JPH0244059Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a device that controls the ignition timing in an internal combustion engine according to the load and knocking of the engine using a negative pressure advance mechanism provided in a distributor. It is related to.

[Conventional technology]

A device for controlling the ignition timing in an internal combustion engine according to engine load and knocking using a negative pressure advance mechanism provided in a distributor was proposed in Japanese Patent Laid-Open No. 57-56664 as a prior art. This system adjusts the ignition timing of the engine by connecting the negative pressure advance mechanism in the distributor to the advance port located slightly upstream of the closed position of the throttle valve via a negative pressure transmission passage. While controlling according to the load, a switching valve is provided in the negative pressure transmission passage to open the negative pressure chamber in the negative pressure advance mechanism to the atmosphere if knocking occurs in the engine. Knocking is sometimes suppressed by retarding the ignition timing.

[The problem that the idea attempts to solve]

However, in this prior art, when knocking occurs in the engine, the negative pressure chamber in the negative pressure advance mechanism is opened to the atmosphere to retard the ignition timing, and the amount of retardation is large. Therefore, due to the retard control in response to knocking, the output of the engine is significantly reduced, resulting in disadvantages such as deterioration of engine drivability.

The purpose of the present invention is to solve this problem, that is, the deterioration of drivability due to retard control due to ignition timing notching, by developing a negative pressure advance mechanism that performs ignition timing advance control. By using a two-stage negative pressure advance mechanism in which a pressure advance mechanism and a second negative pressure advance mechanism are arranged in series, knocking occurs frequently when accelerating from extremely low loads. The object is to solve this problem without causing any problems and while maintaining the ignition timing suitable for idling operation.

[Means to solve the problem]

In order to achieve this objective, the present invention provides a first distributor in which the ignition timing is advanced in relation to the intake negative pressure downstream of the throttle valve.
The negative pressure advance mechanism is provided in series with a second negative pressure advance mechanism that also controls the advance of the ignition timing in relation to the intake negative pressure downstream of the throttle valve, and the second negative pressure advance mechanism is arranged in series. In the negative pressure transmission passage connecting the second negative pressure chamber in the mechanism and the downstream side of the throttle valve, the second negative pressure chamber is communicated with the atmosphere in response to a knocking signal from a knocking sensor provided in the engine. A first switching valve in the first negative pressure advance mechanism is provided. 1. When there is no close signal from the throttle valve in the negative pressure transmission passage connecting the negative pressure chamber to the advance port provided slightly upstream of the throttle valve's closed position and the negative pressure port downstream of the throttle valve, The first negative pressure chamber communicates only with the advance port, but a second switching valve is provided that switches the first negative pressure chamber to communicate only with the negative pressure port in response to a closing signal from the throttle valve. did.

[Effect]

During idling operation with the throttle valve in the closed position, the first switching valve is switched to communicate the second negative pressure chamber in the second negative pressure advance mechanism with the atmosphere in response to the closing signal of the throttle valve, while the second switching valve is switched to communicate with the atmosphere. , the throttle valve close signal switches the first negative pressure chamber in the first negative pressure advance mechanism to communicate only with the negative pressure port downstream from the throttle valve, and negative pressure acts only on the first negative pressure chamber. Therefore, the ignition timing in the idling operating range of the engine is maintained at an ignition timing suitable for idling operation only by the first negative pressure advance mechanism.

Then, when the throttle valve is opened, the first switching valve is switched to apply intake negative pressure to the second negative pressure chamber in the second negative pressure advance mechanism, and the second negative pressure advance mechanism is advanced. On the other hand, the second switching valve switches the first negative pressure chamber in the first negative pressure advance mechanism to communicate only with the advance port, and also connects the first negative pressure chamber in the first negative pressure advance mechanism to the advance port by opening the throttle valve. Since pressure is generated and this negative pressure is transmitted to the first negative pressure chamber, the ignition timing in this partial load operating range of the engine is determined by the advance value by the second negative pressure advance mechanism. The lead angle is controlled to a value that is the sum of the lead angle value provided by the lead angle mechanism.

In this case, the negative pressure generated at the advance port when the throttle valve opens is smaller on the atmospheric pressure side than the negative pressure at the negative pressure port downstream from the throttle valve. The first negative pressure chamber in the first negative pressure advance mechanism,
By switching the communication from the negative pressure port to the advance port by opening the throttle valve, the ignition timing in the partial load operating range of the engine is prevented from being overadvanced than the ignition timing at the knocking limit at that time. Therefore, the ignition timing in this partial load operating range can be controlled to an appropriate value that reliably controls the occurrence of knocking.

When knocking occurs in the engine in the operating range where the throttle valve is open, the first switching valve communicates the second negative pressure chamber in the second negative pressure advance mechanism with the atmosphere based on the throttle valve close signal. By switching, the advance operation of the ignition timing by the second negative pressure advance mechanism is canceled, so that the ignition timing at the time of knocking is advanced by the amount that was advanced by the second negative pressure advance mechanism. The ignition timing is retarded, thereby suppressing knocking, and while the retard control of the ignition timing to control this knocking is carried out only by the second negative pressure advance mechanism, even at this time, the ignition timing is retarded. The first negative pressure advance mechanism is
Since the advanced angle is maintained in accordance with the negative pressure at the advance port and is not retarded as much as in the prior art described above, drivability is improved when retarding the angle in response to knocking of the ignition timing. It is possible to reduce the deterioration of

[Effect of idea]

Therefore, according to the present invention, it is possible to reduce deterioration in drivability when knocking is suppressed by retard control of the ignition timing, and to adjust the ignition timing in the idling operating range and part load operating range of the engine to prevent knocking from occurring. This has the effect of reliably controlling the value to an appropriate value while preventing.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 indicates an intake manifold, reference numeral 2 indicates a carburetor with a throttle valve 3 attached to the intake manifold 1, and reference numeral 4 indicates a breaker with a breaker arm 5. Each distributor is shown as having a plate 6, and the breaker plate 6 in the distributor 4 is provided with a first negative pressure which advances the ignition timing by rotating the plate in the direction of arrow A. The advance mechanism 7 and the second negative pressure advance mechanism 8 are connected in series via a rod 9.

Both of the negative pressure advance mechanisms 7 and 8 are configured such that a first diaphragm case 12 and a second diaphragm case 13 each having a diaphragm 10 and 11 are directly connected via a partition plate 14. The diaphragm 11 inside the case 13 has
The main spring 16 in the second negative pressure chamber 15
A connecting piece 17 is provided which presses into contact with the breaker plate 6, and fixes the rod 9 from the breaker plate 6 to the diaphragm 10 in the first diaphragm case 12, and also penetrates the first negative pressure chamber 18 to connect the connecting piece 17. 17, an auxiliary spring 20 is provided between the diaphragm 10 and the connecting piece 17, and a play of an appropriate distance S2 is provided between the collar 19 and the inner part of the connecting piece 17 in the advancing direction of the rod 9. On the other hand, a stopper piece 21 is provided in the second negative pressure chamber 15 at an appropriate distance S1 from the back surface of the diaphragm 11.

The first negative pressure advance mechanism 7
A third negative pressure advance mechanism 25 from a negative pressure port 23 provided downstream of the throttle valve 3 in the carburetor 2 is connected to the negative pressure chamber 18 , and a third negative pressure advance mechanism 25 is connected to the second negative pressure advance mechanism 8 in the second negative pressure advance mechanism 8 . 15, a negative pressure port 22 provided downstream of the throttle valve 3 in the carburetor 2;
The second negative pressure passages 31 connected to the first negative pressure passages 24 are connected to each other.

A first electromagnetic three-way switching valve 27 is provided in the third negative pressure transmission passage 25 between it and an atmospheric communication part 26 such as an intake air cleaner (not shown). , the first switching valve 27 is connected to a knocking center 28 provided in the engine (not shown) via a control circuit 29, and the first switching valve 27 is connected to the vacuum tank 3 in the second negative pressure chamber 15 when there is no knocking in the engine.
6, the third negative pressure transmission passage 2
However, when knocking occurs in the engine, the second negative pressure chamber 15 is switched to communicate with the atmosphere.

Further, a second negative pressure transmission passage 31 communicating with the first negative pressure chamber 18 and a fourth negative pressure transmission passage communicating with an advance port 30 provided slightly upstream of the closed position (idle opening degree) of the throttle valve 3 are provided. aisle 40
A second electromagnetic three-way switching valve 32 is provided at the connection between the first negative pressure transmission passage 24 and the negative pressure port 22 downstream of the throttle valve. Electric circuit 3 that connects
4 is provided with a switch 35 related to the opening degree of the throttle valve 3, and when the throttle valve 3 is at a low opening degree or an opening degree below the advance port 30, the first negative pressure transmission passage 24 and the second negative pressure transmission passage 31, and at other opening degrees, the second negative pressure transmission passage 31 and the fourth negative pressure transmission passage 40 are switched to communicate with each other.

Further, the first switching valve 27 is set to the switch 35 for the closed position of the throttle valve 3, so that when the throttle valve 3 reaches a low opening degree or an opening degree below that of the advance port 30, A switching valve 27 is configured to switch the second negative pressure chamber 15 into communication with the atmosphere.

The third negative pressure transmission passage 25 is provided with a negative pressure holding means 39 that includes a closed vacuum tank 36, a check valve 37, and a throttle orifice 38.

In this configuration, the opening degree of the throttle valve 3 is
When the throttle valve 3 has an opening degree larger than the position where the throttle valve 3 is applied to the advance port 30, the second switching valve 3
2 communicates the second negative pressure transmission passage 31 and the fourth negative pressure transmission passage 40, and the second negative pressure chamber 15 in the second negative pressure advance mechanism 8 includes an advance port 30.
The negative pressure generated at the fourth negative pressure transmission passage 40
and acts via the second negative pressure transmission passage 31. At the same time, the intake negative pressure downstream of the throttle valve 3 acts on the first negative pressure chamber 18 in the first negative pressure advance mechanism 7 via the third negative pressure transmission passage 25, so that the ignition timing is Advance angle control is performed by both the second negative pressure advance mechanism 8 and the first negative pressure advance mechanism 7.

In this operating state, when knocking occurs in the engine, the second negative pressure chamber 15 in the second negative pressure advance mechanism 8 is communicated with the atmosphere by the operation of the first switching valve 27, and the second negative pressure advance mechanism Since the advance effect by 8 is canceled, the ignition timing at the time of knocking is retarded by the amount advanced by the second negative pressure advance mechanism 8, thereby suppressing knocking. The retard control of the ignition timing during this knocking is performed by the second negative pressure advance mechanism 8, while at this time also the first negative pressure advance mechanism 7 The advanced angle is maintained in accordance with the negative pressure generated.

Next, in the idling operating range where the throttle valve 3 is approximately fully closed, the advance port 30 is on the upstream side of the throttle valve 3, while the second switching valve 32 in the second negative pressure transmission passage 31 is in the ON position of the switch 35. , the first negative pressure transmission passage 24 and the third negative pressure transmission passage 3
1, the first negative pressure chamber 18 in the first negative pressure advance mechanism is connected to the negative pressure port 22, and at the same time, the first switching valve 27 connects the second negative pressure chamber 15 to the atmosphere. Therefore, the ignition timing during idling is maintained at an ignition timing suitable for idling operation only by the first negative pressure advance mechanism 7.

In a low load state where the throttle valve 3 is applied to the advance port 30, the second negative pressure transmission passage 31 and the fourth negative pressure transmission passage 40 communicate with each other at the second switching valve 32, and In this state, negative pressure is generated at the 30 advance ports, and this negative pressure acts on the first negative pressure chamber 18 in the first negative pressure advance mechanism 7, so that the first negative pressure advance mechanism 7 At the same time, the first switching valve 27 is switched to apply the negative pressure in the vacuum tank 36 to the second negative pressure chamber 15, so that the ignition timing in the partial load operating range is the same as the ignition timing during idling. The amount of advance by the second negative pressure advance mechanism 8 is added to the timing, and the ignition timing is controlled to be appropriate for the part load operating range.

In this way, if the purpose is simply to advance the ignition timing in the partial load operating range when the throttle valve 3 is connected to the advance port 30 compared to the idling operation, the second switching valve 32 is used. Therefore, it is considered that there is no need to switch the first negative pressure chamber 18 from communicating with the negative pressure port 22 to communicating with the advance port 30.

However, in this partial load operating range, the intake negative pressure at the negative pressure port 22 downstream of the throttle valve 3 is large toward the vacuum side, and the negative pressure advance mechanism in the distributor 4 has no initial setting. Since an advance value of about 5 degrees is given, not only the second negative pressure advance mechanism 8 but also the first negative pressure advance mechanism 7
Also, related to the intake negative pressure downstream of the throttle valve 3, the ignition timing in the partial load operating range is overadvanced than the appropriate ignition timing for the part load operating range, resulting in frequent knocking. It turns out.

In contrast, in the present invention, when the partial low-load operation region is reached as described above, the first negative pressure chamber 18 in the first negative pressure advance mechanism 7 is connected from the negative pressure port 22 to the advance port 30. Since the negative pressure at the advance port 30 is smaller on the atmosphere side than the intake negative pressure at the negative pressure port 22 downstream of the throttle valve 3, the The amount of advance due to negative pressure is smaller than when the first negative pressure advance mechanism 7 is connected to the negative pressure port 22 downstream of the throttle valve 3, and the ignition timing in the partial load operating range is overadvanced. In other words, the ignition timing can be controlled to the appropriate ignition timing in a state where knocking does not occur.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the negative pressure advance mechanism in FIG. 1. DESCRIPTION OF SYMBOLS 1... Intake manifold, 3... Throttle valve, 4... Distributor, 7... First negative pressure advance mechanism, 8... Second negative pressure advance mechanism, 15... Second negative pressure chamber, 18...first negative pressure chamber, 22, 23...
Negative pressure port, 24... first negative pressure transmission passage, 31...
...Second negative pressure transmission passage, 25...Third negative pressure transmission passage, 40...Fourth negative pressure transmission passage, 27...First switching valve, 29...Knotting sensor, 30...Advance port, 32 ...Second switching valve, 35...
Throttle valve close position switch.

Claims (1)

[Scope of utility model registration request] The distributor includes a first negative pressure advance mechanism that advances the ignition timing in relation to the intake negative pressure downstream of the throttle valve, and a first negative pressure advance mechanism that advances the ignition timing in relation to the intake negative pressure downstream of the throttle valve. A second negative pressure advance mechanism is provided in series to control the advance angle, and a negative pressure transmission passage connects a second negative pressure chamber in the second negative pressure advance mechanism to a downstream side of the throttle valve. During operation, the second negative pressure chamber is switched to communicate with the atmosphere in response to a knocking signal from a knocking sensor provided in the engine, and the second negative pressure chamber is switched to communicate with the atmosphere in response to a closing signal from the throttle valve. A first switching valve is provided which switches the chamber to communicate with the atmosphere, and an advance port and an advance port are provided, in which the first negative pressure chamber in the first negative pressure advance mechanism is provided slightly upstream from the closed position of the throttle valve. When there is no closing signal from the throttle valve in the negative pressure transmission passage connected to the negative pressure port downstream from the throttle valve, the first negative pressure chamber is communicated only to the advance port, but when the closing signal from the throttle valve 1. An ignition timing control device for an internal combustion engine, characterized in that a second switching valve is provided that switches the first negative pressure chamber to communicate only with the negative pressure port in response to the change in pressure.