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Publication numberUS3827413 A
Publication typeGrant
Publication dateAug 6, 1974
Filing dateMar 2, 1973
Priority dateMar 2, 1973
Publication numberUS 3827413 A, US 3827413A, US-A-3827413, US3827413 A, US3827413A
InventorsMeacham G
Original AssigneeEaton Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Timing control system
US 3827413 A
Abstract
A mechanism for maintaining a predetermined angular phase relation between a distributing device and a crankshaft in an internal combustion engine of the type employing an apparatus for varying the timed angular phase relation between the engine crankshaft and camshaft. This mechanism, in one disclosed embodiment, comprises a device drivingly interconnecting the camshaft and the crankshaft and operative to vary the angular phase relationship therebetween, a distributor drive gear journaled on the camshaft, and a spider driving the distributor drive gear in a constant angular phase relationship with the crankshaft irrespective of varying phase relationships between the camshaft and the crankhaft. Several other mechanisms are also disclosed.
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Description  (OCR text may contain errors)

Unite States Eatent 1191 Meacham 1 1 TIMING CONTROL SYSTEM [75] inventor: George B. K. Meacham,

Birmingham, Mich. [73] Assignee: Eaton Corporation, Cleveland, Ohio [22] Filed: Mar. 2, 1973 [21] Appl. No.: 337,512

[52] US. Cl 123/99, 64/25, 123/90.15, 123/117, 123/148 R, 123/195 A, 123/90.18 [51] Int. Cl. F0201 37/06 [58] Field of Search... 64/25, 24; l23/90.15, 90.18, l23/99,117,195 A, 148 R, 150 R [56] References Cited UNITED STATES PATENTS 2,121,560 6/1938 Duncan 123/90.15 2,804,061 8/1957 Gamble 123/90.l8 3,301,010 l/1967 Vcrnick 4 64/25 3,685,499 8/1972 Mcacham ct 111.. 123/90. 15 3,721,220 3/1973 Garcca 123/9().15 3,732,745 5/1973 Jackson l23/90.15

3,87,413 Aug. 6, 1974 ABSTRACT A mechanism for maintaining a predetermined angular phase relation between a distributing device and a crankshaft in an internal combustion engine of the type employing an apparatus for varying the timed angular phase relation between the engine crankshaft and camshaft. This mechanism, in one disclosed embodiment, comprises a device drivingly interconnecting the camshaft and the crankshaft and operative to vary the angular phase relationship therebetween, a distributor drive gear journaled on the camshaft, and a spider driving the distributor drive gear in a constant angular phase relationship with the crankshaft irrespective of varying phase relationships between the camshaft and the crankhaft. Several other mechanisms are also disclosed.

31 Claims, 8 Drawing Figures f L J/ \j 1 1; Zia y R714 6 1111 4. f I W 4 $2? 1 e 7 t M I 1 i i l 2 P S i4 ,7! 2&5

TIMING CONTROL SYSTEM FIELD OF THE INVENTION BACKGROUND OF THE INVENTION There is presently a great deal of concern about air pollution, much of which is said to be contributed by exhaust gases from internal combustion piston engines. Great effort has been expended in search of methods for controlling the level of noxious emissions from such engines. One concept found to be effective for such control, and at the same time compatible with the contemporary design of such engines, is explained in detail in U.S. Pat. No. 3,714,932, Emissions Control System and U.S. Pat. No. 3,626,720, Emission Control Device.

While the concept disclosed in the mentioned applications is effective in substantially reducing noxious exhaust gas emissions by selectively varying the angular phase relation of the camshaft with respect to the crankshaft, it creates a problem with ignition timing in engines having camshaft mounted distributor drive gears. Specifically, the camshaft phase change creates an ignition timing change of a magnitude and direction equal to the camshaft phase change. This timing change produces undesirous combustion characteristics and less than optimum control of noxious exhaust gas emissions.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved timing control system for an internal combustion engine.

A more specific object is to provide, in an internal combustion engine of the type including a crankshaft, a camshaft, and a camshaft driven distributing device, a timing control system which optimizes combustion characteristics and control of noxious exhaust gas emissions.

These objects are accomplished according to the present invention by the provision of a timing control system in which the angular phase relationship between the crankshaft and the camshaft is selectively varied in response to a sensed engine operating condition, whereby to provide combustion characteristics which minimize noxious emissions, and in which further means are provided to maintain the predetermined angular phase relationship between the crankshaft and the camshaft driven distributor device irrespective of the variations in the angular phase relationship between the crankshaft and the camshaft, whereby to further improve the emission characteristics by maintaining optimum distributor timing.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a fragmentary elevational view, partially in section, illustrating one embodiment of the invention timing control system employing a distributor drive gear joumaled on a camshaft;

FIG. 2 is a sectional view, taken along line 2-2v of FIG. 1;

FIG. 3 is a fragmentary elevational view, partially in section, illustrating a second embodiment of the invention timing control system employing mechanical linkage;

FIG. 4 is a sectional view taken along line 44 of FIG. 3;

FIG. 5 is a fragmentary view, partially in section, illustrating a third embodiment of the invention timing control system employing fluid displacement cylinders;

FIG. 6 is a fragmentary view, partially in section, illustrating a fourth embodiment of the invention timing control system employing vacuum operated motors;

FIG. 7 is an elevational view in reduced size illustrating a fifth embodiment of the invention timing control system which also employs vacuum operated motors; and

FIG. 8 is a partially sectioned view, taken along the line 88 of FIG. 7.

DETAILED DESCRIPTION OF FIGS. 1, 2 EMBODIMENT FIG. 1 illustrates a fragment of an engine block 10 having a front wall portion 10a, a crankshaft 12, a camshaft 14, a drive gear assembly 16, and a camshaft angular phase change mechanism 18 drivingly interconnecting camshaft 14 and drive gear assembly 16 to the crankshaft.

Crankshaft 12 is schematically shown joumaled in an antifriction bearing 19 supported within an aperture 20 in wall 10a. A timing pinion 22 is secured to the forward end of crankshaft 12. A ring-shaped camshaft timing gear 24 is drivingly connected to pinion 22 via a timing chain 26.

Drive gear assembly 16 is substantially sleeve-shaped and includes an ignition distributor drive gear 16a having a plurality of helical gear teeth 16b, an antifriction bearing surface 160, a hub portion 16d, a smooth cylindrical bore 162, and an annular recess 16f at the leftward end of bore 16e. Bearing surface 16c is joumaled within a sleeve bearing 28 supported in an aperture 30 in wall 10a. Gear teeth 16b are adapted to drive an ignition distributor pinion (not shown).

Camshaft 14 is rotatably supported within bore Me of drive gear assembly 16 via a journal portion 14a formed on the forward end of the camshaft. An annular rib portion 14b formed on the leftward end of journal portion 14a mates with recess 16f and provides a leftward stop for seating drive gear 16 in the axial direction. The forwardmost part of journal portion 14 extends through bore Me and defines a hub portion which is adapted to support phase change mechanism 18.

Camshaft phase change mechanism 18 when operated functions to change the angular phase relationship between crankshaft 12 and camshaft 14. A more detailed description of mechanism 18 may be found in U.S. Pat. No. 3,626,720. Phase change mechanism 18 includes a piston 32 and a driven member 34, the latter being nonrotatably secured to hub portion 140 of the camshaft.

Driven member 34 includes a disk portion 34a, a hollow rearwardly extending hub portion 34b, and a hollow forwardly extending hub portion 34c. I-Iub portion 34b is adapted to fit snugly over hub portion 140, and is secured thereto against axial movement by a bolt 36 and against rotational movement by dowels 38.

Piston 32 includes a disk portion 32a, a, hollow hub portion 32b, and an annular rim portion 32c. Hub portion 32b is rotationally and slideably received within the hollow of hub portion 340 and sealed therebetween by an O-ring seal 35. Disk portion 34a and hub portion 340 combine with disk portion 32a and rim portion 320 to define an annular chamber 40 having a helical ball spline device 42 disposed therein.

The helical ball spline device 42 includes an annular outer race 44 securely fixed to disk 34a and an annular inner race 46 circumscribed by outer race 44 and securely fixed to disk 32a. An outer circumferential surface 44a of outer race 44 is rotationally and slideably received within a cylindrical bore defined by an inner surface 32d of annular rim 32c and sealed therebetween by an O-ring seal 47. The inner periphery of outer race 44 is provided with a plurality of straight circumferentially spaced slots 44b. Slots 44b extend substantially parallel to the axis of camshaft 14 and are disposed adjacent similar circumferentially spaced and angularly extending slots 46a formed in the outer periphery of inner race 46. Each corresponding pair of slots 44b, 46a is provided with a spherical ball 48 therein for drivingly interconnecting slots 44b and 46a, and hence, providing relative rotation between piston 32 and drive member 34 in response to axial movement of piston 32 relative to driven member 34.

Piston 32 is drivingly engaged to timing gear 24 by a plurality of straight splines 32e formed on the outer periphery of rim portion 32c. Splines 32e engage similar straight splines 24a formed on a portion of the inner periphery of camshaft timing gear 24. The other inner peripheral portion of timing gear 24 is rotationally received about the outer peripheral edge of disk portion 34a and is held axially secure thereto by a snap ring 50 and the butt ends of splines 24a.

Drive gear assembly 16 is drivingly connected to timing gear 24 via an oval shaped spider 52, as shown in FlGs. l and 2. Spider 52 is formed from sheet metal and is freely received within a gap defined by the axially facing ends of hubs 16d and 34b. A centrally located aperture 52a in spider 52 freely receives hub portion 140 of camshaft 14. Spider 52 is secured to timing gear 24 by screws 56 and to hub 16a of drive gear 16 by dowel pins 58..

A servo valve assembly 60, disposed within hollow hub portion 32b, provides means for admitting pressurized engine oil to chamber 40 or to drain oil therefrom for the purpose of axially shifting piston 32. The hollow of hub portion 32b is provided with stepped bores 32f and 32g. An extension of bolt 36 defines a shaft 36a which is slideably and rotatably received in bore 32f; sealing th'erebetween is provided by an O-ring seal 62. Bore 32g is provided with an annular groove 64 which is supplied with engine oil from a passage 66 in wall portion a via a plurality of intermediate passages. Specifically,- passage 66 extends through bearing 28 and terminates in an annular groove 68 formed in the periphery of bearing surface 16c of drive gear assembly 16. Groove 68 communicates with a plurality of radially extending passages 70 which terminate in an annular groove 72 formed in the peripheral surface of journal portion 14a of camshaft 14. Groove 72 communicates through a radially extending passage 74 with an axially-extending passage 76, which in turn communicates with groove 64 via passages 78, 80 in driven member 34 and hub portion 32b respectively. Bore 32g is provided with a second annular groove 82 which is axially spaced from groove 64 by an annular land 84, Annular groove 82 communicates with chamber 40 via a passage 86.

A shiftable spool valve 88 is provided to control oil flow into or from chamber 40. Spool 88 is slideably positioned within bore 32g in surrounding relation to shaft 36a and is provided with a pair of annular grooves 88a, 88b which are separated by a land 880 in slideable sealing engagement with bore 323. A wave spring 90 lightly biases spool 88 to the right and a snap ring 92 limits rightward movement of spool 88 within bore 32g. A drain passage 94 communicates groove 88b with an appropriate sump for return of oil to the engine.

Spool valve 88 is maintained in a desired position by a control arm 96. Control arm 96 is a rigid structure which includes a forked end portion 96a positioned adjacent the rightward end of the spool valve, a handle 96b, and a pivot shaft 960. Pivot shaft 96c is rotatably secured in a block 98 which is secured to a wall portion 100 of a cover assembly (not shown) enclosing the mechanisms extending beyond the front wall 10a of engine 10.

The cover assembly is secured to wall 100. Handle 96b extends through wall portion 100 of the cover assembly and is controlled by an appropriate control system which responds to certain engine operation conditions which produce high concentrations of noxious exhaust emissions. One such servo control system using engine vacuum is disclosed in the aforementioned US. Pat. No. 3,626,720. Testinghas shown the such operating conditions are discernable by the measure of carburetor spark port vacuum, engine speed, or engine torque.

OPERATION OF FIGS. 1, 2 EMBODIMENT During one mode of engine operation camshaft phase change mechanism 18 is in the position shown in FIG. 1, Le, piston 32 is fully retracted and chamber 40 is a minimum in volume. In this mode of operation control arm 86 is fully rotated clockwise about pivot shaft 96c and land 88c is blocking oil communication between grooves 64, 84 via groove 88a. When an engine operating condition arises which makes it advantageous to vary the angular phase relationship between the camshaft and the crankshaft, control arm 96 is rotated counterclockwise about pivot shaft 960; this allows spool valve 88 to shift rightward under the force of wave spring 90, thereby communicating grooves 64, 88 via groove 88a and allowing pressurized engine oil to flow into chamber 40. Piston 32 will thus shift rightwardly under the oil pressure to the position shown by broken line 102 or any position intermediate as determined by the amount of servo valve movement allowed by control arm 96. The rightward movement of piston 32 causes piston 32 to rotate relative to driven member 34 due to the aforedescribed spline arrangement in helical spline device 42 and, hence, the angular phase relationship between crankshaft 12 and camshaft 14 is changed.

However, as may be seen, this angular phase change between piston 32 and driven member 34 is entirely independent of the phase relationship between timing gear 24 and drive gear 16 since spider 52 provides the driving connection between timing gear 24 and drive gear 16. Therefore, drive gear 16 remains in a constant phase relationship with crankshaft l2 irrespective of the phase relationship betweencrankshaft 12 and camshaft 14.

DETAILED DESCRIPTION OF FIGS. 3, 4 EMBODIMENT PIGs. 3 and 4 schematically illustrate another embodiment of the invention. In this embodiment like components have the same numerals used to designate corresponding parts in the previous embodiment but a suffix A- is added thereto. Succeeding embodiments will follow this procedure using consecutive upper case suffixes. In this embodiment spider 52 is omitted and the camshaft drive gear is fixed to rotate with the camshaft. Other than this the angular phase change mechanism is identical in structure and operation to the mechanism of FIGS. 1 and 2. In this embodiment a mechanical linkage system 104 is provided to compensate for distributor timing changes that are transmitted to a distributor 106 as a result of camshaft angular phase changes relative to the crankshaft, and a distributor drive gear 108a is carried by and driven by a camshaft 108.

The distributor 106 includes a head assembly 110, a mounting stand 112. The distributor 106 departs from standard distributors in that the head assembly 110 is rotatable relative to the mounting stand 112. A lower portion 112a of the mounting stand 112 is received by an aperture 114a in a wall portion 114 of an engine block. A radially extending flange 112b formed on mounting stand 112 limits the depth of reception of the lower portion 112a into the aperture 114a and provides means for securely fixing the position of the stand relative to the wall portion 112, as shown, by bolt 116 and clip 118.

The distributor head 110 and stand 112 have coaxial openings 120 and 122, respectively, in which rotatably receive a distributor drive shaft 124. A pinion 124a secured to the lower end of shaft 124 meshes with camshaft drive gear 108a. The upper end of the shaft 124 extends through a centrally positioned clearance hole 126a in a breaker point mounting plate 126. A breaker point cam 124b formed on upper end of shaft 124, or otherwise secured thereto, functions to open and close a set of breaker points 128 mounted on plate 126 in a well known manner.

An upper axial end face 112a of the stand 112 serves as a bearing surface for a lower face 110a of the head 110. A spring 130 is disposed between two outwardly extending arms 11% and 112d which are integrally formed with head 110 and stand 112, respectively, as best shown in FIG. 4. The spring 130 biases head assembly 110 downward and counterclockwise as viewed in FlGs 3 and 4.

The mechanical linkage system 104 responds to axial movement of piston 32A of phase change mechanism 18A and rotates head assembly 110 to correct for angular phase changes transmitted to breaker point cam 124b when the phase change mechanism shifts the angular phase relationship between the crankshaft and the camshaft. Linkage system 104 includes a pivot shaft 132, a crank arm 134, a pin 136, and a radially outwardly extending arm 110C formed integrally with head assembly 110. Pivot shaft 132 includes a vertical rod portion 132a journaled in a pair of blocks 138 and a follower portion 132b which rides on the face of piston 32A. Blocks 138 are supported on an appropriate bracket 140 secured to the engine in a conventional manner. The top end of rod 132a is securely fixed to one end of crank arm 134. The other end of crank arm 134 is securely fixed to the lower end of pin 136. An

elongate slot 110d formed in the free end of arm 110c 5 loosely receives a necked down portion at the top end of pin 136.

The above embodiment has been described and shown schematically for ease of understanding but it should be realized that in actual practice each engine model and installation will require slight design changes in the linkage configuration due to peculiarities that are inherent in different engine models and installations. For example, the arms 134 and 1100 may be separated by a substantial distance in which case a push-pull rod or a flex cable may be used in lieu of pin 136 to transmit the timing compensation signal from the camshaft angular phase change mechanism 18A to the distributor head assembly 110. Further, head assembly 110 and mounting stand 112 may be unitary in construction (as are standard distributors) with rotation occurring in the aperture 114a.

OPERATION OF FIGS. 3, 4 EMBODIMENT When the piston 32A moves axially to the left (FIG. 3), the distributor compensation mechanism will operate due to rotation of the follower 132b and thereby cause the crank arm 134 to rotate. Rotation of crank arm 134 is transmitted into rotatory movement of dis- 3 tributor head assembly 110 via pin 136, and arm 110C.

As may be seen, the amount of distributor head rotation depends on the amount of axial movement of the piston 32A which is proportional to the amount of camshaft phase change. In tests using camshaft advance to reduce exhaust emission, it has been found that a oneto-one compensation (i.e. for each degree of camshaft advance, the compensation system retards the distributor one degree to maintain ignition timing in phase with the crankshaft) results in the best performance for most engines and at the same time produces the best control of emissions. However, on some types of engines compensation of less than or more than one-toone produces the best results. Of course the ratio of compensation is controllable by varying the length of follower 132b and/or crank arms 134 and 1100.

DETAILED DESCRIPTION OF FIG. 5 EMBODIMENT FIG. 5 is a third embodiment which schematically illustrates a variation of the compensation means shown in FIGs. 3 and 4. The angular phase change mechanism 18B and the distributor 1068 are substantially the same as disclosed in FIGs. 3 and 4. In this embodiment a closed hydraulic system is used in lieu of the mechanical linkage system of FIGS. 3 and 4.

Closed hydraulic system 150 includes two cylinder assemblies 152, 154 which define interconnected chambers 156, 158 of variable volume. Chamber 156 is defined by a cylinder wall 160, an end wall 162, and a piston 164. Cylinder assembly 152 is secured to the engine by a bracket in a conventional manner. Piston 164 is connected to a follower 166 via a piston rod 168 which passes freely through an opening in an end wall 170 at the other end of cylinder wall 160. Chamber 158 is defined by a cylinder wall 172, an end wall 174, and a piston 176. Cylinder assembly 154 is secured to stand 1128 of distributor 1068 via a bracket 177 in a conventional manner. Piston 176 is pivotally connected to the free end of an arm 178 via a piston rod 180 which passes freely through an opening in an end wall 182 at the other end of cylinder wall 172. Arm 178 is a radially outwardly extending portion of head assembly 110B and is functionally equivalent to arm 1100 in FlGs. 3 and 4. A spring 184 interposed between piston176 and end wall 182 biases piston 176 to the left. Chambers 156, 158 are interconnected by a conduit 186.

OPERATION OF FIG. 5 EMBODIMENT When piston 32B is retracted the volume of chamber 158 will be at a minimum due to the action of spring 184 which biases piston 176 leftward. This leftward biasing of piston 176 forces the hydraulic fluid from chamber 158 to chamber 156 via conduit 186 and causes piston 164 to move rightwardly, thereby holding follower 166 into sliding contact with piston 328. When an engine operating condition arises that calls for a camshaft angular phase change the phase change mechanism 188 is operated and piston 32B moves axially to left, thereby moving piston 164 leftward and forcing fluid from chamber 152 into chamber 158; this causes piston 176 to move against the force of spring 184, thereby rotating head assembly 1108 via rod 180 and arm 178.

DETAILED DESCRIPTION OF FIG. 6 EMBODIMENT FIG. 6 is a fourth embodiment of the invention which schematically illustrates a vacuum operated compensation system 190. The angular phase change mechanism 18C and the distributor 106C are substantially the same as disclosed in FIGs. 3 and 4. Operation of the compensation means in FIGS. 3, 4 and 5 is responsive to axial movement of piston 32. In this embodiment the spark port vacuum signal described in connection with FIGs. 1 and 2 is used to provide both servo valve control and distributor compensation control.

Vacuum operated compensation system 190 includes two vacuum motors 192, 194 which are parallel connected to a spark port vacuum conduit 196 via conduits 198, 200, respectively. Vacuum motor 192 includes housing members 202 and 204, a spring 206, a flexible wall 208 and a control rod 210 which freely extends through an opening in housing member 204. Control rod 210 includes a fork shaped end portion 211 which is biased into sliding contact with servo valve 88C by spring 206. Conduit 198 communicates with a vacuum chamber 212 defined by housing member 202 and flexible wall 208. Vacuum motor 194 includes housing members 213 and 214, a spring 215, a flexible wall 216, and a control rod 217. Control rod 217 is pivotally connected to the free end of arm 178C, as described with uum signal is applied constantly to chambers 212 and 218.

OPERATION OF FIG. 6 EMBODIMENT Springs 206 and 215 when fully expanded in their respective chambers are preloaded to prevent movement of the flexible walls until the spark port vacuum reaches a predetermined amount which corresponds to an engine operating condition known to produce high concentration of noxious exhaust. When this predetermined amount of vacuum is exceeded flexible walls 208 and 216 and their respective control rods shift to the left by an amount proportional to the amount of vacuum in excess of the predetermined amount. Leftward movement of control rod 210 allows servo 88 (FIG. 1) to shift under the bias of wave spring 90, thereby admitting pressurized engine oil to chamber 40 and thus varying the angular phase relationship between the crankshaft and the camshaft. Since the vacuum is also applied to chamber 218, distributor head assembly 110C is rotated enough to compensate for the amount of change between the camshaft and the crankshaft.

DETAILED DESCRIPTION OF FIGS. 7, 8

EMBODIMENT In this embodiment, the servo valve of the camshaft angular phase change mechanism may be controlled by reference to the FIG. 5 embodiment. Conduit 200 coma vacuum motor such as shown in FIG. 6.

FIG. 7 illustrates a distributor installation comprising a distributor 220, a wall portion 222 of an engine (not shown), and a camshaft 224 with a camshaft driven distributor drive gear 226. The distributor drive gear 226 is fixed to rotate with the crankshaft and, therefore, imparts a timing change to the distributor, relative to the crankshaft, whenever the camshaft phase is changed relative to the crankshaft phase.

With reference to FIG. 8, the distributor 220 comprises a housing 228, a breaker plate 230, a breaker point assembly 232 mounted on plate 230, a breaker point cam 233 driven by distributor drive gear 226, a vacuum motor 234 for timing compensation due to a camshaft angular phase change, and a vacuum motor 236 for normal vacuum control of ignition timing as is well known in the art.

The vacuum motor 234 comprises housing members 238 and 240, a flexible wall 242 (which in combination with the member 238 forms a vacuum chamber 244), a spring 246, a conduit 248 for communicating a vacuum to the chamber 244, a bracket 250 for movably mounting the vacuum motor 234 to the distributor 220 via slots 252 and 254 which slide on screws 256 and 258, and a control arm 260 for rotating the breaker plate 230 in response to movement of the flexible wall 242.

The vacuum motor 236 comprises housing members 262 and 264, a flexible wall 266 (which in combination with the member 262 forms a vacuum chamber 268), a spring 270, a conduit 272 for communicating a vacuum to chamber 268, a bracket 274 for securing the motor 236 to the housing 228 in a fixed position, and a control arm 276 for linear movement in the bracket 250 in response to movement of the flexible wall 266.

Conduits 248 and 272 are parallel connected and in constant communication with the spark port vacuum chamber in the same manner conduits 198 and 200 are connected in FIG. 6.

OPERATION OF FIGS. 7, 8 EMBODIMENT The inner connection between the normal vacuum control motor 234 and the timing compensation motor 232 maintains ignition timing'in a predetermined relation with the crankshaft by superposition, i.e., the sum of the movement of control arms 260 and 274 determine the ignition timing for any particular operating condition.

When spark port vacuum is very low in chamber 268 spring 270 biases diaphragm 266 rightwardly against housing member 624 with a predetermined force; this position of diaphragm 266 corresponds to full retardation of the vacuum advance motor 236. When diaphragm 266 is against housing member 624, the right end of slots 252 and 254 of bracket 250 are biased against screws 256 and 258, respectively. In a like manner, when spark port vacuum is very low in chamber 244 spring 246 biases diaphragm 242 against housing member 240 with a predetermined force; in this position there is no timing compensation nor is there an angular phase change between the crankshaft and the camshaft since the phase change mechanism is also controlled by spark port vacuum. Low spark port vacuum occurs when the engine is idling, due to the relative positions of the throttle and the spark port, and during high engine load conditions.

As the vacuum in chamber 268 increases diaphragm 266 is pulled to the right against the force of spring 270, whereby control arm 276 pulls bracket 250 and vacuum motor 234' to the right relative to distributor 220. Since the biasing force of springs 246 and 270 is greater than the rotational resistance of the breaker plate rightward movement of motor 234 shifts control arm 260 rightward and rotates breaker plate 230 counterclockwise to advance the ignition timing.

As the vacuum in chamber 234 increases diaphragm 244 is pulled leftwardly against the biasing force of spring 246, thereby rotating breaker plate 230 clockwise to retard the timing an amount proportional to the ignition timing advance caused by the phase change mechanism.

The several embodiments of the invention has been disclosed for illustrative'purposes. The following claims are intended to cover the inventive portions of the disclosed embodiments and variations or modification within the spirit of the invention.

1 claim:

1. A timing control system for an internal combustion engine of the type including at least one cylinder, a piston slideably received in said cylinder, a camshaft, and

a crankshaft drivingly connected to said camshaft; said timing system comprising:

A. means for sensing engine operating conditions;

B. means responsive to sensed changes in operating conditions of said engine to selectively vary the angular phase relation of said camshaft and said crankshaft;

C. gear means carried by and coaxial to said camshaft;

D. a distributing device driven by said gear means for delivering a charge in a predetermined timed relation to said crankshaft; and

E. means operative to substantially maintain said predetermined timed relation between said distributing device and said crankshaft irrespective of variations in the angular phase relation between said camshaft and said crankshaft.

2. The timing control system of claim 1, wherein F. said gear means is journaled on said camshaft.

5 3. The timing control system of claim 2, wherein G. said responsive means including a timing gear driven by said camshaft; and

H. said operative means including a spider drivingly connecting said gear means to said timing gear.

4. The timing control system of claim 1, wherein F. said operative means is a linkage system controlled by said responsive means.

5. The timing control system of claim 4, wherein G. said responsive means includes a piston member movable in response to said sensed changes; and

H. said linkage system is controlled by movement of said piston.

6. The timing control system of claim 5, wherein I. axial movement of said piston member varies said angular phase relation between said camshaft and said crankshaft; and

J. said linkage system is responsive to axial movement of said piston.

7. The timing control system of claim I, wherein F. said responsive means is controlled by vacuum pressure from said engine.

8. The timing control system of claim 7, wherein G. said vacuum pressure is spark port vacuum pressure.

9. The timing control system of claim 1, wherein F. said gear means is fixed to rotate with said camshaft, whereby a variation in the angular phase relation between said camshaft and said crankshaft produced by said responsive means tends to change the timed relation between said distributing device and said crankshaft; and

G. said operative means includes means connected to said distributing device for imparting a timing compensation to said distributor counter to said timing change produced by said responsive means.

10. The timing control system of claim 9, wherein I-I. said responsive means includes a piston member movable in response to said sensed changes; and I. said connected means imparts said timing compensation in response to movement of said piston. 11. The timing control system of claim 10, wherein J. axial movement of said piston member varies said angular phase relation between said camshaft and said crankshaft.

12. The timing control system of claim 11, wherein K. said connected means includes a follower for sensing axial movement of said piston. 13. The timing control system of claim 12, wherein said connected means further includes L. a shaft rotated in response to movement of said follower; and M. a crank arm operative to impart said timing compensation to said distributor in response to rotation of said shaft. 7 14. The timing control system of claim 12, wherein said connected means further includes L. a closed hydraulic system having 1. a first cylinder and a first piston defining a first variable volume fluid chamber, said piston connected to said follower and operative to vary the volume of said first chamber, and 2. a second cylinder and a second piston defining a second variable volume fluid chamber in communication with said first chamber, said second piston connected to said distributing device and operative to impart said timing compensation to said distributor in response to variations in the volumes of said chambers. 15. The timing control system of claim 9, wherein H. said connected means includes motor means operative to impart said timing compensation to said distributing device in response to said sensing means sensing changes in said engine operating conditions. 16. The timing control system of claim 15, wherein I. said sensing means senses engine vacuum pressure;

and

J. said motor means is a timing compensation vacuum motor.

.17. The timing control system of claim 16, wherein K. said engine vacuum is carburetor spark port vacuum. 18. The timing control system of claim 17, wherein L. said distributing device is an ignition distributor contained in a housing; and

M. said vacuum motor imparts said timing compensation to said distributor by rotating said housing.

19. The timing control system of claim 16, wherein K. said distributing device is an ignition distributor having 1. a housing fixed to said engine, and 2. a movable breaker plate mounted in said housg; l L. a bracket slideably mounting said timing compensation vacuum motor on said housing; M. a second vacuum motor fixed to said housing and having 1. a movable wall responsive to said engine vacuum pressure, 2. a control arm secured to one end to said bracket;

N. said timing compensation vacuum motorhaving l. a movable wall responsive to said engine vacuum pressure,

2. a control arm secured atone end to said movable wall and at the other end to said movable breaker plate.

20. A mechanism for maintaining a predetermined angular phase relation between a distributing device and crankshaft in an internal combustion engine, said mechanism comprising:

A. a drive pinion driven by said crankshaft;

B. a timing gear driven by said pinion;

C. means driven by said timing gear for driving said camshaft in a timed angular phase relation to said crankshaft, said means selectively operable to vary-'- shaft independent of said means driven by said timing gear.

21. A mechanism as recited in claim 20, wherein F. said distributor drive gear means is a spider driven by said timing gear.

22. A mechanism as recited in claim 20, wherein F. said gear means includes an antifriction bearing journaling said camshaft in the housing of said internal combustion engine.

23. A timing control system for an internal combustion engine of the type including at least one cylinder, a piston slideably received in said cylinder, a camshaft, and a crankshaft drivingly connected to said camshaft, said timing system comprising:

A. means for sensing engine operating conditions;

B. means responsive to sensed changes in operating condition of said engine to selectively vary the angular phase relation of said camshaft and said crankshaft;

C. a distributing device driven by said camshaft for delivering a charge in a predetermined timed relation to said camshaft; and

D. means operative to substantially maintain said predetermined timed relation between said distributing device and said camshaft irrespective of variations in the angular phase relation between said camshaft and said crankshaft.

24. The timing control system of claim 23, wherein E. said responsive means includes a piston member movable in response to said sensed changes; and F. said operative means is responsive to movement of said piston. 25. The timing control system of claim 24, wherein G. said distributing device is an ignition distributor contained in a housing.

26. The timing control system of claim 25, wherein said operative means comprises:

H. a bracket mounted on said engine;

I. a shaft journaled on said bracket;

J. a follower having one end fixed to said shaft and the other end in sliding contact with said piston, whereby movement of said piston rotates said shaft;

K. a first crank arm fixed at one end to said shaft for pivotal movement in response to rotation of said shaft;

L. a second crank arm fixed atone end to said housing of said distributing device; and

M. a linkage connecting the free end of said first crank arm to the free end of said second crank arm for rotating said housing in response to said pivotal movement of said first crank arm.

27. A device asrecited in claim 25, in which said operative means comprises:

A. a crank arm fixed at one end to said distributor housing;

B. a first cylinder;

C. a piston in said first cylinder;

D. an end wall fixed to said first cylinder, said first cylinder, piston and end wall defining a first fluid chamber;

E. a control arm fixed at one end to said piston and at the other end pivotally connected to the free end of said crank arm;

F. a second cylinder;

G. a second piston in said second cylinder;

H. a second end wall fixed to said second cylinder, said second cylinder, second piston, and second end wall defining a second fluid chamber;

I. a follower adjacent to and in sliding contact with said movable piston;

J. a rod fixed at one end to said piston and at the other to said follower;

K. a conduit communicating said first fluid chamber with said second fluid chamber; and

L. resilient means in said first cylinder for urging said piston to a position minimizing the volume of said first fluid chamber and maximizing the volume of said second fluid chamber.

28. The timing control system of claim 23, wherein 29. The timing control system of claim 23, wherein E. said distributing device is an ignition distributor contained in a housing;

F. said operative means includes a vacuum motor having l. a housing,

2. a movable wall,

3. a vacuum chamber defined by said housing and movable wall,

4. a control arm secured to said movable wall at one end, and pivotally connected to said distributor housing at the other end, and

5. means communicating engine vacuum pressure to said chamber.

30. The timing control system of claim 29, wherein G. said engine vacuum pressure is carburetor spark port vacuum pressure.

31. An internal combustion engine comprising:

A. a crankshaft;

B. a camshaft;

C. driven means drivingly connecting said crankshaft to said camshaft, said driven means selectively operative to vary the angular phase relation between said camshaft and said crankshaft;

D. a gear means carried by and coaxial to said camshaft;

E. means defining at least one cylinder having a piston slideably received therein and drivingly connected to said crankshaft;

F. distributor means drivingly connected to said gear means in timed relation to said crankshaft and selectively operative to deliver a charge to said at least one cylinder in a timed relation to said piston; and

G. means for substantially maintaining said timed relation between said distributor means and said piston when said driven means is selectively operated to vary said angular phase relation between said crankshaft and said camshaft.

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4007723 *Nov 5, 1975Feb 15, 1977Kenneth LaughtonEngine front distributor drive system
US4091776 *Apr 4, 1974May 30, 1978Rockwell International CorporationFluid actuated timing mechanism
US4302985 *Dec 21, 1979Dec 1, 1981Ford Motor CompanyPhase controlling system for two rotatable shafts
US4463712 *Nov 17, 1982Aug 7, 1984Ford Motor CompanyDevice for varying the valve timing of internal combustion engines in correlation to load and speed
US4545338 *Dec 3, 1984Oct 8, 1985Stephen E. LawingCam shaft timing control device
US4708101 *Dec 18, 1985Nov 24, 1987Nissan Motor Co., Ltd.Driving apparatus for intake and exhaust valves of internal combustion engine
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US5507254 *Jun 7, 1995Apr 16, 1996Melchior; Jean F.Variable phase coupling for the transmission of alternating torques
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Classifications
U.S. Classification123/406.11, 464/2, 123/90.18, 123/406.67, 123/90.15, 123/406.73, 123/195.00A
International ClassificationF01L1/344
Cooperative ClassificationF01L1/34406
European ClassificationF01L1/344A1