CN205559110U - Measurable exhaust gas flow's venturi - Google Patents

Abstract

The utility model relates to a venturi especially relates to a measurable exhaust gas flow's venturi. Including EGR outlet duct, venturi, EGR outlet duct, temperature sensor, pressure sensor, differential pressure sensor, venturi divide into consecutive venturi entry, venturi aditus laryngis and venturi flaring section, be provided with the pressure sensor passageway on the venturi entry, link to each other with pressure sensor, the position that the venturi entry is close to the venturi aditus laryngis is provided with entry ressure measurement passageway, and the venturi aditus laryngis links to each other with aditus laryngis ressure measurement passageway, entry ressure measurement passageway and aditus laryngis ressure measurement passageway communicate with differential pressure sensor respectively. This device is through venturi import cross -section and wait pressure differential, the gas density in mouthful cross -section, utilizes bernoulli equation, thereby it obtains mass flow to calculate the gaseous volume flow rate of the pipeline of flowing through, realizes EGR system flow closed -loop control.

Description

A kind of Venturi tube surveying exhaust gas flow

Technical field

This utility model relates to a kind of Venturi tube, especially relates to a kind of Venturi tube surveying exhaust gas flow.

Background technology

Venturi tube (Venturi): be the abbreviation of Venturi tube, the principle of Venturi effect is then when blowing air over During obstacle, above the lee face of obstacle, near ports air pressure is relatively low, thus produces adsorption also Cause the flowing of air.The principle of Venturi tube is the simplest, and it is exactly air-flow from the coarse to fine, to accelerate gas Rate of flow of fluid, makes gas form " vacuum " district at the rear side of venturi outlet.

By the application of venturi in patent " supercharged diesel engine Venturi tube ERG ", solve High pressure EGR system EGR gas under Part load can not enter air inlet pipe, there is the problem that waste gas flows backwards, Realize preferable EGR rate under full working scope scope.Paper " utilizes Venturi tube and VNT to improve diesel engine EGR The research of rate " in utilize venturi reach improve EGR rate purpose." turbocharged and intercooled diesel engine egr system The design of Venturi tube and test " in determine Venturi tube throat diameter reach promote EGR rate purpose.

But in the paper either retrieved or patent, entirely description utilizes venturi can reach higher The purpose of EGR rate, does not has to measure the content of exhaust gas flow.

Utility model content

This utility model, by Venturi tube import cross section and the time pressure reduction in mouth cross section, gas density, utilizes uncle to exert Profit equation, calculates and flows through the volumetric flow of gas of pipeline thus obtain mass flow, it is achieved egr system flow Closed-loop Control Strategy, is that a kind of design that can utilize air flue reaches perception and measures the design poured in down a chimney of aerofluxus.

In order to reach object above, this utility model takes techniques below scheme, a kind of literary composition surveying exhaust gas flow Venturi, including EGR escape pipe, Venturi tube, EGR escape pipe II, temperature sensor, pressure transducer, Differential pressure pickup；EGR escape pipe is connected with Venturi tube two ends respectively with EGR escape pipe II；Temperature sensor It is arranged on EGR escape pipe；Venturi tube be divided into be sequentially connected venturi tube inlet, Venturi tube aditus laryngis and Venturi tube divergent segment；It is provided with pressure transducer passage on venturi tube inlet, is connected with pressure transducer； Venturi tube inlet is provided with inlet pressure Measurement channel, Venturi tube aditus laryngis near the position of Venturi tube aditus laryngis It is connected with aditus laryngis pressure measxurement passage；Inlet pressure Measurement channel and aditus laryngis pressure measxurement passage pass with pressure reduction respectively Sensor connects.

Further, being provided with chiller outside Venturi tube, chiller is placed on support；Chiller One end is connected with cooling water inlet pipe, and one end is connected with cooling water outlet pipe.

Further, EGR escape pipe is cooler for recycled exhaust gas outlet, is connected with venturi tube inlet；Venturi tube Divergent segment is connected with EGR escape pipe II.

This utility model is a kind of special Venturi tube, utilizes Bernoulli equation, by the pressure collected, temperature, Pressure difference signal is converted into EGR exhaust flow, thus realizes the accurate control to EGR valve.

This utility model Venturi tube is arranged between cooler for recycled exhaust gas outlet and air inlet pipe, and the system of application is useless Gas recirculating system, waste gas discharges from exhaustor, and major part is entered turbocharger acting, and fraction is by useless Gas recirculating system is transferred to air inlet and participates in the burning of a new round.

The utility model has the advantages that:

1, relatively with existing Venturi tube technology, this utility model adds the application of 3 kinds of sensors, uses In measuring exhaust gas flow, exhaustor can be recorded and pour in down a chimney operating mode, by demarcating, it is possible to achieve record exhaustor and pour in down a chimney Situation, prevention in the case of aerofluxus is poured in down a chimney, the unlatching of EGR valve；Can be obtained accurately by calculating simultaneously Exhaust gas flow, according to demarcation, can be used to control the aperture of EGR valve.

2, relative to existing Venturi tube, this utility model is many air flue and cooling water channels in terms of processing and fabricating.

3, one-body molded, it is not necessary to excessive zero parts, pipeline strong adaptability；This utility model integrated stand, pressure Power passage, pressure-differential passage, cooling water channel passage, in one, reduce assembling parts, simplification of flowsheet.

This utility model structure is originally intended to company 7L machine product, may extend to institute's organic type, relative to measurement The control of charge flow rate is measured, and the control mode contamination resistance utilizing this product is strong, low to pipeline installation requirement, Demarcate simple, reduce workload.

Accompanying drawing explanation

In order to be illustrated more clearly that this utility model embodiment or technical scheme of the prior art, below will be to reality Execute the required accompanying drawing used in example or description of the prior art to be briefly described, it should be apparent that, retouch below Accompanying drawing in stating is embodiments more of the present utility model, for those of ordinary skill in the art, is not paying On the premise of going out creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is structural representation of the present utility model；

Fig. 2 is the structural representation of this utility model Venturi tube；

1-EGR escape pipe in figure, 2-Venturi tube, 21-venturi tube inlet, 22-Venturi tube aditus laryngis, 23- Venturi tube divergent segment, 24-aditus laryngis pressure measxurement passage, 25-inlet pressure Measurement channel, 26-pressure sensing Device passage, 3-EGR escape pipe II, 4-temperature sensor, 5-pressure transducer, 6-differential pressure pickup, 7-is cold But water water inlet pipe, 8-cooling water outlet pipe, 9-support.

Detailed description of the invention

For making the purpose of this utility model embodiment, technical scheme and advantage clearer, below in conjunction with this reality With the accompanying drawing in new embodiment, the technical scheme in this utility model embodiment is clearly and completely retouched State, it is clear that described embodiment is a part of embodiment of this utility model rather than whole embodiments. Based on the embodiment in this utility model, those of ordinary skill in the art are not under making creative work premise The every other embodiment obtained, broadly falls into the scope of this utility model protection.

Embodiment 1:

Exhausted air quantity Computing Principle:

$Q_m=\frac{c}{\sqrt{1-{\mathrm{\β}}^4}}\mathrm{\ϵ}\frac{\mathrm{\π}}{4}{d}^2\sqrt{2\mathrm{\Δ}p\mathrm{\ρ}}$

In formula:

Q_mMass flow, by the exhaust mass of Venturi tube 2, units/kg/s in the unit interval；

C efflux coefficient, represents by the coefficient of relation between actual flow and the theoretical delivery of device；

β diameter ratio, the ratio of Venturi tube aditus laryngis 22 diameter and inlet diameter；

The ε coefficient of expansion；

D throat diameter, Venturi tube throat diameter, unit m；

Δ p pressure reduction, the differential static pressure that venturi tube inlet 21 and aditus laryngis record, this signal is passed by HCM pressure reduction Sensor is measured, unit Pa；

ρ waste gas density, by EGT and calculation of pressure, units/kg/m³。

According to calculating needs, venturi system needs three kinds of sensors, as it is shown in figure 1, one can survey waste gas The Venturi tube of flow, including EGR escape pipe 1, Venturi tube 2, EGR escape pipe II 3, temperature sensor 4, pressure transducer 5, differential pressure pickup 6；EGR escape pipe 1 and EGR escape pipe II 3 respectively with venturi Pipe 2 two ends are connected；Temperature sensor 4 is arranged on EGR escape pipe 1.

The operation principle of egr system is to utilize pressure reduction, i.e. exhaust gas pressure is higher than admission pressure so that waste gas is with new Fresh air mixes, and is again introduced into cylinder combustion, and under Part load, such as idling and towing astern operating mode, waste gas can not Entering air inlet pipe smoothly, there is the problem that waste gas flows backwards, in this case, common Venturi tube remains to just record Value, the flow now calculated should be negative, but system cannot distinguish between, according to the EGR of this status adjustment Valve opening certainly will be wrong.Can solve exhaustor pours in down a chimney the erroneous calculations brought to this utility model simultaneously.

This utility model Venturi tube is as in figure 2 it is shown, Venturi tube 2 is divided into the venturi tube inlet being sequentially connected 21, Venturi tube aditus laryngis 22 and Venturi tube divergent segment 23；It is provided with pressure on venturi tube inlet 21 to pass Sensor passage 26, is connected with pressure transducer 5；Venturi tube inlet 21 is near Venturi tube aditus laryngis 22 Position is provided with inlet pressure Measurement channel 25, Venturi tube aditus laryngis 22 and aditus laryngis pressure measxurement passage 24 phase Even；Inlet pressure Measurement channel 25 connects with differential pressure pickup 6 respectively with aditus laryngis pressure measxurement passage 24.

When waste gas forward flows through, owing to aditus laryngis pressure measxurement passage 24 is along air-flow, now gas pressure phase The pressure recording inlet pressure Measurement channel 25 is little, forms positive differential pressure.Contrary waste gas of working as flows counterflow through, by In aditus laryngis pressure measxurement passage 24 just to air-flow, at this moment pressure differential is abnormal increases, and can realize closing according to demarcating Close EGR valve, prevent false judgment.

Venturi tube 2 is outside is provided with chiller, and chiller is placed on support 9；Chiller one end with Cooling water inlet pipe 7 is connected, and one end is connected with cooling water outlet pipe 8.

EGR escape pipe 1 exports for cooler for recycled exhaust gas, is connected with venturi tube inlet 21；Venturi tube flaring Section 23 is connected with EGR escape pipe II 3.

Claims (3)

1. the Venturi tube that can survey exhaust gas flow, it is characterised in that: include EGR escape pipe (1), literary composition mound In manage (2), EGR escape pipe II (3), temperature sensor (4), pressure transducer (5), differential pressure pickup (6)；EGR escape pipe (1) is connected with Venturi tube (2) two ends respectively with EGR escape pipe II (3)； Temperature sensor (4) is arranged on EGR escape pipe (1)；Venturi tube (2) is divided into the literary composition being sequentially connected Venturi entrance (21), Venturi tube aditus laryngis (22) and Venturi tube divergent segment (23)；Venturi tube inlet (21) it is provided with pressure transducer passage (26) on, is connected with pressure transducer (5)；Venturi tube inlet (21) position near Venturi tube aditus laryngis (22) is provided with inlet pressure Measurement channel (25), venturi Pipe aditus laryngis (22) is connected with aditus laryngis pressure measxurement passage (24)；Inlet pressure Measurement channel (25) and aditus laryngis Pressure measxurement passage (24) connects with differential pressure pickup (6) respectively.

The Venturi tube of exhaust gas flow can be surveyed the most as claimed in claim 1, it is characterised in that: Venturi tube (2) Outside is provided with chiller, and chiller is placed on support (9)；Chiller one end and cooling water water inlet Pipe (7) is connected, and one end is connected with cooling water outlet pipe (8).

The Venturi tube of exhaust gas flow can be surveyed the most as claimed in claim 1, it is characterised in that: EGR escape pipe (1) it is cooler for recycled exhaust gas outlet, is connected with venturi tube inlet (21)；Venturi tube divergent segment (23) It is connected with EGR escape pipe II (3).