Internal combustion engine cooling system and method of operation thereof

• US 4,539,942 A
• Filed: 10/18/1984
• Issued: 09/10/1985
• Est. Priority Date: 11/25/1983
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Yoshimura, Kunimasa, Kobayashi, Hideo, Kashiwagi, Takao, Mae, Hisao
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Application Number:
  US06/662,052
• Time in Patent Office: 327 Days
• Field of Search: 123/41.02, 123/41.08, 123/41.09, 123/41.1, 123/41.11, 123/41.12, 123/41.29, 123/41.44, 123/41.47, 123/41.49, 123/41.82 R
• US Class Current: 123/41.1
• CPC Class Codes: F01P 2003/027 Cooling cylinders and cylinder heads in parallel
• CPC Class Codes: F01P 2007/146 using valves
• CPC Class Codes: F01P 2025/32 Engine outcoming fluid temperature
• CPC Class Codes: F01P 2025/50 using two or more temperature sensors
• CPC Class Codes: F01P 2060/08 Cabin heater
• CPC Class Codes: F01P 7/08 by cutting in or out of pumps
• CPC Class Codes: F01P 7/165 characterised by systems with two or more loops
• CPC Class Codes: G05D 23/1934 each space being provided with one sensor acting on one or more control means
• CPC Class Codes: G05D 23/24 the sensing element having a resistance varying with temperature, e.g. a thermistor

Abstract

An engine has cylinder head and cylinder block cooling jackets. A control system controls a valve system to circulate fluid through a conduit system, the jackets and a radiator in various flow patterns. If the block jacket cooling fluid temperature is less than a warmup completion temperature, the control system establishes a combined conduit circuit including both the head and the block cooling jacket but not including the radiator, and makes a cooling fan system for the radiator blow relatively weakly. If the block jacket cooling fluid temperature is greater than the warmup completion temperature, then, if it is less than an overheating temperature higher than that, the control system establishes two substantially separate conduit circuits, one including the head cooling jacket and the radiator, and the other including the block cooling jacket but not the radiator; but, if it is greater, the control system establishes a combined conduit circuit including both the head and block cooling jacket and also the radiator. If the block jacket cooling fluid temperature is greater than a block fan trigger temperature equal to or slightly higher than the warmup completion temperature, then: if the head jacket cooling fluid temperature is less than a head fan trigger temperature less than the warmup completion temperature, the control system makes the fan system blow relatively weakly; while, if the head jacket cooling fluid temperature is greater than this head fan trigger temperature, the control system makes the fan system blow relatively strongly.

Claims

1. A cooling system, for an internal combustion engine cooled by flow of cooling fluid and comprising a cylinder head and a cylinder block, comprising:

(a) a cylinder head cooling jacket through which cooling fluid circulates to cool said cylinder head;

(b) a cylinder block cooling jacket through which cooling fluid circulates to cool said cylinder block;

(c) a radiator;

(d) a cooling fan system for blowing air at said radiator;

(e) a fan system control system which controls said cooling fan system so that it blows air at said radiator either at a relatively high flow amount or at a relatively low flow amount;

(f) a cooling fluid conduit system for circulating cooling fluid through said head cooling jacket, said block cooling jacket, and said radiator in various selectable flow patterns;

(g) a control valve system for thus selectably controlling said circulating flow of controlling fluid in said cooling fluid conduit system;

and

(h) a control system for;

(h1) if the temperature of the cooling fluid in said block cooling jacket is less than a certain predetermined engine warmup completion temperature value, so controlling said control valve system as to circulate cooling fluid through a combined circuit of said cooling fluid conduit system including both said head cooling jacket and said block cooling jacket but not substantially including said radiator, and meanwhile so controlling said cooling fan system, via said fan system control system, as to cause said cooling fan system to blow air at said radiator at said relatively low flow amount;

(h2) if the temperature of the cooling fluid in said block cooling jacket is greater than said predetermined engine warmup completion temperature value, then;

(h21) if the temperature of the cooling fluid in said block cooling jacket is less than a certain predetermined engine overheating temperature value which is higher than said predetermined engine warmup completion temperature value, so controlling said control valve system as to circulate cooling fluid through two substantially separate circuits of said cooling fluid conduit system, one including said head cooling jacket and said radiator, and the other including said block cooling jacket without substantially including said radiator;

(h22) if the temperature of the cooling fluid in said block cooling jacket is greater than said predetermined engine overheating temerature value, so controlling said control valve system as to circulate cooling fluid through a combined circuit of said cooling fluid conduit system including said head cooling jacket and said block cooling jacket and also substantially including said radiator;

and

(h3) if the temperature of the cooling fluid in said block cooling jacket is greater than a predetermined block fan system trigger temperature value which is equal to or slightly higher than said predetermined engine warmup completion temperature value, then;

(h31) if the temperature of the cooling fluid in said head cooling jacket is less than a certain predetermined head fan system trigger temperature value which is less than said predetermined engine warmup completion temperature value, so controlling said cooling fan system, via said fan system control system, as to cause it to blow air at said radiator at said relatively low flow amount;

and

(h32) if the temperature of the cooling fluid in said head cooling jacket is greater than said predetermined head fan system trigger temperature value, so controlling said cooling fan system, via said fan system control system, as to cause it to blow air at said radiator at said relatively high flow amount.

2. A cooling system according to claim 1, wherein said relatively low flow amount is a substantially zero flow amount.

3. A cooling system according to claim 2, wherein:

said control valve system comprises a compound valve comprising;

a casing formed with first through fifth valve chambers, said fist valve chamber being communicated with said second second valve chamber via a first valve port, said second valve chamber being communicated with said fifth valve chamber via a second valve port, said first valve chamber being communicated with said third valve chamber via a third valve port, said third second valve chamber being communicated with said fourth valve chamber via a fourth valve port, and said fourth valve chamber being communicated with said fifth valve chamber via a fifth valve port; and

first through fifth valve elements each controlling communication through the corresponding one of said first through fifth valve ports;

said cooling fluid conduit system comprises a first conduit communicating said first valve chamber to an inlet of said radiator, a second conduit communicating said second valve chamber to an outlet of said block cooling jacket, a third conduit communicating said third value chamber to an outlet of said head cooling jacket, a fourth conduit communicating said fourth valve chamber to an inlet of said block cooling jacket, a fifth conduit communicating said fifth valve chamber to an outlet of said radiator, and a sixth conduit communicating said fifth valve chamber to an inlet of said head cooling jacket;

and

said control system comprises;

a first thermosensitive actuator responsive to the temperature in said second valve chamber and for, when said temperature in said second valve chamber is less than said predetermined engine overheatng temperature value, moving said first valve element to close said first valve port and moving said second valve element to open said second valve port;

while, when said temperature in said second valve chamber is greater than said predetermined engine overheating temperature value, moving said first valve element to open said first valve port and moving said second valve element to close said second valve port;

a second thermosensitive actuator responsive to the temperature in said fourth valve chamber and for, when said temperature in said fourth valve chamber is less than said predetermined engine warmup temperature value, moving said third valve element to close said third valve port, moving said fourth valve element to open said fourth valve port, and moving said fifth valve element to close said fifth valve port;

while, when said temperature in said fourth valve chamber is greater than said predetermined engine warmup temperature value, moving said third valve element to open said third valve port, moving said fourth valve element to close said fourth valve port, and moving said fifth valve element to open said fifth valve port;

a head cooling fluid temperature sensor for sensing the temperature of the cooling fluid circulating through said head cooling jacket and for outputting a signal representative thereof, and a block cooling fluid temperature sensor for sensing the temperature of the cooling fluid circulating through said block cooling jacket and for outputting a signal representative thereof;

and a control mechanism, for actuating said cooling fan system when the output signal from said head cooling fluid temperature sensor is indicative of a head cooling fluid temperature higher than said predetermined head fan system trigger temperature value and also the output signal from said block cooling fluid temperature sensor is indicative of a block cooling fluid temperture higher than said predetemined block fan system trigger temperature value, and for otherwise deactuating said cooling fan system.

4. A cooling system according to claim 1, wherein said predetermined block fan system trigger temperature value is substantially equal to said predetermined engine warmup completion temperature value.

5. A cooling system according to claim 1, wherein said fan system control system can control said cooling fan system so that it blows air at

said radiator either at a relatively low flow amount, at a first relatively high flow amount, or at a second relatively high flow amount which is higher than said first relatively high flow amount, and wherein said control system further is for, if the temperature of the cooling fluid in said block cooling jacket is greater than said predetermined block fan system trigger temperature value:

if the temperature of the cooling fluid in said head cooling jacket is less than said predetermined head fan system trigger temperature value, controlling said cooling fan system, via said fan system control system, so as to cause it to blow air at said radiator at said relatively low flow amount;

but if the temperature of the cooling fluid in said head cooling jacket is greater than said predetermined head fan system trigger temperature value, controlling said cooling fan system, via said fan system control system, so as to cause it to blow air at said radiator at said first relatively high flow amount if the temperature of the cooling fluid in said block cooling jacket is less than said predetermined engine overheating temperature value, and at said second relatively high flow amount if the temperature of the cooling fluid in said block cooling jacket is greater than said predetermined engine oveheating temperature value.

6. A cooling system according to claim 1 or claim 5, wherein said cooling fan system consists of just one cooling fan, and no other cooling fan is provided for blowing air at the radiator.

7. A cooling system according to claim 6, wherein said cooling fan is electrically powered.

8. A cooling system according to claim 7, wherein said relatively low flow amount is a substantially zero flow amount, and wherein said fan system control system comprises an ON/OFF switching device which controls supply of electrical energy to power said fan.

9. A cooling system according to claim 7, wherein said relatively low flow amount is a substantially zero flow amount, and wherein said fan system control system comprises a variable power supply device which controls supply of electrical energy to power said fan.

10. A cooling system according to claim 6, wherein said cooling fan is rotatively powered from a crankshaft of said internal combustion engine.

11. A cooling system according to claim 10, wherein said fan system control system comprises a clutching device which controls supply of rotary power from said crankshaft to power said fan.

12. A cooling system according to claim 5, wherein said cooling fan system consists of a plurality of cooling fans.

13. A cooling system according to claim 12, wherein said cooling fans are electrically powered.

14. A cooling system according to claim 1, wherein said control system comprises a head cooling fluid temperature sensor for sensing the temperature of the cooling fluid circulating through said head cooling jacket and for outputting a signal representative thereof, and a block cooling fluid temperature sensor for sensing the temperature of the cooling fluid circulating through said block cooling jacket and for outputting a signal representative thereof.

15. A cooling system according to claim 14, wherein said control system controls said fan system control system and said control valve system, based upon said output signals from said head cooling fluid temperature sensor and said block cooling fluid temperature sensor.

16. A method of operating a cooling system, for an internal combustion engine cooled by flow of cooling fluid and comprising a cylinder head and a cylinder block, comprising (a) a cylinder head cooling jacket through which cooling fluid circulates to cool said cylinder head;

(b) a cylinder block cooling jacket through which cooling fluid circulates to cool said cylinder block;

(c) a radiator;

(d) a cooling fan system for blowing air at said radiator;

(e) a fan system control system which controls said cooling fan system so that it blows air at said radiator either at a relatively high flow amount or at a relatively low flow amount;

(f) a cooling fluid conduit system for circulating cooling fluid through said head cooling jacket, said block cooling jacket, and said radiator in various selectable flow patterns; and

(g) a control valve system for thus selectably controlling said circulating flow of cooling fluid in said cooling fluid conduit system;

said method comprising the processes, simultaneously performed, of;

(h) if the temperature of the cooling fluid in said block cooling jacket is less than a certain predetermined engine warmup completion temperature value, so controlling said control valve system as to circulate cooling fluid through a combined circuit of said cooling fluid conduit system including both said head cooling jacket and said block cooling jacket but not substantially including said radiator;

but if the temperature of the cooling fluid in said block cooling jacket is greater than said predetermined engine warmup completion temperature value;

(h1) if the temperature of the cooling fluid in said block cooling jacket is less than a certain predetermined engine overheating temperature value which is higher than said predetermined engine warmup completion temperature value, so controlling said control valve system as to circulate cooling fluid through two substantially separate circuits of said cooling fluid conduit system, one including said head cooling jacket and said radiator, and the other including said block cooling jacket without substantially including said radiator;

or (h2) if the temperature of the cooling fluid in said block cooling jacket is greater than said predetermined engine overheating temperature value, so controlling said control valve system as to circulate cooling fluid through a combined circuit of said cooling fluid conduit system including said head cooling jacket and said block cooling jacket and also substantially including said radiator;

and

(i) if the temperature of the cooling fluid in said block cooling jacket is less than a predetemined block fan system trigger temperature value which is equal to or slightly higher than said predetermined engine warmup completion temperature value, then so controlling said cooling fan system, via said fan system control system, as to cause said cooling fan system to blow air at said radiator at said relatively low flow amount;

but if the temperature of the cooling fluid in said block cooling jacket is greater than said predetermined block fan system trigger temperature value, then;

(i1) if the temperature of the cooling fluid in said head cooling jacket is less than a certain predetermined head fan system trigger temperature value which is lower than said predetermined engine warmup completion temperature value, so controlling said cooling fan system, via said fan system control system, as to cause it to blow air at said radiator at said relatively low flow amount;

or (i2) if the temperature of the cooling fluid in said head cooling jacket is greater than said predetermined head fan system trigger temperature value, so controlling said cooling fan system, via said fan system control system, as to cause it to blow air at said radiator at said relatively high flow amount.

17. A method of operating a cooling system according to claim 16, wherein said relatively low flow amount is a substantially zero flow amount.

18. A method of operating a cooling system according to claim 16, wherein said predetermined block fan system trigger temperature value is substantially equal to said predetermined engine warmup completion temperature value.

19. A method, according to claim 16, of operating a cooling system wherein said fan system control system can control said cooling fan system so that it blows air at said radiator either at a relatively low flow amount, at a first relatively high flow amount, or at a second relatively high flow amount which is higher than said first relatively high flow amount, wherein, if the temperature of the cooling fluid in said block cooling jacket is greater than said predetermined block fan system trigger temperature value:

if the temperature of the cooling fluid in said head cooling jacket is less than said predetermined head fan system trigger temperature value, said cooling fan system is so controlled, via said fan system control system, as to cause it to blow air at said radiator at said relatively low flow amount;

but if the temperature of the cooling fluid in said head cooling jacket is greater than said head predetermined fan system trigger temperature value, said cooling fan system is so controlled, via said fan system control system, as to cause it to blow air at said radiator at said first relatively high flow amount if the temperature of the cooling fluid in said block cooling jacket is less than said predetermined engine overheating temperature value, and at said second relatively high flow amount if the temperature of the cooling fluid in said block cooling jacket is greater than said predetermined engine overheating temperature value.

20. A method of operating a cooling system, according to claim 16, said control system comprising a head cooling fluid temperature sensor for sensing the temperature of the cooling fluid circulating through said head cooling jacket and for outputting a signal representative thereof and a block cooling fluid temperature sensor for sensing the temperature of the cooling fluid circulating through said block cooling jacket and for outputting a signal representative thereof, wherein said fan system control system and said control valve system are controlled based upon said output signals from said head cooling fluid temperature sensor and said block cooling fluid temperature sensor.