US2375883A - Internal combustion engine charge forming apparatus - Google Patents

Description

May 15, 1945. R. M. ANDERSON 2,375,883

INTERNAL-COMBUSTION ENGINE CHARGE FORMING APPARATUS Original Filed June 16, 1939 24A: Mini/0M 2:114:15! Mai/a IM "My 01:

atented May i5, 1945 INTERNAL COMBUSTION ENGINE CHARGE FORMING APPARATUS Raymond- M. Anderson, Detroit, llfich, assignor to Evans Products Company, Detroit, Mich, a

corporation of Delaware Original application June 16, 1939, Serial No.

279,394, now Iatent No. 2,323,639, dated July 6, 1943. Divided and this application November 20, 1942. Serial No. 466.275

14 Claims. (o1. 123-119) The present invention relates to internal combustion charge forming apparatus .and this application is a division of applicants copending application Serial No. 279,394, filed June 16, 1939, now Patent Number 2,323,639 for Internal combustion engine charge forming apparatus and relates to such apparatus and particularly to devices combined with an engine to reduce detonation, or knocking by admitting an anti-knock fluid such as exhaust gas under certain conditions, such as under heavy loads,

Various other charge forming features and combinations and such anti-knock devices are claimed in this parent application, but the antiknock apparatus or devices to supply exhaust gas only at full load conditions are claimed therein in combination with a, particular engine fuel supplying means, namely, means to supply the intake conduit with a high temperature super rich mixture of oil and a small part of the total air supply, whereas the invention of this divisional application relates to such anti-knock devices per se or in combination with ordinary engines without regard to such special fuel supplying means.

The objects of this invention are to provide improved internal combustion engine charge apparatusincluding simple and dependable means to prevent or reduce knocking of the internal combustion engine under heavy load conditions. Other and more specific objects, features and advantages will be apparent from the following specification, the corresponding drawing, and the appended claims.

In the drawing, in which like numerals are used to designate like parts in the several views throughout;

Figure 1 is a general view showing in elevation part of an embodiment of the whole specific charge forming and regulating apparatus of the above identified parent application as it appears installed on or applied to a conventional, present-day, automotive vehicle, gasolineengine, with conduit 39 shown diagrammatically and showing a first form or embodiment of my anti-knock device applied to such an engine;

Figure 2 is a wholly diagrammatic and spread out view of some of the major portions of the whole specific charge forming and regulating apparatus of my above identified parent application and corresponding to Figure 1, this view showing generally 01' schematically the epnnections between the several parts but vnotaccu- ,rately showing relative positions or th*relative vertical levels of the parts and also showing in more detail the first embodiment of my antiknock device as applied;

Figure 3 is a partly diagrammatic view showing a modified form or a second embodiment of. an installed anti-detonation unit according to my invention; and

Figure 4 is a sectional View of still another modified form or a third embodiment of an antidetonation unit, according to my invention.

In general, the anti-detonation unit of this invention may be applied to or used in combination with any of various sorts of internal combustion engines for vehicle, marine or stationary use having spark ignition, exhaust and an intake manifold or conduit means with a carburetor or the like to supply any desired fuel in the proper mixture ratios into this intake conduit and more particularly to conventional or present-day types of gasoline engines, such as are now commonly used in trucks and passenger automobiles. In order to completely disclose one particular application of my improved anti-detonation apparatus as specifically disclosed in parent case and to give a better understanding of its use and interrelation and combination with the other parts of an internal combustion engine, I have included herein thoseportions of the specification and drawing of my above identified parent application, which relate more directly to my anti-knock device, and have briefly summarized the rest of the equipment of the parent application, yet I intend to include by reference herein the balance of this parent application, in order to give the desired and complete understanding of this specific embodiment.

However, as indicated above, it is to be understood that this division application is not .intended to be in any wise limited to this particular type of engine or fuel feeding system since it will be generally ap arent and will appe r from the present application that the improved antidetonation device of the present invention may be of general utility and used in combination with various conventional sorts of internal combustion engines, as indicated above.

As shown as a whole in Figure 1 and as shown,

schematically in Figure 20, the improved charge forming and regulating apparatus is applied to a conventional type asoline engine 2 having an induction intake conduit including 'the intake manifold 3 and an exhaust conduit including the exhaust manifold 4. The intake conduit includes a carburetor unit I which, as illustrated herein, maybe of the down draft type. The engine is provided with the usual air cleaner H2 mounted above the carburetor. A compact, fiat, vaporizer-heater unit or heat exchanger 5 is jacketed and heated by exhaust gases conveyed thereto from the exhaust manifold by a pipe it, the used exhaust gases being carried back to the exhaust conduit by pipe i. Pipes 6 an i may be used to support this vaporizer-heater unit.

The main unheated air-fuel mixture is carried from the carburetor unit I to the heater by horizontal pipe connection 8, and the hot super rich mixture is conducted from the heater to the carburetor mixing chamber by the slightly lower horizontal pipe connection 9, which is preferably made of aluminum, aluminum alloys or the like, as discussed hereinafter.

In the present invention, the major part of the engine's air supply is sucked down through the intake conduit (comprising the riser, the mixing chamber, and the intake manifold) in the usual fashion, while a small proportion (preferably about 5% and less than of the total air supply is drawn through a separate passage, the hot mixture-contacting portions of which are all of aluminum or the like, and which includes connections 8 and 9 and the substantially horizontal, tortuous, mixture-heating passage in the heater 5.

In general, I have provided a suitable Venturi means 65 located near the entrance 8 to this passage, together with suitable light and heavy fuel jets (not shown) to supply either light or heavy fuel from the adjacent two reservoirs of a suitable multi-fuel carburetor I, thus either of the two fuels is metered and mixed with the air stream in passage 8, and this super rich mixture is heated to a. high temperature so that the sprayed fuel is partly gasified, partly vaporized, and the balance finely divided. For the sake of simplicity, this condition is hereinafter referred to as vaporized.

It is believed impractical to thoroughly gasify all of the oil or to really crack all Of the heavy hydrocarbons in an apparatus of this type. Only enough air is used in this rich mixture to effectively carry the fuel and to hold enough heat to effectively vaporize the main fuel supply and to keep it in this condition in the intake manifold. It is important that only a small portion of the total air supply is heated to a pre-dctermined temperature so that the volumetric efficiency of the engine will not be materially reduced. Such a reduction in volumetric efiiciency, with its attendant decrease in power and torque, would occur if it were attempted to heat sufficiently all of the engines air supply to permit the use of'low grade fuel, or if even a small proportion of the total air were heated to too high a temperature. Also, too high a temperature, tending to distill or crack the heavy fuel, will produce carbon and gum deposits; while, on the other hand, too low a temperature will cause crankcase dilution from the unvaporized globules of heavy fuel.

It may be noted in connection with the use of heavy fuel, such as oil, in a conventional gasoline type engine, that it has been previously proposed to heat the liquid oil (without any appreciable quantity of air) in a small passage or elsewhere and then to spray it into the intake conduit where it is supposed to be vaporized and mixed in a venturi or the like. Such systems are impractical, if not commercially impossible,

since it is not possible'to get enough heat into the liquid oil itself so that it will vaporize sufficiently when discharged into the intake mixing chamber. On the other hand, if sufficient heat is added to this liquid oil so that it is partly gasifled or vaporized in its heating passage, then the metering will vary widely with small temperature changes and as alternate charges of liquid and vaporized oil come along the passage.

Any sudden increases in the richness of the fuel mixture from the vaporizer-heater 5, and particularly the collection or trapping of a pool of liquid fuel which is later sucked into the intake conduit at a period of high vacuum (for example, when the throttle is suddenly opened), are highly objectionable since they cause smoking, carbon and gummy deposits, tend to choke the engine, to produce crankcase dilution, and reduce economy. Hence the uniform vaporization and supply of the rich, heated air-fuel mixture and the provision of a proper vaporizer-heater and connections therefor which have no traps or the like, are particularly desirable.

As is well known, the actual temperatures of the exhaust gas in the manifold of ordinary gas oline engines vary within wide limits (about 600 degrees F. to nearly 1450 degrees F.) under different speed and load conditions so that the amount of heat available to the exhaust heater for the super rich air-fuel mixture varies widely. Accordingly, it is important that the quantity of exhaust gas made available to the heater unit be regulated not only in accordance with temperature but in accordance with engine speedload conditions, which may be represented by exhaust gas flow rate. If the rich heated mixture of air and heavy fuel is not heated to a high enough temperature, there will be excessive and objectionable crankcase dilution due to lack of vaporization of the heavy fuel condensation.

Also, too low a temperature is apt to cause smoking. O n the other hand, too high a temperature for this mixture will reduce the volumetric efficiency, as noted above. It has been found that a mixture temperature of about 400 degrees F. is best when using oil or similar heavy fuels, although this temperature may be varied from about 375 to 500 degrees F.- When using gasoline, even the cheaper, poorer grade with low octane rating, in this super rich heated mixture, good results may be obtained with lower mixture temperatures. For example, a temperature as low as 280 degrees F. can be used, with best results at about 350 degrees F. However, the above mentioned 400 degrees F. temperature will be found satisfactory for either type of fuel.

It has been found that the better distribution obtained because of the predetermined amount of heat added with this rich heated mixture more than offsets the expected slight decrease in volumetric efliciency so that higher torques have been obtained. Also, this better distribution tends to reduce detonation.

Another reason why it is important to regulate the temperature of the mixture in the vaporizer-heater unit 5 is that it is necessary in order to secure proper over-all air-fuel ratios under different load conditions and the corresponding temperatures of the exhaust gas in the exhaust manifold 4. For example, an increase in temperature of the vaporizer-heater will cause an expansion of the air in the mixture passage therein and an even greater expansion of the.

fuel particles, which will tend to reduce the vacuum in this passage and thus reduce the suction on the main fuel jet (not shown here) so that the mixture will become leaner. The converse asvaasa will, oi course, occur if the temperature drops suddenly. "Thus it will be apparent that changes in temperature will affect the metering adversely and, accordingly, the over-all fuel ratio and the economy.

Referring again to the more specific, complete disclosure in the parent application, it will be apparent that the flow of the exhaust gas from the exhaust manifold Al to the exhaust pipe 93 may be all or in part diverted through a by-pass circuit consisting of a pipe connection it through the jacket surroundin the vaporizerheater 5, through connection il and pipe 2', this diversion being controlled by a suitable thermo statically regulated valve unit comprising the unbalanced valve 99, which is on a shaft which also carries the inertia weight wheel [Hi l carrying the ofiset and adjustable weight 103 to bias valve Q9 toward its closed or heating position, this weight it?) being secured in any one of sevadjusted positions by bolt 8% which may be received in one of several holes (not shown here). The valve 99 is also actuated toward open or closed position by a suitable bi-metallic element, as will be well understood in this art.

Referring further to Figure 1, the carburetor l is of the multi-fuel type and in addition to supplying either light or heavy fuel, such as gasoline or oil, to the intake to the vaporizer 5. This carburetor i also embodies means to suppor gasoline for acceleration, for idling, and for the conventional compensating flow. It Will be noted that these are always on gasoline and will operate concurrently with the main super rich air fuel mixture from the vaporizer which discharged into the throat of a multiple-Venturi set 58 through pipe 9. These more. detailed features will be seen more clearly in the incomplete schematic Figure 2 which also shows the exhaust gas inlet 53 and discharge fitting ll for the vaporizer 5, the conventional air cleaner M2, the entrance to the intake conduit above the carburetor, the conventional choke at and, above the choke, but below the air cleaner, the pipe i3 3 to supply air to a special form of economizer its, the pipe '53 to supply air to the venturi, the entrance pipe 8 and the pipe M5 to bleed air to the non-illustrated but conventional gasoline idling system, which as usual supplies the idling gasoline into the manifold adjacent the throttle plate H3 through conduit lfiti,

Just below the choke and upstream from the multiple Venturi set which includes the parts 68, Sill-A and 62), l have shown the conduit means H673 to inject gasoline for acceleration and this conduit i6? is periodically supplied with gasoline by wholly conventional means which are well known in present day carburetors and include a suitably actuated pump supply by gasoline from the reservoir in the two bowl carburetor i. This metered oil or metered gasoline is supplied through jets from one of the two valves in carburetor units l through conduit 63-455 to the Venturi unit 85.

The suitably metered compensating flow of gasoline is led into the Venturi set 69 by conduit means i 55.

It will also be noted that Figure 2 shows certain details of the economizer l28, including pipe wt, to supply vacuum to actuate the piston valve 929 which controls the admission of -air into the intake manifold through the annular passage Bi. and the ports M2. This feature in particular may, of course, be eliminated, if desired, and in general will be understood as emphasized above that the above described details or specific parts are not to be considered as part of this invention, except insofar as they supply one specific installation.

Referring now to the operation of this particular embodiment, as shown in the parent application, it will be seen that for starting, as disclosed in the parent application, I have provided entirely the conventional carburetor units or parts, including an accelerator pump, the idling system and a compensator metering system and jet to supply the intake manifold or its mixing chamber with these auxiliary flows of gasoline concurrently with a supply of the super rich mixture of a small part of the air with either oil or gasoline as delivered into the mixing chamber venturi 69 by pipe t. Obviously, these particular details are not essential to the present invention.

In order to reduce detonation or knocking at high load and speed conditions, particularly where operating temperatures are high, a novel anti-detonation unit (of which three forms are hereinafter described) may be employed, which may admit a small amount of exhaust gas into the intake manifold at the time of detonating conditions under the control. of the throttle itself or in response to exhaust manifold and intake manifold pressures, which are a measure of the engine load-speed conditions.

One form of anti-detonation unit is shown more or less schematically in Figures 1 and 2 in which the housing l'lll has a narrow valve guiding portion ll i, the enlarged upper end of which-is connected by pipe H2 to the intake throttle, and

which also has the pipe or conduit ll?) connect-' ertia damped to prevent flutter. When the valve is closed it will be up against the valve seat ill and close off communication from the exhaust connection H3. Generally speaking, this valve unit is either on or off, and it will be apparent that the piston I15 isactuated by and is responsive to the algebraic sum of the exhaust pressure and the intake manifold pressure when the valve l'l l is off its seat ill; that is, the exhaust pressure is aided by the weight of the valve in holding it open while the intake manifold vacuum is tending to lift the piston H5 up to close the valve. No springs or the like are used for biasing a valve of this type since it would be difficult, if not impossible, to make a spring which would stand up under the very high temperature and hard service encountered in a unit of this type. It will be apparent that by properly proportioning the weight of the valve, the piston area, and the size of the connections, this valve can be made to open only at full load conditions of the engine; and it will be responsive to the load-speed conditions of the engine since at full load conditionsthe intake manifold vacuum is quite low, and the exhaust pressure is high. In addition, the exhaust pressure will increase with the speed of the engine. Pipe connections I12 and H3 and the valve housing I10 itself will cool the exhaust gas which is carried from the exhaust manifold to the intake manifold to reduce the loss of volumetric efficiency due to the highly expanded high temperature exhaust gases. If additional cooling is desired, it will be obvious that a suitable heat exchanger or cooler can be added to this unit.

It will be apparent that the heavy valve l'l i will normally beheld on its seat Ill to shut on any exhaust gas flow by the intake manifold vacuum action on the piston I15 and overcoming the weight of parts I75 and I'M.

With a valve unit of the types disclosed herein, it has been found desirable to admit inert gas up to about of the volume of the air-fuel charge for full or nearly full loads only. This will eliminate or greatly reduce the knocking which is more of a problem when the hot engine is runnin and the upper end of this housin 210 has an opening for the valve actuatin rod 28I'which carries a pivoted member 280 which contains a slot 279 cooperating with a pin 218 which is fixed on or with respect to the throttle I I3. This pinand-slot lost motion connection is so arranged that the valve is lifted from its'seat only at or near full load throttle openings so that exhaust gas will be admitted only at these conditions when detonation would be apt to occur.

A preferred form of this anti-detonation unit is shown in Figure 4 in which the valve housing 318, which may be made in the form of a simple casting or otherwise, is tapped for the exhaust manifold pipe or connection 313 and the intake manifold pipe or connection 312. The upper end of the valve housing 310 is closed by plate 382 which may be secured on suitable shoulders by the upper edges of the housing being peaned over or the like. This plate is vented to atmosphere at 316, and a slight amount of gas may leak through this vent 316. The plate or disk valve element 376 may be circular and slightly smaller in diameter than the circular housing 310 so that it has a loose or sloppy fit therein. The disk valve 314 need only be heavy enough to insure its seating when the engine is being started. When in its normal low position resting on the valve seat 3", it will be apparent that this disk valve 314 closes off communication to the central It will be apparent that when.

of the valve itself. As noted above in connecthe disk valve 314 is in its upper or open position,

it is subjected to the value of the exhaust pressure minus the value of the manifold suction and, in addition, to its own slight weight. Note, however, that when the valve is opened, the resultant of these two pressures acts over its whole area.

The anti-detonation units of both Figures 3 and 4 have one advantage over the unit of Figure 2 in that they will not be open when the engine is first started and thus permit a flow of exhaust as into the intake manifold, which will make starting more diilicult. It is also noted that the units of Figures 3 and 4 may include a cooling fluid, if desired.

Although the foregoing description is necessarily of a detailed character, in order that the invention 'may be completely set forth, it is to be understood that the specified terminology is not intended to be restrictive or confining and that various omissions and rearrangements or modifications of parts may be employed without departing from the scope or spirit of the invention as claimed herein.

I claim:

1-. In combination, an internal combustion engine embodying an exhaust conduit and intake conduit having fuel supply means and anti-knock means admitting a small amount of exhaust gas from the exhaust conduit to the intake conduit only at full load conditions and comprising a gravity biased, normally closed valve arranged to hold itself closed when the engine is not running, a valve housing, and connections so that said valve is responsive to the intake vacuum and the exhaust pressure opposing each other.

2. In combination, an internal combustion engine embodying an exhaust conduit and intake.

conduit having fuel supply means and anti-knock means admitting a small amount of exhaust conduit to the intake conduit only at full load conditions and comprising a heavy gravity biased and inertia damped valve element, a valve housing, and connections so that said valve is responsive to the intake vacuum and the exhaust pressure acting in opposition.

3. For use with an internal combustion engine embodying an exhaust conduit, an intake conduit, and a throttle, an anti-detonation unit for admitting a small amount of exhaust gas from the exhaust conduit to the intake conduit during knocking conditions and including connections and a normally closed, gravity biased valve, and means including a 10st motion connection connecting said valve to be operated by said throttle.

4. For use with an internal combustion engine having an exhaust conduit and an intake conduit, an anti-detonation unit for admitting a small quantity of exhaust gas from the exhaust conduit to the intake conduit during knocking conditions and comprising a heavy, inertia damped valve element gravity biased toward open position and means to hold said valve closed during normal running conditions responsive to and actuated by the intake conduit vacuum.

5. For use with an internal combustion en-,

. tion connecting said valve to be opened by said throttle only when moved to its substantially fully open position.

6. For use with an internal combustion engine embodying an exhaust conduit and an intake conduit, an anti-detonation unit for admitting a small amount of exhaust gas from the exhaust conduit to the intake conduit only at full load conditions and including cooling connections and a normally closed, gravity biased valve responsive to and actuated by th intake vacuum and the exhaust pressure opposing each other.

7. For use with an internal combustion engine having an exhaust conduit and an intake conduit with a throttle, an anti-detonation unit for admitting a small quantity of exhaust gas into the intake conduit beyond the throttle comprising an on-ofi type valve and means tOhOld said valve closed during normal running and to open it only under heavy load conditions.

8. In combination with an internal combustion engine having an exhaust conduit and an intake conduit with a throttle therein, anti-detonation means connected to admit a small quantity of exhaust gas into the intake conduit after the throttle during knocking conditions comprising an on-ofi? type, heavy, inertia damped and gravity biased valve and means to sold said valve closed during normal running conditions and to open it only under heavy load conditions.

9. For use with an internal combustion engine having an exhaust conduit and an induction intake conduit with a throttle therein, an antiknock unit to admit a small quantity of exhaust gas into the intake conduit beyond the throttle only during knocking conditions comprising an on or oil type heavy valve, inertia damped and gravity biased to closed position so that it is closed when the engine is not running and during normal running conditions and means to open said valve only during full load conditions.

10. For use with an internal combustion engine having an exhaust conduit and an induction intake conduit, an anti-detonation unit to admit a small quantity of exhaust gas into the intake conduit under heavy load conditions comprising a casing having valve guide means therein and an upwardly facing valve seat therein, a large area free disk type valve reciprocable in said casing, having a' loose fit in said casing and its guide ,means, and gravity biased to rest on and close off said valve seat when the engine is not running and during normal running conditions, said casing being vented to atmosphere on the other side of said valve, the space within said valve seat being connected to the intake conduit and said casing having. means to subject the larger area annular outer portion of the same under 'side of the valve to the exhaust pressure,

whereby, when closed, the smaller area of, the inner portion of the area of the under face of the valve is subject to the intake vacuum and the larger area of the outer portion of the area of the under face is subject to the exhaust pressure modified by the leakage from said loose fit and saidvent and, when open, the entire under face of the valve is subject to the algebraic sum of the intake and exhaust pressures modified by the leakage from said loose fit and said vent.

11. For use with an internal combustion engine having exhaust and induction intake conduits, an anti-detonation unit including a free reciprocating valve means biased to closed position when-the engine is not running and during normal running conditions, and means to actuate said valve to admit exhaust gas to said intake conduit only during heavy load conditions, including a piston area and connections to expose one part of said area ,to the intake vacuum when the valve is closed and to expose all of said area to the algebraic sum 0f these two pressures when the valve is open.

12. For use with an internal combustion engine having an exhaust conduit and an induction intake manifold, an anti-detonation unit, comprising an on or off type valve to admit an anti-knock substance into the intake manifold only during knocking conditions, and means to actuate said valve responsive to the intake manifold vacuum and the exhaust pressure acting in opposition.

13. For use with an internal combustion engine having an exhaust conduit and an induction intake conduit with a throttle therein comprising an anti-detonation unit comprising a valve casing having connections to the exhaust conduit and to the intake conduit beyond its throttle. means including on or off type valve therein to control the admission of'an anti-knock substance into the intake manifold beyond its throttle. and quick acting means to actuate said valve to hold it closed during normal running conditions and to open it only during heavy load conditions.

14. For use with an internal combustionengine having an exhaust conduit and an induction .intake manifold with a throttle, an anti-detonation unit for admitting a small quantity or exhaust gas into the intake manifold beyond the throttle during knocking conditions comprising passage means to connect to said exhaust conduit and to said intake manifold beyond the thottle, and control means in said passage means to prevent exhaust gas flow therethrough during all normal running conditions and to permit exhaust gas flow therethrough only during heavy load conditions.

' RAYMOND M. ANDERSON.

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