Determining fill level of engine cooling system

摘要

A cooling system of a motor-vehicle internal-combustion engine has a pump driven by a current-consuming electrical motor. The liquid fill level of a this system is determined by continuously and concurrently monitoring current consumption of the electrical motor and generating an output corresponding thereto. The output is continuously compared with at least one threshold and a difference between the output and the threshold is established as the fill level of the cooling system. An alarm signal is emitted when the output drops below the threshold. When the output is compared with two separate such thresholds one of which is lower than the other, the signal is emitted when the output drops below the lower threshold. It is also within the scope of this invention to emit the alarm signal when the output drops to a level somewhat above the threshold, the difference being determined electronically by the control system serving as comparator.