US2332680A - Cooling system for liquid jacketed engines - Google Patents

Description

" 26, 1943. J. H. WALLACE 2,332,530

COOLING SYSTEM FOR LIQUID JACKETED ENGINES Filed June 8, 1942 Patented Oct. 26, 1 943 UNITED STATES PATENT OFFlCE COOLING SYSTEM FOR LIQUID JACKETED ENGINES John H. Wallace, Los Angeles, Calif.

Application June 8, 1942, Serial No. 446,198

'7 Claims. (Cl. 123-174) This invention relates to a method and apparatus forcooling liquid jacketed engines.

Heretofore, liquid jacketed engines have been cooled by a cooling liquid for which two passages have been provided externally of the liquid Jack- 5 et, one of which includes a radiator. A thermostat has been" employed to control the flow through these passages so that when the engine is'relatively cold either all or a substantial part of the cooling fluid is circulated through that external passage which does not include the radiator. Then; as the engine warms up the thermostat serves to open the other passage and cause all or a substantial portion of the flow to take place through the passage that includes the radiator.

In the cooling of internal combustion engines many advantages are derived from having the temperature of thecooling liquid at or above the normal boiling pointof the liquid. The use of thermostats in high temperature cooling systems is objectionable for numerous reasons, including the'inability of the thermostat to be sufliciently sensitive at temperatures in the neighborhood of theboilingpoint-of the liquid, the lag in the operation-'of'the thermostat, and danger of then-1;

thermostat either order; I

A primary-object of the present invention is r to provide acooling system for liquid jacketed engines having two' circulatory external passages one of which includes a radiator, and to provide a more sensitive and prompt control of the flow of the cooling liquid through these passages than is affordedby a thermostat; In accordance with the present invention the control mechanism that regulates the flow of cooling liquid through the two circulatory passages is responsive to pressures" developed in the system whereby an increase of pressure developed in the system due 40 to the boiling of the liquid brings about animmediate and highly sensitive regulation? In this way, a much'more sensitive and prompt regulation is secured than that afiorded by thermostat controls As a partof the combination, the invention contemplates closing the cooling system during normal'operation so as to maintain the system under' pressures'that may be developed due to the boiling of the liquid and utilizing the devel- 50 oped pressures to regulate the flow through the circulatory passages.

Another object of the invention i to provide a cooling system for liquid jacketed engines having the-above-described characteristics, wherein 5 breaking or getting out of means is provided for allowing air in the cooling system to escape or to be expelled from the system, and after the air has been expelled, to then close the system to retain the pressure developed'to operate the control mechanism and to'also prevent unnecessary loss of cooling fluid or cooling fluid vapors.

The air that is allowed to escape is that air that is normally present in the top of the radiator or heat exchanger when the engine is cold or prior to its having been started. The term air as herein used not only includes this initial air that may be in the system but also non condensable vapors that may be introduced into the system. These non-condensable vapors are for example carbon monoxide and carbon dioxide that leakinto the'water jackets from the cylinder such as passed the cylinder head gasket.

The ability of the present system to expel the air and non-condensable vapors and to thereafter seal itself is highly advantageous, particularly in respect to eliminating air pocketsin the radiator or condenser as well as in the pump that may be in the system and from the water jackets themselves.

With the foregoingand other objects in view, "which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the ac-' companying drawing for an illustrative embodiment of-sthe invention, wherein:

Figure 1 is a view in side elevation of a liquid jacketed internal combustion engine, parts being broken away and shown in vertical section illustrating the system embodying the present invention as having been applied thereto; and

Fig. 2 is a sectional view through a float valve which preferably forms a part of the present system.

Referring to the accompanying drawing wherein similar reference characters designate similar parts throughout, 10 indicates an internal combustion engine having a water jacket H. The outlet from the liquid or water jacket is generally indicated at II which leads to two circulatory passages externally of the engine. One such passage is provided by a pipe I3 of relatively large capacity which leads back to a point near the bottom of the water jacket where there is disposed the conventional circulating pump I that is usually a centrifugal pump driven by the en gine I0. The other passage comprises a pipe! 5 leading from the water jacket outlet l2 to the top tank is of a heat exchanger or radiator,

generally indicated at H. The heat exchanger In this out-let there may also be termed a condenser. The bottom tank of the radiator or condenser is indicated at l8 and a pipe or conduit l9 leads from the bottom tank back to the inlet to the pump. Thus, the lower ends of the two passages meet together at theinlet to the pump. If desired, a suitable mixing chamber may be located at the junction, The entrance s to .the

seats 20 and 2| on sure within thiscirculatory passage. The inside of the bellows is subjected merely to atmospheric pressure through an aperture-26 and within the bellows there is a spring 21 the compression of which maybe adjusted by anut'or the equivalent 28. When the engine is cold the spring 21 is effective to shift the valve stem 24 so that,

valve 22 is closed and valve 23 'is fully. opened. As pressure is developed within the system this becomes effective on the exterior of th bellows which shifts the stem 24 to open valve 22 and to lose valve 23 a correspcnding amount.

29 indicates a filling nipple through which cooling liquid can be supplied tothe system. The nipple is equipped with a pressure cap 30 which preferably carries a safety valv -3| designed to open whenever pressures in the system become excessive but to retain therein normal pressures.

A float valve chamber 33 is mounted on the top of the radiator and has its top closed as at 34 around a downwardly extending tube 35. This tube provides at'its bottom a-seat 36 for a needle valve 31 operable by a float 38. '39 indicates an air ntrapping space around the tube 35. The bottom of the float valve chamber communicates past the open needle valve.

' tially all of the air ditions a substantial portion, 7 a cooling liquid is then circulating through the with the top of the radiator through a small 7 aperture 40. The float valve is preferably located slightly above the level of the top of the radiator with its inlet 40 disposed at the extreme top of the radiator tank, thus permitting any air or non-condensable gas to pass into theval've chamber and permitting the escape of the air orv non-condensable gas. This arrangement, while desirable, is not essential and the float Valve may be considerably below or above the top tank of. the radiator. However, if it is below the tank the escape of any air or. non-condensable'gases which may enter the system after the engine is in operation cannot be expelled or all'owedto f l The operation and advantages of the-system, as above-described,are as follows: Assuming that the engine is cold and is started in its operation there will normally be asmall air space in the upper tank IB'above the level of liquid therein. The valves 22 and 23 are in the position shown. During the initial operation of the engine cooling, liquid in the -water jacket is circulated through the passage ailord'edb the conduit l3 entirely, valve 2-2 being closed. This liquid isreturned to the pump M. forced back into the water jacket, out through the outlet 12, and, past the open valve 23 Continued operation quickly brings this small amount of circulated liquid up to the boiling temperatureof theliqui'd.

As steam is generated in' thewater jacket this increases the volume of-nuid inthe system with .the result that the level of liquid in the upper tank It rises, expelling the air in the upper tank v Finally, someof the liquid is forced through inlet 40 after substanhas been expelled. This liquid that is forced over into the float valve chamber is effective upon-the float "to elevate it and cause the needle valve to seat, thus closing thes'ystem' against any further egress.

Continued operation of the engine then be-' comes effective to build upa pressure inthe system which is effectiveupon the bellow/s25. As

the pressure increases the bellows 25 becomes effective tos'hift the stem 24 audio open valve 22 and close valve 23 a corresponding amount. Thus the second or auxiliary circulatory passage is automatically brought into operation and the primary pasage I3 is either partially or completely closed off. Under normal running conif not all, of the radiator llbefore being returned through the pump l4 tothe water jacket. With this arrangement it will 'be'appreciated that there -is no-ther-.

mal lag after the float operated needle valveihas been closed. Small changes'in-temperatu're jm-J mediately manifest themselves as changes .ini pressure in the closed system which areinstant-- 1y transmitted to the bellows andiresult-in im-..- 'mediateregulation. Asthe air is xpelled? from. the system and the system isthen closed,.'loss1of circulation fluidby escaping vapors is effectively prevented. High temperature or vapor ephase cooling is "readily accomplished .without danger of the resultant loss of vapors of5the cooling.

liquid and a breakdown ofthesystem.-i"As -;ithe system is operating under pressureyliqui'dis supr' plied to the pump at positive pressure sort'hat danger of flashing within thepurripv isieliminatecl.v The pump is 'primed at all'times."

When the engine is shutidow'n there isficom si'derable residual heat in the-cylinders oi'r'the engine. This residual heat, whichrmus'tibercan ried off, is effective to'maintain oridevelop-eveh higher pressures in the system with 'the.,resul.t that the valve -22-is held"open-iand cooling;cone

i tinueseven after the engine andIpumpH-jhave been shut down on the prmciplebtafthermoe siphon. the water circulating fronithefra'diator through the pump, the water Jacket, andathe auxiliary circulatory passage formed"'by-;the con duit t5 which leads to the radiatont Finally, when the engine'has been cooled below the-boiling point of the liquid by this thermosiphoning'action the'co'oling liquid contracts insthe system developing a partial vacuum therein-t Thisvacuum is efiective-to-suck or drawback-liquid in the needle valve chamber 33 .through'th inlet hole '40 with the result that the'float chamber-is emptied of liquid and the needle valve is'opened'preparat'o'ry to a subsequent starting. oftthe engine.

The inlet 40 is relatively smallgbeihgih the neighborhood of A; or possibly q s-with the. result that liquid onc in the valve cha'mber tends to remain there. Non-condensable "gases that maybe introduced into the system, such'as those that leak into the water jacket past the cylinder 1 head' gasket, may rise, 'collectin-the7-uppr tank of the top of theradiator-an'dpass 'therefrom into the valve chamber. The'valve onc closed would normally tend to remain-closed by th'e liquid forced therein and retained the'r'e in' by' the small inlet 40. However; "whemthe alon -condensable vapors or gases collect th'e'seftend to collect in the valve chamberabove the level of liquid therein and as they u ifdupft" y' 'force some of the liquid in the valvecha'mber t'o be 'exasaaeso pelled back into the radiator through the inlet 40. When such liquid is expelled the level of liquid in the valv chamber drops allowing the needle valve to open and these non-condensable gases which may be fed into the system slowly but continuously are given an opportunity to escape.

From the above-described construction it will be appreciated that the improved system is highly advantageous in that it uses but a single pump which is primed at all times and which has liquid supplied thereto under positive pressure. The system adequately takes care of residual heat of the engine after the engine has been shut down and eliminates air from the radiator. By the use of a pressure responsive control over the two circulatory passages a prompt regulation is secured which is a decided improvement over thermostat controls wherein there is invariably a lag in the regulation. Although-the air is first allowed to beexpelled from the system the generation of vapors subsequently does not bring about an escape of these vapors or a consequent loss of cooling liquid.

Various changes may be made in the details of construction without departing from the spirit or scope of the invention as defined by the appended claims. 7

I claim: v

1. In combination with a liquid jacketed en'- gine, means providing a circulatory passage for cooling fluid externally ofthe jacket, and means for allowing air in'said passagefto be expelled from said passage-and thereafter closing said passage to maintain pressures developed therein.

2. In combination with a liquid jacketed, engine, means providingv two circulatory passages for COOliIigiflllld externally of thejacket, one of said passages including: a. radiator, means for mutually varying. the rate of flow through said passages, and means for allowingair in the radi ator passage to be expelled therefrom and thereafter clos'ethe radiator passage to'retainthe pressures developed therein. V

3.1a combination with a liquid-jacketed engine, means providing two circulatory passages for cooling fluid externally of the jacket, one of said passages including a radiator, means responsive to pressures developed in the radiator passage for opening the radiator passage and correspondingly closing the other passage, and means for opening theradiator passage for the release of air therefrom and thereafter closing the radiator passage to retain pressures developed therein.

4. In combination with a liquid jacketed engine, means providing two passages for circulating cooling fluid externally of the Jacket, one of said passages including a radiator, a pump to which both passages lead for returning cooled fluid to the jacket, and means for allowing air to be expelled from the radiator and thereafter closing the radiator passage against the escape of pressure therefrom.

5. In combination with a liquid jacketed engine, means providing two passages for circulating cooling fluid externally of the jacket, one of said passages including a radiator, a pump to which both passages lead for returning cooled fluid to the jacket, means responsive to pressure developed in the jacket for opening the passage that includes the radiator and correspondingly closing the other passage, and means for allowing air to be expelled from the radiator and thereafter closing the radiator passage against the escape of pressure therefrom.

' 6. In combination with a radiator of w-liquid jacketed engine cooling system, means providing an air outlet therefrom, and a float actuated valve in said air outlet arranged to permit air to be expelled therefrom and thereafter closed to retain pressures developed therein.

7. In combination with a radiator of a liquid jacketed engine cooling system, means providing an air outlet therefrom, a float actuated valve in said air outlet arranged to permit air to be expelled therefrom and thereafter to retain pressures developed therein, and means deilning an air chamber in the air outlet above said valve within which air may be entrapped.

JOHN H. WALLACE.

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