US1317709A - Combtjstion engines - Google Patents

Description

G. KEITH AND W. A. WHATMOUGH.

MEANS FOR CONTROLLING THE SUPPLY OF COMBUSHBLE MIXTURE T0 INTERNAL COMBUSTION ENGINES.

a APPLICATlON FILED MAR. 29, 1919. 1,817,709. Patented Oct. 7,1919.

2 SHEETS-SHEET I.

G. KEITH AND W. A. WHATMOUGH.

MEANS FOR CONTROLLING THE SUPPLY OF COMBUSTIBLE MIXTURE T0 INT NAL COMBUSTION ENGINES.

APPLICATION FILED MAR. 29,1919. 1,817,?09. Patented Oct. 7,1919.

2 SHEETS-SHEET 2.

GEORGE MEANS FOR CONTROLLING THE SUPPLY OF COMBUSTIBLE MIXTURE '10 KEITH AND WILFRED AMBROSE WHATMOUGH, OF LONDON, ENGLAND.

INTERNAL- COMBUSTION ENGINES.

Application filed March as, 1919. Serial No.

To all whom it may concern Be it known that we, GEORGE KEITH and VVILFRED AMBROSE WHA'rMoUGn, both subjects of the King .of the United Kingdom of Great Britain and Ireland, and residing at London, England, have invented a certain new and useful Improvement in Means for Controlling the Supply of Combustible Mixture to Internal-Combustion Engines, of which the following is aspecification.

This invention relates to means for con trolling the supply of a mixture of fuel andair to internal combustion engines, for example, to engines of automobile vehlcles.

One object of the invention is to insure approximately constant quality of the mixture irrespective of the engine speed or load,

or of barometric pressure. Anotherobject is to render practicable the employment of.

combustible gas or vapor from any source; ,6. g}, of vapor produced by evaporation of any suitable fuel.

Yet another object is to render it possible to obtain efficient carburation in engines which are beyond the scope of the ordinary jet or spray carbureters.

Like the construction described in the specification ofthe co-pending application No. 232421, the present invention involves the provision of a governor operated by pressure functions of the components of the mixture and adapted to maintain a difference of. pressure across the gas or vapor supply regulator proportionate to the, difference between the pressure at the point of entry of fuel into the induction pipe and the pressure at some other selected point in the induction system.

For convenience it may the purpose of the following explanation of the governing arrangements,

be assumed, for

that the combustible medium to be admixed with air is available in a gaseous, state. is brought to a given-pressure (lower than the pressure at which it is supplied) by means of the governor device and thence'led past the vapor supply regulator or obturator, adjustable in accordance with the desired proportions constituting the mixture, and induced to flow into the induction pipe or manifold through which is also inspired the air for combustion.

Specification of Letters Patent.

This medlum The governor device is provided with a suitable inlet valve con- 1 trolled by a'piston one side of which is exposed to the pressure of the combustible medium, and the other side of which is ex posed to the pressure existing at some. selected point in the induction system where there is a higher pressure than exists at the point of admission of fuel to the induction pipe. The difference of pressure between these two points will vary with the rate of flow through the induction pipe as the square of the velocity of such flow. The action of the governor is to set up the same difference of pressure across the obturator. As the rat of flow of combustible medium past the obturator varies as the square root of the pressure difference between the two sides of the obturator it follows that the proportion ofcombustible medium to air will remain constant whatever engine.

Tocontrol the engine speed, there is provided a throttle valve which may be located Patented 0ct.7,1919.

the demand of the I in front of or behind the point where the I slightly so as to compensate for the inward leakage of air at the valve stems, etc, and

also to insure ignition under the lower pres'- sure. This desideratum may be realized by the application of a light spring or other load to the piston, urging the piston in the direction to maintain the'valve open.

While a diaphragm governor can be successfully used as tion of application No. 232421 it is found that a piston is the most practical arrangement owing to the limitations imposed by the higher temperatures.

With a suitable piston the influence of weight may be overcome by operating in the horizontal direction, or the piston can be worked in a verticaldirection if suit-ably counterbalanced.

A valve, preferably of a balanced type, is fitted to the piston and so arranged as to described in the specificaopen when the piston moves 'inward,and to v the induction pipe. For this reason the invention is particularly suitable for aeroplane or airship engines, in that the mixture is unaffected by variations of barometric pressure due to varying altitudes, as also in that,

when desired, the engines can be super:

charged when in higher altitudes without upsetting the quality of the mixture. I Due to the maintenance of constant proportions of the mixture, a higher efficiency in fuel consumption is obtained than is possible with the usual type of jet or spray carbureter. The efficiency is further increased owing to the fact that fuel is sup-' plied in the vaporous state, so that, no matter under What condition the engine is running, a more intimate mixture is .effected than is possible where a liquid fuel is merely sprayed or atomized. v

It is common knowledge that, at low speeds and loads liquid fuel in the ordinary carbu-reter is not so Well atomized as at higher speeds and loads, owing tothe-lower velocity of air past the fuel jet or jets,and

difliculty due to defective atomization increases with the sizes of carburetor and jet so that there is a practical limit to the size of engine that can be efiiciently run on the jet -carbureterprinciple, even where a num-' ber of carbureters or jets are used.

The difliculty in question does not arise where the present invention is adopted.

Where the fuel used is in the liquid state,

for the purpose of this invention it isnecessary to convert it into a vaporous state and maintain it in such vaporous state until j exploded. D

For the purpose in View it is essential that it has been mixed with air and the mixture the combustible medium should have an approximately constantvalue, so that it is not admissible tovaporize it by spraying it with air into a hot chamber, as is common practice in the use of fuels with a high boiling point such as paraffin; v

I As it is intended to utilize the heat of the engine exhaust to vaporize the fuel by boiling-it in the absence of air, the form of the vaporizer is very important where there is not a large margin between the exhaust temperature and the boiling point of the last fractions of the fuel used.

The improved vaporizer is preferably constituted by a superposed series of interconnected chambers or cells each compris- Lsimoe leading to the ing two shallow conical frusta disposed with their bases adjacent and located in a horizontal plane, each chamber being divided into two compartments by a .partition,

formed with marginal perforations. A pipe for the admission of liquid fuel is connected to the uppermost compartment of the vaporizer, the liquid being fed in'preferably cascade fashion downward, being spread into thin layers'on thehot walls and partitions. The resultant vapor is led off prefunder pressure and constrained to flow erably by a central pipe from the lower chamber to the admission valve of the gov ernor.'. The pressure of vapor is. approxi mately equal to the initial pressure of the liquid fuel, so that when the vapor pressure tends to exceed this limit the flow of liquid is retarded or stopped; conversely, if the-vapor pressure be reduced, the fuel flows in more rapidly. The Va orizer therefore Works on the flash 'princlple and is not intended to fuel.

The vaporizer is housed in an enlargement of the exhaust pipe which is fitted with anvhold any body of unvaporized nular baffles whereby the exhaust products are kept in a state of turbulence and constrained to follow a tortuous course in intimatecontact with the conical walls of the vaporizer, which latter, in turn, present a H large area exposed to the action of heat.

Such an arrangement not only constitutes a very eflicient device for vaporizing fuels of high or low boiling point, but also functions as an effective silencer.

In order to prevent violentos cillations of pressure inthe vaporizer, it is advantageous to control the admission of liquid fuel by a throttle valve mechanically connected to the main throttle so that the amount of 'fuel admitted will roughly a proximate to the demand of the engine. non-return valve fixed on'the fuel pipe also assists to steady the pressure of the vapor in the vaporizer.

Provision is made to prevent establish- I ment of any dangerous vapor pressure due to the eventual boiling'of an accidental collection of liquid fuel in the lowest part of .the vaporizer by leading a pipe from the sa d lowest partback to the tank from whichthe liquid is fed under pressure, such pipe being fitted with a non-return valve and preferably connected to the tank above the level of the liquid .fuel. The non-return valve permits fuel to flow from the vapor- -izer to the tank should the pressure in the vaporizer at any time exceed that in the tank I I Anadditional safety device may be used to prevent the flow of liquids into the vaporlzer when the latter cools owing to stoppage of the engine. The safety device employed consists of a .stop valve on the fuel pipe vaporizer in series with the throttle valve above referred to, which stop valve is normally kept closed by means of an adjustable spring. The valve spindle is connected to a diaphragm working in a diaphragm chamber; from the diaphragm chamber a pipe connection is taken to the induction pipe of the engine, the'arrange .ment being such that when the engine is running there is sufiicient suction on the diaphragm to pull the valve 011' its seat against the action of the spring, thus permitting fuel to flow to the vaporizer.

When the engine stops, as there is no suction in the induction pipe, the valve is closed on its seat by a spring. r

, As shown in Fig. 7 of the drawings, in lieu of the employment of a governor with valve for controlling the flow of vapor from the vaporizer, the piston or other moving niember of the governor may be operatively connected to a cock through" which passes liquid fuel that maybe led thence for example by 'way of a braided wire or the like to the uppermost compartment ,of the vaporizer, the interior of which latter is fully open to the inner face of the piston, and vapor geninduction pipe system.

erated in which is conveyed directly from the vaporizer by way ofv an obturator to the In the accompanying drawings which illustrate the invention, Figure 1 shows a complete vaporizer with a piston governor device. Fig. 2 is a sectional detail view, to a larger scale, of the piston governor device.

.Figs.. 8, t'and 5 are detail views showing one form of valve device for proportioning the supply of liquid fuel approximately to p the demand. Fig. 6 shows a device for controlling the delivery of fuel to the vaporizer. Fig. 7 shows an arrangement in which the governor'isarranged to control the admis-.

sion of liquid fuel to the vaporizer.

- 'Referring to Fig. 1, the vaporizer shown is constituted by a series of su erposed interconnected chambers or cells K, A A A comprising pairs of 'shallow conical frusta. disposed with their bases adjacent and located in horizontal planes, each of the'chamhere A, A A being divided into twocomp-artments by a partition formed with marginal perforations.

A plpe B for the admission of liquid fuel is connected to the uppermost compartment i the vaporizer under pressure from the tank A of the vaporizer, the liquid being constrained to-flow cascade fashion downward and'being spread into thiniayers on the partitiOIiSl I -The vapor is preferably drawn off from the lower part of the vaporizer by, means of the pipe W. The liquid fuel is supplied to i A B, and is controlled in'its passage by the throttle valve It and an automatic valve (3 erable by a diaphragm pin in the chamber p as hereinafter described.

A pipe connection 13 is taken fromthe lower part of the vaporizer back to the fuel tank B and is fitted with a non-return valve B the function of the pipe B being to return to the tanks-any fuel in the vaporizer in the event of the pressure in the vaporizer rising to any appreciable extent above that in the tank B. l

The vaporizer is housed in a preferably cylindrical chamber G, into which leads the exhaust pipe D, and which is fitted with annular bafiies E, whereby the exhaust prodnets are constrained to follow a tortuous course in intimate contact with the conical walls of the vaporizer on their way to the exhaust discharge pipe, F.

The governor shown to enlargedscale in Fig. 2 includes a piston G, movable 'horizontally in a cylindrical chamber G inclosedin a jacket having free communication withthe exhaust gases, said chamber G having communication with the vaporizer by way of a piston valve' which in the arrangement shown consists of a tube U easily slidable axially'of the chamber in the movement of the piston G. At one end the tube U is formed with a flange U embraced between the piston G and a notch plate G secured to the piston G and straddling the order to insure equality of pressure. A connection Gr is taken from the outer side of the piston G to the induction pipe. Z de notes a drain-pipe for carrying off any convdensed fuel which may pass to the outside of the piston G. M denotes a light spring servmg to load the piston slightly at lower speeds, the spring urging the piston in thedirection to open theports X of the valve U. The fuel vapor, after passin through the obturator Valve Q, passes d ownward by means of a pipe at led t-hrough the exhaust discharge pipe F to the throat 'of the Venturi ,tube 6. A jacket pipe 0 surrounds the pipe a after it leaves the pipe F and a acket d ,also surrounds the Venturi tube 6.

' A portion of the exhaust gases passes along the jacket 0 into the jacket 03, and may be discharged through holes e in the latter.

The usual throttle valve'f is fitted between the Venturi tube 6 forming part of the induction pipe to the engine. At the lower end of the Venturi tube'bra float feed carburetor g, or other suitable device, may be fitted for starting purposes, provision bej operate ing made for cutting ofi the supply of fuel from the carbureter when once the engine is running on the vaporizer.

Figs. 3, 4 and 5 illustrate in detail views one form of the valve device shown to small scale in Fig. 1 for proportioning the liquid screw-down valve k may be adjusted;

There are desirably alsofitt'ed in the supply passage a stop valve is and a non-return valve Z. The fuel enters under pressure at the connection m and isdelivered to: the va-' porizer from the connection n. The functlon of the non-return valve Z is tovreduce I the liability to surging of fuel in the pipe leading to the vaporizer.

Fig. 6 shows a diaphragm-operated device of which the diaphragm chamber is indicated at p in Fig. 1, said device being adapted to permit admission of liquid fuel to the vaporizer only while the engine is running. The said device may be fitted to the fuel pipe B in series with the valve device h just described, and consists of a valve and spindle 0 connected to a diaphragm p, or the like, working in a chamber 10', an 'ad' justable spring 9 being arranged to keep the valve normally closed. From thediaphragm chamber 1) a pipe connection '1' is taken to a point in the mduction pipe between thethrottle valve 7 and the engine, as shown'in Fig. 3. The arrangement issuch that when the engine is running there is sufficient suction on the diaphragm p to pull the valveo off its seat against theaction of thespring 9, thus permitting flow-of liquid fuel to Y the vaporizer. When the engine stops, as there is no suction in the induction pipe, the valve 0 is closed on to its seat by the spring In the construction. shown in Fig. 7, the piston governor is arranged to control the admission of liquidfuel to the vaporizer so as to effect generation of vapor according to the ,pressure set by the governor in lieu of first generating vapor at a higher pres sure and then lowering the pressure by the action of the governor..

In the construction shown in Fig: 7 the fuel enters at the connection 8 and passes through the cockt, the lever t of which "is operated by means of the piston in such a" way as to admit fuel'when the piston moves 7 inward and cut off the fuel when the piston moves outward. -From the cock t the fuel wire w or the like.

from the throttle valve mechamsm whereby the radial position of the ceramic vFig. 7 also shows an arrangement for revaporating any condensate which may form in the governor chamber, which arrangement may-be also used in connection with the system'shown in' Fig. 3. 7

Between the uppermost chamber A of the vaporizer proper and the governor chamber is an additional chamber A, which may be constructed similarly to the chambers A, A A and which is in communication with 715 the governor chamber G butisolated from the vaporizer chambers.

What we claim is I 1. In combination, a vaporizer, means for supplying liquid hydrocarbon fuel thereto, an induction pipe through which a mixture of fuel andai'r is sucked to an internal combustion engine, a tubular connection between i said vaporizer and said induction pipe, a throttle valve in said induction pipe, a man- 35 ually adjustable valve or obturator for. regulating the delivery of gaseous fuel from said vaporizer to said tubular connection, a chamber, a piston movable in said chamber,

a valve automatically operated by said piston and controlling the passage of gaseous fuel from said vaporizer to said tubular connection, and a communicating connection be: tween said induction pipe and said iston chamber whereby the movements 0 piston will be controlled by pressure or suction in said induction pipe.

' 2. In combination, a vaporizer,-means for supplying liquidhydrocarbon fuel thereto,

an induction pipe through which a mixture 9- of fueland air is sucked to an internal combustion engine, a tubular connection between said vaporizer and said induction pipe, a throttle valve in said induction pipe, a man: ually adjustable valve or obturator forreg- 1 ulating the delivery of gaseous fuel from. said vaporizer to said tubular connection,

a chamber, a piston movable in-said chamber, a valve automatically operated by said piston and controlling the passage of gaseous fuel from said vaporizer to said tubular connection, a communicating connection between said induction pipe and said piston chamber whereby f the movements of said piston will be controlled by pressure or suction in said induction pipe, a spring-pressed fuel inlet controlling valve, a chamber, a diaphragm arranged in said chamber and serving to operate said fuel inlet controlling valve, and a tubular connection between said diaphragm chamber and said inductionpipe at a point in the latter between said throttle valve and the engine.

3. In combination, a vaporizer,- means for supplying'liquid hydrocarbon thereto, an in-. duction pipe throu h which a mixture of fuel andQair is suc ed to an internal :combustion engine, a tubular connection between said vaporizer and said induction pipe, a

throttle valve in said induction pipe, a man- 1,30

said 95 ually adjustable valve or obturator for regulating the delivery of gaseous fuel from said vaporizer to said tubular connection, a chamber, a piston movable in said chamber, a tubular valve movable with said piston and'controlling the passage of gaseous fuel from said vaporizer to said tubular connec-v tion, and a communicating connection bea liquid fuel vaporizer, a tubular'connection tion pipe and said piston between said vaporizer and said induction pipe, a valve serving to control communication between said vaporizer and said tubular connection, an obturating member for regulating the delivery of vapor from said tubular connection to said induction pipe, a chamber in communication with said vaporizer, and a piston movable in said chamber, said piston being operatively connected to said valve, and a communicating connection between said induction pipe and said iston chamber whereby said piston will be controlled by pressure or suction of the componentsof the mixture in said induction P In combination, an induction pipe through which a mixture of fuel and air is sucked to an internalcombustion. engine, a I

passage for exhaust gases, a vaporizer in said passage, a tubular connection between said vaporizer and said pipe, said tubular connection extending through said passage, a valve serving to control communication between said vaporizer and said tubular connection, an obturating member for regulating delivery of vapor from said tubular connection to said pipe, a chamber in communication with said vaporizer, a piston movable in said chamber, said piston being operatively connected to communicating connection between inducchamber whereby said piston Will be controlled by pressure or suction of the components of the mixture in said induction pipe. v

6. In combination, an engine exhaust pipe, a chamber connected to said. pipe, a vaporizer in said chamber, said vaporizer comprising connected cells each consisting of two conical frusta having adjacent bases and an interposed partition having marginal tubular connection,

perforations, an vapor, a tubular connectlon between sa d induction pipe for air and vaporizer and said induction pipe, a-valve regulating the How of'vaporthrough said and means whereby said valve may be opened or closed more or less according to the pressure or suction in said induction pipe. 1

said valve, and a 7. In combination, an exhaust pipe for products of combustion, a chamber connected to said exhaust pipe and fitted with annular bafl'les, a vaporizer in said chamber, said vaporizer comprising connected cells alternating with said bafiles, an induction pipe for air and vapor, a tubular connection between said vaporizer and said induction pipe, said tubular connection extending through said exhaust pipe, a valve regulating the flow of vapor through said tubular connection, and means whereby said valve may be openend or closed more or less according to the pressure or suction in said induction pipe,

8. In combination, an exhaust pipe for products of combustion, a chamber connected to said exhaust pipe, a vaporizer in said."

chamber, said vaporlzer comprising a series of superposed vaporizing cells, a cylinder chamber, a. piston movable in said cylinder chamber, a; valve operatively connected to said piston, and a vaporizing cell insaid first-named chamber isolated from said superposed cells, said last-named cell serving for re-ivaporization of condensate which may accumulate in said cylinder chamber, an induction pipe, and a tubular connection between said cylinder chamber and said in- 1 duction pipe.

9. In combination, an induction p1pe,-a throttle fitted to said pipe, at vaporizer, a

tubular connection between said vaporizer 1 and said induction pipe, a governor controlling the passage of vapor through said connection, a tubular connection for'admission of liquid fuel to said vaporizer, and a valve member fitted in said second named connection and operatively connected with said throttle. I

' 10. In combination, an induction pipe through which a mixture of fuel and air is sucked to an internalcombustion engine, a throttle fitted to said pipe, a vaporizer, a tubular connection between said vaporizer and said induction pipe, means for controlling the delivery of vapor through said tubular connection, a tank for supply of fuel to said vaporizer, a tubular connection between said tank and said vaporizer, a nonreturn valve interposed in said last-named tubular connection, and a return tubular connection from the lower end of said vaporizer to said tank,

11. In combination, an induction pipe through which a mixture of fuel .and air is sucked'to an internal combustion engine, a

Nthrottle fitted to said pipe, a source of fuel supply, a tubular connection between said source of fuel supply and said pipe, a manu- ,.ally adjustable obturator for regulating the delivery of fuel from said tubular connection to said pipe, a chamber, a piston, movable in said chainber, a tubular piston valve slidtion'between said induction pipe and said piston chamber whereby the movements of "said piston and the valve operated thereby will be controlled by the pressure or. suction In said mductlon pipe.

' 12. In combinatlon, an induction pipe through which a carbureted mixture of fuel andv air is sucked to an internal combustion engine, a vaporizer, means for supplying a liquid fuel to said vaporizer, a valve for automatically controlling the supply of liquid fuel to said vaporizer, a valve for automatically controlling the passage of vapor from said vaporizer, chambers containing 15 means for operating saidvalves, and tubular connections between said induction pipe and said chambers whereby said valves will be controlled by the suction or pressure in said induction pipe. 20 In testimony whereof we have si ned our names to this specification in the presence of two subscribing Witnesses.

GEQRGE KEITIL I WILFRED AMBROSE WHATMOUGH. .Witnesses:

HENRY MAsoN, ISABEL ROLLO.

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