1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW14380 Thermal Shock Cycle Test for Exhaust System Tuning Elements Copyright 2011 General Motors Company All Rights Reserved September 2011 Originating Department: GME Specification Center Page 1 of 6 1 Scope Note: Nothing in this standard supercedes
2、 applicable laws and regulations. Note: In the event of conflict between the English and domestic language, the English language shall take precedence. 1.1 Purpose. To prove the structural durability of tuning elements against thermal cycling caused by varying exhaust gas temperatures as well as by
3、external water splash on the hot tuning element surface. 1.2 Foreword. Not applicable. 1.3 Applicability. This test procedure is applicable to all exhaust system tuning elements. It may also be applied to other exhaust system components (e.g. heat shields attached to exhaust pipes, exhaust gas heat
4、recovery units). In such a case required modifications of the test set up, test conditions and test criteria shall be defined in the components specification. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. None
5、2.2 GM Standards/Specifications. GMW14555 GMW15261 GMW16372 2.3 Additional References. 3 Resources 3.1 Facilities. 3.1.1 Hot gas test bench with thermal control cycle and controllable water-spray unit. 3.2 Equipment. 3.2.1 Hot Gas Burner. A switchable hot gas burner capable of providing the required
6、 gas mass flow rate at the gas temperature as specified in paragraph 3.5.1. 3.2.2 Water Spray Device. A water spray device capable of providing the required water flow rate and water spray distribution on the test sample. Recommended water flow rate per nozzle is 3 l/minute. 3.2.3 Sensors. 3.2.3.1 T
7、emperature Sensors. The temperature sensor shall cover the expected temperature range at an accuracy of 1 %. Recommended are thermocouples Type K, Tolerance Class 2, or equivalent. 3.2.4 Data Acquisition Equipment. 3.2.5 Restriction Measurement Test Bench. A cold flow test bench is required to deter
8、mine the tuning elements restriction. A GM-approved specification for the test bench is described in GMW16372. Alternative test facilities may also be used but require the approval of the GM validation engineer or GM design release engineer. 3.3 Test Vehicle/Test Piece. New test samples shall be use
9、d. For product validation testing off-tool parts are mandatory. For design validation testing prototype parts may be used. If a heat shield is attached to the tuning element the complete tuning element assembly including heat shield shall be tested. Copyright General Motors Company Provided by IHS u
10、nder license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14380 Copyright 2011 General Motors Company All Rights Reserved September 2011 Page 2 of 6 3.4 Test Time. Calendar time: 3 days Test hours:
11、 50 h Coordination hours: 2 h The actual test duration is dependent on specific test conditions. 3.5 Test Required Information. 3.5.1 Test Temperature. 3.5.1.1 Surface Temperature Measurement Location. The temperature shall be measured on the outer surface of the tuning element. In particular the te
12、mperature shall be determined in the area that is expected to see the highest surface temperatures. The measurement location shall be selected under consideration of the tuning element internal design. The GM design release engineer or validation engineer shall agree to the selected location. 3.5.1.
13、2 Surface Test Temperatures. The maximum surface test temperature during the heating cycle shall be equal to the maximum surface temperature that is being measured at the specified location during any continous driving condition according to GMW14555. Excursion driving events in GMW14555 shall not b
14、e considered. If the above described temperature measurement is not readily available the maximum surface test temperature shall be defined based on experimental thermal data from previous applications that are most similar with regard to exhaust gas temperature, exhaust gas mass flow and exhaust sy
15、stem design. Alternatively exhaust system thermal predictive analysis may be used to define the most appropriate test temperature. The minimum surface temperature during cooling cycle shall be +100 C. Design release engineer and validation engineer shall mutually agree on the test temperatures. 3.5.
16、1.3 Inlet Gas Temperature. The heating cycle tuning element inlet gas temperature shall be based on the same driving schedule the maximum surface test temperature is based on. It shall be equal to the maximum exhaust gas temperature at the tuning element inlet measured during this driving schedule.
17、If this information is not available for the specified vehicle application, the temperature shall be defined based on data of a comparable vehicle application or on exhaust system thermal predictive analysis. The cooling cycle tuning element inlet gas temperature shall be +50 C. 3.5.1.4 Gas Flow. Th
18、e test gas flow shall be 250 kg/h. For reproducible test results the test gas flow shall be kept constant when testing several samples of the same part. 3.5.2 Tuning Element Location and Orientation. Math data, showing tuning element location and orientation in the vehicle, shall be provided to the
19、test engineer. 3.5.3 Leakage Requirements. Allowable leakage of the test piece per Exhaust Subsystem Technical Specification (SSTS), paragraph 3.2.1.1.2. 3.6 Personnel/Skills. Not applicable. 4 Procedure 4.1 Preparation. 4.1.1 Test Set up. Figure 1 illustrates the test set up. Copyright General Moto
20、rs Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14380 Copyright 2011 General Motors Company All Rights Reserved September 2011 Page 3 of 6 Figure 1: Test Set u
21、p 4.1.1.1 Water Spray Device. The test sample shall be subjected to water according to its location in the vehicle. Usually the lower half of a tuning element is exposed to water spray. The water spray nozzles shall be installed accordingly. Figure 2 is showing the recommended water spray device con
22、figuration. In order to cover the entire test sample several rows of nozzles may needed to be installed around the test sample. The recommended nozzle flow rate is 3 l/minute. Figure 2: Water Spray Nozzle Configuration 4.1.1.2 Test Sample Installation. The test sample orientation on the test bench s
23、hall be the same as within the vehicle. Any deviation needs to be approved by the design release engineer and the validation engineer. 4.2 Conditions. 4.2.1 Environmental Conditions. Test chamber temperature shall be (+23 5) C. 4.2.2 Test Conditions. Deviations from the requirements of this standard
24、 shall have been agreed upon. Such requirements shall be specified on component drawings, test certificates, reports, etc. 4.3 Instructions. 4.3.1 Determination of Tuning Element Restriction. Before conducting the thermal cycle test the tuning elements restriction shall be measured per GMW16372 or e
25、quivalent. Alternative test methods are acceptable if agreed by GM. It shall be noted that the purpose of this measurement is to determine a reference value for the restriction measurement which is conducted after the thermal cycles. This reference measurement may deviate from the actual restriction
26、 target of the tuning element. 4.3.2 Thermal Cycle. The test sample shall be subjected to hot gas via the inlet pipe until the specified surface test temperature is reached. The tuning element outer surface shall then be cooled by the means of water spray in 5 one-minute spray intervals. Each water
27、spray interval will consist of 10 s of water spray followed by a 50 s break. This will continue for a total of 5 water spray intervals. The test sample shall then be subjected to the cooling gas blown in via the inlet pipe as shown in Figure 1. The cooling gas shall be air at the temperature specifi
28、ed in paragraph 3.5.1.3. This cooling cycle shall be continued until the minimum surface temperature is being achieved. The sequence of events as described above shall constitute one thermal shock test cycle as shown in Figure 3. Copyright General Motors Company Provided by IHS under license with Ge
29、neral Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14380 Copyright 2011 General Motors Company All Rights Reserved September 2011 Page 4 of 6 Figure 3: Test Cycle T Surface, max: Maximum surface test temperatur
30、e T Surface, min: Minimum surface test temperature T Gas, heating: Heating cycle test sample inlet gas temperature T Gas, cooling: Cooling cycle test sample inlet gas temperature 4.3.3 Thermal Cycle Duration. The duration of the cooling cycle may be expanded in order to adapt the cycle times to the
31、need of the test bench. This variation of the test procedure shall support the parallel testing of two test samples. 4.3.4 Number of Thermal Cycles. A total of 120 thermal test cycles are expected to represent a total vehicle mileage of 160 000 km (100 000 miles). If the actual vehicle program milea
32、ge requirement deviates from this value the number of test cycles shall be adapted accordingly. 4.3.5 Leakage Test. After completion of all thermal test cycles the leak rate of the tuning element shall be determined according to GMW15261. 4.3.6 Determination of Tuning Element Restriction. The tuning
33、 elements restriction shall be measured per GMW16372 or equivalent. Alternative test methods are acceptable if agreed by GM. The purpose of this measurement is to identify the difference in restriction compared to the reference measurement as described in paragraph 4.3.2. 4.3.7 Visual Inspection of
34、the Outer Tuning Element Shell. After completion of the leakage test the test sample shall be inspected for severe deformations of the outer tuning element shell. For documentation photographs shall be taken. If a heat shield is attached to the tuning element it shall be inspected for cracks and pro
35、per attachment to the tuning element. 4.3.8 Functional Test. Test samples that include an actuator like a valve require a functional test. The function shall be tested per the corresponding exhaust system or component specification. 4.3.9 Tuning Element Internals. The test sample shall be examined f
36、or rattling noises. The purpose is to identify any loose parts inside of the tuning element. In addition the test sample shall be cut and the inner shell and all internal components shall be inspected. The following items require special attention: a. Welded joints and mechanical connections. b. Pos
37、ition of baffles, potential displacement of the baffles. c. Deformations of the pipe and the perforation. d. Compacting of the absorption material. e. Implosion of an inner shell. f. Valves and other actuators. Copyright General Motors Company Provided by IHS under license with General Motors Compan
38、yNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14380 Copyright 2011 General Motors Company All Rights Reserved September 2011 Page 5 of 6 5 Data 5.1 Calculations. Not applicable. 5.2 Interpretation of Results. The thermal sho
39、ck cycle test shall be regarded as having been passed if the tuning element continues to meet its requirements with regard to functional performance e.g. leakage, restriction, noise and vibration. 5.2.1 Leak Rate. The maximum tuning element leak rate as specified in the exhaust SSTS shall not be exc
40、eeded. 5.2.2 Tuning Element Restriction. Restriction, mass flow rate, and gas temperature should be recorded and compared, before and after test. The restriction of the tuning element after the thermal cycle test shall not have increased by more than 5 % compared to the reference measurement conduct
41、ed before the test. 5.2.3 Outer Tuning Element Shell. Deformations of the tuning element shell are permissible as long as the function of the tuning element is not impaired. Heat shields attached to the tuning element must not have any cracks and must not be loose. 5.2.4 Valves and Actuators. Functi
42、onal requirements shall be met per SSTS specification. 5.2.5 Tuning Element Internals. Fractures or cracks of any tuning element internal part or of any weld seam are not permissible. Any deformation of an internal part that is critical to the acoustic performance or the tuning element restriction i
43、s not permissible. 5.3 Test Documentation. 5.3.1 Summary of Test Results and Rating. Overall rating of test results (OK, NOK) shall be shown on the first page. The test specification as well as any deviation from this procedure shall be described. 5.3.2 Test Piece Description. Part name and number,
44、development status, date of manufacture, drawing number, drawing revision, drawing date and photograph. 5.3.3 Test Description. Description of test facility and test set up with photographs, calibration of test equipment, and ISO certificate of test facility. 5.3.4 Individual Results. The test condi
45、tions and all recorded data shall be included in the report. Determined leak rate and restriction, before and after the test, shall be documented and compared with the requirements. Photographs of the test sample after the test shall be included. Damages of any part shall be described in detail with
46、 the help of photographs. 6 Safety This standard may involve hazardous materials, operations, and equipment. This standard does not propose to address all the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health pra
47、ctices and determine the applicability of regulatory limitations prior to use. 7 Notes 7.1 Glossary. 7.2 Acronyms, Abbreviations, and Symbols. I S O International Organization for Standardization OK Approved or Endorsed NOK Not Approved or Endorsed SSTS Subsystem Technical Specification VTS Vehicle
48、Technical Specification 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Test to GMW14380 Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license f
49、rom IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14380 Copyright 2011 General Motors Company All Rights Reserved September 2011 Page 6 of 6 9 Release and Revisions This standard was originated in October 2005. It was first approved by Global Exhaust SSLT in November 2005. It was first published in November 2005. Issue Publication Date Description (Organization) 1 NOV 2005 Initial publication. 2 SEP 2011 Paragraph
