Mathematical model of the condensation process in a cylinder of a piston engine

BACKGROUND: In recent years, there has been a trend of increasing activity towards the development of polar territories. A characteristic feature of the North is negative ambient temperatures that have a negative impact on the condition of piston engines of ground transport, mobile and stationary power plants and labor saving tools. An engine is the least adapted unit for use in such conditions. There is a chain of negative factors that consistently links negative ambient temperatures, in which the equipment is operated, and the condition of the mechanisms and engine systems. The primary link of this chain is condensation processes. The existence of condensation processes during low-temperature operation of the engine has been experimentally proved. The latter takes place when warming up in conditions of negative ambient temperatures. The question «How much water changes the state during the warm-up period?» arises.

AIMS: Development of a mathematical model that makes possible to obtain unbiased information about the activity of condensation processes and to estimate the amount of water that changes the state during the warm-up period.

METHODS: Solving the given tasks is based on classical theories describing operational processes of boilers. The high labor intensity and significant financial costs in organizing such experiments require the search for new research methods. Mathematical models help to solve the task of defining the mass amount of water condensing in a cylinder of a piston engine computationally.

RESULTS: The mathematical model that is characterized by its adaptation to piston engines and is capable of determining the mass amount of water changing the state during the warm-up period iteratively, using the differences in partial pressures and the density of the mass flow of water condensate, has been developed.

CONCLUSIONS: The existence of water has a negative impact on conditions of a piston engine. The information about the amount of water condensing in a cylinder during the warm-up period stimulates to continue studies in the field of motor oils watering, active acids formation and corrosive wear of surfaces of details.