Temperature-controlled variable speed water pump

• US 6,725,813 B1
• Filed: 03/03/2003
• Issued: 04/27/2004
• Est. Priority Date: 03/03/2003
• Status: Active Grant

• Current Assignee: BorgWarner Incorporated
• Original Assignee: BorgWarner Incorporated
• Inventors: Boyer, Rick L.
• Primary Examiner(s): Kamen, Noah P.
• Application Number:
  US10/378,120
• Time in Patent Office: 421 Days
• Field of Search: 123/41.44, 123/41.47
• US Class Current: 123/41.44
• CPC Class Codes: F01P 5/10 Pumping liquid coolant; Arrangements of coolant pumps
• CPC Class Codes: F01P 7/042 using fluid couplings couplings or clutches of this type per se F16D35/00
• CPC Class Codes: F01P 7/164 by varying pump speed
• CPC Class Codes: F04D 13/022 a coupling allowing slip, e.g. torque converter
• CPC Class Codes: F04D 15/0066 by changing the speed, e.g. of the driving engine

Abstract

A controllable viscous clutch that is integral to a water pump. The pump impeller is part of the output member of the clutch while the input is composed of a central drive shaft (attached to a pulley) and a clutch plate. A bimetallic control element located internally within the output member of a viscous type water pump to control the flow rate of engine coolent to an engine. The bimetallic control element reacts directly to sensed engine coolant temperature to control the amount of viscous fluid entering or exiting an operating chamber of the viscous type water pump. This enables the water pump to deliver low coolant flow during cold engine conditions and higher flow once the engine exceeds a predetermined temperature. This provides faster engine warm-up resulting in improved occupant comfort, fuel economy, and decreased tailpipe emissions.

Claims

1. A viscous type water pump used to control the flow rate of engine coolant within a coolant chamber coupled to an internal combustion engine, the water pump comprising:

an input member including a clutch plate coupled to a water pump shaft;

a belt operatively coupled to the internal combustion engine and said input member, said belt capable of causing the rotation of said input member around a central axis, said central axis defined along the length of said water pump shaft;

an output member rotatably coupled to said water pump shaft, said output member including a body and an impeller cover having a plurality of impeller blades contained within the coolant chamber, wherein said clutch plate is located within said body and said impeller cover;

a working chamber defined between said output member and said clutch plate;

an operating chamber fluidically coupled to said working chamber and defined between said output member and said clutch plate;

a reservoir plate rotatably coupled to said water pump shaft between said clutch plate and said impeller cover, said reservoir plate having a fill hole and a scavenge hole, said reservoir plate and said impeller cover defining a fluid reservoir;

a viscous fluid contained within said fluid reservoir; and

a bimetallic control element positioned in said fluid reservoir and coupled to said reservoir plate, said bimetallic control element capable of sensing engine coolant temperature through said impeller cover, and capable of movement between a first position and a second position as a function of said sensed engine coolant temperature to control the flow rate of said viscous fluid from said working chamber to said fluid reservoir.

2. The water pump of claim 1, wherein said first position is defined wherein said bimetallic control element is positioned such that said viscous fluid can flow from said working chamber through said scavenge hole and into said fluid reservoir.

3. The water pump of claim 1, wherein said second position is defined wherein said bimetallic control element covers said scavenge hole in said reservoir plate to substantially prevent the flow of said viscous fluid from said working chamber to said fluid reservoir.

4. The water pump of claim 1 further comprising a second bimetallic element positioned in said fluid reservoir and coupled to said reservoir plate, said bimetallic control element capable of sensing engine coolant temperature through said impeller cover, and capable of movement between a third position and a fourth position as a function of said sensed engine coolant temperature to control the flow rate of said viscous fluid from said fluid reservoir to said operating chamber.

5. The water pump of claim 4, wherein said first position is defined wherein said bimetallic control element is positioned such that said viscous fluid can flow from said working chamber through said scavenge hole and into said fluid reservoir and wherein said third position is defined wherein said second bimetallic element is positioned such that said viscous fluid cannot flow from said fluid chamber through said scavenge hole and into said operating chamber.

6. The water pump of claim 4, wherein said second position is defined wherein said bimetallic control element is positioned such that said viscous fluid cannot flow from said working chamber through said scavenge hole and into said fluid reservoir and wherein said fourth position is defined wherein said second bimetallic element is positioned such that said viscous fluid can flow from said fluid chamber through said scavenge hole and into said operating chamber.

7. The water pump of claim 4, wherein said bimetallic element and said second bimetallic element are integrally formed and comprise a single dual functional bimetallic element.

8. A method for precisely controlling the flow rate of engine coolant within a coolant chamber of a cooling system used to control the temperature of an internal combustion engine at a given engine speed, the method comprising:

(a) operatively coupling a viscous type water pump within the cooling system, the viscous coupling comprising;

an input member including a clutch plate coupled to a water pump shaft;

a belt operatively coupled to the internal combustion engine and said input member, said belt capable of causing the rotation of said input member around a central axis, said central axis defined along the length of said water pump shaft;

an output member rotatably coupled to said water pump shaft, said output member including a body and an impeller cover having a plurality of impeller blades contained within the coolant chamber, wherein said clutch plate is located within said body and said impeller cover;

a working chamber defined between said output member and said clutch plate;

an operating chamber fluidically coupled to said working chamber and defined between said output member and said clutch plate;

a reservoir plate rotatably coupled to said water pump shaft between said clutch plate and said impeller cover, said reservoir plate having a fill hole and a scavenge hole, said reservoir plate and said impeller cover defining a fluid reservoir;

a viscous fluid contained within said fluid reservoir;

a bimetallic control element positioned in said fluid reservoir and coupled to said reservoir plate;

(b) sensing an engine coolant temperature using said bimetallic control element; and

(c) controlling the amount of said viscous fluid contained within said working chamber as a function of said sensed engine coolant temperature at a given engine speed, wherein the amount of viscous fluid contained in said working chamber controls the amount of slippage created at a given engine speed between said input member and said output member to drive said output member.

9. The method of claim 8, wherein (c) controlling the amount of said viscous fluid contained within said working chamber comprises:

(c) controlling the relative positioning of said bimetallic control element between a first position and a second position as a function of said sensed engine coolant temperature, wherein said first position maximizes the accumulation of said viscous fluid within said operating chamber and wherein said second position minimizes the accumulation of said viscous fluid within said working chamber.

10. The method of claim 9, wherein said bimetallic control element is in said first position when the temperature of said engine coolant as sensed by said bimetallic control element is less than a predetermined engine coolant temperature.

11. The method of claim 10, wherein said bimetallic control element uncovers said scavenge hole in said first position.

12. The method of claim 10, wherein said bimetallic control element covers said fill hole in said first position.

13. The method of claim 10, wherein said bimetallic control element uncovers said scavenge hole and covers said fill hole in said first position.

14. The method of claim 9, wherein the viscous clutch further comprises a second bimetallic element positioned in said fluid reservoir and coupled to said reservoir plate.

15. The method of claim 14, wherein (c) controlling the amount of said viscous fluid contained within said working chamber comprises:

(c) controlling the relative positioning of said bimetallic element between a first position and a second position, said first position defined such that said bimetallic element uncovers said scavenge hole and wherein said second position defined such that said bimetallic element covers said scavenge hole; and

controlling the relative positioning of said second bimetallic element between a third position and a fourth position, wherein said third position is defined such that said second bimetallic element is covering said fill hole and wherein said fourth position is defined such that said second bimetallic element is uncovering said fill hole.

16. The method of claim 15, wherein said bimetallic element is positioned in said first position and said second bimetallic element is positioned in said third position when the temperature of said engine coolant as sensed by said is less than a predetermined engine coolant temperature.

17. The method of claim 15, wherein said bimetallic element is positioned in said second position when said second bimetallic element is positioned in said fourth position when the temperature of said engine coolant as sensed by said is greater than a predetermined engine coolant temperature.

18. The method of claim 9, wherein said bimetallic control element is in said second position when the temperature of said engine coolant as sensed by said is greater than a predetermined engine coolant temperature.

19. The method of claim 18, wherein said bimetallic control element covers said scavenge hole in said second position.

20. The method of claim 18, wherein said bimetallic control element uncovers said fill hole in said second position.

21. The method of claim 18, wherein said bimetallic control element covers said scavenge hole and uncovers said fill hole in said second position.

22. The method of claim 8, wherein (b) sensing an engine coolant temperature using said bimetallic control element comprising sensing engine coolant temperature by way of conduction through said impeller cover.

23. A viscous type water pump used to control the flow rate of engine coolant within a coolant chamber coupled to an internal combustion engine, the water pump comprising:

an input member including a clutch plate coupled to a water pump shaft;

a belt operatively coupled to the internal combustion engine and said input member, said belt capable of causing the rotation of said input member around a central axis, said central axis defined along the length of said water pump shaft;

an output member rotatably coupled to said water pump shaft, said output member including a body and an impeller cover having a plurality of impeller blades contained within the coolant chamber, wherein said clutch plate is located within said body and said impeller cover;

a working chamber defined between said output member and said clutch plate;

an operating chamber fluidically coupled to said working chamber and defined between said output member and said clutch plate;

a reservoir plate rotatably coupled to said water pump shaft between said clutch plate and said impeller cover, said reservoir plate having a fill hole and a scavenge hole, said reservoir plate and said impeller cover defining a fluid reservoir;

a viscous fluid contained within said fluid reservoir; and

a bimetallic control element positioned in said fluid reservoir and coupled to said reservoir plate, said bimetallic control element capable of sensing engine coolant temperature through said impeller cover, and capable of movement between an first position to a second position as a function of said sensed engine coolant temperature to control the flow of viscous fluid from said fluid reservoir through said fill hole and into said operating chamber.

24. The water pump of claim 23, wherein said first position is defined wherein said bimetallic control element is positioned such that said viscous fluid can flow from said fluid reservoir through said fill hole and into said operating chamber.

25. The water pump of claim 23, wherein said second position is defined wherein said bimetallic control element covers said fill hole in said reservoir plate to substantially prevent the flow of said viscous fluid from said fluid reservoir to said operating chamber.

26. A viscous type water pump used to control the flow rate of engine coolant within a coolant chamber coupled to an internal combustion engine, the water pump comprising:

an input member including a clutch plate coupled to a water pump shaft;

a belt operatively coupled to the internal combustion engine and said input member, said belt capable of causing the rotation of said input member around a central axis, said central axis defined along the length of said water pump shaft;

an output member rotatably coupled to said water pump shaft, said output member including a body and an impeller cover having a plurality of impeller blades contained within the coolant chamber, wherein said clutch plate is located within said body and said impeller cover;

a working chamber defined between said output member and said clutch plate;

an operating chamber fluidically coupled to said working chamber and defined between said output member and said clutch plate;

a reservoir plate rotatably coupled to said water pump shaft between said clutch plate and said impeller cover, said reservoir plate having a fill hole and a scavenge hole, said reservoir plate and said impeller cover defining a fluid reservoir;

a viscous fluid contained within said fluid reservoir; and

a bimetallic control element positioned in said fluid reservoir and coupled to said reservoir plate, said bimetallic control element capable of sensing engine coolant temperature through said impeller cover, and capable of movement between an first position to a second position as a function of said sensed engine coolant temperature to control the flow rate of said viscous fluid from said fluid reservoir to said operating chamber and to control the flow rate of fluid from said working chamber to said fluid reservoir.

27. The water pump of claim 26, wherein said first position is defined wherein a first portion of said bimetallic control element is positioned such that said viscous fluid can flow from said working chamber through said scavenge hole and into said fluid reservoir and wherein a second portion of said bimetallic control element covers said fill hole in said reservoir plate to substantially prevent the flow of said viscous fluid from said fluid reservoir to said operating chamber.

28. The water pump of claim 26, wherein said second position is defined wherein said bimetallic control element covers said scavenge hole in said reservoir plate to substantially prevent the flow of said viscous fluid from said working chamber to said fluid reservoir and wherein a second portion of said bimetallic control element is positioned such that said viscous fluid can flow from said fluid reservoir through said fill hole and into said operating chamber.