Claims:We Claim

1. A circuit (10) for regulating a temperature of charge air supplied from a charge air cooler (12) to an engine (14) based on an engine exhaust gas temperature, the circuit (10) comprising:
the charge air cooler (12) comprising an upstream end (16) and a downstream end (18), the upstream end (16) of said charge air cooler (12) in flow communication with a compressor (20) of a turbocharger (22), the downstream end (18) of said charge air cooler (12) in flow communication with an inlet manifold (24) of the engine (14);
a first engine cooling circuit (25) in flow communication between said engine (14) and an inlet (26) of a high temperature cooler (28), the first engine cooling circuit (25) adapted to supply high temperature coolant from said engine (14) to said high temperature cooler (28); characterized in that
a bypass flow duct (30) comprising an upstream end (32) and a downstream end (34), the upstream end (32) of said bypass flow duct (30) in flow communication with said first engine cooling circuit (25), the downstream end (34) of said bypass flow duct (30) in flow communication with a first inlet port (36) of a first three-way valve (38), the bypass flow duct (30) adapted to channel high temperature coolant from the first engine cooling circuit (25) to the first inlet port (36) of said first three-way valve (38);
an outlet port (40) of said first three-way valve (38) in flow communication with an inlet port (42) of an electric feed pump (44), the outlet port (40) of said first three-way valve (38) adapted to channel high temperature coolant that is delivered to the first inlet port (36) of said first three-way valve (38) from the bypass flow duct (30) to the inlet port (42) of said electric feed pump (44);
an outlet port (46) of said electric feed pump (44) in flow communication with an inlet port (43) of said charge air cooler (12), the outlet port (46) of said electric feed pump (44) adapted to channel high temperature coolant that is delivered to the inlet port (42) of said electric feed pump (44) to the inlet port (43) of said charge air cooler (12);
an outlet port (45) of said charge air cooler (12) in flow communication with an inlet port (50) of a second three-way valve (52), the outlet port (45) of said charge air cooler (12) adapted to channel high temperature coolant from the charge air cooler (12) to the first inlet port (50) of said second three-way valve (52); and
a first outlet port (54) of said second three-way valve (52) in flow communication with a second engine cooling circuit (55), said second engine cooling circuit (55) in flow communication between an outlet (58) of said high temperature cooler (28) and an inlet (60) of a fuel circulation pump (62), the first outlet port (54) of said second three-way valve (52) adapted to channel high temperature coolant that is delivered to the first inlet port (50) of said second three-way valve (52) from the outlet port (45) of said charge air cooler (12) to the second engine cooling circuit (55).

2. The circuit (10) for regulating the temperature of charge air supplied from the charge air cooler (12) to an engine (14) based on the engine exhaust gas temperature in accordance with Claim 1, further comprising a first low temperature coolant flow path (64) comprising an upstream end and a downstream end, the upstream end of said first low temperature coolant flow path (64) in flow communication with an outlet port of a low temperature cooler (66), the downstream end of said first low temperature coolant flow path (64) in flow communication with a second inlet port (68) of the first three-way valve (38), the first low temperature coolant flow path (64) adapted to channel low temperature coolant from the outlet port of the low temperature cooler (66) to the second inlet port (68) of said first three-way valve (38).

3. The circuit (10) for regulating the temperature of charge air supplied from the charge air cooler (12) to the engine (14) based on the engine exhaust gas temperature in accordance with Claim 2, further comprising the outlet port (40) of said first three-way valve (38) in flow communication with the inlet port (42) of the electric feed pump (44), the outlet port (40) of said first three-way valve (38) adapted to channel low temperature coolant that is delivered to the second inlet port (68) of said first three-way valve (38) from the low temperature cooler (66) to the inlet port (42) of said electric feed pump (12).

4. The circuit (10) for regulating the temperature of charge air supplied from the charge air cooler (12) to the engine (14) based on the engine exhaust gas temperature in accordance with Claim 3, further comprising the outlet port (46) of the electric feed pump (44) in flow communication with the inlet port (43) of said charge air cooler (12), the outlet port (46) of said electric feed pump (44) adapted to channel low temperature coolant that is delivered to the inlet port (42) of said electric feed pump (44) to the inlet port (43) of said charge air cooler (12).

5. The circuit (10) for regulating the temperature of charge air supplied from the charge air cooler (12) to the engine (14) based on the engine exhaust gas temperature in accordance with Claim 4, further comprising the outlet port (45) of said charge air cooler (12) in flow communication with the inlet port (50) of the second three-way valve (52), the outlet port (45) of said charge air cooler (12) adapted to channel low temperature coolant from the charge air cooler (12) to the inlet port (50) of said second three-way valve (52).

6. The circuit (10) for regulating the temperature of charge air supplied from the charge air cooler (12) to the engine (14) based on the engine exhaust gas temperature in accordance with Claim 5, further comprising a second outlet port (70) of said second three-way valve (52) in flow communication with an inlet port of the low temperature cooler (66), the second outlet port (70) of said second three-way valve (52) adapted to channel low temperature coolant that is delivered from the outlet port (45) of said charge air cooler (12) to the inlet port of the low temperature cooler (66).

7. The circuit (10) for regulating the temperature of charge air supplied from the charge air cooler (12) to the engine (14) based on the engine exhaust gas temperature in accordance with Claim 1, further comprising an engine control unit (75) in electronic communication with the first three-way valve (38) via a first control flow path (80), the engine control unit (75) adapted to control an opening of the first inlet port (36) of said first three-way valve (38), thereby channeling high temperature coolant from the bypass flow duct (30) to the inlet port (42) of said electric feed pump (44) when an exhaust temperature of the engine (14) is lower than a threshold temperature value that is defined by a user.

8. The circuit (10) for regulating the temperature of charge air supplied from the charge air cooler (12) to the engine (14) based on the engine exhaust gas temperature in accordance with Claim 7, wherein the engine control unit (75) is adapted to control an opening of the second inlet port (68) of said first three-way valve (38), thereby channeling low temperature coolant from the outlet port of the low temperature cooler (66) to the inlet port (42) of said electric feed pump (44) when an exhaust gas temperature of the engine (14) is greater than a threshold temperature value that is defined by the user.

9. The circuit (10) for regulating the temperature of charge air supplied from the charge air cooler (12) to the engine (14) based on the engine exhaust gas temperature in accordance with Claim 1, further comprising an engine control unit (75) in electronic communication with the second three-way valve (52), the engine control unit (75) adapted to control an opening of the first outlet port (54) of said second three-way valve (52), thereby channeling high temperature coolant from the charge air cooler (12) to the second engine cooling circuit (55) when an exhaust gas temperature of the engine is lower than a threshold temperature value that is defined by a user.

10. The circuit (10) for regulating the temperature of charge air supplied from the charge air cooler (12) to the engine (14) based on an engine exhaust gas temperature in accordance with Claim 9, wherein the engine control unit (75) is adapted to control an opening of the second outlet port (70) of said second three-way valve (52), thereby channeling low temperature coolant from the charge air cooler (12) to the inlet port of the low temperature cooler (66) when an exhaust gas temperature of the engine is higher than the threshold temperature value that is defined by the user.

11. A circuit (10) for regulating a temperature of charge air supplied from a charge air cooler (12) to an engine (14) based on an engine exhaust gas temperature, the circuit (10) comprising:
a charge air cooler (12) comprising an upstream end (16) and a downstream end (18), the upstream end (16) of said charge air cooler (12) in flow communication with a compressor (20) of a turbocharger (22), the downstream end (18) of said charge air cooler (12) in flow communication with an inlet manifold (24) of an engine (14);
a first engine cooling circuit (25) in flow communication between said engine (14) and an inlet (26) of a high temperature cooler (28), the first engine cooling circuit (25) adapted to deliver high temperature coolant from said engine (14) to said high temperature cooler (28); characterized in that
a bypass flow duct (30) in flow communication with said first engine cooling circuit (25), and adapted to channel high temperature coolant from said first engine cooling circuit (25) to an inlet port (43) of said charge air cooler (12); and
an outlet port (45) of said charge air cooler (12) in flow communication with a second engine cooling circuit (55) and adapted to channel high temperature coolant from the outlet port (45) of said charge air cooler (12) to the second engine cooling circuit (55).
, Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] This invention relates to an engine coolant circuit and a low temperature coolant circuit for exchanging heat with a charge air cooler, and more specifically for regulating a temperature of air supplied from the charge air cooler to an engine based on an engine exhaust gas temperature.

Background of the invention
[0002] DE 3200684 A1 describes a liquid-cooled internal combustion engine with supercharging. A supercharged, liquid-cooled internal combustion engine with a charge air cooler is described. The charge air cooler through which liquid ducts pass and internal combustion engine coolant flows, has a control valve which can be actuated as a function of a characteristic operating variable of the internal combustion engine. The liquid ducts of the charge air cooler can be shut off from the coolant circuit of the internal combustion engine as necessary. After shutting off, the liquid enclosed in the charge air cooler reaches the charge air temperature, which is low at partial load, relatively quickly, thereby ensuring an adequate charge air cooling at the start of an acceleration sequence.

Brief description of the accompanying drawing
[0003] Figure 1 depicts a schematic drawing of an engine coolant circuit and a low temperature coolant circuit for exchanging heat with a charge air cooler in one embodiment of the invention.

Detailed description of the embodiments
[0004] A circuit 10 for regulating a temperature of charge air supplied from a charge air cooler 12 to an engine 14 based on an engine exhaust gas temperature is described. The circuit 10 comprises a charge air cooler 12 comprising an upstream end 16 and a downstream end 18. The upstream end 16 of the charge air cooler 12 is in flow communication with a compressor 20 of a turbocharger 22. The downstream end 18 of the charge air cooler 12 is in flow communication with an inlet manifold 24 of an engine 14. A first engine cooling circuit 25 is in flow communication between the engine 14 and an inlet 26 of a high temperature cooler 28. The first engine cooling circuit 25 is adapted to supply high temperature coolant from the engine 14 to the high temperature cooler 28. A bypass flow duct 30 comprises an upstream end 32 and a downstream end 34. The upstream end 32 of the bypass flow duct 30 is in flow communication with the first engine cooling circuit 25. The downstream end 34 of the bypass flow duct 30 is in flow communication with a first inlet port 36 of a first three-way valve 38. The bypass flow duct 30 is adapted to channel high temperature coolant from the first engine cooling circuit 25 to the first inlet port 36 of the first three-way valve 38. An outlet port 40 of the first three-way valve 38 is in flow communication with an inlet port 42 of an electric feed pump 44. The outlet port 40 of the first three-way valve 38 is adapted to channel high temperature coolant that is delivered to the first inlet port 36 of the first three-way valve 38 from the bypass flow duct 30 to the inlet port 42 of the electric feed pump 44. An outlet port 46 of the electric feed pump 44 is in flow communication with an inlet port 43 of the charge air cooler 12. The outlet port 46 of the electric feed pump 44 is adapted to channel high temperature coolant that is delivered to the inlet port 42 of the electric feed pump 44 to the inlet port 43 of the charge air cooler 12. An outlet port 45 of the charge air cooler 12 is in flow communication with an inlet port 50 of a second three-way valve 52. The outlet port 45 of the charge air cooler 12 is adapted to channel high temperature coolant from the charge air cooler 12 to the inlet port 50 of the second three-way valve 52. A first outlet port 54 of the second three-way valve 52 is in flow communication with a second engine cooling circuit 55. The second engine cooling circuit 55 is in flow communication between an outlet 58 of the high temperature cooler 28 and an inlet 60 of a fuel circulation pump 62. The first outlet port 54 of the second three-way valve 52 is adapted to channel high temperature coolant that is delivered to the first inlet port 50 of the second three-way valve 52 from the outlet port 45 of the charge air cooler 12 to the second engine cooling circuit 55.

[0005] Figure 1 depicts a schematic drawing of an engine coolant circuit and a low temperature coolant circuit for exchanging heat with a charge air cooler 12 in one embodiment of the invention. In an exemplary embodiment, a circuit 10 for regulating a temperature of charge air supplied from the charge air cooler 12 to an engine 14 based on an engine exhaust gas temperature is described. The circuit 10 comprises a charge air cooler 12 that comprises an upstream end 16 and a downstream end 18. The upstream end 16 of the charge air cooler 12 is in flow communication with a compressor 20 of a turbocharger 22 and received compressed air from the turbocharger 22. The downstream end 18 of the charge air cooler 12 is in flow communication with an inlet manifold 24 of an engine 14 and delivers the compressed air that is received from the turbocharger 22 to the inlet manifold 24 of the engine 14. A first engine cooling circuit 25 is in flow communication between an outlet of cooling jackets of the engine 14 and an inlet 26 of a high temperature cooler 28. The first engine cooling circuit 25 is adapted to supply high temperature coolant from the outlet of the cooling jackets of the engine 14 to the high temperature cooler 28 via a thermostat 19.

[0006] A bypass flow duct 30 comprises an upstream end 32 and a downstream end 34. The upstream end 32 of the bypass flow duct 30 is in flow communication with the first engine cooling circuit 25 that is in flow communication between an outlet of the cooling jackets of the engine 14 and an inlet 26 of the high temperature cooler 28. The downstream end 34 of the bypass flow duct 30 is in flow communication with a first inlet port 36 of a first three-way valve 38. More specifically, the bypass flow duct 30 is adapted to channel high temperature coolant from the first engine cooling circuit 25 to the first inlet port 36 of the first three-way valve 38. An outlet port 40 of the first three-way valve 38 is in flow communication with an inlet port 42 of an electric feed pump 44. The outlet port 40 of the first three-way valve 38 is adapted to channel high temperature coolant that is delivered to the first inlet port 36 of the first three-way valve 38 from the bypass flow duct 30 to the inlet port 42 of the electric feed pump 44. Correspondingly, an outlet port 46 of the electric feed pump 44 is in flow communication with an inlet port 43 of the charge air cooler 12, and is adapted to deliver high temperature coolant that is delivered to the inlet port 42 of the electric feed pump 44 to the inlet port 43 of the charge air cooler 12. An outlet port 45 of the charge air cooler 12 is in flow communication with a first inlet port 50 of a second three-way valve 52. More specifically, the inlet port 50 of the second three-way valve 52 is adapted to receive the coolant that is used to heat the charge air that flows from the compressor 20 of the turbocharger 22 to the inlet manifold 24 of the engine 14 via the charge air cooler 12. A first outlet port 54 of the second three-way valve 52 is in flow communication with a second engine cooling circuit 55, and is adapted to deliver the high temperature coolant from the inlet port 50 of the second-three way valve 52 to the second cooling circuit 55. More specifically, the second engine cooling circuit 55 is in flow communication between an outlet 58 of the high temperature cooler 28 and an inlet 60 of a fuel circulation pump 62, and delivers high temperature coolant to the inlet 60 of the fuel circulation pump 62 that is further channeled into the cooling jackets of the engine 14. Therefore, the first outlet port 54 of the second three-way valve 38 is adapted to channel high temperature coolant that is delivered to the first inlet port 40 of the second three-way valve 38 from the outlet port 45 of the charge air cooler 12 to the second engine cooling circuit 55.

[0007] In an exemplary embodiment, the circuit 10 for regulating a temperature of charge air supplied from the charge air cooler 12 to the engine 14 based on an engine exhaust gas temperature further comprises a first low temperature coolant flow path 64 comprising an upstream end and a downstream end. The upstream end of the first low temperature coolant flow path 64 is in flow communication with an outlet port of a low temperature cooler 66 and is adapted to receive the low temperature coolant from the outlet port of the low temperature cooler 66. The downstream end of the first low temperature coolant flow path 64 is in flow communication with a second inlet port 68 of the first three-way valve 38. The first low temperature coolant flow path 64 is adapted to channel low temperature coolant from the outlet port of the low temperature cooler 66 to the second inlet port 68 of the first three-way valve 38. Once the low temperature coolant from the outlet port of the low temperature cooler 66 is channeled to the second inlet port 68 of the first three-way valve 38, the outlet port 40 of the first three-way valve 38 is in flow communication with an inlet port 42 of the electric feed pump 44. More specifically, the electric feed pump 44 is employed to circulate the high temperature coolant from the first cooling circuit 25 to the charge air cooler 12 and the low temperature coolant from the low temperature cooler 66 to the charge air cooler 12. Therefore, the outlet port 40 of the first three-way valve 38 is adapted to channel low temperature coolant that is delivered to the second inlet port 68 of the first three-way valve 38 from the low temperature cooler 66 to the inlet port 42 of the electric feed pump 44.

[0008] Once the low temperature coolant is delivered to the inlet port 42 of the electric feed pump 44, the electric feed pump 44 delivers the low temperature coolant to the inlet port 43 of the charge air cooler 12. More specifically, the outlet port 46 of the electric feed pump 44 is in flow communication with the inlet port 43 of the charge air cooler 12 and delivers the low temperature coolant to the inlet port 43 of the charge air cooler 12. In an exemplary embodiment, an outlet port 45 of the charge air cooler 12 is in flow communication with the inlet port 50 of the second three-way valve 52. The outlet port 45 of the charge air cooler 12 is adapted to channel low temperature coolant to the inlet port 50 of the second three-way valve 52 after the compressed air exiting from the compressor 20 of the turbocharger 22 has been cooled in the charge air cooler 12. In an exemplary embodiment, a second outlet port 70 of the second three-way valve 52 is in flow communication with an inlet port of the low temperature cooler 66. More specifically, the second outlet port 70 of the second three-way valve 52 is adapted to channel low temperature coolant that is delivered from the outlet port 45 of the charge air cooler 12 to the inlet port of the low temperature cooler 66.

[0009] In an exemplary embodiment, an engine control unit 75 is in electronic communication with the first three-way valve 38 via a control flow path 80. The engine control unit 75 is adapted to control an opening the first inlet port 36 of the first three-way valve 38, thereby channeling high temperature coolant from the bypass flow duct 30 to the inlet port 42 of the electric feed pump 44 via the first inlet port 36 of the first three-way valve 38 when an exhaust gas temperature of the engine 14 is lower than a threshold temperature value that is defined by a user. Moreover, the engine control unit 75 is adapted to control an opening of. the second inlet port 68 of the first three-way valve 38, thereby channeling low temperature coolant from the outlet port of the low temperature cooler 66 to the inlet port 42 of the electric feed pump 44 via the second inlet port 68 of the first three-way valve 38 when an exhaust gas temperature of the engine 14 is higher than a threshold temperature value that is defined by the user. The rationale will be provided in the working of the charge air cooler 12 in the subsequent sections of this manuscript.

[0010] In an exemplary embodiment, the engine control unit 75 is in electronic communication with the second three-way valve 52 via a control flow path 90. The engine control unit 75 is adapted to control an opening of the first outlet port 54 of the second three-way valve 52, thereby channeling high temperature coolant from the charge air cooler 12 to the second engine cooling circuit 55 when an exhaust gas temperature of the engine 14 is lower than a threshold temperature value that is defined by a user. Moreover, the engine control unit 75 is adapted to control an opening of the second outlet port 70 of the second three-way valve 52, thereby channeling low temperature coolant from the charge air cooler 12 to the inlet port of the low temperature cooler 66 via the second outlet port 70 of the second three-way valve 52 when an exhaust gas temperature of the engine 14 is higher than a threshold temperature value that is defined by the user. The rationale will be provided in the working of the charge air cooler 12 in the subsequent sections of this manuscript.

[0011] A working of the charge air cooler 12 is herein described as an example. When the temperature of the exhaust gas that exits from the engine 14 is below a threshold temperature that is defined by a user, the exhaust gas sensor transmits a signal to the engine control unit 75. The engine control unit 75 therein facilitates the opening of the first inlet port 36 and closing the second inlet port 68 of the first three-way valve 38, thereby channeling high temperature coolant that flows from the outlet of the engine 14 to the inlet 26 of the high temperature cooler 28 through the bypass flow path 30 to the first three-way valve 38. The high temperature coolant that flows through the bypass flow path 30 is channeled to the inlet port 42 of the electric feed pump 44 via the first inlet port 36 of the first three way valve 38, and via the outlet port 40 of the first three-way valve 38. The high temperature coolant is therein circulated by the electric feed pump 44 to the inlet port 43 of the charge air cooler 12. The temperature of the compressed air that is delivered from the compressor 20 of the turbocharger 22 to the charge air cooler 12 is increased by the high temperature coolant that is circulated by the electric feed pump 44 to the inlet port 43 of the charge air cooler 12. Once the temperature of the compressed air that is delivered from the compressor 20 of the turbocharger 22 to the charge air cooler 12 is increased by the high temperature coolant, the high temperature compressed air is delivered to the inlet manifold 24 of the engine 14 for combustion in the engine cylinder. Due to the increase in the temperature of the charge air that is delivered to the inlet manifold 24 of the engine 14, the temperature of the exhaust gas exiting the outlet manifold of the engine 14 may be effectively increased. The high temperature coolant from the charge air cooler 12 is delivered to the inlet port 50 of the second three-way valve 52. Therein, the engine control unit 75 controls the first outlet port 54 of the second three-way valve to open, and controls the second outlet port 70 of the second three-way valve 52 to close, thereby channeling high temperature coolant from the first outlet port 54 of the second three-way valve 52 to the second engine cooling circuit 55 that is in flow communication between the outlet of the high temperature cooler 28 and the inlet 60 of the fuel circulation pump 62.

[0012] When the temperature of the exhaust gas that exits from the engine 14 is above the threshold temperature that is defined by the user, the exhaust gas sensor transmits a signal to the engine control unit 75. The engine control unit 75 therein facilitates the opening of the second inlet port 68 and closing the first inlet port 34 of the first three way valve 38, thereby channeling low temperature coolant from the outlet port of the low temperature cooler 66 to the second inlet port 68 of the first three-way valve 38. The low temperature coolant from the outlet port of the low temperature cooler 66 is channeled to the inlet port 42 of the electric feed pump 44 via the second inlet port 68 of the first three-way valve 38, and via the outlet port 40 of the first three-way valve 38. The low temperature coolant is therein circulated by the electric feed pump 44 to the inlet port 43 of the charge air cooler 12. The temperature of the compressed air that is delivered from the compressor 20 of the turbocharger 22 to the charge air cooler 12 is decreased by the low temperature coolant that is circulated by the feed pump 44 to the inlet port 43 of the charge air cooler 12. Once the temperature of the compressed air that is delivered from the compressor 20 of the turbocharger 22 to the charge air cooler 12 is decreased by the low temperature coolant, the low temperature compressed air from the charge air cooler 12 is delivered to the inlet manifold 24 of the engine 14 for combustion in the engine cylinder. Due to the reduction in the temperature of the charge air that is delivered to the inlet manifold 24 of the engine 14, the temperature of the exhaust gas exiting the outlet manifold of the engine can be effectively decreased. The low temperature coolant from the charge air cooler 12 is supplied to the inlet port 50 of the second three-way valve 52. Therein, the engine control unit 75 controls the second outlet port 70 of the second three-way valve 52 to open, thereby channeling low temperature coolant to flow from the second outlet port 70 of the second three-way valve 52 to the inlet port of the low temperature cooler 66. Therefore, when the temperature of the exhaust gas that is channeled from the outlet manifold of the engine 14 is lower than a threshold temperature and required to be heated up, high temperature coolant is permitted to circulate from the first engine cooling circuit 25 to the charge air cooler 12 via the first three way valve 38, and back from the charge air cooler 12 to the second engine cooling circuit 55 via the second three-way valve 52. Similarly, when the temperature of the exhaust gas that is channeled from the outlet manifold of the engine 14 is higher than a threshold temperature and requires to be cooled down, low temperature coolant is permitted to circulate from the outlet port of the low temperature cooler 66 to the charge air cooler 12 via the first three way valve 38, and back from the charge air cooler 12 to the inlet port of the low temperature cooler 66 via the second three-way valve 52.

[0013] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.