New polymer pressure control valves pass endurance test

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 MANN+HUMMEL RobustPlus membrane sets new standards through its high resistance to chemicals and mechanical stress.

Lukas Bock, Design Engineer and Project Manager

Tested a million times

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.

Longest lifetime

With the completion of the first B samples, the new chemically resistant pressure regulation valve is shortly before its market launch. Particularly in the Chinese market, the new RobustPlus membrane promises a long lifetime and mileage, also under critical ambient conditions.

Advantages at a glance

  • Best chemical resistance
  • High bending strength
  • Low switching force
  • Tight connection after welding
  • Temper-proof design
  • ‘Extremely low’ permeation of hydrocarbons
  • High abrasion resistance
  • Temperature range: – 60 °C up to + 200 °C