CN85106537A - air flowmeter - Google Patents
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- CN85106537A CN85106537A CN 85106537 CN85106537A CN85106537A CN 85106537 A CN85106537 A CN 85106537A CN 85106537 CN85106537 CN 85106537 CN 85106537 A CN85106537 A CN 85106537A CN 85106537 A CN85106537 A CN 85106537A
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Abstract
Air flowmeter comprises an air flow measurement pipe that is positioned at main airway, and an air intake opening and gas outlet are arranged in the bypass of Xing Chenging therein.In fact air intake opening is positioned at the core of main airway section, and hot-wire airflow sensor is contained in the bypass.This air flowmeter is applicable to the internal combustion engine of motor vehicle.
Description
The present invention relates to the hot wire air flowmeter of bypass, the especially the sort of hot wire air flowmeter of measuring the internal combustion engine of motor vehicle intake air flow that is applicable to.
For instance, about being used for the hot-wire flowmeter of measuring machine motor-car intake air flow, at the SAE(Automotive Engineering Society) existing described in the technical report document 80048.This air mass flow in respect of one group not with the hot line of overcoat, be suspended on internal combustion engine and suck among the bypass of air-flow process, to measure air mass flow.Though the hot line with overcoat does not have the high advantage of response speed, defectiveness is because the back-fire in the air bypass makes them be damaged easily.
In order to overcome this defective, a several scheme had been proposed, for example Japanese patent publication 16259/82(is equivalent to DE-OS3019544) described in, adopt a kind of hot wire air flowmeter with Venturi tube, Venturi tube is contained in internal combustion engine and sucks in the main airway of air-flow process, bypass communicates with main airway, make and to shunt by the portion of air of main airway, utilize Venturi tube main airway upper reaches partly and near Venturi tube pressure differential between the main airway at narrow position, make the air-flow of process form one by-pass flow.In addition, also have a hot-wire airflow sensor that is contained in the bypass, monitor bypass gas flow,, determine to suck the flow of the whole air of internal combustion chamber according to the flow velocity that air flow sensor obtains.Employing has the hot wire air flowmeter of bypass that a problem is arranged: when tested air-flow was pulsating flow, the operating lag of hot line made to record the result less than the actual average air mass flow.In order to address this problem, Japanese patent publication 135916/83(is equivalent to United States Patent (USP) series number 461556) in a scheme was once proposed, make the distance between the air intake opening and gas outlet in the bypass, compare with the distance that measurement main airway axial distance obtains, increase to some extent, with the error in the compensating measure.In this hot wire air flowmeter, the air-flow that enters air flowmeter is divided into two strands at the air intake opening or the connecting port of bypass, has one air-flow to continue by main airway, and another burst air communication is crossed bypass, last these two strands of air-flows converge mutually in the gas outlet of bypass or the mouth that confluxes, and flow out air flowmeter.Air velocity by bypass is recorded with temp probe by the hot line probe.By the air velocity signal of the air flow sensor generation that detects air velocity in the bypass and by the relation between the whole air mass flows of air flowmeter, be predetermined, thereby can determine whole air mass flows according to the flow velocity signal that air flow sensor in the bypass produces.In order to ensure can through the air-flow of bypass and through the ratio between the air-flow of main airway,, also remaining constant with the flow of high precision acquisition by whole air of air flowmeter even wriggle through the flow of air flowmeter.
But this hot wire air flowmeter is not immaculate.When the tube wall of air flowmeter is heated, will be through the air mass flow of bypass less than air mass flow through main airway, thus make air themperature in the bypass be higher than air themperature in the main airway.Consequently, the air expansion in the bypass, bypass increases the resistance of air-flow, and the air mass flow that makes the process bypass at last is less than the air mass flow through main airway.Therefore, the hot wire air flowmeter of said structure has such defective: air flowmeter road wall cold and hot reduces the numerical precision of the air mass flow that air flowmeter records.
In the hot wire air flowmeter of said structure, be introduced in bypass by near that part of air-flow the main airway road wall, and survey inspection by air flow sensor.In general,, compare, be easier to form the perturbation air-flow with that part air-flow by the main airway center by near that part air-flow the main airway road wall.Like this,, will have higher noise/signal, because it is to be produced by that higher part air-flow of disturbance degree in the main airway than (N/S ratio) by the signal that hot-wire airflow sensor produced that detects air mass flow in the bypass.
This invention is intended to overcome the defective of above-mentioned original design.Therefore, the purpose of this invention is to provide and a kind ofly can obtain more high-precision hot wire air flowmeter when measuring air mass flow, the influence that it is not generated heat by main airway makes air flowmeter can produce the signal of low noise/signal ratio.
In order to achieve the above object, air mass flow involved in the present invention is in respect of an air flow measurement pipe that is contained in the main airway, and Guan Youyi air intake opening of this air flow measurement and gas outlet are as bypass; In addition, also have a hot line or an air flow sensor that is contained in the air flow measurement pipe, in fact this air flow sensor is contained in the center part of main airway section, in order to detect the air velocity through bypass.
Be the accompanying drawing summary below.
Fig. 1 is the planimetric map that comprises the air flowmeter of first device of the present invention;
Fig. 2 is the sectional view along the II among Fig. 1-the II line is got;
Fig. 3 is the sectional view along the III among Fig. 1-the III line is obtained;
Fig. 4 is the sectional view along the IV among Fig. 2-the IV line is obtained;
Relation between Fig. 5 curve representation air mass flow and the air-flow measurement error, one is to record according to air flowmeter of the present invention shown in Fig. 1～4, and the air flowmeter of the present technology of another basis records, and both road walls all are heated.
Fig. 6 curve representation in air flowmeter of the present invention shown in Fig. 1～4 and in the air flowmeter of present technology air mass flow and noise/signal than between relation;
Fig. 7 is the vertical cross section that comprises the air flowmeter of second device of the present invention;
Fig. 8 is the planimetric map that comprises the air flowmeter of the 3rd device of the present invention;
Fig. 9 is the sectional view along the IX among Fig. 8-the IX line is obtained;
Figure 10 is the sectional view along the X among Fig. 9-the X line is obtained;
Figure 11 is the sectional view along the XI among Fig. 9-the XI line is obtained;
Figure 12 is the planimetric map that comprises the air flowmeter of the 4th device of the present invention;
Figure 13 is the sectional view of establishing among Figure 12 that the X III-X III line is obtained;
Figure 14 is the sectional view along the V of the XI among Figure 13-XI V line is obtained;
Figure 15 is the planimetric map of air flowmeter of the present invention shown in Fig. 1～4, shows fuel injection valve simultaneously;
Figure 16 is the sectional view along the VI of the X among Figure 15-X VI line is obtained;
Figure and Figure 16 of Figure 17 are similar, but compare with Figure 16, and it is far away that the air flow measurement pipe is left in the position of ring;
Figure 18 is the planimetric map that comprises the air flowmeter of the 5th device of the present invention;
Figure 19 is the sectional view along the X of the XI among Figure 18-XI X line is obtained;
Figure 20 is the sectional view along the XX among Figure 18-the XX line is obtained;
Figure 21 is the planimetric map that comprises the air flowmeter of the 6th device of the present invention;
Figure 22 is the sectional view of establishing among Figure 21 that the X XII-X XII line is got;
Figure 23 is the sectional view along the III of the XX among Figure 22-XX III line is obtained;
Figure 24 is the planimetric map that comprises the air flowmeter of the 7th device of the present invention;
Figure 25 is the sectional view of establishing among Figure 24 that the XX V-XX V line is obtained;
Figure 26 is the sectional view along the VI of the XX among Figure 24-XX VI line is obtained;
Figure 27 is the vertical cross section that comprises the air flowmeter of the 8th device of the present invention;
Figure 28 is the sectional view along the VIII of the XX among Figure 27-XX VIII line is obtained;
Figure 29 is the vertical cross section that Figure 27 and device shown in Figure 28 improve the back air flowmeter;
Figure 30 is the sectional view along the XXX among Figure 29-the XXX line is got;
Figure 31 is the vertical cross section after the 3rd device shown in Fig. 8～11 improves;
Figure 32 is the sectional view along the XII of the XX among Figure 31-XX XII line is obtained;
Figure 33 is the backplan after the device shown in Figure 12～14 improves.
Be the explanation of optimum implementation below.
First device of the present invention can illustrate by Fig. 1～6.
According to Fig. 1 and Fig. 2, air flowmeter 1 comprises the air intake duct 8 of a definite wherein main airway 4, the Venturi tube 9 of formation air intake duct 8 inwalls, and is contained on Venturi tube 9 aditus laryngis and the air flow measurement pipe 10 vertical with airflow direction in the main airway 4.Air flow measurement pipe 10 1 ends are fixed in the air intake duct 8, are contained in to form Venturi tube 9 aditus laryngis recess 11 places partly, and the other end utilizes screw 13, and the bead 12A of the control assembly 12 by control circuit is housed is near the outer wall of air intake duct 8.The air intake opening of a connecting port 2 as bypass 3 arranged in air flow measurement pipe 10, its position is in fact on the central shaft of main airway 4, communicate perhaps in the center of main airway 4 sections part, and with the mouth 5 that confluxes, the latter is used as the gas outlet of bypass in air flow measurement pipe 10.The bypass 3 that forms in air flow measurement pipe 10 comprises: the air flue part 14 of first sensor, and it is adjacent with connecting port 2, in fact along the extension of central axis of main airway 4; The second air flue part 15, in fact it extend along the air flue 14 perpendicular directions of device sensor; The 3rd air flue 16, it is in fact along extending with the perpendicular direction of second air flue 15; The 4th air flue 17, it is in fact along extending with the perpendicular direction of the 3rd air flue 16, and with conflux mouthfuls 5 adjacently, be Fig. 2 and shown in Figure 3, this mouth 5 that confluxes is positioned at a side of air flow measurement pipe 10.Hot line probe 6 is Wound-rotor type with temp probe 7, is contained in the air flue 14 of device sensor.According to the connecting port 2 and the gas outlet of air intake opening that records along main airway 4 central shafts or bypass 3 or the distance between mouthfuls 5 of confluxing, the length of bypass 3 is greater than the length of main airway 4 in the said structure, and Fig. 3 and Fig. 4 show respectively along connecting port 2, bypass 3 in III-III among Fig. 2 and the section that IV-the IV line is obtained and mouthfuls 5 the relative position of confluxing.
Introduce the operating principle of first device among the present invention with said structure below.Enter the part air of air flowmeter 1, shown in arrow, enter bypass 3 through connecting port 2, mouthfuls 5 come out to enter main airway 4, converge with wherein air-flow from confluxing.Enter the air-flow of bypass 3, its flow velocity is recorded by hot line probe 6.Because the air mass flow of process bypass 3 is actually constant with the ratio of the air mass flow of process main airway 4, so just might be according to hot line 6 signals that produce of popping one's head in, through the air mass flow of main airway 4 and the relation between hot line probe 6 signals that produced, record air mass flow by pre-determined through main airway 4.
Be Fig. 1 and shown in Figure 2, determine that the air flow measurement device 10 of bypass 3 places among the air-flow of main airway 4.Therefore, even air intake duct 8 is subjected to the ectocine heating or when turning cold, in fact the pipe surface temperature of air flow measurement pipe 10 is consistent with air themperature through main airway 4.Like this, in fact the ratio of air mass flow of passing through bypass 3 and the air mass flow of passing through main airway 4 remained unchanged, no matter whether air intake duct 8 is heated.Like this, just got rid of the danger that measuring error takes place.
Fig. 5 show when air themperature be 20 ℃, when the pipe surface temperature of air intake duct 8 is 70 ℃ since air mass flow change and the test findings of issuable measuring error.In the air flowmeter of prior art, rise through the air themperature of bypass 3, thereby expand, particularly the tube wall when air intake duct 8 is heated, flow is hour even more serious.Air expansion reduces the flow through bypass 3, and consequently the value of hot line probe 6 signals that produced in the bypass 3 hangs down 5～10% than actual flow value.Yet in air flowmeter 1 of the present invention, above-mentioned error can be eliminated, because the air-flow of process bypass 3, in fact its temperature does not rise.
The test findings that Fig. 6 curve is represented, illustrated in the air flowmeter of the air flowmeter of this invention and prior art on the hot line probe 6 noise/signal of signal than and through the relation between the air mass flow of bypass 3.In air flowmeter 1 of the present invention, enter the center part of the air of bypass 3 from air-flow in the main airway 4, it generally can not produce rough air.Yet in the air flowmeter of prior art, be positioned at the outside of main airway on the main airway as the connecting port of bypass air intake opening.Therefore, enter the air-flow of bypass that part air-flow from close road wall in the main airway, its flow perturbation degree is higher.The test findings of Fig. 6 shows that in the air flowmeter of prior art, the signal that the hot line probe is produced, its noise/signal compare the noise/signal ratio that in fact is three times in hot line probe 6 generation signals in the air flowmeter 1 of the present invention.This is one of the most outstanding characteristics of the present invention.
The tolerance of air flowmeter of the present invention reduces greatly, thereby can carry out the batch process of air flowmeter.Especially the part of air intake duct 8 forms Venturi tube 9 by wall surface, and its aditus laryngis is through Precision Machining, and the outer surface of air flow measurement pipe 10 also passes through Precision Machining, and is identical with the aditus laryngis of Venturi tube 9.Utilize this version, can reduce to bottom line by the pressure differential of confluxing between the mouth 5 in connecting port 2 that causes through main airway 4 air-flows and the lie 3.For the variation through the air mass flow of bypass 3 that reduces that pressure differential thus causes, the some of bypass 3 must be done narrowlyer and through Precision Machining, make the resistance that air-flow produced through bypass 3 is all concentrated on the part that this narrows down.
Because the influence of natural convection, the performance of hot-wire airflow sensor is reduced to 0.5m/S in low-speed range.In order to start function to reach high-performance when the throttle wide, the resistance that air produced in 4 pairs of air flowmeter 1 of main airway should reduce, and so just needs to increase the basal area of main airway 4.Consequently, the air velocity at the air intake opening place of connecting port or bypass 3 reduces, and near the air velocity hot line probe 6 is step-down also.Like this, in order to reduce the change of air velocity in the bypass 3, and the flow velocity that improves near the air hot line probe 6, the air flue 14 of device sensor in the bypass 3, its basal area must narrow down to less than 80% of air flue in the bypass 3 15,16 and 17 basal areas.14 pairs of resistances that air produced of air flue that so just can the use device sensor determine to flow through the air mass flow of bypass 3, and air flue 14 is through precision machined.In addition and since the device sensor air flue 14 more tiny than air flue 15,16 and 17, might make first air flue or the device sensor air flue 14 in air velocity reach the highest.
Fig. 7 is the vertical cross section of second kind of air mass flow counter device proposing of the present invention.Air flowmeter 101 comprises the air intake duct 108 and structurally identical with an air flow measurement pipe shown in Figure 2 air flow measurement pipe 10 of a cylindricality, is inserted in the air intake duct 108.In this device, by the main airway 104 that air intake duct 108 is determined, its horizontal basal area reduces owing to having adorned the air flow measurement pipe in the air intake duct 108.Therefore, form a kind of negative pressure or sub-atmospheric pressures in conflux mouth 5 or bypass 3, the dynamic pressure that enters the air-flow generation of air flowmeter 101 acts on the air intake opening place of connecting port 2 or bypass 3.Consequently, through the air velocity of bypass 3, in fact with suitable through the air velocity of bypass 3 in the device illustrated in figures 1 and 2.
Fig. 8～11st, the 3rd device of the present invention.This air mass flow counter device 201 has an air intake duct same as shown in Figure 28, it comprises: air flow measurement pipe 210, wherein be formed with a bypass 203, bypass 203 is passed first air flue 214 longitudinally that is positioned at air intake duct 8 and is stretched from the connecting port 202 that is used as air intake opening; In fact second vertical with first air flue 214 air flue 215; And in fact with lead to mouthfuls 205 the 3rd vertical air flue 216 of second air flue 215 of confluxing, conflux mouthfuls 205 as the gas outlet, it is at a side opening of air flow measurement pipe 210.Hot line probe 206 is contained in respectively in second air flue 215 and the 3rd air flue 216 with temp probe 207.A recess 218 is arranged at the bottom of first air flue 214, therefore the air-flow that enters bypass 203 has turned over 90 degree through connecting port 202 in the terminal of first air flue 214, before entering main airway 204, enter second air flue 214 and the 3rd air flue 216 that hot line probe 206 and temp probe 207 are housed successively through the mouth 205 that confluxes.In the air flowmeter of this structure, the last stream of hot line probe 206 has changed direction, and therefore airborne dust is collected in the recess 218 of first air flue, 214 bottoms because inertia is separated.Because dust can not drop on the hot line probe 206, so just can not gather dust on the hot line probe 206, like this may be by accumulating in the pop one's head in signal drift of the air flow sensor that dust on 206 causes of hot line with regard to having reduced.
Figure 12～14 show the air flowmeter 301 that comprises the 4th device of the present invention.Air flowmeter 301 has an air intake duct same as shown in Figure 28, and it comprises: air flow measurement pipe 301, wherein be formed with a bypass 303, and it passes first air flue 314 longitudinally that is positioned at aspirating unit 8 and extends from the connecting port 302 that is used as air intake opening; In fact second vertical with first air flue 314 air flue 315, it manages 310 parallelly with leading to mouthfuls 305 the mensuration of confluxing, and confluxes mouthfuls 315 as the gas outlet, and it is at an end opening of second air flue 315 that is positioned at air flow measurement pipe 310 1 sides.Hot line probe 316 is contained in first air flue 314 with temp probe 317.In this device, the air-flow that flows into bypass 303 continues to flow through first air flue 314 of device sensor at connecting port 302 places, and when entering second air flue 315, air-flow changes direction.At this moment, air-flow is divided into the opposite two stocks stream of direction, enters by air intake duct 8 determined main airways by the mouth 5 that confluxes that five pores are arranged.Like this, bypass 314 has prolonged some, is easy to form in air flow measurement pipe 301.
Figure 15～17 show single-point oil spout chamber 19 and 19A, and wherein Fig. 1 matches with injection valve 20 with air flowmeter 1 of the present invention shown in Figure 2.Respectively there are an injection valve 20 and throttle valve 21 in oil spout chamber 19 with 19A, is positioned at the dirty of air flow measurement pipe 10.For the fuel oil that enters injection valve 20 is atomized better, injection valve 20, piezoelectric element 22, bugle shape spare 23 and ring 24 have been disposed, described in Japanese patent publication number 162972/84.The height H of single-point oil spout chamber 19 is limit control to some extent among Figure 16, makes injection valve 20 be in horizontal direction.In general, when injection valve was in horizontal direction, the fuel oil that enters injection valve was sprayed onto the wall on opposite easily, and aggregation there.In order to overcome this defective, taked to make the method for fuel-oil atmozation by the vibration of piezoelectric element 22, make the fuel oil that enters injection valve 20 be unlikely to be mapped to the wall of oil spout chamber 19.When utilize vibration make ring 24 that the fuel oil of accumulation atomizes and the gap between the air flow measurement pipe 10 than hour, be the T among Figure 16
1Shown in, air-flow is stopped that by air flow measurement pipe 10 therefore, the fuel oil that enters injection valve 20 is sprayed on the ring 24, utilizes vibration to atomize.When the gap between ring 24 and the air flow measurement pipe 10 is big, be the T among Figure 17
2Shown in, the atomized fuel particle that enters injection valve 20 is subjected to the effect of air-flow to be forced to flow downward, and shown in dotted line, is not sprayed on the ring 24.Therefore, make the ring 24 of the fuel-oil atmozation that enters injection valve 20 and the gap between the air flow measurement pipe 10 must keep very little.
Figure 18～20th, the 5th device of the present invention, wherein air flow measurement pipe 410 is parallel with main airway 4, is actually the center part that is positioned at air intake duct 8 inner chambers, forms a bypass 403, and bypass is actually along the central shaft of measuring pipe 410 to be passed through.Hot line probe 406 is contained in the bypass 403 with temp probe 407.
Air flow measurement pipe 410 has a connecting port 402 as air intake opening, in fact be positioned on the central shaft of main airway 4, communicate with annular bypass 408 from the dirty part of the bypass 403 of connecting port 402 beginning, it is parallel with mensuration pipe 10 along bypass 403, therefore, changeed one 180 degree through the air-flow that connecting port 402 enters bypass 403 in the terminal of bypass 403 from main airway 4, entered annular bypass 408 before entering main airway 4 through the mouth 405 that confluxes, the mouth that confluxes is positioned at a side of mensuration pipe 410 as the gas outlet.Hot line probe 4406 is contained among the bypass 403 with temp probe 407.
Air flow measurement pipe 410 by carriage 420 wherein a side link to each other with control assembly, the latter is fixed on the tube wall of air intake duct 8.The opposite side of measuring pipe 10 has a stay 421, can be contained on the tube wall of air intake duct 8 by screw thread, shown in 422 among the figure.The air that enters air flowmeter 401 from above is divided into two strands of air-flows at the connecting port as bypass 403 air intake openings.General gas continues by main airway 4, and another strand air-flow enters bypass 403.The air-flow process hot line probe 406 and temp probe 407 backs that enter bypass 403 flow into annular bypass 408, and process flows out as the mouth 405 that confluxes of gas outlet, and it enters main airway 4 in the aditus laryngis perforate of Venturi tube 9, and therefore two strands of air-flows are joined at the mouth 405 that confluxes.In this frame mode, in the length of bypass 403 and the air flow measurement pipe 410 at the ratio of the length (for the length L shown in Figure 19) of the connecting port 402 and the main airway 4 between mouthfuls 405 that confluxes, as long as select for use suitable annular bypass length can be set to arbitrary value.Like this, this ratio can increase by three to five times, thereby can reduce when the air-flow through bypass 403 is pulse pneumatic because hot line responds the error that falls behind and can cause.This stay 421 that utilizes is supported on device among main airway 4 air-flows with air flow measurement pipe 410, can make the temperature of air flow measurement pipe 410, and is in fact identical with air themperature through main airway 4, no matter air intake duct 8 is to be heated or to catch a cold.Like this, through the air-flow of bypass 403, its temperature is identical with air themperature through main airway 4 all the time, thereby has eliminated issuable error when measuring with hot line probe 406.The air-flow that enters bypass 403 by connecting port 402 is from the part of the center in the air-flow that enters air intake duct 8, and therefore, in fact the air-flow of process bypass 403 does not have rough air, and the signals that produced by hot line probe 406 have very low noise/signal ratio.
Figure 21～23rd, the 6th device of the present invention, wherein air flowmeter 501 has an air flow measurement pipe 510, and is similar with relevant parts shown in Figure 19, is supported among the air intake duct 8 by carriage 520 and stay 521.There are a bypass 503 and annular bypass 509 in air flow measurement pipe 510 inside, and they are made like this: the part bypass 504 of bypass 503 is surrounded by annular bypass 509, has in fact changeed 360 degree at garden Zhou Fangxiang.
Like this, enter air,, enter annular bypass 509 through wherein air intake opening 509A by the bypass 504 parallel with air flow measurement pipe 510 as the connecting port 502 of bypass 503 air intake openings.Through the air-flow of annular bypass 509, before entering main airway 4, make a circle mouthful 505 the aditus laryngis perforates of confluxing at Venturi tube 9 around bypass 503 by the mouth 505 that confluxes as bypass 5503 gas outlets.The annular distance shape is made in annular bypass 509, compared, might shorten the length L of air flow measurement pipe 510 with air flow measurement pipe 410 among Figure 19
1The relevant parts about installing among other parts of this device and Fig. 2 shown in Figure 22 are identical.Label 506 and 507 is represented hot line probe and temp probe respectively, and label 512 is control assemblies of air flow measurement pipe 510.
Figure 24～26 show the modified of device in Figure 18～20, have adorned a fair water fin 609 at the air intake opening of bypass 603, and air flow deflector is accumulated on the hot line probe 606 to avoid dust, and dust can reduce the precision that probe 606 is measured air velocity.
Shown air flowmeter 601 has an air flow measurement pipe 610 similar to the corresponding component of device shown in Figure 19, by carriage 620, one side and control assembly 612 link, and opposite side has a stay 621, by shown in the tube wall of screw thread 622 and air intake duct 8 link.In this air flowmeter 601, the bypass 603 that forms in the air flow measurement pipe 610, in fact similar with corresponding component shown in Figure 19, dissimilarity is that air intake opening 602 links to each other with annular bypass 608, and the mouth 605 that confluxes is arranged as the gas outlet.Hot line probe 606 is contained in the bypass 603 with temp probe 607.
This apparatus features is to utilize the fair water fin 609 that is positioned at as connecting port 602 places of bypass 603 air intake openings, makes air flow divert, accumulates on the hot line probe 606 to avoid dust.Utilize fair water fin 609, in fact the airflow direction with the process main airway is vertical to make the airflow direction that enters bypass 603.Therefore enter in the air of air flowmeter 601 most of dust owing to inertia enters main airway, thereby avoided entering bypass 603.Like this, just avoided dust to accumulate on the probe 606 and 607 of gas velocity in the decision bypass 603.
Figure 27 and 28 is the 8th devices of the present invention, and it comprises that is the air flow measurement pipe 510 shown in Figure 21～23, and the single-point injection valve 720 of band microcomputer.The parts that parts among Figure 27 and Figure 28 among those and Figure 22 are identical all mark with same label.Injection valve 720 is supported in the air intake duct 8 by stay 721, and the bottom of its top and air flow measurement pipe 510 links.The stay 521 of support air tube 510 is parallel to each other with the stay 721 that supports injection valve 510, and horizontal is in same direction.These two stays 521 and 721 all are fixed on the tube wall of the air intake duct 8 of determining mixing chamber.Adopt this structure, air can reduce through air flow measurement pipe 510 and injection valve 720 suffered resistances, and the height of mixing chamber can reduce.In Figure 27 and Figure 28, label 723,724 and 725 represents the throttle valve respectively, be used for the warm water that vaporization flow crosses the fuel oil of injection valve 720 adds thermal bypass and insulation material layer.The effect of insulation material layer 725 is to prevent injection valve 720 and mix the heating that locular wall 722 is subjected to warm water.
Figure 29 and Figure 30 are the modifieds of Figure 27 and device shown in Figure 28, wherein are positioned at the outside of injection valve 720 with the annular bypass 709 of bypass 703 contiguous, to reduce the height of the valve wall 720 of determining mixing chamber.The advantage of this device is that except the height that can reduce mixing chamber, its outer rim determines the outer diameter D of the injection valve 720 of annular bypass 709
2, greater than the outer diameter D of air flow measurement pipe 710
1, therefore do not need to resemble Venturi tube 9 of formation in main airway as shown in Figure 27.
Mention above, the temperature of air flow measurement pipe 710 is in fact the same with the temperature that wherein flows through air.When even air intake duct 8 is heated also for this reason.So just can adopt the very high synthetic resin material of plasticity to make air flow measurement pipe 710.When airflow has measured pipe 710 when being made by the synthetic resin material, the probe 706 and 707 that is positioned at bypass 703 can be made overcoat with layer of conductive material, can reduce noise like this.
Figure 31～33 show the modified of device shown in Figure 7, and wherein identical with parts shown in Figure 7 parts all mark with same label.Shown in figure, air flowmeter 101A comprises air flow measurement pipe 10A, forms bypass 3A therein, and bypass 3A has one in fact to be positioned at vertical first air flue 14A of main airway 104 centers part and the connecting port 2 that is used for bypass 3A air intake opening; It also has in fact vertical with vertical first air flue 14A radially second an air flue 15A.Mouthful 5A that confluxes is radially all arranged near the two ends of second air flue, and as the gas outlet of bypass 3A, the air-flow among the 3A is downward, and is perhaps parallel with main airway 104.
In the device of Fig. 7, as bypass 3 gas outlets conflux mouthfuls 5, have aperture at the offside of air flow measurement pipe 10, each hole towards main airway 104 radially.Therefore, enter bypass 3 by mouthfuls 5 air that enter main airway 104 at last that conflux, in fact to vertical direction, perhaps to main airway 104 in the direction that departs from of airflow direction spray, force air-flow in the main airway 104 towards the center of air intake duct 8 like this.This means that the air-flow that comes out to enter main airway 104 from bypass 3 is an obstacle to the air-flow through main airway 4, thereby dwindled the flow area of main airway 4.
In the modified shown in Figure 31～33, enter the air-flow of bypass 3A by connecting port 2, flow into vertical first air flue 14A, measure the flow velocity of air by wherein hot line probe 6 and temp probe 7.At air-flow before a mouthful 5A enters main airway 104 through confluxing, just be divided into the air-flow of two bursts of convection current at connecting port 16A, by the second air flue 15A radially.The dirty of air flow through in the conflux hole of mouthful 5A in main airway 104, therefore, enter the air of main airway 104 by mouthful 5A that confluxes, and flows to parallelly with the air that passes through main airway 104, flows through the resistance that main airway bears thereby reduced air.Its advantage is air can be flow through the resistance that main airway bears to drop to bottom line.
Claims (5)
1, air flowmeter, it comprises:
Main airway;
Bypass with described main airway UNICOM; And
Be contained in the hot-wire airflow sensor in the described bypass; It is characterized in that:
Be contained in the air flow measurement pipe in the described main airway, a described air flow measurement Guan Youyi air intake opening and gas outlet, in the air flow measurement pipe, form described bypass, described air intake opening is located substantially on the section center of described main airway, and described hot-wire airflow sensor is installed among the interior bypass of air flow measurement pipe.
2, according to the air flowmeter of claim 1, wherein said hot-wire airflow sensor comprises the probe of Wound-rotor type.
3, according to the air flowmeter of claim 1 or 2, wherein said air flow measurement pipe is horizontally installed among the described main airway.
4, according to claim 3 air flowmeter, wherein said bypass comprise one adjacent with described air intake opening, and first air flue parallel with described main airway, and second in fact vertical with described first air flue and parallel with a described air flow measurement pipe air flue, the two ends of described second air flue are adjacent with the described gas outlet aperture that is positioned at air flow measurement pipe both sides.
5, according to the air flowmeter of claim 1 or 2, wherein said air flow measurement pipe is parallel with described main airway.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 85106537 CN85106537A (en) | 1985-08-30 | 1985-08-30 | air flowmeter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 85106537 CN85106537A (en) | 1985-08-30 | 1985-08-30 | air flowmeter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN85106537A true CN85106537A (en) | 1987-03-18 |
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ID=4795129
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 85106537 Pending CN85106537A (en) | 1985-08-30 | 1985-08-30 | air flowmeter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN85106537A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100357711C (en) * | 2004-04-28 | 2007-12-26 | 株式会社电装 | Air flow rate measuring device having bypass passage |
| CN100376875C (en) * | 2002-11-18 | 2008-03-26 | 株式会社山武 | Fluid detection device |
| CN100424332C (en) * | 2006-09-08 | 2008-10-08 | 浙江麦姆龙仪表有限公司 | Device and method for measuring automobile engine air flow with self detection |
| CN100458125C (en) * | 2003-09-26 | 2009-02-04 | 株式会社京滨 | Intake device for internal combustion engine and method of measuring intake air amount |
-
1985
- 1985-08-30 CN CN 85106537 patent/CN85106537A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100376875C (en) * | 2002-11-18 | 2008-03-26 | 株式会社山武 | Fluid detection device |
| CN100458125C (en) * | 2003-09-26 | 2009-02-04 | 株式会社京滨 | Intake device for internal combustion engine and method of measuring intake air amount |
| CN100357711C (en) * | 2004-04-28 | 2007-12-26 | 株式会社电装 | Air flow rate measuring device having bypass passage |
| CN100424332C (en) * | 2006-09-08 | 2008-10-08 | 浙江麦姆龙仪表有限公司 | Device and method for measuring automobile engine air flow with self detection |
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