Engine exhaust thermal shock test method

Abstract

The invention relates to the technical field of automobile engine manufacturing, and particularly discloses an engine exhaust thermal shock test method, an engine (including exhaust system parts) is carried on an engine pedestal, the engine pedestal is cooperatively provided with an exhaust thermal shock test sensor support, and the output end of the engine is in transmission connection with an adjustable load; the temperature of the engine exhaust system is forcibly heated and cooled in a short time, and the temperature is rapidly changed for multiple times, so that the test condition is harsh, and the bearing capacity of parts of the engine exhaust system on thermal stress generated by rapid change of high and low temperatures and the sealing performance of connecting surfaces among the parts of the exhaust system can be examined; the bearing capacity of the sealing performance between the engine exhaust system parts and the combination surfaces of the engine exhaust system parts on high and low temperature instantaneous changes is investigated.

Description

Technical Field

[0001] The invention relates to the technical field of automobile engine manufacturing, and in particular to an engine exhaust thermal shock test method. Background Art

[0002] The general reliability test method of the automobile engine on the test bench includes hot and cold shock tests, which are used for the design, certification and quality inspection of automobile engines.

[0003] According to GB / T 19055 "Automobile Engine Reliability Test Methods", the hot and cold shock test focuses on the impact of changes in cooling water outlet temperature on engine performance, but does not focus on changes in exhaust system temperature. It cannot examine the reliability of the sealing between engine exhaust system components and their joint surfaces under harsh environments of high and low temperature shocks in a short period of time. Summary of the invention

[0004] The purpose of the present invention is to provide an engine exhaust thermal shock test method, which examines the ability of the engine exhaust system components and their joint surfaces to withstand instantaneous changes in high and low temperatures.

[0005] The present invention is implemented by the following technical solution: An engine exhaust thermal shock test method comprises the following steps:

[0006] S1, engine heat engine;

[0007] S2, engine acceleration, load increase;

[0008] S3. The engine maintains a corresponding stable speed and load when the exhaust temperature is highest;

[0009] S4, engine speed reduction, load reduction;

[0010] S5. The engine maintains a corresponding stable speed and load when the exhaust temperature is lowest;

[0011] S6, steps S2 to S5 are one cycle, and 106 cycles are completed continuously;

[0012] S7, the engine slows down and reduces the load until it stops;

[0013] S8. Perform visual inspection and leakage test on the exhaust system. If leakage is found, stop the test; if no leakage is found, continue the test;

[0014] S9. Steps S1 to S8 constitute one cycle, which is repeated 15 times continuously.

[0015] Furthermore, in step S1, the following steps are specifically included:

[0016] S11. Run the engine at 40% to 80% of the rated speed and keep the load at the minimum for not less than 10 minutes;

[0017] S12. Record the current maximum exhaust temperature and mark it as the first temperature.

[0018] Furthermore, in step S2, the following steps are specifically included:

[0019] S21, accelerate the engine to the rated speed;

[0020] S22, load increased to maximum;

[0021] S23, completing steps S21 to S22 in no more than 10 seconds;

[0022] S24. Record the current maximum exhaust temperature and mark it as the second temperature.

[0023] Furthermore, in step S3, the running time is not less than 200 seconds.

[0024] Furthermore, in step S4, the following steps are specifically included:

[0025] S41, operate the engine at 40% to 80% of the rated speed and keep the load at the minimum;

[0026] S42, lowering the exhaust temperature to a first temperature;

[0027] S43. Complete steps S41 to S42 in no more than 10 seconds.

[0028] Furthermore, the duration of step S5 is not less than 550 seconds.

[0029] Furthermore, it takes no more than 18 seconds to complete step S7.

[0030] Furthermore, after completing step S7, a cooling device is used to perform auxiliary cooling on the engine exhaust system components for not less than 3600 seconds.

[0031] Furthermore, in step S8, the following steps are specifically included:

[0032] S81. Investigate the deformation of components of different materials, structures and shapes after being exposed to extreme environments;

[0033] S82, turn the engine to the top dead center of cylinder 1;

[0034] S83, exhaust system connected to pressure regulator and compressed air;

[0035] S84. Spray the exhaust system with a foaming agent, then visually inspect the exhaust system for bubbles and record them;

[0036] 0 – no bubbles;

[0037] 1- small static bubbles;

[0038] 2-Growing bubbles;

[0039] 3-Continuous leakage cannot form bubbles;

[0040] S85, record the determination result:

[0041] 0, 1 – acceptable;

[0042] 2 – Conditional acceptance;

[0043] 3 – Unacceptable.

[0044] Furthermore, in steps S1-S9, the total engine operating time is not less than 338 hours.

[0045] The technical solution of the present invention has at least the following advantages and beneficial effects:

[0046] The engine exhaust system temperature is forced to heat and cool in a short period of time, and the temperature changes rapidly multiple times. The test conditions are more stringent, which can assess the engine exhaust system components' ability to withstand thermal stress caused by rapid changes in high and low temperatures, as well as the sealing performance of the connection surfaces between the exhaust system components. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] 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.

[0048] Figure 1 A flowchart of an engine exhaust thermal shock test method provided by the present invention; DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0050] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0051] Reference Figure 1 As shown, this embodiment provides an engine (including exhaust system components) exhaust thermal shock test method, the engine (including exhaust system components) is mounted on an engine bench, the engine bench is equipped with an exhaust thermal shock test sensor bracket, and an adjustable load is connected to the engine output end; the test method includes the following steps:

[0052] S1, engine heat engine;

[0053] In step S1, the following steps are specifically included:

[0054] S11. Run the engine at 40% to 80% of rated speed, with the coolant outlet temperature reaching 88±5°C, and with the load kept at a minimum for not less than 10 minutes;

[0055] S12. Record the current temperature change, select the highest exhaust temperature, and mark it as the first temperature.

[0056] S2, engine acceleration, load increase;

[0057] In step S2, the following steps are specifically included:

[0058] S21, increase the fuel supply to make the engine speed reach the rated speed;

[0059] S22. At the same time, the load is increased to the maximum load of the engine, causing the exhaust temperature to rise rapidly;

[0060] S23. It should be noted that it takes no more than 10 seconds to complete steps S21 to S22;

[0061] S24. Then record the current maximum exhaust temperature and mark it as the second temperature.

[0062] S3. The engine shall continue to operate at a stable speed and load when the exhaust temperature is the highest, and the operating time shall not be less than 200 seconds;

[0063] S4, engine speed reduction, load reduction;

[0064] In step S4, the following steps are specifically included:

[0065] S41. Lower the throttle to make the engine run at 40% to 80% of the rated speed and keep the load at the lowest level;

[0066] S42, observing the exhaust temperature, and lowering the exhaust temperature to a first temperature;

[0067] S43. It should be noted that it takes no more than 10 seconds to complete steps S41 to S42.

[0068] S5. The engine maintains a corresponding stable speed and load when the exhaust temperature is lowest; and the duration is not less than 550 seconds.

[0069] S6, steps S2 to S5 are one cycle, and 106 cycles are completed continuously;

[0070] S7, the engine slows down and reduces the load until it stops. It should be noted that it takes no more than 18 seconds to complete step S7.

[0071] After completing step S7, use cooling equipment, such as an air cooler or a water cooler, to assist cooling of the engine exhaust system components for no less than 3600 seconds.

[0072] S8. Perform visual inspection and leakage test on the exhaust system. If leakage is found, stop the test; if no leakage is found, continue the test;

[0073] In step S8, the following steps are specifically included:

[0074] S81. Investigate the deformation of components of different materials, structures and shapes in extreme environments. Take photos or videos to record the deformation.

[0075] S82, then turn the engine to the top dead center of cylinder 1;

[0076] S83, and connecting a pressure regulator and compressed air to the exhaust system of the engine, and then pumping in the compressed air;

[0077] S84. Spray the exhaust system with a foaming agent (such as soapy water), then visually inspect the exhaust system for bubbles and record them;

[0078] 0 – no bubbles;

[0079] 1- small static bubbles;

[0080] 2-Growing bubbles;

[0081] 3-Continuous leakage cannot form bubbles;

[0082] S85, record the determination result:

[0083] 0, 1 – acceptable;

[0084] 2 – Conditional acceptance;

[0085] 3 – Unacceptable.

[0086] S9. Steps S1 to S8 constitute one cycle, which is repeated 15 times continuously.

[0087] More specifically, in steps S1-S9, the total engine operating time is not less than 338 hours to ensure that the actual use of the engine is restored to the greatest extent.

[0088] In summary, the temperature of the engine exhaust system is forced to heat and cool in a short period of time, and the temperature changes rapidly multiple times. The test conditions are more stringent, which can assess the engine exhaust system components' ability to withstand thermal stress caused by rapid changes in high and low temperatures, as well as the sealing performance of the connection surfaces between the exhaust system components.

[0089] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An engine exhaust thermal shock test method, characterized in that: The following steps are involved: S1, engine heat engine; S2, engine acceleration, load increase; S3. The engine maintains a corresponding stable speed and load when the exhaust temperature is highest; S4, engine speed reduction, load reduction; S5. The engine maintains a corresponding stable speed and load when the exhaust temperature is lowest; S6, steps S2 to S5 are one cycle, and 106 cycles are completed continuously; S7, the engine slows down and reduces load until it stops; S8. Perform visual inspection and leakage test on the exhaust system. If leakage is found, stop the test; if no leakage is found, continue the test; S9. Steps S1 to S8 constitute one cycle, which is repeated 15 times continuously.

2. The engine exhaust thermal shock test method according to claim 1, characterized in that: In step S1, the following steps are specifically included: S11. Run the engine at 40% to 80% of the rated speed and keep the load at the minimum for not less than 10 minutes; S12. Record the current maximum exhaust temperature and mark it as the first temperature.

3. The engine exhaust thermal shock test method according to claim 1, characterized in that: In step S2, the following steps are specifically included: S21, accelerate the engine to the rated speed; S22, load increased to maximum; S23, completing steps S21 to S22 in no more than 10 seconds; S24. Record the current maximum exhaust temperature and mark it as the second temperature.

4. The engine exhaust thermal shock test method according to claim 1, characterized in that: In step S3, the running time is not less than 200 seconds.

5. The engine exhaust thermal shock test method according to claim 1, characterized in that: In step S4, the following steps are specifically included: S41, operate the engine at 40% to 80% of the rated speed and keep the load at the minimum; S42, lowering the exhaust temperature to a first temperature; S43. Complete steps S41 to S42 in no more than 10 seconds.

6. The engine exhaust thermal shock test method according to claim 1, characterized in that: The duration of step S5 is not less than 550 seconds.

7. The engine exhaust thermal shock test method according to claim 1, characterized in that: It takes no more than 18 seconds to complete step S7.

8. The engine exhaust thermal shock test method according to claim 7, characterized in that: After completing step S7, use cooling equipment to assist cooling of engine exhaust system components for no less than 3600 seconds.

9. The engine exhaust thermal shock test method according to claim 1, characterized in that: In step S8, the following steps are specifically included: S81. Investigate the deformation of components of different materials, structures and shapes after being exposed to extreme environments; S82, turn the engine to the top dead center of cylinder 1; S83, exhaust system connected to pressure regulator and compressed air; S84. Spray the exhaust system with a foaming agent, then visually inspect the exhaust system for bubbles and record them; 0 – no bubbles; 1- small static bubbles; 2-Growing bubbles; 3-Continuous leakage cannot form bubbles; S85, record the determination result: 0, 1 – acceptable; 2 – Conditional acceptance; 3 – Unacceptable.

10. An engine exhaust thermal shock test method according to any one of claims 1 to 9, characterized in that: In steps S1-S9, the total engine operating time is not less than 338 hours.

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