MARMARA ÜNİVERSİTESİ TEKNOLOJİ FAKÜLTESİ · Otomobil Ekipmanları Üzerine Çevresel Etkiler Environmental wind tunnel Thermal wind tunnel ... Commercial test environments

Otomobil Ekipmanları Üzerine

Çevresel Etkiler

Environmental wind tunnel

Thermal wind tunnel

Climatic wind tunnel

Abdullah DEMİR, Yrd. Doç. Dr.

MARMARA ÜNİVERSİTESİ TEKNOLOJİ FAKÜLTESİ

The purpose of environmental testing

Evaluating the worth of manufactured goods is not limited to evaluating their function and performance. • At what level can performance be maintained, and for how long? In other words,

what is the product failure rate? • How does performance change in response to the severity of the

environment actually encountered? That is to say, a crucial part of the worth of manufactured goods is in their quality. However, when quality defects occur after products have been put on the market, the cost is not limited to the significant amount that can be lost in the damages. The greatest loss is in the loss of reputation. To avoid such damages, quality must be confirmed before a product is put on the market. Environmental testing not only confirms quality through such tests as simulation testing and product life testing, it also can truly be called the indispensable prerequisite to quality assurance. Environmental testing can be broadly categorized, as shown in Fig., into “Climatic (natural) environmental testing” and “Mechanical (causal) environmental testing” as well as a combination of the two, “Combined environmental testing”. Climatic-related environmental testing deals with environmental factors such as pressure, humidity, and temperature, while mechanical environmental testing treats such factors as shock and vibration.

Yoshinori Kin/Yasuko Sasaki, Understanding the Technology, What is Environmental Testing?

Types of environmental testing


Table 1: Environmental factors of climatic environmental testing and their major effects


Gusting: Kuvvetli rüzgar Precipitation: Yağmur Hail: dolu yağmak Sleet: sulu kar

Table 1: Environmental factors of climatic environmental testing and their major effects


Environmental Coverage Checklist (Typical)

Potential Environments:

Vibration (random, sine)

High Temperature

Low Temperature

Temp Cycling

Humidity

Pressure

Voltage

Mechanical Actuations

Effect of atmospheric conditions The quantity of air which an engine draws in, or is inputted to the engine by supercharging, depends upon the ambient atmosphere's density; colder, heavier, denser air increases engine output . Rule of thumb: Engine power drops by approximately 1 % for each 100 m increase in altitude. Depending upon engine design, the cold intake air is normally heated to some degree while traversing the intake passages, thereby reducing its density and thus the engine's ultimate output. Humid air contains less oxygen than dry air and therefore produces lower engine power outputs. The decrease is generally modest to the point of insignificance. The warm humidity of air in tropical regions can result in a noticeable engine power loss. Rule of thumb: Yaklaşık hesap, göz

kararı, pratik iş görme usulü.

Shipping and Storage

Environmental Stresses


Environmental Stresses on Automotive Equipment

http://www.theriac.org/DeskReference/viewDocument.php?id=282

Operating Environmental

Stresses


Automotive Handbook

Climatic factors Climatic stress factors acting upon automotive components encompass the effects of the natural environment, i.e. the macroclimate, and influences stemming from the vehicle itself (such as fuel vapor) and the microclimate within a component (such as the heat generated in electrical devices).

Temperature and temperature variations The range extends from extremely low temperatures (storage, transport) all the way to the high temperatures associated with operation of the internal-combustion engine.


Automotive Handbook

Atmospheric humidity and variations This range embraces everything from arid desert climates to tropical environments, and can even extend beyond these under certain conditions (as occur for instance when water is sprayed against a hot engine block). Humid heat (high temperatures combined with high atmospheric humidity) is especially demanding. Alternating humidity results in surface condensation, which causes atmospheric corrosion.

Mutlak nem: 1 m³ hava içinde bulunan nemin g olarak ağırlığına mutlak nem denir. Su buharı miktarı hacim itibariyle hiçbir zaman havanın %4’ünü aşmaz. Bağıl (Nisbi) nem: Belirli bir sıcaklıktaki hava kütlesinin içinde bulunan nem miktarının, o sıcaklıkta alabileceği en fazla nem miktarına oranına bağıl nem denir. Bağıl nem havada bulunan nemin yüzde cinsinden değeridir. Bağıl nem havanın neme doyma oranını verir. http://www.cografyatutkudur.com/nem/nemlilik.html

Humid heat: Nem oranı yüksek yüksek sıcaklık.


Corrosive atmospheres Salt spray encountered when the vehicle is operated on salt-treated roads and in coastal areas promotes electrochemical and atmospheric corrosion. Industrial atmospheres in concentrated manufacturing regions lead to acid corrosion on metallic surfaces. When they are present in sufficient concentrations, today's increasing amounts of atmospheric pollutants (SO2, H2S, Cl2 and NOx) promote the formation of contaminant layers on contact surfaces, with the result that resistance increases.

Automotive Handbook

Key Terms • Electrochemical corrosion • atmospheric corrosion • acid corrosion • atmospheric pollutants

(SO2, H2S, Cl2 and NOx)

Notlar: H2S (Hidrojen Sülfür): Hydrogen sulfide (British English: hydrogen sulphide) is the chemical compound with the formula H2S. It is a colorless, very poisonous, flammable gas with the characteristic foul odor of rotten eggs. Ref: http://en.wikipedia.org

Elektro-Kimyasal Korozyon Olayları Elektro-kimyasal korozyon esasen anot rolündeki maddenin çözünmesidir. Elektrokimyasal korozyon ister mikro ölçekte ister makro ölçekte oluşsun korozyon hücresi ile modellenebilir.


Water Stresses of varying intensities result from rain, spray, splash, and hose water as encountered when driving in rain, during car and engine washes, and – in exceptional cases – during submersion.

Automotive Handbook


Aggressive chemical fluids The product in question must be able to resist the chemical fluids encountered in the course of normal operation and maintenance at its particular operating location. Within the engine compartment, such chemicals include fuel (and fuel vapor), engine oil and engine detergents. Certain components are confronted by additional substances, for example, brake-system components and the brake fluid used to operate them.

Automotive Handbook


Sand and dust Malfunctions result from the friction due to sand and dust on adjacent moving surfaces. In addition, under the influence of moisture, certain types of dust layers can cause current tracking in electrical circuits.

Automotive Handbook

Mobility test areas range from soft mud (.7 cone index) to sand (10 square-mile live dune) to snow and ice. Commercial test environments include ride and handling course, paved tracks for operational sustained speeds up to 180 mph, salt troughs and cobblestone roads.

Kaynak: Nevada Automotive Test Center Web Site


Solar radiation The sun's rays cause plastics and elastomers to age (a factor to be taken into account in the design of external, exposed components).

Climatic Wind Tunnel can simulate solar radiation, rainfall, and snowfall as well as temperature and humidity. It is an indispensable facility to test car air-conditioner performance and engine cooling performance. We have a track record of supplying various attachments such as our original Solar Radiation Drivers.

Automotive Handbook


Atmospheric pressure Fluctuations in atmospheric pressure affect the operation and reliability of differential-pressure components, such as diaphragms, etc.

Automotive Handbook


Laboratory simulation of stress Climatic and environmental conditions are simulated both according to standardized test procedures (DIN IEC 68 – Environmental testing procedures for electronic components and equipment) and in special field-testing programs designed specifically for individual cases. The goal is to achieve the greatest possible approximation of the stresses encountered in actual practice ("test tailoring").

Automotive Handbook IEC: International Electrotechnical Commission


Temperature, temperature variation and atmospheric humidity Simulation is carried out in temperature and climate chambers as well as in climate-controlled rooms which afford access to test personnel. The dry heat test allows evaluation of a component's suitability for storage and operation at high temperatures. Testing is not restricted to ascertaining the effects of heat upon operation; it also monitors influences on material characteristics. Depending upon the particular application (component mounted on body, engine, or exhaust system), the degree of heat can cover an extremely wide range. The stress time can be up to several hundred hours. Testing the product's operation under cold conditions devotes particular attention to starting behavior and changes in materials characteristics at low temperatures. The testing range extends down to – 40 °C for operation, and to – 55 °C for storage. At less than 100 hours, the actual testing times are shorter than those employed for dry heat.

Automotive Handbook


Temperature, temperature variation and atmospheric humidity (continue) A further test simulates temperature fluctuation between the extremes encountered in actual operation; the temperature gradient and the dwell time also contribute to determining the degree of stress. The dwell time must be at least long enough to ensure that the sample achieves thermal equilibrium. The different levels of thermal expansion mean that the temperature variations induce both material aging and mechanical stresses within the component. The selection of appropriate test parameters makes it possible to achieve substantial time-compression factors. Atmospheric humidity testing under steady-state damp heat (e.g., + 40 °C / 93 % relative humidity) is employed in the evaluation of a product's suitability for operation and storage at relatively high humidity levels (tropical climates).

Automotive Handbook

Absolute humidity is the mass of water vapor divided by the mass of dry air in a volume of air at a given temperature. The hotter the air is, the more water it can contain. Relative humidity is the ratio of the current absolute humidity to the highest possible absolute humidity (which depends on the current air temperature). A reading of 100 percent relative humidity means that the air is totally saturated with water vapor and cannot hold any more, creating the possibility of rain. This doesn't mean that the relative humidity must be 100 percent in order for it to rain -- it must be 100 percent where the clouds are forming, but the relative humidity near the ground could be much less.

http://science.howstuffworks.com/nature/climate-weather/atmospheric/question651.htm


Corrosive atmospheres Salt fog is produced by diffusing a 5 % NaCl solution at a room temperature of 35 °C. Depending upon the intended installation location, the test times can extend to several hundred hours. Cyclic salt fog is a combination test comprising the following: "salt fog, dry heat and damp heat". It yields a closer correlation with field results. The industrial-climate test comprises up to 6 cyclical alternations between an 8-hour dwell period at 40 °C / 100 % relative humidity at 0.67 % SO2 and 16 hours at room temperature. The pollutant test with SO2, H2S, NOx and Cl2 is performed either for single gases or as a multisubstance test. Testing is carried out at 25 °C / 75 % relative humidity with concentrations in the ppm and ppb ranges, and lasts up to 21 days. Sand and dust Dust simulation is carried using a device which maintains a dust density of 5 g per m3 in moving air. A mixture of lime (kireç) and fly ash is one of the substances employed.

Automotive Handbook

Environmental wind tunnel

Thermal wind tunnel

Climatic wind tunnel

-Örnekler-

BMW kicks testing efforts up a notch with new climatic complex, 21-Sep-2011, http://articles.sae.org/10211/

BMW’s Energy and Environment Test Centre (EVZ) was built to enhance and upgrade an already formidable collection of test capabilities within the BMW Group. The EVZ is a complex, comprising three large climatic wind tunnels, two smaller test chambers, nine soak rooms, and a complete support infrastructure. Within the multiple test facilities that make up the EVZ, nearly all environmental conditions can be simulated, which in turn reduces the dependence on on-road testing. Even more importantly, test conditions can be created accurately and with great repeatability, regardless of the time of year. The EVZ complex is located in Munich at the BMW "FIZ," the primary technology and development center within the BMW group, and is physically situated next to the new aerodynamic complex, the AVZ. This arrangement brings together vehicle development and validation to a single location, the advantages of which are numerous: the primary one being the proximity of a multitude of engineering and technology experts to a full range of test facilities. The initial planning of the EVZ facility began at the same time as the AVZ in 2003, but more fully evolved in 2006 when various firms were given study contracts to provide a schematic design for the facility. The design brief was to fit three climatic wind tunnels, a climatic chamber, an altitude chamber, preconditioning rooms, and various work areas into a pre-defined building envelope. To respond to the study, a joint venture was formed between MCE Stahl & Machinenbau, Imtech DeutschlandGmbH & Co. KG, and Aiolos Engineering Corp. Upon completion of the study, in December 2006, this joint venture was awarded a contract to design and build the final facility.


The three wind tunnel airlines are geometrically identical, but each wind tunnel fulfills different requirements. This arrangement allowed for a savings in capital cost (e.g. cooling systems and specific test equipment such as solar simulation or rain simulation), while maintaining test flexibility. Of the three wind tunnels, the environmental wind tunnel (UWK) offers simulation over the largest range of environmental conditions. The temperature range of this wind tunnel is from -20 to +55°C (-4 to +131°F), with humidity control up to 95% RH (non-condensing conditions) for positive temperatures. The UWK includes a full-spectrum solar simulation system, a rain simulation system, and a snow simulation system. In addition, this wind tunnel is equipped with a flat-belt drive for motorcycle testing. The environmental range of the thermal wind tunnel (KWK) is the most restricted. In this wind tunnel, the primary tests are conducted on cooling system performance and cooling airflow in which the KWK temperature range of 20 to 45°C (68 to 113°F) is sufficient. This wind tunnel does not have a solar simulation system, nor the ability to control humidity. The thermal wind tunnel can reach the highest wind speed, 280 km/h (174 mph), compared to a maximum wind speed of 250 km/h (155 mph) in the other two wind tunnels. The temperature range of the climatic wind tunnel (EWK) is from -10 to +45°C (+14 to +113°F) and it includes humidity control for temperatures above freezing. A full-spectrum solar simulation system is also included in this airline. In the EWK, thermal operational safety, cooling system performance, climatic control, and brake cooling tests are performed. Additionally, the EWK main fan is equipped with carbon-fiber blades, lowering fan inertia allowing for quicker wind speed response during highly dynamic tests.

The schematic of the environmental wind tunnel is shown. 1: Access for vehicle 2: Roller dynamometer 3: Fan 4: Nozzle 5: Collector 6: Heat exchanger 7: Humidity regulation 8: Solar simulation 9: Rain rig 10: Snow gun 11: Flow straightener 12: Boundary layer suction 13: Idle city flaps 14: Flat belt for motorcycles 15: Fuel station 16: Exhaust extraction



The two test chambers are much smaller than the wind tunnels and, therefore, offer a greater compromise on the aerodynamic simulation. These chambers will be used for tests that are less sensitive to aerodynamic influences. However, both chambers are equipped with a full four-wheel chassis dynamometer, manufactured and installed by Maha. The climatic chamber (KK) is the smallest chamber, with a nozzle area of just 1 m² (11-ft²). The climatic chamber will be used for cold-start tests, developmental tests of the interior heating and cooling system, and to test defrost and dehumidification cycles within the interior and at the front windscreen. The KK has a temperature range of -30°C to +30°C (-22 to +86°F), a top wind speed of 130 km/h (81 mph), and is equipped with full-spectrum solar simulation. The altitude chamber (EK) has a 2-m² (22-ft²) nozzle, a top wind speed of 250 km/h (155 mph), a temperature range of -30 to +45°C (-22 to +113°F), a full-spectrum solar simulation system, and is equipped with humidity control for non-freezing temperatures. The primary function of this facility is altitude simulation through the control of static pressure. Altitudes from 100 m (328 ft) below sea level to 4200 m (13,780 ft) above sea level can be simulated within the EK. Climatic wind tunnels have always been smaller than wind tunnels designed for aerodynamic development; it is not feasible to build such large climatic wind tunnels. As a result, the aerodynamic simulation within a climatic wind tunnel is compromised—i.e. boundary influences will be more prevalent. But, as more of the tests that have traditionally been performed on test tracks are moved into the climatic wind tunnel, the quality of the aerodynamic simulation becomes more and more important. To meet the needs of BMW today and in the future, the climatic wind tunnels were built to aerodynamic specifications that are comparative to (and in some cases, exceed) many purely aerodynamic facilities in use today, exclusive of nozzle size.


After completion of the aerodynamic commissioning and before actual vehicle testing, verification and correlation studies were carried out by BMW. These studies involved instrumenting several vehicles with temperature and flow measurement equipment for comparison studies to other test facilities, including the new AVZ, and to on-track measurements. In general, the test fidelity of the EVZ wind tunnels could be verified through flow comparisons to the AVZ and temperature comparisons to on-road tests. Small temperature deviations could usually be attributed to external sources or known limitations, such as slightly differing starting temperatures. However, slight temperature deviations could be consistently seen at the rear underbody of many of the test vehicles, indicating boundary layer influences. The validation tests were carried out in each of the EVZ wind tunnels. Several different vehicles were instrumented with thermocouples in various areas, including the engine, gearbox, cooling system, carriage, exhaust system, fuel tank, and fire protection. The general procedure required at least two independent measurements at the BMW test center in Miramas, France, and two measurements in at least one of the EVZ wind tunnels. The test matrix used speeds between 35 and 250 km/h (22 and 155 mph) and included matching environmental loads, such as uphill and downhill grades. In all cases, the operating modes (gear selection, engine speed, air-conditioning settings, temperature, and humidity) were all matched in the EVZ. In repeatability tests within the EVZ for air-conditioning and cooling system tests, it has been found that 95% of the measured temperatures are within a repeatability of ±1°C (1.8°F). This article is based on SAE International technical paper 2011-01-0167 by Trevor Bender, Aiolos Engineering Corp.; and Peter Hoff and Roland Kleemann, BMW AG.

Climatic Room

The first Behr wind tunnel went into operation in 1937

Research and Development in the Climatic Wind Tunnels in Stuttgart and Troy, Behr

Reading Text The road environment in the laboratory – state of the art Modern climatic wind tunnels set new standards for the simulation of environmental and driving conditions. For example, the specified values for uniformity of temperature distribution and speed at the nozzle outlet are achieved, while all dynamic driving cycles can be run and the noise level in the test section is well below the level previously regarded as normal for wind tunnels. This provides ideal conditions for using a climatic wind tunnel to run the acoustic tests in the vehicle interior. …In addition to definitions of the usual speed and climatic values, it is now also possible to simulate as required solar irradiation from all directions. In addition, as further confirmation of the pioneering concept and flawless technical implementation of the climatic wind tunnels, the flow quality approaches the level of aero-acoustic wind tunnels.


Reading Text A new dimension in research and development

The main function of a climatic wind tunnel is to check the air conditioning system of a vehicle, optimize the control algorithms and achieve the best possible coordination between the individual components of the A/C and engine cooling system. With this in mind, and having the additional option of running cooling capacity measurements at peak load in a wind tunnel specifically for this purpose, the climatic wind tunnel was designed on a “no compromise” basis. With a maximum speed of 130 km/h it allows measurements for automobile climate control and for partial loadings in the engine cooling system. With a maximum speed of 200 km/h and higher roller loads… Real situations replicated as required The climatic wind tunnels meet every challenge – every conceivable set of realistic driving situations, a very wide range of combinations and sequences of temperature, air humidity, solar irradiation and road load provide for extremely finely tuned settings. This means that the characteristic parameters of the cooling circuit can be run and replicated as required. All the required tests are run in a generously-dimensioned open test section, which is able to accommodate all vehicle sizes, right up to trucks. The chamber temperature can be set with a maximum deviation of ± 0.5 K, from minus 30°C to plus 50°C. The air humidity can be set with the same level of precision; a tolerance of ± 0.5 K for any dew point between 0°C and 95% relative humidity ranks among the top values in the industry today.


The climatic wind tunnel in Stuttgart. The design of the climatic wind tunnel in the USA is similar


The climatic wind tunnel in Stuttgart. The design of the climatic wind tunnel in the USA is similar.


Cabin Heating By The Sun For analysis of cabin heating by the sun, the climatic wind tunnels have a versatile solarium, providing for adjustment of the radiation intensity between 350 W/sq m and 1,200 W/sq m, with exact replication of the sunlight’s spectral distribution. To allow reproduction of any irradiation angle and sun position at any time of day, the solarium lamps are mounted on movable frames.


The flows through the vehicle interior are largely dictated by the pressure conditions around the entire vehicle, which means that the flow quality is particularly important. Whereas in earlier wind tunnels an opening of 6 sq m was regarded as generous for vehicle tests, in the climatic wind tunnels, featuring a flexible nozzle top section, the nozzle exit surface can be set not only to 6 sq m, but to 8 sq m for vans, or even 10 sq m for trucks. In addition to outstanding flow quality, the uniformity of flow speed (± 0.5%) and temperature distribution (± 0.5 K) also meet the most demanding requirements.

Low sound level For identification of the acoustic emissions from the A/C system penetrating into the vehicle interior and evaluation of those emissions, it is essential that the sound level be kept as low as possible. This is achieved in the climatic tunnels by the rigorous selection of individual components, which are then carefully matched to achieve optimum system performance.



Climate simulation. e.g.

icing up

Heat up. Cool down

Cooling in the soak room


Climate simulation. e.g.

icing up

Heat up. Cool down

Cooling in the soak room

Climatic Room - Vistoen

VISTEON CLIMATIC WIND TUNNEL This facility allows Visteon to drive design decisions and accurately predict real world vehicle performance of thermal systems. State-of-the-art technical equipment enables precise temperature stability during testing and allows fast changes of thermal conditions. The Climatic Wind Tunnel supports vehicle testing in a wide range of thermal and road load conditions. Climatic Wind Tunnel Air velocity of up to 225 km/h Executes tests in a temperature range from -

40 °C to +55 °C Flexible solar simulation system enables

reproduction of any global sun conditions 4-wheel dynamometer with a unique

adjustable wheelbase can absorb up to 235 kW Climatic Chamber

Static testing and function testing on a 2-wheel dynamometer

Preconditioning of up to three cars 2006 Visteon

Climatic Wind Tunnel

Visteon Climatic Wind Tunnel Testing Test capabilities 1. A/C system performance 2. Heater system performance 3. Engine cooling performance at vehicle top speed or vehicle peak load during simulated

mountain drives or trailer tow testing 4. Vehicle under-body temperature investigation for cooling system and heat protection

development in hot climate conditions 5. Window defrost and demist performance according to legal standards for homologation and

certification 6. Simulated day profiles of temperature, humidity, solar radiation and drive conditions for

standardised evaluation of thermal control algorithms Extended utilisation of the facility 1. Objective passenger thermal comfort (with thermal manikins) 2. Standardised and automated testing of automatic temperature control systems 3. Combined with other unique testing capabilities (Laser Laboratory, NVH Laboratory) 4. Combined with Climate Laboratory facilities (e.g. HVAC component and system testing,

airflow measurement) 5. Fuel consumption measurements (test environment from -40 to +55 °C)

2006 Visteon

Climatic Chamber and Wind Tunnel

2006 Visteon

http://www.audi.com/com/brand/en/company/wtc/Wind_Tunnels/thermal_wind_tunnel.html

Isıl (Termik) Rüzgar Tüneli The thermal wind tunnel Audi uses the thermal wind tunnel mainly to study the engine cooling system and the heat management. Vehicles are tested under extreme conditions in the tunnel, where temperatures can reach 55 degrees and air speeds can be pushed up to 275 km/h. In contrast to the aeroacoustic wind tunnel, the air flow in the thermal wind tunnel follows a vertical path. A powerful one megawatt fan operates in the upper storey above the test section, with a heat exchanger immediately behind it which heats the air continuously from +20 to +55 °C. The test section The test section is almost eight metres long; thanks to its heated, transparent floor, it offers maximum scope for observation and realistic testing of the vehicle. Unlike the aeroacoustic wind tunnel, the vehicle is supported on rollers. The twin-axle four-wheel roller dynamometer ensures that near-realistic simulation of various test cycles (uphill driving, trailer towing) can be simulated. The roller diameter is two metres and the brake output is 400 kW.

http://www.audi.com/com/brand/en/company/wtc/Wind_Tunnels/thermal_wind_tunnel.html

Isıl (Termik) Rüzgar Tüneli

Eliminating hot spots By using the thermal wind tunnel it is possible to make significant improvements to the thermal management in a vehicle. In order to produce a wide range of models with different engine combinations, it is essential to have sufficient cooling in all driving situations. No hot spots must be created in any part of the engine compartment. And it is also important to provide good cooling for auxiliary equipment. Checking calculations While it is true that cooling systems are designed basically by computer, testing is still necessary to check that the original requirements are being fulfilled. The development of the engine, condenser, charge air, brakes and the various oil circuits all rely on the thermal wind tunnel. Aerodynamic conditions Air flow through and around the vehicle are closely connected to each other, regardless of whether we are talking about a passenger car, off-road SUV or a sports car. The results obtained in the aeroacoustic wind tunnel have a bearing on tests performed in the two smaller wind tunnels – another benefit of bringing together the organisation of the three facilities on the Audi Wind Tunnel Centre site.

http://www.audi.com.tr/tr/brand/tr/experience/Wind_Tunnel_Centre/Wind_Tunnels/thermal_wind_tunnel.html#source=http://www.audi.com.tr/tr/brand/tr/experience/Wind_Tunne

l_Centre/Wind_Tunnels/thermal_wind_tunnel.detailview.Level1_0002_Level2_0012.html&container=layerModal

Audi - Isıl (Termik) Rüzgar Tüneli

Isıl rüzgar tüneli esas itibariyle motor soğutma sistemi ve ısı yönetimi incelemesi için kullanmaktadır. Sıcaklığın 55 dereceye ve hava hızının 275 km/h’ye kadar çıkarılabildiği bu tünelde araçlar çok zorlu koşullarda denenir. Aeroakustik rüzgar tünelinden farklı olarak ısıl rüzgar tünelindeki hava akımı düşey bir yol izler. Bir megawatt gücündeki fan, test bölümünün üzerindeki üst katta çalışır. Hemen arkasında havayı +20°C’den +55 °C’ye kadar ısıtabilen bir eşanjör vardır. Test bölümü: Neredeyse 8 metre uzunluğundaki test bölümü ısıtmalı, şeffaf tabanı sayesinde azami gözlem olanağı sunarak aracın gerçekçi olarak test edilmesini mümkün kılar. Aeroakustik rüzgar tünelinden farklı olarak araç rulolar üzerinde mesnetlenmiştir. Çift akslı, dört tekerlekli rulolu dinamometre, çeşitli test çevrimlerinin (yokuş çıkma, römork çekme) gerçeğe yakın bir şekilde simüle edilebilmesini sağlar. Rulo çapı iki metre ve fren gücü 400 kW’tır.

Kaynak: XC90 Kullanıcı El Kitabı - 2013

Okuma Parçası: Olumsuz sürüş koşulları

Uzun seyahatler için yağ seviyesini daha sık kontrol ediniz: • bir karavan veya römork çekme • dağlık bölgelerde • yüksek hızlarda • -30 °C'den düşük veya +40 °C'den yüksek sıcaklıklarda. Bu durumlarda anormal derecede yüksek yağ sıcaklıkları oluşabilir veya yağ tüketimi artar. Araç, kısa mesafelerde (10 km'den daha az) sürülüyorsa düşük sıcaklıklarda (+5 °C'nin altında) yağ seviyesi daha sık kontrol edilmelidir.

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MARMARA ÜNİVERSİTESİ TEKNOLOJİ FAKÜLTESİ · Otomobil Ekipmanları Üzerine Çevresel Etkiler Environmental wind tunnel Thermal wind tunnel ... Commercial test environments