US3301973A

US3301973A - Distributor with vacuum and electromechanical advance

Info

Publication number: US3301973A
Application number: US446327A
Authority: US
Inventors: Louis A Bevacqua
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 1965-04-07
Filing date: 1965-04-07
Publication date: 1967-01-31
Anticipated expiration: 1984-01-31

Description

Jan. 31, 1967 L. A. BEVACQUA DISTRIBUTOR WITH VACUUM AND ELECTROMECHANICAI- ADVANCE Filed April 7, 1965 I2 PW" FIG. 2

FIG. 4

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vAcuuM IN INCHES United States Patent 6 3,301,973 DISTRIBUTOR WITH VACUUM AND ELEQTRO- MECHANKCAL ADVANCE Louis A. Bevacqua, Des Plaines, Ill., assignor to Motorola, Inc, Franklin Park, lill., a corporation of Illinois Filed Apr. 7, 1965, Ser. No. 446,327 8 Claims. (Cl. 200-311) This invention pertains generally to an electromechanical advance mechanism and more particularly to an electromechanical advance mechanism for the ignition timer of an auto-mobile engine, which advances and retards the timer at different engine speeds.

Reduction of smog in large cities has become an increasingly important problem. To meet this problem it is highly desirable that automobile engines be designed to operate so that hydrocarbons which are emitted in the exhaust from the engine are substantially reduced. One way to reduce this emission of hydrocarbons in the exhaust is by retarding the engine ignition timing during the time that the car is idling, for instance, when stopped at heavy traffic or at a traffic light.

Present ignition timers have the spark advance set at the manufacturers recommended position for starting, and then advance the spark in response to increased engine r.p.m. Therefore, the engine ignition timing is the same during idling as at starting, or slightly advanced .with respect to the starting position. To retard the timwhich can be produced at reasonable cost.

It is, therefore, an object of this invention to provide a simple and improved electromechanical advance mechanism for an automobile advance ignition timer.

Another object of this invention is toprovide an electromechanical advance mechanism for an engine ignition timer that can be produced at reasonable cost which .provides starting of an automobile engine at the optimum timing, retarding the ignition timing while idling, and then advancng the engine timing with increased engine vacuum for high speed operation.

A feature of this invention is the provision of an electromechanical advance mechanism having a rotatable member, a spring for moving the member to a given position in one direction, an electromagnet for rotating the member away from the given position, and a vacuum servo for providing controlled movement of the member away from the given position.

Another feature of the invention is the provision of an advance mechanism for an ignition system of an internal combustion engine including a rotatable advance plate, an electromagnet for holding the plate in a position optimum for starting of the engine, a spring for retarding the plate with respect to the starting position during idling of the engine, and a vacuum servo for advancing the plate as the engine speed increases. The electromagnet may include a coil on a magnetic structure having poles cooperating with pole portions on the rotatable plate, or may be a solenoid with a movable core which is coupled to the rotatable plate.

In the drawings:

FIG. 1 is a plan view of the electromechanical advance mechanism -for an ignition time-r using an electromagnet, with the position for engine starting shown in dotted lines;

FIG. 2 is a side elevation of the same mechanism as shown in FIG. 1;

FIG. 3 is a plan view of the electromechanical advance mechanism for an ignition timer using an electr 2.3mm

Patented Jan. 31, 1967 tric solenoid, with the position for engine starting shown in dotted lines;

FIG. 4 is a side elevation of the same mechanism as shown in FIG. 3; and

FIG. 5 is a graph illustrating the operation of the mechanism of the invention.

In accordance with this invention an electromechanical advance mechanism is provided for an ignition timer of an internal combustion engine and includes a fixed member and an advance plate supporting a pulsing mechanism and which is rotatable with respect to the fixed member. An electroma-gnet supported on the fixed member is operative to move the rotatable plate to a position providing optimum timing for starting of the engine. A spring is connected to the movable plate and is operative when the solenoid is tie-energized to retard the rotatable plate to provide optimum timing of the pulsing mechanism during idling of the engine. A vacuum servo of the type commonly used in ignition timers is connected to the plate for advancing the same as the speed of the engine increases. The solenoid is coupled to and energized with the starting mechanism for the engine so that the timer is advanced to the optimum position for starting. When the starting mechanism is de-energized, the spring causes the timer to assume the position for idling, and when the engine speed increases the vacuum servo advances the timer in accordance with the engine speed.

The electromagnet structure for rotating the advance plate to the starting position may include a coil and core having poles cooperating with .pole portions on the rotatable advance plate, so that when the coil is energized the advance plate is brought to the position for starting. In another embodiment, the electromagnet may be a solenoid having a movable armature which is coupled to the advance plate and which moves the same to the starting position when the solenoid is energized.

The device of the invention is described for use as an electromechanical advance mechanism for an automobile engine timer. device may find utility in other applications where an electromagnetic advance mechanism is desirable.

In FIGS. 1 and 2, a first fixed support member or plate 10 is the base of the housing 14 of the device. A drive shaft 12 extends coaxially and rotatably within the housing 14. A cam 15 on the drive shaft 12 has a shoulder 17 which is in rotatable contact with the bearing surface or bush 119. A second or breaker plate 22 has an aperture 24 through which bush 19 passes. Plate 22 is rotatably and coaxially mounted with respect to plate 10 and housing 14 and carries the ignition timing points 20. The points 20 may be statistically adjusted with respect to the cam 15 by the screw 21 cooperating with slot 23. As the drive shaft 12 turns inside the housing 14, the cam 15 is turned to operate the ignition timing points 20 in the known manner.

A vacuum servo body 25 is fixedly mounted by brackets 26 to the housing 14. The servo body 25 has an inlet 27 connected to the vacuum line (not shown) extending from the engine intake manifold, as is Well known to those familiar with the art; The vacuum in the servo body, therefore, varies in the same sense as the crank shaft r.p.m. of the engine. A spring 30 is inserted be tween the diaphragm 32 and the wall 34 of the servo body 25. The spring 30 biases the diphragm 32 to oppose movement of the diaphragm 32 towards the vacuum side 36 of the servo 25. This spring 30 regulates the advance of the mechanism as will be described.

The breaker plate 22 has a magnetic portion 38 with first and

second pole pieces

40 and 41 respectively, and a portion with an arcuate slot 43. An electromagnet 45 is fixedly mounted by brackets 46 to the first plate It should be understood that this.

10, and has

pole portions

48 and 49, respectively psitioned in cooperative relation with the

pole pieces

40 and 41 of the plate 22.

A rod 50 has one end connected to the diaphragm 32 at 52 and a second end having a right angle extension 54 that is slidably engageable with the slot 4 3.

Spring posts

56 and 57 extend from the fixed plate and the breaker plate 22 respectively. A spring 58 is connected between the

protrusions

56 and 57 and biases the breaker plate 22 to a first position with respect to the fixed plate 10 against the right angle extension 54 which also functions as a stop.

The full lines in FIG. 1 indicate the first position of the device with the engine stopped. At this point the timing is set at a position which is retarded, for instance 10", from the manufacturers recommended position for starting. When the starter switch 60 is closed, the electromagnet 45 is energized, attracting the

pole pieces

40 and 41 to the

pole portions

48 and 49, thereby advancing the breaker plate 22 to the manufacturers recommended position for starting indicated by the dotted line at 62. As the breaker plate 22 advances, the rod 50 is disengaged from the plate 22 and slides in the slot 43 in order to permit free movement of plate 22. When the motor is idling, the starter switch 60 is opened which de-energizes the electromagnet 45. The spring 58 then acts to return the breaker plate 22 to the first position against right angle extension 54 of rod 50, resulting in the engine idling, for example, at 300600 r.p.m., with the ignition timing retarded 10".

With the engine idling, the vacuum in the servo body 25 is insuflicient to overcome the bias of

springs

30 and 58 to move the diaphragm 32 towards the vacuum side 36 of the servo 25. However, when the engine r.p.m. is increased above idling, the vacuum in the servo varies in the same way. This increases the pressure diiferential on either side of the diaphragm 32. When this pressure differential is great enough to overcome the tension of diaphragm return spring 30 and spring 58, the diaphragm 32 will move toward the vacuum side 36 of the servo 25 and draw rod 50 with it. This motion of rod 50 slidably engages the right angle extension 54 with the breaker plate 22 and moves the plate 22, hence points 20, in the direction to advance the ignition timing. The pressure of diaphragm return spring 30 is reduced somewhat from the standard diaphragm return spring generally used with vacuum servo advance mechanisms. This was necessary to provide a rapid advance above idle to the recommended timing for acceleration. Once the timing has been returned to the standard advance position for a given r.p.m., the pressure spring 58 cooperates with spring 30 to maintain recommended timing for continued acceleration.

During periods of zero vacuum, for instance, when the throttle is wide open or closed, the timing would be retarded 10 from the manufacturers recommended position. This, however, could be controlled by throttle settings, relays, and other known methods.

FIGS. 3-4 show a second embodiment of the invention. In this embodiment the

pole pieces

40 and 41 and an electromagnet 45 are replaced by a solenoid 70 which has a floating core 72 and is fixedly mounted to fixed plate 10 by bracket 71. A rod 74 has one end connected to the core 72 at 75 and the other end, which has a right angle extension 76, extends through the breaker plate 22, and is fixed in place by crescent shaped lock washer 77.

The full lines in FIG. 3 indicate the first position of the device with the engine stopped. At this point the timing is set at a position which is retarded, for instance, 10 from the manufacturers recommended position for starting. When the starter switch 60 is closed, the solenoid 70 is energized and attracts the core 72 which moves the rod 74. The movement of rod 74 in turn rotates the breaker plate 22, advancing the ignition tim- 'vance and retarding action of this invention.

ing to the manufacturers recommended position for starting indicated by the dotted line at 80. As the breaker plate 22 advances, the rod 50 is disengaged from the plate 22 and slides in the slot 43 in a fashion similar to that of the first embodiment, in order to permit free movement of the plate 22. When the motor is idling, the starter switch 60 is opened to de-energize the solenoid 70. The spring 58 then acts to return the breaker plate 22 to the first position, resulting in the engine idling, for example, at 300 to 600 r.p.m. with the ignition timing retarded 10. The remainder of the operation of the electromechanical advance mechanism is similar to that operation described for the first embodiment.

The operation of this invention may be better understood by referring to the graph of FIG. 5. The. change of flywheel degrees is plotted against the change in vacuum in inches of mercury, with the dotted lines indicating the standard advance recommended by the manufacturer, and the solid line 92 indicating the ad- Using a standard ignition advance mechanism, the engine of the vehicle is started with the ignition timing as indicated at 94 and remains at the recommended position for starting during the idle range, or until the vacuum is about five inches as indicated at 96. At this point the timing is advanced by increased vacuum in the same sense as the engine r.p.m. along line 97.

With the electromechanical advance mechanism of this invention, however, the vehicle is started at the manufacturers recommended position for starting 94. The timing remains in this position during cranking or until about two inches of mercury (point 98). When the cranking motor is de-energized, the ignition timing is retarded 10 (point 99) by the action of the spring 58 moving the breaker plate 22 in the manner previously described. The curve between

points

99 and 100 is relatively flat representing the period where the vacuum is increased from the idling range but is still not great enough to overcome the tension of

springs

30 and 58 to advance the timing. However, because the tension of spring 30 is reduced from the standard spring, a slight increase in vacuum (point 100) from the idling range causes the ignition timing to be rapidly advanced. This is shown by line 92 which continues to rise rapidly until the two curves merge (point 102). From point 102, the timing is advanced in accordance with the manufacturers recommendation.

What has been described, therefore, is an improved electromechanical advance mechanism that makes it possible to start an engine at the manufacturers recommended timing, and then retard the engine timing below that of the manufacturers recommended position while idling, and then advancing the engine timing in accordance with the manufacturers recommendation.

Iclaim:

1. An electromechanical advance mechanism for use with an ignition timer for an automobile engine and for actuation by the engine starter switch and by vacuum taken from the automobile engine which varies in the same sense as the engine r.p.m., the mechanism including in combination, a first fixed plate, a breaker plate rotatably mounted with respect to said first plate, spring means coupled to said breaker plate and tending to hold the same in a given position to retard the engine ignition timing past the optimum position for starting the engine, electromagnet means mounted on said fixed plate and coupled to said breaker plate from said retarded position to advance spring means with respect to said first fixed plate, a vacuum actuated diaphragm, and linking means coupling said diaphragm to said breaker plate, said electromagnet being coupled to and initially energized in response to operation of the engine starter switch and acting to rotate said breaker plate from said'retarted position to advance the engine ignition timing to an optimum position for starting the same, said spring means acting to return said breakerplate to said retarded position with the engine idling and upon de-energizing of said electromagnet to reduce the emission of hydrocarbons from the engine, said diaphragm being responsive to vacuum produced by the engine when operating above idling speed, and acting throughsaid linking means to move said breaker plate to advance the engine ignition timing.

2. An electromechanical advance mechanism for use with an ignition timer for an automobile engine, and responsive to the engine starter switch, and to vacuum taken from the automobile engine which varies in the same sense as the engine r.p.m., such mechanism including in combination, support means, a breaker plate rotatably mounted with respect to said support means, vacuum actuated means including a diaphragm and linking means coupling said diaphragm to said breaker plate, stop means integral with said breaker plate for receiving said linking means, spring means coupled to said breaker plate and tending to hold the same in a given position to retard the ignition timing past the optimum position for starting the engine with said linking means engaging said stop means, electromagnet means mounted to said support means and being coupled to said breaker plate for rotating the same away from said given position against said spring means and disengaging said linking means from said stop means, said electromagnet being coupled to and energized in response to operation of the engine starter switch for rotating said breaker plate from said given position to advance the engine ignition timing to an optimum position for starting the same, said spring means retarding said breaker plate and returning the same to said given position upon de-energizing of said electromagnet during idling of the engine to reduce the output of hydrocarbons therefrom, said diaphragm being responsive to vacuum produced by the engine when operating above idling speed and acting through said linking means to move said advance plate away from said stop means to advance the engine ignition timing.

3. An electromechanical advance mechanism including in combination a first fixed plate, a second plate rotatably mounted with respect to said first plate, spring means coupled to said second plate and tending to hold the same in a given position, said second plate having a magnetic portion with first and second pole pieces, an electromagnet fixedly mounted with respect to said first plate and having pole portions positioned in cooperative relation with said first and second pole pieces of said second plate, a vacuum actuated diaphragm, and linking means coupling said diaphragm to said second plate, said electromagnet when energized attracting said pole pieces to said pole portions to rotate said second plate against said spring means in one direction from said given position, said spring means returning said second plate to said given position with respect to said first plate upon de-energization of said electromagnet, said diaphragm being responsive to vacuum and acting through said linking means to move said second plate in said one direction.

4. An electromechanical advance mechanism for use with a vacuum servo for an engine ignition timer having a body and a spring return diaphragm, said mechanism including in combination a first fixed plate, a breaker plate ro-tatably mounted with respect to said first plate, said breaker plate having a magnetic portion with first and second pole pieces and a portion with an arcuate slot therein, an electromagnet fixedly mounted with respect to said first plate and having pole portions positioned in cooperative relation with said first and second pole pieces of said breaker plate, a rod having one end connected to the diaphragm and a second end slidably engaging said arcuate slot for moving said breaker plate, said first plate and said breaker plate each having a spring post extending therefrom, and a spring connecting said spring posts and biasing said breaker plate to a first position with respect to said first plate, said electromagnet when energized attracting said pole pieces to said pole portions to rotate said breaker plate in one direction against said spring pressure from said first position, with said second end Off said rod sliding in said arcuate slot, said spring acting to return said breaker plate to said first position with respect to said first plate upon de-energization of said electromagnet, the diaphragm of the servo being responsive to vacuum in the servo body to move said rod to engage said breaker plate and move the same against the bias of said spring in said one direction.

5. An electromechanical advance mechanism for use with a vacuum servo for an automobile ignition timer having a body and a spring return diaphragm, and for actuation by the engine starter switch and vacuum taken from the automobile engine which varies in the same sense as the engine rpm, the mechanism including in combination, a first fixed plate, a breaker plate mounted with respect to said first plate, said breaker plate having a magnetic portion with first and second pole pieces and a portion with an arcuate slot therein, an electromagnet fixedly mounted with respect to said first plate and having pole portions positioned in cooperative relation with said first and second pole pieces of said breaker plate, a rod having one end connected to the diaphragm and a second end slidably engaging said arcuate slot for moving said breaker plate, said first plate and said breaker plate each having a-spring post extending therefrom, and a spring connecting said spring posts and biasing said breaker plate to retard the engine ignition timing, said electromagnet when energized by the starter switch attracting said pole pieces to said pole portions to rotate said breaker plate against said spring bias from said retarded position to advance the engine ignition timing, with said second end of said rod sliding in said arcuate slot, said spring acting to return said breaker plate to said retarded position with the engine idling and upon de-energization of said electromagnet, the diaphragm of the servo being responsive to vacuum in the servo body to move said rod to engage said breaker plate and rotate the same against said bias of said spring when the engine is at some -r.p.m. greater than idling to advance the engine timing from said retarded position.

6. An electromechanical advance mechanism including in combination, a first fixed plate, a second plate rotat-ably mounted with respect to said first plate, spring means coupled to said second plate and tending to hold the same in a given position, a solenoid including a floating core fixedly mounted with respect to said first plate, a rod for moving said second plate having one end connected to said core and a second end connected to said second plate, a vacuum actuated diaphragm, and linking means coupling said diaphragm to said second plate, said solenoid when energized attracting said core and moving said rod to rotate said second plate against said spring pressure in one direction from said given position, with said second plate returning to said given position with respect to said first plate upon de-energization of said solenoid, said diaphragm being responsive to vacuum and acting through said linking means to move said second plate in said one direction.

7. An electromechanical advance mechanism for use with a vacuum servo for an engine ignition timer having a body and a spring return diaphragm, said mechanism including in combination a first fixed plate, a breaker plate mounted with respect to said first plate and having an arcuate slot therein, a solenoid including a floating core fixedly mounted with respect to said first plate, a first rod for moving said breaker plate having one end connected to said core and a second end connected to said breaker plate, a second rod having one end connected to the diaphragm and a second end slidably engaging said a-rcuate slot for moving said breaker plate, said first plate and said breaker plate each having a spring post extending therefrom, a spring connecting said spring posts and biasing said breaker plate to a first position with respect to said first plate to retard the ignition timing past the position for optimum starting, said solenoid when energized attracting said core and moving said first rod to rotate said breaker plate against saidspring bias in one direction from said first position to advance the ignition timing to an optimum position for starting the engine, with said second end of said second rod sliding in said arcuate slot, with said engine idling said spring acting to return said breaker plate to said first position with respect to said first plate upon de-energization of said solenoid thereby reducing the output of hydrocarbons from the engine, the diaphragm of the servo being responsive to vacuum in the servo body to move said second rod to engage said breaker plate and move said breaker plate against said bias of said spring in said one direction to advance the ignition timing.

8. An electromechanical advance mechanism for use with a vacuum servo for an automobile ignition timer having a body and a spring return diaphragm and responsive to operation of the engine starter switch and to vacuum taken from the automobile engine which varies in the same sense as the engine rpm, the mechanism including in combination, support means, a breaker plate mounted with respect to said support means and having an arcuate slot therein, a solenoid including a floating core fixedly mounted with respect to said support means, a first rod for moving said breaker plate having one end connected to said core and a second end connected to said breaker plate, a second rod having one end connected to the diaphragm and a second end slidably engaging said arcuate slot for moving said breaker plate, said support means and said breaker plate each having a spring post extending therefrom, a spring connecting said spring posts and biasing said breaker plate in a position with said second end of said second rod engaging the end of said arcuate slot to retard the engine ignition timing past the optimum position for starting the engine, said solenoid when energized in response to operation of the starter switch attracting said core and moving said first rod to rotate said breaker plate against said spring bias from said retarded position to advance the engine ignition timing to an optimum position for starting the engine, with said second end of said second rod sliding in said arcuate slot, said spring acting to return said breaker plate to said retarded position with the engine at idling and upon reenergization of said solenoid to reduce the output of hydrocarbons from the engine, the diaphragm of the servo being responsive to vacuum in the servo body produced by the engine when operating above idling speed to move said second nod to engage said breaker plate and rotate the same from said retarded position against said bias of said spring to advance the engine ignition timing.

References (Iited by the Examiner UNlTED STATES PATENTS 1,071,373 8/1913 Varley 123-146 2,991,338 7/1961 Mason 2()031 3,105,479 10/1963 DeW '123146 BERNARD A. GILHEANY, Primary Examiner.

G. MAIER, Assistant Examiner.

Claims

1. AN ELECTROMECHANICAL ADVANCE MECHANISM FOR USE WITH AN IGNITION TIMER FOR AN AUTOMOBILE ENGINE AND FOR ACTUATION BY THE ENGINE STARTER SWITCH AND BY VACUUM TAKEN FROM THE AUTOMOBILE ENGINE WHICH VARIES IN THE SAME SENSE AS THE ENGINE R.P.M. THE MECHANISM INCLUDING IN COMBINATION, A FIRST FIXED PLATE, A BREAKER PLATE ROTATABLY MOUNTED WITH RESPECT TO SAID FIRST PLATE, SPRING MEANS COUPLED TO SAID BREAKER PLATE AND TENDING TO HOLD THE SAME IN A GIVEN POSITION TO RETARD THE ENGINE IGNITION TIMING PAST THE OPTIMUM POSITION FOR STARTING THE ENGINE, ELECTROMAGNET MEANS MOUNTED ON SAID FIXED PLATE AND COUPLED TO SAID BREAKER PLATE FROM SAID RETARDED POSITION TO ADVANCE SPRING MEANS WITH RESPECT TO SAID FIRST FIXED PLATE, A VACUUM ACTUATED DIAPHRAGM, AND LINKING MEANS COUPLING SAID DIAPHRAGM TO SAID BREAKER PLATE, SAID ELECTROMAGNET BEING COUPLED TO AND INITIALLY ENERGIZED IN RESPONSE TO OPERATION OF THE ENGINE STARTER SWITCH AND ACTING TO ROTATE SAID BREAKER PLATE FROM SAID RETARDED POSITION TO ADVANCE THE ENGINE IGNITION TIMING TO AN OPTIMUM POSITION FOR STARTING THE SAME, SAID SPRING MEANS ACTING TO RETURN SAID BREAKER PLATE TO SAID RETARDED POSITION WITH THE ENGINE IDLING AND UPON DE-ENERGIZING OF SAID ELECTROMAGNET TO REDUCE THE EMISSION OF HYDROCARBONS FROM THE ENGINE, SAID DIAPHRAGM BEING RESPONSIVE TO VACUUM PRODUCED BY THE ENGINE WHEN OPERATING ABOVE IDLING SPEED, AND ACTING THROUGH SAID LINKING MEANS TO MOVE SAID BREAKER PLATE TO ADVANCE THE ENGINE IGNITION TIMING.