High-precision air flow meter for vehicle

Abstract

The utility model discloses a high-precision air flow meter for a vehicle. A first cavity and a second cavity which are separated by a fifth protruding strip are formed in the length direction of a body of the high-precision air flow meter for the vehicle. The second cavity is divided into a drainage air passage and a U-shaped measuring air passage by a fence; the body extends along the width direction to form an air inlet channel which is communicated with the inlet ends of the drainage air channel and the measurement air channel; the measuring chip is embedded in the measuring air channel and used for detecting the flow of air passing through the measuring air channel, a chip type sensor is adopted, the circuit board is embedded in the first cavity, and a main control chip is arranged on the circuit board; the main control chip is in communication connection with the measuring chip through a circuit on the circuit board; the cover plate covers the body and is used for sealing the openings of the first cavity, the drainage air channel and the measuring air channel in the thickness direction of the body. The device has the advantages of being high in metering precision and good in linear stability.

Description

Technical Field

[0001] The present application relates to the technical field of air flow meters, and particularly to a high-precision vehicle air flow meter. Background Art

[0002] The air flow meter is one of the most important components in a vehicle engine. It is used to monitor the air flow entering the engine and feedback the air flow parameters to the control system to cooperate with the fuel injection volume to ensure that the engine operates at a higher efficiency. Its basic principle is that the air flow enters the measurement air duct through the air inlet direction. When the air flow passes through the platinum resistor, it will take away part of the heat on the platinum resistor, resulting in a decrease in the temperature of the platinum resistor. The change in the temperature of the platinum resistor is proportional to the air flow passing through. The ECU indirectly measures the air flow by the magnitude of the current required to maintain the hot wire at a constant temperature. There are still some deficiencies in the air flow meters of the prior art. For example, the air flow meter based on the hot wire (platinum resistor) structure has a too large starting current and a large working power consumption; due to the deficiency in the structural design, the linearity of the air flow meter is poor, and the flow measurement is not accurate enough under low flow conditions and the air flow transient interference conditions at the initial stage of the engine intake stroke; after the cover is assembled with the flow meter body, it is connected by gluing, which requires a curing time, resulting in a long turnover time and low efficiency in the production process, and the volatilization of the adhesive has a certain impact on human health. Summary of the Invention

[0003] The purpose of the present application is to provide a high-precision vehicle air flow meter and its manufacturing process, which solves the problems in the prior art.

[0004] To achieve the above purpose, the present application provides the following technical solution: A high-precision vehicle air flow meter, comprising:

[0005] A body 1, in which a first cavity 101 and a second cavity 104 are formed and separated by a fifth rib 102 in the length direction; the second cavity 104 is separated by a baffle 108 to form a drainage air duct 106 and a U-shaped measurement air duct 105; an air inlet channel 109 is further formed on the body 1 extending in the width direction and communicating with the inlet ends of the drainage air duct 106 and the measurement air duct 105; a cut corner 107 is further formed on the body 1, and the ends of the drainage air duct 106 and the measurement air duct 105 are respectively opened on the two side walls adjacent to the cut corner 107;

[0006] A measurement chip 6, embedded in the measurement air duct 105 for detecting the air flow passing through the measurement air duct 105;

[0007] A circuit board 4, embedded in the first cavity 101, and a main control chip 5 is arranged on the circuit board 4; the main control chip 5 is communicatively connected to the measurement chip 6 through the circuit on the circuit board 4;

[0008] A cover plate 2, which is disposed on the body 1 and is used to seal the openings of the first cavity 101, the drainage airway 106 and the measurement airway 105 in the thickness direction of the body 1;

[0009] The enclosure 108 is formed by a second ridge 1082 and a fourth ridge 1084 which are parallel to the air flow direction in the air inlet channel 109 and are arranged at intervals, and a first ridge 1081 and a third ridge 1083 which are perpendicular to the air flow direction in the air inlet channel 109 and are arranged at intervals.

[0010] The air inlet channel 109 has a first side wall 1091 and a second side wall 1092 arranged at intervals, and a third side wall 1093 connected to the first side wall 1091 and with the end thereof inclined toward the second side wall 1092, the second side wall 1092 being coplanar with the side wall on the same side of the drainage airway 106; the third side wall 1093 has a tendency to guide the air entering from the air inlet channel 109 to the drainage airway 106; the end of the third side wall 1093 intersects with the adjacent side wall of the inlet of the measuring airway 105, and the intersection has an arc 1094;

[0011] The bottom surface of the measuring airway 105 is higher than the bottom surface of the air inlet channel 109 and there is a height difference e between the two, and the bottom surface of the air inlet channel is coplanar with the bottom surface of the drainage airway;

[0012] The side of the first convex strip 1081 facing the air inlet channel 109 is a convex arc surface facing the air inlet channel 109, and the measuring air channel 105 and the bottom surface of the air inlet channel 109 are connected by a reaction surface 1051. The projection of the reaction surface 1051 on the bottom surface of the air inlet channel 109 is a triangle, and the corner of the triangle facing the air inlet channel 109 intersects with the arc 1094, and the two sides of the angle respectively intersect with the two end points of the arc formed by the projection of the convex arc surface on the bottom surface of the air inlet channel 109; the reaction surface 1051 and the convex arc surface are jointly used to smooth out the transient peak interference of the airflow at the initial stage of the engine intake stroke.

[0013] Preferably, the body 1 is further formed with a third cavity 14 located beside the intersection of the first cavity 101 and the second cavity 104, a flange portion 12 connected to the outer end of the first cavity 101, and a connector portion 13 extending from the flange portion 12 on the opposite side of the third cavity 14, wherein the flange portion 12 is used to connect to the target intake pipe, and the connector portion 13 is used to connect to the control line plug of the engine control system;

[0014] A temperature sensor 7 is embedded in the third cavity 14. The third cavity 14 is in communication with the outside of the body 1. The temperature sensor 7 is used to detect the air temperature flowing through the body 1 in real time;

[0015] There are several power connection strips 3, which are embedded in the body 1 and are exposed at both ends in the connector part 13 and the first cavity 101 respectively;

[0016] The main control chip 5 is also electrically connected to the corresponding power connection strip 3 through the circuit on the circuit board 4.

[0017] Preferably, let the width of the diversion air passage 106 be c and the width of the measurement air passage 105 be d, then d = 2c; let the distance between the lower edge of the arc 1094 and the fourth convex strip 1084 on the side edge of the measurement air passage 105 be a, and the distance between the lower edge of the arc 1094 and the second convex strip 1082 on the side edge of the diversion air passage 106 be b, then b = 3a.

[0018] Preferably, the body 1 is further provided with a surrounding edge 15 that protrudes and at least surrounds three sides of the first cavity 101, and a convex platform 8 that is located on an extension line of one of the surrounding edges 15 and is spaced apart. There is a positioning cavity 9 between at least two adjacent surrounding edges 15. The cover plate 2 is a flat plate structure and is formed with a mating edge 203, a clamping groove 201, and an extension part 202 corresponding to the surrounding edge 15, the convex platform 8, and the positioning cavity 9 at the edge for clamping and positioning the cover plate 2 on the body 1.

[0019] Preferably, a weld seam 11 formed by laser welding is formed between the joint surfaces of the surrounding edge 15, the convex platform 8, the positioning cavity 9 and the corresponding mating edge 203, the clamping groove 201, and the extension part 202.

[0020] Preferably, two hollow openings 103 are spaced on the fifth convex strip 102. One of the hollow openings 103 is for the non-detection end of the measurement chip 6 to pass through and enter the first cavity 101 to be connected to the circuit board 4, and the other hollow opening 103 is closer to the cut corner 107;

[0021] The two hollow openings 103 also form an air passage for the first cavity 101 to dissipate heat.

[0022] The present application also provides a manufacturing process for a vehicle high-precision air flowmeter as described above, including the following steps:

[0023] A. The body 1 and the cover plate 2 are respectively formed by an injection molding process. When the body 1 is injection molded, the power connection strip 3 is also injection molded and embedded in the body 1;

[0024] B. Manufacture the circuit board 4 and solder the main control chip 5 onto the circuit board 4;

[0025] C. Burn a program into the main control chip 5 on the circuit board 4 and perform detection simultaneously;

[0026] D. Install the circuit board 4 made in step C into the first cavity 101, install the measurement chip 6 into the measurement air passage 105 and make its non-detection end pass through the fifth rib 102 to enter the first cavity 101 and abut against the circuit board 4, install the temperature sensor 7 into the third cavity 14, and solder the measurement chip 6, the circuit board 4, the temperature sensor 7, and the power connection strip 3 according to the set electrical connection relationship;

[0027] E. Conduct a range test on the vehicle-mounted high-precision air flow meter;

[0028] F. Conduct an aging test on the vehicle-mounted high-precision air flow meter that passes the test in step E;

[0029] G. For the vehicle-mounted high-precision air flow meter that passes the test in step F, inject fixing glue between the first cavity 101 and the circuit board 4 to fix the circuit board 4 and its attached components;

[0030] H. Install the cover plate 2 onto the body 1 and use laser welding to form the weld seam 11, completing the closure of the openings of the first cavity 101, the diversion air passage 106, and the measurement air passage 105 in the thickness direction of the body 1, so that the air inlet passage 109, the diversion air passage 106, and the measurement air passage 105 form a circumferentially closed air circulation passage;

[0031] I. Conduct a calibration test on the finished product of the vehicle-mounted high-precision air flow meter after step H.

[0032] Advantageous technical effects of the present application: The vehicle - use high - precision air flow meter of the present application is provided with a diversion air passage formed by enclosures and a U - shaped measurement air passage, and combines the combined action of a counter - impact surface and a convex arc surface formed at the inlet position of the measurement air passage to suppress the airflow transient peak interference at the initial stage of the engine's intake stroke, making the air flowing through the measurement air passage have a better correlation with the actual flow rate entering the engine, significantly reducing the measurement error, and thus improving the measurement accuracy of the air flow meter; by making the width of the measurement air passage greater than that of the diversion air passage and the measurement air passage is U - shaped, the air flow in the measurement air passage is stable and the contact surface between the air and the measurement chip is large, so that the air flow rate can be accurately measured even under small - flow conditions; by innovatively setting the distance between the lower circular arc edge and the fourth convex strip on the side edge of the measurement air passage to one - third of the distance between the lower circular arc edge and the second convex strip on the side edge of the diversion air passage, and setting the junction of the end of the third side wall and the adjacent side wall of the measurement air passage inlet as an arc, the airflow oscillation and shunt fluctuation when air enters the measurement air passage are effectively eliminated, ensuring the stable flow of air. At the same time, through the micro - negative pressure effect formed by the diversion air passage outlet at the measurement air passage outlet, the adhesion resistance formed by the inner surface of the measurement air passage to the air flowing in it is offset, further making the air throughput in the measurement air passage have a better correlation with the actual air flow rate entering the engine, significantly reducing the measurement error, and improving the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a three - dimensional structure schematic diagram of the vehicle - use high - precision air flow meter of the present application;

[0034] Figure 2 is an exploded view of the vehicle - use high - precision air flow meter of the present application;

[0035] Figure 3 is a partial three - dimensional view of the vehicle - use high - precision air flow meter of the present application after removing the cover plate;

[0036] Figure 4 is a front view of the vehicle - use high - precision air flow meter of the present application after removing the cover plate;

[0037] Figure 5 is a partial view of the vehicle - use high - precision air flow meter of the present application;

[0038] Figure 6 is a front view of the vehicle - use high - precision air flow meter of the present application;

[0039] Figure 7 is Figure 6 the cross - sectional view B - B in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0041] Please refer to Figures 1-7 , a high-precision vehicle air flow meter proposed by the present application includes: a main body 1, a measurement chip 6, and a circuit board 4. Among them,

[0042] A first cavity 101 and a second cavity 104 separated by a fifth rib 102 are formed in the length direction of the main body 1; the second cavity 104 is separated by a baffle 108 to form a diversion airway 106 and a U-shaped measurement airway 105; an air inlet channel 109 communicating with the diversion airway 106 and the inlet end of the measurement airway 105 is further formed on the main body 1 along the width direction; a cutout 107 is also formed on the main body 1, and the ends of the diversion airway 106 and the measurement airway 105 are respectively opened on the two side walls adjacent to the cutout 107. In this way, the air coming out of the diversion airway 106 forms a micro-negative pressure environment at the outlet of the measurement airway 105, generating a suction force on the air in the measurement airway 105 and effectively offsetting the flow resistance of the air in the measurement airway 105;

[0043] The measurement chip 6 is embedded in the measurement airway 105 and is used to detect the air flow rate passing through the measurement airway 105. By adopting a chip-type sensor, the accuracy of acquisition is improved, and the power required for the product is also greatly reduced. Since the hot film structure adopted by the measurement chip 6 has a maximum power consumption of only one-tenth of the minimum power consumption of a hot wire air flow meter, it has a significant energy-saving effect; since the measurement chip 6 has a packaging protection layer, the working life is effectively extended, the maintenance frequency and cost are reduced, and it has good linearity in a relatively wide flow range and can provide accurate measurement results under different conditions from low flow to high flow; since the heating and cooling speeds of the measurement chip 6 are relatively fast, it can quickly respond to air flow changes and is suitable for measuring rapidly changing air flows.

[0044] The circuit board 4 is embedded in the first cavity 101, and a main control chip 5 is arranged on the circuit board 4; the main control chip 5 is communicatively connected with the measurement chip 6 through the circuit on the circuit board 4;

[0045] A cover plate 2 is covered on the main body 1 to seal the openings of the first cavity 101, the diversion airway 106, and the measurement airway 105 in the thickness direction of the main body 1;

[0046] The enclosure 108 is formed by enclosing and surrounding the second rib 1082 and the fourth rib 1084 which are parallel to the air flow direction in the air inlet passage 109 and are spaced apart, and the first rib 1081 and the third rib 1083 which are perpendicular to the air flow direction in the air inlet passage 109 and are spaced apart. The thus formed enclosure 108 is a hollow beam structure and also has good support rigidity and strength, which is beneficial to maintaining the stability of the overall structure;

[0047] The air inlet passage 109 has a first side wall 1091, a second side wall 1092 which are spaced apart, and a third side wall 1093 which is connected to the first side wall 1091 and has an end inclined towards the second side wall 1092. The side wall of the second side wall 1092 on the same side as the drainage air passage 106 is coplanar; the third side wall 1093 has a tendency to direct the air entering from the air inlet passage 109 towards the drainage air passage 106. Thus, when the air pressure transient caused by the transient peak of the intake pressure at the beginning of the intake stroke of the engine causes a transient change in the air volume entering the air inlet passage 109 (at this time, due to the delay effect caused by the air filter on the engine intake system, the actual intake air volume does not increase instantaneously), a pressure flow that deflects the air flow is generated on the third side wall 1093 synchronously with this transient air to direct the air towards the drainage air passage 106. Since the width of the drainage air passage 106 is smaller than that of the air inlet passage 109, that is, the diameter of the drainage air passage 106 is smaller than that of the air inlet passage 109, in fact, the pressure at the inlet of the drainage air passage 106 is increased, that is, the pressure at the end of the air inlet passage 109 is increased. Thus, the pressure difference with the inlet of the air inlet passage 109 is reduced, thereby limiting the instantaneously increased air volume entering the air inlet passage 109. Similarly, the air volume entering the measurement air passage 105 is also prevented from mutating, so that the air volume flowing through the measurement air passage 105 is consistent with the actual intake air change of the engine air supply system, thereby improving the stability and measurement linearity of the vehicle high-precision air flow meter of the present application, and thus maintaining a high measurement accuracy; the end of the third side wall 1093 intersects with the adjacent side wall of the inlet of the measurement air passage 105 and there is an arc 1094 at the intersection. Through the arc 1094, the air entering the measurement air passage 105 from the air inlet passage 109 is prevented from oscillating and splitting fluctuations at the trailing edge there, so that the air entering the measurement air passage 105 is smooth;

[0048] Please refer to Figure 7 , the bottom surface of the measurement air passage 105 is higher than the bottom surface of the air inlet passage 109 and there is a height difference e between them. As a preferred embodiment, e can be set to 0.2 - 0.7 mm. In this embodiment, e is preferably 0.5 mm. The bottom surface of the air inlet passage 109 and the bottom surface of the drainage air passage 106 are coplanar, so as to keep the air flowing from the air inlet passage 109 into the drainage air passage 106 with a small flow resistance;

[0049] The side of the first convex strip 1081 facing the air inlet channel 109 is a convex arc surface facing the air inlet channel 109. The measuring air channel 105 and the bottom surface of the air inlet channel 109 are connected by a reaction surface 1051. The projection of the reaction surface 1051 on the bottom surface of the air inlet channel 109 is a triangle, and the angle of the triangle facing the air inlet channel 109 intersects with the arc 1094. The two sides of the angle intersect with the two end points of the arc formed by the projection of the convex arc surface on the bottom surface of the air inlet channel 109. It can be understood that the angle of the triangle facing the air inlet channel 109 can intersect with any theoretical point on the arc 1094; the reaction surface 1051 and the convex arc surface are used together to stabilize the engine The transient peak interference of the airflow at the beginning of the intake stroke is caused by the following principle: when the air rushing in from the air inlet channel 109 due to the transient suction force encounters the convex arc surface 1051 and the first convex strip 1081, they respectively generate reaction thrusts for the air to be directed toward the cover plate 2 and toward the air inlet channel 109. The combined force of the two directions urges the air to rebound back to the air inlet channel 109. At the same time, due to the action of the aforementioned third side wall 1093, the transient interference caused by the instantaneous influx of air into the measuring air duct 105 is further suppressed, so that the high-precision vehicle air flow meter of the present technical solution maintains a stable linear relationship with the actual air intake of the air supply system, thereby having better measurement accuracy.

[0050] As a preferred embodiment, please refer to Figures 1 to 7 The vehicle high-precision air flow meter of the present technical solution is further formed on the body 1 with a third cavity 14 located beside the intersection of the first cavity 101 and the second cavity 104, a flange portion 12 connected to the outer end of the first cavity 101, and a connector portion 13 extending from the flange portion 12 to the opposite side of the third cavity 14, the flange portion 12 is used to connect with the target intake pipe, and the connector portion 13 is used to connect with the control line plug of the engine control system;

[0051] The temperature sensor 7 is embedded in the third cavity 14, and the third cavity 14 is connected to the outside of the body 1. The temperature sensor 7 is used to detect the temperature of the air flowing through the body 1 in real time. In this way, the real-time temperature parameter of the air measured by the temperature sensor 7 is transmitted to the engine ECU as a basis for correcting the intake amount to ensure the efficiency of the engine;

[0052] There are several power bars 3, which are sealed in the body 1 and exposed at both ends in the connector part 13 and the first cavity 101. Here, the power bars 3 are usually made of copper stamping, and the number is usually 4, which are used to transmit air flow and temperature parameters to the ECU and supply power to the high-precision air flow meter for vehicles;

[0053] The main control chip 5 is also electrically connected to the corresponding power strip 3 through the circuit on the circuit board 4, and the main control chip 5 can adopt the existing technology.

[0054] As a preferred embodiment, please refer to Figures 1 to 7, assuming the width of the air guiding airway 106 is c and the width of the measuring airway 105 is d, then d = 2c; assuming the distance between the lower edge of the arc 1094 and the fourth rib 1084 on the side edge of the measuring airway 105 is a, and the distance between the lower edge of the arc 1094 and the second rib 1082 on the side edge of the air guiding airway 106 is b, then b = 3a. Through the above settings, on the one hand, it can ensure that air can smoothly enter the measuring airway 105 and flow stably in the measuring airway 105, and can well suppress the airflow transient peak interference at the initial stage of the engine intake stroke, effectively reducing unnecessary alarms or false alarms that may be caused.

[0055] As a preferred embodiment, please refer to Figures 1 to 7 , a surrounding edge 15 that protrudes and at least surrounds three sides of the first cavity 101 and bosses 8 that are located on an extension line of one surrounding edge 15 and are spaced apart are further provided on the body 1, and there is a positioning cavity 9 between at least two adjacent surrounding edges 15. The cover plate 2 is of a flat plate structure and has mating edges 203, clamping grooves 201, and extension parts 202 corresponding to the surrounding edge 15, the bosses 8, and the positioning cavity 9 at the edges for clamping and positioning the cover plate 2 on the body 1. Preferably, welding seams 11 formed by laser welding are formed between the joining surfaces of the surrounding edge 15, the bosses 8, the positioning cavity 9 and the corresponding mating edges 203, clamping grooves 201, and extension parts 202. Through the above settings, the cover plate 2 can be quickly installed and positioned on the body 1 during assembly, which is beneficial to improving production efficiency; at the same time, when laser welding is used at the joint of the cover plate 2 and the body 1, since the welding parameters are easy to accurately control and are not affected by the electromagnetic field, the welding process is stable, and high-quality and high-precision automated welding can be achieved, ensuring the consistency of the welding quality of the product; and the weld seam formed by laser welding is narrow and regular, with a small heat-affected zone and almost no spatter, and no grinding treatment is required after welding, which not only saves the time of subsequent processes but also ensures the aesthetics and surface quality of the welding area; at the same time, the curing time of the conventional adhesive process is not required, improving the efficiency and reducing the impact of the adhesive on the health of the operators.

[0056] As a preferred embodiment, please refer to Figures 1 to 7 , two hollow openings 103 are spaced on the fifth rib 102. One of the hollow openings 103 is used for the non-detection end of the measuring chip 6 to pass through and enter the first cavity 101 to be connected to the circuit board 4, and the other hollow opening 103 is closer to the cut corner 107; the two hollow openings 103 also constitute an air passage for dissipating heat from the first cavity 101, and the flowing air can be fully utilized to cool the circuit board 4 and the electronic components thereon.

[0057] This application also provides a manufacturing process for a vehicle-use high-precision air flow meter as described above, including the following steps:

[0058] A. The body 1 and the cover plate 2 are respectively formed by an injection molding process. When the body 1 is injection molded, the electrical connection bar 3 is also injection molded and embedded into the body 1.

[0059] B. The circuit board 4 is manufactured and the main control chip 5 is soldered onto the circuit board 4.

[0060] C. A program is burned into the main control chip 5 on the circuit board 4 while performing detection.

[0061] D. The circuit board 4 manufactured in step C is installed into the first cavity 101, the measurement chip 6 is installed into the measurement air passage 105 and its non-detection end passes through the fifth rib 102 and enters the first cavity 101 to abut against the circuit board 4, the temperature sensor 7 is installed into the third cavity 14, and the measurement chip 6, the circuit board 4, the temperature sensor 7, and the electrical connection bar 3 are welded according to the set electrical connection relationship.

[0062] E. A range test is performed on the vehicle-mounted high-precision air flow meter.

[0063] F. An aging test is performed on the vehicle-mounted high-precision air flow meter that has passed the test in step E.

[0064] G. For the vehicle-mounted high-precision air flow meter that has passed the test in step F, fixing glue is injected between the first cavity 101 and the circuit board 4 to fix the circuit board 4 and its attached components.

[0065] H. The cover plate 2 is installed onto the body 1 and welded by a laser welding method to form a weld seam 11, completing the sealing of the openings of the first cavity 101, the drainage air passage 106, and the measurement air passage 105 in the thickness direction of the body 1, so that the air inlet passage 109, the drainage air passage 106, and the measurement air passage 105 form a circumferentially closed air circulation passage.

[0066] I. A calibration test is performed on the finished vehicle-mounted high-precision air flow meter after step H.

[0067] In summary, the high-precision vehicle air flow meter of the present application is provided with a diversion air passage 106 formed by being separated by a retaining wall and a U-shaped measurement air passage 105, and combines the anti-excitation surface 1051 and the convex arc surface formed at the inlet position of the measurement air passage 105 to suppress the air flow transient peak interference at the initial stage of the engine intake stroke, so that the air flowing through the measurement air passage 105 has a better correlation with the actual flow rate entering the engine, significantly reducing the measurement error, thereby improving the measurement accuracy of the air flow meter; by making the width of the measurement air passage 105 greater than the width of the diversion air passage 106 and the measurement air passage 105 is U-shaped, the air flow in the measurement air passage 105 is stable and the contact surface between the air and the measurement chip 6 is large, so that the air flow rate can be accurately measured even under small flow conditions; by innovatively setting the distance between the lower edge of the arc 1094 and the fourth convex strip 1084 at the side edge of the measurement air passage 105 to be one-third of the distance between the lower edge of the arc 1094 and the second convex strip 1082 at the side edge of the diversion air passage 106, and setting the junction of the end of the third side wall 1093 and the adjacent side wall of the inlet of the measurement air passage 105 as the arc 1094, the air flow oscillation and shunt fluctuation when the air enters the measurement air passage 105 are effectively eliminated, ensuring the stable air flow. At the same time, through the micro-negative pressure effect formed by the outlet of the diversion air passage 106 at the outlet of the measurement air passage 105, the adhesion resistance formed by the inner surface of the measurement air passage 105 to the air flowing therein is offset, further making the air throughput in the measurement air passage 105 have a better correlation with the actual air flow rate entering the engine, significantly reducing the measurement error, and improving the measurement accuracy, far superior to the air flow meters of the prior art.

[0068] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0069] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0070] At the same time, the content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0071] Although embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A high-precision air flow meter for vehicles, characterized in that, Including: A body (1) having a first cavity (101) and a second cavity (104) separated by a fifth rib (102) in the length direction; the second cavity (104) is separated by a baffle (108) to form a drainage air passage (106) and a U-shaped measurement air passage (105); an air inlet passage (109) is further formed on the body (1) extending in the width direction and communicating with the inlet ends of the drainage air passage (106) and the measurement air passage (105); a cut corner (107) is further formed on the body (1), and the ends of the drainage air passage (106) and the measurement air passage (105) are respectively opened on two adjacent side walls of the cut corner (107); A measurement chip (6) installed in the measurement air passage (105) for detecting the air flow rate through the measurement air passage (105); A circuit board (4) installed in the first cavity (101), and a main control chip (5) is arranged on the circuit board (4); the main control chip (5) is communicatively connected to the measurement chip (6) through a circuit on the circuit board (4); A cover plate (2) covering the body (1) for closing the openings of the first cavity (101), the drainage air passage (106) and the measurement air passage (105) in the thickness direction of the body (1); The baffle (108) is enclosed by a second rib (1082) and a fourth rib (1084) arranged at intervals and parallel to the air flow direction in the air inlet passage (109), and a first rib (1081) and a third rib (1083) arranged at intervals and perpendicular to the air flow direction in the air inlet passage (109); The air inlet passage (109) has a first side wall (1091), a second side wall (1092) arranged at intervals, and a third side wall (1093) connected to the first side wall (1091) and inclined with its end facing the second side wall (1092), and the side wall of the second side wall (1092) on the same side as the drainage air passage (106) is coplanar; the third side wall (1093) has a tendency to direct the air entering from the air inlet passage (109) to the drainage air passage (106); the end of the third side wall (1093) intersects with the adjacent side wall of the inlet of the measurement air passage (105) and there is an arc (1094) at the intersection; The bottom surface of the measurement air passage (105) is higher than the bottom surface of the air inlet passage (109) and there is a height difference e between them, and the bottom surfaces of the air inlet passage (109) and the drainage air passage (106) are coplanar; The side surface of the first convex strip (1081) facing the air inlet channel (109) is a convex arc surface facing the air inlet channel (109); the measuring air channel (105) and the bottom surface of the air inlet channel (109) are connected by a reaction surface (1051); the projection of the reaction surface (1051) on the bottom surface of the air inlet channel (109) is a triangle, and the angle of the triangle facing the air inlet channel (109) intersects with the circular arc (1094); the two sides of the angle respectively intersect with the two end points of the arc formed by the projection of the convex arc surface on the bottom surface of the air inlet channel (109); the reaction surface (1051) and the convex arc surface are jointly used to smooth the transient peak interference of the airflow at the beginning of the engine intake stroke.

2. The high-precision air flow meter for vehicles according to claim 1, wherein: The body (1) is also formed with a third cavity (14) located beside the junction of the first cavity (101) and the second cavity (104), a flange portion (12) connected to the outer end of the first cavity (101), and a connector portion (13) extending from the flange portion (12) on the opposite side of the third cavity (14), the flange portion (12) being used to connect to a target intake pipe, and the connector portion (13) being used to connect to a control line plug of an engine control system; a temperature sensor (7) embedded in the third cavity (14); the third cavity (14) is in communication with the outside of the body (1); the temperature sensor (7) is used to detect the temperature of air flowing through the body (1) in real time; A plurality of power connection strips (3) are sealed in the body (1) and have two ends exposed in the connector portion (13) and the first cavity (101) respectively; The main control chip (5) is also electrically connected to the corresponding power strip (3) via the circuit on the circuit board (4).

3. The vehicle-mounted high-precision air flow meter according to claim 1, wherein: Assuming that the width of the drainage airway (106) is c and the width of the measuring airway (105) is d, then d=2c; assuming that the distance between the lower edge of the arc (1094) and the side edge of the fourth convex strip (1084) on the measuring airway (105) is a, and the distance between the lower edge of the arc (1094) and the side edge of the second convex strip (1082) on the drainage airway (106) is b, then b=3a.

4. The high-precision air flow meter for vehicle according to claim 1, wherein: The body (1) is also provided with a protruding edge (15) surrounding at least three sides of the first cavity (101) and bosses (8) located on an extension line of the edge (15) and arranged at intervals, wherein a positioning cavity (9) is provided between at least two adjacent edges (15), and the cover plate (2) is a flat plate structure and has a matching edge (203), a snap-fitting groove (201), and an extension portion (202) formed on its edge corresponding to the edge (15), the boss (8), and the positioning cavity (9) for snapping the cover plate (2) to the body (1).

5. The vehicle-mounted high-precision air flow meter according to claim 4, characterized in that: A welding seam (11) formed by laser welding is formed between the surrounding edge (15), the boss (8), the positioning cavity (9) and the corresponding mating edge (203), the snap-fit groove (201), and the connecting surface of the extension portion (202).

6. The vehicle-mounted high-precision air flow meter according to claim 1, characterized in that: Two hollow openings (103) are spaced apart on the fifth rib (102). One of the hollow openings (103) is for the non-detection end of the chip (6) to pass through and enter the first cavity (101) to be connected to the circuit board (4), and the other hollow opening (103) is closer to the notch (107); The two hollow openings (103) also form an air passage for heat dissipation of the first cavity (101).

Images