Cooling apparatus for liquid-cooled internal combustion engine

• US 20020050251A1
• Filed: 09/17/2001
• Published: 05/02/2002
• Est. Priority Date: 09/18/2000
• Status: Active Grant

• Current Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ota, Masataka, Shinpo, Yoshikazu, Suzuki, Kazutaka, Takahashi, Eizo
• Granted Patent: US 6,530,347 B2
• Time in Patent Office: Days
• US Class Current: 123/41.1
• CPC Class Codes: F01P 2007/146 using valves
• CPC Class Codes: F01P 2037/02 starting
• CPC Class Codes: F01P 2060/04 Lubricant cooler
• CPC Class Codes: F01P 2060/045 for transmissions
• CPC Class Codes: F01P 2060/08 Cabin heater
• CPC Class Codes: F01P 7/048 using electrical drives
• CPC Class Codes: F01P 7/167 by adjusting the pre-set temperature according to engine parameters, e.g. engine load, engine speed

Abstract

Cooling water is circulated at small flow rate of 1 to 5 L/min between a bypass passage and an engine without circulating the cooling water in an oil cooler before the warming-up of the engine is completed. After the warming-up is completed, the cooling water is supplied to the oil cooler so that the engine cooling water temperature is maintained at 95° C. to 110° C. Consequently, the no local boiling of the cooling water in the engine occurs to prevent the engine from being deformed locally due to heat. Thus, the warming-up of the engine can be promoted while preventing the heat of the engine from being absorbed by the ATF through the cooling water. After the warming-up is completed, the fuel consumption can be improved by reducing the friction loss of the engine oil.

Claims

1. A cooling apparatus for a liquid-cooled internal combustion engine (10), comprising:

a radiator (20) that cools coolant discharged from the engine (10) and returns the cooled coolant to the engine (10);

a bypass passage (30) through which coolant discharged from the engine (10) bypasses the radiator (20) and returns to the engine (10); and

a heat exchanger (90) that exchanges heat between coolant discharged from the engine (10) and a working oil;

wherein when the temperature of the coolant discharged from the engine (10) is below a predetermined temperature, the flow rate of the coolant returned to the engine (10) is restricted to between 1 and 5 L/min, and the coolant discharged from the engine (10) is allowed to flow through the radiator (20) and the bypass passage (30) but not the heat exchanger (90); and

when the temperature of the coolant discharged from the engine is above the predetermined temperature, the coolant discharged from the engine is allowed to flow through the radiator (20), the bypass passage (30), and the heat exchanger (90).

2. A cooling apparatus for a liquid-cooled internal combustion engine (10) according to claim 1, wherein the heat exchanger (90) exchanges heat between working oil in a torque converter (80) for an automatic transmission and the coolant.

3. A cooling apparatus for a liquid-cooled internal combustion engine comprising:

a radiator (20) that cools coolant discharged from the engine (10) and returns the cooled coolant to the engine (10);

a bypass passage (30) through which the coolant discharged from the engine (10) bypasses the radiator (20) and returns to the engine (10); and

a heat exchanger (60) that exchanges heat between coolant discharged from the engine (10) and ambient air;

wherein before the engine is warmed-up of the engine, the flow rate of the coolant returned to the engine is restricted to between 1 and 5 L/min, and the coolant discharged from the engine (10) is allowed to flow through the radiator (20), the bypass passage (30) but not the heat exchanger (60); and

after the engine is warmed up, the coolant discharged by the engine (10) is allowed to flow through the radiator (20), the bypass passage (30) and the heat exchanger (60).

4. A cooling apparatus for a liquid-cooled internal combustion engine (10), comprising:

a radiator (20) that cools coolant discharged from the engine (10) and returns the cooled coolant engine;

a bypass passage (30) through which the coolant discharged from the engine (10) bypasses the radiator (20) and returns to the engine (10); and

a heat exchanger (90) that exchanges heat between coolant discharged from the engine (10) and a working oil;

wherein when the temperature of the coolant discharged from the engine is below a predetermined temperature, the flow rate of the coolant returned to the engine is restricted between 1 and 5 L/min, and the coolant discharged from the engine (10) is allowed to flow through only the radiator (20) and the bypass passage (30) but not the heat exchanger (90);

when the temperature of the coolant is above the predetermined temperature, the coolant discharged from the engine is allowed to flow through the radiator (20), the bypass passage (30), and the oil heat exchanger (90);

when the engine (10) is warmed up, the cooling liquid is circulated to the radiator (20) so that the temperature of the coolant is approximately in the range of 95°

C. to 110°

C.