JPS6172878A - Ignition signal generator for internal-combustion engine - Google Patents

Abstract

PURPOSE:To secure a proper pulse signal all the time as well as to make accurate ignition timing controllable, by setting up a lot of concave and convex parts in a crankshaft at regular intervals, while securing the pulse signal which controls the ignition timing with a pulse pickup installed face-to-face to these concave and convex parts. CONSTITUTION:A crank gear 14 is formed in a crank wave installed in a crankshaft 5 being rotatably supported on a crankcase 1 via a bearing, while a clutch gear (unillustrated herein), transmitting turning force to a clutch mechanism, is engaged with the said gear 14. A pulse pickup 18 is installed in a position opposed to a lot of concave and convex parts comprising teeth 14a of the crank gear 14 at the specified interval, and fitted in a through hole 19 of the crankcase 1 and locked therein. Then, a pulse signal is generated by a voltage variation at a time when the said concave and convex parts pass through a pole piece 18b of the pickup 18, and according to this pulse signal, ignition timing control over an ignitor 21 is made to be done via an electronic ignition timing control unit 20.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an ignition signal generation device for an internal combustion engine, specifically an ignition signal generation device for an internal combustion engine that obtains a pulse signal input from a pulse pickup to an electronic ignition timing control device. It is related to.

(Prior Art) Conventionally, in non-contact type or capacitor discharge type ignition devices, there is a technique disclosed in Japanese Patent Application Laid-Open No. 59-5745, which the applicant previously filed.
As disclosed in Specification No. 8, a pickup for detecting ignition timing is provided in the crankcase, a protrusion is provided on the crankshaft facing the pickup, and when the protrusion passes through the pickup, an AC pulse is applied to the pickup. occurs and, for example, when the AC pulse is in the positive direction, a high voltage is generated in the ignition coil.

Incidentally, in recent years, ignition systems have been equipped with electronic ignition timing control devices that determine ignition timing from the engine speed, intake pipe pressure, warm-up, and other operating conditions.

An ignition signal generator for an internal combustion engine equipped with this type of ignition device, for example, forms a large number of equally spaced protrusions on the rotating body of a power generator, and generates a pulse signal from a pulse pickup placed opposite the protrusions. It has gained.

(Problems to be Solved by the Invention) As described above, in an ignition system equipped with an electronic ignition timing control device, the optimum ignition timing for the operating condition is determined based on the input pulse signal. Or the ignition is delayed. For this reason, the pulse signal input to the ignition device must be such that the operating state can be accurately determined.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide an ignition signal generating device for an internal combustion engine that obtains a pulse signal by rotating a crankshaft and is optimal for electronic ignition timing control.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides irregularly spaced parts on the circumference of the crankshaft rotatably supported by the crankcase. The present invention is characterized in that a large number of concave and convex portions are formed, and a pulse pickup is provided at a position facing the concave and convex portions, and a pulse signal input to an electronic ignition timing control device is obtained by this pulse pickup.

(Function) In the present invention, as the crankshaft rotates, a large number of concavo-convex portions arranged on the circumference -L of the crankshaft pass through a pulse pickup provided opposite to the concavo-convex portions. At this time, the pulse pickup can obtain a pulse signal with a frequency proportional to the rotational speed due to the unevenness of the crankshaft, and this pulse signal is input to the electronic ignition timing control device and changes depending on the operating state of the internal combustion engine. control to advance or retard the angle.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a plan view showing a crank case of an internal combustion engine with an upper case removed, and FIG. 2 is a side view showing the arrangement of a pulse pickup and a crank gear.

In the figure, reference numeral 1 denotes a crankcase, and this crankcase 1 is constructed by joining and fixing an upper case 2 and a lower case 3. Bearing walls 4 are arranged at predetermined intervals inside the crankcase l, and the crankshaft 5 is connected to the crankcase l.
It is rotatably supported by the side wall 1a and the bearing wall 4 via a bearing 6. This bearing 6 adopts a split type in which two semicircular plate-shaped metal pieces are fitted together.

The crank webs 7 provided on the crankshaft 5 are arranged in crank chambers partitioned by the respective bearing walls 4, and the crank pins 8 formed between the crank webs 7 are connected by connecting rods 9 (not shown). connected to the piston.

Therefore, the linear motion caused by the -L downward movement of the piston is converted into a rotational motion via the connecting rod 9, which rotates the crankshaft 5.

The crankshaft 5 is provided with a gear 11 that is connected to a starter motor (not shown) by a chain lO. Further, a gear 12 is provided near this gear 11, and a chain 1
3, it is connected to a camshaft (not shown) that opens and closes intake and exhaust valves.

A crank gear 14 of the crankshaft 5 is formed on the crank web 7, and this crank gear 14 meshes with a clutch gear 15 to transmit the rotational force of the crankshaft 5 to a clutch mechanism 16. Teeth 14 of crank gear 14
a consists of a large number of uneven parts arranged at equal intervals, and one tooth 14b is formed with a notch 17 of a predetermined width, and this notch 17 is used to determine the top dead center or bottom dead center of the piston. It has become.

A pulse pickup 18 is provided on a side wall 2a in the crankshaft direction of the upper case 2 constituting the crankcase l. The pulse pickup 18 is the case body 18
This is a well-known device in which a magnetic pole piece tab and a coil 18c are built in. This pulse pickup 18 is disposed at a position facing the crank gear 14 so as to be integrated with the side wall 2a of the upper case 2. That is, the side wall 2 of the upper case 2
A through hole 19 is formed in the through hole 19, and the case body 18a of the pulse pickup 18 is embedded in the through hole 19, and the tip of the magnetic pole piece 18b faces the crank gear 14 at a predetermined distance.

The pulse pickup 18 is connected to the teeth 14a of the crank gear 14.
When the unevenness formed by the magnetic pole piece 18b passes through the magnetic pole piece 18b, the output voltage changes and a pulse signal corresponding to the unevenness is generated. This pulse signal is input to the electronic ignition timing control device 20, which determines the ignition timing based on the pulse signal and intake pipe pressure, etc., and sends a primary current cutoff signal to the igniter 21 to ignite the spark plug 22.

Next, the operation of this embodiment will be explained.

The vertical movement of a piston (not shown) rotates the crankshaft 5 via the connecting rod 9, and the rotational force of the crankshaft 5 is transmitted from the crank gear 14 to the clutch gear 15. As the crank gear 14 rotates, its teeth 14a pass through the magnetic pole piece 18b of the pulse pickup 18, and the output voltage from the coil 18c changes depending on the unevenness of the teeth 14a, and a pulse signal corresponding to the unevenness is output. Therefore, the crank gear 14
A pulse signal accompanying the rotation of the electronic ignition timing control device 20
Based on this pulse signal, the microcomputer provided in the electronic ignition timing control device 20 calculates the engine speed, determines the ignition timing according to the operating condition from the intake pipe pressure, etc. Sends a current cutoff signal.

FIGS. 3 to 6 show other embodiments in which the crank web of the crankshaft is provided with a large number of concave and convex portions.

In FIG. 3, a large number of equally spaced teeth 7a are integrally formed on the outer periphery of the crank web 7 of the crankshaft 5, creating an uneven part. A notch 17 is provided for positioning the dead center. This tooth 7a
The crank web 7 on which the crankshaft 5 is formed is located on the side walls 2b and 3a of the upper case 2 and the lower case 3 that pivotally support the crankshaft 5, and the pulse pickup 18 is arranged on the side wall 2a of the upper case 2 in the direction of the crankshaft. It is set up.

The pulse pickup 18 may be disposed on the side wall 2b of the case 2 that supports the crankshaft 5, or may be disposed on the same side wall of the lower case 3 as the upper case 2.

FIG. 4 shows another embodiment in which the uneven portion is not directly formed on the crank web.

An annular step 7b is formed by casting or cutting on the outer periphery of the side wall of the crank web 7 that pivotally supports the crankshaft 5. An annular member 23 is press-fitted into the stepped portion 7b, and teeth 23a are formed at equal intervals on the outer periphery of the annular member 23.

It goes without saying that the pulse pickup 18 is disposed at a position facing the teeth 23a, and may be located on either the side wall in the crankshaft direction or the side wall on the bearing side.

FIGS. 5 and 6 show another embodiment in which uneven portions are formed directly on the crank web.

The pulse pickup 18 is disposed on a side wall that pivotally supports the crankshaft 5, and five round holes 7d are bored in the side surface 7c of the crank web 7 facing the pulse pickup 18. The distance between these round holes 7d is 120 degrees at one point, and the distance at the other four points is 120 degrees.
The locations are equally spaced at 60 degrees. By changing the angle, the top dead center or bottom dead center of the piston is determined.

In the above embodiment, the pulse filter 2p 18 is arranged so as to be embedded in the side wall of the crankcase l, but it may be arranged inside or outside the crank chamber without being provided in the side wall. Furthermore, the concavo-convex portion for pulse detection may be disposed on the rotating portion of the crankshaft 5, and the concavo-convex portion for pulse detection may be provided on the rotating portion of the crankshaft 5,
4. It is not limited to the crank web 7, and may be formed on other gears or the crankshaft 5 itself.

(Effects of the Invention) As described above, this invention provides a crankshaft with a large number of concave and convex portions arranged at equal intervals, a pulse picker 2 that is located opposite the concave and convex portions, and a pulse pick-up that controls the ignition timing. Since the control pulse signal is obtained, it is possible to obtain the optimal pulse signal for electronic ignition timing control based on the rotation of the crankshaft, making it possible to accurately control the ignition timing.

[Brief explanation of the drawing]

Figure 1 is a plan view showing the internal combustion engine with the upper case of the crank case removed, Figure 2 is a sectional view showing the arrangement of the pulse pickup and crank gear, and Figure 3 is a large number of FIG. 4 is a diagram showing another embodiment in which uneven portions are formed at equal intervals on the crank web. FIGS. 5 and 6 are illustrations in which uneven portions are formed directly on the crank web. FIG. 5 is a front view, and FIG. 6 is a side view. l...Crank case 2...Upper case 2a, 2
b...Side wall 3...Lower case 5...Crankshaft 7-...Crank web 7a...Teeth
7b...Stepped portion 7C...Side surface 7d...
Round hole 14... Crank gear 14a... Teeth 17.
... Notch 18 ... Pulse pickup 20 ... Electronic ignition timing control device 23 ... Annular member 23a ... Teeth jI3 diagram

Claims (1)

[Claims] On the circumference of the crankshaft, which is rotatably supported by the crankcase, a number of irregularities with irregular parts are formed at equal intervals, and a pulse pickup is provided at a position facing the irregularities. , an ignition signal generation device for an internal combustion engine that uses this pulse pickup to obtain a pulse signal that is input to an electronic ignition timing control device.