Air tightness detection device and air tightness detection method

Abstract

The invention relates to an air tightness detection device and method. The air tightness detection device comprises a negative pressure pump, a pipeline assembly, a valve assembly and an air pressure detection piece. The pipeline assembly comprises a first pipeline and a second pipeline. The valve assembly comprises a first valve and a second valve. The first pipeline is arranged between the first valve and the negative pressure pump in a communicating mode to form an air pressure detection branch. The second pipeline is arranged between the first pipeline and the second valve in a communicating mode to form a protection branch. And the protection branch is communicated with the outside through a second valve. The negative pressure pump is used for providing negative pressure for the air pressure detection branch and the protection branch. The end, away from the negative pressure pump, of the air pressure detection branch communicates with an engine cylinder cover. The air pressure detection part is arranged on the air pressure detection branch. The air pressure detection part is used for detecting air pressure of the air pressure detection branch. According to the air tightness detection device and method, the conditions that the negative pressure pump idles and works unstably in negative pressure air tightness detection can be avoided.

Description

Technical Field

[0001] The present application relates to the technical field of cylinder head sealing detection, and in particular to an airtightness detection device and an airtightness detection method. Background Art

[0002] In engines in the automotive and other fields, cylinder heads are provided on the engines to close the intake and exhaust cylinder heads. Generally, the opening and closing of the cylinder heads are achieved through the setting of valves and valve seats. Engines are usually used in high temperature and high pressure environments. Under the influence of high temperature and high pressure, wear and ablation between valves and valve seats are inevitable, combustion waste accumulates, and the elastic force of valve springs weakens after aging, resulting in poor sealing of valves and valve seats. This can easily lead to insufficient intake or accumulation of exhaust gas in the combustion chamber, which is not conducive to the performance of the engine.

[0003] Based on this, in order to ensure the performance of the engine, it is necessary to perform airtightness tests regularly before the engine leaves the factory and during use to confirm the sealing reliability of the cylinder head valve and valve seat.

[0004] In the related technology, the more accurate methods for testing the air tightness of the cylinder head of the engine are mainly as follows: one is the oil leakage detection method, which is to place the valve into the valve seat, pour gasoline on the top surface of the valve, and observe whether there is leakage. If there is no leakage, the sealing is good; if there is leakage, it indicates that the seal is not tight. However, the oil leakage detection method injects specific media, such as gasoline, which is difficult to clean and will easily affect the sealing medium between the valve and the valve seat, affecting the subsequent opening and closing of the valve.

[0005] The second is the positive pressure detection method, which specifically involves inflating the workpiece to be tested, closing the inflation valve after reaching the target value, and monitoring the multi-stage pressure changes from inflation to pressure maintenance over a period of time to determine whether the product being tested is leaking. However, the positive pressure detection method is a qualitative test that cannot be quantitative because it confirms that the pressure does not drop within a certain period of time. At the same time, the positive pressure detection method requires squeezing air and other inflation media into the engine, which can easily cause pollution to the engine's combustion chamber.

[0006] The third is the negative pressure detection method, which specifically involves negative pressure detection of the intake and exhaust cylinder heads, and the judgment of the sealing performance of the cylinder heads is achieved through negative pressure detection. However, the negative pressure pump in the related technology is directly connected to the engine. When the negative pressure pump drains the gas in the engine, it will cause the negative pressure pump to run idle, causing damage to the negative pressure pump and affecting its service life. Summary of the invention

[0007] Based on this, it is necessary to provide an airtightness detection device and method to address the problem of unstable operation of the negative pressure pump in negative pressure airtightness detection.

[0008] An air tightness detection device is used to detect the air tightness of an engine cylinder head. The air tightness detection device comprises: a negative pressure pump, a pipeline component, a valve component and an air pressure detection component.

[0009] A pipeline assembly, comprising a first pipeline and a second pipeline;

[0010] The valve assembly comprises a first valve and a second valve; the first pipeline is arranged between the first valve and the negative pressure pump to form an air pressure detection branch; the second pipeline is arranged between the first pipeline and the second valve to form a protection branch; the protection branch is connected to the outside through the second valve; the negative pressure pump is used to provide negative pressure for the air pressure detection branch and the protection branch; the end of the air pressure detection branch away from the negative pressure pump is used to communicate with the engine cylinder head;

[0011] An air pressure detection component is arranged in the air pressure detection branch; the air pressure detection component is used to detect the air pressure of the air pressure detection branch.

[0012] In one embodiment, the first pipe has a first end and a second end opposite to each other, the first end is connected to the negative pressure pump, the second end is connected to the first valve, and the second pipe is communicated with the first end; the air pressure detection element is arranged between the first end and the second end and is communicated with the first pipe.

[0013] In one embodiment, the air tightness detection device also includes a connecting joint; the connecting joint is provided with a tube cavity, a third end and a fourth end; the tube cavity is arranged through the third end and the fourth end; the third end is inserted and matched with the air pressure detection branch to connect the negative pressure detection branch with the tube cavity; the fourth end is sealed with the periphery of the engine cylinder head to connect the engine cylinder head with the tube cavity.

[0014] In one embodiment, the fourth end to the third end are gradually converged along the depth direction.

[0015] In one embodiment, the pipeline assembly further includes a third pipeline, and the valve assembly further includes a third valve. The third pipeline is connected between the second end and the third valve to form a test branch; the test branch is connected to the outside through the third valve.

[0016] In one embodiment, the valve assembly further includes a fourth valve; the fourth valve is connected to the air pressure detection branch and is connected between the first end and the second end.

[0017] An air tightness detection method based on the air tightness detection device in the above embodiment is used to detect the air tightness of an engine cylinder head, wherein the engine is provided with an intake cylinder head and an exhaust cylinder head; an end of an air pressure detection branch away from the first valve is connected and matched with one of the intake cylinder head and the exhaust cylinder head; the air tightness detection method comprises:

[0018] Turning on the negative pressure pump, closing the first valve, and adjusting the opening of the second valve until the air pressure value of the air pressure detection member reaches the first value, and stopping adjusting the opening of the second valve to keep the second valve at the first opening;

[0019] Opening the first valve;

[0020] After a preset time, the test air pressure data of the air pressure detection component is read; when the test air pressure data is less than or equal to a first value, it is determined that the engine cylinder head is in a normal sealing state; otherwise, it is determined that the engine cylinder head is in a leakage state.

[0021] In one embodiment, the air tightness detection method further includes:

[0022] Acquire an airtight detection mode, wherein the airtight detection mode includes an intake cylinder head airtight detection mode and an exhaust cylinder head airtight detection mode;

[0023] When the air tightness detection mode is in the intake cylinder head air tightness detection mode, the end of the air pressure detection branch away from the negative pressure pump is connected to the air inlet; when the air tightness detection mode is in the exhaust cylinder head air tightness detection mode, the end of the air pressure detection branch away from the negative pressure pump is connected to the exhaust cylinder head.

[0024] In one embodiment, the air tightness detection method further includes:

[0025] When the air tightness detection mode is in the exhaust cylinder head air tightness detection mode, the end of the air pressure detection branch away from the negative pressure pump is connected to the combustion chamber of the engine, so that the air pressure detection branch is connected to the exhaust cylinder head through the combustion chamber, and the air inlet is sealed;

[0026] And / or, when the air-tight detection mode is in the intake cylinder head air-tight detection mode, the end of the air pressure detection branch away from the negative pressure pump is sealed and connected to the periphery of the intake cylinder head, so that the end of the air pressure detection branch away from the negative pressure pump is connected and cooperated with the intake cylinder head.

[0027] An air tightness detection method based on the air tightness detection device in the above embodiment is used to detect the air tightness of an engine cylinder head, wherein the engine is provided with an intake cylinder head and an exhaust cylinder head; an end of an air pressure detection branch away from the first valve is connected and matched with one of the intake cylinder head and the exhaust cylinder head; the air tightness detection method comprises:

[0028] Turning on the negative pressure pump, closing the first valve and the third valve, and adjusting the opening of the second valve until the air pressure value of the air pressure detection member reaches the first value, and stopping adjusting the opening of the second valve to keep the second valve at the first opening;

[0029] Opening the third valve and keeping the third valve at a second opening according to a preset air pressure value, and obtaining first air pressure data from the air pressure detection meter;

[0030] When the first air pressure data is less than or equal to the preset air pressure value, the first valve is opened, and after a preset time, the test air pressure data of the air pressure detection component is read; when the test air pressure data is less than or equal to the first value, it is determined that the engine cylinder head is in a normal sealing state; otherwise, it is determined that the engine cylinder head is in a leaking state;

[0031] When the first air pressure data is greater than the preset air pressure value, the air tightness detection is ended.

[0032] An air tightness detection method based on the above embodiment is used to detect the air tightness of an engine cylinder head, and the air tightness detection method further includes:

[0033] Turning on the negative pressure pump, closing the first valve, the third valve and the fourth valve, and adjusting the opening of the second valve until the air pressure value of the air pressure detection member reaches the first value, and stopping adjusting the opening of the second valve to keep the second valve at the first opening;

[0034] Opening the third valve and the fourth valve, and adjusting the opening of the third valve until the air pressure value of the air pressure detection member reaches a preset air pressure value, and stopping adjusting the opening of the third valve to keep the third valve at the second opening;

[0035] The fourth valve is closed to obtain the second air pressure data of the air pressure detection element; the fourth valve is opened to obtain the third air pressure data of the air pressure detection element;

[0036] When the second air pressure data is less than or equal to the first value, and the third air pressure data is less than or equal to the preset air pressure value, the first valve is opened, and after a preset time, the test air pressure data of the air pressure detection component is read;

[0037] When the second air pressure data is greater than the first value, or the third air pressure data is greater than the preset air pressure value, the air tightness detection is terminated.

[0038] In one embodiment, the closing of the fourth valve to obtain the second air pressure data of the air pressure detection element; and the opening of the fourth valve to obtain the third air pressure data of the air pressure detection element further include:

[0039] Acquire a first acquisition number of the second air pressure data, and acquire a second acquisition number of the third air pressure data; assuming that the first acquisition number is N1 and the second acquisition number is N2;

[0040] When N1=N2≥2, the first valve is opened, and after a preset time, the test air pressure data of the air pressure detection component is read; otherwise, the fourth valve is closed to obtain the second air pressure data of the air pressure detection component; the fourth valve is opened to obtain the third air pressure data of the air pressure detection component.

[0041] The air tightness detection device and the air tightness detection method are connected to the air pressure detection branch through the protection branch, so that when the air pressure detection branch is connected, even if the negative pressure pump dries up the air in the air pressure detection branch, the air pressure detection branch and the engine are both in a negative pressure state, and no other medium needs to be introduced, thereby ensuring the performance of the engine. Furthermore, the opening of the protection branch can ensure that the negative pressure pump can cooperate with the external suction, avoid the negative pressure pump from idling for a long time and short circuiting, and improve the working stability of the negative pressure pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagram of the structure of an airtightness detection device in one embodiment.

[0043] Figure 2 FIG. 4 is a schematic diagram of the operation of the air pressure detection branch in one embodiment.

[0044] Figure 3 Schematic diagram of the coordination between the protection branch and the air pressure detection branch in one embodiment.

[0045] Figure 4 Schematic diagram of the process of an airtightness detection method in one embodiment.

[0046] Figure 5 for Figure 4 A schematic diagram of a specific flow chart of step S1 of an embodiment of the present invention.

[0047] Figure 6 FIG. 1 is a schematic diagram of the operation of the airtightness detection device when executing step S1 in an embodiment.

[0048] Figure 7FIG. 1 is a flow chart of steps S1 and S2 in one embodiment.

[0049] Figure 8 Schematic diagram of the execution method of different airtightness detection modes in one embodiment.

[0050] Fig. 9 FIG. 4 is a flowchart of an execution method of different airtightness detection modes in another embodiment.

[0051] Description of reference numerals:

[0052] 100. Air tightness detection device; 110. Negative pressure pump; 120. Pipe assembly; 121. First pipeline; 1211. First end; 1212. Second end; 122. Second pipeline; 123. Third pipeline; 130. Valve assembly; 131. First valve; 132. Second valve; 133. Third valve; 134. Fourth valve; 140. Air pressure detection component; 150. Air pressure detection branch; 160. Protection branch; 170. Test branch; 180. Connector; 181. Third end; 182. Fourth end. DETAILED DESCRIPTION

[0053] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0054] See also Figure 1 , Figure 1 A structural schematic diagram of an air tightness detection device 100 in an embodiment of the present application is shown. The air tightness detection device 100 provided in an embodiment of the present application includes a negative pressure pump 110, a pipeline assembly 120, a valve assembly 130 and an air pressure detection component 140.

[0055] like Figure 2 and Figure 3As shown, specifically, the pipeline assembly 120 includes a first pipeline 121 and a second pipeline 122. The valve assembly 130 includes a first valve 131 and a second valve 132. The first pipeline 121 is connected and arranged between the first valve 131 and the negative pressure pump 110 to form an air pressure detection branch 150. The second pipeline 122 is connected and arranged between the first pipeline 121 and the second valve 132 to form a protection branch 160. The protection branch 160 is connected to the outside through the second valve 132. The negative pressure pump 110 is used to provide negative pressure for the air pressure detection branch 150 and the protection branch 160. One end of the air pressure detection branch 150 away from the negative pressure pump 110 is used to communicate with the engine cylinder head.

[0056] Among them, the end of the air pressure detection branch 150 away from the negative pressure pump 110 needs to be sealed with the periphery of the engine cylinder head to ensure that there is no leakage at the connection position between the air pressure detection branch 150 and the engine cylinder head. In addition, the engine cylinder head includes an intake cylinder head and an exhaust cylinder head. The end of the air pressure detection branch 150 away from the first valve 131 is connected and matched with one of the intake cylinder head and the exhaust cylinder head. The intake cylinder head refers to the cylinder head corresponding to the intake port in the engine. The exhaust cylinder head refers to the cylinder head corresponding to the exhaust port in the engine.

[0057] The air pressure detection element 140 is disposed in the air pressure detection branch 150 . The air pressure detection element 140 is used to detect the air pressure of the air pressure detection branch 150 .

[0058] Among them, Figure 4 As shown, the airtightness detection device 100 in the above embodiment can implement the following airtightness detection method. The airtightness detection method includes:

[0059] S1. Turn on the negative pressure pump 110, close the first valve 131, and adjust the second valve 132 until the air pressure detection element 140 reaches a first value, and stop adjusting the opening of the second valve 132 to keep the second valve 132 at the first opening.

[0060] That is, the negative pressure pump 110 is used to drain the gas in the pipeline assembly 120 and the engine, so that the pipeline assembly 120 and the engine reach a negative pressure state. The first valve 131 can be opened and adjusted so that the pipeline assembly 120 can maintain negative pressure while maintaining communication with the outside atmosphere, so that even if the negative pressure pump 110 drains the gas in the engine and the pipeline assembly 120, it can still continue to suck gas from the outside atmosphere, thereby avoiding idling of the negative pressure pump 110.

[0061] S2. Open the first valve 131.

[0062] It can be understood that the structure of the engine is as follows: the intake cylinder head corresponding to the intake cylinder head is connected to the combustion chamber through a pipe, and the exhaust cylinder head corresponding to the exhaust cylinder head is connected to the combustion chamber through a pipe. When the engine is turned off, the intake cylinder head corresponding to the intake cylinder head will not be connected to the exhaust side of the combustion chamber, that is, the cylinder head corresponding to the intake cylinder head will not be connected to the cylinder head corresponding to the exhaust cylinder head. Correspondingly, the cylinder head corresponding to the exhaust cylinder head will not be connected to the outlet side of the combustion chamber, that is, the cylinder head corresponding to the exhaust cylinder head will not be connected to the cylinder head corresponding to the exhaust cylinder head.

[0063] Based on this, when one of the cylinder head of the exhaust cylinder head and the cylinder head of the exhaust cylinder head is directly connected to the air pressure detection branch 150, there is no need to seal the other one, and accurate air tightness detection of the one-way cylinder head can be achieved. After opening the first valve 131, the air pressure detection branch 150 can be circulated, the gas of the engine can be drained, and the air tightness of the cylinder head can be detected.

[0064] S3. After a preset time has passed, the test air pressure data of the air pressure detection component 140 is read.

[0065] S4. Determine whether the test air pressure data is greater than or equal to a first value.

[0066] When the test air pressure data is less than or equal to the first value, it is determined that the engine cylinder head is in a normal sealing state. When the test air pressure data is greater than the first value, it is determined that the engine cylinder head is in a leaking state.

[0067] Among them, the preset time may refer to the time for the negative pressure pump 110 to extract the gas in the engine air cavity, or it may refer to the time for the air pressure data to be tested to gradually rise from the first value and then tend to stabilize. The preset time may be related to the gas reserves in the air cavity in the engine. The more gas reserves, the longer the time required to suck and form negative pressure. Based on this, different preset times can be designed according to different engine types, and the negative pressure pressure given by the negative pressure pump 110 can also be designed according to the minimum pressure range that different engine types can withstand. The negative pressure coefficient of the negative pressure pump 110 cannot be lower than the minimum pressure range of the engine.

[0068] For ease of understanding, the detection principle of the air pressure detection branch 150 is explained below.

[0069] After the negative pressure pump 110 drains the gas in the engine, the air pressure detection component 140 can obtain a stable value as the test air pressure data. Since the second valve 132 is in the first opening state, if the air tightness of the cylinder head is good at this time, the air pressure detection branch 150 is connected to the outside world at only one point, that is, the second valve 132, and the test air pressure data is less than or equal to the first value. If there is a leak in the engine cylinder head, the connection between the air pressure detection branch 150 and the cylinder head adds a point connected to the outside world, and the test air pressure data will be greater than the first value.

[0070] In this way, the protection branch 160 is connected to the air pressure detection branch 150, so that when the air pressure detection branch 150 is connected, even if the negative pressure pump 110 drains the air in the air pressure detection branch 150, the air pressure detection branch 150 and the engine are both in a negative pressure state, and no other medium needs to be introduced, thereby ensuring the performance of the engine. Furthermore, the opening of the protection branch 160 can ensure that the negative pressure pump 110 can cooperate with the external suction, avoid the negative pressure pump 110 from idling for a long time and short circuiting, and improve the working stability of the negative pressure pump 110.

[0071] It should be noted that the air pressure detection component 140 can be, but is not limited to, a barometer, and can also be an air pressure sensor or a communicating vessel with a scale, etc., and no excessive restrictions are imposed here.

[0072] In some embodiments, Figure 2 , the pipeline assembly 120 also includes a third pipeline 123. The valve assembly 130 also includes a third valve 133. The first pipeline 121 has a first end 1211 and a second end 1212 opposite to each other. It can be understood that the first end 1211 and the second end 1212 are two ends of the first pipeline 121, and the first end 1211 and the second end 1212 are arranged at intervals. The first end 1211 is connected to the negative pressure pump 110, and the second end 1212 is connected to the first valve 131. The second pipeline 122 is communicated with the first end 1211, and the third pipeline 123 is communicated and arranged between the second end 1212 and the third valve 133 to form a test branch 170. The test branch 170 is connected to the outside through the third valve 133.

[0073] That is, the test branch 170 and the protection branch 160 are connected in parallel to the air pressure detection branch 150. The connection between the test branch 170 and the air pressure detection branch 150 can be controlled by the third valve 133. In addition, the third valve 133 can be restrictive adjustment (only on-off control can be performed) or stepless adjustment, which is not limited here.

[0074] Specifically, in one embodiment, combined with Figure 3 and Figure 5 As shown, in combination with the third valve 133, the air tightness detection method may include:

[0075] S11, turn on the negative pressure pump 110, close the first valve 131 and the third valve 133, and adjust the opening of the second valve 132 until the air pressure value of the air pressure detection component 140 reaches a first value, and stop adjusting the opening of the second valve 132 to keep the second valve 132 at the first opening.

[0076] S12, opening the third valve 133, and keeping the third valve 133 at a second opening according to a preset air pressure value, and obtaining first air pressure data from the air pressure detection meter.

[0077] S13: Determine whether the first air pressure data is less than or equal to a preset air pressure value.

[0078] When the first air pressure data is less than or equal to the preset air pressure value, the process proceeds to step S2 in the above embodiment. Otherwise, the air tightness test ends. The preset air pressure value is related to the second opening degree.

[0079] It is understandable that when the second valve 132 is closed, only the first valve 131 and the third valve 133 are in the open state, and the air tightness detection of the air pressure detection branch 150 can be realized at this time. Among them, the acquisition of the preset opening and the preset air pressure value can be obtained through the following embodiments. In one example, a determined air pressure detection branch 150 with good air tightness is selected and set in the air tightness detection device, and the negative pressure pump 110 provides a constant negative pressure. When the second valve 132 is at a first value, the third valve 133 is opened to a preset opening. According to the air pressure detection component 140, when the third valve 133 is opened to the preset opening, the air pressure value of the air pressure detection branch 150 with good air tightness at this time is used as the preset air pressure value, and the preset opening is used as the second opening.

[0080] Furthermore, the preset opening and preset air pressure value of the third valve 133 obtained in the above embodiment are applied to the air tightness test of the air pressure detection branch 150. When the air pressure detection branch 150 to be detected is tested, if the negative pressure pump 110 provides the same constant negative pressure, the second valve 132 is at the second value and remains at the first opening; the third valve 133 is also opened to the preset opening. If the first air pressure data of the air pressure detection component 140 is less than or equal to the preset air pressure value at this time, it means that the air pressure detection branch 150 has good air tightness and can be put into the air tightness test of the engine cylinder head, and then enter step S2 in the above embodiment. However, when the first air pressure data is greater than the preset air pressure value, it means that a gas leak has occurred at the air pressure detection branch 150, which will affect the accuracy of the air tightness test of the engine cylinder head. Therefore, the air tightness test needs to be stopped and the equipment can be replaced separately.

[0081] In another example, combining Figure 6 and Figure 7As shown, the valve assembly 130 further includes a fourth valve 134. The fourth valve 134 is disposed in communication with the air pressure detection branch 150, and is disposed in communication between the first end 1211 and the second end 1212.

[0082] Specifically, the airtightness detection method further includes:

[0083] S14, turn on the negative pressure pump 110, close the first valve 131, the third valve 133 and the fourth valve 134, and adjust the second valve 132 until the air pressure value of the air pressure detection component 140 reaches the first value, stop adjusting the opening of the second valve 132 to keep the second valve 132 at the first opening.

[0084] S15, opening the third valve 133 and the fourth valve 134 until the air pressure value of the air pressure detection element 140 reaches the preset air pressure value, and stopping adjusting the opening of the third valve 133 to keep the third valve 133 at the second opening.

[0085] That is, when the third valve 133 is opened to the second opening, the air tightness detection device 100 has two controllable leakage sites, namely the second valve 132 and the third valve 133. Based on this, the second value will be smaller than the first value. At the same time, the second value can be used as the air pressure calibration value of the protection branch 160 and the air pressure detection branch 150 in the initial state.

[0086] S16, close the fourth valve 134, and obtain the second air pressure data of the air pressure detection element 140. Open the fourth valve 134, and obtain the third air pressure data of the air pressure detection element 140.

[0087] S17, determining whether the second air pressure data is less than or equal to the first value, and determining whether the third air pressure data is less than or equal to a preset air pressure value.

[0088] When the third air pressure data is less than or equal to the first value, and the fourth air pressure data is less than or equal to the preset air pressure value, the process proceeds to step S2 in the above embodiment. Otherwise, the air tightness test ends.

[0089] It can be understood that the second valve 132 maintains the first opening and the third valve 133 maintains the second opening. If the air tightness of the air pressure detection branch 150 is good, even if the fourth valve 134 is opened or closed, since there is no leakage in the air pressure detection branch 150, the second pressure data and the third pressure data will not change much. At this time, the second air pressure data is less than or equal to the first value, and the third pressure data is less than or equal to the second value.

[0090] On the contrary, if a leak occurs in the air pressure detection branch 150, when the fourth valve 134 is opened or closed, due to the continuous entry of external gas into the air pressure detection branch 150, when the second valve 132 is maintained at the first opening degree and the third valve 133 is maintained at the second opening degree, the second pressure data and the third pressure data will gradually increase, and the second pressure data will be greater than the first value, and the third pressure data will be greater than the second value.

[0091] Based on this, through the steps of the above embodiment, when the fourth valve 134 is opened and closed, the air tightness of the air tightness detection device can be reflected by the changes in the second air pressure data and the third air pressure data, and the self-inspection process of the air tightness detection device can be realized, so as to avoid the poor air tightness of the air tightness of the engine cylinder head from affecting the air tightness detection, thereby improving the air tightness detection accuracy of the engine cylinder head. In addition, the air tightness detection of the air pressure detection device 10 can be realized without the need to test in advance to obtain the preset opening corresponding to the preset air pressure value, which is conducive to simplifying the detection process and improving the detection efficiency.

[0092] Further, in some embodiments, Figure 7 , the air tightness detection method also includes:

[0093] S21, acquiring a first acquisition quantity of second air pressure data, and acquiring a second acquisition quantity of third air pressure data.

[0094] Wherein, each acquisition of the third air pressure data is recorded as 1, and the number of the acquired third air pressure data is the first acquisition number; correspondingly, each acquisition of the fourth air pressure data is recorded as one, and the number of the acquired fourth air pressure data is the second acquisition number. Assume that the first acquisition number is N1 and the second acquisition number is N2.

[0095] S22. Determine whether N1=N2≥2 holds.

[0096] If yes, then go to step S23. Otherwise, go back to step S16.

[0097] S23, opening the first valve.

[0098] S24. After a preset time has passed, the test air pressure data of the air pressure detection component is read.

[0099] S25, judging whether the test air pressure data is less than or equal to the first value. When the test air pressure data is less than or equal to the first value, it is judged that the engine cylinder head is in a normal sealing state. Otherwise, it is judged that the engine cylinder head is in a leaking state.

[0100] In this way, the fourth valve 134 is repeatedly opened and closed, and by comparing the second air pressure data with the first value, and by comparing the third air pressure data with the second value, at least two inspections and verifications of the air tightness of the air tightness detection device are achieved, which is beneficial to improving the air tightness verification accuracy of the air tightness detection device 100, thereby avoiding air tightness detection errors on the engine cylinder head and improving the air tightness detection accuracy of the engine cylinder head.

[0101] It should be noted that the airtightness detection method in the above embodiment can be applied to unidirectional engine cylinder head detection, and can also realize bidirectional detection of the engine cylinder head. Furthermore, the detection method for the intake cylinder head can be consistent with or inconsistent with the detection method for the exhaust cylinder head, and no excessive limitation is made here.

[0102] In a specific embodiment, Figure 8 As shown, step S2 also includes:

[0103] Acquire the airtight detection mode. The airtight detection mode may be acquired by, but is not limited to, manual judgment or intelligent acquisition, etc., and no excessive restrictions are imposed here.

[0104] The air tightness detection mode includes an intake cylinder head air tightness detection mode and an exhaust cylinder head air tightness detection mode.

[0105] When the airtight detection mode is in the intake cylinder head airtight detection mode, the end of the negative pressure detection branch away from the negative pressure pump 110 is connected to the air inlet. When the airtight detection mode is in the exhaust cylinder head airtight detection mode, the end of the negative pressure detection branch away from the negative pressure pump 110 is connected to the exhaust cylinder head.

[0106] That is, in different air tightness detection modes, the air pressure detection branch 150 corresponds to different air inlets and exhaust cylinder heads, so as to realize air tightness detection of the intake cylinder head or the exhaust cylinder head of the engine cylinder head.

[0107] In one embodiment, if Fig. 9 As shown, the airtightness detection method includes:

[0108] When the air tightness detection mode is in the intake cylinder head air tightness detection mode, the end of the air pressure detection branch 150 away from the negative pressure pump 110 is sealed with the peripheral edge of the intake cylinder head, so that the end of the air pressure detection branch 150 away from the negative pressure pump 110 is connected and matched with the intake cylinder head.

[0109] It can be understood that the cylinder head corresponding to the intake cylinder head of the engine is located on the upper surface or side of the engine, and the installation and coordination of the air pressure detection branch 150 therewith is relatively simple. Therefore, the air pressure detection branch 150 can be directly connected and coordinated with the cylinder head corresponding to the intake cylinder head to realize the air tightness detection of the intake cylinder head corresponding to the engine cylinder head, which is simple to operate.

[0110] In another embodiment, if Fig. 9 As shown, the airtightness detection method includes:

[0111] When the air tightness detection mode is in the exhaust cylinder head air tightness detection mode, the end of the air pressure detection branch 150 away from the negative pressure pump 110 is connected to the combustion chamber of the engine, so that the air pressure detection branch 150 is connected and matched with the exhaust cylinder head through the combustion chamber, and the intake cylinder head is sealed.

[0112] It is understandable that the position of the cylinder head corresponding to the exhaust cylinder head of the engine is surrounded by many gas engine parts, so the installation space near the exhaust cylinder head is small, while the installation position of the combustion chamber is relatively sufficient. Based on this, the air pressure detection branch 150 can be connected to the combustion chamber, but because the combustion chamber can be connected to the air inlet, in order to ensure the accuracy of the air tightness detection, the intake cylinder head needs to be sealed to improve the accuracy of the air tightness detection of the exhaust cylinder head.

[0113] In this way, when the air tightness detection mode is in the exhaust cylinder head air tightness detection mode, the connection with the engine combustion chamber is conducive to improving the installation efficiency of the air pressure detection branch 150, and avoiding other parts of the engine from compressing the pipeline, thereby avoiding affecting the detection results of the gas detection branch, and then ensuring the detection accuracy of the air pressure detection branch 150 in detecting the engine cylinder head.

[0114] In other embodiments, the airtight detection device can cooperate with multiple engine cylinder head detections. Specifically, in one example, the airtight detection device also includes a control element and a telescopic component. The telescopic component is telescopically matched with one end of the air pressure detection branch 150 that is away from the negative pressure pump 110, so that the air pressure detection branch 150 can be telescopically matched with the periphery of the engine cylinder head. The control element is communicatively connected with the telescopic component so that the control element controls the telescopic component to move telescopically along the engine cylinder head, and the control element can control the air pressure detection branch 150 to move horizontally in a set direction, so that the telescopic component can be driven to move horizontally in the set direction.

[0115] A plurality of engine cylinder heads are arranged in sequence along a set direction, so that the plurality of engine cylinder heads are arranged in a cycle of intake cylinder head--exhaust cylinder head--intake cylinder head--exhaust cylinder head... The control element is configured to automatically switch the air tightness detection mode. Specifically, it is possible to gradually cycle from the intake cylinder head air tightness detection mode to the exhaust cylinder head air tightness detection mode, and the cycle from the intake cylinder head air tightness detection mode to the exhaust cylinder head air tightness detection mode is a cycle, and the number of cycles is related to the number of engines. In this way, this intelligent mode switching method reduces the process of manual sealing installation, and there is no need for manual hand-held air tightness detection device 100 to replace different engine cylinder heads for air tightness detection, thereby improving the convenience of air tightness detection.

[0116] It should be noted that in the above embodiment, when the airtight detection mode is in the exhaust cylinder head airtight detection mode, the sealing treatment of the air inlet can be achieved by using sealant or vacuum cover, etc., and no excessive restrictions are made here. The sealant can be a rubber adhesive layer, etc. In addition, the control element can be, but is not limited to, a CPU, a remote control component such as an electronic device equipped with Bluetooth, a wireless module, etc.

[0117] In other embodiments, in order to improve the sealing effect of the air pressure detection branch 150 on the engine cylinder head, the air pressure detection branch 150 and the engine cylinder head can be sealed and fixed by a sealing adhesive when the air pressure detection branch 150 and the engine cylinder head are sealed. The sealing adhesive can be a rubber layer, a plastic film layer, etc., which is not limited here.

[0118] In combination with any of the above-mentioned embodiments of the air pressure detection branch 150, Figure 2 The air tightness detection device 100 further includes a connection joint 180. The connection joint 180 is provided with a tube cavity, a third end 181 and a fourth end 182. The tube cavity is arranged through the third end 181 and the fourth end 182. The third end 181 is inserted and matched with the air pressure detection branch 150 so that the negative pressure detection branch is connected to the tube cavity. The fourth end 182 is sealed and connected to the periphery of the engine cylinder head so that the engine cylinder head is connected to the tube cavity.

[0119] In this way, the setting of the connecting joint 180 can improve the sealing performance between the air pressure detection branch 150 and the engine cylinder head, avoid leakage at the connection between the air pressure detection branch 150 and the engine cylinder head, and thus ensure the air tightness detection accuracy of the engine cylinder head.

[0120] Further, in a specific embodiment, see Figures 2 to 3, the fourth end 182 to the third end 181 are gradually gathered in the depth direction. That is, the connection joint 180 is arranged in a cone. The setting of the cone makes the connection joint 180 of the third end 181 have a smaller aperture, so as to better seal with the air pressure detection branch 150, while the connection joint 180 of the fourth end 182 has a larger aperture, so that the periphery of the fourth end 182 can cover the cylinder head of the engine, thereby improving the sealing performance between the fourth end 182 and the cylinder head of the engine.

[0121] It should be noted that the connection joint 180 can be a flexible sealing plug, or a soft suction cup, etc., and no excessive restrictions are imposed here.

[0122] In some embodiments, the connection joint 180 includes a joint body and a soft ring. The joint body is provided with a third end 181 and a fourth end 182 in the above embodiment. The soft ring is surrounded by the periphery of the fourth end 182, and the joint body is such that when the negative pressure pump 110 is pumping, the inner cavity of the soft ring is also in a negative pressure state, and the atmospheric pressure will press the periphery of the soft ring, so that the soft ring is sealed with the engine cylinder head, thereby making the engine cylinder head and the connection joint 180 sealed and connected.

[0123] In this way, through the cooperation of the soft ring and the pressure difference between the negative pressure pump 110 and the atmospheric pressure, the sealing effect between the soft ring and the engine cylinder head can be improved, and when the soft ring is sealed with the engine cylinder head, it will not cause damage or wear to the surface of the engine cylinder head, thereby avoiding the change of the fitting clearance between the engine valve and the valve seat due to damage or wear, and then avoiding the impact on the air tightness of the engine cylinder head during loading and unloading, thereby ensuring the air tightness detection accuracy of the engine cylinder head.

[0124] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0125] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0126] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0127] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0128] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0129] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0130] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. An airtightness detection device for detecting the airtightness of an engine cylinder head, characterized in that: The airtightness detection device comprises: Negative pressure pump; A pipeline assembly, comprising a first pipeline and a second pipeline; The valve assembly comprises a first valve and a second valve; the first pipeline is arranged between the first valve and the negative pressure pump to form an air pressure detection branch; the second pipeline is arranged between the first pipeline and the second valve to form a protection branch; the protection branch is connected to the outside through the second valve; the negative pressure pump is used to provide negative pressure for the air pressure detection branch and the protection branch; the end of the air pressure detection branch away from the negative pressure pump is used to communicate with the engine cylinder head; An air pressure detection component is arranged in the air pressure detection branch; the air pressure detection component is used to detect the air pressure of the air pressure detection branch.

2. The airtightness detection device according to claim 1, characterized in that: The first pipeline has a first end and a second end opposite to each other, the first end is connected to the negative pressure pump, the second end is connected to the first valve, and the second pipeline is communicated with the first end; the air pressure detection component is arranged between the first end and the second end and is communicated with the first pipeline.

3. The airtightness detection device according to claim 1, characterized in that: The air tightness detection device also includes a connecting joint; the connecting joint is provided with a tube cavity, a third end and a fourth end; the tube cavity is arranged through the third end and the fourth end; the third end is inserted and matched with the air pressure detection branch to connect the negative pressure detection branch with the tube cavity; the fourth end is sealed with the periphery of the engine cylinder head to connect the engine cylinder head with the tube cavity.

4. The airtightness detection device according to claim 3, characterized in that: The fourth end and the third end are gradually converged along the depth direction.

5. The airtightness detection device according to any one of claims 2 to 4, characterized in that: The pipeline assembly further includes a third pipeline, and the valve assembly further includes a third valve. The third pipeline is connected between the second end and the third valve to form a test branch. The test branch is connected to the outside through the third valve.

6. The airtightness detection device according to claim 5, characterized in that: The valve assembly further includes a fourth valve; the fourth valve is connected to the air pressure detection branch and is connected between the first end and the second end.

7. An airtightness detection method based on the airtightness detection device according to any one of claims 1 to 4, used for detecting the airtightness of an engine cylinder head, characterized in that: The engine is provided with an intake cylinder head and an exhaust cylinder head; An end of the air pressure detection branch away from the first valve is connected and matched with one of the intake cylinder cover and the exhaust cylinder cover; the air tightness detection method includes: Turning on the negative pressure pump, closing the first valve, and adjusting the opening of the second valve until the air pressure value of the air pressure detection member reaches the first value, and stopping adjusting the opening of the second valve to keep the second valve at the first opening; Opening the first valve; After a preset time, the test air pressure data of the air pressure detection component is read; when the test air pressure data is less than or equal to a first value, it is determined that the engine cylinder head is in a normal sealing state; otherwise, it is determined that the engine cylinder head is in a leakage state.

8. The airtightness detection method according to claim 7, characterized in that: The airtightness detection method further comprises: Acquire an airtight detection mode, wherein the airtight detection mode includes an intake cylinder head airtight detection mode and an exhaust cylinder head airtight detection mode; When the air-tight detection mode is in the intake cylinder head air-tight detection mode, the end of the air pressure detection branch away from the negative pressure pump is connected to the air inlet; when the air-tight detection mode is in the exhaust cylinder head air-tight detection mode, the end of the air pressure detection branch away from the negative pressure pump is connected to the exhaust cylinder head.

9. The airtightness detection method according to claim 8, characterized in that: The airtightness detection method further comprises: When the air tightness detection mode is in the exhaust cylinder head air tightness detection mode, the end of the air pressure detection branch away from the negative pressure pump is connected to the combustion chamber of the engine, so that the air pressure detection branch is connected to the exhaust cylinder head through the combustion chamber, and the air inlet is sealed; And / or, when the air-tight detection mode is in the intake cylinder head air-tight detection mode, the end of the air pressure detection branch away from the negative pressure pump is sealed and connected to the periphery of the intake cylinder head, so that the end of the air pressure detection branch away from the negative pressure pump is connected and cooperated with the intake cylinder head.

10. An airtightness detection method based on the airtightness detection device according to claim 5, used for detecting the airtightness of an engine cylinder head, characterized in that: The engine is provided with an intake cylinder head and an exhaust cylinder head; An end of the air pressure detection branch away from the first valve is connected and matched with one of the intake cylinder cover and the exhaust cylinder cover; the air tightness detection method includes: Turning on the negative pressure pump, closing the first valve and the third valve, and adjusting the opening of the second valve until the air pressure value of the air pressure detection member reaches the first value, and stopping adjusting the opening of the second valve to keep the second valve at the first opening; Opening the third valve and keeping the third valve at a second opening according to a preset air pressure value, and obtaining first air pressure data from the air pressure detection meter; When the first air pressure data is less than or equal to the preset air pressure value, the first valve is opened, and after a preset time, the test air pressure data of the air pressure detection component is read; when the test air pressure data is less than or equal to the first value, it is determined that the engine cylinder head is in a normal sealing state; otherwise, it is determined that the engine cylinder head is in a leaking state; When the first air pressure data is greater than the preset air pressure value, the air tightness detection is ended.

11. An airtightness detection method based on the airtightness detection device according to claim 6, used for detecting the airtightness of an engine cylinder head, characterized in that: The airtightness detection method further comprises: Turning on the negative pressure pump, closing the first valve, the third valve and the fourth valve, and adjusting the opening of the second valve until the air pressure value of the air pressure detection member reaches the first value, and stopping adjusting the opening of the second valve to keep the second valve at the first opening; Opening the third valve and the fourth valve, and adjusting the opening of the third valve until the air pressure value of the air pressure detection member reaches a preset air pressure value, and stopping adjusting the opening of the third valve to keep the third valve at the second opening; The fourth valve is closed to obtain the second air pressure data of the air pressure detection element; the fourth valve is opened to obtain the third air pressure data of the air pressure detection element; When the second air pressure data is less than or equal to the first value, and the third air pressure data is less than or equal to the preset air pressure value, the first valve is opened, and after a preset time, the test air pressure data of the air pressure detection component is read; When the second air pressure data is greater than the first value, or the third air pressure data is greater than the preset air pressure value, the air tightness detection is terminated.

12. The airtightness detection method according to claim 11, characterized in that: The fourth valve is closed to obtain second air pressure data of the air pressure detection component; Opening the fourth valve to obtain the third air pressure data of the air pressure detection element also includes: Acquire a first acquisition number of the second air pressure data, and acquire a second acquisition number of the third air pressure data; assuming that the first acquisition number is N1 and the second acquisition number is N2; When N1=N2≥2, the first valve is opened, and after a preset time, the test air pressure data of the air pressure detection component is read; otherwise, the fourth valve is closed to obtain the second air pressure data of the air pressure detection component; the fourth valve is opened to obtain the third air pressure data of the air pressure detection component.

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