXV 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
16、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 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 unt
17、il the original torque value is reached, whichever comes first. c. Record the value. 5.7 Acceptance Criteria a. No leakage of the pressurized 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 o
18、f the test. NUMBER: MPAPS FT-1 TITLE HVAC-TXV Durability CURRENT ISSUE REV: 1802 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. 2018 by Navistar, Inc. F
19、EBRUARY 2018 Page 3 of 7 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 the requirements of MPAPS P-9543. NUMBER: MPAPS FT-1 TITLE HVAC-TXV Durability CURRENT ISSUE REV: 1802 This document is restricted and may not b
20、e sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2018 by Navistar, Inc. FEBRUARY 2018 Page 4 of 7 Figure 1: TXV mounted to shake along the vehicle-vertical direction NUMBER: MPAPS FT-1 TITLE HVAC
21、-TXV Durability CURRENT ISSUE REV: 1802 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. 2018 by Navistar, Inc. FEBRUARY 2018 Page 5 of 7 Figure 2: TXV mo
22、unted to shake along the vehicle-lateral direction NUMBER: MPAPS FT-1 TITLE HVAC-TXV Durability CURRENT ISSUE REV: 1802 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 pat
23、ent liability. 2018 by Navistar, Inc. FEBRUARY 2018 Page 6 of 7 Figure 3: TXV mounted to shake along the vehicle-longitudinal direction NUMBER: MPAPS FT-1 TITLE HVAC-TXV Durability CURRENT ISSUE REV: 1802 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without pe
24、rmission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2018 by Navistar, Inc. FEBRUARY 2018 Page 7 of 7 Table 1: Example of the LH1 Frequency Response Table (from WRTS 12-37282) Direction Cycles Freq (Hz) Level (g) X - Long 10,500 2 2,300 7.0 2.5 700 3 48
25、 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 REVISION HISTORY Revision Level Change Approved by Date Approved 1802 Converted to MPAPS; Editorial Changes R. Goluch 2/13/2018
