US3145324A

US3145324A - Centrifugal distributor advance which does not advance the rotor

Info

Publication number: US3145324A
Application number: US197525A
Authority: US
Inventors: Richard T Race
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 1962-05-24
Filing date: 1962-05-24
Publication date: 1964-08-18
Anticipated expiration: 1981-08-18

Description

Aug. 18, 1964 3,145,324

, R. T. RACE CENTRIFUGAL. DISTRIBUTOR ADVANCE WHICH DOES NOT ADVANCE THE ROTOR Filed May 24, 1962 FIG. 1 49 To Vacuum Advance g 6 Vacuum Advance 45 IN VEN TOR.

Richard I Ro'ce United States Patent 3,145,324 FUGAL DISTRIBUTOR ADVANCE WHICH DOES NOT ADVANCE THE ROTOR Richard T. Race, Chicago, 111., assignor taMotorola, Inc, Chicago, 111., a corporation of Illinois Filed May 24, 1962, Ser. No. 197,525 6 Claims. (Cl. 315-212) This invention relates to distributor and timer mechanisms for use in the ignition systems of internal combustion engines, and more particularly to an advance system for such a mechanism.

It is well-known in the distributor art that as the speed of the engine increases it becomes advantageous to supply the spark to the distributor rotor at a time more advanced in the cycle. This is because despite the ncreased number of cylinder firings, the fuel takes the same amount of time to burn. Therefore, maximum engine efficiency requires that the pulse be supplied to the spark plugs proportionally sooner as speed increasas In an ignition system of the magnetic inductive pulsing type, such as that disclosed in the application of Oleh M. Kilritza and Edward V. Havel, Serial No. 101,151, filed April 6, 1961, now abandoned, there is an inherent problem of increased electrical delay. In this type of system, pulses are produced by intermittently causing the flux through coils to increase and decrease. Because the system uses only that portion of the pulse generated by the magnetic flux as the flux is decreasing, a certain amount of electrical delay results.

Conventional advancing arrangements are unsuited-for the large advance needed to offset this electrical delay because they also advance the distributor rotor. Suflicient advance to offset the electrical delay causes the rotor to advance far enough to cause sparking to the wrong electrode whereby engine efficiency is substantially reduced and the distributor electrode deteriorates due to burning.

Accordingly, an object of this invention is to provide an improved low cost distributor and timer mechanism wherein the timer may be advanced substantially more than in prior units.

Another object of the invention is to provide an improved, low cost distributor and timer system in which a rotary member operating a pulsing unit may be advanced independently of the distributor rotor.

A feature of the invention is the provision, in the ignition system of an internal combustion engine, of a pulsing unit having a rotatable armature for operating the same, which armature is coupled to adrive shaft through an advance mechanism so that the armature may be advanced independently of the distributor rotor.

Another feature of the invention is the provision of an ignition system for an internal combustion engine, including a pulsing unit having a rotatable armature for operating the same fixed to a sleeve; and a centrifugal advance mechanism including a base plate fixed to the distributor shaft, a rotary plate fixed to the sleeve, and pivotal flyweights which angularly advance the rotary plate and hence the sleeve and rotatable armature independently of the distributor rotor as the speed of rotation of the distributor shaft increases.

In the drawing:

FIG. 1 is a schematic view of the circuit associated with the invention and includes a top plan view of a portion of a mechanism incorporating the invention;

FIG. 2 is a sectional view taken along the line 22 of FIG. 1; and

FIG. 3 is a sectional view taken along the line 33 of FIG. 2, with part broken away.

3,145,324 Patented Aug. 18, 1964 In accordance with the invention, a distributor and timer unit for use in the ignition system of an internal combustion engine is provided with an improved advancing arrangement. Rotary means for operating the pulse generating system are mounted on the distributor shaft independently of the distributor rotor and are coupled to a centrifugal advance unit. Asa result, the advance unit may angularly advance the rotary means with respect to the distributor shaft and independently of the distributor rotor as the speed of rotation of the distributor shaft in- 1 creases. This permits a wide variation in the amount of advance while at the same time preventing the distributor rotor from advancing too far and sparking to the wrong ignition contact.

The ignition system is illustrated in FIG. 1 for use in an internal combustion engine 10 having a plurality of cylinders which are fired by signals supplied to terminals 11. The engine is mechanically connected to a distributor having a rotary contact 12 which extends from rotor 13 to selectively apply high voltage pulses to contacts 14 connected to terminals 11. The distributor therefore operates at any time that the engine is turning over, whether when operating on its own power or when being cranked by a starter or the like.

The pulsing unit of FIG. 1 includes a permanent mag net 15 having pole pieces 16 connected thereto about which are positioned coils 17. The two coils 17 are connected in series to provide pulses to transistor 21 as will be explained. The permanent magnet and coil assembly are mounted on a dished plate 18 which may be similar to the type used to support the contacts in standard automotive distributors. A toothed magnetic wheel or armature 19 is mounted for rotation so that the teeth 20' thereof pass by and in close proximity to the ends of the pole pieces 16. Armature 19 may be driven by the distributor shaft 43 to rotate with the rotor 13 as will be further explained. The elements just described including magnet 15 and armature 19 are intended, as shown assembled in FIG. 1, to illustrate the appearance of the mechanism when distributor cap 41 and rotor 13 are removed. (See FIG. 2.)

As stated above, the coils 17 are connected in a circuit to provide pulses to the input of transistor 21. Coils 17 are connected in series with resistor 23 between the emitter and base electrodes of transistor 21. Bias potential 1s applied to the emitter electrode of transistor 21 from the bias supply line through the voltage divider circuit including resistor 23, coil 17 and resistor 24 to the base electrode of this transistor. This bias potential causes the transistor 21 to be normally conducting.

The collector electrode of transistor 21 is connected to transformer 25 which applies the pulses from the tran s stor 21 to the transistor 22. Bias is applied to trans1stor 22 to the emitter electrode thereof and through the secondary winding of transformer 25 to the base electrode. Transistor 22 is normally nonconducting and is rendered conducting by the pulse applied between the base and emitter electrodes thereof. Transistor 22 is cut off at the end of the pulse to develop a sharp pulse in the primary winding 31 of transformer 32. This pulse is stepped up in the secondary winding 33 of transformer 32 and applied to the moving distributor contact 12. The pulse is thereby selectively applied to the terminals 11 of the cylinders of the internal combustion engine.

It will be apparent from FIG. 1 that when armature 19 is positioned so that a tooth20 thereof is between the ends of the pole pieces 16, the flux through the coils 17 will be minimum. As the armature rotates, so that the teeth 19 first approach, then become aligned with, and finally pass away from the ends of pole pieces 16, the value of the fiux through coil 17 will first increase to a maximum value and then decrease to the minimum. This change in flux through the coils 17 as armature 19 rotates will develop voltage across the coils. Because of the conduction of the transistor 21, the voltage applied between the base and emitter will not rise during the first half of the cycle, but the negative portion of the cycle of the voltage produced in coil 17 will cause the transistor 21 to be cut off.

The voltage between the collector of transistor 21 and ground will be positive when the transistor conducts and will swing negative when the transistor is cut off. This voltage is applied through transformer 25 between the base and emitter circuit of transistor 22 and is reversed in phase to provide a positive pulse thereto. As previously stated, transistor 22 is normally nonconducting. However, the voltage applied between the base and emitter electrodes thereof during the second half of the cycle will cause the transistor 22 to be driven first to saturation and then back to cutoff to provide a sharp pulse in the primary winding 31 of transformer 32. This pulse is stepped up in the transformer 32 to provide an extremely high voltage at the movable distributor 12.

The dished plate 18 of the pulsing unit on which the coils 17 are mounted is commonly called the advance plate of the distributor and may be advanced or retarded with respect to the rotating disc 1?. This operation may be controlled by a vacuum advance, as indicated by drive rod 35, and regulates the time of firing of the cylinder with respect to the movement of the pistons therein. The vacuum advance may operate from the butterfly valve in the carburetor of the internal combustion engine so that an immediate advance will take place when a sudden variation in throttle opening occurs to compensate for the greater amount of fuel entering the cylinders. As the vacuum decreases at the butterfly valve, the advance plate will gradually return to its original position. However, since the engine speed is increasing, the centrifugal advance mechanism, which will be explained below, compensates to effectively maintain the advance. Thus, the vacuum advance serves as a supplement to the centrifugal advance.

Referring now to FIGS. 2 and 3, a distributor shaft 43, which may be driven by the engine 1th, extends through a lower housing 45 and drives rotor 13 directly fixed to its upper end. Distributor cap 41 clamps to lower husing 45 and contains a rotor contact 48 which is connected to the secondary winding 33 of transformer 32 as shown in FIG. 1. Contacts 14 extend inwardly and down from distributor cap 41 and are positioned so that distributor contact 12 will pass extremely close thereto. Thus, rotor 13 containing distributor contact 12 rotates with the shaft 43 to selectively complete a circuit to contacts 14 and conduct pulses thereto.

The armature 19 of the pulsing unit, which has been described, is fixed on a tubular sleeve or shaft 47 which is concentrically mounted on shaft 43. Also fixed to sleeve 47 is armature plate 49 which, as shown in FIG. 1, contains a pair of elongated slots 51 which are disposed transversely to a radius of plate 49. A drive plate 53 is fixed to shaft 43 and is rotatable therewith. Pivotally mounted on plate 53 are a pair of flyweights 55 and '7 which are spring biased to an inward position by means of coil springs 59 and 61, fixed to

posts

63 and 65 extending from plate 53. Flyweights 55 and 57 have

drive posts

67 and 65 respectively-extending therefrom. These drive posts extend through slots 51 in plate 49 and provide a driving contact with the plate 49, sleeve 47 and armature 19, causing these latter three elements to rotate with shaft-43.

As the speed of shaft 43 increases, fiyweights 55 and 57 will pivot outwardly due to centrifugal force against the bias of springs 59 and 61 respectively. This causes movement of

posts

67 and 69 and slots 51 Which displaces plate 49 and hence sleeve 47 and armature 19 angularly with respect to the shaft 43. The result is that armature 19 is advanced with respect to the shaft 45 and rotor 13, thereby causing the coils 17 to produce a pulse proportionally sooner. By such an arrangement, armature 19 may be advanced sufiiciently to offset electrical delay without, at the same time, advancing rotor 13. Greater advance is possible than in previous systems because to advance armature 19 the sufficient amount with a previous mechanism would result in excessive advance of rotor 13 and cause the spark to jump from distributor contact 12 to the wrong one of contacts 14.

It may therefore be seen that the invention provides an improved low cost distributor and timer unit in which the rotary member operating the pulsing unit may be advanced independently of the distributor rotor, thereby malringit possible to use a substantially greater advance than prior units.

I claim:

1.'A distributor and timer unit for use with the magnetic ignition pulser of an internal combustion engine having cylinders with associated ignition means, said unit including in combination, a rotary drive shaft, rotary means driven by said shaft for operating the magnetic ignition pulser, advance means mechanically coupling said rotary means to said shaft for angularly displacing said rotary means with respect to said shaft as the speed of rotation of said shaft varies, and rotary conductor means electrically connectable to the ignition pulser and directly fixed to and driven by said shaft for selectively applying pulses from the ignition pulser to the ignition means of the cylinders.

2. An ignition system for use with an internal combustion engine having ignition means, including in combination, a rotary drive shaft, pulse generating means including a rotary Wheel for operating said pulse generating means, centrifugal advance means mechanically coupling said rotary wheel to said shaft for angularly advancing said rotary Wheel with respect to said shaft as the speed of rotation of said shaft increases, and rotary conductor means electrically connected to said pulse generating means and directly fixed to and driven by said shaft for selectively applying pulses from said pulse generating means to the ignition means of the engine, with said pulses being applied to the ignition means independently of the advance of said rotary Wheel.

3. An ignition system for use with an internal combustion engine having a plurality of cylinders with associated ignition means, including in combination, a rotary drive shaft, pulse generating. means including a rotary Wheel for operating'said pulse generating means, centrifugal advance means mechanically coupling said rotary wheel to said shaft, said advance means including a rotary plate and means coupling said plate to said rotary wheel so that said advance means will angularly advance said wheel with respect to said shaft as the speed of rotation of said shaft increases, a plurality of contacts arranged in a circular order and connected to the ignition means of the engine, and rotary conductor means electrically connected to said pulse generating means and directly fixed to and driven by said shaft for selectively applying ignition pulses to said contacts for application to the ignition means of the engine.

4. An ignition system for use with an internal combustion engine having ignition means, including in combination, a rotary drive shaft, magnetic pulse generating means including a rotary wheel for operating said pulse generating means, a rotatable sleeve concentrically mounted on said shaft and fixed tosaid rotary Wheel for driving the same, a centrifugal advance mechanism including a base plate fixed to said shaft and a rotary plate fixed to said sleeve and further including pivotal means coupling said base plate to said rotary plate, said pivotal means being displaceable by centrifugal force acting thereon due to increased rotational speed to angularly advance said sleeve and said rotary wheel with respect to said shaft as the speed of rotation of said shaft increases, and rotary conductor means electrically connected to said magnetic pulse generating means and directly fixed to and driven by said shaft for selectively applying pulses to the ignition means of the engine.

5. An ignition system for use with an internal combustion engine having ignition means, including in combination, a rotary drive shaft, pulse generating means including magnetic means and coil means and a rotary magnetic wheel for varying the' flux through said coil means to produce a voltage pulse therein, a rotatable sleeve concentrically mounted on said shaft and fixed to said magnetic wheel for driving the same, a centrifugal advance mechanism including a base plate fixed to said shaft and a rotary plate fixed to said sleeve and further including pivotal means coupling said base plate to said rotary plate, said pivotal means being displaceable by centrifugal force acting thereon due to increased rotational speed to angularly advance said sleeve and said magnetic wheel with respect to said shaft as the speed of rotation of said shaft increases, and rotary conductor means electrically connected to said pulse generating means and directly fixed to and driven by said shaft for selectively applying pulses from said pulse generating means to the ignition means of the engine.

6. An ignition system for use with an internal combustion engine having ignition means, including in combination, a'rotary drive shaft, pulse generating means including magnetic means and coil means and a rotary magnetic wheel for intermittently causing an increase and decrease in the flux density through said coil means to produce a voltage pulse therein, said pulse generating means further including circuit means utilizing that portion of the volt-age pulse produced in said coil means as the flux density through said coil means is decreasing, ad-' vance means mechanically coupling said magnetic wheel to said shaft for angularly advancing said magnetic wheel with respect to said shaft as the speed of rotation of said shaft increases, and rotary conductor means electrically connected to said pulse generating means and directly fixed to and driven by said shaft for selectively applying pulses from said pulse generating means to the ignition means of the engine,'whereby said advance means moves tooffset electrical delay of said pulse producing means without causing said rotary conductor means to advance.

Colvin May 13, 1952 Hartman Nov. 27, 1953

Claims

1. A DISTRIBUTOR AND TIMER UNIT FOR USE WITH THE MAGNETIC IGNITION PULSER OF AN INTERNAL COMBUSTION ENGINE HAVING CYLINDERS WITH ASSOCIATED IGNITION MEANS, SAID UNIT INCLUDING IN COMBINATION, A ROTARY DRIVE SHAFT, ROTARY MEANS DRIVEN BY SAID SHAFT FOR OPERATING THE MAGNETIC IGNITION PULSER, ADVANCE MEANS MECHANICALLY COUPLING SAID ROTARY MEANS TO SAID SHAFT FOR ANGULARLY DISPLACING SAID ROTARY MEANS WITH RESPECT TO SAID SHAFT AS THE SPEED OF ROTATION OF SAID SHAFT VARIES, AND ROTARY CONDUCTOR MEANS ELECTRICALLY CONNECTABLE TO THE IGNITION PULSER AND DIRECTLY FIXED TO AND DRIVEN BY SAID SHAFT FOR SELECTIVELY APPLYING PULSES FROM THE IGNITION PULSER TO THE IGNITION MEANS OF THE CYLINDERS.