Now, with R-134a, smaller compressors, and poor condensing, idle performance on many vehicles is very poor. Foreign makers with good performing TXV systems are gaining market share in the hotter areas of the country. This is making auto companies seriously consider eliminating fixed orifice tubes in future designs. Also, reduced emissions due to lower compressor power will be part of the decision. Fuel economy should be improved in hot ambient city traffic.
Environmental concerns loom very large today.
An emission test conducted on a 1997 Minivan by Southwest Research Institute showed the VOV significantly reduced emissions. I can send you the actual results. A major California police agency has been testing the VOV for the past two years in the hottest desert areas of the country. They report a drastic reduction in compressor failures. Idle cooling performance is improved by 10 F and more.