JPS6228697Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an ignition timing control device.

Conventionally, in internal combustion engines for automobiles, etc., there has been a technical philosophy of slightly advancing the ignition timing during idling, within a range that does not cause instability in engine combustion, in order to improve fuel efficiency during idling. An ignition timing control device as shown in FIG. 1 has already been proposed. That is, in this conventional device, the pressure responsive device 2 has a first diaphragm 8 and a second diaphragm 8 that partition the first pressure chamber 4 from the second pressure chamber 6.
a second diaphragm 10 that separates the pressure chamber 6 from the atmosphere;
An advance angle rod 12 is fixed to the second diaphragm 10, and the first diaphragm 8 engages with the second diaphragm 10 only when moving upward via the coupling mechanism 14. Further, the first pressure chamber 4 has a port 20 formed in the intake passage wall slightly upstream from the fully closed position of the throttle valve 18 and near the upstream free end of the throttle valve 18. Intake pressure is conducted to the second pressure chamber 6 at a position slightly downstream of the fully closed position of the throttle valve 18 and at the second pressure chamber 6.
The structure is configured such that the intake pressure generated in the port 22 bored in the wall of the intake passage near the free end on the downstream side of the diaphragm 8 is conducted, and when idling, the negative pressure generated in the port 22 causes the second diaphragm 10 to move upward. During normal driving, the first diaphragm 8 is urged upward by the negative pressure generated at the port 20, and the ignition timing is advanced via the second diaphragm 10. be. However, according to this device, the second diaphragm 1
0 operates by constantly engaging with the advance angle rod 12, so it must be relatively large and strong in consideration of durability, and also during normal driving due to the movement of the first diaphragm 8. The amount of advance during idling must be larger than the amount of advance during idling due to movement of only the second diaphragm 10, so the first diaphragm 8 must also be sized (pressure-receiving area ), and the overall size of the device was unavoidable.

This invention was proposed in view of the above, and
First and second pressure chambers are formed in the pressure response device and partitioned by a first movable partition, the second pressure chamber is separated from the atmosphere, and the pressure receiving area is larger than that of the first movable partition. a second movable bulkhead; an advance angle that is attached to the second movable bulkhead and operates the breaker plate of the distributor to the advance side when the second movable bulkhead moves toward the second pressure chamber; rod, the first movable bulkhead is removably connected to the second movable bulkhead or the advance angle rod, and when the first movable bulkhead moves toward the first pressure chamber. a connecting means for engaging the first movable bulkhead with the second movable bulkhead or the advance rod to drive the advance rod in the advance direction; one end communicating with the first pressure chamber and the other end communicating with the first pressure chamber; A first pressure passage communicates with a port bored in the wall of the intake passage downstream of the throttle valve fully closed position of the engine, one end communicating with the second pressure chamber and the other end communicating with the throttle valve fully closed position. An ignition timing control device characterized by comprising a second pressure conduit passage connected to a port bored in the intake passage wall slightly upstream of the throttle valve and near the upstream free end of the throttle valve. This is a summary.

According to the present invention, since the advance angle rod is attached and the second diaphragm that controls the advance angle during normal running is formed in a large size, durability and sufficient advance angle during normal running are ensured. Since the first diaphragm that controls the advance angle during idling is formed in a small size, the entire device can be made compact and inexpensive.

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

In FIG. 2, a pressure response device 30 for ignition timing control to which intake negative pressure generated in an intake passage 25 of an automobile engine 24 is connected has a first pressure chamber 3.
2 and a second pressure chamber 34 are formed, of which the first pressure chamber 32 is connected to the first pressure conduction path 26.
The second pressure chamber 34 is connected to a port (hereinafter referred to as F port) 28 which is bored slightly downstream of the fully closed position of the throttle valve 27 and near the free end of the throttle valve 27 on the downstream side. , a port (hereinafter referred to as D port) 31 is bored through the second pressure introduction path 29 slightly upstream of the fully closed position of the throttle valve 27 and near the upstream free end of the throttle valve 27.
is communicated with. Further, the first pressure chamber 32 is partitioned from the second pressure chamber 34 by a first diaphragm 36, which is a first movable partition wall, and
is a second diaphragm 38 which is a second movable bulkhead having a larger pressure receiving area than the first diaphragm 36;
It is separated from the atmosphere by An advance angle rod 40 connected to a breaker plate of a distributor (not shown) is attached to the second diaphragm 38, and when the second diaphragm 38 moves upward in FIG. The breaker plate is rotated so that the On the other hand, a rod 42 is attached to the first diaphragm 36.
A flange portion 46 is formed at the lower end of the diaphragm 38 and is detachable from a stopper portion 44 attached to the second diaphragm 38. This flange portion 46 is the first
When the diaphragm 36 moves upward in FIG. 2, it engages with the stopper portion 44 and acts to move the advance rod 40 upward via the second diaphragm 38. Further, 48 is a spring provided between the outer plate of the pressure responsive device 30 and the second diaphragm 38, and this spring 48 is connected to the second diaphragm 38, the stopper portion 44, and the rod 42.
The first diaphragm 36 is urged downward in FIG. The first and second diaphragms 36 and 38 are normally positioned at the lowest position in FIG. 2 by a stopper member 50 attached to the first diaphragm 36, and are subjected to an initial biasing force set by a spring 48. At this time, the advance angle rod 40 holds the first breaker plate at the position where the ignition advance amount is the smallest. Further, 52 is a stopper member that determines the uppermost position in FIG. 2 of the first diaphragm 36, and 54 is a stopper member that determines the uppermost position in FIG. 2 of the second diaphragm 38. The movable distance of the diaphragm 38 is determined by the stopper member 52.
The movable distance of the first diaphragm 36 is set as follows.

According to the above configuration, when the engine is operated in an idling state as shown by diagonal lines in FIG. D port 31 when located between
The intake pressure generated at the F port 28 becomes approximately atmospheric pressure as shown in FIG. 3a, while the intake pressure generated at the F port 28 becomes negative pressure as shown in FIG. 3b.
The second pressure chamber 34 has approximately atmospheric pressure, and the first pressure chamber 32
is a negative pressure, so that almost no biasing force due to the differential pressure acts on the second diaphragm 38, but a biasing force upward in FIG. 2 due to the differential pressure acts on the first diaphragm 36. Due to this upward biasing force, the first diaphragm 36 resists the biasing force of the spring 48 and is displaced upward in FIG. The rod 40 rotates a breaker plate (not shown) so that the amount of ignition advance increases. On the other hand, when the engine is operated in a normal torque generation state, that is, the throttle valve 2
7 is further rotated in the opening direction beyond the position where both ends thereof face both ports 31 and 28 and is held, the intake pressure generated at the F port 28 becomes approximately atmospheric pressure and is generated at the D port. Since the intake pressure becomes negative pressure, the first pressure chamber 32 is at approximately atmospheric pressure, and the second pressure chamber 34 is at negative pressure.
The diaphragm 36 is urged downward in FIG.
While located at the lowest position in the figure, the second diaphragm 38 resists the biasing force of the spring 48 and is displaced upward in the figure according to the magnitude of the negative pressure in the second pressure chamber 34, and the advance angle rod 40 A breaker plate (not shown) is rotated to increase the amount of ignition advance.
Therefore, during idling, the amount of ignition advance is increased in accordance with the negative pressure generated at the F port 28 to improve fuel efficiency, while during normal torque generating operation, the ignition advance is increased in accordance with the negative pressure generated at the D port 31. The advance amount is increased to improve fuel efficiency and increase output.

At this time, the amount of advance during idling is set by the urging force of the negative pressure acting on the first diaphragm 36, which has a small pressure-receiving area, and the urging force of the spring 48, and the amount of advance during normal torque-generating operation is determined by the pressure-receiving area. is set by the urging force of the negative pressure acting on the second diaphragm 38 and the urging force of the spring 48, and the first diaphragm 3
The maximum movement amount of the second diaphragm 38 is set relatively small by the stopper 52, and the maximum movement amount of the second diaphragm 38 is set relatively large by the stopper 54. Therefore, the advance angle amount during idling is as shown in FIG. As shown by the solid line, it increases slowly in response to an increase in the negative pressure generated at the F port 28, and its maximum value is small, so that it does not cause unstable combustion due to overadvance during idling. , and the advance angle amount during normal torque generation is as shown by the broken line in FIG.
As the negative pressure generated increases, the maximum value increases rapidly, and the fuel efficiency and output are sufficiently improved during normal torque generation.

Furthermore, since the second diaphragm 38, which operates by constantly engaging the advance angle rod 40, is large, durability is improved, while the first diaphragm 36 is small, so the entire pressure-responsive device 30 becomes compact.
Moreover, it has become possible to form it at low cost.

Furthermore, in this embodiment, one spring 4
8 to operate the first and second diaphragms, the pressure-responsive device 30 is further miniaturized and manufactured at low cost.

In the above embodiment, the first pressure chamber 32 is configured to conduct the intake pressure generated at the F port 28. However, when the engine is idling, the intake pressure generated at the F port 28 is connected to the first pressure chamber 32.
The intake pressure is approximately equal to the intake pressure generated at the D port 31 during normal torque generation, that is, the pressure generated in the intake passage (for example, the manifold) downstream of the throttle valve installation position. It is a good thing.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing a conventional example, Figure 2 is a sectional view showing an embodiment of the present invention, Figures 3a and b are characteristic diagrams of intake pressure of the engine according to the same embodiment, and Figure 4. is an ignition advance angle characteristic diagram in the same example. 25...Intake passage, 26...First pressure introduction passage, 27...Throttle valve, 28...F port,
29... Second pressure conduction path, 30... Pressure response device, 31... D port, 32... First negative pressure chamber,
34... Second negative pressure chamber, 36... First diaphragm, 38... Second diaphragm, 40... Advance angle rod, 42... Rod, 44... Stopper section.

Claims (1)

[Scope of utility model registration request] first and second pressure chambers formed in the pressure responsive device and partitioned by a first movable partition;
The second pressure chamber is separated from the atmosphere and the first pressure chamber is separated from the atmosphere.
The second movable partition wall has a larger pressure receiving area than the movable partition wall.
a movable bulkhead; an advance angle rod that is attached to the second movable bulkhead and operates a breaker plate of the distributor to the advance side when the second movable bulkhead moves toward the second pressure chamber; The first movable bulkhead is removably connected to the second movable bulkhead or the advance rod, and when the first movable bulkhead moves toward the first pressure chamber, A connecting means for engaging the first movable bulkhead with the second movable bulkhead or the advance rod to drive the advance rod in the advance side; one end communicates with the first pressure chamber and the other end communicates with the engine. a first pressure conduit passage communicating with a port bored in the intake passage wall on the downstream side of the throttle valve fully closed position;
One end communicates with the second pressure chamber, and the other end communicates with a port bored in the intake passage wall slightly upstream of the throttle valve's fully closed position and near the upstream free end of the throttle valve. An ignition timing control device comprising a second pressure conduit.