Low coolant level protection system

Claim 1

In a vehicle having a radiator, the radiator having liquid coolant therein, the vehicle having an engine operated on fluid fuel, a fuel source and a conduit connecting the fuel source to the engine, a low coolant level protection system comprising: a. a probe extending within the upper portion of the radiator and insulated from it, the probe having conductive contact with the coolant when the coolant is at normal operating levels; b. a battery having one pole connected to ground and to the radiator providing continuity with the coolant herein; c. a relay having a coil, a normally open switch and a normally closed switch, the relay coil being in electrical series with said battery, said probe and to ground, whereby said coil is energized when continuity is made between said probe and coolant in said radiator; d. a solenoid valve having: 1. a fluid passageway therethrough connected in said conduit between said fuel source and engine of the vehicle; 2. a valve seat forming a part of said fluid passageway; 3. a solenoid in electrical series with said relay normally open switch, said battery and ground; 4. a plunger acted upon by said solenoid, the plunger having a sealing face engagable with said valve seat when the valve is in the closed position, the plunger sealing face having a shallow depth groove therein permitting restricted flow of fuel through the valve when the valve is in the closed position; and 5. a spring normally retaining the valve plunger in closed position except when said solenoid is energized to withdraw said plunger against said spring in which case unrestricted flow of fuel through the valve is provided; an indicator light in series with said relay normally closed switch said battery and ground; whereby when said coolant level in said radiator is at a normal operating level continuity is provided through said radiator, coolant and probe to energize said relay to close said normally open switch and thereby energize said valve solenoid, moving said plunger to the opened position allowing unrestricted fuel flow to said engine and wherein low coolant level causes continuity to be lost between said coolant and said probe, de-energizing said relay to open said normally open switch thereby de-energizing said valve solenoid, said spring serving to close said plunger against said valve seat, permitting only restricted fuel flow through said shallow depth groove in said plunger to said engine, said indicator light being energized when said relay coil is de-energized to indicate the condition of low coolant level.