US3385275A - Ignition distributor advance control mechanism for a reciprocating engine - Google Patents

Description

May 28, 1968 D. M. BURNIA ETAL 3,385,275

IGNITION DISTRIBUTOR ADVANCE CONTROL MECHANISM FOR A RECIPROCATING ENGINE 2 Sheets-Sheet 1 Filed Oct. ll, 1967 A TTORNEVS D. M. BURNIA ETAL 3,385,275

May 28, 1968 IGNITION DISTRIBUTOR ADVANCE CONTROL MECHANISM FOR A RECIPROCATING ENGINE Filed Oct. 11, 1967 2 Sheets-Sheet 2 W/d 1/4/14 M. 1 /07 6 fl/SO/V a fM A TTORNEVS United States Patent O 3,385,275 IGNITION DISTRIBUTOR ADVANCE CON- TROL MECHANISM F OR A REOIPROCNL ING ENGENE Donald M. Burnia, Pontiac, and William M. Hutchison, Allen Park, Mich., assignors to Ford Motor Company, Dearborn, Mich, a corporation of Delaware Filed Oct. 11, 1967, Ser. No. 674,476 Claims. (Cl. 123-117) This mechanism is used with a dual diaphragm distributor to advance the ignition timing when the engine is decelerating and also advance the timing when engine temperature exceeds a predetermined maximum while the engine is idling. A housing is divided into lower and upper chambers by a plate carrying a thermally responsive valve. A pressure responsive valve extends through the plate. The bottom of the housing fits into an opening in the intake manifold so intake manifold vacuum is applied to the lower chamber. Hoses connect the upper chamber to the carburetor throttle bore and to the advance diaphragm of the distributor and another hose connects the lower chamber to the retarding diaphragm of the distributor. During normal operation, vacuum in the throttle bore passes through the upper chamber to position the advancing diaphragm. When the engine is decelerating, high manifold vacuum opens the pressure responsive valve to transmit manifold vacuum into the upper chamber, thereby advancing the ignition timing. When the engine is idling at normal temperature, a

manifold vacuum in the lower chamber acts on the retarding diaphragm to retard ignition timing for emission control. If the engine temperature exceeds a predetermined maximum, the thermally responsive valve opens to admit manifold vacuum to the upper chamber and thereby advance the ignition timing.

SUMMARY OF THE INVENTION erational phases. Additionally, engine idling with retarded timing increases engine operating temperature since the engine is running less efiiciently, so it is desirable to eliminate the spark retardation when extended idling raises engine temperature to the point where damage to engine components is probable.

In the past, a combination of at least two devices was used to achieve these features. Multiple devices were considered necessary because it was believed essential to locate the device for advancing ignition timing at idle in the engine cooling system or on the engine head, while the device for advancing the spark during 'decleration had to be subjected to intake manifold vacuum. In addition to the high material costs resulting from the use of multiple devices, installation procedures were lengthy and complicated and did not lend themselves to mass production techniques.

The distributor control mechanism provided by this invention is contained in a single housing attached to the engine intake manifold and greatly reduces material and assembly costs. In a reciprocating internal combustion engine having a metering device with an induction passage containing a throttle blade for supplying air to an ice intake manifold of the engine and having an ignition distributor for distributing ignition sparks to the engine, the distributor control mechanism comprises a housing divided into first and second chambers by a partition. The first chamber is connected to the interior of the intake manifold, while the second is connected to the induct on passage anterior of the throttle blade and to the spark advancing means for the distributor. A pressure responsive valve is located within the housing for connecting the second chamber to the intake manifold interior wh n manifold vacuum exceeds a predetermined maximum. In addition, a thermally responsive valve is located within the housing for connecting the first and second chambers when its temperature exceeds a predetermined maximum.

During acceleration, road load operation, and idling at normal temperatures, vacuum from the induction passage anterior of the throttle blade passes through the second chamber to position the spark advancing means on the distributor. Both of the valves in the control mechanism remain closed during the above operational phases. When the engine is decelerating, the high manifold vacuum opens the pressure responsive valve, which admits the manifold vacuum to the second chamber and thereby advances the timing. When the engine is idling, the temperature of the intake manifold becomes representative of the engine temperature. Thus, when the engine temperature rises, the temperature of a thermal element controlling the thermally responsive valve rises correspondingly and opens the thermally responsive valve when a predetermined temperature is reached.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is an exploded view of the control mechanism showing the structural relationship of the housing, the partition and the pressure responsive and temperature responsive valves. Portions of the components are broken away to show internal structure. FIGURE 2 is a schematic diagram showing the control mechanism of this invention with its connections to the carburetor, a dual diaphragm distributor and the engine intake manifold.

DETAILED DESCRIPTION Referring to FIGURE 1, the control mechanism of this invention is made up of a lower housing 10 and an upper housing 12 with a flat plate 14 serving as the partition dividing the interior of the assembled housing into a lower chamber 16 and an upper chamber 18. Lower housing 10 has a projection 20 formed on the bottom surface of two tubes 22 and 23 connected to a side. A lip 24 and a shoulder 25 surround the upper edge of the lower housing.

The valve body for the pressure responsive valve is a cylindrical member indicated by numeral 26. Valve body 26 has its exterior flared at the bottom as represented by numeral 28 to fit into the interior of projection 29. A shoulder 30 is formed near the top exterior of body 26 and external screw threads 32 are formed on the portion of body 26 above shoulder 30.

A large bore 34 extends into the interior of body 26 from the flared end and tapers into a smaller bore 36 at an interior shoulder 38. Positioned loosely in bore 34 is a valve member 40. A compressive spring 42 urges valve member 40 onto the seat formed by shoulder 38. Spring 42 is held in place by a jet 44 threaded into the lower end of bore 34. The wall of body 26 contains a hole 46 communicating with bore 34 above jet 44.

Plate 14 has a large hole 50 near the center thereof and a small hole 52 near one edge. A member 54 having a collar 56 formed around its upper end fits loosely in hole 52. A rubber O-ring 58 surrounds member 52 and 3 seats against the lower surface of collar 56. Below plate 14, member 54 is fastened to a bimetal strip 60 that is anch red to plate 14. Member 54, strip 60, and associated parts make up the temperature responsive valve.

Upper housing 12 has a flange 61 surrounding its lower edge and a hole 62 in its upper surface. Hole 62 is aligned with hole 50 in plate 14 and projection in lower housing 10. A pair of tubes 64 and 66 are fastened to one side of upper housing 12.

An internally threaded cap member 68 having a hexagon head 70 and an enlarged integral washer 72 is also used in the control mechanism. A hole '74 is formed in the wall of member 68 and an O ring seal 75 is adapted to lit the cylindrical portion of member 68.

The control mechanism is assembled in the following manner. First the flanged end 28 of valve body 26, which contains its internal components, is located in projection 20 so a hole in the bottom of projection 20 communicates with the hole in jet 44. A seal 48 is positioned on shoulder and plate 14 is positioned on seal 48 with the external screw threads 32. projecting through hole 50. Plate 14 rests on shoulder and an O ring (not shown) can be located between plate 14 and shoulder 30 if necessary for sealing purposes.

Upper housing 12 fits on plate 14, usually with another seal (not shown) similar to seal 48 interposed between flange 61 and plate 14. Lip 24 assists in properly locating plate 1 upper housing 12, seal 48 and its corresponding seal. Valve body 26 terminates Within chamber 18 below hole 62.

O ring 75 is slipped onto the cylindrical portion of cap member 68 and member 68 is inserted through hole 62 and threaded onto threads 32 until it seats on plate 14. Hole 74 is located so it is above the top of threads 32 and bore 36 communicates with chamber 18 through hole 74.

Referring now to FTGURE 2, numeral 76 designates a carburetor serving in the embodiment as the metering device, numeral 78 designates a portion of the intake manifold, and numeral 80 designates a portion of a dual diaphragm distributor for an internal combustion engine. Carburetor 76 has an induction passage 82 containing a conventional signal generating venturi section 84 and a throttle blade 86. Below throttle blade 86, induction passage 82 communicates with passage 88 in intake manifold 78.

The main housing 90 of the dual diaphragm distributor 80 contains the distributor advance plate 92 plus the distributor cam and other conventional distributor components (not shown). Rotation of the distributor cam is counterclockwise. Connected to the exterior of housing 90 is the vacuum advance motor housing 94. A diaphragm 96 forms an outer vacuum chamber 98 in housing 94 and a second annular shaped diaphragm 100 forms a second chamber 102 in housing 94. An arm 104 connects diaphragm 96 with the advance plate 92 in the distributor. A compressive spring 106 bearing on diaphragm 96 is mounted in chamber 98 and acts through diaphragm 96 and arm 104 to urge advance plate 92 toward a counterclockwise or retarded position.

Similarly, a spring 103 mounted in chamber 102 acts on diaphragm 100 to urge diaphragm 100 in the opposite direction. Diaphragm 100 is fastened to a position plate 110 that seats on a portion of housing 94 represented by numeral 112 when spring 103 is extended to its maximum position and seats on the portion represented by numeral 113 when a vacuum in chamber 102 draws the position plate to the left. The inner portion of plate 110 is adjacent a cup-shaped stop member 114 fastened to diaphragm 96.

Projection 29 of the control mechanism of this invention fits into intake manifold 78. A hose 116 connects a port 118 located just anterior of throttle blade 86 with tube 64 on upper housing 12. Another hose 120 connects tube 66 with chamber 98 in housing 94 and another hose 122 connects tube 23 with chamber 102 of housing 94.

4 In the FIGURE 2 embodiment, tube 22 is capped or plugged by any conventional means.

OPERATION While the engine is operating at road load or is accelerating, the vacuum signal appearing at port 118 is transmitted through hose 116, upper chamber 18, and hose 120 to chamber 98 where the signal positions diaphragm 96. Upper chamber 18 then is isolated from lower chamber 16, which is accomplished by selecting spring 42 so valve 40 remains seated under the relatively low manifold vacuum signals involved and selecting bimetal 68 so 0 ring 58 is held in contact with plate 14 at the temperatures involved. Manifold vacuum exists in lower chamber 16 and is transmitted to chamber 102 by hose 122, but the portion 112 of housing 94 prevents interference with the position of diaphragm 96 by the position of diaphragm 100.

When the engine is idling at temperatures up to normal, the vacuum at port 118 is substantially Zero and consequently the vacuum in chamber 98 also is substantially zero. Spring 106 moves diaphragm 96 to the left until stop member 114 contacts plate 110. The manifold vacuum at idle is relatively high (i.e., 15-18 inches of mercury) and a vacuum signal is transmitted through jet 44 and hole 46 into lower chamber 16. Hose 122 transmits the signal to chamber 102 where it overcomes the force of spring 108 and moves diaphragm to the left against portion 113 of housing 94. This permits spring 106 to move diaphragm 96 further to the left than pictured, thereby turning plate 92 counterclockwise and retarding the ignition.

The air flow over the engine at engine idle is reduced sufficiently so the heat transfer through the metal walls of the manifold renders the temperature of the control mechanism representative of engine temperature. If engine temperature rises, the temperature of bimetal strip 60 also rises and eventually strip 60 moves cylindrical member 54 upward, thereby moving 0 ring 58 out of contact with plate 14. A vacuum signal representative of the manifold vacuum existing in chamber 16 then is transmitted into chamber 18 and via hose to chamber 98. In chamber 98 the vacuum signal draws diaphragm 96 to the right, thereby advancing the ignition timing.

During decelerations, manifold vacuum rises above the values of manifold vacuum at engine idle (e.g., 23-25 inches of mercury). The higher manifold vacuum is applied through jet 44 to valve 40 and pulls valve 40 off shoulder 38. A vacuum signal then passes through bore 36 and hole 74 into upper chamber 18 and via hose 120 to chamber 98. In chamber 98, the vacuum draws diaphragm 96 to the right and thereby advances the ignition timing.

The sizes of the orifice in jet 44, hole 46, and hole 74 can be selected so vacuum signals less than but representative of manifold vacuum appear in lower chamber 16 and upper chamber 18. Hole 46, hole 74, valve 40 and hole 52 and valve member 54 can be selected so the vacuum signal appearing in chamber 18 during deceleration differs from the signal during hot idling.

Usually the signal in the upper chamber is about four to five inches of mercury when either of the pressure or temperature responsive valves are open. Note, however, that full manifold vacuum can be supplied to upper chamber 18 during deceleration while modulated vacuum is supplied during hot idling. A restriction can be insorted in tube 64, hose 116 or port 118 to prevent the vacuum signals appearing in upper chamber 18 when either the pressure or temperature responsive valve is open from being transmitted back to induction passage 82. In a preferred arrangement, hole 46 modulates the vacuum signal in chamber 16 to control the increase in engine idling speed when the temperature responsive valve opens, because full manifold vacuum can increase idling speed by several hundred r.p.m.s. Tapering member 54 produces the same control with the added feature of proportioning the speed increase to the temperature.

The dual diaphragm distributor used in the illustrated embodiment provides extra retardation of the ignition timing at idle. Of course, the control mechanism of this invention can be used with a conventional single diaphragm distributor lacking this feature. If desired, port 118 can be located in the carburetor venturi 84 or the signal for port 118 can be taken from a passage commuuicating with the venturi and the illustrated location just anterior of the throttle blade, with appropriate metering jets.

Since cap member 68 seats on plate 14 which in turn seats on shoulder 30, member 68' combines with body 26 to form a rigid structure extending vertically through the control mechanism so a force suflicient to press projection 20 into the opening in the intake manifold can be applied to the top of member 62. This arrangement greatly simplifies assembly of the control mechanism into the engine. If desired, hole 50 can be enlarged so member 68 seats directly on shoulder 30. Tube 22 can be used as a hose connection for routing manifold vacuum to other vehicle components.

Thus, this invention provides a unitary control mechanism for advancing ignition timing during engine deceleration and hot idling. The control mechanism is relatively inexpensive to build and assemble into vehicles, does not interfere with ignition timing during other operating phases, and permits varying the amount of advance during deceleration from the amount of advance during hot idling.

We claim:

1. In a reciprocating internal combustion engine having a metering device with an induction passa e containing a throttle blade for supplying air to an intake manifold of said engine and having an ignition distributor for distributing ignition producing energy to said engine, a distributor control mechanism comprising:

a housing attached by heat conducting means to the intake manifold,

a partition dividing said housing into first and second chambers with the first chamber connected to the interior of the intake manifold .and the second chamber connected to the induction passage anterior of the throttle blade,

passage means connecting said second chamber to an ignition timing means for the distributor, and

thermally responsive valve means located within said housing for connecting said first chamber to said second chamber, said thermally responsive valve means connecting said first and second chambers when engine temperature exceeds a predetermined maximum, said thermally responsive valve means being responsive to the temperature of the intake manifold.

2. The engine of claim 1 in which the thermally responsive valve means is located in the partition and comprising ressure responsive valve means located within said housing for connecting said second chamber to the intake manifold interior, said pressure responsive valve means making such connection when manifold vacuum exceeds a predetermined maximum.

3. The engine of claim 2 in which the control mechanism comprises a cylindrical member having an axial passage therein, said cylindrical member being positioned in said housing and extending through said partition with the bottom of said passage communicating with the intake manifold and the top communicating with the second chamber, said cylindrical member having an opening in its wall to connect the first chamber to the intake manifold via the lower part of said axial passage, said pressure responsive valve means being located in said passage above said opening.

4. The engine of claim 3 in which the housing of said control mechanism is pressed into a hole in the engine intake manifold.

5. The engine of claim 4 in which the control mechanism comprises a cap member threadably engaging said cylindrical member, said cap member and said cylindrical member having sufiicient structural rigidity to transmit a force capable of pressing the housing of the control mechanism into the engine intake manifold.

6. The engine of claim 5 in which the ignition distributor is a dual diaphragm distributor, the second chamber of the control mechanism is connected to the chamber in the distributor positioning the advance diaphragm, and the first chamber is connected to the chamber in the distributor positioning the retard diaphragm.

7. The engine of claim 2 in which the control mechanism comprises a cylindrical member having an axial passage therein, said cylindrical member being positioned in said housing and extending through said partition with the bottom of said passage communicating with the intake manifold and the top communicating with the second chamber, said cylindrical member having an opening in its wall to connect the first chamber to the intake manifold via the lower part of said axial passage, said pressure responsive valve means being located in said passage above said opening.

8. The engine of claim 7 in which the control mechanism comprises a cap member threadably engaging said cylindrical member, said cap member and said cylindrical member having sufiicient structural rigidity to transmit a force capable of pressing the housing of the control mechanism into the engine intake manifold.

9. The engine of claim 1 in which the housing of said control mechanism is pressed into a hole in the engine intake manifold.

10. The engine of claim 1 in which the ignition distributor is a dual diaphragm distributor, the second chamber of the control mechanism is connected to the chamber in the distributor positioning the advance diaphragm, and the first chamber is connected to the chamber in the distributor positioning the retard diaphragm.

References Cited UNITED STATES PATENTS 2,702,028 2/1955 Gintling 123-117 2,809,619 10/1957 Norris 123-117 2,809,620 10/1957 Boylan 123-117 2,876,754 3/1959 Obermaier 123-117 3,057,938 10/1962 Perry 123-117 X 3,252,451 5/1966 Sarto 123-117 3,301,242 1/ 1967 Candelise 123-117 3,081,793 3/1963 Flatt 123-117 3,162,184 12/1964 Walker 123-117 RALPH D. BLAKESLEE, Primary Examiner.

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