Upload
zachary-russo
View
221
Download
3
Tags:
Embed Size (px)
Citation preview
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
1. Combustion engines main principles and definitions
2. Reciprocating combustion engines architecture
3. Reciprocating engines dynamic properties
4. Engine components and systems
5. The engine management system for gasoline and Diesel engines
6. The emission Requirements & Technology
7. Engine vehicle integration8.
7.1 Engine layout and mounting7.2 Engine-vehicle cooling system7.3 Intake system7.4 Exhaust system
Light and heavy vehicle technology (Malcolm James Nunney - Elsevier)
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Cooling system
System Targets
To extract from the engine the heat quantity necessary to
maintain the working temperature of every engine components
below the safety limit in any vehicle operating condition.
To assure the thermal balance between the heat extracted
from the engine hardware and the heat released to external
ambient through the heat exchanger (radiator) even in the most
severe vehicle operating conditions.
2
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Critical engine components
Combustion chamber walls
Cylinder wall
Cylinder head
Piston
Exhaust valve
Spark plug
Gasoline / Diesel injector
Engine lubricants
Cooling system
3
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Centrifugal pump
Cooling fluid
Radiator
Fan
Thermostat
System components Function
Cooling fluid circulation
Heat transfer
Heat exchange with the ambient
Air through the radiator at low vehicle speed
Engine temperature stabilization
Cooling system
4
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Expansion tank (nourice)
Filler pressure cap
Passenger compartment radiator
Lubricant radiator
EGR cooling radiator (Diesel)
Fluid expansion and gas release
Cooling circuit pressure
Passenger compartment heating
Engine lubricant cooling
Exhaust gas cooling
System components Function
Cooling system
5
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Heat transfer fluid Etilene glycol mixture in water (30 –60% concentration)
Water
High specific heat
Low viscosity
High heat of vaporization
Constant characteristics vs time and temperature
Etilene glycol
High thermal capacity
Low pressure drop
Low gas formation
Low freezing point
Cooling system
6
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 7
EG Weight Percent (%)
Freezing Point (deg F)
Freezing Point (deg C)
0 32 0
10 25 -4
20 20 -7
30 5 -15
40 -10 -23
50 -30 -34
60 -55 -48
70 -60 -51
80 -50 -45
90 -20 -29
100 10 -12
Ethylene glycol freezing point vs concentration in water
Cooling system
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
SCHEMA CIRCUITO ACQUA MOTORE 1910 JTD - 8V - EURO 4 (impiego per FIAT e GM)
motore
riscaldatore
radiatore
term
osta
to
EG
R C
oole
r
pom
pa
nourice
scambiatore acqua/olio
spurgo A
spurgo B
spurgo C
Cooling circuit scheme
Cooling system
8
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Engine-Vehicle cooling system
LEGENDALEGENDA
1 RADIATORE CON CONVOGLIATORE E 1 RADIATORE CON CONVOGLIATORE E VENTOLEVENTOLE
2 VASCHETTA DI ESPANSIONE2 VASCHETTA DI ESPANSIONE
3 MANICOTTO DA RADIATORE A POMPA3 MANICOTTO DA RADIATORE A POMPA
4 MANICOTTO DA RISCALDATORE A 4 MANICOTTO DA RISCALDATORE A POMPAPOMPA
5 RISCALDATORE ABITACOLO5 RISCALDATORE ABITACOLO
6 MANICOTTO DA TERMOSTATO A 6 MANICOTTO DA TERMOSTATO A RISCALDATORERISCALDATORE
7 POMPA7 POMPA
8 MANICOTTO DA RADIATORE A TURBO 8 MANICOTTO DA RADIATORE A TURBO
9 MANICOTTO DA TERMOSTATO A 9 MANICOTTO DA TERMOSTATO A RADIATORERADIATORE
10 MANICOTTO DA TURBO A POMPA10 MANICOTTO DA TURBO A POMPA
11 TERMOSTATO11 TERMOSTATO
Cooling system
9
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Thermal balance equations 1/6Thermal balance equations 1/6
hkJigwuf QQQQQ
fQ
uQ
wQ
gQ
iQ
= heat introduced into the engine through the fuel combustion
= work equivalent heat at the engine shaft
= heat realeased to the engine cooling system
= heat rejected to the exhaust gases
= lost heat for radiance
where:
General equation for engine thermal balance
Cooling system
10
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Hi = net calorific or lower heating value (KJ/Kg)
mf = fuel consumption (Kg/h)
Heat released to the engine
hkJfm•
i=H
fQ
Heat released to the cooling fluid
hkJm
Teq
AKw
Q
K = heat transfer coefficient (KJ/m2°Kh)
Aeq = heat transfer equivalent surface area (m2)
= average difference in temperature between the exhaust gas and
the coolant (°K)
mT
where:
where:
Thermal balance equations 2/6Thermal balance equations 2/6Cooling system
11
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
cw = (KJ/Kg°K) water calorific value (4.1868 KJ/KgK)
mw = (Kg/h) coolant flow rate
Twu = (°K) coolant temperature at the engine outlet
Twe = (°K) coolant temperature at the engine inlet
cl = (KJ/Kg°K) lubricant calorific value
ml = (Kg/h) lubricant flow rate through the water-lubricant heat exchanger
Tlu = (°K) lubricant temperature at the outlet of the heat exchanger
Tle = (°K) lubricant temperature at the inlet of the heat exchanger
hkJwe
T-wu
Twmw
cw
Q
hkJT-TmcT-TmcQ lelullwewuwww
where:
Heat released to the cooling fluid from the engine
where:
Heat released to the cooling fluid from the engine and the water-lubricant heat exchanger
Thermal balance equations 3/6Thermal balance equations 3/6Cooling system
12
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Kr = (KJ/m2°Kh) heat transfer coefficient of the cooling radiator
Ar = (m2) radiator frontal area
Trm = (°K) average tempearture of the coolant inside the radiator
Heat released to the external ambient through the cooling radiator
hkJT-TAKQ aermrrw
K
2ru
Tre
T
rmT
Tae = (°K) air temperature at the radiator inlet which differs from the ambient
temperature Ta when the condenser radiator of air conditioning system
is installed ahead
where:
Thermal balance equations 4/6Thermal balance equations 4/6Cooling system
13
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Ta = (°K) ambient temperature
Tboil = (°K) boiling temperature of the coolant at the pressure of the circuit
Tre = (°K) temperature of the coolant at the radiator inlet
Air Temperature to Boil index (ATB): it defines the ambient temperature boiling point of the cooling fluid ( It represents an equilibrium condition between the heat rejected from the combustion gases to the cooling fluid and the heat rejected from the fluid to the external air for a specific vehicle operation mode.
KTTTATBreboila
Thermal balance equations 5/6Thermal balance equations 5/6
where:
Cooling system
14
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
ATB index vs Qw
ATB index could be expressed as function of the heat to be rejected from the engine into the coolant and of the radiator exchanging performances.
Without air conditioning system (Tae = Ta)
KTT
AK
Q2TATB aeru
rr
wboil
With air conditioning system
KTTTT
AK
Q2TATB aeaaeru
rr
wboil
ATB index expresses an equilibrium condition determined by the engineering design of the cooling system. ATB index expresses an equilibrium condition determined by the engineering design of the cooling system. Practically some ATB values are defined for some severe operating vehicle modes that represents the project targets.Practically some ATB values are defined for some severe operating vehicle modes that represents the project targets.
Thermal balance equations 6/6Thermal balance equations 6/6
where Kr [Kw/m2·°K] is a performance exchanger parameter of the radiator
Cooling system
15
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 16
The water pump provides circulation of the engine coolant (antifreeze) through the cooling system: it pushes the coolant through the passages (water jackets) in the engine cylinder block and cylinder head and then out into the radiator. The hot coolant passes through the radiator where it cools down and then returns back to the engine.
Centrifugal pump is the most used:it is a rotodynamic pump that uses a rotating impeller to increase the pressure and flow rate of a fluid. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward or axially into a diffuser or volute chamber, from where it exits into the downstream piping system.
A water pump is usually driven by the engine through the driving belt and only sometimes by a timing belt. A water pump consists of the housing with the shaft rotating on the bearing pressed inside. At the outer side there is a pulley mounted on the shaft. At the inner side there is a seal to keep the coolant from leaking out and the impeller.
Cooling systemComponent – Water pump 1/5Component – Water pump 1/5
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
• Impeller diameter ( = 60 75 mm)
• Impeller height (h = 12 20 mm)
• Paddles number and design (z = 5 10)
• Axial and radial impeller clearance
• Drive ratio
engine
pump
n
n = 1.3 1.6
Main design characteristics
Component – Water pump 2/5Component – Water pump 2/5Cooling system
17
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Typical values
Tw = 8 – 10°C
/Pm = 0.030 – 0.043 Kg/sKw for gasoline engines
0.025 – 0.035 Kg/sKw for Diesel engines
Typical system back pressure
0.5 2.5 bar
Setting of the coolant flow rate
The coolant pressure at the pump inlet must not be negative to avoid cavitations phenomena and therefore the inlet speed shall be limited, generally lower than 3 m/s.
Component – Water pump 3/5Component – Water pump 3/5Cooling system
18
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 19
Hydrodynamic cavitation describes the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of a decrease and subsequent increase in pressure. Cavitation will only occur if the pressure declines to some point below the saturated vapor pressure of the liquid. In pipe systems, cavitation typically occurs either as the result of an increase in the kinetic energy (through an area constriction) or an increase in the pipe elevation.Hydrodynamic cavitation can be produced by passing a liquid through a constricted channel at a specific velocity or by mechanical rotation through a liquid. In the case of the constricted channel and based on the specific (or unique) geometry of the system, the combination of pressure and kinetic energy can be created when the hydrodynamic cavitation cavern downstream of the local constriction generating high energy cavitation bubbles.The process of bubble generation, subsequent growth and collapse of the cavitation bubbles results in very high energy densities, resulting in very high temperatures and pressures at the surface of the bubbles for a very short time. The overall liquid medium environment, therefore, remains at ambient conditions. When uncontrolled, cavitation is damaging; however, by controlling the flow of the cavitation the power is harnessed and non-destructive. Controlled cavitation can be used to enhance chemical reactions or propagate certain unexpected reactions because free radicals are generated in the process due to disassociation of vapors trapped in the cavitating bubbles.
Component – Water pump 4/5Component – Water pump 4/5Cooling system
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Typical water pump characteristic (63.5mm impeller diameter, 8 paddles of 13.5mm height, axial clearance of 0.6mm, engine drive ratio 1/1.39)
POMPA ACQUA 1250 JTD (H) Prestazioni rilevate su motore completo
0
500
1000
1500
2000
2500
3000
3500
0 2000 4000 6000 8000 10000 12000
Portata liquido [l/h]
p
[m
ba
r]
5000 n/1 - 1,6 bar
4500 n/1 - 1,6
4000 n/1 - 1,6
3000 n/1 - 1,6
2000 n/1 - 1,6
1000 n/1 - 1,6
caratteristica impianto
5450
Component – Water pump 5/5Component – Water pump 5/5Cooling system
20
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 21
Target - In internal combustion engines a thermostat is used to maintain the engine at its optimum operating temperature by regulating the flow of coolant to the external air cooled radiator. It must balance the heat rejected from the engine to the coolant and the heat rejected from the radiator to the ambient in any operating vehicle mode.
This type of thermostat operates mechanically: it makes use of a wax pellet inside a sealed chamber. The wax is solid at low temperatures but as the engine heats up the wax melts and expands. The sealed chamber has an expansion provision that operates a rod which opens a valve when the operating temperature is exceeded. The operating temperature is fixed, but is determined by the specific composition of the wax, so thermostats of this type are available to maintain different temperatures, typically in the range of 70 to 90°C. Modern engines run hot, that is, over 80°C, in order to run more efficiently and to reduce the emission of pollutants. Most thermostats have a small bypass hole to vent any gas that might get into the system, e.g., air introduced during coolant replacement, which also allows a small flow of coolant past the thermostat when it is closed. This bypass flow ensures that the thermostat experiences the temperature change in the coolant as the engine heats up; without it a stagnant region of coolant around the thermostat could shield it from temperature changes in the coolant adjacent to the combustion chambers and cylinder bores.
Wax thermostatic elements permit the transforming of thermal energy into mechanical energy. Their working principle is based on the large increase in the thermal expansion of waxes when they pass from the solid to the liquid state
Cooling system Component – Thermostat 1/4Component – Thermostat 1/4
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 22
While the thermostat is closed, the flow of coolant in the loop is greatly slowed, allowing coolant surrounding the combustion chambers to warm up rapidly. The thermostat stays closed until the coolant temperature reaches the nominal thermostat opening temperature. The thermostat then progressively opens as the coolant temperature increases to the optimum operating temperature, increasing the coolant flow to the radiator. Once the optimum operating temperature is reached, the thermostat progressively increases or decreases its opening in response to temperature changes, dynamically balancing the coolant recirculation flow and coolant flow to the radiator to maintain the engine temperature in the optimum range as engine heat output, vehicle speed, and outside ambient temperature change. If the load on the engine increases, increasing the heat input to the cooling system, or the vehicle speed decreases or air temperature increases, decreasing the radiator heat output, the thermostat will open further to increase the flow of coolant to the radiator, preventing the engine from overheating. If the conditions reverse, the thermostat will reduce its opening to maintain the coolant temperature.
Cooling systemComponent – Thermostat 2/4Component – Thermostat 2/4
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 23
Under normal operating conditions the thermostat is open to about half of its stroke travel, so that it can open further or reduce its opening to react to changes in operating conditions. A correctly designed thermostat will never be fully open or fully closed while the engine is operating normally, or overheating or overcooling would occur. For instance, If more cooling is required, e.g., in response to an increase in engine heat output which causes the coolant temperature to rise, the thermostat will increase its opening to allow more coolant to flow through the radiator and increase engine cooling. If the thermostat were already fully open, then it would not be able to increase the flow of coolant to the radiator, hence there would be no more cooling capacity available, and the increase in heat output by the engine would result in overheating. If less cooling is required, e.g., in response to decrease in ambient temperature which causes the coolant temperature to fall, the thermostat will decrease its opening to restrict the coolant flow through the radiator and reduce engine cooling. If the thermostat were already fully closed, then it would not be able to reduce cooling in response to the fall in coolant temperature, and the engine temperature would fall below the optimum operating range. Modern cooling systems contain a relief valve in the form of a spring-loaded radiator pressure cap, with a tube leading to a partially filled expansion reservoir (most recent applications use to have the pressure cap directly on the expansion reservoir – see slides 25/26). Owing to the high temperature, the cooling system will become pressurized to a maximum set by the relief valve. The additional pressure increases the boiling point of the coolant above that which it would be at atmospheric pressure.The wax product used within the thermostat requires a specific process to produce. Unlike a standard paraffin wax, which has a relatively wide range of carbon chain lengths, a wax used in the thermostat application has a very narrow range of carbon molecule chains. The extent of the chains is usually determined by the melting characteristics demanded by the specific end application. To manufacture a product in this manner requires very precise levels of distillation, which is difficult or impossible for most wax refineries.
Cooling system Component – Thermostat 3/4Component – Thermostat 3/4
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Typical thermostat characteristicOpening temperature 882 °C
Valve stroke of 9.5mm at 101105 °C
0
2
4
6
8
10
12
80 85 90 95 100 105 110
temperatura [°C]
co
rsa
va
lvo
la [
mm
]
ISTERESI 1.3 °C
1-Cooling systemComponent – Thermostat 4/4Component – Thermostat 4/4
24
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 25
Main target
To absorb the expansion of the coolant as it gradually increases into full operating temperature.
To generate pressure at the pump inlet to avoid cavitations phenomena.
To remove bubbles from the entire cooling system to absorb heat much faster.
To assure a coolant reservoir sufficient for the maintenance-free target
To fit the filler neck (the mouth of the header tank) covered with a pressure cap, which forms an air-tight joint due to which the coolant is maintained at some pressure higher than the atmospheric (generally 1.4-1.6 bar). Using the pressure cap brings about the following advantages in the cooling system: Elevating the boiling point: the engine can operate at higher temperatures without boiling the liquid coolant within. Allows for the usage of smaller tanks for the same engine sizes. Prevents any coolant to be wasted or drained away and maintains a self regulated system that can go maintenance free.
Component – Component – EExpansion reservoir and pressure cap 1/51-Cooling system
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 26
The reservoir is connected to the radiator that it receives the excess coolant as the engine temperature increases. When the liquid cools down, its volume decreases and the coolant in the reservoir returns to the reservoir to keep the coolant level in the cooling system optimal. This system is also known as coolant recovery system and it helps to prevent loss of coolant, doesn’t allow air to come into the system and allows for a smaller header tank. The expansion tank is a see-through plastic container that has to be mounted into the overflow tube from the radiator. With a properly working expansion bottle, radiator is always full even if the coolant inside it rises and falls. As a general rule, standard expansion tank volume is approximately 20 to 30-percent of the estimated volume of the specific thermal fluid of the system circuit. A pressure cap contains a pressure valve and a vacuum valve. If in severe operating conditions, the coolant starts to boil or to vaporize, the pressure in the system builds up and exceeds a certain pre-determined value , the pressure blow-off value, which operates against a pre-tensioned spring, opens releasing the excess pressure to the atmosphere through the over flow pipe.
Component – Component – EExpansion reservoir and pressure cap 2/51-Cooling system
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
The expansion tank should be located about the level of the radiator header tank.
Component – Component – EExpansion reservoir and pressure cap 3/51-Cooling system
27
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Typical installation of the expansion reservoir inside a complex layout of the engine bay for a small segment vehicle
Component – Component – EExpansion reservoir and pressure cap 4/51-Cooling system
28
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
3 Control functions
1 - Filler neck sealing
2 - Max pressure control
3 - Min pressure control (vacuum valve)
Pressure cap
Component – Component – EExpansion reservoir and pressure cap 5/51-Cooling system
29
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Air liquid heat exchanger (radiator) composition
• Core heat exchange
• Two tanks cooling collection & release
Heat exchange core made by stacked layers of pipes
Material (high thermal conductivity)brassaluminum
Technologymechanical expansion & interferencebrazing
1-Cooling system Component – Component – RadiatorRadiator
30
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 31
A radiator is a type of heat exchanger. It is designed to transfer heat from the hot coolant that flows through it to the air blown through it by the fan.
A typical radiator consists of a header tank, the core and the lower tank: both of these tanks have water outlets.
The water coolant mixture is cooled while it flows into the radiator’s core which is made of thin, flattened aluminum small tubes with aluminum fins outside which are present only to help increase the rate of heat transfer (secondary heat transfer surfaces). The tubes sometimes have a type of fin inserted into them called a turbulator, which increases the turbulence of the fluid flowing through the tubes.
The core is usually made of stacked layers of metal sheet, pressed to form channels and soldered or brazed together. For many years radiators were made from brass or copper cores soldered to brass headers. Modern radiators save money and weight by using plastic headers and may use aluminum cores. This construction is less easily repaired than traditional materials.
1-Cooling system Component – Component – RadiatorRadiator
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Tubes
Ailettes
DMS
DMS: 23R7 60µ av Ailett e Diabolo 12/99 ? ? effet Volume effet Volume ?
actuel prévu actuel prévu actuel prévu actuel prévu actuel prévu actuel prévu actuel prévu
Ep. tube 0,35 0,325 0,35 0,325 0,35 0,325 0,35 n/a 0,35 n/a 0,35 0,3
Ep. d'ailette 0,077 0,060 0,077 0,060 0,077 0,060 0,077 n/a 0,077 n/a 0,077 0,07
1,15
A A7072 H19
1,0 - 1,05 - 1,15
8006/8011/1230 H19
Itatiba
3003 F 3103 F
Pas d'ailettes 1,0 - 1,05 - 1,15
Site de production Laval Saragossa
1,0 - 1,05 - 1,15
1050 H19
3003 H12 3103 H18
St Luis Potosi
Matière3003 H12
Pologne
A A3003 H18
1100 H19 1050 H19
3103 H12
1100 H19
Actions de productivité
23R7
Frosinone Greensburg
1,0 - 1,15
02/2000
3003 H18
1100 H19
1,15
Tubes
Ailettes
pour l e t ube dé c-00
actuel prévu actuel prévu actuel prévu actuel prévu actuel prévu actuel prévu actuel prévu
Ep. tube 0,38 0,33 0,38 0,33
Ep. d'ailette 0,077 0,07 0,077 0,07
Site de production Laval Saragossa
Matière
Actions de productivité
Pas d'ailettes 1,0
18V14
1,0 - 0,90
1050 H191050 H19
Gre ensburg St Luis Potosi
3103 H12
Frosinone
3103 H12
Pologne Itatiba
(épo xy )
Tubes
Ailettes
pour l e t ube dé c-00
actuel prévu actuel prévu actuel prévu actuel prévu actuel prévu actuel prévu actuel prévu
Ep. tube 0,38 0,33 0,38 0,33
Ep. d'ailette 0,077 0,07 0,077 0,07
Site de production Laval Saragossa
Matière
Actions de productivité
Pas d'ailettes 1,0
18V14
1,0 - 0,90
1050 H191050 H19
Gre ensburg St Luis Potosi
3103 H12
Frosinone
3103 H12
Pologne Itatiba
(épo xy )Tubes
Ailettes
pour l e t ube dé c-00
actuel prévu actuel prévu actuel prévu actuel prévu actuel prévu actuel prévu actuel prévu
Ep. tube 0,38 0,33 0,38 0,33
Ep. d'ailette 0,077 0,07 0,077 0,07
Site de production Laval Saragossa
Matière
Actions de productivité
Pas d'ailettes 1,0
18V14
1,0 - 0,90
1050 H191050 H19
Gre ensburg St Luis Potosi
3103 H12
Frosinone
3103 H12
Pologne Itatiba
(épo xy )
Typical main and secondary (louvers) fins of a aluminum brass radiator
Fins of an aluminum mechanical built radiator(oval and elyptical tubes)
Twin row brazed radiator
1-Cooling system Component – Component – RadiatorRadiator
32
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Automotive cooling radiators with horizontal tanks and with vertical tanks
Tank material -PA 66 glass reinforcedTank material -PA 66 glass reinforced
1-Cooling system Component – Component – RadiatorRadiator
33
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Radiator thermal performance per surface unit depend on
Material
Construction technology
Radiator thickness
Tubes and fins passo/technology
brass
brazing
18 – 34 mm mechanical techn.18 – 40 mm brazed techn.
Manufacture patents
Air velocity (flow rate)
Coolant velocity (flow rate)
Air velocity (flow rate)
Coolant velocity (flow rate)Heat exchanged per surface area unitHeat exchanged per surface area unit
Air pressure drop
Coolant pressure drop
Air flow rate
Coolant flow rate
1-Cooling system Component – Component – RadiatorRadiator
34
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
ConstructionTechnology
Radiator thickness[mm]
Heat exchangecapacity[W/dm2 °C]
Interference mech.
18 40.2
Interference mech.
32 46.4
Brazed 13 41.6
Brazed 18 46.0
Brazed 27 64.1
Brazed 40 70.8
Heat Transfer Capacity in Kalories (W) per dm2 and per °C of Heat Transfer Capacity in Kalories (W) per dm2 and per °C of temperature difference between coolant and airtemperature difference between coolant and air
( ) ( )hkJae-TrmTr
Ar
Kw
Q =
1-Cooling system Component – Component – RadiatorRadiator
35
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
0
10
20
30
40
50
0 2 4 6 8 10 12 14
Varia [m/s]
Sc
am
bio
te
rmic
o s
pe
cif
ico
[W
/dm
2 °C
] Vliq 1 m/s
Vliq 1.5 m/s
Vliq 1.75 m/s
0
10
20
30
40
50
0 2 4 6 8 10 12 14
Varia [m/s]
Sc
am
bio
te
rmic
o s
pe
cif
ico
[W
/dm
2 °C
] Vliq 1 m/s
Vliq 1.5 m/s
Vliq 1.75 m/s
Specific heat transfer of an aluminum interf. mech. radiator (Alm) 580x317x18 (LxHxP)
Specific heat transfer of an aluminum brazed radiator (Alm) 580x305x18 (LxHxP)
1-Cooling system Component – Component – RadiatorRadiator
36
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Air pressure drop of some radiators
0
100
200
300
400
500
600
700
0 2 4 6 8 10 12
Varia [m/s]
P
[P
a]
rad. 580x317x18 Alm
rad. 580x322x18 Als
rad. 580x405x28 Als
0
100
200
300
400
500
600
0 0.5 1 1.5 2 2.5
Vliq [m/s]
P
[m
ba
r]
rad. 580x317x18 Alm
rad. 580x322x18 Als
rad. 580x405x28 Als
Coolant pressure drop of some radiators
1-Cooling system Component – Component – RadiatorRadiator
37
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 38
The primary task of the fan is to generate sufficient air flow rate at low engine speed or more generally when the coolant temperature exceeds a set point.
Front-wheel drive cars have electric fans (150-600W) because the engine is usually mounted transversely, meaning the output of the engine points toward the side of the car.
The fans are controlled either with a thermostatic switch or by the engine electronic system (ECU), and they turn on when the temperature of the coolant goes above a set point, they turn back off when the temperature drops below that point.
Rear-wheel drive cars with longitudinal engines usually have engine-driven cooling fans. These fans have a thermostatically controlled viscous clutch. This clutch is positioned at the hub of the fan, in the airflow coming through the radiator.
1-Cooling system Component – Component – FanFan
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 39
Core face to fan distance is the distance from the fan blade face and the next cooling component inline, typically the radiator core. This distance is critical to proper airflow and to the durability to the fan. If the distance is too close the air flow will focus on only that portion of the core that is covered by the fan blades, rendering the core section covered by the center hub section of the fan useless. If the fan is too close there will also be a constant flexing of the fan blades due to the proximity of the core face and some air pressure gradient problems. For more efficient use of the whole radiator core surface, the fan is shrouded in the most severe applications.
Typical engine-driven cooling fan application for a longitudinal engine installation
1-Cooling system Component – Component – FanFan
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
el
aerst
PP
Electrical fan stationary efficiency (ca.40%)
Air flow power [W]
where:
a
Paaer a
.
mP
Electrical power absorbed by the fan [W]
Air flow rate[kg/s]
Air density [kg/m3]
Back pressure [Pa]
Electrical motor voltage [V]
Current adsorbed by electrical motor [A]
a.m
Pel = V I
V
I
DPa
1-Cooling system Component – Component – FanFan
40
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Coooling air
Shrouded mono and twin fan
1-Cooling system Component – Component – FanFan
Coooling air
Up front fan
41
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
500W fan typical performance (380mm blade diameter)
0
50
100
150
200
250
300
350
400
0,00 0,20 0,40 0,60 0,80 1,00 1,20 1,40 1,60 1,80
Portata Aria kg/s
Pre
va
len
za [
Pa
]
0,0
5,0
10,0
15,0
20,0
25,0
30,0
35,0
40,0
45,0
50,0
Co
rre
nte
as
so
rbit
a d
al m
ot.
ele
ttri
co
[A
] R
en
dim
en
to [
%]
Dp ventola
Corrente mot. elettrico
Rendimento
1-Cooling system Component – Component – FanFan
Optimal working area
42
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 43
Engine oil lubricates and cleans moving / rotating metallic surfaces. As metallic surface rub on each other, that causes friction, thus creating heat. Heat is the enemy to motor oil. As motor oil heats up it loses its ability to lubricate and the surfaces requiring lubrication begin to wear. Continued use at elevated temperatures can result in premature engine wear and eventual failure.
Engine oil coolers are commonly used on higher performance engines, heavy duty commercial vehicles, vehicles with increased trailer towing capacity, and most high speed diesel engines. As engines become more efficient engine oil coolers will become common on most motor vehicles.
The general target is to avoid oil temperature exceeding 160-180°C in the most severe operating conditions, but generally the cooling system is design and set to keep a constant temperature around 120-130°C.
Component – Component – Oil coolerOil cooler1-Cooling system
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 44
Filter Mounted Engine Oil CoolerThis type of engine oil cooler is designed to be mounted onto the engine block with a hollow bolt and uses the engine water as cooling fluid. The oil flow is as follows: engine oil leaves engine and enters the oil cooler, circulates through the oil cooler, exits oil cooler and enters oil filter, oil is filtered and returns to engine through the hollow mounting bolt. The cold fluid comes from the radiator circuit. Optimal performance will be achieved if the cold fluid can be taken from the exit side of the radiator (cooled water/glycol).
Engine Mounted Engine Oil CoolersThis type of engine oil cooler is designed to be mounted directly onto the engine block. The oil flow is as follow: engine oil leaves the engine and enters the oil cooler, circulates through the oil cooler, exits oil cooler and re-enters the engine. The cold fluid can either be routed to the heat exchanger in 2 ways: 1) fed from the radiator circuit through flexible lines or, 2) fed directly into the heat exchanger from the engine block, eliminating the need for additional lines. Optimal performance will be achieved when the hot oil and cold fluid (glycol/water mixture) have the greatest inlet temperature difference.
Component – Component – Oil coolerOil cooler1-Cooling system
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 45
Remote Mounted Engine Oil CoolerThis type of design is normally mounted remotely from the engine block. This design is well suited to applications where additional engine oil cooling is required over the original design intent of the vehicle (I.e. increased trailer tow, large engine displacements and racing applications).There are 2 types of designs and mounting strategies in this class of engine oil coolers.
Mounted directly in an air stream (most often in front of the radiators). Cooling occurs by passing hot oil through the cooler via fluid lines coming from the engine and ambient air passing through the core of the oil cooler. Liquid-to-liquid remote oil cooler. Engine oil and coolant are both fed to the oil cooler via fluid lines coming from the engine and coolant circuit respectively. This design can be mounted anywhere there is room to package under the hood. Optimal performance will be achieved when the hot oil and cold fluid (glycol/water mixture or air) have the greatest inlet temperature difference.
Most common applications for this design can be found on heavy-duty trucks, large displacement engines and racing or high speed applications.
Component – Component – Oil coolerOil cooler1-Cooling system
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 46
Component – Component – Oil coolerOil cooler
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
0
50
100
150
200
250
300
350
400
450
500
15 20 25 30 35 40 45
Portata olio [l/min]
Pot
enza
term
ica
[W/°
C]
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
Cad
uta
di P
ress
ione
[kP
a]
Coolant Flow = 20 L/min
Coolant Flow = 30 L/min
Coolant Flow = 40 L/min
Oil Side Pressure Drop
Filter Mounted Engine Oil Cooler – Thermal performances80x140mm e 12 layers (oil 140 °C, coolant 82 °C)
Component – Component – Oil coolerOil cooler1-Cooling system
47
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Remote Mounted Engine Oil Cooler – Thermal performances200x150x30 mm (oil 100 °C, air 20°C)
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
0.03 0.08 0.13 0.18 0.23Portata olio [l/s]
Po
ten
za te
rmic
a [k
W/K
]
0
50
100
150
200
250
300
350
400
Ca
du
ta d
i Pre
ssio
ne
inte
rna
[kP
a]
Portata aria - 2m/sPortata aria - 4m/sPortata aria - 6m/sPortata aria - 8m/sPortata aria - 10m/sDP olio
Component – Component – Oil coolerOil cooler1-Cooling system
48
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 49
An intercooler (original UK term, sometimes aftercooler in US practice), or charge air cooler, is an air-to-air or air-to-liquid heat exchange device used on turbocharged and supercharged (forced induction) internal combustion engines to improve their volumetric efficiency by increasing intake air charge density through nearly isobaric (constant pressure) cooling. The general target is to cool the compressed air down to below 60°C at the engine intake.
aeai
aoai
- Air temperature at intercooler inlet
- Air temperature at intercooler outlet
- Temperature of the ambient cooling air
TaiTaoTae
where:
Component – Component – IntercoolerIntercooler1-Cooling system
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science 50
Tai
Tao
TURBOCHARGER
ENGINE
Brick type air to air intercooler Full Face air to air intercooler
Component – Component – IntercoolerIntercooler1-Cooling system
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Intercooler performance characteristic (280x130x50). Charge air temperature 140°C, ambient air temperature 30°C (ETD external temperature difference = 110°C)
Component – Component – IntercoolerIntercooler1-Cooling system
51
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Cooling system designCooling system design
Engine protection
Reduced packaging of the radiator/fan module
Minimized system cost
ATB index
Vehicle design & aerodynamic penetration
Product competitivity
Design targets
1-Cooling system
52
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
In the most severe vehicle operating modes the engine outlet temperature must
not exceed
100° - 105°C for long time
110° - 115°C for limited time
V=30 Km/h1° gear9% slope with trailer equal to the vehicle weight
V=140 Km/hLongest gearMax engine power
ATB = Ta + Tboil - Tre
Low vehicle speedATB = 40°C
High vehicle speedATB = 60°C
Engine protection targets
Two severe conditions
ATB design target
Cooling system designCooling system design1-Cooling system
53
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Radiator performance characteristic
Heat to be rejected at the high speed severe driving mode
with Tru calculated from the the temperature drop through the radiator by
Design target
Kr [Kw/m2·°K]
∆Tr[°K]
Qw[Kw]
ATB
The radiator frontal area can be calculated by:
In theory, being knowed:
_r
ATBΔT
2
1TK
QA
rebr
wr
aru
T_T
Cooling system designCooling system design
Cooling module design
1-Cooling system
54
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Radiator size defined by the layout constraints
In real practice:
A value of air flow rate trough the radiator is estimated at the vehicle speed of the high speed ATB target
By iterative approach, type and thickness of the radiator are selected so that the Kr coefficient can satisfy the following equation:
ATBΔT
2
1TK
QA
rebr
w
r
Cooling module design
Cooling system designCooling system design1-Cooling system
55
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Exchanged heat coefficient Kr vs air flow rate of a typical automotive cooling radiator
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Portata aria [kg/s]
Co
effi
cien
te s
cam
bio
ter
mic
o K
r [k
W/m
2 /K]
7200 kg/h
5000 kg/h
3000 kg/h
Cooling module design
Cooling system designCooling system design1-Cooling system
56
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Through the radiator performance characteristic by Qw heat to be rejected at the low speed mode it can be defined
Fan selection and design (Low speed ATB)
The necessary air flow rate
Electrical fan is selected from a catalogue suitable for the specific layout and able to deliver the necessary air flow
rate at maximum fan efficiency
Cooling system designCooling system design1-Cooling system
57
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Rejected heat vs air flow rate for a typical radiator
10
15
20
25
30
35
40
45
50
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Portata aria [Kg/s]
Po
ten
za t
erm
ica
scam
bia
ta [
kW]
7200 Kg/h
5000 Kg/h
3000 Kg/h
Performance characterisric of a typical electric fan
0
50
100
150
200
250
300
350
400
0,00 0,20 0,40 0,60 0,80 1,00 1,20 1,40
Portata Aria [kg/s]
Pre
vale
nza
[P
a]
0,0
5,0
10,0
15,0
20,0
25,0
30,0
35,0
40,0
45,0
Co
rren
te a
sso
rbit
a d
al m
ot.
ele
ttri
co [
A]
Ren
dim
ento
[%
]
Dp ventola
Corrente mot. elettrico
Rendimento
Cooling system designCooling system design1-Cooling system
58
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Design criticities during the project development
Difficult estimation of the air flow rate through the radiator
Different power train to be installed on the same vehicle (different Qw)
Continuous evolution of the engine compartment layout during development
Optimized process for the project design development Design phase
Approximate calculationApproximate calculation
Mono-dimensionalanalysis
Mono-dimensionalanalysis
Experimental checkExperimental check
Three-dimensionalanalysis
Three-dimensionalanalysis
Design conceptDesign concept
Design developmentDesign development
Design validationDesign validation
Cooling system designCooling system design1-Cooling system
59
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Input dataInput data OutputOutput
Coolant flow rate, rejected engine and oil cooler heats, exchange heat and perssure drop radiator characteristics….engine power and torque curve, vehicle features and front end design and air permeability , total gear ratio…
CAD file: Vehicle extrenal design Cooling module installation Engine bay layout for the major
components
Coolant flow rate, rejected engine and oil cooler heats, exchange heat and perssure drop radiator characteristics….engine power and torque curve, vehicle features and front end design and air permeability , total gear ratio…
CAD file: Vehicle extrenal design Cooling module installation Engine bay layout for the major
components
Air speed distribution through the radiator surfacea rea
ATB index
Coolant temperature at the engine outlet
Air speed distribution through the radiator surfacea rea
ATB index
Coolant temperature at the engine outlet
Accurate estimation of the air speed distribution
Accurate estimation of the air speed distribution
High work load and long time
High work load and long time
AdvantagesAdvantages
DisadavantagesDisadavantages
Three-dimensional analysisThree-dimensional analysis
Cooling system designCooling system design1-Cooling system
60
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
CFD analysis: examples of calculation output. Under bonnet air speed and temperature map at two different vehicle speeds
Cooling system designCooling system design1-Cooling system
61
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
CFD analysis: examples of calculation output. Air speed and temperature distribution through radiator at two different vehicle speeds
Cooling system designCooling system design1-Cooling system
62
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
CFD and test results comparison
ATB exp. test
1° gear at 30 km/h 9% slope with trailer A/C OFF
5° gear at140 km/h full load A/C ON
Testing data 3D simulation
Heat to be rejected
[kW]
Air T[°C]
ATB [°C]
ATB [°C]
22.5
30.1
29.7
30.7
60
75.3
101
84.8
61.2
77.1
Rad inlet temperature
102.3
87.9
Rad inlet temperature
Cooling system designCooling system design1-Cooling system
63
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Heat (Qw) rejected to the coolant
Test equipment
Engine test bench Temperature, flow meter,
engine parameters ….
Test equipment
Engine test bench Temperature, flow meter,
engine parameters ….
Prerequisites
Engine design conformity Coolant flow rates
representative of the vehicle configuration
Prerequisites
Engine design conformity Coolant flow rates
representative of the vehicle configuration
Measurement of
Coolant temperature at the engine inlet (Twe) and outlet (Twu)
Coolant flow rate (mw) Engine speed Engine torque
At ATB operating conditions
Measurement of
Coolant temperature at the engine inlet (Twe) and outlet (Twu)
Coolant flow rate (mw) Engine speed Engine torque
At ATB operating conditions
°
°Qw = Cw · mw · (Twu -Twe)
64
Cooling system designCooling system design1-Cooling system
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Heat rejected to the coolant as % of the engine power measured on the test bench (gasoline engine 1242cc 16v 80 CV, diesel engine 1910cc 8v 105 CV
65
Heat (Qw) rejected to the coolant
3000 32 533500 38 524000 45 504500 53 475000 59 48
2000 44 612250 50 522500 56 542750 59 523000 63 473250 67 483500 70 503750 74 514000 75 544250 75 57
Rilascio termico all'acqua in % della Potenza Utile
Potenza Utile [kW]
Motori Benzina
Motori Diesel
Regime motore [gg/min]
Cooling system designCooling system design1-Cooling system
Engine Vehicle Integration
Scuola di Dottorato di Ricerca 2010 - Road vehicle and engine engineering science
Test equipment
Chassis dynomometer inside climatic chamber
Tempertaure and pressure measure devices
Test equipment
Chassis dynomometer inside climatic chamber
Tempertaure and pressure measure devices
ATB test measurement
Procedure
When engine temperature is stabilized at the vehicle load & speed defined by ATB targets, it has to be measured the ambient and radiator inlet temperatures
Procedure
When engine temperature is stabilized at the vehicle load & speed defined by ATB targets, it has to be measured the ambient and radiator inlet temperatures
Prerequisite - Conformity of
Engine and electronic management system
Vehicle and vehicle system, particularly front end and engine bay layout
Cooling module (radiator and fan) Pressure cap
Prerequisite - Conformity of
Engine and electronic management system
Vehicle and vehicle system, particularly front end and engine bay layout
Cooling module (radiator and fan) Pressure cap
ATB = Ta + Tboil - TreATB = Ta + Tboil - Tre
Cooling system designCooling system design1-Cooling system
66