US2004093A - Thermostatically and suction controlled mixture temperature device - Google Patents

Description

June 11, 193.5. E. E. DEAN: ET L 2,004,093

THERMOSTATICALLY AND SUGTION'CONTROLLED MIXTURE TEMPERATURE DEVICE Filed Sept. 25, 1950 2 Shets-Sheet 1 C C/ward (F7 @9412,

June 11, 1935. E, DEAN r AL 2,004,093

THERMOSTATICALLY AND SUCTION CONTROLLED MIXTURE TEMPERATURE DEVICE Filed Sept. 25, 1930 2 Sheets-Sheet 2 0 1' C (er erry.

Patented June 11, 1935 UNITED STATES THERMOSTATICALLY AND SUCTION ,OON-

TROLLED MIXTURE TEMPERATURE pm VICE Edward E. Dean and one Carter Berry, Flint,

:Mich., assigncrs tp Marvel Carburetor Company, Flint, Mich, a corporation of Illinois Applicaticn fieptember 25, 1930, Serial N 0. 484,335

B QIaims. (01. 123- 122),

This invention relates to an improved manifold heat control for :carbureter-type internal combustionengines.

One' object of this invention is to produce a hot-spot in which the amount of exhaust heat used is thermostatically controlled and "in which the thermostat is responsive to mixture temperatures only."

Another object of this invention isto produce a thermostatic control for a hot-spot'capable of distinguishing between open throttle and part throttle operation of an engine, so asjto maintain.

the mixture temperature correct for openthrottle operation when the engine is in fact operating at open throttle and at the same time maintaining the correct mixture temperature for part throttle cperation whenthe engine is actually operating alI-YDQJIlithIOttIGJ A further object of this invention is to pro-, duce a thermostat capable of holding the temperature of the intake mixtureto within very close limits, and to do this inthe face of large variations in the temperature of the air'entering the carbureter.

No other temperature about an engine has so vital an effect "on its ture temperature. Experience indicates that the driving public expects anfengine' to perform well long before its cooling Water, lubricating oil, and radiator can be warmed up. An exhaust heated hot-spot heats upyeryquickIy and makes this possible. If the mixture is warmlenough so that the fuel is properly vaporized the engine will seem to perform nicely even when the other temperatures are far below normal. If th-e mixture is a little too cold, too much of the, fuel will be deposited on the wallsof the manifold as astream of liquid that cannotbe uniformly distributed. This will resultin poor acceleration, poor econoiny and inferior performance on the part of the engine. If themixture is too hot the engine'will lose in power, show an increased tendency toward detonation and not be able touse anormalarnount of accelerating gas. u a One of the difiiculties which previousinventors have met with in attempts to produce a thermostat responsive tomixture temperatures has been the fact that the engine requiresavery difierent temperature for best operationwhen working at pen throttle from that requiredfat light loads. The metal in-the hot-spot will inevitably have considerable heat capacity andcannotbe changed quickly from one temperature'to another; lithe mixture passe'sthrough the ho spawn a very slow rate, itwill pick up more 5 heat than it can performance as does mix when passing through quickly. If an engine is being driven at part throttle and the throttle is suddenly opened; the mixturetemperature will inevitably drop, or if the throttlefis suddenly closed, it will rise just as quickly. 'In the case of the engine most used in connection with thedevelopment of this invention, when the throttle was suddenly closed'at i000 R.P.' M.""full- -load, and a mixture temperature of F., the mixture rose to about 150. Repeated tests indicated that the engine would reproduce these results consistently in either direction. I 7

This inherent change in mixture temperatures is takenadvantage of, as it t'e'nds'to immediately establish temperatures required. The by-m'e'tal following very rapidlyany change injtemperatur'e' of the mixture will thereforern'aintain an this temperature, whether it be for partor wide open requirements. i i

It has been found experimentally that this inherent riseand fall of mixture temperatures due to going from partto full load and the reverse corresponds very closely with'that requiredfor good operation. It has also been foundthat the wideopen or power requirements are abo'ut 8 5 to degrees Fahrenheit. I

"If, therefore, we choose this temperature for powerwe'will* findthat' the part throttle temperatures 'will beabout'right; Y There is noobjection to a moderatelyhigh temperature of results areobtained' this way;

"The best solution seems to be to let the open throttlete'mper'ature be the controlling consideration'a'nd plan to use'a 'part throttle-temperature such that when changing quickly from-"closed to open"throttle operation the open throttle temperatiirewillbe'right. 1 It iswell understood among automotive engineers tIiat-the vacuum in the intake manifold will vary nversely with the loado'n the engin'eWIn.

other words "when the engine is operating under full Icad'th'e'intake manifold vacuum is very slightj'whileiat lightloads' 'it'may be as much as 19 or 2 0"iric hes of mercury. We have takenadvantage oithis in connection with ourthermostat. A diaphragm'is-placedin communication with the intake manifoldand arranged sothat it works against asprin'gf When the suction is heavy th'ispring will -be compressed. When the toitsoutermost'position? "In tueprere rrujrbrm of our present invention the valvelcontrblling the easiest gas supply ,to the hot-spot is not directly saunas either by suction islight the spring will push' the diaphragm mixture at part throttle. -Best the thermostat or by the intake manifold suction, but rather by an external source of power which is jointly controlled by these two. One way of accomplishing this is to have one of a pair of electrical contact points placed on the end of a strip of bi-metallic metal, and the other contact point placed so as to be influenced by the manifold suction. The idea is to have all of the exhaust gases used to heat the hot-spot when these points are separated and to have the exhaust cut off when electric contact is made. A more accurate under-' standing of the preferred form of our invention may be had by referring to the accompanying drawings. In all of the figures presented, the same number refers to the same part.

It is accordingly an object of this invention to provide a heat control system for heated intake manifolds wherein the mixturetherein is maintained at a constant temperature under given operating conditions and the temperature is varied over a predetermined range in response to variations in speed and load.

Other and further important objects of this invention will be apparent'from the disclosures in the specification and the accompanying drawmgs.

This invention (in a preferred form) is illustrated in the drawings and hereinafter more fully described.

On the drawings: 7

Figure l is an elevation of the exhaust and intake manifolding systems of an internal combustion engine incorporating one embodiment of the features of this invention.

V Figure 2 is a central section in the principal plane of Figure l.

Figure 3 is an enlarged section through the preferred form of temperature and pressure control elements as applied to the intake manifold.

Figure 4 is a section on the line IVIV of Figure 3 with parts in elevation. V

Figure 5 is a section on the line V-,V of Figure 4 with parts shown in elevation.

As shown on the drawings:

The manifolding arrangement chosen for illustrative purposes comprises an exhaust manifold if) having a central outstanding pocket ll containing a heat control valve operated by a lever i2. The valve comprises a baffle plate 13, rotatable to block the exhaust manifold, together with a segmental disc valve 14 controlling ports l5 in a partition forming a continuation of the exhaust passage about midway of the depth of the pocket II. The baffle plate l3 extends on either side of the disc valve M, the front part serving as a partitionbetween the two ports I5.

Ducts ifi and ports I5 to a juncture with a heating jacket l8 enveloping the T of an intake manifold IS. The manifold is fed by a riser 20 enveloped by an extension of the jacket I8 which jacket contains a partition 21 forming a continuation of the baffle plate 13. A conventionalized carbureter 22 is shown as feeding the riser, the upper part of the carbureter around the throttle valve 23 being formed as a acket 2e connecting the lower ends of the ducts i6 and 11. With this arrangement, when the exhaust control valve is in the heat on position of Figure 2, the exhaust gases from the left half of the exhaust manifold are diverted by the baffle plate l3 through the left port l5 into the duct 16, thence downwardly into the lower connecting jacket 24 and I up the duct ll to the right hand port U5 into the exhaust manifold again. Whenthe exhaust I! extend downwardly from the the operation'of the other forms of heat control since the invention lies in the control of the mixture temperature rather than in the heating means per se.

The temperature and pressure responsive ele- V ments of this invention are applied to an unjacketed portion of the intake manifold H] in the form of a housing indicated generally by the reference numeral 25. A bi-rnetal thermostatic strip 26 extends across the manifold; one end being anchored in an insulated taper plug 21 sealingly mounted in a boss 28, the other or free end carrying an electrical contact 29 and projecting into the housing 25 as shown in Figures 3 and 4. The position of the thermostatic strip as well as its insulated base, renders it sensitive only to mixture temperatures, since it is almost wholly in the mixture stream and the chamber 25 is also in communication with the mixture stream through the hole provided for the free end of the thermostat.

The second contact 38 cooperating with the thermostat contact 29 is adjustably mounted in a lever 3i pivoted at 32. The free end 33 of the lever is operatively engaged with a flexible diaphragm 3d clamped around its edges by a cover 35 in a suitable recess in the housing 25. This diaphragm is responsiveto intake manifold suctions, and inward displacement of the diaphragm, due to increased suction, serving to move the lever 35 to increase the initial separation of the electrical contact points 29 and 3!]. The cover 35 is provided with an atmospheric vent 36 which should be small enough so that in the event of diaphragm failure the resulting air leakage into the manifold will be restricted to a volume insufficient to materially affect the mixture proportioning.

The diaphragm bears against a guide plug 38 slidable in a pocket 39 in the housing, and is adapted to receive a calibrated spring at which acts to force the diaphragm outwardly, carrying the lever end 33 therewith.

An increase in mixture temperature, perhaps accompanied by a decrease in manifold suction, brings the contact points 29 and 30 together and a circuit is completed from a source of electrical energy 12 through a wire 43 to the coils of an electric magnet or solenoid M and thence by a wire 45 to the thermostat terminal and contact points 29 and 30 to a ground on the lever 3|, the ground return to the source of current being indicated by a wire is in Figure 1. The magnet or solenoid M is provided with a slidable armature t? which is directly connected to the heat control valve lever i2 by a link 48. The lever 52, link G8 and armature 51 are normally held in their upper or heat on position by a spring :13; the energization of the magnet or solenoid pulling down on the armature to turn the heatcontrol valve into the heat off position. The thermostatic responsiveness of a bi-metal strip is well known so that it will be evident that a low manifold mixture temperature, with correct initial adjustments of the adjustable contact members, will serve to maintain the normal separated position of the contact members, thus maintaining an open circuit under which circumstances the heat control valve l2 will be held in the heat on position by the spring 49.

This will be the normal position when the engine is not in operation or is operating at a temperature below that desired in the mixture flowing past the thermostatic member.

As the temperature begins to rise in the intake manifold the bi-metal thermostat will bend, bringing the contact members together when the desired temperature has been reached. At this point energy will flow through the completed electrical circuit, energizing the magnet or solenoid thus turning the heat control valve to the heat off position.

Since it has been found that engines under power require less heat than for part load or idling operation, themixture temperature control is designed to differentiate between part throttle and full power. This is accomplished by utilizing the variations in manifold suction to vary the relative position of the contact elements to require a greater degree of heat to close the same at the higher manifold depressions which exist under idling and part load conditions.

In the illustrated embodiment of the invention the lever follows the movement of the diaphragm, which is drawn inwardly by an increase in manifold depression, so that one of the contacts is moved away from the other. It will be evident that when the contacts are farthest apart due to the action of suction a greater temperature will be required to deflect the thermostatic member sufliciently to bring them together. Therefore, since higher temperatures are required for idling or part load conditions, the increased suction differential will move the diaphragm inwardly. In the illustrated form of the invention the spring 40 is so calibrated that when the temperature is required to increase it willyield to allow the diaphragm to move inwardly to the desired extent.

It will be evident from the foregoing that the mixture temperatures may be controlled within practical limits, as if the desirable temperature range is known for a given engine, it merely becomes a question of calibrating the contact movement.

It will thus be seen that we have invented an improved automatic heat control which maintains a predetermined temperature range in the intake mixture, which temperature is varied under varying conditions of load and speed.

We are aware that many changes may be made, and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and. we, therefore, do not purpose limiting the patent granted hereon, otherwise than necessitated by the prior art.

We claim as our invention:

1. An intake manifold heating system for internal combustion engines, comprising a heating jacket enveloping part of said manifold, a control valve governing the supply of heat to said heating jacket, a, solenoid for operating said control valve, and means for energizing said soleresponsive element for opening and closing said valve, .and means responsive to engine manifold suction for modifying the temperature range of said temperature responsive element, whereby to increase the operating temperature as the manifold suction increases.

3. An intake system for internal combustion engines, comprising means for heating the fuel and air mixture flowing through said intake system, a control valve governing the supply of heat to said heating means, a mixture temperature re-. sponsive element incorporating a variable temperature range for opening and closing said valve, and means responsive to the intake suction for increasing the effective temperature controlling said valve in proportion to increasing intake suction.

4. In combination, in an intake system for an internal combustion engine, a conduit for the fluids delivered to the engine, heating means for the fluids in said conduit, a control valve governing the supply of heat to said heating means and thermally sensitive mechanism associated with the fluids in said conduit for opening and closing increase the effective temperature with an increase in engine suction.

5. Incombination, in an intake system for an internal combustion engine, a conduit for the fluids delivered to the engine, heating means for the fluids in said conduit, a control valve governing the supply of heat to said heating means, and thermally sensitive mechanism associated with the fluids in said conduit for opening and closing said valve, said mechanism being associated with said conduit in such a manner as to also be responsive to the fluid pressure in said conduit to increase the range of the thermostatically responsive mechanism in accordance with the pressure decrease in the fluid.

6. An intake manifold heating system for internal combustion engines, comprising a heating jacket enveloping part of said manifold, a con trol valve governing the supply of heat to said heating jacket, an electrical circuit including a solenoid adapted when energized to operate said control valve, a thermostatically controlled switch in said circuit adapted to energize said solenoid upon an increase in temperature, and suction responsive means for increasing the closing temperature of said thermostatically controlled switch upon an increase in suction.

EDWARD E. DEAN;

OTTO? CARTER BERRY.

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