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www.acsource.com has these for many car makes except, of course, Toyota. I'm very interested in getting my AC working again, and thought this might be a nice addition. Anyone know of any companies that make these for Toyotas? Come to think of it, do we even have these on our cars? I don't know much at all about how AC works.


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5° - 12°F colder air (at hot idle)
Reduced compressor load and extended compressor life
Improved performance when converting from R-12 to R-134a
Improved city fuel economy & emissions
Improved performance in factory R134a systems

The Smart VOV (variable orifice valve) uses system pressure and refrigerant flow to move a metering piston relative to a fixed opening in the sleeve. The piston movement is resisted by an attached spring.

When idling at high ambient temperatures, the piston shifts to a smaller metering area similar to a TXV. This compensates for the reduced compressor output and increases the cooling performance. The Smart VOV also has a unique re-open feature which reduces compressor pressure for severe idle conditions.

At highway speeds, the Smart VOV operates on a large orifice. The net result is better performance than a TXV without the complexity or reliability concerns.

Unlike a TXV, which has constantly moving parts and small internal clearances, the Smart VOV is stationary during most operating conditions and has large internal clearances. Its low friction floating design insures smooth operation and extremely long life.
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That device appears to work much the same way as the PRV (pressure reducing valve) that's installed in the liquid line to the evaporator. This is fairly common in big Toyota cars lke the MKII, MKIII, and Cressida that have a high capacity A/C system.
 

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Personally, I can see how it could possibly improve the performance of some American made A/C systems that depend largely on a TXV (thermal expansion valve) and a liquid line with a fixed orifice size to control the flow of liquid refrigerant to the evaporator core. But IMHO, I'd have to say that this is just another example of an area where Toyota was thinking way ahead and designed the PRV (Pressure Reducing Valve) to do what this thing appears to accomplish. Who knows, maybe they got the idea from studying how the PRV works in well designed Japanese A/C systems. :wink: Don't get me wrong, it looks like a nifty device, but I'd have to say that Toyota has already incorporated the basic theoryof the VOV into the PRV.
 
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