Methods, systems, and devices are disclosed for injecting and igniting a fuel using corona discharge for combustion. In one aspect, a method to ignite a fuel in an engine includes injecting ionized fuel particles into a combustion chamber of an engine, and generating one or more corona discharges at a particular location within the combustion chamber to ignite the ionized fuel particles, in which the generating includes applying an electric field at electrodes configured at a port of the combustion chamber, the electric field applied at a frequency that does not produce an ion current or spark on or between the electrodes.