Presentation on theme: "A/C Design Verification Tests A/C Performance: –Conducted at 43 C (110F) –Vehicle is soaked till average interior temperature reaches 140 F and then tested."— Presentation transcript:
A/C Design Verification Tests A/C Performance: –Conducted at 43 C (110F) –Vehicle is soaked till average interior temperature reaches 140 F and then tested at 30 30mph, 60mph, 10min idle in drive and 20 min idle in Neutral. –Maximum head pressure requirement is 400 Psig at end of 30min idle
A/C Critical Parameters Compressor Endurance Test (New test starting model year) –Vehicle is tested at max speed and WOT, wide open throttle, at 100 F and 110F for 20 min followed by 10min idle in drive and 20 min idle in neutral –Maximum head pressure requirement is 320 psig during high speed and WOT and 400 psig at end of idle –Maximum compressor discharge temperature is 265 F
Future Improvements Ford Climate Control is phasing out scroll compressors on all Ford North American applications, replacing orifice tube with TXV for refrigerant control, and implementing high capacity condensers on all vehicle applications. By 2009 All vehicles will have piston pump compressors ranging from 150cc on small vehicles to 213cc on large vehicles. For 2007 programs, Econoline diesel will still have 115cc scroll compressor. Econoline gas will have 180cc piston compressor and New HD F-Series will have 213cc piston pump
Future Improvements The new piston pump compressors meet new Ford engineering specs. The new compressors are more robust for high speed, high head pressure, slugging and clutch cycling. By 2009, all vehicles will have high capacity condensers /2 HD F-Series and Econoline gas engines will have high capacity condensers. Econoline diesel will still have the regular capacity condenser.
Future Improvements By 2009 most of our vehicles will have TXVs replacing Orifice Tubes as refrigerant control devices to improve idle performance. Few applications such as HD trucks and Econoline will keep the orifice tube for the moment. Replacing orifice tubes with TXVs will require a different way of determining the proper amount of refrigerant charge when adding an aux unit for rear seating comfort.
A/C Critical Parameters To Watch When adding aux units or making changes to OEM designed system the following critical parameters should be monitored –Compressor head pressure should not go beyond 430 psig when idling for longer than 30 minutes at ambient above 95F –Compressor refrigerant discharge temperature (skin A/C line temperature) should not go higher that 265 F under extreme conditions (High speed/high ambient or long idle, more than 30 minutes at ambient above 95F) –Compressor refrigerant inlet temperature (Skin temp.) should not be colder than the evaporator out. This is an indication of compressor flooding. –Do not use copper brass heater cores or joints in the aux units.
A/C Critical Parameters To Watch Determining the proper amount of refrigerant charge and oil after adding aux units requires controlled environmental chambers. When this facility is not available, the following process should be followed –For system with Orifice tube in front and TXV in the Aux Run the system, both front and Aux in high blower speeds, open windows and air recirculation mode. Engine speed 1500 rpm, 90F or higher ambient (best if is 110F) Use and industrial fan to blow air in front of the condenser to simulate ram air to the front end. (This test can also be run at 40mph vehicle speed) Add refrigerant until the front evaporator inlet and outlet tubes skin temperature cross over. (Cross over is evap out temp cooler than evan in temp as refrigerant is added) Turn the aux system off and repeat the step above. Add 2 ozs of charge as charge protection. Monitor head pressure and discharge air temperature throughout this process. A slight increase in discharge air and head pressure are expected after adding the charge protection. As a rule of thumb adding an aux unit will require an additional 4 to 5 ozs of oil to the OEM front system label amount. Compressor discharge temperature should never go above 265F during the charge determination process.
A/C Critical Parameters To Watch TXV Selection for Aux System. –It is very important to select the proper TXV size when adding aux units. Oversize TXV will cause hunting that is evident in suction pressure rising and falling during normal operation. It also flood the compressor with liquid refrigerant that causes it to fail prematurely. Undersize TXV will cause poor performance and higher superheated gas to compressor that causes the compressor discharge temperature to reach its critical temperature of 265 F. Recommended super heat setting is 10F NOTE: NEVER USE ORIFICE TUBES FOR FRONT AND AUX SYSTEMS.
A/C Critical Parameters To Watch Summary Under all driving and weather conditions, the compressor discharge temperature should be under 265 F and compressor head pressure should be under 435 psig after idling for 30 minutes at ambient up to 110 F.
A/C Lines & Fittings The following information is critical to ensure the sealing and performance integrity of A/C lines and joints. –No thread sealer or Teflon tape on threads –Sealers do not work on orings and cause more problems –Hand crimping gives unequal forces on hoses leading to gross leaks or high leak rates –Adjust the screw fitting on the bottom of the TXV to change super heat setting (if super heat changes are required for TXV function) –Avoid dissimilar metals from touching Aluminum and steel touching create corrosion problems Use non conductive rubber to isolate the dissimilar metals Most sensitive on tubing, less on steel nuts touching blocks –Design or select components such that they dont create oil traps in the lines U shape line routing
A/C Lines & Fittings The following is a good practice to ensure proper function of A/C lines and joints –Protect underbody lines from stones with convolute or foam insulation –Route convolute or foam so that the slit is on the bottom of the assembly to avoid corrosion (Water accumulation) –Route lines away from heat sources (Exhaust pipes), heat will damage orings, hoses and crimps –Insulating suction line will improve performance –Use lines going to the rear that are equal to or less than ½ inch (Liq. Lines. For better performance) –Use lines coming from the rear that are equal to or larger than 5/8 (Suc. Lines. For better oil in circulation)
A/C Lines & Fittings Good practice Contd. –If possible remove shutoff or adapter valves that come with the front system –Recommended hose is Goodyear 4860 & 4890 or equivalent hoses with similar specs for liquid line –Recommended hose for suction line is Goodyear 4880 & 4869 or equivalent hoses with similar specs –Use only HNBR orings for connections –Keep orings and seals free of contaminations. Even very small hairs, dirt, lint and other debris will create leaks –Many joints are torque sensitive. Follow torque specs for all joints.
Recommended Single Fittings Dual Slimline Fitting, it contains a oring and compression fitting
Recommended Dual Fittings Single Slimline connections for Expansion Valves
Part Numbers and Components Currently there are many types of fittings that come on a Ford Vehicle. They include dual slimline, single slimline, face compression oring peanut, tube O, quick connects, single radial oring peanuts, and manifold blocks. Orings & seals are specific to its fitting type For any questions, contact your Body Builders Advisory Service Representative