A FAST-RESPONSE CATALYTIC HOT-WIRE SONIC NOZZLE PROBE TO MEASURE FUELCONCENTRATION IN A FUEL AIR MIXTURE

A new fuel concentration measurement technique, a catalytic hot-wire s onic nozzle probe, is described. This probe was tested in n-pentane/ai r, n-heptane/air and leadless gasoline/air mixtures. The results obtai ned show that the probe is very sensitive to fuel concentration even i n a rich mixture and has a high reproducibility. It can easily detect an amount of 0.2% mole fraction of gasoline in air. The estimated time response of this probe is less than 400 mus. The probe is simple in c onstruction and can be used to measure fuel concentration in cases whe re laser techniques are inappropriate due to optical inaccessibility o f a complex experimental set-up such as the combustion chamber of an e ngine.