High temperature protection for IC engine - has two stage operation to give warning before cut out

摘要

The engine has a protective circuit supplied from the electrical system (1, 23) through a main switch (2). The supply is taken to a switching circuit (3) which has an external connection (4) to a temp. sensitive resistance element (5) at a suitable point within the engine. When the temp. rises to a dangerous or when there is a fault in the circuit the switch (6) in the switching circuit (3) operates to send an output signal to a second thermostatically operated switch (10). At dangerously high temps. this puts the output to a terminal (12) connected to a circuit (25) which shuts down the engine. At lower temps. it puts the output to a terminal (11) connected to an audible or visual warning circuit (24) thus ensuring safety without stopping the engine unnecessarily.