GB2028589A - Distributor for multiple cylinder internal combustion engine - Google Patents

Abstract

A distributor for use in multiple cylinder internal combustion engines has a plurality of discharge electrodes 14a, 14F connected respectively to ignition plugs of cylinders divided into two or more groups, each group including a plurality of discharge electrodes 14a or 14F arranged at regular intervals on the circumference of a circle and a rotor head electrode 13, 16 rotatably disposed at the center of these discharge electrodes. Voltage from the secondary winding of an ignition coil is supplied alternately to the rotor head electrodes 13, 16 by a spark discharge change-over means 19, 20a, 20b, and then applied from the selected rotor electrode 13, 16 to one of the ignition plugs. The arrangement permits a wide angular spacing between successive electrodes 14 or 16. <IMAGE>

Description

SPECIFICATION Distributor for multiple cylinder internal combustion engine The present invention relates to a distributor for a multiple cylinder internal combustion engine provided with distributing parts for distributing a secondary voltage generated in an ignition coil to a predetermined one of ignition plugs.

In a conventional distributor of this kind for a multiple cylinder internal combustion engine, a rotor head electrode is fixed on a rotary shaft which is rotated in synchronism with the rotation of the engine and discharge electrodes equal in number to cylinders are fixed on the inner circumference of a distributor cap enclosing a region in which the rotor head electrode is rotated, so that the secondary voltage generated in an ignition coil is directly led to the rotor head electrode so as to be distributed through a predetermined one of discharge electrodes to which the rotor head electrode comes close, to a predetermined one of ignition plugs which is connected to the predetermined one discharge electrode.

In general, the rotor head electrode and the respective discharge electrodes are positioned such that the rotor head electrode is most close to each discharge electrode not at the top dead point of the engine but at a point deviated from the top dead point by an advance or lag angle corresponding to an ignition time which is most frequently used. Therefore, the rotor head electrode and each discharge electrode will be deviated in position from each other at other ignition times than that most frequently used mentioned above.

In conventional intemal combustion engines of this kind, such a control as to advance or delay the ignition time is conducted by means of a combination of a centrifugal spark advance system and a vacuum spark advance system, a combination of a centrifugal spark advance system and an electric spark lag system, an elecronic spark advance/lag system making use of a microcomputer, or the like. In this case it is required to enlarge the range of the control effected so as to increase the output of the engine, to save the fuel, and to reduce the amount of harmful ingredient contained in the exhaust gas.

For example, when the engines are operated at a high speed, the ignition has to be effected in the vicinity of the point which lies before the top dead point by an angle of 1 5 degrees, and when a rapid warming-up of the engine is desired in -the period of idling, the ignition is required to be made in the vicinity of the point which lies after the top dead point by an angle of 1 5 degrees.Accordingly, in the case where the rotor head electrode and the respective discharge electrodes are positioned such that the rotor head electrode will be most close sequentially to the respective discharge electrodes one after another in the vicinity of that point of 1 5 degrees before the top dead point which is frequently used, the secondary voltage of the ignition coil will be distributed sequentially to the respective ignition plugs at positions of the rotor head electrode where the rotor head electrode deviates from each discharge electrode by 30 degrees in angle of rotation when it is required for the ignition to be made in the vicinity of the'point of 1 5 degrees after the top dead point. The above-mentioned angle of 30 degrees are equal to one half of a central angle of 60 degrees formed by adjacent discharge electrodes in the case of a 6-cylinder engine.

Accordingly, the distances from the rotor head electrode to adjacent two of the discharge electrodes through one of which the secondary voltages to be distributed are eq'ual to each other and thus there is a certain danger of the secondary voltage being applied not to the desired discharge electrode but the adjacent one. That is, there is a possibility of the secondary voltage being distributed through the adjacent discharge electrode to a different ignition plug associated thereto.

Further, when conditions such as the number of rotation, the temperature of engine, the negative pressure of intake manifold, etc. are put in a special state, the ignition will has to be effected in the vicinity of the point which lies before the top dead point by an angle of 60 degrees. In this case, if the rotor head electrode and the respective discharge electrodes are positioned such that the rotor head electrode will be most close sequentially to the respective discharge electrode one by one at the point of 15 degrees before the top dead point, the secondary voltage will be generated at positions of the rotor head electrode lying before the positions where the rotor headelectrode will be most close sequentially to the respective discharge electrodes by 45 degrees in angle of rotation.Since, as described previously, the central angle formed by adjacent two discharge electrodes is equal to 60 degrees in the case of 6-cylinder engine, when the rotor head electrode is placed at a position which lies before a desired one of the discharge electrodes by an angle of 45 degrees, the difference in angle between the rotor head electrode and the preceding discharge electrode becomes equal to 1 5 degrees. As a result, the secondary voltage is not led to the desired discharge electrode, but is distributed through the preceding discharge electrode to a different ignition plug associated thereto. Thus, the wrong distribution of electricity takes place.

In order to prevent such wrong distribution, the following counterplan may be thought. That is, the diameter of a distributor cap for mounting discharge electrodes is suitably increase in accordance with the number of cylinders to increase the distance between adjacent discharge electrodes while having the same center angle thereof. However, the above-mentioned counterplan cannot fundamentally solve the problem of such a wrong distribution, since the difference in angle between adjacent discharge electrodes is left unchanged. Such a counterplan will rather produce a drawback that the diameter of the distributor has to be increased resulting in an increased dead space thereof which causes difficulty in installation of the distributor with an engine room.

Therefore, it is an object of the present invention to provide a distributor for a multiple cylinder internal combustion engine which does not give rise to the wrong distribution of electricity arising in prior art distributors.

It is another object of the present invention to provide a distributor which can prevent the wrong distribution of electricity without increasing the dead space of the distributor.

It is a further object of the present invention to provide a distributor suited to be combined with an electronic spark timing control system which is equipped with a microcomputer and has a wide controllable range of advance/lag angle of ignition time.

In order to attain these and other objects, according to an aspect of the present invention, there is provided a distributor for a multiple cylinder internal combustion engine comprising a plurality of distributing parts one of which is provided with a part of discharge electrodes connected respectively to ignition plugs and the other distributing part or parts are appropriately equipped with the remaining discharge electrodes, and changeover means for changing the distribution of the secondary voltage generated in an ignition coil from one of the distributing parts to another.

According to another aspect of the present invention, the above-mentioned distributing parts are disposed in an axially offset relation with each other around a rotary shaft which is rotated in synchronism with the rotation of the engine.

According to a further aspect of the present invention, the change-over means for changing over paths through which the secondary voltage of the ignition coil is applied to each distributing part, are disposed together with the distributing parts around the rotary shaft which is rotated in synchronism with the rotation of the engine.

The present invention will be readily understood from the following description in conjunction with the accompanying drawings in which: Fig. 1 is a circuit diagram of an embodiment of a distributor for 6-cylinder internal combustion engines according to the present invention; Fig. 2 is a circuit diagram showing an operational state of the embodiment shown in Fig.

1; Fig. 3 is a sectional view of the distributor of Fig. 1 which is mounted on a part of an engine; Fig. 4 is a circuit diagram showing another embodiment of a distributor which is suitable for use in 8-cylinder internal combustion engines, according to the present invention; and Fig. 5 is a circuit diagram showing an operational state of the embodiment of Fig. 4.

Now, explanation will be made on preferred embodiments of the present invention by reference to the accompanying drawings.

Referring to Fig. 1 which shows a distributor for a 6-cylinder internal combustion engine according to the present invention, reference characters P, to P6 denote respective ignition plugs of the six cylinders. Further, reference numeral 1 denotes an ignition coil, 2 a battery, 3 a contact breaker, and 10 and 11 distributing parts each for distributing a secondary voltage generated in the ignition coil 1 to predetermined ignition plugs.One of the distributing parts 10 includes a fixed electrode 12, a rotator head electrode 13 which rotates while making contact with the fixed electrodes 12, and three discharge electrodes 14a, 1 4b and 1 4c which are connected through high tension wires 21 to the ignition plugs Pr, P2and P3, respectively and arranged at equal distances (1200) on the circumference of a circle with its center at the center of rotation of the rotor head electrode 13.

The other distributing part 11 includes a fixed electrode 15, a rotor head electrode 16 which rotates while making contact with the fixed electrode 15, and three discharge electrodes 14d, 1 4e and 1 4f which are connected through high tension wires 22 to the remaining ignition plugs P3, P6 and P5, respectively, and are arranged at equal distances (1200) on the circumference of a circle with its center at the center of rotation of the rotor head electrode 16. Reference numeral 1 7 indicates changeover means for changing the application of the secondary voltage generated in the ignition coil 1 from one of the distributing parts 10 and 11 to the other one.The change-over means 17 includes a fixed electrode 18 connected through a high tension wire 23 to the ignition coil 1, a moval electrode 19 which rotates while making contact with the fixed electrode 18 and has three electrode heads 19a, 19b and 1 9c arranged at equal angular intervals of 120 degrees, and two discharge electrodes 20a and 20b which are connected through high tension wires 24 and 25 to the fixed electrode 12 of the distributing part 10 and the fixed electrode 1 5 of the distributing part 11, respectively, and are diametrically arranged on the circumference of a circle with its center at the center of rotation of the movable electrode 19.In the distributing parts 10 and 11 and change-over means 17, the rotor head electrodes 13 and 16 and movable electrode 1 9 are rotated counterclockwise (as indicated by arrows in synchronism with one another while maintaining such a positional relation thereamong as shown in Fig. 1, in more detail, in such a positional relation that when the rotor head electrode 13 faces the discharge electrode 14a, the rotor head electrode 16 is directed to an intermediate point between the discharge electrodes 1 4d and 1 4f (that is, makes an angle of 60 degrees with the direction of the rotor head electrode 13) and the electrode head 1 9a faces the discharge electrode 20a.

Having such a construction as described above, in such a state as shown in Fig. 1 wherein the rotor head electrode 1 3 faces the discharge electrode 14a in the distributing part 10 and the electrode head 1 9a of the movable electrode 1 9 faces the discharge electrode 20a in the changeover means 17, the distributor according to the invention operates in such a manner that when the contact breaker 3 is made open to generate the secondary voltage in the ignition coil 1 , the secondary voltage is applied to the ignition plug P, through the path consisting of the high tension wire 23-the fixed electrode 1 8 of the changeover means 17-the electrode head 1 9a of the movable electrode 1 9-the discharge electrode 20a-the high tension wire 24-the fixed electrode 12 of the distributing part 1 0-the rotor head electrode 13-the discharge electrode 14the high tension wire 21 , to ignite the airfuel mixture within the cylinder provided with the ignition plug P. After the ignition at the ignition plug P1 is completed, the rotor head electrodes 1 3 and 1 6 of the distributing parts 10 and 11 as well as the movable electrode 19 of the change-over means 1 7 are rotated counterclockwise in synchronism with one another by an angle of 60 degrees, and are put in the state shown In Fig. 2.

That is, the rotor head electrode 1 6 faces the discharge electrode 1 4f in the distributing part 11, and the electrode head 1 9c of the movable electrode 1 9 faces the discharge electrode 20b in the change-over means 1 7.Accordingly, the secondary voltage generated in the ignition coil 1 is applied to the ignition plug P5 through the path consisting of the high tension wire 23-the fixed electrode 18 of the change-over means 17-the electrode head 1 9c of the movable electrode 19-the discharge electrode 20b-- the high tension wire 25-the fixed electrode 15 of the distributing part 11-the rotor head electrode 1 6-the discharge electrode 1 4f -the high tension wire 22, to ignite the air-fuel mixture within the cylinder provided with the ignition plug s Thus, the distributing part 10 and 11 are alternately placed in the operating state every time the rotor head electrodes 13 and 1 6 and the movable electrode 1 9 rotate for 60 degrees, and the same distribution of electricity as in conventiona I distributors can be conducted.

In the distributor according to the present invention which conducts the distribution of electricity in such a manner as mentioned above, when the ignition time is varied by means of an electronic control system, the position of the rotor head electrode at a varied ignition time is deviated, as in conventional distributors, from the position where the rotor head electrode faces one of the discharge electrodes. However, since the distributor according to the present invention includes two distributing parts each having three discharge electrodes disposed at equal distances and connected respectively to the corresponding ignition plugs, the discharge length between the rotor head electrode and the adjacent discharge electrode, for example the discharge distance A plus B in Fig. 1, may be enlarged in comparison with the case of the conventional distributors.

Thus, the wrong distribution may be prevented from occurring. Further, according to the present invention, the rotor head electrodes 1 3 and 1 6 of the distributing parts 10 and 11 as well as the movable electrode 19 of the change-over means 17 may be mounted on a common rotary shaft, so that the distributor may be disposed within a space for containing therein a conventional distributor and moreover may have an advantage that the wrong distribution can be prevented from occurring even if each distributing part is made smaller in size than the conventional distributor.

Referring to Fig. 3, explanation wiii be now made on the concrete structure wherein the distributor according to the present invention is mounted on a conventional engine. In Fig. 3, reference character S denotes a rotary shaft extending out of the engine side and C a cap mounted on a housing H.On the cap C, there are provided the discharge electrodes (only the discharge electrode 1 4a is shown) and fixed electrode 1 2 of the distributing part 10, the discharge electrodes (only the discharge electrode 1 4f is shown) and fixed electrode 1 5 of the distributing part 11, and the discharge electrodes 20a and 20b and fixed electrode 18 of the change-over means 1 7. The discharge electrodes of the distributing part 10, the discharge electrodes of the distributing part 11, and the discharge electrodes of the change-over means 1 7 are arranged respectively on three concentric circles which have their center at the rotary shaft S, differ in diameter from each other, and are placed in different planes parallel to each other, namely, at different stages.Further, the fixed electrode 1 5 of the distributing part 11 is positioned on the axis of the rotary shaft S, the fixed electrode 12 of the distributing part loins disposed at a position deviated from the abovementioned axis, and the fixed electrode 1 8 of the change-over means 17 is disposed at a position which is much more deviated from the axis as compared with the fixed electrode 12. An assembly 30 for mounting the rotor head electrodes of the distributing parts and an assembly 31 for mounting the movable electrode of the change-over means are fixedly mounted on the rotary shaft S. On the surface of a cylindrical upper region of the assembly 30, there is provided the rotor head electrode 1 3 having a ring-shaped portion which is kept in contact with the fixed electrode 12. On the lower region of the assembly 30, there is provided the rotor head electrode 1 6 which is maintained in contact with the fixed electrode 1 5. Further, the movable electrode 19 having a ring-shaped portion which is maintained in contact with the fixed electrode 18, is attached to the inner surface of the assembly 31.

Incidentally, in Fig. 3, reference numeral 23 denotes a high tension wire for connecting the fixed electrode 1 8 to an ignition coil, 24 a high tension wire for connecting the discharge electrode 20a to the fixed electrode 12, 25 a high tension wire for connecting the discharge electrode 20b to the fixed electrode 15, and 21 and 22 high tension wires for connecting the discharge electrodes 1 4a and 1 4f to corresponding ignition plugs, respectively.

In the above-mentioned distributor, the secondary voltage generated in the ignition coil is transferred to the movable electrode 19 through the high tension wire 23 and the fixed electrode 18, and is applied to the discharge electrode 1 4a when the movable electrode 19 faces the discharge electrode 20a and the rotor head electrode 13 faces the discharge electrode 14a.

When the rotary shaft S is rotated by an angle of 60 degrees so that the movable electrode 18 faces the other discharge electrode 20b and the rotor head electrode 16 faces the discharge electrode 14f, the secondary voltage is applied to the discharge electrode 14f. Thus, the desired distribution of electricity is achieved.

Fig. 4 shows a distributor for an 8-cylinder internal combustion engine, as another embodimemt of the present invention. Referring to Fig. 4, one distributing part 100 includes a fixed electrode 120, a rotor head electrode 130 which is rotated while being kept in contact with the fixed electrode 120, and four discharge electrodes 140a, 140b, 140c and 140d which are connected respectively to four ignition plugs Pa, P4 P0 and P through high tension wires 210 and arranged at equal interval (90 degrees) on the circumference of a circle'with its center at the center of rotation of the rotor head electrode 130.

The other distributing part 110 includes a fixed electrode 150, a rotor head electrode 160 which is rotated while being kept in contact with the fixed electrode 150, and four discharge electrodes 1 40e, 1 40f, 1 40g and 1 40h which are connected respectively to the remaining ignition plugs Pa, P3, P5 and P2 through high tension wires 220 and arranged at equal intervals (90 degrees) on the circumference of a circle with its center at the centerof rotation of the rotor head electrode 60.

A chargesver means 170 for alternately changing the application of the secondary voltage generated in an ignition coil from one of the distributing parts 100 and 110 to the other includes a fixed electrode 180 connected through a high tension wire 230 to the ignition coil 1, a movable electrode 190 which is iotated while being kept contact with the fixed electrode 180 and has four electrodes heads 1 90a, 1 90b, 1 90c and 1 90d arranged at equal angular intervals of 90 degrees, and two discharge electrodes 200a and 200b which are connected through high tension wires 240 and 250 to the fixed electrode 120 of the distributing part 100 and the fixed electrode 150 of the distributing part 110, respectively, and are arranged on the circumference of a circle with its center at the center of rotation of the movable electrode 1 90. Further, the discharge electrodes 200a and 200b are disposed in such a positional relation that the line connecting the discharge electrode 200a with the center of rotation of the movable electrode 190 makes an angle of 45 degrees with the line connecting the discharge electrode 200b with the above-mentioned center of rotation. In the distributing parts 100 and 101 and the change-over means 170, the rotor head electrodes 130 and 160 and the movable electrode 1 90 are rotated clockwise as indicated by arrows in synchronism with one another while maintaining the positional relation there among as shown in Fig. 4.That is, when the rotor head electrode 130 faces the discharge electrode 140a, the rotor head electrode 1 60 is directed to an intermediate position between the discharge electrodes 1 40e and 140h, and the movable electrode 1 90 is put in such a state that the electrode head 1 90 faces the discharge electrode 200a. Incidentally, reference numerals 2 and 3 indicate a battery and a contact breaker, respectively, as in Fig. 1.

When the distributor is in the state shown in Fig. 4, the secondary voltage generated in the ignition coil 1 is applied to the ignition plug P, through the path consisting of the high tension wire 230-the fixed electrode 180 of the changeover means 170-the electrode head 1 90a of the movable electrode 1 90-the discharge electrode 200a-the high tension wire 240-the fixed electrode 120 of the distributing part 1 OO--the rotor head electode 1 30-the discharge electrode 1 40the high tension wire 210. After the ignition at the ignition plug P, has been completed, the rotor head electrodes 130 and 160 and the movable electrode 190 are rotated in synchronism with one another to assume a state shown in Fig. 5.In this state, the rotor head electrode 160 of the distributing part 110 faces the discharge electrode 1 40e and the electrode head 1 90b of the movable electrode 190 faces the discharge electrode 140e and the electrode means 170, so that the secondary voltage generated in the ignition coil 1 is applied to the ignition plug P8. In such a manner, the distributing parts 100 and 110 are alternately operated every time the rotor head electrodes 130 and 1 60 and the movable electrode 190 rotate for 45 degrees.

Thus, the ignition plugs are ignited in the order of P1 -t P, -, P0-+ P5 P7 P2.

Each of the distributors which have been explained hereinbefore as the embodiment of the present invention includes two distributing parts.

However, the present invention is not limited to such a construction, but distributors may be provided with three or more distributing parts at need.

For example, a distributor for 6-cylinder internal combustion engines may include three distributing parts. In this case, each distributing part includes two discharge electrodes which are arranged diameterically on the circumference of a circle, and change-over means include three discharge electrodes which are arranged on the circumference of a circle at equal intervals of 120 degrees. Further, a rotor head electrode and discharge electrodes of each distributing part are positioned in such a manner that three rotor head electrodes are successively brought into a state such as facing one of discharge electrodes every time these rotor head electrodes rotate for 60 degrees, and the movable electrode of the change-over means includes two electrode heads arranged at equal intervals of 180 degrees.This construction may show the same effect as that obtained in the aforementioned embodiment of the invention.

As an alternative, another distributor for an 8cylinder internal combustion engine will be explained below which includes four distributing parts and a change-over means. In this case, each distributing part includes two discharge electrodes which are arranged diametrically on the circumference of a circle, and the change-over means includes four discharge electrodes which are arranged on the circumference of a circle at equal intervals of 90 degrees.Further, the rotor head electrode and the discharge electrodes of each distributing part are positioned in such a manner that the respective four rotor head electrodes are successively brought in a state such as facing one of discharge electrodes every time these rotor head electrodes rotate for 45 degrees, and the movable electrode of the change-over means includes two electrode heads arranged at irregular intervals of 135 degrees and 225 degrees therebetween. Such a construction as mentioned above may produce the same effect as that shown in the embodiment of Figs. 4 and 5.

As has been explained hereinbefore, a distributor according to the present invention includes a plurality of distributing parts, allots a part of discharge electrodes connected to ignition plugs to one of the distributing parts, allots the remaining discharge electrodes to one or more different distributing parts, and includes changeover means for changing the application path of the secondary voltage of an ignition coil from one of the distributing parts to another distributing part, in order to increase a spacing between adjacent discharge electrodes of each distributing part, with an advantage that the wrong distribution of electricity may be surely prevented from occuring. Further, the increase in the spacing between adjacent discharge electrodes may make wider the control range of ignition time which is conducted by means of an ignition time control system. Furthermore, although the spacing between adjacent discharge electrodes is increased, it is not required to increase the diameter of the distributor. That is, the dead space of the distributor may be made small, and therefore the distributor may be readily disposed in an engine room.

Claims (10)

1. A distributor for a multiple cylinder internal combustion engine comprising: a plurality of distributing parts for distributing a secondary voltage generated in an ignition coil to ignition plugs sequentially in a predetermined order; a rotor head electrode provided in each of said distributing parts and fixed on a rotary shaft which is rotated in synchronism with the rotation of the engine; a plurality of discharge electrodes provided in each of said distributing parts and arranged on the circumference of a circle at equal intervals with the center of said circle being placed at the center of rotation of said rotor head electrode;; distributing paths, formed in each of said distributing parts, from said rotor head electrode through said plurality of discharge electrodes to said ignition plugs respectively associated to said discharge electrodes, said distributing paths being successively formed one by one in response to an approach of said rotor head electrode to said respective discharge electrodes, said approach occurring sequentially with respect to said discharge electrodes in each of said discharging paths every time said rotary shaft rotates by a predetermined angle; and change-over means for changing over transmission paths for distributing said secondary voltage generated in said ignition coil to the respective rotor head electrodes of said plurality of distributing parts in accordance with an order in which said distributing paths are formed, so as to distribute said secondary voltage through said distributing paths to said ignition plugs sequentially in said predetermined order.

2. A distributor according to claim 1, wherein said change-over means includes a movable electrode electrically connected to said ignition coil and fixed on said rotary shaft and a plurality of discharge electrodes arranged on the circumference of a circle with its center at the center of rotation of said movable electrode and electrically connected to said rotor head electrodes of said distributing parts, respectively.

3. A distributor according to claim 2, wherein said distributing paths are successively formed in said distributing parts every time said rotary shaft is rotated by an angle obtained by dividing an angle of 360 degrees by the number of the cylinders, wherein said discharge electrodes of said change-over means are selected in number to be equal to said distributing parts, wherein said movable electrodes of said changeover means is provided with electrode heads the number of which is equal to a number obtained by dividing the number of cylinders by the number of distributing parts, and wherein during a period when said rotary shaft having said movable electrode fixed thereto makes a turn, one of said discharge electrodes of said changeover means successively approaches one of said electrode heads in a predetermined order to distribute said secondary voltage of said ignition coil in a predetermined order to said distributing paths formed in said distributing parts.

4. A distributor according to claim 3, wherein the cylinders, said distributing parts, and said electrode heads of said change-over means are selected in number to be six, two, and three respectively, and wherein said electrode heads are formed at equal angular intervals of 120 degrees.

5. A distributor according to claim 3, wherein the cylinders, said distributing parts, and said electrode heads of said change-over means are selected in number to be eight, two, and four, respectively, and wherein said electrode heads are formed at equal angular intervals of 90 degrees.

6. A distributor according to claim 1, wherein respective rotor head electrodes of said distributing parts and said movable electrode of said change-over means are fixed respectively at different stages to said rotary shaft, and wherein said discharge electrodes facing each of said rotor head electrodes and said movable electrode are fixed on a cap enclosing said rotary shaft.

7. A distributor for a multiple cylinder internal combustion engine comprising: a plurality of distributing parts for distributing a secondary voltage generated in an ignition coil to ignition plugs sequentially in a predetermined order, one of said distributing parts being provided with a part of electrodes connected respectively to said ignition plugs, the remainder of said electrodes being allotted to the remainder of said distributing parts; and changeover means supplied from said ignition coil with said secondary voltage for changing the distribution of said secondary voltage over a path to one of said distributing parts to a path to another of said distributing parts.

8. A distributor for a multiple cylinder internal combustion engine, wherein a plurality of rotor head electrodes are fixed on a rotary shaft rotated in synchronism with the rotation of the engine, a plurality of discharge electrodes being disposed around each of said rotor head electrodes at equal intervals and connected respectively correspondingly to ignition plugs, said discharge electrodes being equal in number to each other for each of said rotor head electrodes, each of said rotor head electrode and said discharge electrodes disposed therearound making up a distributing part, wherein every time said rotary shaft is rotated by a predetermined angle, said rotor head electrode approaches sequentially one by one of said discharge electrodes in each of said distributing parts to form distributing paths to ignition plugs sequentially in a predetermined order, and wherein change-over means are provided which changes the distribution of a secondary voltage generated in an ignition coil over a path to one of said distributing parts to another path to another of said distributing-parts.

9. A distributor for a multiple cylinder internal combustion engine comprising: a plurality of distributing parts for distributing a secondary voltage generated in an ignition coil to ignition plugs sequentially in a predetermined order, one of said distributing parts being provided with a part of electrodes connected correspondingly respectively to said ignition plugs, the remainder of said electrodes being allotted to the remainder of said distributing parts; and change-over means including a movable electrode fixed on a rotary shaft and a plurality of discharge electrodes disposed on the circumference of a circle with its center at the center of rotation of said movable electrode to distribute said secondary voltage generated in said ignition coil to said rotor head electrode of each of said distributing parts through said movable electrode and one of said discharge electrodes of said change-over means, said rotary shaft being rotated in synchronism with the rotation of the engine, said discharge electrodes of said changeover means being selected to be equal in number to said distributing parts.

10. A distributor substantially as hereinbefore described with reference to Figs. 1,2 and 3 or Figs. 4 and 5 of the accompanying drawings.