Engine cooling system with optionally communicable head cooling circuit and block cooling circuit, and method of operating the same

Claim 1

For an internal combustion engine comprising: (a) a cylinder head formed with a head cooling jacket for cooling said cylinder head, said head cooling jacket being formed with a cylinder head inlet and a cylinder head outlet; (b) a cylinder block formed with a block cooling jacket for cooling said cylinder block, said block cooling jacket being formed with a cylinder block inlet and a cylinder block outlet; and (c) a radiator formed with an inlet and an outlet; a cooling system, comprising: (d) a first pump for impelling cooling fluid through said head cooling jacket from said cylinder head inlet towards said cylinder head outlet; (e) a second pump for impelling cooling fluid through said block cooling jacket from said cylinder block inlet towards said cylinder block outlet; (f) a block input fluid temperature sensor for sensing the temperature of the cooling fluid which passes out through said cylinder block inlet to said block cooling jacket, and for generating a sensed block input temperature signal representative of said temperature; (g) a block recirculation conduit system leading from said cylinder block outlet of said block cooling jacket so as to supply flow of cooling fluid, from a downstream part of said block recirculation conduit system, to said cylinder block inlet of said block cooling jacket; (h) a main recirculation conduit system, an upstream part of which is communicated to said cylinder head outlet of said head cooling jacket, and a downstream part of which is communicated to said inlet of said radiator; (i) a radiator output conduit system, leading from said outlet of said radiator both to said cylinder head inlet of said head cooling jacket and also to said cylinder block inlet of said block cooling jacket, said downstream part of said block recirculation conduit system being thereby communicated also to said cylinder head inlet of said head cooling jacket; (j) a first control valve for controlling flow of cooling fluid through said radiator according to a radiator flow regulation signal; (k) a flow mixing conduit which communicates a part of said main recirculation conduit system with a part of said block recirculation conduit system; (l) a second control valve for controlling flow of cooling fluid through said flow mixing conduit according to a block flow regulation signal; and (m) a controller, which receives said sensed block input temperature signal from said block input fluid temperature sensor, and which produces, based thereon, said radiator flow regulation signal which is sent to said first control valve, and also said block flow regulation signal which is sent to said second control valve; (n) whereby said controller can vary the amount of cooling operation provided for said internal combustion engine, by varying the opening amount of said first control valve, thus varying the amount of cooling fluid passing through said radiator; and can also vary the amount of mixing between the cooling circuit for said cylinder head and the cooling circuit for said cylinder block, by varying the opening amount of said second control valve, thus varying the amount of cooling fluid passing through said flow mixing conduit.

Claim 18

A method for operating a cooling system of an internal combustion engine having: (a) a cylinder head formed with a head cooling jacket for cooling said cylinder head, said head cooling jacket being formed with a cylinder head inlet and a cylinder head outlet; (b) a cylinder block formed with a block cooling jacket for cooling said cylinder block, said block cooling jacket being formed with a cylinder block inlet and a cylinder block outlet; and (c) a radiator formed with an inlet and an outlet; said cooling system, comprising: (d) a first pump for impelling cooling fluid through said head cooling jacket from said cylinder head inlet towards said cylinder head outlet; (e) a second pump for impelling cooling fluid through said block cooling jacket from said cylinder block inlet towards said cylinder block outlet; (f) a block input fluid temperature sensor for sensing the temperature of the cooling fluid which passes out through said cylinder block inlet to said block cooling jacket, and for generating a sensed block input temperature signal representative of said temperature; (g) a block recirculation conduit system leading from said cylinder block outlet of said block cooling jacket so as to supply flow of cooling fluid, from a downstream part of said block recirculation conduit system, to said cylinder block inlet of said block cooling jacket; (h) a main recirculation conduit system, an upstream part of which is communicated to said cylinder head outlet of said head cooling jacket, and a downstream part of which is communicated to said inlet of said radiator; (i) a radiator output conduit system, leading from said outlet of said radiator both to said cylinder head inlet of said head cooling jacket and also to said cylinder block inlet of said block cooling jacket, said downstream part of said block recirculation conduit system being thereby communicated also to said cylinder head inlet of said head cooling jacket; (j) a first control valve for controlling flow of cooling fluid through said radiator according to a radiator flow regulation signal; (k) a flow mixing conduit which communicates a part of said main recirculation conduit system with a part of said block recirculation conduit system; (l) a second control valve for controlling flow of cooling fluid through said flow mixing conduit according to a block flow regulation signal; and (m) a controller, which receives said sensed block input temperature signal from said block input fluid temperature sensor, and which produces, based thereon, said radiator flow regulation signal which is sent to said first control valve, and also said block flow regulation signal which is sent to said second control valve; (n) whereby said controller can vary the amount of cooling operation provided for said internal combustion engine, by varying the opening amount of said first control valve, thus varying the amount of cooling fluid passing through said radiator; and can also vary the amount of mixing between the cooling circuit for said cylinder head and the cooling circuit for said cylinder block, by varying the opening amount of said second control valve, thus varying the amount of cooling fluid passing through said flow mixing conduit; said cooling system being filled with cooling fluid; said method comprising the processes, simultaneously performed, of: (o) operating said first pump and said second pump; and (p) depending upon said sensed block output temperature signal from said block output fluid temperature sensor, performing either one or the other but not both of the following two processes (q) and (r): (q) if said sensed block output temperature signal from said block output fluid temperature sensor indicates a cooling fluid temperature at said cylinder block outlet of said block cooling jacket of less than a certain first predetermined temperature value, then simultaneously: (q1) controlling said first control valve, by said radiator flow regulation signal from said controller, so as substantially to interrupt flow of cooling fluid through said radiator; and (q2) controlling said second control valve, by said block flow regulation signal, so as to allow a flow of cooling fluid through said flow mixing conduit; (r) if said sensed block output temperature signal from said block output fluid temperature sensor indicates a cooling fluid temperature at said cylinder block outlet of said block cooling jacket of greater than said first predetermined temperature value, then simultaneously: (r1) controlling said first control valve, by said radiator flow regulation signal from said controller, so as to allow cooling fluid to flow through said radiator; and (r2) controlling said second control valve, by said block flow regulation signal, so as to allow a controlled flow of cooling fluid through said flow mixing conduit; (s) whereby, during the warming up process of said internal combustion engine, before the cooling fluid which passes out through said cylinder block outlet of said block cooling jacket has attained said first predetermined temperature, the cooling systems for said cylinder head and for said cylinder block are substantially communicated, and no substantial cooling is provided for either by said radiator, so that the heat which is supplied to the cooling fluid within the head cooling jacket is communicated to the cooling fluid within the block cooling jacket, and both the cylinder head and the cylinder block are quickly warmed up together; but, after said cooling fluid which passes out through said cylinder block outlet of said block cooling jacket has attained said first predetermined temperature, then according to process (r1) substantial cooling is provided for the cooling fluid in said head cooling jacket, while according to process (r2) the amount of cooling provided for the cooling fluid in said block cooling jacket is regulated; whereby, after said internal combustion engine has been warmed up, said cylinder block may be kept substantially warmer than said cylinder head.

Claim 19

A method for operating a cooling system of an internal combustion engine having: (a) a cylinder head formed with a head cooling jacket for cooling said cylinder head, said head cooling jacket being formed with a cylinder head inlet and a cylinder head outlet; (b) a cylinder block formed with a block cooling jacket for cooling said cylinder block, said block cooling jacket being formed with a cylinder block inlet and a cylinder block outlet; and (c) a radiator formed with an inlet and an outlet; said cooling system, comprising: (d) a first pump for impelling cooling fluid through said head cooling jacket from said cylinder head inlet towards said cylinder head outlet; (e) a second pump for impelling cooling fluid through said block cooling jacket from said cylinder block inlet towards said cylinder block outlet; (f) a block input fluid temperature sensor for sensing the temperature of the cooling fluid which passes out through said cylinder block inlet to said block cooling jacket, and for generating a sensed block input temperature signal representative of said temperature; (g) a block recirculation conduit system leading from said cylinder block outlet of said block cooling jacket so as to supply flow of cooling fluid, from a downstream part of said block recirculation conduit system, to said cylinder block inlet of said block cooling jacket; (h) a main recirculation conduit system, an upstream part of which is communicated to said cylinder head outlet of said head cooling jacket, and a downstream part of which is communicated to said inlet of said radiator; (i) a radiator output conduit system, leading from said outlet of said radiator both to said cylinder head inlet of said head cooling jacket and also to said cylinder block inlet of said block cooling jacket, said downstream part of said block recirculation conduit system being thereby communicated also to said cylinder head inlet of said head cooling jacket; (j) a first control valve for controlling flow of cooling fluid through said radiator according to a radiator flow regulation signal; (k) a flow mixing conduit which communicates a part of said main recirculation conduit system with a part of said block recirculation conduit system; (l) a second control valve for controlling flow of cooling fluid through said flow mixing conduit according to a block flow regulation signal; and (m) a controller, which receives said sensed block input temperature signal from said block input fluid temperature sensor, and which produces, based thereon, said radiator flow regulation signal which is sent to said first control valve, and also said block flow regulation signal which is sent to said second control valve; (n) whereby said controller can vary the amount of cooling operation provided for said internal combustion engine, by varying the opening amount of said first control valve, thus varying the amount of cooling fluid passing through said radiator; and can also vary the amount of mixing between the cooling circuit for said cylinder head and the cooling circuit for said cylinder block, by varying the opening amount of said second control valve, thus varying the amount of cooling fluid passing through said flow mixing conduit; said cooling system being filled with cooling fluid; said method comprising the processes, simultaneously performed, of: (o) operating said first pump and said second pump; and (p) depending upon said sensed block output temperature signal from said block output fluid temperature sensor, performing either one or the other but not both of the following two processes (q) and (r): (q) if said sensed block output temperature signal from said block output fluid temperature sensor indicates a cooling fluid temperature at said cylinder block outlet of said block cooling jacket of less than a certain first predetermined temperature value, then simultaneously: (q1) controlling said first control valve, by said radiator flow regulation signal from said controller, so as substantially to interrupt flow of cooling fluid through said radiator; and (q2) controlling said second control valve, by said block flow regulation signal, so as to allow a flow of cooling fluid through said flow mixing conduit; (r) if said sensed block output temperature signal from said block output fluid temperature sensor indicates a cooling fluid temperature at said cylinder block outlet of said block cooling jacket of greater than said first predetermined temperature value, then simultaneously: (r1) controlling said first control valve, by said radiator flow regulation signal from said controller, so as to allow cooling fluid to flow through said radiator; and (r2) controlling said second control valve, by said block flow regulation signal, so as to allow a controlled flow of cooling fluid through said flow mixing conduit; (s) whereby, during the warming up process of said internal combustion engine, before the cooling fluid which passes out through said cylinder block outlet of said block cooling jacket has attained said first predetermined temperature, the cooling systems for said cylinder head and for said cylinder block are substantially communicated, and no substantial cooling is provided for either by said radiator, so that the heat which is supplied to the cooling fluid within the head cooling jacket is communicated to the cooling fluid within the block cooling jacket, and both the cylinder head and the cylinder block are quickly warmed up together; but, after said cooling fluid which passes out through said cylinder block outlet of said block cooling jacket has attained said first predetermined temperature, then according to process (r1) substantial cooling is provided for the cooling fluid in said head cooling jacket, while according to process (r2) the amount of cooling provided for the cooling fluid in said block cooling jacket is regulated; whereby, after said internal combustion engine has been warmed up, said cylinder block may be kept substantially warmer than said cylinder head.

Claim 24

A method according to either one of claims 17 and 18, said cooling system further comprising an engine lubricating oil temperature sensor for detecting the temperature of lubricating oil contained within said cylinder block, and for producing a lubricating oil temperature signal representative thereof, said lubricating oil temperature signal being supplied to said controller.