Influence of residues from aluminium brazing processes on automotive A/C systems at worst-case conditions

摘要

The paper describes the final results for the stability testing of R134a and PAG lubricant in the presence of Nocolok~® flux residues. A test rig has been erected to examine possible interactions between the flux residue and the refrigeration system, involving the refrigerant, the lubricant and the incorporated components. The stability of the refrigerant and the other incorporated materials at normal conditions as examined in the test rig have been described in previous publications (1). The present work describes the results of stability tests at elevated contents of moisture and acidity. These worst case scenarios were conducted with no filter dryer in place, with an artificially increased moisture content and with a very high surface area of flux residues in order to maximise any possible interactions between the flux and the other materials incorporated in the system.As well as stability tests in dynamic conditions, static thermal stability tests were also conducted. The results of the complete test program are summarised.