JP2887512B2 - Ignition control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition control device, and more particularly to an ignition control device suitable for a multi-cylinder engine in which two spark plugs are provided in the same cylinder. .

(Background technology)

Conventionally, as shown in FIG. 7, a so-called double-plug engine in which two spark plugs 52 are provided in the same cylinder 50 has been devised. In this double plug system, the ignition plugs 52, 52 are generally arranged almost symmetrically with respect to the center of the combustion chamber 60 as shown in the figure, and each ignition plug is arranged at a position deviated from the center. is there. In FIG. 7, reference numeral 61 denotes a piston.

Such a double-plug system is devised to achieve complete combustion of the air-fuel mixture in the combustion chamber. In general, the combustion propagation distance covered by one ignition plug is reduced, and the combustion time is shortened. And advantageous,
It is used relatively frequently in engines with large heat loads, such as large outboard motors.

FIG. 8 shows an example of a general connection between the ignition coil and the ignition plug in the double-plug type six-cylinder two-stroke engine. In FIG. 8, two ignition plugs 52, 52 connected to both ends of a two-pole simultaneous ignition coil 51 are connected in each cylinder 50. In this case, the two spark plugs 5 arranged in each cylinder 50
2,52 are configured to be ignited simultaneously. For this reason,
When the stability of combustion is most important at low load and low speed, especially in the case of a two-stroke engine, irregular combustion originally occurs, so it is necessary to stabilize combustion by greatly retarding the combustion. there were. That is, by retarding the combustion, the combustion speed is reduced, the explosion pressure is reduced, and the difference between when ignition is not performed and when ignition is reduced, thereby stabilizing combustion.

[Problems to be solved by the invention]

As described above, the conventional double plug system is suitable for preventing abnormal combustion such as knocking because the combustion time is short, but on the other hand, the single plug system is required to ensure the stability of combustion. It was necessary to provide a larger retardation width as compared with. However, depending on the advance mechanism, the setting of the advance-retard width of the ignition timing is limited,
In such a case, it is difficult to perform the ignition timing control as required, and there is a disadvantage that irregular combustion at low speed cannot be prevented.

〔The invention's effect〕

SUMMARY OF THE INVENTION An object of the present invention is to provide an ignition control device which can solve the disadvantages of the conventional example, can prevent abnormal combustion such as knocking at high speed, and can also prevent irregular combustion at low speed.

[Means for solving the problem]

The present invention provides an ignition timing signal output means for outputting an ignition timing signal, two ignition plugs connected to at least two two-pole simultaneous ignition coils, and an output signal from the ignition timing signal output means. And a control unit that determines the ignition timing of each of the ignition plugs according to the throttle opening and the crank angle and controls the ignition timing.
Among them, two spark plugs connected to each two-pole simultaneous ignition coil are respectively arranged in different cylinders and in each cylinder. Then, the control unit sets the ignition mode of the ignition plug in the same cylinder to the double ignition mode when the engine speed is equal to or higher than the first set speed, and to set the engine speed to be equal to or less than the second set speed. In such a case, an ignition mode switching function for setting the ignition mode to the single ignition mode is adopted. This aims to achieve the above-mentioned object.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 6.

Here, the same reference numerals are used for components equivalent to those of the above-described conventional example. In addition, this embodiment has 6
This is for a two-cylinder engine.

In this embodiment, as shown in FIG. 1, pickup coils 2A, 2B, and 2C as three ignition timing signal output means for detecting the rotation of the magneto rotor 1 at intervals of 60 ° and outputting ignition timing signals respectively. And 6 of No.1 to No.6
One of the two spark plugs 52a connected to two pole simultaneous ignition coil _{51 1 ~51 6, 52b, 52c} , 52d, 52e, 52f, 52g, 52h, 52i,
52j, 52k, 52l and the output signals of the pickup coils 2A to 2C, determine the ignition timing of the ignition plugs 52a to 52l according to the throttle opening and the crank angle, and control the ignition timing as a control unit for controlling the ignition timing. And a control unit 10.

This ignition timing control unit 10 is a so-called CDI
The ignition type is used, and the magneto rotor 1
The ignition capacitor C _1, C ₂ that is charged by the AC electromotive force generated in the capacitor charging coil 3 by the rotation of the six thyristors SCR ₁ ~SCR for controlling the discharge of the ignition capacitor C _1, C _{2 6} and these thyristors SCR _{1 to} SCR ₆
Signal distribution circuit 4 that outputs a trigger pulse to the gate of
And an advancing operation circuit 5 for outputting a signal to the signal distribution circuit 4 for each ignition timing determined as described later, and outputting various signals to be described later to the advancing operation circuit 5 for determining the ignition timing. And the like.

The pickup signal processing circuit 6 is connected to the three pickup coils 2A to 2C, the gear count coil 7, and the throttle sensor 8 described above.

The gear count coil 7 generates a pulse in accordance with the unevenness of the teeth of a ring gear (not shown) provided integrally with the rotor 1 of the magneto. The number of pulses per rotation of the rotor from the gear count coil 7 is determined by the number of teeth of the entire ring gear. Therefore, by counting the output pulses of the gear count coil 7 using the output of the pickup coil as a start signal, it is possible to know the change in the crank angle. The throttle sensor 8 outputs a voltage signal proportional to the throttle opening of a carburetor (not shown).

Upon receiving the ignition timing signals from the pickup coils 2A to 2C, the pickup signal processing circuit 6 counts a predetermined number of pulses of the gear count coil 7 determined according to the throttle opening, and outputs an ignition signal after the count is completed. Further, in the present embodiment, in the pickup signal processing circuit 6, any one pickup coil, for example,
By performing frequency-voltage conversion on the output of 2A, a signal corresponding to the engine speed is output.

The lead angle calculation circuit 5 determines the ignition timing of the ignition plugs 52a to 52l based on these various signals from the pickup signal processing circuit 6, and outputs this signal to the signal distribution circuit 4. The signal distribution circuit 4 distributes this signal, outputs a trigger pulse to each thyristor SCR, and turns on each thyristor SCR. As a result, the ignition capacitors C ₁ and C ₂
Is discharged instantaneously, a current flows to the primary side of the two-pole simultaneous ignition coil 51, a high voltage is generated on the secondary side, and connected to the secondary side of the two-pole simultaneous ignition coil 51. 2
Book spark plugs 52a, 52b (52c, 52d: 52e, 52f: 52g, 52h: 52
i, 52j: 52k, 52l) and sparks fly at the same time.

Here, in the present embodiment, as shown in FIG. 2, the spark plugs connected to the secondary side of each two-pole simultaneous ignition coil are arranged in cylinders that are 180 ° out of phase with each other. That is, the spark plugs 52a, 52 g in No.1 cylinder 50 _1, the spark plug 52c, 52i is the No.2 cylinder 50 _2, the spark plug 52e, 52
k is the No.3 cylinder 50 _3, the spark plug 52 b, 52h for No.4 cylinder 50 _4, the spark plug 52 d, 52j are No.5 cylinder 50 ₅
Within, the spark plug 52f, 52l to No.6 cylinder 50 _6, are disposed respectively. In this embodiment, the advance calculation circuit 5 of the ignition timing control unit switches the ignition mode as shown in the flowchart of FIG. 4 according to the engine speed. That is, in the advance angle calculation circuit 5, when the engine is started, first, the single ignition mode is set (step S101), and the current engine speed N (rpm) is compared with the first set speed N ₁ (rpm). (S102). Then, while the N <N ₁ is established to sustain the setting of the single ignition mode, N ≧ engine speed rises
Becomes the N ₁ is set to double ignition mode (S103). And, in turn, performs a comparison of the current engine speed N (rpm) and the second set rotation speed N ₂ (S104). And N> N ₂
There maintaining the configuration of the double ignition mode during the hold, the engine speed returns to the start becomes a N ≦ N ₂ decreases,
Set to single ignition mode again. The relationship between N ₁ and N ₂ is assumed to be determined such that N _1> N _2. Then, the hysteresis portions N _{1 to} N ₂ as shown in FIG.
Is provided, and self-excitation at the boundary can be avoided.

FIG. 5 shows a state in each cylinder in the double ignition mode in this embodiment.

Here, when attention is paid to the No.1 cylinder 50 _1, TDC (top dead center: TOP DEAD CENTER) immediately before the coil 51 _1, 51 ₄ side into two which are respectively connected the spark plug 52a, the 52g By igniting at the same time, rapid combustion occurs and knock resistance is improved. From this point, if the 180 ° crankshaft rotation, turn sparks generated for combusting No.4 cylinder 50 ₄ flies even No.1 cylinder 50 _1, but No.1 cylinder 50 ₁ This nowadays dead center (BDC) Before, that is, in the scavenging step, combustion is not generated because no air is supplied around the spark plug, and wasteful fire occurs.

Further 180 ° crankshaft rotates, the first as well as two spark plugs 52a, 52 g ignites by the action of the coil 51 _1, 51 _4, combustion occurs. Thereafter, No. 1 cylinder 50 ₁
Within, the same operation is repeated. No. 2 to No. 6
The same process is repeated for the cylinder with each phase difference.

FIG. 6 shows a state in the single ignition mode in this embodiment.

In the action of the coil 51 ₁ near top dead center of No.1 cylinder 50 _1,
No.1 cylinder 50 ₁ and No.4 cylinders 50 ₄ sparks fly, but
No.4 cylinder 50 ₄ is wasted fire. In No.1 cylinder 50 _1, 2 is the spark plugs 52a, of 52 g, 52a only fly sparks, because the spark plug 52a is positioned biased to the center of the normal as well as the combustion chamber, Relatively slow burning occurs. This slowness reduces the explosion (combustion) pressure and ensures combustion stability (prevents irregular combustion).

From this point, when the crank rotates 180 °, in order to burn the No.4 cylinder 50 _4, No.1 cylinder 50 ₁ and No.4
Cylinder 50 ₄ sparks fly, but because in the No.1 cylinder is near the bottom dead center, it does not lead to combustion. Further is 180 ° crank rotates, the coil 51 _4, No.1 cylinder 50 ₁
And No.4 cylinders 50 ₄ to jump sparks, No.1 in the cylinder 50 within _1, slow combustion starts from the spark plug 50g towards the spark is not fly in the previous cycle. Hereinafter, similarly, for each cycle, the spark plug 52 by the action of the coil 51 _1, 51 ₄
a, 52g is ignited alternately. In addition, the same process is repeated with the respective phase differences in No. 2 to No. 6 cylinders. Thus, for each cycle, the No. 1 to No. 3 coils 51
_1, 51 _2, 51 ₃ and No.4~No.6 coil 51 _4, 51 _5, 51 by exerting ₆ alternately, 2 arranged in the same cylinder
Since the ignition plugs are alternately ignited, in the present embodiment, the temperature of any of the ignition plugs does not drop too much, the engine speed increases, and when the double ignition mode is set again, the ignition of the plugs is stopped. Trouble such as misfire due to temperature drop can be prevented.

As described above, according to the present embodiment, the ignition mode switching function of the ignition timing control unit 10 causes one of the combustion chambers to be biased with respect to the center of the combustion chamber at low engine speed, that is, at low speed. Since the ignition plug is ignited, the combustion time is prolonged and the combustion stability is ensured.
Irregular combustion can be prevented. On the other hand, when the engine is running at high speed, that is, at high speed, two ignition plugs in the same cylinder are ignited at the same time, so that rapid combustion occurs (complete combustion of the air-fuel mixture is ensured) and knocking etc. Abnormal combustion can be prevented. Further, since the portion between N _{1 and} N ₂ rpm forms a hysteresis portion as shown in FIG. 3, the self-excitation phenomenon at the boundary portion is avoided. Furthermore, since two plugs in the same cylinder are used alternately in the single ignition mode at low speed,
Troubles such as misfire can be effectively prevented.

Further, according to the present embodiment, each two-pole simultaneous ignition coil is operated twice in one cycle to burn each cylinder (air-fuel mixture therein) at a rate of one rotation of the crankshaft. Therefore, there is no need to increase the number of components in comparison with the normal double plug method, and an increase in cost can be prevented.

In the above-described embodiment, the ignition is alternately performed in the single ignition mode without giving characteristics to the positions of the two spark plugs in the same cylinder. However, the combustion state at low speed is determined by the positional relationship between the scavenging port and the exhaust port. It is also possible to use only one of the spark plugs in order to further ensure the above. Further, in the above embodiment, a six-cylinder two-stroke engine has been described as an example. However, the present invention is not limited to this. The present invention is applicable to any engine having two or more cylinders, and is applicable to a four-stroke engine. is there.

〔The invention's effect〕

Since the present invention is configured and functions as described above, according to this, each of the two spark plugs connected to the secondary side of each of the two-pole simultaneous ignition coils is placed in a different cylinder and in each of the cylinders. Since each of the two ignition coils is arranged in the same cylinder, one or two ignition coils are simultaneously operated to simultaneously ignite both ignition modes of two ignition plugs in the same cylinder. It is possible to easily switch the single ignition mode in which only the ignition is performed, and it is possible to prevent an increase in cost because there is no need to provide any new parts with respect to the normal double plug system. When the engine is running at a low speed, one of the ignition plugs located at a position deviated from the center of the combustion chamber is ignited. The time becomes longer, combustion stability is secured, irregular combustion can be prevented, and when the engine is running at high speed, two ignition plugs in the same cylinder are ignited at the same time, causing rapid combustion and abnormal combustion such as knocking. It is possible to provide an excellent ignition control device which can prevent the occurrence of the ignition.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the overall circuit configuration of an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the connection between the ignition coil and the ignition plug and the arrangement of the ignition plug in the cylinder in the above embodiment. 3 is a diagram showing the switching of the ignition mode in the above embodiment, FIG. 4 is a flowchart showing the ignition mode switching control operation of the ignition timing control unit in FIG. 1, and FIG. FIG. 6 is an explanatory view showing a combustion state in each cylinder of FIG. 6, FIG. 6 is an explanatory view showing a combustion state in each cylinder in the single ignition mode, FIG.
FIG. 8 is an explanatory view showing the arrangement of a spark plug in a cylinder in a normal double plug type engine, and FIG. 8 is an explanatory view showing the connection between a conventional ignition coil and an ignition plug and the arrangement of the ignition plug in the cylinder. . 2A-2C ...... pickup coil as an ignition timing signal output unit, 10 ...... ignition timing control unit as a control unit, 50 _{1-50 6-......} cylinder 51 _{1-51 6} ...... 2-pole simultaneous ignition coil, 52a ~ 52l …… Spark plug.

Claims (1)

(57) [Claims] An ignition timing signal output means for outputting an ignition timing signal; two spark plugs connected to the secondary sides of a plurality of two-pole simultaneous ignition coils; and an output from the ignition timing signal output means. A control unit that receives a signal, determines the ignition timing of each of the ignition plugs according to the throttle opening and the crank angle, and controls the ignition timing. Two spark plugs connected to the same side are respectively arranged in different cylinders and in each of the cylinders, and the control unit sets the ignition mode of the spark plugs in the same cylinder to engine rotation. When the engine speed is equal to or higher than the first set speed, the engine is set to the double ignition mode. When the engine speed is equal to or lower than the second set speed, the engine is set to the single ignition mode. Ignition control apparatus, characterized in that it has an ignition mode switching function of.