JP2002013459A - Ignition method and device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve startability of an engine by feeding high voltage to an ignition plug for the engine at all times. SOLUTION: This ignition device for the engine includes a cranking means for a crankshaft 18, an AC generator 24 connected to the crankshaft 18, a smoothing circuit (regulator) 27 for smoothing the output voltage of the AC generator 24, and an igniter 22 generating the ignition energy based on the output voltage of the smoothing circuit 27. The timing when the output of the smoothing circuit 27 shows the maximum value is synchronized with the ignition timing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for igniting an engine, and more particularly, to a method and apparatus for igniting an engine capable of generating a large voltage in an ignition coil even when a battery has a reduced discharge capacity. Related to the device.

[0002]

2. Description of the Related Art When starting an engine, it is necessary to supply sufficient electric power to an ignition device to supply large ignition energy to a spark plug. Therefore, when the battery discharge capacity is low, even if an attempt is made to start the engine while energizing a load such as a headlight that consumes a large amount of power, sufficient power is not supplied to the ignition device and the engine is not powered. Startability could be reduced.

To solve such a problem, Japanese Patent Laid-Open No.
No. 132877 or Utility Model Registration No. 2518
Japanese Patent Application Publication No. 904 proposes a start control device in which a lamp load such as a headlight is temporarily disconnected from a power supply line when the engine is started.

[0004]

The AC voltage generated by the generator is converted into a DC voltage by a smoothing circuit and supplied to a battery or an electric load. However, it is known that this DC voltage is not completely flat and includes a ripple synchronized with the period of the AC voltage output by the generator. Therefore, when the ignition timing comes at the valley portion of the ripple voltage, the voltage supplied from the ignition device (igniter) to the ignition coil decreases, and the ignition energy supplied from the ignition coil to the ignition plug decreases. Could not be obtained.

[0005] The ignition coil of the engine includes a primary coil to which a DC voltage is applied, and a secondary coil to generate a voltage corresponding to a change in current in the primary coil. The primary transistor is broadly divided into a full transistor type in which a current change is caused in the primary coil by interrupting the power supply to the primary coil, and a CDI type in which the electric charge stored in the capacitor is discharged to the primary coil in accordance with the ignition timing.

[0006] The above technical problem is that a system in which a change in current of a primary coil of an ignition coil greatly depends on an input voltage to an ignition device at an ignition timing, such as when a full transistor ignition device is employed,
Especially remarkable.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide an ignition method and apparatus for an engine in which a large ignition energy is always supplied to an ignition plug.

[0008]

In order to achieve the above object, the present invention provides a cranking means for cranking a crankshaft, an AC generator connected to the crankshaft, and an output of the AC generator. In an ignition device for an engine including a smoothing circuit for smoothing and an ignition device for generating ignition energy using an output of the smoothing circuit at an ignition timing, a timing at which the output of the smoothing circuit indicates a ripple is synchronized with the ignition timing. It is characterized by having.

According to the above feature, the peak of the voltage supplied to the ignition device coincides with the ignition timing, and a high voltage can be supplied from the ignition device to the ignition coil. Energy can be supplied, and the startability of the engine is improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a main part of an engine ignition system to which the present invention is applied.

The AC generator 24 is a crankshaft 1 of the engine.
The crankshaft 18 is connected to cranking means such as a kick pedal or a starter motor (not shown). The regulator 27 half-wave rectifies the AC voltage generated by the charge coil 25 of the AC generator 24 and outputs a DC voltage. The DC voltage output from the regulator 27 is supplied to a battery 29 and also to a DC load and a full transistor (dielectric discharge) ignition device 22 via a main switch 28.

The pulser coil 23 outputs one pulser signal to the full-transistor type ignition device 22 every one revolution of the engine. The full-transistor ignition device 22 includes an ignition transistor 20, and controls power supply to and cutoff from the primary coil 19a of the ignition coil 19 based on the timing at which the pulsar signal is detected. The ignition plug 30 is connected to the secondary coil 19b of the ignition coil 19. The secondary coil 19b supplies a high voltage generated according to a change in the current of the primary coil 19a to the ignition plug 30.

FIG. 2 is a diagram showing signal waveforms of main parts of the above-described embodiment. The timing at which the ignition transistor 20 is turned off, the output voltage of the AC generator 24 and the output voltage of the regulator 27 are shown in FIG. It is shown based on the rotational position.

In the present embodiment, the AC generator 24 is a single-phase
Because of the polar structure, its output voltage is 90 degrees of the crank angle.
The AC voltage has one cycle per degree. The AC voltage is half-wave rectified by the regulator 27, is substantially converted to a DC voltage, and is supplied to the primary coil 19a of the ignition coil 19.

Here, the output voltage of the regulator 27 is
It includes ripples synchronized with the cycle of the AC voltage. Further, as is well known, the full-transistor ignition device 22 cuts off the current to the primary coil 19a by the ignition transistor 20 to cause a current change in the primary coil 19a. A high voltage is generated according to. Therefore, the larger the voltage applied to the primary coil 19a at the timing when the ignition transistor 20 is cut off, the greater the ignition energy can be generated in the secondary coil 19b.

Therefore, in the present embodiment, the ignition device 22
Is turned off at the timing t1 at which the ripple component included in the DC voltage has the maximum value, in other words, at the timing at which the AC voltage has the maximum value.
The relative positional relationship between the rotor and the stator (both are shown) of the AC generator 24 and the relative positional relationship between the rotor and the crankshaft 18 are adjusted.

According to this embodiment, the ignition transistor 2
Since the interruption timing of 0 always coincides with the peak of the generated voltage, a high voltage can be supplied to the primary coil 19a of the ignition coil 19, and as a result, a large ignition energy can be supplied to the ignition plug 20.

In the above embodiment, the ignition device 2
2 has been described as a full transistor type,
The present invention is not limited to this, and the same effects can be obtained even with a CDI system or a combined ignition system combining a full transistor system and a CDI system.

[0019]

According to the present invention, since the timing at which the ignition transistor of the ignition device is cut off to cause a current change in the primary coil of the ignition coil coincides with the peak of the generated voltage, a large current change occurs in the primary coil. Can be done. Therefore, a large ignition energy can be supplied from the secondary coil of the ignition coil to the ignition plug, and the startability of the engine is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a signal waveform diagram of a main part of the embodiment of FIG.

[Explanation of symbols]

18 ... Crankshaft, 19 ... Ignition coil, 22 ... Full transistor type ignition device, 23 ... Pulsa coil, 24 ... AC generator, 25 ... Charge coil, 27 ... Regulator,
28: Main switch, 29: Battery, 30: Spark plug

Claims (3)

[Claims] A cranking means for cranking a crankshaft; an AC generator connected to the crankshaft; a smoothing circuit for smoothing an output of the AC generator; and an output of the smoothing circuit at ignition timing. A method for igniting an engine, comprising: an ignition device for generating ignition energy by utilizing the method described above, wherein the timing at which the output of the smoothing circuit indicates a ripple is synchronized with the ignition timing. 2. A cranking means for cranking a crankshaft; an AC generator connected to the crankshaft; a smoothing circuit for smoothing an output of the AC generator; and an output of the smoothing circuit at ignition timing. And an ignition device that generates ignition energy using the rotor, a rotor and a stator of the AC generator, and a crank so that the timing at which the output of the smoothing circuit indicates a ripple is synchronized with the ignition timing. An ignition device for an engine, wherein a rotational position of a shaft is defined. 3. The ignition device includes a primary coil and a secondary coil that are inductively coupled to each other, and an ignition transistor that disconnects and energizes the primary coil. 2. A high-voltage ignition energy is generated in a secondary coil by causing a current change in a primary coil.
An engine ignition device according to claim 1.