JPS6024946Y2 - Internal combustion engine ignition timing control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition timing control device for an internal combustion engine, and more particularly to an ignition timing control device that advances the ignition timing during idling operation in order to reduce fuel consumption.

With this type of ignition timing control variable, the idle port located slightly downstream of the throttle valve when the throttle valve is fully closed is connected to the diaphragm chamber of the vacuum advancer of the distributor. (when closed), the idle port becomes negative pressure and negative pressure advance is performed.

However, even during deceleration, as long as the throttle valve is in the idle position, the angle will be advanced.
There was a problem in that during deceleration, the engine advanced too much, causing misfire and emitting a large amount of unburned hydrocarbon (HC).

The present invention was devised to solve this problem, and is designed to prevent the idle advance mechanism from acting during deceleration in an ignition timing control device that is equipped with a mechanism that performs negative pressure advance during idling. The purpose is to prevent misfires from occurring.

In the present invention, in an internal combustion engine equipped with the idle advance mechanism as described above, a port is installed at a position in the intake passage that is downstream of the throttle valve when the valve is fully closed, and upstream of the valve when the throttle opener or throttle positioner is activated. By drilling this port and communicating this port with the diaphragm chamber of the vacuum advancer of the distributor, the idle advance angle is performed, but the idle advance angle is cut during deceleration.

That is, during idle, the idle angle is advanced by the negative pressure from the idle port, but during deceleration, the atmospheric pressure from the newly provided port is applied to the negative pressure from the idle port, and the idle angle advance mechanism is effectively activated. This is to prevent it from working.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 schematically shows an embodiment of an ignition timing control device for an internal combustion engine according to the present invention.

An advance port 2 provided in an intake passage 1 of an internal combustion engine is connected via a passage 3 to a main diaphragm chamber 6 of a vacuum advancer 5 of a distributor 4.

Also, the throttle valve 7 is in the idle state (fully closed state)
Position of? a, the idle port 20 located slightly downstream of the throttle valve 7 is connected to the diaphragm chamber 15 of the vacuum advancer 5 via a passage 22, and the negative pressure of the idle port 20 during idle operation is controlled by the vacuum advancer. The advancing angle at idle is performed by acting on the sub-diaphragm chamber 15 of the sensor 5.

The throttle opener 8 is a type of deceleration control mechanism, and as is well known, it moves the throttle valve 7 to the fully closed position (
idle position)? Maintain position 7b slightly wider than a. Misfire during hip deceleration and associated unburned HC.
This device prevents gas from being discharged, and the throttle valve 7 is gradually closed as the speed of the vehicle decreases.

Therefore, the throttle opener 8 includes a negative pressure operating chamber 9 connected to the intake manifold, a diaphragm 10 driven by the negative pressure of the manifold, an atmospheric chamber 11 into which the atmosphere is introduced, and levers that control the opening degree of the throttle valve 7. 12
etc.

The structure and operation of the throttle opener 8 itself have been well known.

In FIG. 1, the intake passage 1 includes a throttle valve 7.
When the throttle valve 7a is in the fully closed position (idle position), the throttle opener 8 is located downstream of the throttle valve 7a.
When the throttle valve 7 is in a slightly open position due to the action of a deceleration control device such as
A port 13 is provided upstream of the port 13.

This port 13 is connected to the distributor 4 via a passage 14.
The vacuum advancer 5 is connected to the sub-diaphragm chamber 15 of the vacuum advancer 5.

Thus, the vacuum advancer 5 includes main and sub diaphragm chambers 6, 15, as shown in FIG. 1, and these diaphragm chambers 6, 15 operate independently.

Such a double-barreled vacuum advancer 5 itself is already known.

According to the present invention, when the internal combustion engine is in normal idle operation and the throttle valve 7 is already in the fully closed position (idle position) 7a, not only the idle port (not shown) but also the port 13 are throttled. Since it is located on the downstream side of the valve 7, negative pressure is introduced into the sub-diaphragm chamber 15 of the vacuum advancer 5, and the idle angle is advanced.

Also, during deceleration, the engine speed is relatively high, so there is a high negative pressure inside the intake manifold, but the throttle valve 7 is maintained at the slightly open position 7b by the action of the throttle opener 8, so the port 13 is connected to the throttle valve. Located upstream of the valve 7, the negative pressure of this port 13 is low and close to atmospheric pressure.

FIG. 2 is a graph showing the absolute value of the negative pressure of the port 13 (vertical axis) relative to the opening degree of the throttle valve 7 (horizontal axis).

Also, the absolute value of the negative pressure of the idle port 20 and the port)
The absolute value of the total negative pressure (negative pressure acting on the sub-diaphragm chamber 15) of 13.20 is also shown.

That is, the throttle valve 7 is in the fully closed position (idle position).
? a, the absolute value of the negative pressure is high as shown in 1 in FIG. When it is in the open position, the absolute value of the negative pressure is much lower than the subdiaphragm chamber operating limit pressure and is close to atmospheric pressure, as shown at 2 in Figure 2.

Therefore, during deceleration, although the negative pressure of the idle port 20 is acting, the pressure of the port 13 is close to atmospheric pressure, so the pressure of the sub-diaphragm chamber 15 of the vacuum advancer 5 becomes close to atmospheric pressure, and the vacuum advancer Do not advance the idle angle by 5.

This prevents misfire during deceleration, and the accompanying generation of unburned HC gas.

In the illustrated embodiment, even during deceleration, the negative pressure in the advance port 2 is transmitted to the main diaphragm chamber 6 of the vacuum advancer 5, so slight advance angle control is performed.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an embodiment of the ignition timing control system for an internal combustion engine according to the present invention, and Fig. 2 shows the opening of the throttle valve, the negative pressure (absolute value) of the port 13 provided in the intake passage, and the idle port 20. FIG. 2 is a diagram showing the relationship between negative pressure (absolute value) and the sum of these negative pressures (absolute value). 1...Intake passage, 2...Advance port, 4...Distributor, 5...
...Vacuum advancer, 7...Throttle valve, Deceleration control mechanism (throttle opener), 13...Port.

Claims (1)

[Scope of utility model registration request] An idle advance mechanism that advances the ignition timing during idle operation by introducing negative pressure from the idle port 20 of the internal combustion engine into the diaphragm chamber 15 of the vacuum advancer 5 of the distributor 4, and a throttle valve during deceleration. 7 is slightly open from the fully closed position 7a.
a deceleration control mechanism 8 for maintaining the throttle valve 7 at the fully closed position 7a, and a port 13 located on the downstream side of the valve when the throttle valve 7 is in the fully closed position 7a, and located on the upstream side of the valve when the throttle valve 7 is slightly opened, is opened in the intake passage 1. , the port 13 is communicated with the diaphragm chamber 15 of the vacuum advancer 5, and during idling, the negative pressure from the idle port is used to advance the angle, but during deceleration, the atmospheric pressure from the port 13 is used to advance the idling angle. An ignition timing control device for an internal combustion engine, characterized in that an advance mechanism is substantially not activated.