US2231939A

US2231939A - Cooling system for internal combustion engines with liquid cooling

Info

Publication number: US2231939A
Application number: US227613A
Authority: US
Inventors: Nallinger Fritz
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1937-09-06
Filing date: 1938-08-31
Publication date: 1941-02-18
Anticipated expiration: 1958-02-18

Description

Feb. 18, 1941. F- Nl-FINGER `2,231,939 cooLINa SYSTEM Fon INTmNAL coMBusIIoN ENGINES WITH LIQUID cooLING Filed Aug. 51, 195s Uni/@Irfan- F`RI7"Z NALLJNGER `tormeg/Is Patented-Feb. 18, 1941 UNITED STATES ,PATENT .OFFICE COOLING SYSTEM FOB INTERNAL vCOM- BUSTION ENGINES WITH LIQUID COOL- ING Fritz Nallinger, Stuttgart, Germany, assigner to Daimler Benz Aktiengesellschaft, Stuttgart-A Unterturkheim,Germany Application August 31, 193s, serial No. 227,613 In Germany September 6, 1937 9 claims. (ci. 12s-114) avoid the difilculties due to bad heat transition and to the low speciilc heat of such liquids.

Instead of glycol e. g. also glycerine or mineral oils .are used. y

It has been endeavoured to obtain better results 1o with glycol cooling, by more advantageous feeding ot the cooling medium in the cylinder, by special ribs and the like, without such cooling having given full satisfaction. The endeavours to avoid the existing disadvantages by simple means have i5 resulted in that for obtaining a more intensive cooling effect while retaining the ordinary cooling systems, simply the quantity in circulation of cooling liquid, that is of the glycol, has been increased. Such an increase is, however, limited in 20 the radiators because in the case of large circulating quantities these radiators must be given too large passage cross-sectional areas and consequently-their degree of ejillciency drops.

These disadvantages are overcome according to 25 the invention in that a large sized suction and pressure pump maintains the cooling 'liquid in uninterrupted circulation through the cooling spaces of the engine and a secondary circulation is deilected from the suction conduit of the pump 30 by which only a portion of the circulating liquid is returned through the radiator to the main circulation, so that in the case of small dimensioned radiator, the largest possible quan-tity of liquid can be conducted through the engine. The par- 35 ticular advantages are therefore obtained owing to the fact that for the cooling liquid flow, two circulations are provided, one of which effects the circulation of the cooling liquid in the engine itself, whereas the other circulation, deected 40 from the first one, conducts a part flow of cooling liquid through the radiator of ordinary dimensions. A separate pump or pumping system may be provided for each circulation or also this part ow can be branched oi! to the radiator through 45 correspondingly dimensioned nozzles or pipe conduits. When two pumps viz. pumping systems are employed, the leed pump eilecting the cooling water circulation in the engine must be larger than the pump viz. pumping system provided for 50 the part ilow through the radiator. A large quantity of cooling liquid is conducted through the cooling spaces at a high speed oi ilow by the large cooling liquid pump eilecting the internal circulation in they engine, so that the heat exchange ss between the engine and the cooling liquid is very intensive. For re-coollng the vliquid charged with heat a smaller part ilow is then separated from the main circulation and conducted through the radiator which can consequently be of normal dimensions and have a high degree of efficiency. 5

It is clear that there must be a' certain ratio beg tween the amount of liquid circulating through the engine and the dimensions of the radiator toensure a good working of the system, this ratio depending on the average amount of heat produced by the engine and the speciiic heat and heat conductivity A`of the liquid used.

Instead of using two pumps viz. pumping systems of dierent sizes, a single large pump or` pumping system may also be provided which effects the circulation in the main cooling ilow andirom which a part ilow is branched oil to the radiator through suitably dimensioned nozzles or pipe conduits. Instead by means of such a nozzle the amount of liquid circulating in the part ilow may also be determined by the output of the pump.4 Means to adjust the output of the pump are then provided. For suitably regulating the part' ilowthrough the radiator an adjustable throttle element is preferably tted in the suction conduit.

It is immaterial for the invention whether glycol or some. other suitable cooling medium, possibly also water with an addition, is used. The essential point is only that a large flow or liquid is conducted through the cooling spaces of the engine and that only a part ilow passesthrough the normally dimensioned radiator, so that --its degree of eillciency remains within reasonable limits. It is furthermore essential that a large and eillcient pump-or two such pumps-are used, viz. pumping systems.

Several embodiments of the invention are illustrated by way. 'of example in the accompanying drawing, in which: 40

Fig. 1 shows a cooling system for internal combustlon engines with two cooling pumps,

Fig. 2 isa similar arrangement with only one cooling pump from whose suction conduit a part ilow is branched of! to the radiator.

An internal combustion .engine a is equipped with a radiator b and with pumps c and d for the cooling liquid which pumps are driven from the main shaft of the engine for example through the intermediary of bevel wheels q. For the internalv cooling liquid circulation of the engine the large sized 4pump c is provided which forces the cooling liquid through a pipe h to the cooling spaces oi the engine and thence sucks it back through a pipe i. From the pipe i a pipe m sa cooling temperature is branches, through which a portion of the cooling liquid is deiiected and returned by the pump d to the main pressure pipe h through the radiator b' suction pipe i may be prowith a throttle or shutofl sectional area. Furthermore an adjustable throttle element g may be tted in the suction; pipe i after the point where pipe e branches oil'. The quantity of liquid owing through the radiator can be accurately regulated by` this throttle element g. After pressing through the radiator b the part iiow is returned `throughapipe o to the main ilow, in the pipe i andthence fed by the pump c to the cooling spaces ofthe engine a.

By the cooling system according to the inveni non the not cccling liquid ci the main circulation c, h, a, i is repeatedly mixed with the portion of the liquid re-cooled in the radiator b andthus a obtained which changes within permissible limits.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. A cooling system for internal combustion engines with liquid cooling by means of liquids with bad heat transfer lcomprising a liquid pump of large capacity, means to drive this pump, a pipe leading from the cooling spaces of the engine to this pump, a pipe leading from the upperv part of the engine to the suction side of the pump,

a radiator, a pipe leading from the upper part of the radiator to the pipe connecting the upper part oi' the engine with the suction side ofthe pump. a nomle in this part of the pipe system, nally a pipe connecting the lower part of the radiator with the suction side of the pump.

2. A cooling system for internal combustion engines with liquid cooling by means of liquids with bad heat transfer comprising a pump of large size, means to drive this pump, a pipe leading from the cooling spaces of the engine to this pump, a pipe leading from the upper part of the connecting the lower part of the engine to the suction side of the pump, a radiator, a pipe leading from the upper part of the radiator to the pipe connecting the upper part of the engine with thc suction side of the pump, a n'o ein this part of the pipe system, nally e, pipe. necting the lower part of the suction side of the pump, a throttle element being provided in the pipe leading to the upper part of the engine between the points where the pipes from the radiator discharge into this pipe.

3. A cooling system for internal` combustion engines with liquid cooling by means of liquids with bad heat transfer comprising a pump oiv large size, means to drive this pump, a pipe leading from the cooling spaces. of the engine to this pump, a pipe leading from the upper part of the engine to the suction side oi the pump, a radiator, a pipe leading from the upper part of the radiator to the pipe connecting the upper' part of the engine with the suction side ot the pump, means to adjust the output of the pump, finally a pipe radiator with tbf.l suction side of the pump.

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radiatorwith the- '4. A cooling system for internal combustion engines with liquid cooling by means of liquids having low heat transmission, comprising the combination, with a main circulation and a cooler connectedthereto, of a liquid pump of large 5 `capacity delivering the cooling liquid into the main circulation through the cooling spaces of the engine and a second liquid pump of relatively smaller capacity with an auxiliary circulation delivering only a limited part of the circulating liquid through the cooler to the main circulation, the limited part of the auxiliary circulation being smaller than the remaining part or the main circulation'.

5. Cooling system for internal combustion engines with liquid cooling by means of liquid cool'- ing media with bad heat transfer, comprising two liquid pumps oi' different output capacities, means -for driving the two pumps, a cooling liquid pipe of large dimensions for the entire cooling liquid comprising a pipe leading lfrom the output por-l tion of a cooling chamber of the engine involved to the suction side of the larger pump and a return pipe from the delivery side of said larger pump to the receiving portion of the 'engine cooling chamber, a smaller pipe for a part of the entire circulating cooling liquid branching oil from the pipe between the upper part of the engine and thesuction side of the larger pump comprising a radiator, a pipe leading from the branching point on the large pipe of the cooling liquid to the upper part of the radiator, a pipe leading from the lower side of the radiator to the suction side of the smaller pump and a pipe leading from the delivery side of the smaller pump to the delivery side of the larger pump, and a throttling member in the suction pipe of the larger pump between the branching point of the smaller pump and the suction pipe connection of the larger pump.

6. A cooling system for internal combustion engines with liquid cooling by means of liquids having low heat transmission, comprising the combination, with a main circulation and a cooler connected thereto, of a liquid pump of large capacity delivering the cooling liquid into the main circulation through the cooling spaces of the engine and a second liquid pump of relatively smaller capacity with an auxiliary circulation delivering only a limited part of the circulating 50 of said engine likewise communicating with said 60 cooling spaces, said conduit and cooling spaces forming a closed circuit with one of said pumps included in said circuit and a throttling member likewise included in said circuit, a second closed circuit including a conduit connected at the two ends thereof to the ilrst mentionedJ circuit so as to form a shunt circuit therefor and having the second pump and said radiator included in said second circuit, said throttling member in the first circuit positively controlling the flow of liquid not 70- only through the ilrst pump, but also the liquid ilowing through the second pump and the radiator by limiting the ilow in said ilrst circuit.

8. A cooling system according to claim '1, in.' which the output capacities of the two pumps are different so that the rst pump has a larger output capacity than the second pump.

9. Ina cooling system for internal combustion engines with liquid cooling by means of 'cooling liquid media having poor heat transfer and having pump means and a. radiator, there being means for driving the pump means. the combination of a, conduit connected at o ne end with one portion of the engine. in communication with the cooling chambers therein and at the other end with another'portion of said engine likewisec'o'mmunic'at'ing with said cooling chambers, saidconduit and cooling chambers forming a closed circuit with at least part of the pump means included in said circuit and a throttling member also included in said circuit, a second closed circuit including a conduit connected at the two ends thereof to the rst mentioned circuit so as to form a, shuntcircuit therefor and having said radiator included in said second circuit, said throttling member in the rst circuit 'positively controlling the ow of liquid not only through the irst circuit, hutalso the ow of liquid through vthe second circuit and the radiator bylimiting theiiio'w i said ilst circuit.

. AFRITZ NAILINGER.