柴油机空调系统和冷却系统的关系
Analysis and simulation of mobile air conditioning system
coupled with engine cooling system
Zhao-gang Qi *,Jiang-ping Chen,Zhi-jiu Chen
Institute of Refrigeration and Cryogenics,School of Mechanical Engineering,Shanghai Jiao Tong University,
No.1954,Huashan Road,Shanghai 200030,PR China
Received 19September 2005;received in revised form 28March 2006;accepted 8October 2006
Available online 6December 2006
Abstract
Many components of the mobile air conditioning system and engine cooling system are closely interrelated and make up the vehicle climate control system.In the present paper,a vehicle climate control system model including air conditioning system and engine cooling system has been proposed under di?erent operational conditions.All the components have been modeled on the basis of experimental data.Based on the commercial software,a computer simulation procedure of the vehicle climate control system has been developed.The performance of the vehicle climate control system is simulated,and the calculational data have good agreement with experimental data.Furthermore,the vehicle climate control simulation results have been compared with an individual air conditioning system and engine cooling system.The in?uences between the mobile air conditioning system and the engine cooling system are discussed.ó2006Elsevier Ltd.All rights reserved.
Keywords:Air conditioning system;Engine cooling system;Coupled analysis;Simulation;Comparison
1.Introduction
A mobile air conditioning (MAC)system can supply drivers and passengers a safe and comfortable environ-ment.Perfect performance of the MAC is the target that automobile manufacturers pursue in the period of design and development.It is known very well that MAC can sup-ply cold capacity under summer operational conditions and waste heat of the engine is used to heat the passenger com-partment under winter operational conditions.For envi-ronmental factors,researches have been performed extensively to develop and improve the e?ciencies of MAC and engine cooling systems.Heat exchangers are the research emphasis of MAC and engine cooling systems.A lot of correlations,experiments and models about vari-ous heat exchangers have been proposed.Chang and Wang [1,2]and Chang et al.[3]developed thermal characteristics correlations related to the geometrical parameters of heat
exchangers with louvered ?ns.Their correlations have good agreement with their and previous experimental data in a wide range of Reynolds numbers based on louver pitch.Nowadays,many advanced technologies have been applied to enhance the performance of the heat exchangers of MAC and engine cooling systems.For engineers and researchers,the simulation procedure [4]of MAC and engine cooling systems can save test cost and manpower considerably.Raman Ali [5]developed a computer pro-gram for the MAC refrigerant circuit.The MAC included a condenser and an evaporator cooled by fans,a ?xed power reciprocating compressor and a thermostatic expan-sion valve.The heat transfer processes of the condenser and evaporator were divided into three parts as liquid,two phase and gas phase.All the nonlinear algebraic equa-tions were solved by iterative procedures.Saiz Jabardo et al.[6]proposed a steady computer program for an auto-mobile air conditioning system.The authors implied that operational parameters such as compressor speed,return air temperature in the evaporator and condensing air tem-peratures have an obvious e?ect on the performance of a
0196-8904/$-see front matter ó2006Elsevier Ltd.All rights reserved.doi:10.1016/j.enconman.2006.10.005
*
Corresponding author.Tel.:+862162933242;fax:+862162632601.E-mail address:qizhaogang@https://www.sodocs.net/doc/70277691.html, (Z.-g.Qi).
https://www.sodocs.net/doc/70277691.html,/locate/enconman
Energy Conversion and Management 48(2007)
1176–1184
MAC system.Calculational results deviated from the experimentally obtained results within a20%range,though most of them were within a10%range.Lee and Yoo[7] analyzed all the components under various operational conditions and proposed a MAC system model,which sim-ulated the performance of the integrated automobile air conditioning system very well.The component models were dependent on empirical correlations and previous proce-dures.For the engine cooling system,few literatures have been published because of commercial secrets.Bi et al.[8] developed a simulation model of the cooling air?ow for armored vehicle engines based on one dimensional tran-sient compressible?ow equations.Many in?uential factors had been taken into account in the model.In most litera-tures,the MAC and engine cooling systems are studied individually.In fact,many components of the MAC and engine cooling systems are closely interrelated to each other.With any change of vehicle speed,for example,the air?ow through the condenser changes,a?ecting the whole air conditioning system including the vehicle compartment and engine cooling system.
To avoid the above mentioned problems,an integrated system of mobile air conditioning system coupled with the engine cooling system,which is called the vehicle cli-mate control system,would be necessary.The targets of this study are to numerically analyze the in?uences of the engine cooling system on the mobile air conditioning sys-tem and to determine the main operational parameters a?ecting the vehicle climate control system performance. In the present paper,all the components of the vehicle cli-mate control system are analyzed based on the previous correlations and experimental data.A computer program consisting of the MAC and engine cooling systems is devel-oped to simulate the performance of the vehicle climate control system.
2.Analysis of vehicle climate control system
In the present study,a simulation model of the vehicle climate control system is to be constructed,which consists of a mobile air conditioning system and an engine cooling system.The mobile air conditioning system is mainly com-posed of a laminated evaporator,a parallel?ow condenser, a?xed displacement reciprocating compressor and an externally equalized thermostatic expansion valve.The engine cooling system is mainly composed of an engine,a serpentine type radiator and a tube in tube oil cooler,as schematically shown in Fig.1.In this vehicle climate con-
Nomenclature
A area(m2)
c1,c2constant(dimensionless)
c p speci?c heat(Jkgà1Kà1)
f Fannin
g friction factor,dimensionless
f1,f2,f3correlation de?ned as Reference[3]
F d?ow depth(m)
h speci?c enthalpy(J kgà1)
D h speci?c enthalpy di?erence(J kgà1)
j Colburn factor,dimensionless
L l louver length(m)
L p louver pitch(m)
g e?ciency,dimensionless
d thickness(m)
h louver angle,degree
e heat exchanger e?ectiveness,dimensionless Subscripts
ad adiabatic
air air side
com compressor
coolant coolant side
dis discharge of compressor
f?n
?c?ctitious property of saturated air calculated at refrigerant’s temperature
_m mass?ow rate(kg sà1)
NTU number of transfer units,dimensionless
N compressor speed(rpm)P power(W)
D P pressure drop(Pa)
Q heat transfer rate(W)
Re Lp Reynolds number based on louver pitch
T temperature(K)
D T temperature di?erence(K)
T d tube width(m)
T p tube pitch(m)
U overall heat transfer coe?cient(W mà2kà1) fri frictional
grav gravitational
in inlet/inside
local local
lm mean logarithmic method
max maximum
me mechanical
min minimum
mom momentum
out outlet/outside
ref refrigerant side
suc suction of compressor
tot total
V compressor displacement(m3)
v volumetric
wet wet condition
Greek letters
q density(kg mà3)
Z.-g.Qi et al./Energy Conversion and Management48(2007)1176–11841177
trol system,the operational parameters that can a?ect the system performance are vehicle speed,air temperature and velocity at the inlet of the condenser and the air tem-perature,humidity and volumetric ?ow at the inlet of the evaporator.
In order to reduce the complexity of the simulation models,the commercial software named KULI is applied to help the authors simulate the vehicle climate control sys-tem.All the models of the components in the vehicle cli-mate control system are proposed based on enormous experimental data.
2.1.Heat exchanger model of MAC system
For calculation of the heat transfer and pressure drop,the evaporator is divided into discrete area elements with their corresponding air and refrigerant mass ?ows [9,13,14].The changes of the variables of each element can be described by discrete di?erential equations.The equations are available from two energy balances (air side and refrigerant side).For the dry heat transfer rate of the air side,it is possible to use the following expression [10]:q tot ?U áA áD T lm e1T
where D T lm ?
T air ;in àT air ;out
ln T ref àT air ;out
ref air ;in
e2Tand U is the global heat transfer coe?cient evaluated at the mean properties of the element,which incorporates the in?uences of the heat transfer coe?cients of the air side and refrigerant side and the tube and ?n thermal resistances.
The air side heat transfer and friction characteristics can be characterized by the j and f factors of a heat exchanger,respectively.The following correlation was
suggested by Chang and Wang [2]and Chang et al.[3]to obtain the air side heat transfer coe?cient through the louver ?n:
j ?1:18Re à0:505
Lp
h 90 0:26F p L p à0:51T d L p à0:26L l L p
0:82
?T p L p à0:25d f L p à0:097e3T
f ?f 1?f 2?f 3
e4T
The correlations of the heat transfer coe?cient of the refrigerant side are derived from Refs.[11,12].
Because the air is cooled down in the evaporator and condensation can occur,it is necessary that a mass exchange should also be considered.It is based on an anal-ogy of the expression used in dry coils,while for wet coils,the mean logarithmic enthalpy di?erence is used instead.The heat transfer rate of a wet coil discrete element is given as follows:q wet ;tot ?_m air áD h lm e5T
where D h lm ?
h air ;in àh air ;out ln h ref ;fic àh air ;out
ref ;fic air ;in
e6TThe pressure drop of the refrigerant side can be expressed in the following equation:D P tot ?D P fri tD P mom tD P grav tD P local
e7T
where D P grav =0because the refrigerant ?ow direction is horizontal.The detailed correlations of D P fri ,D P mom ,and D P local are derived from Ref.[13].
The correlations above are the basis of the simulation,and the calculational data will be corrected according to the speci?c type and geometry of the heat exchanger and the experimental
data.
Fig.1.Mobile air conditioning system coupled with engine cooling system.
1178Z.-g.Qi et al./Energy Conversion and Management 48(2007)1176–1184
The mathematical model for the condenser is very simi-lar to that of the evaporator.The functions and techniques used in the evaporator are adapted to the condenser.How-ever,the formulas for the inner heat transfer coe?cients are quite di?erent.
https://www.sodocs.net/doc/70277691.html,pressor model
The compressor model is essentially constructed by the characteristics curves.A lot of volumetric e?ciency and isentropic e?ciency curves were obtained from experi-ments.The mass?ow rate of refrigerant in the compression process is derived from the following equation:
_m ref?g váq sucánáV dise8Twhere g v is obtained from the characteristic curves of vol-umetric e?ciency.The compressor power is obtained from
P com?_m refáeh dis;adàh sucT
g
me
e9T
To simplify the compressor model,the mechanical e?-ciency of the compressor is described as the following equa-tion based on the tested compressor:
g
me
?c1tc2lne_m=_m maxTe10Twhere c1=0.8728and c2=0.1777.
2.3.Expansion device model
Fig.2shows the characteristic curve of the expansion valve.During normal operational conditions,the exter-nally equalized thermostatic expansion valve keeps the superheating degree at the exit of the evaporator?xed at 5°C.On the basis of an adiabatic throttling,it follows that no change of the enthalpy of the refrigerant takes place in the expansion valve.The mass?ow equation is drawn from the Bernoulli equation and the adiabatic assumption as follows:_m ref?A miná
?????????????????????????????????
2q minep inàp outT
p
e11TThe analysis algorithms provide at any time that the characteristic curve for the superheat temperature is observed.The pressure drop of the expansion valve is not specially modeled.The pressure drop of the expansion valve results from the equalization process of the MAC circuit.
2.4.Engine model
The engine represents the most important heat source of a vehicle,and therefore,it is essential that the model of the engine should predict the heat?ows precisely.The com-plexity of the combustion process as an initial heat source, the heat?ows in the engine structure and the heat transfers to?uids and the surrounding air make the set up of this kind of model a very di?cult task.
In this study,the engine simulation model contains all relevant heat sources and heat transfer areas to calculate the heat impact on the coolant circuit,the oil circuit, and the engine structure(Fig.3)[14].The model contains three heat sources,one for the heat?ow related to the coolant circuit,one for the heat?ow to the oil circuit and one for the friction.The measurement of the heat ?ow in the cabin heater can be used to adjust the heat ?ow to the coolant because the heater will represent the main heat sink as long as the thermostat directs no?ow to the radiator.The heat?ow of the engine to the cool-ant,depending on engine speed and load,can be inte-grated in the simulation model using a heat?ow map based on measured data.Similarly,utilizing the heat transfer data in the engine oil cooler,the heat?ow to the oil circuit can be determined.
The oil temperature and the oil viscosity are important for calculation of the friction loss.The di?erence in the heating behavior of the oil and the coolant leads to a var-iable heat?ow from the oil to the
coolant.
Fig.2.Characteristic curve of externally equalized thermostatic expansion valve.
Z.-g.Qi et al./Energy Conversion and Management48(2007)1176–11841179
2.5.Heat exchangers of engine cooling system
There is no phase change happening in the heat exchangers used in the engine cooling system.Pressure drops in the radiator and oil cooler are negligible.The models of the two heat exchangers are described using the e-NTU method[15].The heat transfer performance of the heat exchangers is given by the following equation:
q?e_mc pT
min
áeT coolant;inàT air;inTe12T2.6.Other models
Other additional components in the MAC and engine cooling systems are modeled based on the experimental data of the KULI models database[16,17].The e?ects of connective tubes and receiver dryer in the vehicle climate control system are considered negligible.
2.7.Uncertainty analysis
The system model is composed of a number of compo-nents,each of which is modeled on the basis of much experimental data.Each component is modeled individu-ally and compared with the experimental data.These comparable data derive from steady state experiments. The inaccuracy of the component models is shown in Table1.Each component model brings an inaccuracy into the system model.The uncertainty of the predictions of the complete model is estimated by the method sug-gested by Mo?at[18].The average uncertainties of the evaporator capacity of the MAC and the coolant temper-ature at the exit of the radiator are6.5%and7.8%at a steady condition,
respectively. Fig.3.Engine simulation model.
Table1
The average inaccuracy of each component at steady condition Components Inaccuracy
Evaporator 5.2%(evaporator capacity),6.8%(pressure drop) Condenser 4.8%(condenser capacity),7.6%(pressure drop) Compressor7.2%(discharge pressure),10.2%(power) Expansion device 2.0%(quality at the exit of expansion device) Engine9.8%(combustion heat),torque(12.6%) Radiator 5.4%(heat output)
Oil cooler9.0%(heat output)
Fans 3.8%(volume?ow rate of
air)Fig.4.Schematic diagram of environmental simulation equipment of MAC.
Table2
Some main components’geometries
Components Style Geometry
Evaporator Laminated125mm·250mm·90mm Condenser Parallel?ow600mm·455mm·20mm Compressor Fix displacement Displacement:120(cm3) Expansion
valve
Thermostatic expansion
valve
Saginomiya1.5ton of
refrigeration
Engine Displacement:1.8L Radiator Serpentine600mm·400mm·30mm Oil cooler Tube in tube60mm·80mm·120mm
1180Z.-g.Qi et al./Energy Conversion and Management48(2007)1176–1184
3.Simulation results and discussion 3.1.Experimental validation
In order to validate the accuracy of the vehicle climate control system simulation models,validation experiments were conducted.Fig.4shows the Environmental Simula-tion Laboratory schematic diagram of the validation exper-iments.Some main components’geometries are shown in Table 2.The amount of superheat at the exit of the evapo-rator is set to 5°C,and the subcooling at the exit of the condenser is ?xed at 5°C.The experiments were organized according to the automobile industry standard [19].Fig.5shows the simulation and the experimental condition.The precision of the measured parameters is shown in Table 3.The refrigerant used in the experiments is R-134a.
In order for the proposed system to be satisfactory,the capacity to cool the passenger compartment must be o?ered.In general,the direct measurement of evaporator capacity is very complicated.We often calculate the evap-orator capacity using experimental data.Some errors will be brought into the results.In engineering,the cooling curve is usually used to indicate the satisfactoriness of the system.Fig.6shows the calculational results of the cooling curve compared with the experimental data.During the ?rst 15min,the simulation data have good agreement with the experimental data.After that time,the experimental data is about 2–3°C higher than the calculational data because the ornaments in the passenger compartment have a large heat capacity,which is not re?ected in the simula-tion models,and the temperature change will usually respond in a few minutes.It is well established that this dif-ference of experimental and calculational data is acceptable in engineering.
The compassion between simulation results and experi-mental data of the coolant temperature at the exit of the radiator is shown in Fig.7.It shows that during all the sim-ulation and experimental conditions,the two results are mostly coincident in a wide test range,and the maximum error is about 5%.The two ?gures show that the total sim-ulation model of the vehicle climate control system is avail-able in performance analysis,and the calculational results have an adequate accuracy.
3.2.E?ects of engine cooling system on MAC
The simulation results of the individual MAC and MAC coupled with engine cooling system were compared.Fig.8describes the variability of the evaporator capacity in the two di?erent systems.It shows that the evaporator capacity of the vehicle climate control system is lower than that of the individual MAC system because heat from the
engine
Fig.5.Simulation and experimental conditions.
Table 3
The precision of experimental parameters Items Scale Precision Vehicle speed 0–200(km h à1)±0.1(km h à1)Environmental temperature à30°C to 60°C ±1(°C)
Relative humidity 15–95%±5%
Sunlight power
0–1100(W m à2)The ?uctuation of the temperature
on the top of vehicle is ±3(°C)Air velocity
0–140(km h à1)±0.5(km h à1)Thermocouple (K type)±0.1(°C)Pressure transducer
0–18(bar)
±0.1
(bar)
https://www.sodocs.net/doc/70277691.html,parison of cooling curve vs.test time.
Z.-g.Qi et al./Energy Conversion and Management 48(2007)1176–11841181
compartment is conducted to the passenger compartment through the vehicle body,which increases the heat duty.Fig.9shows the variability of power consumption of the compressor in the two di?erent systems.It presents that compressor power of the vehicle climate control system is greater than that in the individual MAC during the whole simulation period.It is considered that the engine opera-tional status in the engine cooling system in?uences the compressor operation via the viscous clutch.These phe-nomena are particularly obvious during the low speed,gra-dient and idle status.
Fig.10shows the e?ect of the engine cooling system on the coe?cient of performance (COP)of the mobile air con-ditioning system.The engine cooling system results in the COP of the mobile air conditioning system being decreased
clearly during the entire simulation time,especially during the low vehicle speed and idle status.The maximum decrease of COP is up to 10%.It is considered to be due to the decrease of evaporator capacity and the increase of the compressor work simultaneously during a wide opera-tional conditioning range.
The e?ect of vehicle speed on the performance of the mobile air conditioning system is shown Fig.11.When the vehicle speed is changed from 20km/h to 40km/h,the cooling capacity increases up to 13%,and the compres-sor power increases up to 23%at the same time,but the COP of the MAC decreases sharply.It is considered to be due to the fact that the rate of increase in the compres-sor power becomes larger than the rate of increase in the evaporator capacity.The evaporator capacity will keep steady as the vehicle speed is higher than 40km/h.In
other
https://www.sodocs.net/doc/70277691.html,parison of COP (individual MAC and MAC coupled with engine cooling
system).
https://www.sodocs.net/doc/70277691.html,parison of coolant temperature at the exit of radiator vs.test
time.
https://www.sodocs.net/doc/70277691.html,parison of evaporator capacity (individual MAC and MAC coupled with engine cooling
system).
https://www.sodocs.net/doc/70277691.html,parison of compressor power (individual MAC and MAC coupled with engine cooling system).
1182Z.-g.Qi et al./Energy Conversion and Management 48(2007)1176–1184
words,the mobile air conditioning system can maintain a better cooling performance in a wide vehicle speed range.3.3.E?ect of MAC on the engine cooling system
Fig.12shows the comparison of the heat output of the radiator between the vehicle climate control system and the individual MAC.The heat output of the radiator is higher than that of the individual MAC system throughout the whole simulation time.It is the result of the exit air temper-ature of the condenser being higher than the environmental air temperature,which decreases the temperature di?erence
of heat transfer on the air side of the radiator.The maxi-mum di?erence in heat output of the radiator between the two di?erent systems is about 3kW.
Fig.13shows the e?ect of air temperature at the exit of the condenser on the heat output of the radiator at the vehicle speed of 120km/h.It shows that the heat output of the radiator decreases with the increase of the exit air temperature of the condenser.At the worst condition,the heat output of the radiator decreases about 1.5kW.
Fig.14shows the e?ect of air temperature at the exit of the condenser on the temperatures of the coolant,
oil
Fig.11.E?ect of vehicle speed on the performance of air conditioning
system.
https://www.sodocs.net/doc/70277691.html,parison of heat output of radiator (individual MAC and MAC coupled with cooling
system).
Fig.13.E?ect of air temperature at the exit of condenser on the heat output of radiator.
Z.-g.Qi et al./Energy Conversion and Management 48(2007)1176–11841183
and air in the engine cooling system at the vehicle speed of 120km/h.Most temperatures in the engine cooling system will increase with the increase of air temperature at the exit of the condenser.The coolant temperature at the exit of the radiator reaches 102°C when the air tem-perature at the exit of the condenser is higher than the environmental temperature up to 11–14°C,which exceeds the temperature within which the engine can work normally.This condition should be avoided in the design period and improvement process of the mobile air conditioning system and engine cooling system.4.Conclusions
Based on commercial software,a simulation model of the mobile air conditioning system coupled with the engine cooling system is developed.The vehicle climate control system mainly contains a laminated evaporator,a parallel ?ow condenser,a ?xed displacement reciprocat-ing compressor,an externally equalized thermostatic expansion valve,an engine,a serpentine type radiator and a tube in tube oil cooler.The models of the compo-nents are based on great amounts of experimental data.Then,validation experiments are performed at the envi-ronmental simulation laboratory,and the experimental results are compared with the simulation results.The comparative results show that the simulation model of the vehicle climate control system is available in engineer-ing and has a good accuracy.
The following conclusions are drawn from the perfor-mance simulation and analysis of the vehicle climate con-trol system:
1.The engine cooling system a?ects the performance of the mobile air conditioning system considerably.The simu-lation results show the engine cooling system results in the COP of the mobile air conditioning system decreas-ing clearly during the entire simulation time,especially during the low vehicle speed and idle status.The maxi-mum decrease of COP is up to 10%.
2.Changes of heat duty of the mobile air conditioning sys-tem result in high air temperature at the exit of the con-denser,reducing the driving potential for heat transfer from the coolant to air,which induces the heat output of the radiator to decrease sharply.The maximum di?er-ence of heat output of the radiator between the engine cooling systems and the vehicle climate control system is about 3kW.References
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Fig.14.E?ect of air temperature at the exit of condenser on the temperature of coolant,oil and air.
1184Z.-g.Qi et al./Energy Conversion and Management 48(2007)1176–1184
发动机冷却系统设计规范
编号: 冷却系统设计规范 编制：万涛 校对: 审核: 批准: 厦门金龙联合汽车工业有限公司技术中心 年月曰
第2页 一、概述 要使发动机正常工作，必须使其得到适度的冷却，冷却不足或冷却过度均会带来严 重的影响。 发动机过热，会破坏各运动机件原来正常的配合间隙，导致摩擦阻力增 特别是活塞 环和气缸壁之间的运动，严重时会发生烧蚀、卡滞，使发动 “拉缸”现象，刮伤活塞或气缸，更严重时还会发生连杆打烂气缸体现 油变稀，运动机件间的油膜破坏，造成干摩擦或半干摩擦，加速磨损。 同时会降低发动 机充气量，使发动机功率下降。 发动机过度冷却时，由于冷却水带走太多热量，使发动机功率下降、动力性能变差。 发动机过冷，气缸磨损加剧。同时，由于过冷，混合气形成的液体，容易进入曲轴箱使 润 滑油变稀，影响润滑作用。 由此可见，使发 动机工作温度保持在最适宜范围内的冷却系，是何其重要。一般地, 发动机最适宜的工作温度是其气缸盖处冷却水温度保持在 80C ~90C ,此时发动机的动力 性、经济性最好。 、冷却系统设计的总体要求 a ）具有足够的冷却能力，保证在所有工况下发动机出水温度低于所要求的许用值（ 般为55°); 冷却系统的设计应保证散热器上水室的温度不超过99 Co 采用105 kPa 压力盖，在不连续工况运行下，最高水温允许到 110 C,但一年中 水温达到和 超过99 C 的时间不应超 过50 ho 冷却液的膨胀容积应等于整个系统冷却液容量的 6 %o 冷却系统必须用 不低于19 L/min 的速度加注冷却液，直至达到应有的冷却液平面, 以保证 所有工作条件下气缸体水套内冷却液能保持正常的压力。 三、冷却系统的构成 液体冷却系主要由以下部件组成：散热器、风扇、风扇护风罩、皮带轮、风扇离合器、 水泵、节温器、副水箱、发动机进水管、发动机出水管、散热器除气管、发动机除气管冷却不足, 加，磨损加剧, 机停转或者发生 象。也会使润滑 a) C ） d) e)
船舶冷却水系统设计指导
编制大纲： 需要补充的内容：1，水泵（定速离心泵，变频泵）；2，温控阀；3，节流孔板；4，热平衡计算的理论公式，温升热量水量公式；5，特殊案例的区分（温控阀，板冷，变频泵对整个冷却系统形式选定的影响；分离封闭式，高低温混流式，配置变频海水泵没有温控阀的中央式。）6，利用目前的实船进行计算公式的验证，还有一些经验系数的反推导（特别是一些厂家自己的经验系数）7，膨胀水箱；8，补充开发设计需要的部分，参考《船舶管舾装设计工艺实用手册》 前言（目的） 以《船舶设计实用手册---轮机分册》---国防工业出版社为蓝本，将其中的冷却水系统做了进一步内容扩展和深化描述，提供给详细设计人员参考。 参考《船舶管舾装设计工艺实用手册》，补充一部分工程计算公式； 系统发展核心： 1，稳定调节； 2，节省能源，余热循环利用； 3，节省成本，替代方案的方式； 关键词： 将冷却水稳定可靠的输送到需要冷却的设备中：这个可靠和稳定来源于几个参数：稳定的压力，稳定的流量，稳定的温度，稳定的水质（这个水质包含化学成分稳定不结垢，物理成分稳定，极少气泡，气泡会影响热交换器的效率）
冷却水系统 目录 1，范围 2，冷却水系统的基本形式 3，系统形式的选择 4，冷却水系统实例 5，中央冷却系统热平衡计算 6，冷却水系统的主要设备配置要点 7，制淡装置（造水机） 8，具有冰区航行船级符号船舶的冷却水系统特殊要求9，海水进水阀操纵位置的要求 10，冷却水系统的温控阀 11，冷却水系统的节流孔板 12，冷却水系统的泵 13，冷却水系统的膨胀水箱
冷却水系统 1，冷却水系统的基本形式 冷却水系统的基本形式见表1， 注解： （1），所谓开式和闭式冷却水系统是指柴油机本身冷却水系统而言。开式系统是指柴油机本身直接用舷外海水或者江水冷却。如今除江河小船之外，基本不采用开式系统。海拖（海洋港口拖轮）还在使用海水直接冷却柴油机。（潜在问题：船内海水泄露，在与柴油机连接的弹性管配置不正确时容易出现，已有其他公司的海拖因为这个弹性管破裂造成沉船）
船舶发动机冷却系统
第六章冷却系统 第一节冷却系统的功用、组成和布置 一、冷却系统的功用 柴油机工作时的燃气温度高达1800℃左右，使与燃气直接接触的气缸盖、气缸套、活塞、气阀、喷油器等部件严重受热。严重的受热会造成： ①材料的机械性能下降，产生较大的热应力与变形，导致上述部件产生疲劳裂纹或塑性变形； ②破坏运动部件之间的正常间隙，引起过度磨损，甚至发生相互咬死或损坏事故； ③燃烧室周围部件温度过高，使进气温度升高，密度降低，从而减少进气量；增压 后的空气温度也会升高，并影响进气量； ④润滑油的温度也逐渐升高，粘度下降，不利于摩擦表面油膜的形成，甚至失去润 滑作用。 综上所述，为了保证柴油机可靠工作必须对柴油机受热机件，滑油及增压后的空气等进行冷却。 然而从能量利用观点来看，柴油机的冷却是一种能量损失，过分冷却将导致燃油滞燃期延长，产生爆燃和燃烧不完全，增加加散热损失；机件内外温度差过大，以致热应力超过材料本身的强度而产生裂纹，润滑油粘度变大而增加摩擦功的消耗；在燃用含硫量较高的重油时，将产生低温腐蚀，使缸套严重腐蚀等。 因此，在管理中应既不使柴油机因缺乏冷却而导致机件过热，也不使柴油机因过分冷却而造成不良后果，应有所兼顾。冷却系统的主要任务应是保证柴油机在最适宜的温度状态下工作，达到既能避免零件的损坏和减小其磨损，又能充分发出它的有效功率。近代，从尽量减少冷却损失以充分利用燃烧能量出发，国内、外正在进行绝热发动机的研究，相应发展了一批耐高温的受热部件材料，如陶瓷材料等。 目前，柴油机的冷却方式分为强制液体冷却和风冷两种，绝大多数柴油机使用前者。 而液体冷却的介质通常有淡水、海水、滑油等三种。 淡水的水质稳定，传热效果好并可采用水处理解决其腐蚀和结垢的缺陷，因而它是目前使用最广泛的一种理想冷却介质； 海水的水源充裕但水质难以控制且其腐蚀和结垢问题比较突出，为减少腐蚀和结垢应限制海水的出口温度不应超过55℃； 滑油的比热小，传热效果较差，在高温状态易在冷却腔内产生结焦，但它不存在因漏泄而污染曲轴箱油的危险，因而适于作为活塞的冷却介质。 二、冷却系统的组成和布置 柴油机冷却系统一般是用海水强制冷却淡水和其它载热流体（如滑油、增压空气等）。在系统布置上，海水系统属开式循环，淡水及滑油等属于闭式循环，两者组成的冷却系统称“闭式冷却系统”。 （一）开式循环冷却系统
船用柴油机冷却水系统处理
船用柴油机冷却水系统处理 摘要船用柴油机是船舶心脏，在航行过程中有着举足轻重的作用，为使柴油机在合适的温度下能够安全有效的工作，对于冷却水系统就显得尤为重要，本文结合日常工作实际，对船用柴油机冷却水系统在检修、清洗及防腐步骤进行论述，使从事柴油机工作人员在进行柴油机的日常维护有所启迪。 关键词船用柴油机；冷却水系统；检查 0引言 柴油机冷却系统的主要功能是用来控制发动机的工作温度和驱散多余的热能（含润滑系统的散热）。系统好坏对发动机的工作和使用寿命有着直接的关系。因此，日常检查和清洗及防腐就显得尤为重要。在船舶柴油机使用过程中，由于缺乏对冷却系统的科学认识，不能正确检查和对冷却水及时去做防腐，甚至误认为冷却水温越低越好，影响了冷却系统的正常功能，造成了柴油机运行不稳定，使其使用寿命大大降低。 1冷却水系统 1.1冷却水系统的防腐保护 柴油机冷却水必须仔细处理，保存和检测，以避免腐蚀或形成沉淀，从而使热传热效率降低。因此很有必要对冷却水进行处理。应按如下步骤进行处理：1）清洗冷却水系统；2）注满带防腐剂的无离子水或蒸馏水（来自淡水发生器的水）；3）对冷却水系统和冷却水状况进行定期检查。遵守这些预防规定，确保系统排泄良好，就会使由冷却水引起的故障降至最低。 1.2冷却水系统的清洁处理 1）在防腐处理之前，必须除去系统中的石灰沉淀层，铁锈和油泥，以改善热传导和确保防腐剂对表面进行保护的均匀性； 2）清洁处理应包括除油泥，酸洗除锈和清除水垢； 3）水乳化清洁剂和弱碱性清洁剂一样可以用于除油污过程； 4）不得使用含有易燃物的预混合清洁剂。用酸除锈时，推荐采用以氨基硫酸，柠檬酸，酒石酸为基础的专门产品，这些酸通常固态易溶于水且不会散发出有毒的蒸汽； 5）清洁剂不应直接混合，而应溶于水后再加入到冷却水系统中； 6）清洗时一般不必拆卸柴油机零件，水在柴油机中循环才能达到最佳的效果； 7）清洁可使不良配合的结合处或有缺陷的垫片部位渗漏更明显，因此在净化过程中应进行检查。在清洁后的24小时要检查滑油系统的含酸量。 1.3未净化的水 1）建议使用无离子水或蒸馏水（如由淡水发生器产生水）作为冷却水。由于硬度较低，这种水还具有相当的腐蚀性，应不断加入防腐剂； 2）如果没有无离子水或蒸馏水，特殊情况下可使用饮用水。但是水的总硬度不得超过9°DH。要检查水中的氯化物，氯，硫酸盐，硅酸盐的含量。它们不能超过下列值：氯化物：50ppm（50mg/L）；氯：10ppm（10mg/L）；硫酸盐：100ppm （100mg/L）；硅酸盐：150ppm（150mg/L）； 3）水中不得含有硫化物和氨。绝对不能使用雨水，因为雨水可能已被严重污染。应该注意的事，对水的软化处理不会降低硫酸盐和硅酸盐的含量。
新能源汽车空调系统技术初探
新能源汽车空调系统技术初探摘要：随着新能源汽车产业深入推进，不仅推动了空调系统技术发展步伐，并且使用效益更加显著。新能源汽车应用的空调系统主要包括余热利用空调与热泵式空调系统两种，无论是在压缩机类型上，还是在制冷制热系统形式上，以及蒸发器、冷凝器等方面，都存在较大差异。但对空调系统安全性、可靠性等方面的追求都是不变的，以确保驾驶室舒适度与稳定性。 关键词：新能源汽车；空调系统；热泵 新能源汽车项目起步晚，且发展处于摸索实践阶段，整车结构及系统仍有较大的完善空间。尤其是空调技术发展仍面临着电池造价高、设计工艺水平低、电池过热，以及内部零件碰撞等问题，尤其是在高速行驶中，以此对空调装置结构与系统性能提出了更高的要求。空调系统技术的发展势必会带动项目产业化发展，但目前首要的是攻克电池瓶颈，加大燃料电池，以及电动压缩机研发力度，利用新型环保制冷，能够进一步推动汽车工业改革。 1新能源车空调系统分析 1.1燃料电池余热利用空调系统 燃料电池发电装置能够将化学能有效转换为电能，借助燃料与氧化剂实现，转化效率高，其余转化为废热与温水、蒸汽。燃料电池属于动力源，利用能源效率比常规内燃机高，但燃料电池出现过热后，其性能、工作效率直接降低。对此，利用余热为车辆供暖，其经济性、能量利用率明显优化。综合考虑能源供应与性价比、生态环保等因素，
研究结果表明氢是首选燃料。电解质种类多样，可分为熔融碳酸盐类，以及固体氧化物类等，其中质子交换膜燃料电池，工作电流相对较大，能量效率高，且可在数秒时间内完成冷启动，排出近80℃的废热，多以吸收式制冷空调系统为主，热泵启动热源，以燃料电池冷却液为主。对此，吸收式热泵发动机输出功率消耗低，熔液泵需消耗部分电能。同时吸收式热泵，其总需求电能相比压缩式热泵高。为满足城市公交与大巴空调制冷需求，加强了对吸收式制冷系统的创新，制冷剂以乙二醇和水为主，吸收剂以溴化锂为主，吸收式制冷系统热动力驱动，主要通过热管理系统主管热器，与制冷系统发生器的热交换实现。主换热器上设置旁通支路，并连接变频水泵，当燃料电池热量过高，且由空调制冷需求时，热量能从旁通支路给予，确保燃料电池始终保持适宜温度工况。同时电池辅助器与吸收器等电池热管理系统器件的冷却系统相同，车外风冷式换热器与冷却系统相通。燃料电池供暖系统的工作过程如下，截止阀打开后，使电池发动机处于工作状态，控制电池散热器，通过中间换热器，实现冷却液从发动机出口处流至进口处，由换热器热能沿着供暖管路持续向车内提供热风。 1.2热泵式空调系统 热泵式压缩机是由独立式电机驱动，动力系统驱动电机，以及电动压缩机是由电池组供电，不会影响汽车运行安全性，同时也不会受到汽车运行的干扰。热泵式空调系统应用后，从车内顶部吸入新鲜空气，空气加热后，在挡风玻璃内完成除霜处理，并吹出热气，即在内部处理后由风道左右两侧吹出。不仅节省能耗，同时解决了车内湿度
发动机冷却系统设计规范..
发动机冷却系统设计规范..
号： 冷却系统设计规范 编制：万涛 校对： 审核： 批准： 第1页
第1页
水泵、节温器、副水箱、发动机进水管、发动机出水管、散热器除气管、发动机除气管等。 四、主要部件的设计选型 1、散热器 散热器的散热量（Q）和散热器散热系数（K）、散热器散热面积（A）及气液温差（⊿T）有关： Q=K·A·⊿T 其中：Q---散热器的散热量（kcal/h） K---散热器散热系数（kcal/m2?h?oC） A---散热器散热面积（m2） ⊿T---气液温差：散热器进水温度和散热器进风温度之差（oC）散热器的散热系数是代表散热效率的重要指标，主要影响因素如下： ①冷却管内冷却液的流速---据试验结果，冷却液流速由0.2m/s提高到0.8m/s，散热效 率有较大提高，但超过0.8m/s后，效果不大； ②通过散热器芯部的空气流量---空气的导热系数很小，因此散热器的散热能力主要取决 于空气的流动，通过散热器芯部的风量起了决定性作用； ③散热器的材料和管带的厚度---国内散热器的材料目前基本上已标准化； ④制造质量---主要是冷却管和散热带之间的贴合性和焊接质量； 第1页
1.1 散热器是冷却系统中的重要部件，其主要作用是对发动机进行强制冷却，以保证发动机能始终处于最适宜的温度状态下工作，以获得最高的动力性、经济性和可靠性。 1.2 发动机最适宜的冷却液温度为85 ℃~95 ℃，测量位置在散热器的上水室。 1.3 散热器和风扇组合匹配效率是当散热器芯子未被气流扫过的面积最小时为最高，因此，最好采用接近正方形的散热器芯子。 1.4 散热器的总散热面积、芯子的迎风面积、结构形状和结构尺寸要通过发动机冷却系统所需最大散热量来计算确定，并应通过试验评价来最终确定。但一般可按散热器芯子的迎风面积来估算：0.31~0.38m2/100kW，载货车和前置客车通风良好时，可取下限值；后置客车通风欠佳时可取上限值；城市公交车长期低速运转可偏下限值；自卸车、牵引车、山区长途客运车等经常大负荷运行的车辆可偏上限值。 1.5 散热器进风口的实际面积不得小于散热器芯子迎风面积的80 %，以防止散热能力下降。后置客车散热器的进风通道要与发动机舱密封隔离，散热器周围要安装密封橡胶，以防止发动机舱的热风回流到进风通道，影响散热性能；进风通道的面积应不小于散热器芯子的迎风面积。 1.6 在灰尘多的脏环境下使用时，应选用直排或斜排冷却管，且管子间隔要大，以避免散热器芯子堵塞，影响散热效果。 1.7 散热器安装时，紧固必须牢靠，与车架的连接必须采用减振垫，采用减振垫的目的是为了隔离和吸收来自车架的部份振动和冲击，使散热器在车辆运行中，不致发生振裂、扭曲等非正常损坏，延长散热器寿命。 1.8 因为散热器与车架之间安装有隔振橡胶，因而形成了绝缘状态，通过冷却液介质，在散热器与车架之间产生了电位差，在冷却液中产生了微弱电流，使冷却系统的零部件发生电腐蚀。因此，一定要采取散热器负极接地等措施，消除电位差，防止电腐蚀。 2 冷却风扇 风扇选型主要考虑风扇的风量、噪声和功率消耗。 风扇风量（G）与风扇直径（D）、风扇转速（n）之间存在如下比例关系： G=K1?n?D3------其中K1为比例系数 而风扇噪声的声压级（SPL）和风扇直径（D）、风扇转速（n）之间存在如下比例关系： SPL= K2?n3?D2------其中K2为比例系数 根据上述比例关系可得：SPL= K3?Q?n2/D------其中K3为比例系数 第2页
柴油发动机冷却系统使用与维护研究
柴油发动机冷却系统使用与维护研究 摘要对于柴油机而言，正确使用、合理维护冷却系统可使其性能得到有效提升。然而，在日常使用过程中，仍有大量关于冷却系统的错误认识存在，以至于柴油机性能受到影响。基于此，本文入手于柴油机冷却系统的组成及功用，并在此基础上探讨使用、维护方法。 关键词柴油发动机；冷却系统；使用与维护 柴油发动机零部件在吸收燃烧气体后，会有热量产生，冷却系统主要便是将这些热量及时散发，为发动机的工作提供适宜的温度环境，对发动机零部件温度进行有效控制，为其使用寿命提供保障，为发动机使用功率的充分发挥奠定基础。因此，本文主要对柴油发动机冷却系统适用于维护展开研究。 1 冷却系统的组成及功用 以散热方式为根据对柴油机冷却系统进行分类，主要包含水冷却和空气冷却系统。水冷却系统的组成成分有水泵、配水管、散热器、风扇、调温器和水温表等。该系统主要负责将柴油机运作过程中零部件所接收的热量朝着大气及时散发，以正常范围控制柴油机工作温度。发动机工作时，冷却水会在水泵的作用下由配水管传输至缸盖、水套，而吸收了热量则会朝着散热器上部传输，途经散热器芯传输至散热器下部。同时，当热量传到散热器芯、片时，空气会在风扇的旋转下朝着散热器流动，加快热量散发，实现水温降低。水在经过冷却后，在水泵的作用下再次进入水套，不断循环。 2 冷却系统的使用与维护 2.1 水泵的使用与维护 水泵使用过程中，难免会有故障发生，故而必须重视水泵的正确使用及合理维护措施。 首先，在水泵使用过程中，水泵若是带有齿轮传动，那么水泵齿轮、传动齿轮之间的啮合必须保持良好；水泵若是带有皮带传动，那么水泵皮带与传动皮带轮槽必须同线，其松紧度也需维持在适宜的程度[1]。松紧度过紧会使水泵轴承承受更大的负荷，缩短轴承的寿命。而松紧度过松会有皮带打滑的现象出现，以至于降低水泵工作效率。 水泵使用中，需定期开展保养工作，以列举于说明书内的要求为根据，将润滑油及时加注至水泵轴承内，在加注时必须合理控制加注量，以免水泵轴承使用寿命缩短。同时，针对水泵工作状态定期开展检查工作，在水泵传动皮带拆除后应能自如地用手转动皮带轮，水泵叶轮、泵壳之间不会发生擦碰，泵轴内不会存在卡滞。要想确保发动机的运转正常，就必须正确使用、合理维护水泵，为其提
柴油机冷却水系统处理
柴油机冷却水系统处理 【摘要】柴油机是柴油车的心脏，在车辆行驶过程中有相当重要的作用，为使柴油机在合适的温度下能够安全有效的工作，对于冷却水系统就显得格外重要。本文对柴油机冷却水在检修、清洗及防腐步骤进行论述。 【关键词】柴油机冷却水系统清洗防腐 柴油机冷却系统的主要功能是用来控制发动机的工作、温度和驱散多余的热能（含润滑系统的散热），系统的好坏对发动机的工作和使用寿命有直接关系，因此，日常检查和清洗及防腐就显得尤为重要。 1 冷却水系统的防腐保护 冷却水必须仔细处理、保存和检测，以避免腐蚀或形成沉淀，从而使热传导效率降低。因此要进行对冷却水处理。 1.1 处理步骤 （1）清理冷却水系统。（2）注满带防腐剂的无离子水或蒸馏水。（3）对冷却水系统和状况进行定期检查。遵守以上规定，会使冷却水引起的故障降至最低。 1.2 冷却水系统的清洁处理 （1）在防腐处理前，必须除去系统中的石灰沉淀层、铁锈和油泥，以改善热传导和确保防腐剂对表面进行保护的均匀性。（2）清洁处理应包括油泥酸洗除锈和清洗水垢。（3）水乳清洁剂和弱碱性清洁剂一样可以用于除油污过程。（4）不得使用含有易燃物的预混合清洁剂，通常采用氨基酸、柠檬酸、酒石酸为主，这些易溶于水，不会散发有害蒸汽，清洁剂不直接使用，要溶于水后再加入系统中。（5）清洗时不必拆卸发动机零件，水在发动机循环才能达到最佳效果。（6）清洁可使不良配合的结合处或有缺陷的垫片部位渗漏更明显，因此在净化过程中应进行检查，在清洁后的24小时要检查润滑系统的含酸量（机油）。 2 未净化的水 （1）建议使用无离子水或蒸馏水作为冷却水，由于硬度较低，这种冷却水还具有相当的腐蚀性p （1）加满清洁的自来水，原有的水可以放掉，将水加热到60℃在发动机中连续循环，按规定剂量加入除油化学剂在规定周期循环清洁化学制剂。（2）冷却水系统必须在无压力状态下检查并排除任何泄露，放掉系统中的水再加满清洁的自来水，将水循环两小时后放掉。 4.2 酸洗除锈
发动机冷却系统总体参数设计
一、冷却系统说明 二、散热器总成参数设计 三、膨胀箱总成参数设计 四、冷却风扇总成参数设计 五、水泵总成参数设计 六、橡胶水管参数设计 七、节温器选择 八、冷却液选择 一、冷却系统说明 内燃机运转时，与高温燃气相接触的零件受到强烈的加热，如不加以适当的冷却，会使内燃机过热，充气系数下降，燃烧不正常（爆燃、早燃等），机油变质和烧损，零件的摩擦和磨损加剧，引起内燃机的动力性、经济性、可靠性和耐久性全面恶化。但是，如果冷却过强，汽油机混合气形成不良，机油被燃烧稀释，柴油机工作粗爆，散热损失和摩擦损失增加，零件的磨损加剧，也会使内燃机工作变坏。因此，冷却系统的主要任务是保证内燃机在最适宜的温度状态下工作。 1.1 发动机的工况及对冷却系统的要求 一个良好的冷却系统，应满足下列各项要求： 1）散热能力能满足内燃机在各种工况下运转时的需要。当工况和环境条件变化时，仍能保证内燃机可靠地工作和维持 最佳的冷却水温度；
2）应在短时间内，排除系统的压力； 3）应考虑膨胀空间，一般其容积占总容积的4-6%； 4）具有较高的加水速率。初次加注量能达到系统容积的90%以上。 5）在发动机高速运转，系统压力盖打开时，水泵进口应为正压； 6）有一定的缺水工作能力，缺水量大于第一次未加满冷却液的容积； 7）设置水温报警装置； 8）密封好，不得漏气、漏水； 9）冷却系统消耗功率小。启动后，能在短时间内达到正常工作温度。 10）使用可靠，寿命长，制造成本低。 1.2 冷却系统的总体布置 冷却系统总布置主要考虑两方面：一是空气流通系统；二是冷却液循环系统。在设计中必须作到提高进风系数和冷却液循环中的散热能力。 提高通风系数：总的进风口有效面积和散热器正面积之比≥30%。对于空气流通不顺的结构，需要加导风装置使风能有效的吹到散热器的正面积上，提高散热器的利用率。 在整车空间布置允许的条件下，尽量增大散热器的迎风面积，减薄芯子厚度。这样可充分利用风扇的风量和车的迎面风，提高散热器的散热效率。一般货车芯厚不超过四排水管，轿车芯厚不超过二排水
柴油机冷却水系统
30. 冷却水系统 说明 冷却水系统…………………………………………………………第30-191页 工作卡 30 101-01冷却水恒温阀…………………………………………第30-193页 30 102-02冷却水泵的检修和更换………………………………第30-195页 备件图页 高温冷却水泵,顺时针方向……………………………………….图页号1 3010 高温冷却水泵,逆时针方向……………………………………….图页号1 3010 低温循环系统的冷却水恒温阀 手动越控………………………………………………………图页号1 3012 高温循环系统的冷却水恒温阀 手动越控………………………………………………………图页号1 3012 高温冷却水管……………………………………………………..图页号1 3016 发布号TOC_1 30 第30-189页
第30-190页 发布号TOC_1 30
冷却水系统 本柴油机只设计为淡水冷却，因此冷却水系统必须是中央/闭式冷却系统。 本柴油机设计几乎是无管子的，即水在前端 箱和气缸组件内部的水腔、水道中流动。所有大的管接头均设在前端箱中。在柴油机后端，供应齿轮箱滑油冷却器的淡水应由船厂连接上。 发布号1 30 A1-01 第30-191页
本柴油机的高、低温冷却水系统配有机带Array 高、低温淡水泵。为加强备用泵的自动启动功能，系统内设置了双作用式止回阀。 淡水泵安装在柴油机前端箱中，由曲轴通过齿轮系驱动。 泵的轴承由柴油机的滑油系统供油自动进行润滑。 控制高、低温冷却水系统的恒温元件也置于前端箱中。 增压空气冷却器分为二级，第一级由高温冷却水系统进行冷却，从增压器出来的高温空气传给冷却水的热量有可能较多地回收。第二级由低温冷却水系统进行冷却，使进入柴油机的空气温度得到进一步的降低。 在北极高寒地区航行时，直接从甲板进入的空气温度低，可采用一种调节系统来控制空气冷却器的第二级冷却水流量，以提高低负 荷下的增压空气温度。
船用柴油机主要系统介绍-燃油-滑油-冷却
第五章柴油机系统 第一节燃油系统 一、作用和组成 燃油系统是柴油机重要的动力系统之一，其作用是把符合使用要求的燃油畅通无阻地输送到喷油泵入口端。该系统通常由五个基本环节组成：加装和测量、贮存、驳运、净化处理、供给。 燃油的加装是通过船上甲板两舷装设的燃油注入法兰接头进行的。这样，从两舷均可将轻、重燃油直接注入油舱。注入管应有防止超压设施。如安全阀作为防止超压设备，则该阀的溢油应排至溢油舱或其他安全处所。注入接头必须高出甲板平面，并加盖板密封，以防风浪天甲板上浪时海水灌入油舱。燃油的测量可以通过各燃油舱柜的测量孔进行，若燃油舱柜装有测深仪表的话，也可以通过测深仪表,然后对照舱容表进行。 加装的燃油贮存在燃油舱柜中。对于重油舱，一般还装设加热盘管，以加热重油，保持其流动性，便于驳油。 燃油系统中还装设有调驳阀箱和驳运泵，用于各油舱柜间驳油。 从油舱柜中驳出的燃油在进机使用前必须经过净化系统净化。燃油净化系统包括燃油的加热、沉淀、过滤和离心分离。图5-1示出了目前大多数船舶使用的重质燃油净化系统。 图5-1 重质燃油净化系统 1-调驳阀箱；2-沉淀油柜燃油进口；3-高位报警；3-低位报警；4-温度传感器；5-沉淀油柜；6、16-水位传感器；7-供油泵； 8-滤器；9-气动恒压阀；9’-流量调节器；10-温度控制器；11、12-分油机；13-连接管；14-日用柜溢油管；15-日用油柜从图可以看出，通过调驳阀箱1，燃油被驳运泵从油舱送入沉淀油柜5，每次补油量限制在液位传感器3与3之间，自动调节蒸汽流量的加温系统加速油的沉淀分离并且可使沉淀油柜
提供给供油泵7的油温变化幅度很小。供油泵后设气动恒压阀9和流量控制阀9’，以确保平稳地向分油机输送燃油，有利于提高净化质量。燃油进入分油机前，通过分油机加热器加温，加热温度由温度控制器10控制，使进入分油机的燃油温度几乎保持恒定。系统设有既能与主分油机串联也能并联的备用分油机，还设有备用供油泵，提高了系统的可靠性。分油机所分的净油进入日用油柜15，日用油柜设溢流管。在船舶正常航行的情况下，分油机的分油量将比柴油机的消耗量大一些，故在吸入口接近日用油柜低部设有溢流管，可使日用油柜低部温度较低、杂质和水含量较多的燃油引回沉淀柜，既实现循环分离提高分离效果，又使分油机起停次数减少，延长分油机使用寿命。沉淀柜和日用柜都设有水位传感器6、16，以提醒及时放残。 燃油经净化后，便可通过燃油供给系统送给船舶柴油机。近年来由于高粘度劣质燃油的使用，其预热温度大大提高。为避免在使用高（700mm2/s）重油时因预热温度过高而汽化，出现了一种加压式燃油系统。如图5-2所示，在日用燃油柜与燃油循环油路之间增设一台输送泵，保证柴油机喷油泵进口处的燃油压力为800kPa（循环泵出口压力为1Mpa），循环油路（回路）中压力为400kPa，防止燃油系统在高预热温度（如150℃）时发生汽化和空泡现象。 图5-2 加压式燃油供给系统 二、主要设备与作用 1．重油驳运泵 重油驳运泵的作用是将任一重油舱中的重油驳至重油沉淀柜中进行沉淀澄清处理；在各
发动机冷却系统设计规范
编号：
冷却系统设计规范
编制： 万 涛
校对： 审核： 批准：
厦门金龙联合汽车工业有限公司技术中心 年月日
一、概述 要使发动机正常工作，必须使其得到适度的冷却，冷却不足或冷却过度均会带来严重
的影响。 冷却不足，发动机过热，会破坏各运动机件原来正常的配合间隙，导致摩擦阻力增加，
磨损加剧，特别是活塞环和气缸壁之间的运动，严重时会发生烧蚀、卡滞，使发动机停转 或者发生“拉缸”现象，刮伤活塞或气缸，更严重时还会发生连杆打烂气缸体现象。也会 使润滑油变稀，运动机件间的油膜破坏，造成干摩擦或半干摩擦，加速磨损。同时会降低 发动机充气量，使发动机功率下降。
发动机过度冷却时，由于冷却水带走太多热量，使发动机功率下降、动力性能变差。 发动机过冷，气缸磨损加剧。同时，由于过冷，混合气形成的液体，容易进入曲轴箱使润 滑油变稀，影响润滑作用。
由此可见，使发动机工作温度保持在最适宜范围内的冷却系，是何其重要。一般地， 发动机最适宜的工作温度是其气缸盖处冷却水温度保持在 80℃~90℃，此时发动机的动力 性、经济性最好。 二、冷却系统设计的总体要求
a)具有足够的冷却能力，保证在所有工况下发动机出水温度低于所要求的许用值（一 般为 55°）； b) 冷却系统的设计应保证散热器上水室的温度不超过 99 ℃。 c) 采用 105 kPa 压力盖，在不连续工况运行下，最高水温允许到 110 ℃，但一年中
水温达到和超过 99 ℃的时间不应超过 50 h。 d) 冷却液的膨胀容积应等于整个系统冷却液容量的 6 %。 e) 冷却系统必须用不低于 19 L/min 的速度加注冷却液，直至达到应有的冷却液平面，
以保证所有工作条件下气缸体水套内冷却液能保持正常的压力。 三、冷却系统的构成
液体冷却系主要由以下部件组成：散热器、风扇、风扇护风罩、皮带轮、风扇离合器、 水泵、节温器、副水箱、发动机进水管、发动机出水管、散热器除气管、发动机除气管等。
汽车发动机冷却系统的设计原则
发动机冷却系统的设计原则 （李勇） 水冷式汽车发动机冷却系统一般由散热器、节温器、水泵、缸体水道、缸盖水道、风扇及连接水管、冷却液等组成。我们主机厂主要根据整车布置及发动机功率的要求来选定散热器及各零部件的形状、大小，并合理布置整个冷却系统，保证发动机的动力性、经济性、可靠性和耐久性，从而提高整车的性能。 一、冷却系统的总体布置原则 冷却系统总布置主要考虑两方面，一是空气流通系统；二是冷却液循环系统。因此在设计中必须做到提高进风系数和冷却液循环中的散热能力。 1，提高进风系数。要做到提高进风系数就必须要做到：（1）减小空气的流通阻力，（2）降低进风温度，防止热风回流。 （1）减小空气的流通阻力 设计中应尽量减少散热器前面的障碍物，进风口的有效进风面积不要小于60﹪的散热器芯部正面积；在整车布置允许的前提下，尽可能采用迎风正面积较大的散热器；风扇与任何部件的距离不应小于20mm，这样就可以组织气流通畅排出，可以减少风扇后的排风背压。 （2）降低进风温度， 要合理布置散热器的进风口，提高散热器与车身、发动机舱接合处的密封性，防止热风回流。 （3）合理布置风扇与散热器芯部的相对位置 从正面看，尽量使风扇中心与散热器中心重合，并使风扇直径与正
方形一边相等，这样可以使通过散热器的气流分布最为均匀，或者使风扇中心高一下些，使空气流经散热器上部的高温高效区。 另：考虑发动机振动的因素，风扇和护风罩之间的间隙应该在20mm 以上。 从轴向看，尽可能加大风扇前端面与散热器之间的距离，并合理设计护风罩。要使气流均匀通过散热器芯部整个面积，必须要求风扇与散热器之间保持一定的距离，一般对载货汽车，风扇与散热器芯部之间的距离不得小于50mm。 2，提高冷却液循环中的散热能力 要提高冷却液循环中的散热能力，提高冷却液循环中的除气能力是关键。冷却系统的气体会造成水泵流量下降，使散热器的冷却率下降；还会造成发动机水套内局部沸腾，致使局部热应力猛增，影响发动机性能；在热机停工况，气体还会造成冷却液过多的损失。因此要提高冷却液循环中的除气能力，其措施就是设计膨胀水箱和相应的除气管路（当散热器位置比发动机位置高时，可以在散热器上部直接开一个注水口，并在注水口上用一压力式的散热器盖即可，我厂的农用车型的散热器就是采用此方式进行排气及加水）。 二、散热器的选择 （1）现在我厂基本上全部都采用铜制散热器，芯部结构为管带式的。散热器要带走的热量Q w，按照热平衡的试验数据或经验公式计算：Q w=（A·g e·Ne·h n）/3600 kJ/s 式中： A—传给冷却系统的热量占燃料热能的百分比，对柴油机A=0.18～0.25
柴油机空调系统和冷却系统的关系
Analysis and simulation of mobile air conditioning system coupled with engine cooling system Zhao-gang Qi *,Jiang-ping Chen,Zhi-jiu Chen Institute of Refrigeration and Cryogenics,School of Mechanical Engineering,Shanghai Jiao Tong University, No.1954,Huashan Road,Shanghai 200030,PR China Received 19September 2005;received in revised form 28March 2006;accepted 8October 2006 Available online 6December 2006 Abstract Many components of the mobile air conditioning system and engine cooling system are closely interrelated and make up the vehicle climate control system.In the present paper,a vehicle climate control system model including air conditioning system and engine cooling system has been proposed under di?erent operational conditions.All the components have been modeled on the basis of experimental data.Based on the commercial software,a computer simulation procedure of the vehicle climate control system has been developed.The performance of the vehicle climate control system is simulated,and the calculational data have good agreement with experimental data.Furthermore,the vehicle climate control simulation results have been compared with an individual air conditioning system and engine cooling system.The in?uences between the mobile air conditioning system and the engine cooling system are discussed.ó2006Elsevier Ltd.All rights reserved. Keywords:Air conditioning system;Engine cooling system;Coupled analysis;Simulation;Comparison 1.Introduction A mobile air conditioning (MAC)system can supply drivers and passengers a safe and comfortable environ-ment.Perfect performance of the MAC is the target that automobile manufacturers pursue in the period of design and development.It is known very well that MAC can sup-ply cold capacity under summer operational conditions and waste heat of the engine is used to heat the passenger com-partment under winter operational conditions.For envi-ronmental factors,researches have been performed extensively to develop and improve the e?ciencies of MAC and engine cooling systems.Heat exchangers are the research emphasis of MAC and engine cooling systems.A lot of correlations,experiments and models about vari-ous heat exchangers have been proposed.Chang and Wang [1,2]and Chang et al.[3]developed thermal characteristics correlations related to the geometrical parameters of heat exchangers with louvered ?ns.Their correlations have good agreement with their and previous experimental data in a wide range of Reynolds numbers based on louver pitch.Nowadays,many advanced technologies have been applied to enhance the performance of the heat exchangers of MAC and engine cooling systems.For engineers and researchers,the simulation procedure [4]of MAC and engine cooling systems can save test cost and manpower considerably.Raman Ali [5]developed a computer pro-gram for the MAC refrigerant circuit.The MAC included a condenser and an evaporator cooled by fans,a ?xed power reciprocating compressor and a thermostatic expan-sion valve.The heat transfer processes of the condenser and evaporator were divided into three parts as liquid,two phase and gas phase.All the nonlinear algebraic equa-tions were solved by iterative procedures.Saiz Jabardo et al.[6]proposed a steady computer program for an auto-mobile air conditioning system.The authors implied that operational parameters such as compressor speed,return air temperature in the evaporator and condensing air tem-peratures have an obvious e?ect on the performance of a 0196-8904/$-see front matter ó2006Elsevier Ltd.All rights reserved.doi:10.1016/j.enconman.2006.10.005 * Corresponding author.Tel.:+862162933242;fax:+862162632601.E-mail address:qizhaogang@https://www.sodocs.net/doc/70277691.html, (Z.-g.Qi). https://www.sodocs.net/doc/70277691.html,/locate/enconman Energy Conversion and Management 48(2007) 1176–1184
柴油机的冷却系统1
柴油机的冷却系统 一、冷却系统的方式 冷却系统的功用是保证发动机在正常的温度下工作，把发动机工作时产生的热量通过它散发出去，加以冷却，经常检查冷却系统的工作状况，不能有缺水、漏水或风向、风流、风量不对等现象，以免破坏发动机的正常工作，损坏机件，造成事故。冷却系统按发动机的冷却方式可分为风冷却和水冷却两种[1]。 1.风冷却系统 风冷却一般用于小型发动机上。依靠飞轮上的风扇叶旋转，产生气流，通过导风罩、引风圈、导风板等导风装置的导向作用，直接吹向气缸盖和气缸体的外表，将热量带走。气缸盖、气缸体外表上分布了很多散热片，它的功用是加大与空气的接触面积，提高散热能力。导风罩和引风圈、导风板的作用是将冷空气引导到需要冷却的部位，使各部位冷却均匀，达到维持其适宜工作温度的目的。若不用导风装置，则在气缸盖、气缸体等零件的背面就不能得到足够的冷却，使之温度过高，造成很大温差，引起气缸和其他零件变形，严重时还会发生活塞拉缸和卡死等故障。 2．水冷却系统 水冷却系统的主要部件有水泵、散热水箱、风扇、水温调节装置和水温表。按冷却水循环方式的不同，小型柴油机的冷却系可分为三种：蒸发式冷却、热对流循环式冷却、压流循环式冷却。 ①蒸发式冷却。发动机工作时，气缸体水套和气缸盖水套中的水因接触高温零件而温度升高，这部分水受热膨胀，密度减小，便上升到水箱的顶部，水箱表层的水受到外界空气的冷却，密度加大而下沉，分别进入缸体水套和缸盖水套，形成上下对流，连续不断地循环，从而将气缸体和气缸盖周围的热量带到水箱散发掉。当水箱内的水温升高到沸点时，缸体水套和缸盖水套内水逐渐变成水蒸气，冲击水箱水面散发到空气中去。蒸发式水冷却系统靠水沸腾吸收大量的热并散发到空气中去，加强散热冷却作用。因此，水箱常常出现“开锅”现象，这是正常的，应注意经常补充冷却水，以保证发动机的正常工作温度。 ②热对流式循环冷却。立式195T 和德力1105型柴油机的冷却系统属于此种冷却方式，利用水的温度差所引起的密度变化形成水的热对流自然循环，当柴油机工作时，气缸体水套与气缸盖水套的冷却水由于接触高温零件而温度升高，密度变小，沿上水管进入水箱的上水室，而水箱内的冷却水因密度较大靠自重而进入下水室，经下水管进入气缸体水套和气缸盖水套，缸体水套和缸盖水套的低温水受热后密度变小又上升进入上水室，水箱内的冷却水下沉到下水室进入缸体水套和缸盖水套，如此往复，使冷却水连续不断地循环，达到传热和散热的目的. ③压流循环式冷却。多缸发动机和泰山12型拖拉机配置的195T型柴油机的冷却系统，利用离心式水泵将水加压进行强制循环，主要由水泵、散热器、轴流式风扇及进水橡胶管等组成，散热器及其蒸汽空气阀的结构同热对流循环式相同。发动机工作时，曲轴通过三角皮带，带动冷却水泵的叶轮旋转，冷却水以一定的压力进入气缸体水套、气缸盖水套和散热器上水室，受热的冷却水经散热器芯向下流动，被风扇吹来的大量冷空气冷却，流到散热器下水室，又被吸入水泵，再压入气缸体水套，实现冷却水的强制循环。 水冷却的效果跟冷却液有很大的关系，使用水作为冷却液已经不能满足现代柴油机的冷却要求。应用防冻液和水按不同的比例进行配置，并且添加一定量的