US2055539A - Control mechanism for carburetors of internal combustion engines - Google Patents

Description

9 3 5 5 5 0, 2 L A Y B O C A Y J YD R A H R E B E Sept,l '29, 1936.

HANS- vCONTROL. MECHANISM FOR cARBUREToRs 0F INTERNAL coMBUsTIoN ENGINES 2 Sheets-Sheet -1 Filed Nov, `28, 1954 Sept. 29, 1936.

2,055,539 HANS-EBERHARD JACOBY ET AL CONTROL MECHANISM FOR CARBURETORS OF INTERNAL COMBUSTION-ENGINES Filed Nov. 28, 1954 2 sheets-shea 2 Patented Sept.` 29, 1936 UNITED STATES CONTROL MECHANISM FOR CARBURETORS OF INTERNAL COMBUSTION ENGINES Hans-Eberhard Jacoby, Wetzikon, ana Hans Nssli, Hinwil, Switzerlandy Application November 28, 1934, Serial No. 755,166

In Switzerland March 15, 1934 l 7 Claims.

This invention relates to control mechanism for carburetors oi internal combustion engines.

The accelerator of interal combustion engines has hitherto been controlled solely by touch. By.

such a method the carburetor cannot be operated with the maximum emciency and economy. The object of the invention therefore is to provide means whereby the opening and closing of the throttle is controlled more emciently and economically than hitherto.

The invention consists of a control mechanism tor carburetors of internal combustion engines in which the opening or closing of the throttle is edected by a. device controlled by the suction in the ng chamber, the degree of suction being transmitted to the device by means operated by the accelerator lever or pedal, characterized in that the throttle is connected to a piston which is mounted in a cylinder and subjected to the action of a compression spring, said piston dividing the cylinder into two chambers -Which are connected to the' atmosphere andthe mixingchamber according to the position of the control device, and that the control. device proper comprises a plug cock comprising aystationary member and a movable member co trolled by the pedal, pipe connections leading from the stationary member to the two chambers of the cylinder, to the atmosphere and to the mixing chamber and passage ways in the movable member, some or the pipe connections being opened and/or closed according to the position of the plug of the cock.

In order that the invention may be more clearly understood one particular embodiment thereof will now be described, 'by way of example, with reference to the accompanying drawings wherein:-

Fig. l is a diagrammatic sectional view of the .device showing the position of the parts when Fig. 5 illustrates an auxiliary device for use in connection with carburetors of older type.

FIg. 6 illustrates the device in the case when the carburetor. is operating with secondary air for the main jet.

In these drawings `the iloat chamber of thev carburetor with oat and needle valve is indi- (Cl. 12S-103) cated at I. From this chamber the liquid Iuei passes through the jet 2 into the current of air which flows through the venturi 'I and the mixing chamber or throttle chamber 3 past the throttle 5 into the inlet pipe 4 of the engine. 5

In the known type of carburetors the throttle 5 is operated directly by the accelerator pedal i8 Fig. 4 through the lever E, but according to the present invention the lever 6 is pivoted to a rod I3 which in turn is connected to a rod 10 i I which forms the rod of'a piston 9, and passes through a stuing box I2 fitted into the bottom of a cylinder 8. The piston 9 is subject to the action of a, compression spring I0 which normally tends to displace the piston 9 in a direc- '15 tion corresponding to'the closing of the throttle.

Furthermore, a, control device R is provided which, for example, may be in the form oi' plug cock having plug I5 provided with passage ways, hereinafter described in detail. The plug I5 has an extension I4 to which is connected an arm I6 Fig. 4 pivotally connected to a rod I'l attached to the pedal I8. Operation of the pedal I8 will therefore cause the valve body I5 of the control device R to rotate, as indicated in Fig. 4.

The casing R of the control device is connected by a pipe c to the' mixing chamber 3 in such a manner that the pipe c opens into said mixing chamber 3 between the throttle- 5 and the inlet pipe 4 of the engine. The space above the piston 9 in the cylinder 8 is connected to the casing R by a pipe line a, and the space A below the piston 9 is connected to the casing R by a pipe line b and by branch pipes e; f, and g. Furthermore, pipes b and a are interconnected by a branch 35 pipe having a restriction Z. The lower part of the casing R is provided with openings a, e and f through which the pipes a, e, f open into the atmosphere according to the respective positions of the plug I5. In the pipes Jv and g restrictions v and a: are disposed between the casing R and the pipe b.

'I'he pipe a has a branch p which leads through a restriction y to an auxiliary device T which comprises a cylinder I9 wherein is mounted a piston 2l subject to the action of a compression spring 20. The piston rod 22 of piston ZI may be actuated independently by hand, mechanically orv electrically by means of a thermostat, which measures the temperature of the engine.

The operation of the device is as follows:-

When the throttle is closed, that is when the pedal is not depressed. the parts occupy the position shown in Fig. 1. The plug cock R connects the pipe c through pipe g, restriction :r and pipe b with the space A below thepiston 9 and the pipes e and f are closed, while the pipe a communicates with the atmosphere. In this position the throttle 5 is closed automatically by the suction in the inlet pipe 4 between the throttle 5 and the engine. In the known arrangement, in which the pedal operates directly on the throttle, it frequently happens that the throttle 5 is closed suddenly when the pedal is released, for example when the vehicle is stopped. In such cases the disadvantage is experienced that a jolt is felt in the vehicle because the braking action of the engine becomestoo strongly effective. Furthermore, owing to the inertia of the moving liquid fuel the sudden cutting off of the air stream causes the fuel to overflow from the float chamber I towards the jet 2 (dripping) whereby undesirable loss ofA fuel is caused. Both of these defects are eliminated by the provision of the restriction or damper a: in the pipe y. The eilect of this restriction is to moderate the closing action of the throttle 5, so that a sudden jolt in the vehicle and loss of fuel will not occur.

When the'pedal I8 is depressed for speeding up the engine the plug I 5 is rotated with the aid of members I 1, I6 and III sothat the parts then occupy the position shown in Fig. 2. The pipes e and g are thus closed, the pipe fis connected to the atmosphere and the connection of the pipe a with the atmosphere is interrupted.

Through the pipe f atmospheric air is admitted 4to the space below the piston 9 through the restriction v and pipe b. The vacuum in the iniet pipe .E between the throttle E and the engine now becomes effective through pipe c and pipe a in the space B above the piston t. Through the restriction z air is Icy-passed from pipe b into pipe a, so that the vacuum in the pipe a. will reach a part value of the suction in pipe c according to,

the position of plug it, the movement of the throttle thereby sensitively following the uctuations of the suction. Due to thesuction in pipe a and thus in the space B piston 9 is lifted in a vcertain proportion to the counter pressure of spring III so that the piston 9 will occupy a certain position forexample that shown in Fig. 2. When the piston risesthe throttle 5 is opened by means of the connections I I, I3, t as shown in Fig. 2. The restriction c.' now that the restriction :c is inoperative, produces the same effect as described in connection with said restriction 3:, that is the damping of the movement of the throttle 5.

When the pedal I8 is brought into its end position, orI fully depressed as shown in Fig. 4 (fully opened position throttle), the plug I5 is moved into the position shown in Fig. 3. Now in addition to the pipe f, the pipe e is also connected to the atmosphere, whereby the damping action of the restriction v is destroyed, and moreover, the connection of pipe c and pipe a is no longer damped.

In the known arrangement of throttle control the position oi the throttle 5 was directly dependent upon the position of the pedal I8, but this is not the case in the arrangement described. The position of the'throttle 5 is controlled, according to the position of the plug cock, by the air speed or the suction in the inlet pipe 4 in front of the throttle 5, said suction being trans-4 mitted by the plug cock R in a sensitive manner to the space B and becoming operative there in the manner desfribed.

The described arrangement is obviously applicable to other vehicles, for example aeroplanes,

where a lever takes the place of the accelerator pedal I8.

When the engine is cold the hitherto usual speeding up of the engine may be avoided for example by causing the piston 2|, 22 of the aux-l iliary device T, which may be controlled by a known thermostat to open the pipe p (Fig. 2).

older type (e. gl without accelerator pump), the

stuing box i2 (Figs. l and 2) is constructed in the form of a cylindrical extension 23 (Fig. 5). Mounted on the piston rod I I is an auxiliary piston 26, which is adapted to displace the air column in an auxiliary cylinder 25 according to the movement of the piston 9. lFrom the uppermost point of the auxiliary cylinder 25 ve. pipe m leads to the atmosphere through the restriction s. From this pipe a branch pipe n disposed between the damper s and the cylinder 25 leads to the oat chamber I which is sealed in an air tight manner. The operation of this arrangement is as followszl `when the piston 9 is raised by the suction so as to open the throttle t the piston 2li is lifted by the piston rod Ii, so that the air in the auxiliary cylinder 2t is expelled through the pipe m. The restriction s however chokes the air being expelled, so that a pressure is developed in the pipes and u in the float chamber I, whereby the difference of pressure between the fuel level and the fuel jet 2 necessary for the feed of the fuel is temporarily increased and a greater amount of fuel is supplied, so that according to the degree of acceleration of the mixture column the temporary enrichment with fuel is effected automatically. When the piston Q descends the opposite effect is produced, air being drawn through the restriction s andfjpfpe m, so that a vacuum is established in the o'ibhamber i causing a reduction in the suppl" --f fuel.

In carburetors provided with a secondary air supply arrangement (Fig. 6) at the main iet 2 .the pipes ande may be combined into one pipe n which on one side communicates with the atmosphere through a restriction m and on the other side supplies the necessary secondary air to the main jet.

'I'he invention is' not limited to the particular construction of the control device shown in the drawings. If necessary further connection may be opened and. closed by the control device.

1. In a control mechanism of the throttle for carburetors of internal combustion engines of the kind where the throttle is operated by an adjusting device worked by the pedal in such a manner that the position of the throttle is made dependconnection between the pedal and lever of said cock, a iirst pipe connection between the upper space of the cylinder and the cock to establish communication with the atmosphere and a restricted second pipe connection between the lower space of the cylinder and the cock and a pipe connection between cock and throttle chamber to establish a through communication according to the adjusting of the plug cock, and two additional pipe connections between the second pipe connection and the cock adapted to establish communication with the atmosphere, one of these two connections being provided with a restricting device and restricted connection between .the ilrst and second pipe connections.

2. In a. mechanism according to claim 1 for the start with a cold motor, the combination with an independently operated auxiliary device comprising a' cylinder having a spr and an air inlet in said cylinder and, a restricted pipe connection with the first pipe connection.

3. In a mechanism according to claim 1 adapted to work with carburetors o! an oldei type the combination with an open cylinder attached to the stuiling box of the cylinder having a spring controlled piston, a piston fitting this open cylinder and provided on the piston rod o! the cylinder having the spring controlled piston, an air ccnduit communicating with the closed space of said open cylinder having a restricted outlet to the atmosphere and a pipe connection branched off said air conduit and communicating with the air space of the ilcat chamber of the carburetor.'

111g controlled piston 4. In a mechanism according to claim 1 adaptedto carburetors operating with secondary air for the main jet, two o! the branch pipes (f, e) from the chamber (A) below the piston are combined into one pipe which on one side is connected to the atmosphere through a damper and on the other side supplies the necessary secondary air to the main' jet (2).-

5. Mechanism according to claim 1 wherein the i plug cock' connects the suction pipe with the lower cylinder space, and the iirst pipe connection communicates with the atmosphere and the two auxar connections are closed when the throttle is inse sing condition. y

Mechanism according to claim 1 wherein the plug cock keeps the n on restricted auxiliary connection and the restricted second connection closed andV the restricted auxiliary connection communicateswith the atmosphere and the first connection communicates in a restricted manner with the throttle chamber when the pedal is in a depressedcondition.

7. Mechanism according to claim 1 wherein the plug cock keeps the two auxiliary connections in comm ication with the atmosphere and the rst Aconn tion in' communication with the throttle chamber in a non restricted manner to abolish the eiIect of the restricted auxiliary connection when the pedal is fully depressed.

` HANS-EBERHARD JAcoBY.

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