JPH0220466Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an ignition device for an internal combustion engine that includes a DC-DC converter that injects ignition energy into the secondary side of an ignition coil in addition to a normal ignition device.

Conventionally, such ignition devices for internal combustion engines have been disclosed, for example, in Japanese Patent Application Laid-open Nos. 11342-1982 and 1982-11342.
There are some such as those described in Publication No. 124672.

The basic structure of such an ignition system for an internal combustion engine will be explained with reference to FIG.

In the figure, this ignition system first supplies voltage from a battery 1 via an ignition switch 2 to a primary coil 3a of a four-terminal ignition coil 3 whose primary side and secondary side are separated.

The full-torque ignition device 4, which is a normal ignition device, generates an ignition timing signal P1 by waveform-shaping a detection signal from a pickup coil (not shown) installed opposite to a rotor attached to a shaft in a distributor _. The ignition circuit 5 which inputs the ignition circuit 5 controls the switching transistor 6 to turn on and off, cuts off the primary current of the ignition coil 3, and generates a high voltage of -several KV in the secondary coil 3b of the ignition coil 3.

The high voltage generated in the secondary coil 3a of the ignition coil 3 is sequentially distributed to the spark plugs 8A to 8D of each cylinder by the distributor 7 to start ignition discharge.

On the other hand, in the DC-DC converter 10, when the ignition signal _P2 from the full-torque ignition device 4 is input, the control circuit 11 operates the oscillation circuit 12, which is made of a monomulti, for example, for a predetermined period of time, and the emitter follower is activated. A drive circuit 13 consisting of circuits etc. controls the switching transistor 14 to turn on and off, intermittents the current flowing to the primary coil 15a of the step-up transformer 15, and generates a high voltage in the secondary coil 15b of the step-up transformer 15. let

The high voltage generated in the secondary coil 15b of this step-up transformer 15 is transferred to diodes 16 and 17.
A high voltage of about -2 KV obtained by full-wave rectification and smoothing by a coil 18 and a capacitor 19 is injected into one end of the secondary coil 3b of the ignition coil 3.

Thereby, the high voltage is supplied to the spark plugs 8A to 8D via the secondary coil 3b of the ignition coil 3, extending the discharge duration, stabilizing combustion, and improving fuel efficiency.

In this way, in this ignition system for internal combustion engines, the DC-DC converter is operated regardless of the engine speed, but the effect of injecting ignition energy by the DC-DC converter is mainly in the idling speed range. DC is noticeable in the high engine speed range.
- Operating the DC converter has the disadvantage of increased power consumption.

Therefore, the present applicant has previously proposed an ignition system for an internal combustion engine that is equipped with an operation stop means that stops the operation of the DC-DC converter when the engine speed exceeds a predetermined engine speed, for example, 2000 rpm. (For example, Patent Application No. 57-210569).

In such an ignition system for an internal combustion engine, when the engine speed is below a predetermined engine speed,
Since the DC-DC converter operates, the ignition current and ignition voltage become as shown in Figure 2, for example, and the discharge time DS becomes longer, but when the engine speed exceeds a predetermined number, the DC-DC converter is activated. Since it is inactive, the ignition current and ignition voltage become as shown in FIG. 3, for example, and the discharge time DS becomes shorter.

By the way, in general, internal combustion engines use a centrifugal advance device (governor advance device) that advances the ignition timing according to the engine speed, and a vacuum advance device (vacuum advance device) that advances the ignition timing according to the suction negative pressure. The ignition timing is optimally controlled by mechanically acting on the shaft of the distributor to change the relative position between the rotor and the pickup coil.

When using such an ignition timing control device,
When the engine enters a no-load (N/L) deceleration state from high-speed operation, the throttle valve becomes fully closed, the engine speed is high, and the pressure in the intake pipe becomes negative. As is clear from the rotational speed-advanced angle characteristics and vacuum degree-advanced angle characteristics shown in FIGS. 4 and 5, the ignition timing is advanced.

By the way, if the DC-DC converter is deactivated and ignition is performed using only a normal ignition device,
The relationship between the advance angle, the misfire rate indicating the misfire cycle of engine combustion as a percentage, and the amount of unresolved hydrocarbon (HC) in the exhaust gas is shown, for example, in FIGS. 6 and 7.

Therefore, as mentioned above, if the DC-DC converter is not activated when the engine speed exceeds a predetermined speed, the ignition timing will advance when the engine enters no-load deceleration from high-speed operation. As a result, the misfire rate is high and the amount of unburned HC is large, resulting in irregular combustion.As a result, the engine shakes the moment it starts to decelerate, causing vibrations in the car body and causing a sense of anxiety and fear to the driver. This has the disadvantage of giving .

This idea was made in consideration of the above points, and is designed to prevent HC from being emitted due to misfire when decelerating from high-speed driving, and to prevent the vehicle body from vibrating and causing a sense of anxiety or fear to the driver. The purpose is to

Therefore, the ignition device for an internal combustion engine according to this invention is designed to release the deactivation of the DC-DC converter when the throttle valve closes even if the engine is operated in a high rotation range.

Hereinafter, embodiments of this invention will be described with reference to FIG. 8 and subsequent figures of the accompanying drawings.

FIG. 8 is a circuit diagram showing the main parts of an ignition system for an internal combustion engine implementing this invention. Note that the same parts as in FIG. 1 are given the same reference numerals, and explanations of those parts will be omitted.

In the figure, the control circuit 21 is the oscillation circuit 12.
It is a circuit that operates for a predetermined period of time, and the resistor R ₁
~R ₁₁ , capacitor C ₁ ~C ₃ , Zener diode
ZD ₁ , diode D ₁ , and transistors Q ₁ to _{Q 3} , which receives an ignition signal P ₂ from a full-torque ignition device (not shown) and outputs an operating pulse DP with a predetermined pulse width to the oscillation circuit 12 .

That is, this control circuit 21 first shapes the waveform of the ignition signal P ₂ using the resistor R ₁ and the Zener diode ZD ₁ to generate a predetermined pulse, and applies this pulse to the capacitor C _{1 to} At the same time as charging, apply to the base of transistor _Q1 .

As a result, the transistor Q ₁ is turned on and the transistor Q ₂ is turned off. If the transistor Q ₃ is turned off at this time, the operating pulse DP becomes high level "H", and this state turns off the ignition. Even after the signal P ₂ is no longer input, the transistor Q ₁ remains on due to the discharge of the capacitor C ₁ , so it continues for a predetermined period of time, and after that predetermined period of time, the transistor Q ₁ turns off and the transistor Q ₂ is in the on state, so the operating pulse DP
becomes low level “L”.

Therefore, when the transistor _Q3 is in the on state, the control circuit 21 also performs the following:
Even if the ignition signal _P2 is input, the operating pulse DP is “H”
do not become. In other words, the oscillation circuit 12 does not operate.

The operation stop circuit 22 is a circuit that stops the operation of the DC-DC converter when the engine speed exceeds a predetermined engine speed, and counts the ignition signal _P2 with a counter 23 and calculates the count value. The integration circuit 23 integrates to generate an integrated voltage VC according to the engine speed, while the constant voltage VF generated from the battery voltage VB is divided by resistors R ₁₂ and R ₁₃ to generate a reference voltage VD. The comparator 25 compares the integrated voltage VC and the reference voltage VD, and VC>VD.
Outputs an operation stop signal PS that becomes "H" when .

On the other hand, the throttle close switch 26 is a throttle close detecting means, and a resistor _R14 detects the battery voltage.
When the throttle valve 28 provided in the intake manifold 27 of the engine is pulled up to VB and the throttle valve 28 is closed, it is turned on, and at this time, an operation stop release signal PN of low level "L" is output.

Note that the throttle close switch 26 can be constructed from an idle position contact of a throttle switch for detecting the opening degree of the throttle valve 28.

Then, the operation stop signal PS from the operation stop circuit 22 and the operation stop release signal PN from the throttle close switch 26 are inputted to an AND circuit 29 which is an operation stop release means, and the output of this AND circuit 29 is inputted. It is input to the base of the transistor _Q3 of the control circuit 21.

The structure and structure of a normal ignition system (not shown)
The configuration of the not-illustrated portions of the DC-DC converter is the same as that in FIG. 1, so the explanation will be omitted.

Next, the operation of this embodiment configured as described above will be explained.

First, if the engine speed is equal to or lower than the engine speed corresponding to the reference voltage VD of the operation stop circuit 22, the comparison result of the comparator 25 that compares the integrated voltage VC of the integrating circuit 24 and the reference voltage VD is VC≦ Since it becomes VD, the operation stop signal PS is not output (it is "L").

Therefore, the transistor Q ₃ of the control circuit 21
is in the off state, so ignition signal ₂ is connected to control circuit 2.
1, the operating pulse DP is output to the oscillation circuit 12 for a predetermined period of time, and this DC-DC converter is operated.

On the other hand, when high-speed operation starts and the engine speed exceeds the engine speed corresponding to the reference voltage VD,
Since the comparison result of comparator 25 becomes VC>VD,
The operation stop signal PS is output from the operation stop circuit 22 (becomes "H").

At this time, if the throttle close switch 26 is in the OFF state, that is, the throttle valve 28 is in the open state, the operation stop release signal PN is not output (it is "H"), so the AND circuit 29 is in the open state. ing.

Therefore, when the operation stop signal PS from the operation stop circuit 22 is input to the transistor Q ₃ of the control circuit 21, the transistor Q ₃ is turned on, and even if the ignition signal P ₂ is input to the control circuit 21, it will not operate. Since the pulse DP is not output (remains "L"), this DC-DC converter no longer operates.

However, when the accelerator pedal is released from this high-speed operating state and the throttle enters deceleration into no-load (N/L) operation, the throttle valve 28 closes and the throttle close switch 26 turns on, releasing the operation stoppage. Since the signal PN is output (becomes "L"), the AND circuit 29 is closed.

As a result, the operation stop signal PS from the operation stop circuit 22 is no longer input to the transistor Q ₃ of the control circuit 21, and the transistor Q ₃ is turned off, so that the ignition signal P ₂ is input to the control circuit 21. An operating pulse DP is output to the oscillation circuit 12 each time the DC-DC converter is operated, and ignition energy is injected into the secondary coil of the ignition coil (not shown).

In this way, in this ignition system for an internal combustion engine, when the engine speed is below a predetermined engine speed N 0 and when the engine speed is below the predetermined engine speed N ₀ , Even if the rotation advance N exceeds ₀ , when there is no load (N/L), DC-
Activate the DC converter to inject ignition energy into the secondary side of the ignition coil.

FIG. 10 and FIG. 11 are characteristic diagrams showing an example of the relationship between the advance angle, the misfire rate, and the amount of unused HC when the DC-DC converter is operated.

As is clear from these figures, when the DC-DC converter operates, the discharge time is extended, so even if the advance angle is large, the misfire rate and the amount of unused HC are reduced.

Therefore, by making the ignition system for an internal combustion engine operate the DC-DC converter even when decelerating from high speed no-load rotation,
The vehicle body will not vibrate due to engine vibration due to irregular combustion.

Furthermore, since the amount of HC generated during such operation is reduced, it is also effective in terms of exhaust emissions.

It goes without saying that the configurations of the ordinary ignition device and DC-DC converter are not limited to the configurations of the above embodiments.

As explained above, according to this invention, the vibration of the vehicle body during deceleration from high-speed driving, which causes a feeling of anxiety or fear to the driver, is eliminated.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of a conventional ignition system for an internal combustion engine, and FIGS. 2 and 3 are used to explain the operation when the ignition system for an internal combustion engine shown in FIG. 1 is provided with an operation stop means. Waveform diagrams showing different examples of ignition current and ignition voltage; FIGS. 4 and 5 are diagrams showing an example of advance characteristics of a centrifugal advance device and a vacuum advance device;
Figures 6 and 7 are graphs showing an example of the relationship between the advance angle and the amount of unburned HC when the DC-DC converter is not operating, and Figure 8 is an internal combustion engine that implements this invention. 9 is a diagram showing the operating range of the DC-DC converter of this embodiment, and FIGS. 10 and 11 are circuit diagrams showing the main parts of the ignition system for
FIG. 3 is a diagram illustrating an example of the relationship between the advance angle, the misfire rate, and the amount of unused HC when the DC-DC converter is operated. 1...Battery, 2...Ignition switch, 3...Ignition coil, 4...Full type ignition system, 7...Distributor, 8A to 8D...
Spark plug, 10...DC-DC converter, 12
...Oscillation circuit, 13...Drive circuit, 15...
Step-up transformer, 21... Control circuit, 22... Operation stop circuit, 26... Throttle closing switch, 28
...Throttle valve, 29...AND circuit.

Claims (1)

[Scope of utility model registration request] A DC-DC converter that injects ignition energy into the secondary side of the ignition coil in addition to the normal ignition system of the engine, and the DC-DC converter is activated when the engine speed exceeds a predetermined engine speed. In the ignition system for an internal combustion engine, the ignition system for an internal combustion engine is equipped with an operation stop means for stopping the throttle valve, and a throttle close detection means for detecting that the throttle valve is in the closed state; An ignition device for an internal combustion engine, characterized in that an ignition device for an internal combustion engine is provided with an operation stop release means for canceling the operation stop caused by the operation stop means when this is detected.