The Humphrey cycle is the thermodynamic cycle occurring detonation engines such as rotating detonation engines, the pulse detonation engines, and pulse compression detonation systems.
It may be considered to be a modification of the Brayton cycle in which the constant-pressure heat addition process of the Brayton cycle is replaced by a constant-volume (isochoric process) heat addition process.
[1] It is a form of pressure gain combustion.
Hence, the ideal Humphrey cycle consists of 4 processes: