The pressure control valves commonly used today have elastomer membranes and are unable to resist the attacks of aggressive chemicals. Now with RobustPlus MANN+HUMMEL has developed a new material for pressure control valves which offers the highest chemical resistance.
Malfunctioning pressure regulation valves especially in gasoline engines in markets with variable fuel quality cause quality problems in the automotive industry: the limited chemical resistance of the elastomer membrane made from fluorosilicone rubber (FVMQ) leads to increased and quicker ageing. In combination with mechanical loads, the risk that cracks are formed increases. This results in uneven running of the engine up to the possibility of a stoppage or oil leak. Problems frequently occur in engines which run just a few kilometers or up to 80,000 kilometers. Also fabric-reinforced FVMQ offshoots or the use of fluorocarbon rubber polymers (FKM) do not represent a real alternative.
The developers at MANN+HUMMEL have now found a solution: a new fully fluorinated polymer. This has passed all the common standard tests and also proven its virtually universal chemical resistance and durability in extended tests under real driving conditions and even under unnecessarily severe testing conditions.
Conventional test fuels and standard tests are only partly true to reality. Therefore, we have considerably extended our series of standard tests. The test results of the RobustPlus pressure regulation valve partly exceed the requirements by a factor of ten. And that was even achieved with the doubling of the number of cycles, e.g. with switching tests over the whole temperature range between - 40 °C and + 150 °C. The tests included measurement of the tightness, burst pressure and regulation characteristic. In addition to the standard tests, an examination of the abrasion resistance, tendency to buckle and robustness of the new MANN+HUMMEL design was carried out. The RobustPlus membrane passed all the evaluation tests with flying colors.