Investigations have shown that it is not the new refrigerants themselves which are the cause of the changed requirements, but rather the compressor oils which have become necessary because of them and which are also circulating in the air-conditioning circuit. “Extended exposure of the materials to oil in a coolant atmosphere at high temperatures really separates the men from the boys,” declares Mike Eismann, Head of R&D in the Air Conditioning segment. In the tests hose samples are stored in oil and coolant at high temperatures in order to test the material resistance.
To meet the new challenges, ContiTech had to adapt the hose materials in some products or even develop new products, such as barrier hose 4882 for R1234yf and R744 solutions. “We are currently still working on an improvement to our high-temperature film hose,” reports Eismann. “As far as the other applications are concerned, we are already offering our customers the optimal product solutions.”
The extensive performance tests which follow the material tests and which differ from customer to customer are tying up a significant proportion of the Air Conditioning segment’s testing capacity. But Eismann is confident of concluding the validation for the new refrigerants by the middle of next year.