CN110126612A - A kind of enging cabin in clean gas car strengthens radiator structure - Google Patents
A kind of enging cabin in clean gas car strengthens radiator structure Download PDFInfo
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- CN110126612A CN110126612A CN201910467804.5A CN201910467804A CN110126612A CN 110126612 A CN110126612 A CN 110126612A CN 201910467804 A CN201910467804 A CN 201910467804A CN 110126612 A CN110126612 A CN 110126612A
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- cabin
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60K11/00—Arrangement in connection with cooling of propulsion units
- B60K11/02—Arrangement in connection with cooling of propulsion units with liquid cooling
- B60K11/04—Arrangement or mounting of radiators, radiator shutters, or radiator blinds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60K11/00—Arrangement in connection with cooling of propulsion units
- B60K11/06—Arrangement in connection with cooling of propulsion units with air cooling
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P11/00—Component parts, details, or accessories not provided for in, or of interest apart from, groups F01P1/00 - F01P9/00
- F01P11/10—Guiding or ducting cooling-air, to, or from, liquid-to-air heat exchangers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B29/00—Engines characterised by provision for charging or scavenging not provided for in groups F02B25/00, F02B27/00 or F02B33/00 - F02B39/00; Details thereof
- F02B29/04—Cooling of air intake supply
- F02B29/0406—Layout of the intake air cooling or coolant circuit
- F02B29/0425—Air cooled heat exchangers
- F02B29/0431—Details or means to guide the ambient air to the heat exchanger, e.g. having a fan, flaps, a bypass or a special location in the engine compartment
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Transportation (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Cooling, Air Intake And Gas Exhaust, And Fuel Tank Arrangements In Propulsion Units (AREA)
Abstract
The present invention discloses the enging cabin in a kind of clean gas car and strengthens radiator structure, including the air-inlet grille for being passed through cooling air in cabin, heat radiator assembly and air outlet for being cooled down to engine body and pressurized air, the cooling air flow direction of the heat radiator assembly is vertical with the direction of bus body length, and the air intake of heat radiator assembly faces the air-inlet grille that the side of bus body is arranged in；The air outlet be equipped with it is multiple, part of air outlet be provided with cabin top side on.The reinforcing radiator structure shortens the distance that cooling air out of my cabin flow to heat radiator assembly, improve the dissipating-heat environment around heat radiator assembly, achievees the purpose that strong radiator assembly Heat transfer boundary heat convection, improves flow velocity and flow that air in heat radiator assembly region flow to engine working area.
Description
Technical field
The present invention relates to automobile engine heat dissipation structures, and in particular to the enging cabin in a kind of clean gas car is strengthened
Radiator structure.
Background technique
It is especially set out in Report on the Work of the Governments in 2017 " to encourage to use clean energy vehicle, accelerate to push away in key area
Extensively use six regular fuel of state ".Clean fuel replaces the eco-friendly car of conventional fuel oil to be known as clean energy vehicle, at present automobile
Clean energy resource in addition to electric energy, further include the clean gas such as liquefied petroleum gas (LPG), liquefied natural gas (LNG).
Gaseous oil gas compares gasoline and easily mixes well with air to form the flammable gaseous mixture of homogeneous, and there is burning to fill
Point, CO and HC discharge low advantage, and its high-octane rating helps to promote engine compression ratio, and then improves the power of engine
With the thermal efficiency [1,2].But the ignition temperature of LPG is high, flame propagation velocity is slow, LPG urban bus engine is using single
Ignition operation mode in point injection, inlet manifold's mixing and cylinder, LPG combustion gas spark ignition type large bore engine power is big, stroke is long,
Combustion duration is long, influences the full combustion of gaseous mixture, and warm excessively high, the pinking tendency of engine row is easily caused under equivalent proportion and is increased
Add, engine heat load is big, proposes requirements at the higher level to heat dissipation in LPG gas engine cabin.Furthermore LPG enters cylinder with gaseous state
Shi Biran occupy partial cylinders volume, as intake air temperature is excessively high, can make engine volumetric efficiency reduction, and then influence LPG light
The dynamic property and economy of formula engine.Therefore, LPG fuel characteristic determines effective control of cabin temperature to engine power performance
Great influence.
Liquid fuel motor is compared, LPG gaseous propellant engine volumetric efficiency reduces about 10%, especially in city public affairs
It hands under car low-speed big operating condition, if weak heat-dissipating in cabin, engine volumetric efficiency is lower, and power decline certainly will become apparent from.Its
Secondary, LPG burning velocity is lower, and burning heel row temperature is high, need to strengthen the neighbouring heat convection of exhaust system in cabin.Furthermore LPG engine
Cabin structure arrangement is very compact, while urban bus is arranged using rear-engine cabin, it is not easy to by windward side incoming flow
Air is cooled down, and is caused the air capacity entered in cabin under equal conditions fewer than front engine, is brought to radiating of engine cabin
Bigger challenge.In conclusion LPG urban bus rear-engine cabin heat dissipation problem become domestic and international research focus it
One.
In enging cabin hemi-closure space, around engine compact Layout include radiator, intercooler, fan,
The important components such as engine breathing manifold, exhaust-driven turbo-charger exhaust-gas turbo charger, gearbox, air cleaner.Strengthening heat dissipation in cabin is one
Big challenge.Existing rear-mounted radiating of engine cabin structure is undesirable, for example, the enging cabin that is shown in Fig. 1 and Fig. 2 and its
Radiator structure, the cooling air runner design of the radiator structure is unreasonable, path is too long out of my cabin for hot-air discharge, leads to shape in cabin
At air swirl, return air by high-temperature component circulating-heating, hot-air is detained to form local high temperature zone, so as to cause in cabin
Heat dissipation effect is poor, causes the heat dissipation temperature difference of engine-cooling system to reduce, the high-temperature components such as engine body and intake and exhaust manifold
It cannot get the effective cooling, the decline of engine volumetric efficiency, a systems such as abnormal, lubricants performance variation of burning of high speed cold air
Column problem seriously affects LPG engine power performance.Therefore, it is designed through optimization radiating of engine cabin structure, in effective control cabinet
Flow field strengthens in cabin and radiates to dynamic property, economy and the feature of environmental protection for promoting automobile, there is its significance.
Summary of the invention
Above-mentioned it is an object of the invention to overcome the problems, such as, the enging cabin provided in a kind of clean gas car is strong
Change radiator structure, which shortens the distance that cooling air out of my cabin flow to heat radiator assembly, and it is total to improve radiator
At the dissipating-heat environment of surrounding, reaches strong radiator assembly Heat transfer boundary heat convection, improves air in heat radiator assembly region
It flow to the flow velocity of engine working area and the purpose of flow.
The purpose of the present invention is achieved through the following technical solutions:
A kind of enging cabin in clean gas car strengthens radiator structure, including for being passed through cooling air in cabin
Air-inlet grille, heat radiator assembly and air outlet for being cooled down to engine body and pressurized air, institute
The cooling air flow direction for stating heat radiator assembly is vertical with the direction of bus body length, and the air intake of heat radiator assembly faces
The air-inlet grille of the side of bus body is set；The air outlet be equipped with it is multiple, part of air outlet be provided with cabin top
On side.
The working principle that above-mentioned enging cabin strengthens radiator structure is:
Generally, clean gas bus works long hours in the operating condition of low-speed big, and engine generates very
Big heat, and the engine of car is generally postposition, so the heat dissipation performance for improving enging cabin is particularly important.Wherein,
In improved heat radiation performance, merely increase heat radiator assembly (intercooler and radiator) Heat transfer boundary flow not enough, herein
It is also desirable to optimize the radiator structure in cabin, the coupling of the multiple physical fields such as research air's velocity field, temperature field, temperature gradient field
The influence to heat dissipation performance in cabin, such as double influences of the vector matching degree to radiator heat-dissipation efficiency of Heat transfer boundary air are closed,
Find the matching degree of optimal air velocity vector and temperature gradient vector.
Specifically, this heat radiator assembly air flow direction it is vertical with the direction of bus body length, and air intake face
Be arranged in bus body side air-inlet grille, the air in outside can directly pass through air-inlet grille, and to enter radiator total
At to quickly be the gas in heat radiator assembly or liquid cooling.Further, due to the air velocity vector of this radiator with
The direction of bus body length is vertical, according to nusselt number it is found that the convection heat transfer intensity of this radiator structure is available larger
Reinforcing, wherein the expression formula of above-mentioned nusselt number are as follows:
In formula, Nu, Re, Pr are respectively nusselt number, Reynolds number and Prandtl number, and β is that heat radiator assembly Heat transfer boundary is empty
Gas velocity vector U and temperature gradient vectorBetween angle；From the expression formula of above-mentioned nusselt number it is found that reinforcing stimulus
There are three types of the approach of cabin heat radiator assembly Heat transfer boundary heat convection:
1) Reynolds number is improved, as increased radiator windward side flow velocity, reducing the leakage between air-inlet grille and heat radiator assembly
The methods of stream is to strengthen heat convection.
2) Prandtl number is improved, the specific heat perhaps stickiness as increased cooling fluid in cabin.
3) increase zero dimension integrated value
It wherein, is often to increase with the windward side flow velocity under operating condition, increasing heat radiator assembly in rear-mounted LPGB enging cabin
Adding fan energy consumption is cost, is had little significance to the raising of integral heat sink performance in cabin, can be by structural improvement in cabin come appropriate
Reduce the leakage current between air-inlet grille and heat radiator assembly；While cooling fluid is the sky of forced-convection heat transfer in enging cabin
Gas, specific heat capacity and viscosity are immutable.Therefore, when one timing of Reynolds number and Prandtl number, the Heat transfer boundary of heat radiator assembly
The intensity of heat convection depends entirely on the vector product of dimension air velocity and temperature gradient, expansion are as follows:
In formula, air velocity vector U and temperature gradient vectorBetween angle β it is smaller, then the Nu of heat convection is got over
Greatly；On the contrary, angle β is bigger, then Nu is smaller.Therefore, in order to strengthen heat convection, when the mould of velocity vector and temperature gradient vector
When fixed, the angle between the speed of cooling air and temperature gradient vector should be reduced as far as possible, this is proposed for field coordination principle
It is theoretical.
It is obvious that the angle β in the present invention can be close in 0 °, that is, the Nu of its corresponding heat convection can achieve most
Greatly (as U andOne timing), improve the heat dissipation performance in cabin.In contrast, existing radiating of engine cabin structure, referring to Fig. 3
It is found that air velocity vector U and temperature gradient vectorIt is close vertical, it follows that existing radiating of engine cabin structure
Heat loss through convection degree is smaller, and heat dissipation performance is poor.In addition, due to multiplying limitation of the position for transporting cabin heel row to enging cabin structure,
In order to avoid hot-air enging cabin top formed vortex, while make full use of hot-air rise, cold air sink the characteristics of,
Air outlet is arranged in the side on cabin top, and swimmingly hot-air can be discharged out of my cabin in this way.
A preferred embodiment of the invention, wherein the air-inlet grille includes inlet and grill, the grid and air inlet
Mouth is multiple, the gap composition air inlet between two neighboring grid；Multiple grids are arranged along the length direction of vehicle body
Column.
Preferably, lateral rear-inclined, inclination angle are 40 ° to the grid inside from the outside of vehicle body.When the inclination angle of air-inlet grille
When being 40 °, that is, the air in outside obliquely enters in cabin down along 40 °, enters the air of intercooler Heat transfer boundary at this time
Velocity vector with temperature gradient vector relatively match, the air velocity and temperature gradient vector angle β of radiator and intercooler are put down
Mean value is all smaller, corresponding with the big value of its Heat transfer boundary temperature gradient while the flow velocity of air improves, and meets Heat transfer boundary
Double vector Optimum Matchings strengthen heat dissipation principle.
A preferred embodiment of the invention, wherein the heat radiator assembly is an integral structure with air-inlet grille, in this way may be used
To avoid leakage current as far as possible, it is ensured that the air entered from air-inlet grille can be all followed by intercooler and radiator (radiator
Assembly), effectively cooling heat source.
A preferred embodiment of the invention, wherein air inlet of the outlet air end of the heat radiator assembly towards engine body
Manifold, compared with the prior art, referring to Fig. 1, the orientation of intercooler and radiator and the side where air-inlet grille are hung down
Directly, after air enters in cabin from the air-inlet grille of side, since air-inlet grille and engine body are equipped with partition, partition resistance
Air inlet is blocked, it is poor to the heat dissipation effect of engine body.Air-inlet grille is faced based on heat radiator assembly of the invention
Layout, this preferred embodiment eliminate partition, and the air come out from heat radiator assembly is allowed directly to blow to engine body, right
Engine body and its working region cool down, and reach strong radiator assembly Heat transfer boundary heat convection, improve radiator
Air flow to the flow velocity of engine working area and the purpose of flow in assembly region.
A preferred embodiment of the invention, wherein the heat radiator assembly is equipped with pod, mirror close to the side of engine
Air velocity near existing enmgine exhaust is relatively low, is unfavorable for the heat convection of Heat transfer boundary, is that this is preferred
In by setting pod, the high-speed flow guided engine front of part, reach exhaust manifold position around engine body
It sets, to improve the air matter flow and flow rate in this region, strengthens the heat convection of exhaust manifold Heat transfer boundary.
Compared with the prior art, the invention has the following beneficial effects:
1, strengthen heat dissipation principles based on the double vector Optimum Matchings of Heat transfer boundary, by heat radiator assembly face air-inlet grille into
Scenery resource quality shortens the distance that cooling air out of my cabin flow to heat radiator assembly, and improves the dissipating-heat environment around heat radiator assembly,
Improve radiator heat transfer availability.
2, due to multiplying limitation of the position of fortune cabin heel row to enging cabin structure, in order to avoid hot-air is on enging cabin top
Air outlet is arranged in the side on cabin top, in this way in the characteristics of forming vortex, while hot-air rising, cold air being made full use of to sink
Swimmingly hot-air can be discharged out of my cabin.
Detailed description of the invention
Fig. 1 is the sectional perspective structural schematic diagram of existing enging cabin, wherein engine is hidden in inside cabin.
Fig. 2 is the partial top view of existing enging cabin.
Fig. 3 is the air velocity vector U and temperature gradient vector of existing enging cabinBetween angle β schematic diagram.
Fig. 4-5 is the sectional perspective structural schematic diagram of two different perspectivess of the enging cabin in the present invention.
Fig. 6 is the partial top view of the air-inlet grille of the enging cabin in the present invention.
Fig. 7 is the vertical view air trajectory figure of existing enging cabin, wherein since air trajectory figure is to pass through simulation software
The view directly generated is only used for grayscale image expression.
Fig. 8 is the vertical view air trajectory figure of the enging cabin in the present invention.
Fig. 9 is the three-dimensional air trajectory figure of existing enging cabin.
Figure 10 is the three-dimensional air trajectory figure of the enging cabin in the present invention.
Figure 11 is section velocity vector field of the existing radiator structure in enging cabin Z=475mm.
Figure 12 is to strengthen radiator structure in the section velocity vector field of enging cabin Z=475mm in the present invention.
Figure 13 is section velocity vector field of the existing radiator structure in enging cabin X=38mm
Figure 14 is to strengthen radiator structure in the section velocity vector field of enging cabin X=38mm in the present invention.
Figure 15 is section velocity vector field of the existing radiator structure in enging cabin Y=810mm.
Figure 16 is to strengthen radiator structure in the section velocity vector field of enging cabin Y=810mm in the present invention.
Figure 17 is temperature field figure of the existing radiator structure in enging cabin Z=475mm.
Figure 18 is to strengthen radiator structure in the temperature field figure of enging cabin Z=475mm in the present invention.
Figure 19 is temperature field figure of the existing radiator structure in enging cabin X=38mm.
Figure 20 is to strengthen radiator structure in the temperature field figure of enging cabin X=38mm in the present invention.
Figure 21 is the angle of the air-inlet grille of the reinforcing radiator structure in the present invention and the effect picture of temperature.
Specific embodiment
In order to make those skilled in the art better understand technical solution of the present invention, below with reference to embodiment and attached drawing
The invention will be further described, but embodiments of the present invention are not limited only to this.
Referring to fig. 4-5, the enging cabin in the clean gas car in the present embodiment strengthens radiator structure, including for past
It is passed through the air-inlet grille 10 of cooling air in cabin and is dissipated for what is cooled down to engine body 1 and pressurized air
The cooling air flow direction of hot device assembly, the heat radiator assembly is vertical with the direction of bus body length, and heat radiator assembly
Air intake faces the air-inlet grille 10 that the side of bus body is arranged in.The heat radiator assembly includes intercooler 2, radiator
3 and fan 5, the intercooler 2 is connected to by cooling pipe with booster, to cool down pressurized air；It is described to dissipate
Hot device 3 is connected to by cooling pipe with engine body 1, to cool down inside it.Wherein, for driving wheel
The drive shaft 9 rolled is connect by intermediate propeller shaft with engine body 1, to realize the transmitting of power.
Referring to fig. 4-6, the air-inlet grille 10 is multiple, including inlet and grill；Multiple grids along vehicle body length
Spend direction arrangement, wherein the gap between two neighboring grid constitutes the air inlet.The grid is from the outside of vehicle body toward inside
It tilts backwards, inclination angle is 40 °.When the inclination angle of air-inlet grille 10 be 40 ° when, that is, the air in outside along 40 ° direction into
Enter in cabin, at this time into 2 Heat transfer boundary of intercooler air velocity vector with temperature gradient vector relatively match, 3 He of radiator
The air velocity and temperature gradient vector angle β average value of intercooler 2 are all smaller, while the flow velocity of air improves, with it
The big value of Heat transfer boundary temperature gradient is corresponding, meets the double vector Optimum Matchings of Heat transfer boundary and strengthens heat dissipation principle, later in principle
Middle detailed description.
Referring to fig. 4-5, the heat radiator assembly is an integral structure with air-inlet grille 10, and the air-inlet grille 10 offers
On the side plate of vehicle body, the heat radiator assembly is fixed on the inside of side plate by fixed connection structure.It in this way can be as far as possible
Avoid leakage current, it is ensured that from air-inlet grille 10 enter air can all followed by intercooler 2 and radiator 3, (radiator be total
At), effectively cooling heat source.
Referring to fig. 4-5, the air outlet of the heat radiator assembly faces the inlet manifold 6 of engine body 1.
And existing technology, referring to Fig. 1 and Fig. 2, orientation and the air-inlet grille of existing intercooler 2 and radiator 3
Side where 10 is vertical, after air enters in cabin from the air-inlet grille 10 of side, due to air-inlet grille 10 and engine sheet
Body 1 is equipped with partition 4, which stops air inlet, poor to the heat dissipation effect of engine body 1.Based on radiator of the invention
The layout for facing air-inlet grille 10 of assembly, this preferably eliminates partition 4, so that the air come out from heat radiator assembly can be with
Engine body 1 directly is blowed to, is cooled down to engine body 1 and its working region, the heat exchange of strong radiator assembly is reached
Air flow to the flow velocity of engine working area and the purpose of flow in boundary convection heat exchange, raising heat radiator assembly region.Its
In, the drive shaft 9 for driving wheel to be rolled is connect by intermediate propeller shaft with engine body 1, to realize power
Transmitting.
Referring to fig. 4-5, the heat radiator assembly is equipped with pod 5 close to the side of engine, in view of existing engine
Exhaust manifold 7 near air velocity it is relatively low, be unfavorable for the heat convection of Heat transfer boundary, for this preferably in by setting lead
The high-speed flow guided engine front of part is reached 7 position of exhaust manifold around engine body 1 by stream cover 5, to improve
The air matter flow and flow rate in this region strengthens the heat convection of 7 Heat transfer boundary of exhaust manifold.
Referring to fig. 4-5, the reinforcing radiator structure in the present embodiment further includes air outlet, the air outlet be equipped with it is multiple, wherein
Part air outlet is provided on the side on cabin top.Due to multiplying limitation of the position of fortune cabin heel row to enging cabin structure, in order to keep away
The characteristics of exempting from hot-air and form vortex on enging cabin top, while hot-air rising, cold air being made full use of to sink, on cabin top
Air outlet is arranged in side, and swimmingly hot-air can be discharged out of my cabin in this way.
Referring to fig. 4-5, the enging cabin in the present embodiment, which strengthens the working principle of radiator structure, is:
Generally, clean gas bus works long hours in the operating condition of low-speed big, and engine generates very
Big heat, and the engine of car is generally postposition, so the heat dissipation performance for improving enging cabin is particularly important.Wherein,
In improved heat radiation performance, merely increase heat radiator assembly (intercooler 2 and radiator 3) Heat transfer boundary flow not enough,
This it is also desirable to optimize the radiator structure in cabin, the multiple physical fields such as research air's velocity field, temperature field, temperature gradient field
The influence to heat dissipation performance in cabin, such as the double vector matching degree of Heat transfer boundary air are coupled to the shadow of 3 radiating efficiency of radiator
It rings, finds the matching degree of optimal air velocity vector and temperature gradient vector.
Specifically, this heat radiator assembly air flow direction it is vertical with the direction of bus body length, and air intake face
Be arranged in bus body side air-inlet grille 10, the air in outside can directly pass through air-inlet grille 10 and enter heat dissipation
Device assembly, to quickly be the gas in heat radiator assembly or liquid cooling.Further, due to the air velocity of this radiator 3
Vector is vertical with the direction of bus body length, that is, the angle between air velocity vector and temperature gradient vector can be close to
In 0 °.According to nusselt number it is found that the available biggish reinforcing of the convection heat transfer intensity of this radiator structure, wherein above-mentioned
The expression formula of nusselt number are as follows:
In formula, Nu, Re, Pr are respectively nusselt number, Reynolds number and Prandtl number, and β is that heat radiator assembly Heat transfer boundary is empty
Gas velocity vector U and temperature gradient vectorBetween angle；From the expression formula of above-mentioned nusselt number it is found that reinforcing stimulus
There are three types of the approach of cabin heat radiator assembly Heat transfer boundary heat convection:
1) Reynolds number is improved, as increased by 3 windward side flow velocity of radiator, reducing between air-inlet grille 10 and heat radiator assembly
The methods of leakage current is to strengthen heat convection.
2) Prandtl number is improved, the specific heat perhaps stickiness as increased cooling fluid in cabin.
3) increase zero dimension and integrate Cui
It wherein, is often to increase with the windward side flow velocity under operating condition, increasing heat radiator assembly in rear-mounted LPGB enging cabin
Adding 5 energy consumption of fan is cost, is had little significance to the raising of integral heat sink performance in cabin, can be by structural improvement in cabin come appropriate
Reduce the leakage current between air-inlet grille 10 and heat radiator assembly；While cooling fluid is the sky of forced-convection heat transfer in enging cabin
Gas, specific heat capacity and viscosity are immutable.Therefore, when one timing of Reynolds number and Prandtl number, the Heat transfer boundary of heat radiator assembly
The intensity of heat convection depends entirely on the vector product of dimension air velocity and temperature gradient, expansion are as follows:
In formula, air velocity vector U and temperature gradient vectorBetween angle β it is smaller, then the Nu of heat convection is got over
Greatly；On the contrary, angle β is bigger, then Nu is smaller.Therefore, in order to strengthen heat convection, when the mould of velocity vector and temperature gradient vector
When fixed, the angle between the speed of cooling air and temperature gradient vector should be reduced as far as possible, this is proposed for field coordination principle
It is theoretical.It is obvious that the angle β in the present invention can be close in 0 °, that is, the Nu of its corresponding heat convection can achieve maximum
(as U andOne timing), improve the heat dissipation performance in cabin.In contrast, existing radiating of engine cabin structure, can referring to Fig. 3
Know, air velocity vector U and temperature gradient vectorIt is close vertical, it follows that pair of existing radiating of engine cabin structure
Flow heat dissipation degree is smaller, and heat dissipation performance is poor.
In the present embodiment, the inclination angle of the air-inlet grille 10 is 40 °, is based on this inclination angle, and air enters heat radiator assembly
Air velocity and temperature gradient angle it is smaller.LPGB is set in one grade of straight-line travelling, engine speed 1451r/min,
It can be obtained according to relevant parameter:
Wherein, transmission ratio, base ratio and wheel diameter are given value, and the speed for acquiring car is 2.23m/
S, that is, enging cabin speed entrance numerical value.Therefore, in simulation process, the head on speed of incoming flow of car is -2.23m/s (- Y
Direction), the air of this speed enters in cabin from air inlet on the left of car through the swabbing action of fan, at 40 degree of grid inclination angles
Under guiding role, it can make that air velocity and temperature gradient angle in heat radiator assembly are smaller, direction is more consistent, synergy
More preferably.As shown in figure 21, under the action of the grid inclination angle of 40 degree of left sides, speed and temperature gradient angle in heat radiator assembly are more
It is small, it is more preferable to strengthen heat dissipation effect.
Further, due to eliminating partition 4, and pod 5 is set up, the air flowed out from radiator 3 can be made direct
Guidance effectively reinforces specific heat load into engine body 1 and its working region.Wherein, to engine body 1 and its work
The reinforcing heat dissipation in region can be divided into two parts: strengthen air flow channel speed in high-temperature component Heat transfer boundary heat convection and optimization cabin
Spend vector field and flow path.
1, strengthen high-temperature component Heat transfer boundary heat convection
The relational expression of the convection transfer rate h and nusselt number Nu on the high-temperature component surface of cabin intrinsic motivation working region are such as
Under:
H=Nu λ/L (1-1)
In formula, L is the geometric feature sizes of high temperature thermal component in cabin, unit m.
The expression formula of nusselt number is substituted into formula (1-1) to obtain:
For the enging cabin that structure is fixed, engine body 1, exhaust manifold 7 and other high-temperature components and air
Convection transfer rate h depends not only on the relevant reynolds number Re of air velocity, also with each spot speed on Heat transfer boundary in flow field and
The matching degree of temperature gradient vector is related.Thermal component such as exhaust manifold 7, exhaust pipe, useless positioned at 1 rear of engine body
Air turbine booster pump impeller etc., it is difficult to simple thoroughly to be solved by increasing cooling air flow velocity and flow, it is also necessary to from sky
Flow channel speed and the matching degree of Heat transfer boundary temperature gradient vector field set out to the influence angle of heat dissipation performance in cabin, research
Strengthen high-temperature component Heat transfer boundary heat convection new method.
2, optimize air flow channel velocity vector field and flow path in cabin
The cooling air of existing LPGB enging cabin typical structure path in cabin is too long, through recycling along journey high-temperature component
It is just reached near engine body 1 after heating.The design of unreasonable air flow channel makes engine body 1 and intake and exhaust manifold in cabin
7 equal high-temperature components cannot get effective cooling of big flow velocity cold air, and path is too long out of my cabin for hot-air discharge, cause to be formed in cabin empty
By high-temperature component circulating-heating, hot-air is detained the local high temperature zone to be formed near intake and exhaust manifold 7 for gas whirlpool, return air,
Heat dissipation performance is poor in cabin.In engine working area, reinforcing stimulus ontology 1 waits the Heat transfer boundary heat convection of high-temperature components
Meanwhile the inlet air flow path of air flow channel and discharge out of my cabin in cabin need to be optimized and tieed up simultaneously conducive to the lasting heat dissipation of high-temperature component
Hold air flow channel core flow area mean temperature is lower and uniform temperature fields are distributed, it is ensured that hot-air is passed with path as short as possible
It passs out out of my cabin.Solving that engine working area forms air swirl, reflux, hot-air are detained etc. leads to a series of excessively high of cabin temperature
Problem.
Cross increase member with thermoelectric ratio be according to introducing the physical quantity also known as heat product that one is named as fire product, be thermal capacity with
The half of temperature product:
In formula, QvhFor the heat capacity at constant volume of object, T is the temperature of object, and the heat product size of air transmits heat with it
Ability it is related, the dissipation of this ability, that is, heat product dissipates, and can indicate the irreversible loss of heat transfer process.
Unstable state, the energy conservation equation without inner heat source heat conduction problem are as follows:
The formula both sides (2-2) multiplied by temperature T and are deformed and can be obtained:
In conjunction with Fourier law, heat flow density:
In formula (2-4),It represents unit volume object heat product and changes over time rate,It is with heat
The heat product of amount transmitting transports,It is heat product dissipative term, represents in conduction process because irreversible caused by thermal resistance
Loss.
For the steady-state fluid Convective Heat Transfer of no inner heat source, energy equation can be expressed with vector form:
The both sides formula (2-5) are same to multiply temperature T
Wushu (2-6) deforms
In formula (2-7),It is defeated to represent the caused heat product of air micelle movement in Convective Heat Transfer
Fortune,The long-pending diffusion in inside air of heat is represented,Represent the dissipation of heat product.
The sum of in the equilibrium equation of heat product, the heat product that the variable quantity of heat product is equal to flows and heat product dissipates.
It dissipates from cabin inner flow passage core flow area heat productExpression formula discovery, in order to strengthen heat convection, runner
Atmospheric heat product in core flow area, which dissipates, wants small.The small value namely runner core flow of the small value corresponding temperature gradient-norm of heat product dissipation
Area air themperature field is more uniform, and thermal resistance is smaller, and above-mentioned rule meets the evaluation criterion using temperature uniformity as heat transfer intensity.
For heat convection along with the irreversible dissipation of heat product, the smallest direction of heat product dissipation is exactly energy transmission mistake
The optimal direction of journey.Rear-mounted clean gas bus radiating of engine cabin is poor, need to strengthen heat convection in cabin, improves in cabin
The heat-sinking capability of limited cooling air, for enging cabin containing various heating sources, flow passage structure is complicated and has multiple inlet and outlets, whole
Vehicle, which travels air drag, is influenced the features such as small by structure in cabin, proposes the engine working area air flow channel for being more suitable for the object
Core flow area's uniform temperature fieldsization strengthen heat dissipating method.This method constructs engine operation area by the Lagranian functional calculus of variations
Domain uniform temperature fieldsization strengthen heat dissipation model, and with the regional air runner core flow area, temperature gradient is minimised as optimization aim,
It is intended to change the additional volume force constraint in pure pressure-driven flow field to the addition of air momentum equation, obtains and improve air heat radiation energy
Power strengthens the optimum air runner velocity vector field to radiate in cabin and flow path.
Referring to Fig. 7-20, below from the data that obtain of experiment, respectively to inlet air flow path, analysis of Velocity Field and comprehensive
Heat dissipation performance is closed to be analyzed:
One, inlet air flow path
As shown in figures 7 and 9, in existing enging cabin, cooling air under the swabbing action of radiator 3, from left side into
Air port enters, and after flowing through the simultaneously heat sources such as cooling intercooler and radiator 3, from 3 rear of radiator, high speed flows out.But when due to outflow
The blocking of enging cabin rear door is encountered, partial air is trapped in 3 left back of radiator, forms high temperature whirlpool, part high speed gas
Stream then around air inlet cabin partition 4 reach engine working area, flow velocity thus substantially reduce, engine region formed it is longer inverse
Hour hands cool down path, are heated along journey by the high temperature part cycle such as intake and exhaust manifold 7 and discarded turbocharger.This strand of low speed, height
The heat that warm air is unfavorable for engine working area is transmitted to out of my cabin with shortest path in time, thus causes engine body 1 attached
Closely, the high-temperature region especially near inlet and outlet manifold 7.After remaining air is accelerated by radiator 3, directly from rear door and right cabin
Air outlet discharge at door, and cooling enging cabin high-temperature component not yet in effect.
As shown in figures 8 and 10, in the enging cabin in the present invention, a part is sent out from the high-speed flow that radiator 3 is discharged
The blocking of 1 left part of motivation ontology, directly flows out from the bilge, and another part air-flow then passes through the runner between motor intake manifold 6
It reaches near exhaust manifold 7, the high-temperature components such as direct cooled exhaust manifold 7 and exhaust-driven turbo-charger exhaust-gas turbo charger, most afterwards through right hatch door lattice
Grid are discharged out of my cabin with path as short as possible.Remaining air due to rear door barrier effect and turn to the bilge.With existing hair
Motivation cabin is compared, and air swirl is not present in the 3 assembly region of radiator of the enging cabin in the present invention, into the cooling sky in cabin
Gas flows to 6 front of inlet manifold with higher speed and shorter path.
Two, velocity field
As shown in figure 11, the left back of the heat radiator assembly in existing radiator structure is there are air swirl, engine
Air velocity near inlet manifold 6 and exhaust manifold 7 is below 3m/s, and there are three for the rear of exhaust manifold 7 and right
Apparent whirlpool.As shown in figure 12, in the reinforcing radiator structure in the present invention, air flow swirl is not generated at heat radiator assembly,
Flow velocity near heat radiator assembly is improved to 10m/s or more, and the fluid flow rate of the inlet manifold 6 of engine is also from original small
It improves in 3m/s to 7.5m/s or more, and also without generating air flow swirl, and exhaust manifold near the exhaust manifold 7 of engine
The air velocity vector and temperature gradient vector of 7 front and backs match, and heat dissipation performance improves.
As shown in Figs. 13 and 14, there are air flow swirls in the cabin top ladder in existing radiator structure, and in the present invention
Strengthen in radiator structure, the whirlpool in the ladder of cabin top has disappeared, and the flowing of heat convection air is more smooth, and hot-air is directly pushed up from cabin
Grid discharge.Moreover, the direction of cooling air velocity vector and temperature gradient vector is reached unanimity in depicted area, two vectors are big
It is worth corresponding, high flow rate cold air blows to cylinder cap wall surface, and quickly the heat of Heat transfer boundary high-temperature area is taken away, and it is inclined to destroy thermal resistance
High thermal boundary layer strengthens heat convection.
As shown in figs, an area in cabin top region for existing radiator structure and the air velocity in 2nd area are below
2m/s, and the air velocity in an area in the cabin top region of the reinforcing radiator structure in the present invention is 4.5m/s, the air stream in 2nd area
Speed is 12m/s, and the air velocity vector in mono- area Zhong of the present invention and 2nd area meets the Optimum Matching original of the double vectors of Heat transfer boundary
Then.
Three, comprehensive heat dissipation performance
As shown in FIG. 17 and 18, reflect the temperature gradient in the runner core flow area of the engine working area in two kinds of structures
Situation, the inlet manifold 6 and exhaust manifold 7 of existing radiator structure are formed about large area high-temperature region, are unfavorable for intake efficiency
Raising, also will increase engine knock tendency.Obviously, the engine working area runner of the reinforcing radiator structure in the present invention
The mean temperature in core flow area is lower, temperature gradient is smaller, more conducively reinforcing stimulus high-temperature component thermal boundary heat convection
Meanwhile heat is taken out of out of my cabin with shortest path, hence it is evident that improve radiating of engine cabin performance.
As shown in Figures 19 and 20, in existing radiator structure, due at the top of enging cabin there are ladder air swirl,
Make the cabin of engine push up hot-air to be detained, the high-temperature area at the top of cylinder cover to be up to 98 DEG C.Reinforcing in the present invention, which is radiated, ties
The cabin top hierarchic structure of the engine of structure and the temperature of cylinder cover area are substantially reduced to about 57 DEG C.
Above-mentioned is the preferable embodiment of the present invention, but embodiments of the present invention are not limited by the foregoing content,
His any changes, modifications, substitutions, combinations, simplifications done without departing from the spirit and principles of the present invention, should be
The substitute mode of effect, is included within the scope of the present invention.
Claims (6)
1. the enging cabin in a kind of clean gas car strengthens radiator structure, which is characterized in that including for being passed through in cabin
The air-inlet grille of cooling air, the heat radiator assembly for being cooled down to engine body and pressurized air and
Air outlet, the heat radiator assembly cooling air flow direction it is vertical with the direction of bus body length, and heat radiator assembly into
Wind rectifies the air-inlet grille against the side that bus body is arranged in；The air outlet be equipped with it is multiple, part of air outlet is opened
It is located on the side on cabin top.
2. the enging cabin in clean gas car according to claim 1 strengthens radiator structure, which is characterized in that described
Air-inlet grille includes inlet and grill, and the grid and air inlet are multiple, the gap composition between two neighboring grid
The air inlet；Multiple grids are arranged along the length direction of vehicle body.
3. the enging cabin in clean gas car according to claim 2 strengthens radiator structure, which is characterized in that described
Lateral rear-inclined, inclination angle are 40 ° to grid inside from the outside of vehicle body.
4. the enging cabin in clean gas car according to claim 1-3 strengthens radiator structure, feature
It is, the heat radiator assembly is an integral structure with air-inlet grille.
5. the enging cabin in clean gas car according to claim 1 strengthens radiator structure, which is characterized in that described
Inlet manifold of the outlet air end of heat radiator assembly towards engine body.
6. the enging cabin in clean gas car according to claim 1 strengthens radiator structure, which is characterized in that described
Heat radiator assembly is equipped with pod close to the side of engine.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111516485A (en) * | 2020-04-02 | 2020-08-11 | 东风柳州汽车有限公司 | Air guide structure of vehicle cabin |
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Application publication date: 20190816 |