초록 ▼

A first loop contains engine coolant passageways (28, 30) and a first radiator (34). A second loop contains a first EGR cooler (48). A third loop contains a second EGR cooler (50), a second radiator (36), a charge air cooler (26LP), a first valve (66), and a second valve (64). Valve (64) apportions

A first loop contains engine coolant passageways (28, 30) and a first radiator (34). A second loop contains a first EGR cooler (48). A third loop contains a second EGR cooler (50), a second radiator (36), a charge air cooler (26LP), a first valve (66), and a second valve (64). Valve (64) apportions coolant flow entering an inlet (64A) to parallel flow paths, one including second radiator (36) and the other being a bypass around radiator (36). The apportioned flows merge into confluent flow to both an inlet of charge air cooler (26LP) and a first inlet (66B) of valve (66). Valve (66) has an outlet (66C) communicated to an inlet of second EGR cooler (50). The first condition of valve (66) closes a second inlet (66A) to coolant flowing toward both the second inlet (66A) and inlet (64A) while opening inlet (66B) to outlet (66C). The second condition of valve (66) opens second inlet (66A) to coolant flowing toward second inlet (66A) and inlet (64A) of the valve (64) while closing first inlet (66B) of valve (66) to outlet (66C) of valve (66).

대표청구항 ▼

1. An internal combustion engine comprising: engine structure comprising engine cylinders within which fuel is combusted to operate the engine and coolant passageways;an intake system for conveying air to the engine cylinders to support fuel combustion and comprising a charge air cooler for cooling

1. An internal combustion engine comprising: engine structure comprising engine cylinders within which fuel is combusted to operate the engine and coolant passageways;an intake system for conveying air to the engine cylinders to support fuel combustion and comprising a charge air cooler for cooling the air;an exhaust system for conveying combustion-created exhaust gas from the cylinders;an EGR system for recirculating some exhaust gas from the exhaust system successively through a first heat exchanger and a second heat exchanger to the intake system for entrainment with air being conveyed to the cylinders;a cooling system for circulating liquid coolant in multiple loops and comprising first and second radiators;a first of the loops comprising the coolant passageways where heat from the engine structure is transferred to coolant and the first radiator where heat in coolant that has passed through the coolant passageways is rejected;a second of the loops comprising one of the first and second heat exchangers; anda third of the loops comprising the other of the first and second heat exchangers, the second radiator, a charge air cooler, a first valve that is selectively operable to first and second conditions, and a second valve that is operable to selectively apportion coolant flow entering an inlet of the second valve to parallel flow paths, one of which includes the second radiator and another of which bypasses the second radiator, and which merge into confluent flow downstream of the second radiator to both an inlet of the charge air cooler and a first inlet of the first valve, the first valve having an outlet communicated an inlet of the other of the first and second heat exchangers;the first condition of the first valve closing a second inlet of the first valve to coolant flowing toward both the second inlet of the first valve and the first inlet of the second valve while opening the first inlet of the first valve to the outlet of the first valve, and the second condition of the first valve opening the second inlet of the first valve to coolant flowing toward the second inlet of the first valve and the first inlet of the second valve while closing the first inlet of the first valve to the outlet of the first valve. 2. An engine as set forth in claim 1 in which the one heat exchanger is the first heat exchanger, and the other heat exchanger is the second heat exchanger. 3. An engine as set forth in claim 2 in which the cooling system comprises a pump for circulating coolant through the loops, and in which a portion of the first loop that comprises the coolant passageways in the engine structure and a portion of the second loop that comprises the first heat exchanger are in parallel flow relationship between an outlet of the pump and an inlet of the first radiator. 4. An engine as set forth in claim 3 further including a temperature-controlled valve for disallowing coolant that has flowed through the portion of the first loop that comprises the coolant passageways in the engine structure and the portion of the second loop that comprises the first heat exchanger to flow to the first radiator until the coolant attains at least some minimum temperature. 5. An engine as set forth in claim 2 in which the cooling system comprises a pump for circulating coolant through the loops, and in which a portion of the first loop that comprises the coolant passageways in the engine structure and a portion of the second loop that comprises the first heat exchanger are in series flow relationship between an outlet of the pump and an inlet of the first radiator. 6. An engine as set forth in claim 5 in which a portion of the third loop includes the portion of the first loop that comprises the coolant passageways in the engine structure. 7. An engine as set forth in claim 6 further including a temperature-controlled valve for disallowing coolant that has flowed through both the portion of the first loop that comprises the coolant passageways in the engine structure and the portion of the second loop that comprises the first heat exchanger to flow to the first radiator until the coolant attains at least some minimum temperature. 8. An engine as set forth in claim 5 further including a temperature-controlled valve for disallowing coolant that has flowed through both the portion of the first loop that comprises the coolant passageways in the engine structure and the portion of the second loop that comprises the first heat exchanger to flow to the first radiator until the coolant attains at least some minimum temperature. 9. An engine as set forth in claim 2 in which the cooling system comprises a pump for circulating coolant through the loops, the temperature of coolant leaving an outlet of the pump is substantially equal to the temperature of coolant flowing from an outlet of the first radiator to an inlet of the pump, and the temperature of coolant flowing from the pump outlet to the second inlet of the first valve and the first inlet of the second valve is substantially equal to the temperature of coolant leaving the outlet of the pump. 10. An engine as set forth in claim 2 in which the cooling system comprises a pump for circulating coolant through the loops by pumping coolant from an outlet of the pump through the coolant passageways, and in which a portion of each loop comprises the coolant passageways. 11. An engine as set forth in claim 1 in which the intake system comprises at least one compressor for compressing air passing through the intake system, and the charge air cooler cools air that has been compressed by the at least one compressor. 12. An engine as set forth in claim 11 in which the charge air cooler cools air that has been compressed by a low-pressure compressor stage before further compression by a high-pressure stage. 13. A circuit for cooling both exhaust gas being recirculated through an EGR system of an internal combustion engine and charge air for supporting combustion in engine combustion chambers, the circuit comprising: a first loop comprising coolant passageways in engine structure where heat from the engine structure is transferred to coolant and a first radiator where heat in coolant that has passed through the coolant passageways is rejected;a second loop comprising a first EGR cooler; anda third loop comprising a second EGR cooler, a second radiator, a charge air cooler for cooling charge air entering the engine, a first valve that is selectively operable to first and second conditions, and a second valve that is operable to selectively apportion coolant flow entering an inlet of the second valve to parallel flow paths, one of which includes the second radiator and another of which bypasses the second radiator, and which merge into confluent flow downstream of the second radiator to convey coolant to both an inlet of the charge air cooler and a first inlet of the first valve, the first valve having an outlet communicated an inlet of the second EGR cooler;the first condition of the first valve closing a second inlet of the first valve to coolant flowing toward both the second inlet of the first valve and the first inlet of the second valve while opening the first inlet of the first valve to the outlet of the first valve, and the second condition of the first valve opening the second inlet of the first valve to coolant flowing toward the second inlet of the first valve and the first inlet of the second valve while closing the first inlet of the first valve to the outlet of the first valve. 14. A circuit as set forth in claim 13 comprising a pump for circulating coolant through the loops, and in which a portion of the first loop that comprises the coolant passageways in the engine structure and a portion of the second loop that comprises the first EGR cooler are in parallel flow relationship between an outlet of the pump and an inlet of the first radiator. 15. A circuit as set forth in claim 14 further including a temperature-controlled valve for disallowing coolant that has flowed through the portion of the first loop that comprises the coolant passageways in the engine structure and the portion of the second loop that comprises the first EGR cooler to flow to the first radiator until the coolant attains at least some minimum temperature. 16. A circuit as set forth in claim 13 comprises a pump for circulating coolant through the loops, and in which a portion of the first loop that comprises the coolant passageways in the engine structure and a portion of the second loop that comprises the first EGR cooler are in series flow relationship between an outlet of the pump and an inlet of the first radiator. 17. A circuit as set forth in claim 16 in which a portion of the third loop includes the portion of the first loop that comprises the coolant passageways in the engine structure. 18. A circuit as set forth in claim 17 further including a temperature-controlled valve for disallowing coolant that has flowed through both the portion of the first loop that comprises the coolant passageways in the engine structure and the portion of the second loop that comprises the first EGR cooler to flow to the first radiator until the coolant attains at least some minimum temperature. 19. A circuit as set forth in claim 16 further including a temperature-controlled valve for disallowing coolant that has flowed through both the portion of the first loop that comprises the coolant passageways in the engine structure and the portion of the second loop that comprises the first EGR cooler to flow to the first radiator until the coolant attains at least some minimum temperature. 20. A circuit as set forth in claim 13 comprising a pump for circulating coolant through the loops, the temperature of coolant leaving an outlet of the pump is substantially equal to the temperature of coolant flowing from an outlet of the first radiator to an inlet of the pump, and the temperature of coolant flowing from the pump outlet to the second inlet of the first valve and the first inlet of the second valve is substantially equal to the temperature of coolant leaving the outlet of the pump. 21. A circuit as set forth in claim 13 comprising a pump for circulating coolant through the loops by pumping coolant from an outlet of the pump through the coolant passageways, and in which a portion of each loop comprises the coolant passageways. 22. A circuit as set forth in claim 13 in which the charge air cooler cools air that has been compressed by a compressor in an intake system of the engine. 23. A circuit as set forth in claim 13 in which the charge air cooler cools air that has been compressed by a low-pressure compressor stage of a two-stage compressor before further compression by a high-pressure stage. 24. A method for cooling both exhaust gas being recirculated through an EGR system of an internal combustion engine and charge air for supporting combustion in engine combustion chambers, the method comprising: circulating liquid coolant in a first loop comprising coolant passageways in engine structure where heat from the engine structure is transferred to coolant and a first radiator where heat in coolant that has passed through the coolant passageways is rejected;circulating liquid coolant in a second loop comprising a first EGR cooler; andcirculating liquid coolant in a third loop comprising a second EGR cooler, a second radiator, a charge air cooler for cooling charge air entering the engine, a selectively operable first valve, and a second valve for selectively apportioning coolant flow entering an inlet of the second valve to parallel flow paths, one of which includes the second radiator and another of which bypasses the second radiator, and which merge into confluent flow downstream of the second radiator to convey coolant to both an inlet of the charge air cooler and a first inlet of the first valve, the first valve having an outlet communicated an inlet of the second EGR cooler;selectively operating the first valve to a first condition closing a second inlet of the first valve to coolant flowing toward both the second inlet of the first valve and the first inlet of the second valve while opening the first inlet of the first valve to the outlet of the first valve, and to the second condition opening the second inlet of the first valve to coolant flowing toward the second inlet of the first valve and the first inlet of the second valve while closing the first inlet of the first valve to the outlet of the first valve; andoperating the second valve to selectively apportion coolant flow entering the inlet of the second valve to the parallel flow paths.