US2332440A - Internal combustion engine - Google Patents

Description

Qct. -19, 1943. G, R. E RICSON INTERNAL COMBUSTION ENGINE Original, FiiedMay 4, 1935 5 2 W.. 6 9 .w a .2 H1 M 5 4 2 2 Patented Get. 19, 1943 INTERNAL COMBUSTION ENGINE George R. Ericson, St. Louis, Mo., assignor to Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Original application May 4, 1935, Serial No. 19.842, now Patent No. 2,209,329, dated July 30, 1940. Divided and this application May 22, 1940, Serial No. 336,663

5 Claims.

This invention relates to internal combustion engines, and more particularly to devices for controlling the quantity of fuel mixture which may be introduced into the cylinders under certain conditions.-

It is well known that the power, speed and efficiency of engines may be increased by increasing the compression ratio, but the degree to which the ratio can be increased is limited by the tendency of the fuel mixtures to detonate or knock. Such detonation is a well known problem in modern high compression engines, and special fuels have been used for the purpose of reducing the tendency to detonate. With the use of such fuels the compression ratio of an engine can be slightly increased without any greater detonation than would have occurred with the same engine and with the slightly lower compression ratio with the use of ordinary fuel. But even with the best non-detonating fuels the compression ratio cannot be satisfactorily increased to the point of highest efficiency, and present day engines are designed with the idea of compromising between reasonable freedom from detonation and reasonably high efiiciency. Of course, the type of fuel to be used must also be taken into consideration, because anti-knock fuels are expensive, and the user of an automobile may prefer to use the cheaper straight fuels.

I 'he objectionable detonation occurs only during certain special driving conditions, such as hill climbing at low speed, and acceleration. These conditions probably obtain during less than five percent of the time in the normal operation of an automobile. When the engine is being operated at high speeds, even when the throttle valve is wide open, the tendency to detonation is materially reduced by the fact that the carburetor and the fuel mixture inlet valve ports present such restrictions as to prevent the admission of full charges to the cylinders, so that the charges are not so highly compressed prior to ignition, and therefore, are not so likely to detonate.

I have found that detonation occurs more readily when the engine is hot, probably due to the fact that the expanding effect of the heat on the fuel mixture increases the'compression, so that an engine will operate satisfactorily on a much higher compression ratio when the temperature is low than would be so under high temperature conditions.

Another problem in the design of the internal combustion engine is the proper vaporization and distribution of the fuel during low speed operation, particularly at low temperatures. When the throttle is open and the engine speedis low, substantialy quartities of liquid fuel are discharged into the intake manifold and if there is neither sufficient heat nor velocity of the air stream to vaporize this fuel, the distribution will be uneven and the operation of the engine will be very unsatisfactory.

Another difficulty which occurs in the operation of automotive internal combustion engines in that such devices as Windshield wipers, fuel supply device, and brake boosters are frequently dependent on the suction in the intake manifold for motive power, and when the throttle is opened wide at low speeds, these devices fail to operate.

It is an object of this invention to. prevent the introduction-of a sufiicient charge to the cylinders to cause detonation without substantially restricting the supply of mixture to the engine under conditions which would not cause detonation.

It is a further object of this invention to provide a device for restricting the flow of fuel mixture to the cylinders when the throttle is not in closed position and when the speed of the engine is low.

It is a further object of this invention to provide a device for maintaining a substantial predetermined vacuum in the intake manifold at all times during the operation of the engine under its own power without interfering with the flow of the mixture to the cylinder whenever, due to the closing of the throttle or due to the high speed at which the engine is being operated,

such predetermined vacuum exists in the manifold.

It is a further object of this invention to provide a device of the character described in the preceding paragraph and having means forvarying the restricting effect thereof in accordance with the temperature.

It is a further object of this invention to provide a device which will improve the vaporization and distribution of fuel in starting and in low temperature and wide open throttle conditions.

It is a further object of this invention to provide a device which will insure the maintenance of at least a predetermined degree of suction in the intake manifold whenever the engine is operating under its own power, so as to insure the proper operation of the windshield wiper, brake booster, and other suction'operated accessories.

Other objects of this invention will appear from the following description and accompany- 1935, issued as Patent No. 2,209,329 on July 1940.

The reference numeral indicates the intake manifold of an internal combustion engine. This manifold, if desired, may be provided with a heating device such as the exhaust jacket 2, although with the use of my invention it is not necessary'to apply as much heat to the mixture as would otherwise be necessary.

A conventional carburetor 3. is attached to the intake manifold or exhaust jacket by means of suitable studs or bolts 4. A flange member 5 having a downwardly extending sleeve 6 formed thereon is mounted between the bottom flange of the carburetor and the upper flange 1 of the intake manifold. It will be noted that the carburetor shown is of the downdraft type but the use of this type of carburetor is not in all respects essential to my invention.

The carburetor may be of any suitable type but preferably comprises a constant level chamber 8 in which the level of fuel is maintained by float 9 and a mixing conduit generally indicated by the reference numeral l and having a choke valve H and throttle valve l2, fuel being supplied to the mixing conduit from the constant level chamber by means of the main nozzle l3 and low speed nozzle I4, the construction and operation of which are well known to the art. It will be noted that the throttle valve is pivotally mounted in the walls of the mixing conduit by means of the shaft I and adapted to be manually operated and that the choke valve is pivotally mounted in the air inlet by means of the shaft l6 which may be operated either manually or automatically.

A windshield wiper 20 shown on a reduced scale is connected to the intake manifold I by means of a tube 2| so that the wiper may be operated by suction developed in the manifold. The tube 2| is connected to the manifold by means of a lit-- ting 22 which is also provided with a connection 23 which leads to the brake booster, vacuum tank,

and any other suction operated accessories. The construction and operation of these are well konwn, and since they are not necessary party of my invention, they are not shown.

The sleeve 6 extends downwardly thru the riser 25 which leads to the inlet manifold in a manner similar to that shown and described in the Bicknell Patent #1,994,011 issued March 12th, 1935. It differs from the Bicknell structure, however, in that it is not open and unobstructed but is provided with an inverted poppet valve 26 attached to a vertical shaft 21 which is slidably mounted in a guide 28 in the center of the sleeve. The guide 28 is carried by struts 28' which are attached to the walls of the sleeve and to the ide 28.

The valve 26 is operated by a piston 38 slidably mounted in the cylinder 3|, the upper end of which is connected to the intake manifold by means of a. tube 32. The effective capacity of the suction connection 32 is adjusted by means of a valve 33 provided with a head 34 having a screw driver slot for manual adjustment, a spring 35 or other locking device is provided to keep the valve in adjusted position. A compression spring 36 is mounted in the cylinder 30 and normally tends to hold the piston in the lower position as indicated.

The upper end of spring 36 is attached to an adjustment rod 31 for the purpose of varying its length and thereby its pressure. The rod v3! is provided with grooves 38 for coincidence with the ball detent 39 and may be positioned manually or by any suitable means, such as-a Bowden wire or linkage (not shown) from the dash board thru rocker arm 40 and attached at 4|. The piston 30 is connected by means of a link 42 to a lever 43 which is fixedly mounted on a rotatable shaft 44. The shaft 44 extends from the outside of the flange 5 at which point it is connected to the lever 43 to the inside of the same flange where it terminates in a recess 45 and is rigidly attached to a lever 46 which i connected by means of a link 41 to the shaft 21. It will be noted that the lever 43 is longer than lever 46, so that the diameter of the piston 30 need not be excessive.

Mounted on the exhaust jacket 2 is a bracket 48 which carries a short shaft 49. The shaft 49 is provided with a slit 50 in which is fixed the inner end of a thermostatic coil 5|. The outer end 52 of the coil projects over an extension of the pin 53 which serves as a pivot connection between link 42 and lever 43 so that when the temperature is high the coil 5|, tending to rotate in a clockwise direction will add additional resistance to the opening of valve 26. It will be understood'that the coil 5| may be a conventional bi-metallic thermostatic coil constructed and arranged to rotate in a clockwise direction when the temperature is increased in a manner well known in the art. The coil end 52 may be slitted if desired so that it may rest on the opposite ends of the pin 53, the lever 43, and the link 42 being located between the prongs of the fork.

While the relative strengths of the spring 36 and the coil 5| may be varied as desired to suit the requirement of a particular type of engine, I prefer to construct the spring 36 in such a manner as to provide sufficient resistance to the opening of the valve during operation in the lower ranges of temperature to insure vaporization of the mixture in accordance with the method outlined in my previously filed application #676,087 filed June 16th, 1933 now Patent No. 2,093,960, while in the higher ranges of temperature wherein detonation becomes more pronounced the additional resistance to the opening of the valve is provided as required by the clockwise rotation or winding of the coil 5|.

It will be understood that in the use of present day fuels which vary greatly in their anti-knock qualities, means for adjustment of the resistance to valve opening to compensate for these variations in fuel is necessary. I prefer to do this by the adjustment of spring 36 in a manner heretofore described. For fuels having high antiknock qualities the device is adjusted to the position shown in the drawing, in which the restricting effect of the valve 26 is small. For fuels having lower anti-knock qualities, more pressure is added.

The diameter of the piston 38 and cylinder 3| may be varied in accordance with the relative lengths of the levers 43 and 46 and the diameter of the valve 26, but I prefer to construct and arrange the relative proportions of these members together with the strength of the spring 36 and the pressure adjusting device so that a suction of lb. per sq. in. to 3 lbs. per sq. in. existing in the manifold will be suflicient to cause the opening of the valve 26 to such a point that it will not interfere with the flow of fuel mixture into the manifold.

The relative sizes of the parts indicated in the drawings should not be construed as a limitation, but merely as an indication of the relative sizes of parts in one type of device which has been successfully operated.

In operation,-assuming the temperature to be low, the valve 26 is held in closed position by the spring 36. When the engine is cranked suction would be applied not only to the piston 36 thru the pipe 32 but also to the head of thevalve 26 thereby causing a slight opening of the valve to permit the transmission of suction to operate the carburetor. Drops of liquid fuel falling on the head of the valve 26 are quickly vaporized by the air stream which attains a high velocity as it flows thru the crack between the lower end of the sleeve 6 and the slightly opened valve thereby securing better distribution and vaporization of the mixture. When'the engine starts to run under its own power if the throttle valve is open to a substantial extent, the valve 26 will remain in a.

nearly closed position thereby securing excellent vaporization. -If the throttle valve is closed, a very high suction would be built up in the manifold suflicient to draw the piston 36 to its uppermost position and open the valve 26 to a point at which it will not interfere with the flow of fuel mixture to the engine. It will be understood, of

course, that the valve 26 is not capable of improving the vaporization under these conditions but it is not necessary that it should do so because when the throttle is in closed position, the air stream attains a high velocity around its edges so that the fuel is efliciently vaporized.

After the engine has'been thoroughly warmed up, the heat responsive device is eifected by the heat of the exhaust manifold or jacket and its tendency to assist the action of the spring 36 is increased so that if the throttle valve I2 is held in open position with the engine operating at low speed, the valve 26 is caused to present a substantial restriction to the flow of mixture into the manifold so that the cylinders are not filled with predetermined pressure for which the valve is set.. This tends to reduce the restricting effect of the valve 26, and at maximum speeds eliminates it altogether, it being noted that the pressure of the atmosphere acts on the lower end of theplston while the upper end of the piston is aflected by ing degrees as determined bythe rate of flow. The popp t valve thus functions to direct the mixture stream evenly through the branched portions of the manifold.

It will be seen that I have provided a device which is capable of insuring the maintainance of at least a predetermined vacuum in the manifold under all conditions of operation so. that the compression ratio may be increased without increasing detonation'and so that the windshield wiper and other vacuum operated accessories will be kept in operation whenever the engine is a running under its own power.

5 In certain installations it may be desirable to provide some means of bypassing the valve 26 or preventing its absolute closing. For instance if the inlet and exhaust valves of the engine do hot seat properly it may be incapable of produc- 10 ing any substantial vacuum while it is being cranked-although it may run fairly well under its own power.

would be no means of starting the engine. I,

accordingly, provide one or.more small openings 53 which do not have any appreciable effect on the operation of the engine under its own power but which will permit the starting of the engine under the above described condition.

The invention is not limited to the structure shown but may be modified in various respects as will occur to those skilled in the art, and the exclusive use of all such modifications as come templated.

I claim: 7 l. The method of preventing detonation and ,improving distribution in internal combustion engines which comprises manually controlling the supply of fuel mixture for low speed operation, automatically restricting the flow of fuel mixture to the engine while the engine is being accelerated by elimination of said manual restriction, and utilizing the forces developed by the increase in engine speed to relieve said automatic restriction as the speed of the engine increases. 1 I

2. The method of operating an internal combustion engine which comprises restricting a mixture admission port of the -manifold when the engine speed is low and eliminating the restriction of said opening when a predetermined manifold vacuum is exceeded.

3. The method of operating an internal combustion engine which comprises manually regulating the effective area of a mixture passageway leading to the engine, yieldably restricting the flow of mixture to said engine and using the static suction developed in the mixture passageway to overcome the yieldable restriction when the engine speed increases to a predetermined rate.

a 4. The method of operating an internal combustion engine which comprises manually and automatically regulating the sup ly of combus'tible mixture thereto, delivering mixture to the engine through a passageway of limitedsize subject to said manual control but independent of said automatic control and operating the automatic control to increase the flow of mixture j to the engine only when apredetermined speed has been reached or exceeded, and substantially eliminating said restriction when the maximum leading to the engin yieldably restricting the flow of mixture to said engine, usingthe suction developed in the mixture passageway to overcome the yieldable restrictionwhen the engine ther varying said restriction in accordance with temperature.

- GEORGIR. $810808.

Under such conditions there.

within the scope of the appended claims is conspeed increases to a predetermined rate, and furx

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