System pressure controlling method for coolant circuit for internal-combustion engine, involves determining coolant temperature in coolant circuit, and determining reference pressure by pressure temperature characteristic curve

摘要

The method involves measuring pressure in a coolant circuit by a pressure sensor (18). Reference pressure in the coolant circuit is adjusted with respect to deviation from the pressure in the coolant circuit by supplying or discharging gaseous medium i.e. compressed air, into a gas chamber (14) of a fluid reservoir (10). Coolant temperature in the coolant circuit is determined, and the reference pressure is determined by a pressure temperature characteristic curve. The pressure of the medium is limited by a pressure control valve (28) while supplying the gaseous medium into the chamber.