Diesel Spray Measuring Device

The paper presents the results of liquid fuel radial distribution measurements of 25 different spray cross-sections at various distances from the injection nozzle.

The measurements showed that fuel drops, sprayed into the air, evaporated and the spray diameter increased. The calculation of evaporated fuel quantity was based on the volume of injected fuel and the amount of liquid fuel measured in each spray cross-section. For the purpose of measuring the liquid fuel in a spray we developed a device using ring electrodes to measure electric charge of the fuel, resulting from fuel rubbing against the injection nozzle metal parts and the measuring device electrodes. The temperature gradient in the ring electrode is caused by droplets hitting it at the velocity of 100 to 300 m/s. Their kinetic energy is instantly transformed into the thermal energy the consequence of which is the temperature gradient in the ring electrode. The crystal in which the temperature gradient exists is minor generator of electric charge. The electric charge was then led to a charge amplifier, where it was converted into electric current. Numerous tests proved good linearity and reliability of the measuring method.