Two loop engine coolant system

• US 4,325,219 A
• Filed: 12/31/1979
• Issued: 04/20/1982
• Est. Priority Date: 12/31/1979
• Status: Expired due to Term

• Current Assignee: Cummins Engine Company Incorporated (Cummins Incorporated), Komatsu Ltd.
• Original Assignee: Cummins Engine Company Incorporated (Cummins Incorporated), Komatsu Ltd.
• Inventors: Stang, John H., Yamaguchi, Hiromasa
• Primary Examiner(s): Koczo, Jr., Michael
• Application Number:
  US06/108,821
• Time in Patent Office: 841 Days
• Field of Search: 60/599, 123/563
• US Class Current: 60/599
• CPC Class Codes: F01P 7/165 characterised by systems with two or more loops
• CPC Class Codes: F02B 29/0443 Layout of the coolant or refrigerant circuit
• CPC Class Codes: F02B 29/0493 Controlling the air charge temperature
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

This disclosure relates to a coolant system for an internal combustion engine including a turbocharger and an aftercooler. The coolant system comprises an engine loop and an aftercooler loop both loops utilizing a single pump. The engine loop includes the pump, the engine block and head, a first radiator, and a radiator bypass branch. The aftercooler loop includes the pump, the aftercooler, a second radiator, and a radiator bypass branch. Each loop further includes a temperature responsive flow control thermostat for regulating the coolant flow through the associated radiator and/or bypass branch. The thermostat in the aftercooler loop is mounted in the coolant intake line leading to the aftercooler, but it responds to the temperature of the coolant leaving the aftercooler.

Claims

1. A coolant system for an internal combustion engine including an aftercooler for cooling the intake air flowing into the engine, said aftercooler having a coolant intake and a coolant outlet, and said engine including a block and a head, said coolant system comprising an engine loop and an aftercooler loop, a pump having an output, both of said loops including said pump, said engine loop including said pump, the engine block and head, a first radiator, and a first radiator bypass, said aftercooler loop including said pump, said intake of the aftercooler being connected to said output of said pump, a second radiator and a second radiator bypass connected to said inlet of said aftercooler, each of said loops further including a temperature responsive flow control thermostat for regulating the coolant flow through the associated radiator and said bypass, said thermostat in said aftercooler loop including a sensor located in said coolant outlet to sense the temperature of the coolant leaving said aftercooler.

2. Apparatus as in claim 1, wherein said second radiator and said second radiator bypass are connected in parallel and are connected between the output of said pump and said coolant intake of said aftercooler.

3. Apparatus as in claim 2, wherein said thermostat of said aftercooler loop is connected between said coolant intake of said aftercooler and said parallel connection of said second radiator and said second radiator bypass.

4. Apparatus as in claim 2, wherein said thermostat of said aftercooler loop is connected between said output of said pump, said parallel connection of said second radiator and said second radiator bypass.

5. Apparatus as in claim 1, wherein said thermostat of said engine loop includes temperature responsive means for switching in a preset temperature range, and said thermostat of said aftercooler loop includes temperature responsive means for switching in a preset temperature range that is lower than said temperature range of said thermostat of said engine loop.

6. Apparatus as in claim 1, and further including a coolant flow passage in said aftercooler loop, said passage being in parallel with and upstream of said second radiator and said second radiator bypass, and a third thermostat connected in said passage, each of said thermostats switching at a preset temperature range, and said range for said third thermostat being lower than said ranges for the other of said thermostats.

7. Apparatus as in claim 1, wherein said engine loop includes flow passages and said intercooler loop includes flow passages, and the flow capacity of said passages of said engine loop are substantially greater than the flow capacity of said passages of said aftercooler loop.

8. A coolant system of an internal combustion engine including an aftercooler, said system comprising a coolant pump, coolant flow lines connecting the intake and outlet of said pump with the intake and outlet of said aftercooler, whereby the coolant is pumped in a loop including the aftercooler, the pump, and said flow lines, one of said lines being formed by a radiator branch and by a bypass branch in parallel with said radiator branch, said system further including a temperature responsive flow control thermostat connected to said branches at said intake of said aftercooler for regulating the coolant flow through said radiator branch and said bypass branch, said thermostat including a sensor located to respond to the temperature of the coolant adjacent the outlet of said aftercooler.

9. A coolant system as in claim 8, wherein said branches are in said line between said pump outlet and said aftercooler intake.

10. A coolant system for an internal combustion engine having an aftercooler, the engine and the aftercooler having coolant flow passages therein, said coolant system comprising:

(a) a coolant pump including an intake and outlet,

(b) a first line connecting said pump outlet with the engine passages,

(c) a second line connecting the engine passage with the said pump intake, said second line comprising first and second branches, a first heat exchanger connected in said first branch, first valve means connected in said second line for controlling the flow of coolant through said first and second branches, said first valve means responding to the coolant temperature in said second line and directing coolant through said first branch at elevated temperatures and directing coolant through said second branch at reduced temperatures,

(d) a third line connecting said pump intake with an outlet end of said aftercooler, and

(e) a fourth line connecting said pump outlet with the inlet end of said aftercooler, said fourth line comprising third and fourth branches, a second heat exchanger connected in said third branch, second valve means connected in said fourth line for controlling the flow of coolant through said third and fourth branches to said inlet end of said aftercooler, said second valve means including sensor means responding to the coolant temperature leaving said outlet end of said aftercooler and directing coolant flow through said third branch at elevated temperatures and directing coolant flow through said fourth branch at reduced temperatures.

11. An internal combustion engine comprising a block and head having combustion chambers and coolant passages therein, a pump, a first radiator and a first radiator bypass, flow lines connecting said pump with said passages, said radiator and said radiator bypass, a turbocharger connected to supply intake air to the combustion chambers of said engine, first temperature responsive flow control means connected to regulate the flow of coolant through said first radiator and said first radiator bypass, an aftercooler mounted in the intake air flow path between said turbocharger and said chambers, coolant flow passages in said aftercooler and said passages including an intake and an outlet, a second radiator and a second radiator bypass, flow lines connecting said pump with said aftercooler, said second radiator, and said second radiator bypass, and second temperature responsive flow control means connected in said intake to regulate the flow of coolant through said second radiator and said second radiator bypass, said second flow control means including sensor means connected in said outlet and responsive to the temperature of the coolant leaving said aftercooler.