JPS6210468Y2 - - Google Patents

Description

[Detailed description of the invention] The invention relates to an ignition timing control device for an engine.
In particular, it relates to a negative pressure advance control device for ignition timing.

In an engine, when the amount of intake air decreases,
In view of the reduction in the combustion speed of the air-fuel mixture in the cylinder chamber, a negative pressure advance control device that advances the ignition timing in accordance with the degree of negative pressure in the intake pipe is incorporated into the engine ignition system.

The negative pressure advance control device usually includes a diaphragm device that advances the ignition timing in accordance with the negative pressure acting on the diaphragm device, and the diaphragm device includes: Generally, a negative pressure outlet port called an advance support is located upstream of the throttle valve when the throttle valve is in the fully closed position, and located downstream of the throttle valve when the throttle valve is opened to a predetermined opening or more. Negative pressure taken from the tank is introduced.

In the negative pressure advance angle control device as described above, excessive negative pressure advance is not performed during idling operation;
Although there is no risk of idling instability, negative pressure advance is not performed at all during idling operation. This is not to say that vacuum advance should not be performed at all during idling; rather, if a relatively small and moderate amount of negative pressure advance is performed even during idling, fuel efficiency can be improved without causing idling instability. can be improved.

Furthermore, it is preferable that the negative pressure advance angle reaches its maximum value quickly when the engine shifts from idling operation to load operation. Since no pressure advance is performed at all, it takes time for the negative pressure advance to reach its maximum value when the engine shifts from idle operation to load operation. In addition, in the negative pressure advance control device as described above, the timing at which the negative pressure advance starts is determined by the relative positional relationship between the negative pressure takeout port and the throttle valve. Manufacturing errors in the tuttle valve directly affect the negative pressure advance characteristics, making it difficult to perform negative pressure advance with high precision.

In view of the above-mentioned problems with conventional negative pressure advance angle control devices, the present invention makes it possible to perform an appropriate negative pressure advance angle during idling using a normal negative pressure advance angle control device. It is an object of the present invention to provide an ignition timing control device that is improved so as to advance the negative pressure angle with high precision and responsiveness.

According to the present invention, the present invention provides a negative pressure advance device that has a diaphragm device and advances the ignition timing in accordance with the negative pressure acting on the diaphragm device;
an intake pipe negative pressure outlet port located downstream of the throttle valve regardless of the opening degree of the throttle valve; a passage means for transmitting the negative pressure appearing at the intake pipe negative pressure outlet port to the diaphragm device; a detection means for detecting that the number corresponds to the idle rotation speed; and an ignition timing advance angle reducing means that is incorporated in an ignition electric circuit and reduces the advance angle of the ignition timing when the detection means detects the state. This is achieved by an engine ignition timing control device having the following features.

The ignition timing control device according to the present invention uses a normal negative pressure advance device to advance the ignition timing at an appropriate degree during idling. is located upstream of the throttle valve when it is in the fully closed position, that is, the idle position, and is located upstream of it when the throttle valve is opened beyond a predetermined opening degree. Instead of a support, a new intake pipe negative pressure is installed so that it is always located downstream of the throttle valve, regardless of the opening degree of the throttle valve, so that the intake pipe negative pressure is guided to the negative pressure advance device even during idling operation. Furthermore, even if the negative pressure is advanced to an appropriate degree during negative pressure operation other than idle operation, the ignition timing advance angle will be excessive during idle operation, so the engine speed will be lower than the idle speed. The engine is equipped with an ignition timing advance angle reduction means for reducing the advance angle of the ignition timing when the advance angle is significant, so that the negative pressure advance angle during idling operation is corrected to decrease.

That is, the ignition timing control device according to the present invention uses an intake pipe negative pressure outlet, which is always located downstream of the throttle valve, as a port for introducing the intake pipe negative pressure to the negative pressure advance device, regardless of the opening degree of the throttle valve. It is equipped with a port and an ignition timing advance angle reducing means that reduces the advance angle of the ignition timing when the engine speed is equivalent to the idle speed, and the combination of these two structures makes it possible to use the negative pressure advance device. It is characterized in that the advance angle during idle operation is advanced to an appropriate degree without making the advance angle during negative pressure operation inappropriate.

Furthermore, according to the ignition timing control device according to the present invention,
When the engine speed exceeds the idle speed,
By canceling the operation of the ignition timing advance angle reducing means, when the idling operation shifts to load operation, the ignition timing advance angle instantly increases to a value appropriate for load operation, and the advance angle during load operation increases. The start timing is determined by comparing the engine speeds, and as a result, the vacuum advance can be performed more accurately and appropriately than when using advance support.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings.

The attached FIG. 1 is a schematic diagram showing the main parts of one embodiment of the ignition timing control device according to the present invention. In the figure, reference numeral 1 designates a well-known distributor, in which a negative pressure advance device 2 is incorporated. The negative pressure advance device 2 has a diaphragm chamber 3, and when negative pressure is applied to the diaphragm chamber 3, the diaphragm 4 moves with the rod 5 to the left in the figure against the spring force of the spring 6. This acts on a cam mechanism (not shown) in the distributor 1 to advance the ignition timing.

7 indicates the engine intake system, which includes a bench lily 8 and a throttle valve 9.
is provided, and the air-fuel mixture metered by the throttle valve 9 is taken into the engine 11 via an intake manifold 10. The intake manifold 10 has an intake pipe negative pressure outlet port 12.
is provided. The intake pipe negative pressure outlet port 12 is always located downstream of the throttle valve 9, regardless of the opening degree of the throttle valve 9, and is always subjected to intake pipe negative pressure during engine operation. The intake pipe negative pressure outlet port 12 is connected to the diaphragm chamber 3 by a conduit 13. That is, the conduit 13 transfers the negative pressure appearing at the intake pipe negative pressure outlet port 12 to the diaphragm chamber 3.
It acts as a passage means to convey the information.

An igniter 14 is attached to the distributor 1. The igniter 14 is a pickup device 1 incorporated in the distributor 1.
Based on the ignition timing detected by 5 (see FIG. 2), an ignition coil (not shown) is operated.

As clearly shown in FIG. 2, the pick-up device 15 includes a rotor 16 which is rotationally driven by the engine 11 and has the same number of peaks as the number of engine cylinders.
and two pick-up elements 17 and 18 for detecting passage of the peak portion of the rotor. The pick-up element 18 is provided ahead of the pick-up element 17 in the direction of rotation of the rotor 16. Each of the pick-up elements 17 and 18 outputs an ignition signal each time the peak of the rotor 16 passes in front of it;
The ignition signals are respectively transmitted to the switching circuit 2 of the computer 19.
It is input to 0. The switching circuit 20 is configured to output a selected one of the ignition signals of the pickup elements 17 and 18 to the igniter 14 and the discrimination circuit 21. When the ignition signal of the pickup element 18 is applied to the igniter 14, the advance angle of the ignition timing is reduced compared to when the ignition signal of the pickup element 17 is applied to the igniter 14. That is, the igniter 14 and the pick-up device 15 act as means for reducing the ignition timing advance angle, and the amount of decrease in the ignition timing advance angle is determined by the amount by which the pick-up element 18
Determined by the amount of displacement of the mounting position.

The discrimination circuit 21 takes in the ignition signal as an engine rotation speed signal, and compares the value of the signal with a comparison setting value determined corresponding to the idle rotation speed,
When the value of the engine speed signal is equal to or smaller than the comparison set value, the ignition signal of the pick-up element 18 is outputted from the switching circuit 20, and when the value of the engine speed signal is larger than the comparison set value, the pick-up device The switching circuit 2 is configured so that the ignition signal of 17 is outputted from the switching circuit 20.
0 switching operation, and serves as a detection means for detecting that the engine speed is equivalent to the idle speed.

When the engine 11 is operated, the intake manifold 1
When negative pressure in the intake pipe is generated at 0, the negative pressure is transmitted from the intake pipe negative pressure outlet port 12 to the diaphragm chamber 3 via the conduit 13, and the diaphragm 4 resists the spring force of the spring 6 in response to this negative pressure. The rod 5 is displaced to the left in the figure, and the rod 5 is accordingly moved to the left, thereby advancing the negative pressure. Since this negative pressure advance is performed in response to the negative pressure appearing at the intake pipe negative pressure outlet port 12, it is also performed during idle operation, and the maximum negative pressure advance is performed during this idle operation. However, at this time, the discrimination circuit 21 has determined that the engine speed is at or below a predetermined value determined according to the idle speed, so the switching circuit 20 switches the ignition signal generated by the pick-up element 18 to the igniter. 14. As a result, at this time, that is, during idling operation, the ignition timing controlled by the igniter 14 is delayed compared to when the ignition timing generated by the pick-up element 17 is input to the igniter 14, in other words, the advance angle of the ignition timing is reduced. As a result, even if the negative pressure advance angle is set to the maximum value during idling operation, the overall ignition timing advance angle is set to a certain small value that is appropriate during idling operation. The advance angle during idle operation can be freely set by selecting the mounting position of the pick-up element 18 relative to the pick-up element 17.

When the opening degree of the throttle valve 9 increases and the engine 11 shifts from idle operation to load operation,
When the engine speed increases accordingly and exceeds the comparison set value, the switching circuit 20 is switched by the operation of the discrimination circuit 21, and the igniter 14 is connected to the pickup element 1.
The ignition signal generated by the pickup element 17 is now given instead of the ignition signal generated by the pickup element 8. At this time, the delay in the ignition timing controlled by the igniter 14 is eliminated, so that the overall advance angle increases instantaneously, and the advance angle is made in accordance with the load operation at that time.

FIG. 3 is an electrical circuit diagram showing another embodiment of the ignition timing control device according to the present invention. Furthermore, the third
In the figure, parts corresponding to those in FIG. 2 are designated by the same reference numerals as in FIG. 2. In this embodiment, the pickup device 15 is composed of a rotor 16 and one pickup element 17, and the ignition timing signal generated by the pickup element 17 is connected to the ignition timing control circuit 22 and the embodiment described above. It is designed to be input to a discriminating circuit 21 similar to the above. The ignition timing control circuit 22 delays the ignition signal given by the pick-up element 17 for a predetermined period of time when the discrimination circuit 21 determines that the engine speed is below a comparison set value determined according to the idling speed. On the other hand, when the determination circuit 21 determines that the engine speed is equal to or higher than the comparison set value, the ignition timing signal generated by the pick-up element 17 is outputted to the igniter 14 instantly without delay. It is now output.

In this embodiment as well, the negative pressure advance is performed by a negative pressure advance device similar to the negative pressure advance device shown in FIG. Negative pressure advance may be performed. Even if the maximum negative pressure advance is performed during idling, the ignition timing controlled by the igniter 14 is delayed due to the action of the ignition timing control circuit 22, and therefore the overall advance angle during idling is the same as when idling. It is set to some suitable small value.
Further, when the engine 11 shifts from idle operation to load operation and the engine speed increases accordingly and exceeds the comparison set value, the ignition timing controlled by the igniter 14 is controlled by the action of the ignition timing control circuit 22. The delay is eliminated, and at this time the overall ignition timing increases, and the advance angle is made in accordance with the load operation at that time.

Incidentally, in the above-mentioned embodiment, it was determined whether or not the engine was idling by giving the engine speed signal to the determination circuit 21, but the present invention is not limited to this. , it may be determined whether the engine is being operated at idle based on the vehicle speed. When determining whether or not the engine is running at idle based on the vehicle speed, it may be assumed that the engine is running at idle when the vehicle speed is essentially 0.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto, and those skilled in the art will recognize that various embodiments are possible within the scope of the present invention. It would be obvious to

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of the ignition timing control device according to the present invention, FIG. 2 is an electric circuit diagram showing one embodiment of the ignition electric circuit according to the present invention, and FIG. FIG. 3 is an electric circuit diagram showing another embodiment of the invented electric circuit for ignition. 1 - Distributor, 2 - Negative pressure advance device,
3 - diaphragm chamber, 4 - diaphragm, 5 - rod, 6 - spring, 7 - engine intake system, 8 - bench lily, 9 - throttle valve, 10 - intake manifold, 11 - engine, 12 - intake pipe negative pressure outlet port , 13~conduit, 14~igniter, 15
~ Pickup device, 16 ~ Rotor, 17, 18
~Pickup element, 19~Computer, 20
~Switching circuit, 21~Discrimination circuit, 22~Ignition timing control circuit.

Claims (1)

[Scope of utility model registration request] A negative pressure advance device that has a diaphragm device and advances the ignition timing in accordance with the negative pressure acting on the diaphragm device, and an intake that is located downstream of the throttle valve regardless of the opening degree of the throttle valve. A pipe negative pressure outlet port, a passage means for transmitting the negative pressure appearing at the intake pipe negative pressure outlet port to the diaphragm device, a detection means for detecting that the engine speed is equivalent to the idle speed, and an ignition electric circuit. An ignition timing control device for an engine, characterized in that it has an ignition timing advance angle reducing means incorporated therein, which reduces the advance angle of the ignition timing when the detecting means detects the condition.