Automobile engine cooling system

A cooling system for an internal combustion engine having a radiator connected to said engine by way of a circulation passage for cooling and circulating engine coolant through said engine, said cooling system comprising:

• first valve means disposed in said circulation passage, said first valve means comprises a first thermostat valve starting opening at a first predetermined opening temperature to permit engine coolant to flow therethrough and a load valve located in series relative to said first thermostat load valve in said circulation passage, said valve being operated by actuator means to close for interrupting said flow of engine coolant through said first thermostat valve when said engine is operated in a low engine load range;
• second valve means comprising of a second thermostat valve disposed parallel to said first thermostat valve in said circulation passage, said second thermostat valve being adapted to start opening at a second predetermined opening temperature higher than said first predetermined opening temperature for said first valve means;
• a first bypass passage branching off from said circulation passage for allowing engine coolant leaving said engine to reenter into said engine while bypassing said radiator;
• a second bypass passage branching off from said circulation passage for allowing engine coolant leaving said engine to reenter into said engine while bypassing said radiator;
• and
• bypass valve means being cooperated with said first thermostat valve for closing said first bypass passage when said first thermostat valve is being opened.

A cooling system for an internal combustion engine having a radiator for cooling engine coolant leaving an engine and a water pump for circulating said engine coolant through said engine, said cooling system comprising:

• an inlet radiator passage connecting said engine to said radiator, said inlet radiator passage being partly divided into first and second separate passages parallel to each other;
• an outlet radiator passage in which said water pump is disposed;
• a bypass passage connecting an upstream part of said inlet radiator passage where said first and second separate passages are formed to said outlet radiator passage for allowing engine while bypassing said radiator;
• first valve means disposed in said first separate passage of said inlet radiator passage for permitting said engine coolant leaving said engine to flow through said first separate passage when said engine coolant is at temperatures higher than a first predetermined opening temperature and said engine is operated in low engine load range and interrupting said flow of engine coolant through said first separate passage when said engine is operated in a low engine load range;
• second valve means disposed in said second separate passage for permitting said engine coolant leaving said engine to flow through said second separate passage when said engine coolant is at temperatures higher than a second predetermined temperature higher than said first predetermined opening temperature;
• and
• bypass valve means for closing said bypass passage when said engine coolant is at a temperature between said first and second predetermined opening temperatures.

A cooling system for an internal combustion engine having a radiator for cooling engine coolant leaving an engine and a water pump for circulating said engine coolant through said engine, said cooling system comprising:

• an inlet radiator passage connecting said engine to said radiator, said inlet radiator passage being partly divided into first and second separate passages parallel to each other;
• an outlet radiator passage in which said water pump is disposed;
• a first bypass passage connecting an upstream part of said inlet radiator passage where said first and second separate passages are formed to said outlet radiator passage for allowing engine coolant leaving said engine to reenter into said engine while bypassing said radiator;
• a second bypass passage connecting said upstream part of said inlet radiator passage to said outlet radiator passage for allowing engine coolant leaving said engine to reenter into said engine while bypassing said radiator, said second bypass passage having a cross-sectional area smaller than that of said first bypass passage;
• first valve means disposed in said first separate passage of said inlet radiator passage for permitting said engine coolant leaving said engine to flow through said first separate passage when said engine coolant is at temperatures higher than a first predetermined opening temperature and said engine is not operated in low engine load range and interrupting said flow of engine coolant through said first separate passage when said engine is operated in said low engine load range;
• second valve means disposed in said second separate passage for permitting said engine coolant leaving said engine to flow through said second separate passage when said engine coolant is at temperatures higher than a second predetermined temperature higher than said first predetermined opening temperature;
• and
• bypass valve means coupled with said first valve means for closing said first bypass passage when said engine coolant is at a temperature between said first and second predetermined opening temperatures.