JPS6012945Y2 - Ignition timing control device - Google Patents

Description

[Detailed description of the invention] This invention relates to an ignition timing control device for an internal combustion engine.
・ ： ■゛□□ Conventionally, the ignition timing was delayed to prevent exhaust emissions from the internal combustion engine installed in a vehicle. This: Combustion is delayed, the maximum combustion temperature is lowered, the amount of nitrogen oxides (NOx) in the exhaust gas is reduced, and the gas temperature rises in the latter half of the expansion stroke and in the exhaust stroke, which corresponds to the reduction in effective work. and the promotion of hydrocarbon (HC) oxidation reactions in the exhaust system, resulting in NO
It is known to be extremely effective in reducing x and HC.

Furthermore, in order to quickly raise the temperature of the catalyst compound installed in the exhaust system after the engine is started, vacuum advance is stopped when the engine is cold.

In other words, the main advance angle of the vacuum advance angle is set to the required value in the exhaust gas recirculation state, so the ε ignition timing that activates the main advance angle when the engine is cold and has not started exhaust gas recirculation is the required condition. As the engine becomes more advanced, the exhaust temperature tends to drop, so the vacuum advance is stopped and the catalytic converter is quickly activated, and HC and CO (-carbon oxide) are reduced when the catalyst is not activated. .

However, if the vacuum advance angle is completely stopped during engine cooling, vehicle drivability may deteriorate, for example, when the intake manifold negative pressure drops to, for example, 200 mmHglJ when the vehicle is started, a so-called jerking phenomenon may occur, or the load may change from light to high loads. There are problems such as limpness and sluggishness during sudden acceleration, poor drivability under high loads, and sluggishness.

As a countermeasure to the above-mentioned problem, it may be possible to completely stop cutting the vacuum advance angle when cold, or in other words, to sufficiently advance the vacuum angle even when cold to prevent deterioration in vehicle drivability. Exhaust emissions deteriorate while the engine is heated up to a predetermined operating temperature.

The present invention was devised in view of the problems with conventional ignition timing control mechanisms for internal combustion engines as described above, and its purpose is to completely stop the ignition advance even when the engine is cold. This prevents deterioration of exhaust emissions by quickly activating the catalyst, and also prevents any stiffness or stagnation even when the engine is accelerated from this state, and after the engine has warmed up. An object of the present invention is to provide an ignition timing control device that can obtain stable engine operating performance by performing a required advance angle.

Since the present invention is distantly related to the above object, the present invention has an ignition timing control device for an internal combustion engine that includes a main advance mechanism and a sub advance mechanism that operate under negative pressure. The advance port of the carburetor of the internal combustion engine is connected to the atmosphere via a switching valve, and the main advance mechanism is connected to the advance port when the engine temperature is high (to the atmosphere when the engine temperature is low) by switching the first temperature switching valve. , are selectively communicated with each other, and the sub-advance mechanism is connected to the second
is connected to the sub-advance operation source after the engine is warmed up and the sub-advance operation source when the engine is cold through the temperature switching valve, and the sub-advance mechanism is connected by switching the second temperature switching valve. selectively communicates with the sub-advance operation source after the engine is warmed up when the engine temperature is high, and with the sub-advance operation source when the engine is cold when the engine temperature is low, and the second temperature switching valve. The present invention is characterized in that a negative pressure delay valve for maintaining the advance angle of the sub-advance mechanism is provided between the sub-advance mechanism operating source when the engine is cold.

In the present invention having the above configuration, when the engine is cold, atmospheric air is supplied to the main advance mechanism and negative pressure is supplied to the sub advance mechanism by the operation of the first and second temperature switching valves. The angle mechanism is stopped and the ignition angle is advanced only by the sub-advance mechanism, and the temperature of the catalytic converter is rapidly raised.

Even if the negative pressure is reduced by accelerating the engine in this state, the negative pressure will not be cut off at the moment of acceleration due to the action of the negative pressure delay valve, and no stiffness or stagnation will occur.

After the engine warms up, the first and second switching valves are switched to supply negative pressure from the carburetor's advance stage to the main advance mechanism to achieve the required advance angle. Negative pressure is supplied to the mechanism only during idling to obtain the necessary negative pressure advance characteristics after warming up.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, a vacuum advance angle device 1 includes a main advance angle mechanism 3 and a sub advance angle mechanism 5, and each mechanism 3, 5 has a diaphragm chamber (not shown), respectively, similar to a known vacuum advance angle device. Equipped with

The main advance angle mechanism '3 is communicated via a pipe 7 to a wax type temperature switching valve 9.

The temperature switching valve 9 constitutes the eleventh switching valve of the present invention, and in addition to the wax type shown in the figure, it can be a known temperature switching valve such as a bimetal type, a combination of a temperature sensitive switch and a solenoid valve, etc. .

The temperature switching valve 9 connects the main advance mechanism 3 to the atmosphere through the filter 11 when the engine (not shown) is cold, and connects the main advance mechanism 3 to the atmosphere from the main advance mechanism pipe 13 to the atmosphere after the engine has warmed up. It is configured to communicate with the advance port 17.

□The sub-advance mechanism 51 communicates with the bimetal type temperature switching valve 23 via the map pipe 21.

The temperature switching valve 23 is the second temperature switching valve of the present invention, and may be of any other known type. It communicates with an intake pipe 31 downstream of the carburetor 15 via a delay valve 29, and after the engine warms up, the sub-advance mechanism 5 communicates with a board 35 of the carburetor 6 via a pipe 33. .

The board 35 is installed downstream of the throttle valve during idling and upstream of the throttle valve during low load operation.

Referring to Fig. 2, when the engine is cold, the temperature switching valves 9, 2
The opening shown by the white triangle 3 is open, and the atmosphere is supplied to the main advance mechanism as shown by arrow A in the figure, and the negative pressure of the intake pipe 31 is supplied to the sub-advance mechanism as shown by arrow B. Therefore, the main advance angle is stopped and a sub advance angle is performed by the intake pipe negative pressure, and the temperature of the catalytic converter is rapidly raised.

Even if the negative pressure in the intake pipe is reduced by accelerating the engine in this state, the negative pressure will not be cut off at the moment of acceleration due to the action of the negative pressure delay valve 29, and no stiffness or stagnation will occur.

After the engine is warmed up, the ports of the temperature switching valves 9 and 23 shown by the black triangles open, and negative pressure is supplied from the carburetor advance port 17 to the main advance mechanism 3 as shown by arrow C in the figure. As shown by the arrow, negative pressure is supplied from the port 35 to the sub-advance mechanism 5 only during idling.

The present invention can prevent rapid temperature rise of the catalytic converter and deterioration of drivability when the engine is cold.

Note that the pipe 33 that communicates with the sub-advance mechanism 5 after warming up may be connected to the intake pipe instead of the port of the carburetor.
In this case, NOx increases slightly.

Alternatively, the pipe 27 that communicates with the sub-advance mechanism may be communicated with the advance port as indicated by a broken line 27' in FIG. 2, and the negative pressure there may be used for sub-advance.

Also, a filter 33' may be provided in place of the pipe 33 to eliminate the sub-advance angle during idling.

The main advance angle mechanism and the sub advance angle mechanism may be separate bodies.

As described above, the present invention uses first and second negative pressure advance mechanisms as negative pressure advance mechanisms, and includes first and second temperature switching valves in the operating circuits of these two negative pressure advance mechanisms. Since these are provided separately, each advance mechanism can be controlled separately depending on when the engine is cold and after it has warmed up, and the optimum ignition advance can be obtained depending on the engine operating condition. This allows the sub-advance mechanism to partially advance the angle even when the engine is cold, activating the catalyst quickly and preventing deterioration of exhaust emissions.Furthermore, after warming up, the main advance mechanism is activated. By the operation of , it is possible to perform a larger advance angle and obtain the required advance angle characteristics.

In addition, by installing a negative pressure delay valve in the operating circuit of the sub-advance mechanism, even if the engine is accelerated during a partial advance when the engine is cold, the negative pressure will not be cut off at that moment, and the advance will remain in that advance state for a certain period of time. Therefore, the engine does not become stiff or sluggish, and a decrease in operating performance can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional front view of an embodiment of the present invention, and FIG. 2 is a diagram illustrating the operating state of the embodiment of FIG. 1. 1...Vacuum advance angle device, 3...Main advance angle mechanism, 5...Sub advance angle mechanism, 9, 23
...Temperature switching valve, 29...Negative pressure delay valve.

Claims (1)

[Scope of utility model registration request] In an ignition timing control device for an internal combustion engine that includes a main advance angle and a sub advance mechanism that operate under negative pressure, the main advance mechanism is connected to the advance stage of the carburetor of the internal combustion engine and the atmosphere through a first temperature switching valve. (by switching the first temperature switching valve, the main advance mechanism is selectively communicated with the advance sport when the engine temperature is high and with the atmosphere when the engine temperature is low, and The angle mechanism is connected to a sub-advance operation source after engine warm-up and a sub-advance operation source during engine cooling via a second temperature switching valve, and
By switching the second temperature switch and the switching valve 9, the sub-advance mechanism is used as the sub-advance operation source after the engine is warmed up when the engine temperature is high, and as the sub-advance operation source when the engine is cold when the engine temperature is low. a negative pressure delay valve that selectively communicates with the angle operation source and further maintains the advance angle of the sub-advance mechanism between the second temperature switching valve and the sub-advance operation source when the engine is cold; I set up:
An ignition timing control device 1 characterized by