We make use of the mass produced exhalation valve widely used in transport ventilators. The exhalation valve can offer performance similar to those used in ICU ventilators (preliminary data collected and shown in this page).
We use a proportional valve to control the pressure on the membrane of the exhalation valve. The control strategy and pressure profile is being optimized. In the current implementation, we open the exhalation valve completely (apply 0 pressure) at the beginning of exhalation cycle and ramp up the pressure for PEEP control.
PEEP = 5 cmH2O, 500 ms ramp
PEEP = 5 cmH2O, 0 ms ramp (open loop)
