Method for evaluating and testing cold and hot impact resistance of three-way catalyst of passenger car
Through simple thermal shock mounts, the extreme environment of the engine is simulated, and the cold and cold impact resistance of the three-way catalyst is quickly evaluated, solving the problems of long verification cycles and insufficient accuracy in the existing technology, and achieving efficient and accurate performance evaluation.
Patent Information
- Application Number
- CN202411304992.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-19
- Publication Date
- 2025-01-03
AI Technical Summary
The prior art is difficult to quickly and accurately evaluate the cold and cold impact resistance of passenger vehicle three-way catalysts. The traditional road durability test verification cycle is long and affected by the environment, so it is impossible to fully simulate extreme environments, resulting in high verification costs and inaccurate results.
Using simple thermal shock mounts to simulate the extremely high and low temperature conditions of the engine, hot and cold shock tests are carried out through thermocouple settings and vibration tables and other equipment to quickly judge the performance of the parts of the three-way catalyst, including preheating, setting conditions and Test parameters to determine the failure of the carrier, shell and gasket.
It greatly shortens the verification cycle, reduces equipment and site requirements, saves costs, can accurately simulate extreme environments, and improves the accuracy of test results.
Smart Images
Figure CN119246591A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of automobiles, and in particular to a method for evaluating and testing the cold and hot shock resistance performance of a three-way catalytic converter of a passenger car. Background Art
[0002] The engine three-way catalytic converter is installed close to the exhaust side of the engine. Its main structure is the packaging shell, gasket, and three-way carrier. The main function of the three-way carrier is to purify the exhaust gas, and it is tightly wrapped by the packaging shell and gasket.
[0003] The working conditions of the three-way catalytic converter are extremely harsh and demanding. While bearing the high-temperature gas of the engine, it is also impacted by the external low-temperature environment. Under the hot and cold shock conditions, the heating state of each component of the catalyst changes suddenly. According to the law of thermal expansion and contraction, the pressure formed by the connector will be reduced, and the seals (such as gaskets being blown away) will be damaged; the internal uneven temperature will cause cracking of parts; the gap between parts will be changed, which may cause abrasions and scratches; the interference state between the pressed parts will be changed, which may cause loosening and displacement, etc.
[0004] According to the statistics of after-sales failure rates in the industry, the main failure mode of the three-way catalytic converter is the cracking of the shell and the damage of the carrier due to the impact of extreme environments. At present, the industry's evaluation of the three-way catalytic converter's resistance to cold and hot shock performance is mainly verified through vehicle road durability tests. Not only is the verification cycle long and the investment huge, but the test is also affected by the environmental weather and cannot be fully simulated and verified. Therefore, how to quickly and accurately analyze whether the three-way catalytic converter can withstand the performance requirements of high and low temperature alternating shocks is a difficult and urgent task. Summary of the invention
[0005] To solve the above problems, this paper provides a test method for evaluating the thermal shock resistance of passenger car three-way catalytic converters. Through a simple test bench, the working conditions of extremely high engine temperature and low ambient temperature are simulated to quickly verify the thermal shock resistance of parts. Compared with traditional methods, the cycle is greatly shortened, the required equipment and site are simple, and the verification cost is greatly saved. In addition, the influence of extreme environment can be simulated, and the verification results are accurate.
[0006] The technical solution of the present invention is described as follows in conjunction with the accompanying drawings:
[0007] A test method for evaluating the thermal shock resistance of a three-way catalytic converter for a passenger car comprises the following steps:
[0008] Step 1: Connect the thermal shock test bench, set the air flow direction and arrange the thermocouples;
[0009] Step 2: preheating the gasket in the three-way catalytic converter 3 before the test;
[0010] Step 3: Set the working conditions and test parameters to conduct thermal shock test on the thermal shock bench;
[0011] Step 4: Failure judgment is made on the carrier, shell and gasket of the three-way catalytic converter 3, so as to evaluate the performance.
[0012] Furthermore, in step one, the thermal shock test bench includes a flexible joint 1, a decoupling device 2, a three-way catalytic converter 3, a vibration table 4, and a universal joint 5; the first thermocouple 6 is connected to the intermediate pipeline between the flexible joint 1 and the three-way catalytic converter 3 through a welding nut; the outlet end pipeline of the three-way catalytic converter 3 is fixed on the vibration table 4 through the universal joint 5; the second thermocouple 7 is connected to the outlet end pipeline of the three-way catalytic converter 3 through a welding nut; the decoupling device 2 and the vibration table 4 are placed on a horizontal surface.
[0013] Furthermore, in step one, the ventilation airflow direction is from the first thermocouple 7 to the second thermocouple 7 .
[0014] Furthermore, in the step 2, when the gasket is an intumescent gasket, the three-way catalytic converter is heated at 650° C. for 1 hour; when the gasket is a non-intumescent gasket, the three-way catalytic converter is heated at 350° C. for 30 minutes.
[0015] Furthermore, in step 3, the operating conditions and test parameters set are as follows:
[0016] For gasoline vehicles with less than 6 cylinders, the intake temperature is set to 730±15℃, the outlet temperature is set to 730±15℃, and the gas flow rate is 123~148kg·h -1 , the acceleration is set to 20±3 / g, the frequency is set to 135±5 / hz; the installation direction of the three-way catalytic converter 3 is horizontal; the number of test cycles is 150 times; the test time is 20h;
[0017] For gasoline vehicles with ≥6 cylinders, the intake temperature is set to 730±15℃, the outlet temperature is set to 730±15℃, and the gas flow rate is 247~300kg·h -1 , the acceleration is set to 20±3 / g, the frequency is set to 135±5 / hz; the installation direction of the three-way catalytic converter 3 is horizontal; the number of test cycles is 150 times; the test time is 20h;
[0018] For diesel vehicles with less than 6 cylinders, the intake temperature is set to 500±15℃, the outlet temperature is set to 500±15℃, and the gas flow rate is 384±38.4kg·h -1 , the acceleration is set to 20±3 / g, the frequency is set to 135±5 / hz; the installation direction of the three-way catalytic converter 3 is horizontal; the number of test cycles is 150 times; the test time is 20h;
[0019] For diesel vehicles with ≥6 cylinders, the intake temperature is set to 500±15℃, the outlet temperature is set to 500±15℃, and the gas flow rate is 768±76.8kg·h -1 , the acceleration is set to 20±3 / g, the frequency is set to 135±5 / hz; the installation direction of the three-way catalytic converter 3 is horizontal; the number of test cycles is 150 times; the test time is 20h.
[0020] Furthermore, in step three, each test cycle consists of 7.5 minutes of heating and 30±2 seconds of water quenching.
[0021] Furthermore, in the step 4, if the displacement of the carrier assembly does not exceed 2 mm, the carrier assembly has no damage or cracks, the shell of the three-way catalytic converter 3 has no deformation, and the gasket has no blow-out, then the thermal shock resistance is judged to be qualified, otherwise it is deemed to be unqualified.
[0022] The beneficial effects of the present invention are:
[0023] The present invention uses a simple test bench to simulate the extremely high temperature of the engine and the low temperature of the environment to quickly verify the resistance of parts to cold and hot shock. Compared with traditional methods, the cycle is greatly shortened, the required equipment and site are simple, and the verification cost is greatly saved. It can also simulate the impact of extreme environments and the verification results are accurate. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.
[0025] Figure 1 It is a schematic diagram of the structure of the thermal shock test bench in the present invention;
[0026] Figure 2 for Figure 1 Sectional view at AA;
[0027] Figure 3 Schematic diagram of the curves of heating time and water quenching time for each test cycle.
[0028] In the figure:
[0029] 1. Flexible joint; 2. Decoupling device; 3. Three-way catalytic converter; 4. Vibration table; 5. Universal joint; 6. First thermocouple; 7. First thermocouple. DETAILED DESCRIPTION
[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0031] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.
[0032] Embodiment 1
[0033] This embodiment provides a test method for evaluating the thermal shock resistance of a three-way catalytic converter for a passenger car, comprising the following steps:
[0034] Step 1: Connect the thermal shock test bench and set the air flow direction, such as Figure 1 and Figure 2 As shown;
[0035] The thermal shock test bench includes a flexible joint 1, a decoupling device 2, a three-way catalytic converter 3, a vibration table 4, and a universal joint 5; a first thermocouple 6 is connected to the intermediate pipeline between the flexible joint 1 and the three-way catalytic converter 3 through a welding nut; the outlet pipeline of the three-way catalytic converter 3 is fixed on the vibration table 4 through a universal joint 5; a second thermocouple 7 is connected to the outlet pipeline of the three-way catalytic converter 3 through a welding nut; the decoupling device 2 and the vibration table 4 are placed on a horizontal surface.
[0036] Step 2: preheating the gasket in the three-way catalytic converter 3 before the test;
[0037] When the gasket is an intumescent gasket, the three-way catalytic converter is heated at 3650°C for 1 hour; when the gasket is a non-intumescent gasket, the three-way catalytic converter is heated at 3350°C for 30 minutes.
[0038] Step 3: Set the working conditions and test parameters to conduct a thermal shock test on a thermal shock bench; the set working conditions and test parameters are shown in Table 1:
[0039] Table 1
[0040]
[0041] Each test cycle consists of 7.5 minutes of heating and (30±2) seconds of water quenching, as shown in the curve. The opening pressure of the three nozzles is (172±1.5) kPa, the water spray volume is (10±0.1) L / min, the water temperature is (10~30)℃, and the nozzle arrangement is as follows Figure 2 shown.
[0042] Step 4: Failure judgment is made on the carrier, shell and gasket of the three-way catalytic converter 3, so as to evaluate the performance.
[0043] When the displacement of the carrier assembly does not exceed 2mm; the carrier assembly has no damage or cracks; the shell of the three-way catalytic converter 3 has no deformation; and the gasket has no blow-out, the resistance to cold and hot shock is judged to be qualified, otherwise it is deemed to be unqualified.
[0044] Embodiment 2
[0045] In this embodiment, a catalyst carrier of a certain brand and a certain model with a new specification is selected to analyze whether the thermal shock resistance of the catalyst assembly is qualified. At that time, the engine had not completed the bench calibration and did not meet the conditions for vehicle verification. In order to quickly analyze and judge, the method provided in this embodiment was used to evaluate the thermal shock resistance of the test parts. The process and results are shown in Table 2:
[0046]
[0047] The consistency rate between the results of the resistance to cold and heat shock performance detected by the method of Example 1 and the results of the resistance to cold and heat shock performance detected by the traditional method is more than 99%. The detection cycle is greatly shortened, the required equipment and site are simple, the verification cost is greatly saved, and the influence of extreme environment can be simulated, and the verification result is accurate.
[0048] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the protection scope of the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention. These simple variations all belong to the protection scope of the present invention.
[0049] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.
[0050] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.
Claims
1. A test method for evaluating the thermal shock resistance of a three-way catalytic converter for a passenger car, characterized in that: The following steps are involved: Step 1: Connect the thermal shock test bench and set the air flow direction; Step 2: preheating the gasket in the three-way catalytic converter (3) before the test; Step 3: Set the working conditions and test parameters to conduct thermal shock test on the thermal shock bench; Step 4: Failure judgment is made on the carrier, shell and gasket of the three-way catalytic converter (3), so as to evaluate the performance.
2. The method for evaluating the thermal shock resistance of a three-way catalytic converter for a passenger vehicle according to claim 1, characterized in that: In the step 1, the first thermocouple (6) is connected to the intermediate pipeline between the flexible joint (1) and the three-way catalytic converter (3) through a welding nut; the outlet pipeline of the three-way catalytic converter (3) is fixed to the vibration table (4) through a universal joint 5; the second thermocouple (7) is connected to the outlet pipeline of the three-way catalytic converter (3) through a welding nut; and the decoupling device (2) and the vibration table 4 are placed on a horizontal surface.
3. The method for evaluating the thermal shock resistance of a three-way catalytic converter for a passenger vehicle according to claim 1, characterized in that: In the step 1, the ventilation airflow direction is from the first thermocouple (7) to the second thermocouple (7).
4. The method for evaluating the thermal shock resistance of a three-way catalytic converter for a passenger vehicle according to claim 1, characterized in that: In the step 2, when the gasket is an intumescent gasket, the three-way catalytic converter (3) is heated at 650° C. for 1 hour; when the gasket is a non-intumescent gasket, the three-way catalytic converter (3) is heated at 350° C. for 30 minutes.
5. The method for evaluating the thermal shock resistance of a three-way catalytic converter for a passenger vehicle according to claim 1, characterized in that: In step 3, the operating conditions and test parameters set are as follows: For gasoline vehicles with less than 6 cylinders, the intake temperature is set to 730±15℃, the outlet temperature is set to 730±15℃, and the gas flow rate is 123~148kg·h -1 , the acceleration is set to 20±3 / g, the frequency is set to 135±5 / hz; the installation direction of the three-way catalytic converter (3) is horizontal; the number of test cycles is 150 times; the test time is 20h; For gasoline vehicles with ≥6 cylinders, the intake temperature is set to 730±15℃, the outlet temperature is set to 730±15℃, and the gas flow rate is 247~300kg·h -1 , the acceleration is set to 20±3 / g, the frequency is set to 135±5 / hz; the installation direction of the three-way catalytic converter (3) is horizontal; the number of test cycles is 150 times; the test time is 20h; For diesel vehicles with less than 6 cylinders, the intake temperature is set to 500±15℃, the outlet temperature is set to 500±15℃, and the gas flow rate is 384±38.4kg·h -1 , the acceleration is set to 20±3 / g, the frequency is set to 135±5 / hz; the installation direction of the three-way catalytic converter (3) is horizontal; the number of test cycles is 150 times; the test time is 20h; For diesel vehicles with ≥6 cylinders, the intake temperature is set to 500±15℃, the outlet temperature is set to 500±15℃, and the gas flow rate is 768±76.8kg·h -1 , the acceleration is set to 20±3 / g, the frequency is set to 135±5 / hz; the installation direction of the three-way catalytic converter (3) is horizontal; the number of test cycles is 150 times; and the test time is 20 hours.
6. The method for evaluating the thermal shock resistance of a three-way catalytic converter for a passenger vehicle according to claim 1, characterized in that: In step 3, each test cycle consists of 7.5 minutes of heating and 30±2 seconds of water quenching.
7. The method for evaluating the thermal shock resistance of a three-way catalytic converter for a passenger vehicle according to claim 1, characterized in that: In the step 4, the displacement of the carrier assembly does not exceed 2 mm; The carrier assembly has no damage or cracks; the three-way catalytic converter (3) shell has no deformation; the liner has no blowout, If the product meets the requirements of the manufacturer, the product is judged to have qualified performance in terms of resistance to cold and hot shocks; otherwise, the product is deemed to have failed the performance test.