JPS632607Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field] This invention reliably advances the ignition timing in the high load range of the engine from the retarded state in the medium load range, thereby increasing output by achieving the required ignition timing of the engine. The present invention relates to an ignition timing control device for an internal combustion engine that aims at improving driveability as well as improving drivability.

[Background technology]

Generally, an internal combustion engine has an optimal ignition timing that matches various conditions such as its operating state and a set air-fuel ratio. In order to satisfy the required ignition timing of such an engine, an ignition timing control device is provided to obtain an ignition timing that meets the conditions.

FIG. 1 is a system diagram of a conventional ignition timing control device that utilizes negative pressure in a carburetor intake passage. The distributor 1 includes a boost controller 3 that controls the advance angle of ignition timing. The boost controller 3 includes a throttle valve 5 of a carburetor (not shown).
It is communicated with a downstream intake passage 7 through a negative pressure passage 9. The ignition timing is retarded by the negative pressure in the intake passage 7. In Fig. 2, when the load is small, the throttle valve 5
Due to the closing operation, the negative pressure in the intake passage 7 becomes stronger, so the boost controller 3 advances the ignition timing. As the load gradually increases, the throttle valve 5 is opened, so the negative pressure weakens, and the boost controller 3 of the vacuum advance angle device operates in the direction of decreasing the advance angle. If the load increases further and becomes a high load, the required ignition timing must be advanced as shown by the solid line in FIG. 2, but in the conventional device, the negative pressure weakens, so the ignition timing is maintained in a retarded state.

[Problems with background technology]

That is, in the conventional device, the negative pressure in the intake passage 7 weakens in proportion to the opening of the carburetor throttle valve 5, so that it is not possible to advance the ignition timing in the high load range. As shown by the broken line in Fig. 2, the retarded state in the medium load range is maintained up to the high load range, so that the required ignition timing cannot be satisfied, resulting in a lack of power and a deterioration in drivability.

[Purpose of invention]

Therefore, the purpose of this invention is to reliably advance the ignition timing in the high load range from the retarded state in the medium load range, despite the weakening of negative pressure due to opening of the throttle valve.
The purpose is to increase output and improve driveability by satisfying the engine's required ignition timing.

[Summary of the idea]

To achieve this purpose, this invention uses a vacuum advance device that retards the ignition timing using negative pressure in the intake passage in response to increases and decreases in load, and a vacuum tank that stores negative pressure in the low and medium load range. and a means for advancing the ignition timing from a retarded state by switching the negative pressure switching valve in a high load range and using the stored negative pressure to advance the ignition timing from a retarded state to achieve the required ignition timing. It is said to be composed of

[Effect of idea]

In this way, according to this invention, the negative pressure switching valve can be switched in a high load range to reliably advance the ignition timing from the retarded state caused by the conventional device using the negative pressure stored in the vacuum tank, thereby adjusting the required ignition timing of the engine. can be achieved to increase output. Therefore, for example, by improving the torque in the low speed range, it is possible to compensate for the power down caused by running uphill or using a cooler, thereby improving drivability. Further, in order to advance the angle in a high load range where negative pressure is weakened, there is no need to combine various control valve mechanisms, etc., as in conventional devices, and the structure is simple, so the reliability of the device is high.

[First Embodiment of the Invention] Next, an embodiment of this invention will be described based on the drawings. FIG. 3 is a system diagram showing a first embodiment of the ignition timing control device according to this invention. A throttle valve 8 is provided in an intake passage 6 communicating from the carburetor 2 to the combustion chamber 4 . In the distributor 10, the ignition timing is controlled to be retarded by the negative pressure in the intake passage 6 downstream of the throttle valve 8. That is, the distributor 10
The ignition timing is retarded by a first boost controller 12 and a second boost controller 14 of the vacuum advance device.

The first boost controller 12 communicates with the intake passage 6 downstream of the throttle valve 8 through a first negative pressure passage 16, and retards the ignition timing using negative pressure in accordance with increases and decreases in load.

The second boost controller 14 communicates with the intake passage 6 through a second negative pressure passage 18 that is parallel to the first negative pressure passage 16, and controls the advance angle when negative pressure is applied. In the second negative pressure passage 18, a vacuum tank 20 and a negative pressure switching valve 22, which store negative pressure in low and medium load ranges, are interposed in order from the side closest to the intake passage 6. The vacuum tank 20 has a built-in check valve 24 that allows flow only in the direction of the intake passage 6, and stores negative pressure. The negative pressure switching valve 22 is a three-way switching valve, and is switched on and off by a switch 26 that is controlled on and off depending on the opening degree of the throttle valve 8 or the opening degree of the throttle pedal. That is, when the switch 26 is turned off, the negative pressure switching valve 22 closes the second valve on the vacuum tank 20 side.
The negative pressure passage 18 is closed and the atmosphere is introduced into the second boost controller 14. When the throttle valve 8 is fully opened and the switch 26 is turned on, the negative pressure switching valve 22 is switched to close the atmospheric side and apply the negative pressure of the vacuum tank 20 to the second boost controller 14. As a result, the second boost controller 14 advances the ignition timing.

[Operation of the first embodiment] Next, the operation of the first embodiment will be explained. When the load is small, the throttle valve 8 closes, so the intake passage 6
strong negative pressure. Therefore, the first boost controller 12 advances the ignition timing. As the load increases, the throttle valve 8 gradually opens, so the negative pressure weakens, and the first boost controller 12 operates in the direction of decreasing the advance angle. At this time, since the throttle valve 8 is not fully open, the switch 26 is off, the second boost controller 14 is opened to the atmosphere, and negative pressure is stored in the vacuum tank 20 by the check valve 24.

When the load increases further and reaches the high load range,
Since the throttle valve 8 becomes fully open and the negative pressure further weakens, the first boost controller 12 further reduces the advance angle. At this time, when the throttle valve 8 is fully opened, the switch 26 is turned on, and the negative pressure switching valve 22 is switched to communicate with the second negative pressure passage 18. Therefore, the negative pressure stored in the vacuum tank 20 in the low/medium load range acts on the second boost controller 14 to advance the ignition timing.

FIG. 4 is a graph showing the ignition timing characteristics of the first and second boost controllers of the first embodiment, and FIG. 5 is a graph showing the engine load and the retardation state of the ignition timing. Since the negative pressure generated by the second boost controller 14, shown by the solid line in FIG. 4, is obtained in the high load range, it is possible to satisfy the required ignition timing in the high load range and increase the output, as shown by the broken line in FIG. . In addition, by keeping negative pressure in the vacuum tank 20 in the low and medium load ranges, the second boost controller 1 can be used in the high load ranges.
4, the ignition timing can be reliably advanced despite the weakening of the negative pressure due to the opening of the throttle valve 8. Furthermore, since its configuration is simple, its reliability is high.

[Second Embodiment of the Invention] FIG. 6 is a system diagram of an ignition timing control device showing a second embodiment. This embodiment is similar to the first embodiment, but has the following features. When the second boost controller 14a receives negative pressure, it operates in the retard direction, and the switch 26a turns off when the throttle valve 8 is fully open, that is, in a high load range, opening the second boost controller 14a side to the atmosphere. Further, as shown in FIG. 7, the second boost controller 14
The negative pressure stored in the vacuum tank 20 is used to maintain the retarded state of a until just before the high load range. In other words, as the load increases, the negative pressure in the intake passage weakens, and it becomes impossible to operate the second boost controller 14a in a retarded state. In the vicinity of this medium load range or above, the negative pressure stored in the vacuum tank 20 is used to maintain the retarded angle state and suppress the advanced angle state as a whole. Next, in a high load range, the retard state of the second boost controller 14a is canceled to realize an advance state. In other words, a state matching the required ignition timing as shown in the graph shown in FIG. 5 is realized.

[Operation of the second embodiment] In the second embodiment, when the load is small and the throttle valve 8 is closed, the switch 26a is on, so negative pressure acts on the second boost controller 14a, causing it to operate in the retard direction. There is. Therefore, as shown by the broken line in FIG. 7, the difference from the first boost controller 12 is obtained as an advance angle. As the load increases, the throttle valve 8 gradually opens, so the second
The negative pressure on the boost controller 14a side increases.
Therefore, the check valve 24 closes to maintain negative pressure in the vacuum tank 20. This negative pressure
As shown in the figure, since the angle is maintained constant, the second boost controller 14a maintains the retard state, and together with the decrease in the advance angle due to the decrease in negative pressure in the first boost controller 12, the advance angle is suppressed as a whole. Thus, the required ignition timing in the medium load range shown in FIG. 5 is achieved.

The negative pressure retained in the vacuum tank 20 is maintained even after the load increases and reaches near the high load range, as shown in FIG. 7, and the negative pressure on the first boost controller 12 side disappears. Due to this negative pressure, even after the operation of the first boost controller 12 is stopped, the second boost controller 14a is maintained in the retarded state, and the ignition timing is retarded.

When the load reaches a high load range, the switch 26a is turned off and the negative pressure switching valve 22a is switched. With this switching, the second boost controller 14a side is opened to the atmosphere, so the retardation operation is canceled.
Therefore, the vacuum advance angle device is relatively advanced. Therefore, the required ignition timing can be achieved and the output can be increased.

[Third Embodiment of the Invention] FIG. 8 is a system diagram of an ignition timing control device showing a third embodiment. In this embodiment, there is only one boost controller 30 that performs delay control according to increases and decreases in load. A vacuum tank 2 that stores negative pressure in the low/medium load range is located in parallel with the negative pressure passage 16 that communicates the boost controller 30 and the intake passage.
0 is set. A negative pressure switching valve 3 selectively communicates either the vacuum tank 20 or the negative pressure passage 16 with the boost controller 30.
2 are provided. This negative pressure switching valve 32 is the throttle valve 8
When fully open, that is, in a high load range, the vacuum tank 20 and boost controller 30
In the low/medium load range, the negative pressure passage 16 is communicated.

[Operation of Third Embodiment] In this embodiment, negative pressure acts on the boost controller 30 through the negative pressure passage 16 in the low/medium load range, thereby retarding the ignition timing. Further, during this time, negative pressure is stored in the vacuum tank 20 by the check valve 24. Negative pressure increases and throttle valve 8
When the switch 26 is fully opened, the switch 26 is turned on and the negative pressure switching valve 32 is switched. Therefore, the negative pressure passage 16
side is blocked, and the vacuum tank 20 side communicates with the boost controller 30. Since strong negative pressure is stored in the vacuum tank 20 in the low and medium load ranges, the ignition timing is advanced and controlled by this negative pressure. Therefore, the required ignition timing can be achieved and the output can be increased, and since parts are omitted from the previous embodiment, the engine can be made smaller.

[Industrial applicability]

The ignition timing control device according to this invention is capable of increasing the output in a high engine load range, has a simple structure, and has high reliability, and is useful when installed in an internal combustion engine as a power source for automobiles and the like.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a conventional ignition timing control device, and FIG. 2 is a diagram showing a graph of the engine load and the retarded state of the ignition timing. FIG. 3 is a system diagram showing a first embodiment of the ignition timing control device according to this invention;
FIG. 4 is a diagram showing a graph of the ignition timing characteristics according to the first embodiment, and FIG. 5 is a diagram showing a graph of the engine load and the retarded state of the ignition timing. Fig. 6 is a system diagram showing the second embodiment, Fig. 7 is a diagram showing a graph of ignition timing characteristics of the second embodiment, Fig. 8 is a system diagram showing the third embodiment, and Fig. 9 is a system diagram showing the ignition timing characteristics of the second embodiment. It is a figure which shows the graph of the ignition timing characteristic of 3rd Example. In the figure, 8 is a throttle valve, 14 is a second boost controller, 18 is a negative pressure passage, 20 is a vacuum tank, 22 is a negative pressure switching valve, 24 is a check valve, and 26 is a switch.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A vacuum advance device that retards the ignition timing using intake passage negative pressure in response to increases and decreases in load, and a vacuum tank that stores negative pressure in the low and medium load range and negative pressure. 1. An ignition timing control device for an internal combustion engine, comprising a switching valve, and means for switching the negative pressure switching valve in a high load range to advance control of ignition timing using the stored negative pressure. 2. A second boost controller is provided in the first boost controller that retards the ignition timing using intake passage negative pressure according to an increase or decrease in load, and a negative pressure passage communicates the second boost controller with the intake passage. A vacuum tank and a negative pressure switching valve are installed in order from the side closest to the intake passage to store negative pressure in low and medium load ranges, and this negative pressure switching valve is opened in the high load range and the vacuum tank is opened in the high load range. The ignition timing control device for an internal combustion engine according to claim 1, characterized in that advance control is performed by applying negative pressure stored in the second boost controller to the second boost controller. 3 A second boost controller is provided in the first boost controller that retards the ignition timing using intake passage negative pressure in accordance with an increase or decrease in load, and a negative pressure passage communicates the second boost controller with the intake passage. A vacuum tank and a negative pressure switching valve are installed in order from the side closest to the intake passage to store negative pressure in the low/medium load range, and this negative pressure switching valve is opened in the low/medium load range to switch off the vacuum tank. By applying negative pressure on the Yum tank side to the second boost controller, this second
The boost controller is operated in a retard direction, the negative pressure switching valve is closed in a high load range, and the negative pressure on the second boost controller side is released, thereby canceling the retard operation and controlling the advance angle. An ignition timing control device for an internal combustion engine according to claim 1, characterized in that the device has the following structure. 4 Equipped with a boost controller that retards the ignition timing using intake passage negative pressure in response to increases and decreases in load, and in parallel with the negative pressure passage that communicates the boost controller and the intake passage, negative pressure is applied in the low and medium load range. A vacuum tank for storage is provided, and a negative pressure switching valve is provided between the vacuum tank and the boost controller to selectively communicate either the negative pressure passage or the vacuum tank to the boost controller. The negative pressure switching valve is used to communicate the vacuum tank and the boost controller in a high load range, and to control the advance angle by causing the negative pressure stored in the vacuum tank to act on the boost controller. An ignition timing control device for an internal combustion engine according to claim 1, characterized in that the device has the following structure.