This article describes a fuel jet injected at high pressure into ambient air. A new liquid fuel content measuring method was developed to detect fuel quantity on the basis of droplet electrical charge. The fuel is electrically charged as a result of its rubbing against the injection nozzles metal parts. Numerous tests have confirmed that the electrical charge is a good indication of liquid fuel content and proved good linearity and reliability for this new method. The radial liquid fuel distribution in the spray was measured at various points from the injection nozzle. The first cross section was located at a distance of 10 mm and each subsequent cross section at a further distance of 10 mm. The results of the measurements showed that the liquid fuel concentration was the highest on the spray axis and that it declined in the radial spray direction. The quantity of evaporated fuel across each cross section is calculated from the measured liquid fuel quantity and the total injected fuel volume.