Pressure and Temperature Relationships Which Might Be Used to Anticipate Coolant Boiling

The conventional temperature switch presently used to anticipate boiling in an automotive cooling system is not completely satisfactory under certain conditions. Following an analysis of cooling system phenomena, the possibility is suggested of sensing both temperature and pressure to anticipate boiling. The vapor pressure comparator, a combination temperature-pressure switch, is described and its performance is analyzed with respect to cooling system phenomena.