#31
|
|||
|
|||
رد: الفرق بين تكييف السيارات القديمة والحديثة والمنزل
بعد التحية
هل ينفع اركب تكيف مكروباص على سيارة 5 راكب صغيرة لزيادة التبريد وشكرا للرد؟ التعديل الأخير تم بواسطة basselelsaedy ; 23-09-2011 الساعة 05:11 PM |
#32
|
|||
|
|||
رد: الفرق بين تكييف السيارات القديمة والحديثة والمنزل
ممكن اعرف ما هو ابرد فريون ممكن اشحن بية السيارة فية ابرد من فريون 22 مثلاا؟
|
#33
|
|||
|
|||
رد: الفرق بين تكييف السيارات القديمة والحديثة والمنزل
Evaporator controls
Evaporator controls are used to control the temperature of the evapora- tor by regulating the flow of refrigerant through the evaporator. (Of course, the evaporator temperature is also controlled by the cycling of the compres- sor, which indirectly controls the flow of refrigerant through the evaporator.) Evaporator controls are used mainly on older U.S.-built vehicles with com- pressor which run constantly. Evaporator controls are seldom found on mod- ern U.S. vehicles, or on any European or Japanese vehicles. Evaporator controls help prevent freezing and help keep the air condi- tioning system operating efficiently. As already noted, the flow of refrigerant through the evaporator is the key to the efficient operation of an air condi- Heating and air conditioning tioning system. Sometimes, under certain operating conditions, the conden- sation which forms on the outside of the evaporator may freeze, which can block the evaporator fins, and reduce the airflow through the evaporator. This reduces the evaporator's cooling ability, and thus the cooling efficiency of the system. The most commonly used evaporator controls include the: Suction throttling valve (STV) Pilot Operated Absolute Suction Throttling Valve (POA STV) Valves-In-Receiver (VIR) Evaporator-Equalized Valves-In-Receiver (EEVIR) Evaporator Pressure Regulator (EPR) valve Suction Throttling Valve (STV) The suction throttling valve (STV) was used on some early expansion valve type air conditioning systems to control the refrigerant flow leaving the evaporator. In an air conditioning system that uses an STV, the compressor is running constantly as long as the system is switched on. A typical STV opens or closes in response to refrigerant pressure to keep the pressure in the evaporator within a predetermined range. This maintains the evaporator temperature at a level that ensures efficient operation of the air conditioning system without allowing the evaporator to freeze up. Pilot Operated Absolute Suction Throttling Valve (POA STV) Most modern STVs are of the pilot operated absolute (POA) type. A POA STV (see illustration) is really nothing more than a spring-loaded valve, con- trolled by an evacuated bellows and needle valve assembly inside a housing. The valve operates independently of atmospheric pressure, and is unaf- fected by changes in altitude. By providing an opposing force to evaporator pressure, the valve can maintain the evaporator pressure with a high degree of accuracy (within a 1 psi range). As long as the evaporator pressure remains above a predetermined level, the POA STV remains open to allow refrigerant t o flow freely out of the evap- orator. When the pressure drops below the predetermined level, the valve loses, and the refrigerant flow from the evaporator is restricted. The pres- sure in the evaporator then increases, which raises the temperature and prevents icing on the outside of the evaporator. The opening and closing cycle of the valve continues as long as the compressor is run- ning. Valves-In-Receiver (VIR) The valves-in-receiver (VIR) unit (see illustra- tion) combines the functions of an expansion valve, a POA STV and a receiver/drier into one assembly. The VIR is usually installed near the evaporator. In a VIR unit, the temperature-sensing bulb and capillary tube for the expansion valve are eliminated because the diaphragm end of the expansion valve is directly exposed t o the refrigerant vapor entering the VIR as- sembly from the evaporator outlet. Evaporator-Equalized Valves-In-Receiver (EEVIR) The evaporator-equalized valves-in-receiver (EEVIR) unit is a modified version of the VIR. It has a redesigned expansion valve in order t o eliminate temperature fluctuations in the system which occur under certain operating conditions. The expansion valve is also modified so that it is always partly open instead of completely closed. This helps t o prevent freezing at the expansion valve (which will block the flow of refrigerant and prevent the system from op- erating). Evaporator Pressure Regulator (EPR) valve The evaporator pressure regulator (EPR) valve (see illustration) is usually installed at the inlet port of the compressor. The valve maintains the evapora- tor outlet pressure within predetermined limits. An EPR valve performs the same function as the STV. Typical Evaporator Pressure Regulator (EPR) valve Driveability controls An air conditioning compressor takes a significant amount of power to run (on average, somewhere between 10 and 1 5 horsepower), and the effect of compressor operation, in conjunction with other demands placed on the engine, can impose loads which reduce vehicle performance. This is a signif- icant problem on vehicles with small capacity engines. Driveability controls are used to control the operation of the compressor to relieve the load on the engine under conditions when driveabllity may suf- fer. These controls don't usually affect the cooling performance of the air conditioning system. On most modern vehicles equipped with engine man- agement systems, the compressor clutch is controlled by the electronic con- trol unit (ECU) or the powertrain control module (PCM). The compressor is controlled in accordance with the information received from the various en- gine management system sensors, to ensure that the driveability of the vehi- cle doesn't suffer. This reduces the need for separate driveability controls. Typical driveability controls include the: Time delay relay Wide-open throttle switch Closed throttle switch Low vacuum switch Power steering pressure switch Power brake switch Engine coolant high temperature switch Constant run relay Compressor delay timer Anti-dieseling relay High-pressure relief valve التعديل الأخير تم بواسطة mbx4e ; 04-06-2012 الساعة 04:41 PM |
#34
|
|||
|
|||
رد: الفرق بين تكييف السيارات القديمة والحديثة والمنزل
بسم الله ماشاء الله عزوجل موضوع جميل واعضاء اجمل ياريت بس تلخصوا الكلام ده كله فى معلومات بسيطة ومحددة علشان نقدر احنا كمان نفهم زيكم الاهم من الشرح المعلومة الدوغرى والتطبيق بتاعها فى الواقع العملى التكييف لما بيبوظ مش بيرجع تانى زى الاول حد بقى فى نهاية الموضوع يقولى ليه ويقولى بديل الصمام لما يبوظ ايه ؟ وعند مين ؟ ماركته وسعره وهل عملى لانى حابب اعرف معلومة تنفع فى المستقبل هو ده المفيد ومشكورين على الموضوع الجامد فعلا ربنا يجازيكم عنا خير |
#35
|
|||
|
|||
رد: الفرق بين تكييف السيارات القديمة والحديثة والمنزل
ايه المواضيع الجامدة ده ... ماشاء الله
مجهود رائع و نقاشات اروع |
|
|