JPH051657A - Ignition signal generating device for internal combustion engine - Google Patents

Abstract

PURPOSE:To accurately control ignition timing by providing a pulse pick-up for a position faced to a recessed and projected section so that pulse signals controlling ignition timing can be obtained, and thereby obtaining pulse signals optimum for electronic ignition timing control with a crank shaft rotated. CONSTITUTION:A pulse pick-up 20 allows output voltage to be changed when the recessed and projected section of a circular member 18 passes through a magnetic pole piece 20b, so that pulse signals are generated in response to the recessed and projected section of the member. The pulse signals are inputted into an electronic ignition timing control device 22, ignition timing is then determined on the basis of the pulse signals, the pressure of an intake air pipe and the like, and the cut-off signal of primary current is sent to an ignitor 23 so that a spark plug 24 is thereby ignited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition signal generator for an internal combustion engine, and more particularly to an ignition signal generator for an internal combustion engine which obtains a pulse signal input from a pulse pickup to an electronic ignition timing control device. is there.

[0002]

2. Description of the Related Art Conventionally, in a non-contact type or a capacitor charging type ignition device, as disclosed in Japanese Patent Application Laid-Open No. 59-574558 previously filed by the applicant,
An ignition timing detection pickup is provided on the crankcase, and a protrusion is provided on the crankshaft so as to face the pickup. When the protrusion passes through the pickup, an AC pulse is generated in the pickup, for example, when the AC pulse is in the positive direction. The high voltage was generated in the ignition coil.

By the way, in recent years, some ignition devices are equipped with an electronic ignition timing control device for determining the ignition timing from the operating state of the internal combustion engine, the intake pipe pressure, the warm-up and the like. In an ignition signal generator for an internal combustion engine equipped with this kind of ignition device, for example, a large number of protrusions at equal intervals are formed on a rotating body of a power generator, and a pulse signal is output from a pulse pickup arranged facing the protrusions. It has gained.

[0004]

As described above, in the ignition device provided with the electronic ignition timing control device, the optimum ignition timing for the operating condition is judged based on the input pulse signal, that is, the advance angle or It is designed to lag and ignite. Therefore, the pulse signal input to the ignition device must be such that the operating state can be accurately determined.

The present invention has been made in view of such circumstances, and an object thereof is to obtain a pulse signal by rotation of a crankshaft and generate an ignition signal of an internal combustion engine most suitable for electronic ignition timing control. It is intended to provide a device.

[0006]

In order to achieve the above object, an ignition signal generator for an internal combustion engine according to the present invention rotatably supports a crankshaft in a crankcase, and the crankshaft end portion of the crankshaft is supported. An annular step is formed on the crankshaft adjacent to the vicinity of the bearing, and an annular member is fitted to the step,
A large number of irregular portions having irregular portions are formed on the outer periphery of the annular member at equal intervals, and a pulse pickup is provided on the crankcase wall at a position facing the irregular portions, and an electronic ignition timing is provided by the pulse pickup. The palace signal input to the control device is obtained.

[0007]

Since the ignition signal generating device for the internal combustion engine is constructed as described above, a large number of concavo-convex portions of the annular member fitted to the crankshaft by the rotation of the crankshaft are provided facing the concavo-convex portions. Passed the pulse pickup. At this time, the pulse pickup can obtain a palace signal having a frequency proportional to the rotation speed of the crankshaft by the concave and convex portion, and the palace signal is input to the electronic ignition timing control device and advances according to the operating state of the internal combustion engine. The control for angling or retarding is performed.

[0008]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a crankcase of an internal combustion engine according to the present invention.
FIG. 2 is a plan view showing a state in which the upper case of the shoe is removed, and FIG. 2 is a partial cross-sectional view showing an arrangement state of the pulse pickup and the annular member.

In the figure, reference numeral 1 is a crank case, and the crank case 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 crank case 1, and a crank shaft 5 is rotatably supported by a side wall 1a of the crank case 1 and the bearing wall 4 via a bearing 6. There is. The bearing 6 is of a split type in which two semi-circular plate-shaped metals are joined together.

A crank web 7 provided on the crank shaft 5 is arranged in a crank chamber defined by the respective bearing walls 4, and a crank pin 8 formed between the crank webs 7 is connected by a connecting rod 9. A linear motion due to vertical movement of a piston (not shown) is converted into a rotary motion via the connecting rod 9, and the crankshaft 5 is rotated.

The crankshaft 5 is provided with a gear 11 which is connected to a starter motor (not shown) by a chain 10. A gear 12 is provided in the vicinity of the gear 11, and is connected via a chain 13 to a cam shaft that opens and closes an intake / exhaust valve (not shown).

The crank gear 14 of the crank shaft 5 is formed on the crank web 7, and the crank gear 14 meshes with the clutch gear 15 to transmit the rotational force of the crank shaft 5 to the clutch mechanism 16.

A bearing 6a is provided at the shaft end of the crankshaft 5.
Is provided, and an annular step portion 17 is provided on the crank web 7a on the crank shaft adjacent to the bearing 6a.
The annular member 18 is fitted to the step portion 17. A large number of concave and convex portions 19 are formed on the outer periphery of the annular member 18 at equal intervals, and no convex portion is formed on a portion 19a thereof. Then, the top dead center or the bottom dead center of the piston is known at the portion 19a where the convex portion is not formed.

A pulse pickup 20 is provided on the side wall 2a of the upper case 2 constituting the crank case 1 in the crankshaft direction. This pulse pickup 20
Is a well-known case in which a pole piece 20b and a coil 20c are built in a case body 20a. The pulse pickup 20 is arranged at a position facing the uneven portion 19 of the annular member 18 so as to be integrated with the side wall 2a of the upper case 2. That is, the through hole 21 is formed in the side wall 2a of the upper case 2, and the case of the pulse pickup 20 is formed in the through hole 21.
The main body 20a is embedded, and the tip end of the magnetic pole piece 20b faces the concave-convex portion 19 of the annular member 18 with a predetermined space.

In the pulse pickup 20, when the unevenness of the annular member 18 passes through the magnetic pole piece 20b, 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 22, the ignition timing is determined from the pulse signal and the intake pipe pressure, and a primary current cutoff signal is sent to the igniter 23 to ignite the ignition plug 24.

Next, the operation of this embodiment will be described. By moving the piston (not shown) up and down, the connecting rod 9
The crankshaft 5 is rotated via the crankshaft 5, and the rotational force of the crankshaft 5 is transmitted from the crank gear 14 to the clutch gear 15. As the crankshaft 5 rotates, the irregularities of the annular member 18 pass through the magnetic pole pieces 20b of the pulse pickup 20, and the irregularities change the output from the coil 20c, so that a pulse signal corresponding to the irregularities is output.

Therefore, a pulse signal associated with the rotation of the crankshaft 5 is input to the electronic ignition timing control device 22, and the microcomputer provided in the electronic ignition timing control device 22 uses the pulse signal as a basis for the engine. The engine speed is calculated, the ignition timing according to the operating condition is determined from the intake pipe pressure, etc., and a primary current cutoff signal is sent to the igniter 23.

Although the pulse pickup 20 is normally arranged as shown by the solid line in order to make the pulse pickup 20 face the uneven portion, the pulse pickup 20 may be arranged as shown by the phantom line in FIG. .

[0019]

In the ignition signal generator for an internal combustion engine according to the present invention, a large number of concavo-convex portions are arranged at equal intervals on an annular member fitted to the crankshaft, and a pulse pickup is provided at a position facing the concavo-convex portions. Since the pulse signal for controlling the ignition timing is provided by the pulse pickup, the optimum pulse signal for the electronic ignition timing control can be obtained by the rotation of the crankshaft, and the accurate ignition timing can be controlled.

Further, since the annular member is fitted to the crankshaft, it is easy to adjust the weight balance of the left and right crank webs, and an unbalanced load is not generated due to the irregular shape of the crank webs. It can be eliminated, and speed can be increased without the need for reinforcement and supplementary lubrication.
It is possible to provide a crankshaft with excellent durability.

Further, the pulse pickup is a crankcase.
Since it is mounted on the wall of the power generator, the outer diameter of the power generator can be made compact and the width of the engine does not become larger than that of the conventional generator which has a pulse pickup mounted on the cover.

[Brief description of drawings]

FIG. 1 is a plan view showing a state in which an upper case of a crankcase of an internal combustion engine according to the present invention is removed.

FIG. 2 is a partial cross-sectional view showing an arrangement state of a pulse pickup and an annular member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crank case 2a Crank case wall 5 Crank shaft 6a Bearing 7a Crank web 17 Step section 18 Annular member 19 Concavo-convex section 19a Irregular section 20 Pulse pickup 22 Electronic ignition timing control device

Claims (1)

Claim: What is claimed is: 1. A crankshaft is rotatably supported by a crankcase, and an annular step is formed on the crankshaft adjacent to a bearing at an end of the crankshaft. An annular member is fitted to the stepped portion, a large number of irregular portions having irregular portions are formed on the outer periphery of the annular member at regular intervals, and a pulse pickup is mounted on the crankcase wall at a position facing the irregular portion. An ignition signal generator for an internal combustion engine, wherein the pulse pickup is used to obtain a palace signal input to an electronic ignition timing controller.