JPS6235900Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an engine ignition system that controls the operating state of the engine by controlling a distributor using a double diaphragm device. It is.

(Prior art) Conventionally, a double diaphragm device is used to control a distributor that sets the ignition advance angle of the engine, and the ignition advance angle is controlled in multiple stages according to the intake negative pressure. Ignition devices are known (see Japanese Patent Laid-Open No. 53-43042).

In this double diaphragm device, the internal negative pressure chamber is partitioned into a first chamber and a second chamber by first and second diaphragms, and the first diaphragm and the second diaphragm have a pressure equal to or greater than a predetermined amount of the second diaphragm. It has a basic structure connected by a regulating member that regulates displacement.

In controlling the ignition advance angle using this double diaphragm device, the intake negative pressure is divided into three regions: high, medium, and low, and at high intake negative pressure, the additive displacement of the first and second diaphragms is used. Then, a large ignition advance amount (θ ₁ + θ ₂ ) is set, and in the intermediate range, as the intake negative pressure decreases, the first diaphragm gradually returns to its position, and eventually corresponds to the displacement of only the second diaphragm. When the ignition advance amount θ ₂ is set and the intake pressure becomes low near atmospheric pressure, the second diaphragm is also returned to its position and control is performed such that the ignition advance amount becomes zero.

In the above control, the reason why the ignition advance amount is set to zero at high loads that reach negative intake pressure close to atmospheric pressure is because when the outside temperature is low, such as in winter, the density of the intake air increases and the actual charging amount increases. However, if the ignition advance amount is maintained at the above-mentioned ignition advance amount _θ2 , knocking may occur.

However, with this control method, in the summer when the outside temperature is high, the charging efficiency decreases, and although knocking does not occur even if the ignition advance amount is not zero, the ignition advance amount actually increases. It becomes zero under load, which is disadvantageous for engine output.

To prevent engine output loss, when the outside temperature is high, the intake negative pressure in the second chamber, which is involved in the displacement of the second diaphragm, is reduced to the second chamber when the intake negative pressure transitions from medium to low. It is conceivable to keep the second diaphragm in a displaced state by sealing it, but at this stage the intake negative pressure has decreased considerably, and with that level of intake negative pressure, the second diaphragm
It is practically impossible to maintain the diaphragm in a displaced state, and the ignition advance amount eventually becomes zero.

SUMMARY OF THE DISCLOSURE An object of the present invention is to provide an engine ignition device that is capable of controlling the amount of ignition advance during high-load operation in response to the level of outside air temperature.

(Structure of the invention) Therefore, the present invention targets an ignition system for an engine equipped with the above-mentioned double diaphragm device,
The present invention is characterized in that a control means is provided for controlling the intake negative pressure applied to the second diaphragm in accordance with the intake negative pressure and the intake air temperature (outside air temperature).

That is, in the present invention, the negative pressure chamber of the double diaphragm device is divided into the first and second negative pressure chambers by the first and second diaphragms.
Among the chamber partitions and the first and second negative pressure conduit passages that introduce negative intake pressure into the first and second chambers, respectively, the first passage introduces intake negative pressure into the second chamber that is involved in the displacement of the second diaphragm. The second negative pressure conduit is provided with a control valve that closes the second negative pressure conduit when the intake air temperature (outside temperature) is above a set value and the intake negative pressure is below a set value.

In other words, in summer when the intake temperature is high,
When the intake negative pressure drops below a certain level, the second negative pressure conduit is closed to seal the intake negative pressure in the second chamber, and when the engine shifts to high-load operation and the intake negative pressure drops to near atmospheric pressure. Also, the second diaphragm is maintained in a displaced state to ensure a constant advance angle amount.

On the other hand, in winter when the intake temperature is low,
Since the second negative pressure conduit is not closed by the control valve, during high-load operation of the engine when the intake negative pressure approaches atmospheric pressure, the second diaphragm returns to its position as the intake negative pressure decreases. The advance angle is retarded to accommodate an increase in the filling amount.

(Effect of the invention) Therefore, according to the invention, the ignition advance angle can be retarded to prevent knocking during high-load operation in winter or in cold regions, and it is possible to retard the ignition advance angle during high-load operation in summer or in warm regions. Sometimes, the ignition advance angle can be advanced to be advantageous for improving the output performance of the engine.

(Example) Hereinafter, embodiments of the present invention will be described in detail.

As shown in FIG. 1, for the distributor 1 that determines the ignition timing of the engine,
An actuating rod 2 is provided which is linked to a movable breaker plate of the distributor 1, and the proximal end of the actuating rod 2 is supported on a double diaphragm device 3.
Control its operation.

This double diaphragm device 3 has a conventionally known structure, and includes first and second casings 5 and 6, respectively, which are superposed to form one casing 4 as a whole. Diaphragm 7, 8
The inside of the casing 4 is divided into the first, second and third
a first diaphragm 7 and a first casing 5;
The chamber 9 and the second chamber 10 defined between the first and second diaphragms 7 and 8 are negative pressure chambers, and the third chamber 11 defined by the second diaphragm 8 and the second casing 6 is a negative pressure chamber. An opening 12 in the second casing 6 for connecting the actuating rod 2 to the second diaphragm 8 forms an atmospheric chamber open to the atmosphere.

The first and second chambers 9 and 10 as the negative pressure chambers are provided with two common negative pressure conduit passages 16 having a negative pressure outlet 15 downstream of the throttle valve 14 provided in the intake passage 13 of the engine. The throttle valve 14 is
It is designed to introduce negative intake pressure downstream.

The first diaphragm 7 resists the spring force of the first coil spring 19 compressed in the first chamber 9 when the intake negative pressure introduced is a high negative pressure, for example, (-300) mmHg or more. It is displaced until it abuts against the stopper bolt 20 that is supported by protruding from the first casing 5 toward the first diaphragm 7, and by that displacement, the distributor 1 is advanced by θ _1. Corner (see Figure 2).

On the other hand, the second diaphragm 8 is always urged by a second coil spring 21 compressed in the second chamber 10, and the first diaphragm 6 has a stroke d with respect to the first diaphragm 7. They are connected via a stroke regulating member 22 that allows for independent displacement within a range. The set load of the second coil spring 21 is set one step smaller than the set load of the first coil spring 19, so that the intake negative pressure is, for example, (-150).
mmHg or less and the first diaphragm 7 is not displaced (returning), the second diaphragm 8 moves relative to the first diaphragm 7 to maintain the stroke d allowed by the stroke regulating member 22. displacement. By the displacement of the second diaphragm 8 by the stroke d, the distributor 1 is advanced by θ ₂ (the second
(see figure).

Note that the stopper in the return direction of the first and second diaphragms 7 and 8 is a stopper that moves the stroke regulating member 22 to the first position.
Mounting plate 2 for fixing to diaphragm 7
a mounting plate 24 for coupling the actuating rod 2 to the rising edge of the outer periphery of the diaphragm 3 and the second diaphragm 8;
It is formed by the rising edge of the outer periphery.

On the other hand, an electromagnetically actuated control valve 25 for opening and closing the passage 18 is interposed in the middle of the second negative pressure conduit 18 that introduces the intake negative pressure into the second chamber 10 that is involved in the displacement of the second diaphragm 8. do.

A control circuit 26 that controls turning on and off of this control valve 25 includes, for example, a vacuum switch 27 that is turned on when the intake negative pressure falls below (-210) mmHg (when it shifts to the atmospheric side), and an outside temperature The AND gate 29 consists of an outside temperature switch 28 that is turned on when the temperature is higher than the set temperature T°C, and an AND gate 29 which uses the ON and OFF signals of the vacuum switch 27 and the outside temperature switch 28 as both input signals. When the output is high, that is, when the intake negative pressure is below (-210) mmHg and the outside temperature is above T°C, the control valve 25 is closed and the second negative pressure passage 18 is closed.
(-210) mm into the second chamber 10.
Seal inspiratory negative pressure close to Hg. This set negative pressure is set to a value sufficiently larger than the intake negative pressure (-70) mmHg when the second diaphragm 8 is returned to its position by the spring force of the second coil spring 20, so the intake negative pressure is (-70) mmHg, even during high-load operation, the second diaphragm 8
Stroke d due to intake negative pressure sealed within 0
The advance angle amount of the distributor 1 is maintained at a constant advance angle amount θ ₂ commensurate with the stroke d, as shown by arrow A in FIG.

On the other hand, under conditions other than the above, that is, when the outside temperature is as low as T°C, even if the intake negative pressure drops below (-210) mmHg, the output of the AND gate 29 does not become “high” and the control valve 24 Since it is held in the open state and the second negative pressure conduit 18 is not interrupted midway,
The current intake negative pressure is directly introduced into the second chamber 10. As a result, when the intake negative pressure decreases to below (-70) mmHg, as shown by arrow B in FIG. The second diaphragm 8 is returned to its position by overcoming the intake negative pressure, and the amount of advance becomes zero.

That is, according to the double diaphragm device according to the present invention, when the outside temperature (intake temperature) is low, the ignition advance angle is adjusted to prevent knocking that may occur during high-load operation as the filling rate increases. The engine output can be improved by advancing the engine if knocking does not occur during high-load operation even if the engine is advanced when the outside temperature is high.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view of the main parts of an engine ignition system according to an embodiment of the present invention, and FIG. 2 is a graph showing a method of setting an advance angle obtained by the embodiment. DESCRIPTION OF SYMBOLS 1... Distributor, 2... Operating rod, 3... Double diaphragm device, 7, 8... First, second diaphragm, 9, 10... First, second
Chamber, 13... Intake passage, 16, 17... First and second negative pressure conduit passages, 22... Stroke regulating member, 2
5... Control valve, 26... Control circuit, 27... Vacuum switch, 28... Outside temperature switch.

Claims (1)

[Claims for Utility Model Registration] In an engine ignition system in which a distributor is controlled by a double diaphragm device, the negative pressure chamber of the double diaphragm device is connected to the first and second chambers by the first and second diaphragms. a second diaphragm is connected to the actuating rod of the distributor, the first diaphragm is provided with a regulating member for regulating movement of the second diaphragm beyond a certain amount, and a second chamber is formed between the first and second diaphragms. and the first chamber adjacent to the second chamber, which introduces negative intake pressure into the first chamber, respectively.
An engine characterized in that a negative pressure conduit is provided, and the second negative pressure conduit is provided with a control valve that closes the second negative pressure conduit when the intake air temperature is above a set value and the intake negative pressure is below the set value. igniter.