US3159153A

US3159153A - Heater system for liquid cooled internal combustion engines

Info

Publication number: US3159153A
Application number: US253382A
Authority: US
Inventors: Ralph E Thomas
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-01-23
Filing date: 1963-01-23
Publication date: 1964-12-01
Anticipated expiration: 1981-12-01

Description

R. E. "rHoMAs HEATER SYSTEM FOR LIQUID COOLED INTERNAL COMBQSTION ENGINES Filed Jan.' 25, 1965 INVENTOR.

United States Patent O 3,159,153 WATER SYSTEM FOR LIQUID COULED EJ- TERNAL CDMBUSIION ENGINES Ralph E. Thomas, 44 Hickory, Troy, Mich. Filed Jan. 23, 1963, Ser. No. 253,332 12 Claims. (Cl. 12S-142.5)

This invention relates to a liquid coolant circulation system for internal combustion engines which functions to maintain the engine in a heated condition even during long periods of engine idleness under cold weather conditions. More specically, the subject matter of my invention is a coolant circulation system for internal combustion engines, which includes a coolant heater operative during periods of engine idleness to maintain the coolant in the engine block at `a predetermined temperature sucient to expedite cold weather starting.

Various systems have heretofore been proposed for maintaining an internal combustion engine at a relatively high temperature during engine idleness in coldweather to expedite starting. One of the Inost common of such systems incorporates an electrically heated or a gas or other fuel lire coolant heater with inlet and outlet connected into the normal coolant circulation system of the engine such that during engine idleness hot coolant can continue to be fed through the engine block to thereby maintain it at a relatively high temperature. In any such system there are two main problems. First, there is that of assuring efficient circulation of the coolant from the heater to the engine block and then back to the heater. The second problem is that of assuring that the coolant heater ceases operation once the engine is warmed up. Prior proposed systems are deficient in one or both of these respects.

One of the principal objects of my invention is the provision of a system of the type described, wherein eilicient circulation `of the coolant from the heater to the engine block and then back to the heater is accomplished solely by convection. Another object is to provide a coolant heater system which, by reason of the circulation of the coolant between the engine block and the heater, assures that the heater remains inoperative while the engine is in a heated condition. Briefly, these objects are accomplished in accordance with the invention by connecting the coolant heater into the normal engine coolant system in such a way that there is relatively unrestricted convection induced flow of hot coolant from the heater to engine during periods of engine inoperativeness, but with the flow of hot coolant being in the direction of the heater lonce the engine is operative and in a fully heated condition. A heat-sensing device in thesystem causes the heating element in the heater to operate only when the temperature of the coolant is below a certain predetermined level. Hence, the heater is operative `to maintain the coolant and therefore the engine warm while the engine is idle and would normally become cold, but becomes inoperative while the engine is operating at its normal temperature. These and other features and advantages of the invention will appear more clearly from the following detailed description of a preferred embodiment thereof, made with reference to the appended drawings in which: FIGURE 1 is a side elevational fragmentary view, partially schematic, of a preferred embodiment of they invention; and

FIGURE 2 is a view taken on a line 2-2 of FIG- URE l.

"Referring now to FIGURE l, there is shown a liquid- `cooled, reciprocating type internal combustion engine comprising an engine block 4 having the normal coolant passages therein, a radiator 6 having top and bottom headers 8 and 1li respectively, and coolant conduits or hoses 12 and 14 of conventional about 11/2 diameter,

3,159,153 Patented Dec. 1, 1964 ICC conduit 12 leading from the bottom header to the engine block and conduit 14 forming a passage from the top of the engine block up to the top header 8. A coolant pump 16 operates while the engine is running to pull coolant from the engine block and circulate it upwardly through conduit 14 to the header 8, down through the radiator and thence back to the engine block through the conduit 12. A thermostat 18 at the top of the engine block and in the conduit 14 is operative to fully open the passage in the conduit when the coolant has reached a predetermined temperature, say F., the thermostat having a permanently open small passage 20 therethrough which provides communication between the header 8 and the engine block even when the coolant is below 180 F. 4and the thermostat is in its closed position. The top header of the radiator is provided with a filler opening having a pressure radiator cap 22, of conventional construction, to maintain a pressure in the coolant system of about 3 to 4 pounds per square inch, or even higher, above normal atmospheric pressure while the engine is running. It will be noted that as thus far described the coolant circulation system shown is conventional though, as will be seen from the following further description, some of the components thereof perform functions in accordance with the present invention which are in addition to and different from their normal functions.

In accordance with the invention, the system shown includes a coolant heater 24 which comprises an outer generally box-shaped metal shell 26, a gas pilot light and burner assembly 28 with a coolant temperature sensitive control 30 and a coolant heating chamber 32 positioned above the gas burner assembly. The chamber 32 has a conduit 34 of about 3A" diameter communicating with the engine block and another conduit 36 of the same diameter extending upwardly and communicating with lthe top header 8 of the radiator. Metal housing 26 is provided with suitable air inlets 38 to provide ample oxygen for the burner 28 and with an outlet 40 at the top to allow exit of the exhaust gases from the burner. A fuel tank 42 for the burner is suitably mounted on the fire wall of the vehicle and has a fuel feed line 44 leading to the burner control mechanism 30. In this particular embodiment, butane gas is used to fuel the burner; however it will be understood that other gases or liquid fuels, or even an electric resistance heating element, can be used for the heater if desired. The burner-pilot light assembly can be of conventional well-known construction, the precise details of this assembly forming no part of the present invention. Control 30 has a main gas feed line 45 which leads to the main burner and a small feed line 48 leading to the pilot light. A fail-safe control device 50, also of conventional construction, leads back'to the control mechanism 30 to assure that the gas flow to the pilot light is cut off in the event the pilot light goes out. Control 30 includes a heat-sensing element 52 having its heat-sensing portion in the coolant chamber 32 adjacent the opening for conduit 34, such heat-sensing element being operative through the control mechanism to regulate the ow of gas 'to and hence the ignition of the main burner so as to maintain the coolant above a predetermined temperature. A regulator, indicated at 54, is provided on `the control 30 so that the predetermined temperature can be set. Such heat-sensitive burner controls are well known, and the precise details of construction thereof form no part of the present invention. In the particular control shown, the heat-sensing element comprises a heat-expansible metal rod which has an end threadedly supported adjacent the end of conduit 34 in the interior of the heating chamber 32, and a pointed oppositely disposed end which projects into the control mechanism 30, the pointed or tapered end serving as a valve for the flow of gas into the tube 46 which communicates with the burner. Moves, 1 es, 1 53 ment of the regulator 54 to the desired predetermined minimum temperature for the coolant rotates the rod such that its threaded connection determines the length thereof and hence the amount of heat required to induce elongation to the extent that the pointed end closes the gas flow line 46. As indicated above, the details of this mechanism form no part of the presen-t invention, and any other suitable heat-sensing control device for actuating the burner may be used if desired.

It will be noted that the coolant heating chamber 32 is loca-ted below the horizontal level of the radiator header 8 such that the conduit 36 must extend generally upwardly from the heating chamber to the header. Further, and as can best be seen in FIGURE 2, it will be noted that the opening 56 for the conduit 36 into the top header is positioned just above the horizontal center line of the opening 58 for the conduit 14 which leads to the header from the engine block. For reasons which will be evident from the following description of the operation of the system, ythese are important features of the invention.

Operation of the system is as follows: Assume first that the truck, bus, or other vehicle in which the system is being used is parked outdoors on a cold winter night, f

.and hence is exposed to a temperature well below freezing. Assume further that the control 30 for the heater has been given a setting of 50 F. After the vehicle has been parked for a short time with the engine shut off, the coolant temperature will drop down to 50 F., at which time the control 30 will operate to light the burner `and hence heat the coolant in the chamber 32. As the coolant in the lchamber 32 becomes heated, normal convection lwill cause the heated coolant to rise through the `conduit 36 and into the header 8 through the yopening 56. Referring to FIGURE 2, it will be noted that the liquid level in the header at this time, with the engine inoperative and the coolant temperature relatively low, is about on the horizontal line of the opening 58, this being .the normal idle engine coolant level for the reason hereinafter specied. Hence, the opening 56 is above the -liquid level and opens into that portion of the header which is occupied by simply air or water vapor For ythis reason, the hot coolant moved by convection up the pipe 36, can empty freely into the header 8 without the blocking effect or resistance which `would occur if the opening 56 were below the liquid level. The hot coolant emptying from the opening 56 into the header is then free to oW through opening 58 down through the conduit 14, through the opening 20 in the thermostat and into the engine block. Such circulation causes coolant to flow out of the engine block through conduit 34 and into the heating chamber 32. Hence, circulation of coolant from the heater to `the header 8 through the engine block and then back to the heater continues until the temperature of the coolant rises above 50 F., at which ltime the control 30 causes the 'burner to cease operation until the coolant temperature drops below 50, at which time the above cycle repeats. In this way the temperature of the coolant, `and therefore the temperature of the engine block, .is maintained at about 50 F., irrespective of the length of time the vehicle stands idle.

When the engine is started, which starting is quite easy ybecause the engine hasbeen maintained in a heated rcondition, the thermostat 18 will be in its closed position, and 'hence the pump 16 Will cause circulation of the coolant from the radiator, through the bottom header thereof, to the engine block and thence through the conduit 34, heating chamber 32 and conduit 36 back to 'the radiator, lsome slight amount of circulation possibly also being caused through the small opening 20 in the thermostat. Rather shortly after the engine has commenced operation, the liquid level in the header rises above the `bottom of opening 56, this rise in liquid level always occurring because of the expansion of the coolant as it becomes heated, and

also because of the ebullition in the system caused by sure builds up in the upper header due `to the pressure cap closure 22. Assuming a F. thermostat is being used, when the coolant reaches this temperature the pump 16 causes normal coolant circulation between the radiator and the engine, i.e., circulation from the bottom of the radiator through the engine block and thence through the conduit 14 to the top header and again through the radiator. When the system reaches such condition, since the liquid level in the header is above opening 56 and since there is pressure in the header, hot coolant from the header is caused to also flow downwardly through conduit 36 in the direction of the heater and into the heating chamber 32. By means 'of this reverse flow of coolant into the heater when the engine is in a normally heated condition, the coolant in the heating chamber 32 remains well above 50 F., and hence the burner will remain inoperative during the entire period of continued engine operation and until the vehicle is again allowed to stand idle for suiiicient period to cause the coolant temperature to drop below 50 F. The reverse ow feature has the special advantage of assuring that the coolant in the heating chamber 32 will be at close to the sarne temperature as that in the engine block when the vehicle is parked and the engine shut off.

As indicated above, the liquid level in the system will be such that when .the engine is cool it willbe at about the horizontal center line of the opening 58, and when hot will rise to the level of the opening 56. This is normal since the radiator header is provided with a conventional overflow pipe 60 (see FIGURE 2) located aboverthe opening 58, and also slightly above the opening 56. Hence, the liquid level even with the engine running is never substantially above opening 56 and normal cooling causes the liquid level to dr-op slightly below opening 56 when the engine is idle.

As indicated above, the heating chamber 32 must be located below the horizontal level of the header 8. Actually, it has been found highly desirable for optimum eiiciency, that the chamber 32 be positioned as vlow as practical and preferably below the connection of conduit 34 with the engine block.

It will be readily apparent that the present invention is easily adaptable to engines of diifering configurations than that shown in the drawing. For example, should the radiator of the engine be disposed below the upper level of the engine block, the outlet conduit from the heater tank would communicate with the top of the block rather than with the radiator header. This would be so since it is important to have such .conduit communicate with the cooling system of the engine slightly above the highest vlevel therein.

It will be evident from the above description that the present Vinvention provides a coolant heater .and circulation system which affords optimum eiciency in maintaining the engine warm during periods of idleness, while at the same -time assuring against unnecessary heater operation while the engine is hot.

While the invention has been described specically with reference to a preferred embodiment it will be understood that various changes and modications can be made all within the full and intended scope of the claims which follow.

I claim:

1. A liquid coolant heater for an internal combustion engine having a liquid coolant circulation system comprising a coolant heating chamber having two conduits communicating with the engine coolant circulation system to allow circulation of the coolant through the heating chamber, heating means for the coolant in said charnber, and kcontrol means for actuating said heating means when the coolant temperature ydrops `below a predetermined temperature, one of said conduits from the heating chamber communicating with the -engine coolant system below the upper level of the coolant in said system for ilow of coolant therethrough and the other said conduits communicating with the engine coolant system at a level which is above that of the coolant in said system when the engine is inoperative and the coolant is below said predetermined temperature for flow of coolant therethrough.

2. A liquid coolant heater for an internal combustion engine having a liquid coolant circulation system cornprising a coolant heating chamber having two conduits communicating with the engine coolant circulation system to allow passage of coolant through the heating chamber, said heating chamber being located below the upper level of the liquid coolant in the circulation system, heating means for the coolant in said chamber, and control means for actuating said heating means when the coolant temperature drops below a predetermined temperature, one of said conduits extending upwardly from the heating chamber and vcommunicating with the engine coolant system below the upper level of the coolant in said system and permitting coolant flow therethrough and the other said conduits communicating with the engine coolant system at a level which is above that of the coolant in said system when the engine is inoperative and the coolant is below said predetermined temperature to permit coolant flow therethrough.

3. A liquid coolant heater for an internal combustion engine having a liquid coolant circulation system which includes a radiator with a topl header, said heater comprising a coolant heating chamber located below said header and having two conduits communicating with the engine coolant circulation system to allow passage of the coolant through the heating chamber, heating means for the coolant in said chamber, and control means for actuating said heating means when the coolant temperature drops below a predetermined temperature, one of said conduits from the heating chamber communicating with the engine coolant system below the upper level in the coolant in said system aud permitting coolant flow therethrough and the other of said conduits communicating with said header at a level which is above that of the coolant in said header when the engine is inoperative and the coolant is below said predetermined temperature to permit coolant ow therethrough.

4. A liquid coolant heater for an internal combustion engine having a liquid coolant circulation system comprising a coolant heating chamber located below the upper level of the coolant in said system and having two conduits communicating with the coolant circulation system to allow passage of the coolant through the heating chamber, heating means for the coolant in said chamber, and control means for actuating said heating means when the temperature of the coolant in said heating chamber drops below a predetermined temperature, one of said conduits from the heating chamber communicating with the engine coolant system below the upper level in the coolant in said system and permitting coolant ow therethrough and the other said conduits communicating with the engine coolant system at a level which is above that of the coolant in said system when the engine is inoperative and the coolant is below said predetermined temperature to permit coolant flow therethrough.

5. A liquid coolant heater and circulation system for a liquid-cooled internal combustion engine comp-rising an engine block having liquid coolant passages therethrough, a radiator communicating with said engine block to allow circulation of coolant therebetween, a coolant heater with a coolant heating chamber therein and conduits providing communication between said heating chamber and said radiator and engine block, said conduits being arranged to cause circulation of liquid coolant through the heating chamber in one direction when the coolant in the heating chamber is at a higher temperature than that in the engine block and to cause circulation of the coolant into the heating chamber in the reverse direction when the coolant in the engine block is at a higher temperature than that in the heating chamber.

6. A liquid coolant heater and circulation system for a liquid-cooled internal combustion engine comprising an engine block having liquid coolant passages therethrough, a radiator with a top header located above the top level of the engine block and communicating with said engine block to allow circulation of coolant therebetween, a coolant heater with a coolant heating chamber therein located below the level of said header and having conduits providing communication between the heating chamber, the header, and the engine block, said conduits causing circulation of liquid' coolant through the heating chamber in one direction when the coolant in the heating chamber is at a higher temperature than that in the engine block and causing circulation of the coolant into the heating chamber in the reverse direction when the coolant in the engine block is at a higher temperature than that in the heating chamber.

7. A liquid coolant heater and circulation system for a liquid-cooled internal combustion engine comprising an engine block having liquid coolant passages therethrough, a radiator with a top header having an opening located above the engine block and communicating with the engine block to allow circulation of coolant between the engine block and the radiator, said header having another opening located above said iirst-mentioned opening, a coolant heater with a coolant heating chamber therein located below said header, a conduit communicating between said heating chamber and said engine block and permitting coolant dow therethrough, and a conduit communicating between said heating chamber and the secondmentioned opening in said header and permitting coolant flow therethrough.

8. A liquid coolant heater for an internal combustion engine of the type having an engine block, a radiator with a header at the top thereof, and means for circulating liquid coolant between the block and the radiator including a conduit extending upwardly from the block to the header and communicating with the header through an opening in the side wall thereof, said heater comprising a liquid coolant heating chamber, a conduit extend-V ing upwardly from said chamber and communicating with said header through a second opening therein and permitting coolant iiow therethrough, said second opening being located above the horizontal center line of said irstmentioned opening, and a conduit communicating between said chamber and the engine block and permitting coolant flow therethrough.

9. An internal combustion engine liquid coolant circulation and heating system comprising an engine block, a radiator with a header at the top thereof, said header having a side wall with an opening therein, a conduit communicating between the bottom of said radiator and the block to allow the coolant to pass from the radiator to the block, a return conduit extending upwardly from said lblock and communicating with said header through the opening in the side wall thereof to allow the coolant to pass from the block to the radiator, coolant heater having a coolant heating chamber with one end thereof communicating with the engine block and permitting coolant tlow therebetween, a conduit extending upwardly from the other end of said coolant heating chamber to said header and communicating with said header through a second opening in the side wall thereof and permitting coolant flow therebetween, said second opening being positioned above the horizontal center line of said firstmentioned opening, and means in said heater causing it to operate to heat the coolant in said chamber when the coolant temperature drops to a predetermined level.

l0. A liquid coolant heater for an internal combustion engine of the type having an engine block, a radiator with a header at the top thereof, land means for circulating liquid coolant between the block and the radiator including a conduit extending upwardly from the block to the header and communicating with the header through an opening in the side wall thereof, said heater comprising a chamber for circulating the liquid coolant therethrough, heating means for said chamber, means for controlling said heating means in accordance with the temperature of the liquid coolant in said chamber, a cond-uit extending upwardly from said chamber and cornmunicating with said header through a second opening therein Iand permit-ting coolant flow therebetween, said second opening being located above the horizontal center line of said rst-mentioned opening, and a conduit cornmunicating between said chamber yand the engine lblock and permitting coolant iow therebetween.

1l. An internal combustion engine liquid coolant circulation and heating system comprising an engine block, a radiator with a header at the top thereof, said header having a side wall with an opening therein, a conduit communicating between 'the bottom of said radiator and the block to allow the coolant to pass from the radiator to the block, a return conduit extending upwardly from said block and communicating with said header through the opening in the side wall thereof to allow the coolant to pass from the block to the radiator, a thermostat in said second-mentioned conduit operative to fully open said conduit to the passage of coolant when said coolant reaches a predetermined temperature and having a permanently opened restricted passage therethrough, a pump on said engine block to .cause the coolant to circulate through said conduits between said block and said radiator while the engine is operating, a hydrocarbon fuel-fired coolant heater having a coolant heating chamber with one end thereof communicating with the engine block, a pipe extending upwardly from the other end of said coolant heating chamber to said header and communicating with said header through a second opening in the side Wall thereof, said second opening being positioned above the horizontal center line of said first-mentioned opening, and means in said heater causing it to opera-te to heat the coolant in said chamber when the temperature of said coolant drops to a predetermined level.

12. An internal combustion engine liquid coolant circulation and heating system comprising an engine block, a radiator with a header .at the top thereof, said header having a side wall with `an opening therein, a conduit communicating between .the bottom of said radiator -and the block to allow the coolant to pass from the radiator to the block, a return conduit extending upwardly from said block and communicating with said header through the opening in the side wall thereof to allow the coolant to pass from the vblock to the radiator, a thermostat in said second-mentioned Vconduit operative to fully open said conduit to the passage of coolant when said coolant reaches a predetermined ltemperature and having a permanently opened restricted passage therethrough, a pump on said engine block to cause the coolant to circulate through said conduits between said block and said radiator While the engine is operating, a coolant heater having a coolant heating chamber with one end thereof `communicating through an upwardly extending conduit with the4 engine block, aconduit extending upwardly from the other end of said coolant heating chamber to said header and communicating with said header through a second opening in the side -wall thereof, said secon-d opening being positioned `above the horizontal center line of said iirstmentioned opening, means for heating the coolant in said chamber, and heat-sensitive means in said chamber to actuate said heating means when the temperature of the coolant in the chamber drops to a predetermined level.

References Cited in the tile of this patent UNITED STATES PATENTS

Claims

1. A LIQUID COOLANT HEATER FOR AN INTERNAL COMBUSTION ENGINE HAVING A LIQUID COOLANT CIRCULATION SYSTEM COMPRISING A COOLANT HEATING CHAMBER HAVING TWO CONDUITS COMMUNICATING WITH THE ENGINE COOLANT CIRCULATION SYSTEM TO ALLOW CIRCULATION OF THE COOLANT THROUGH THE HEATING CHAMBER, HEATING MEANS FOR THE COOLANT IN SAID CHAMBER, AND CONTROL MEANS FOR ACTUATING SAID HEATING MEANS WHEN THE COOLANT TEMPERATURE DROPS BELOW A PREDETERMINED TEMPERATURE, ONE OF SAID CONDUITS FROM THE HEATING CHAMBER COMMUNICATING WITH THE ENGINE COOLANT SYSTEM BELOW THE UPPER LEVEL OF THE COOLANT IN SAID SYSTEM FOR FLOW OF COOLANT THERETHROUGH AND THE OTHER SAID CONDUITS COMMUNICATING WITH THE ENGINE COOLANT SYSTEM AT A LEVEL