JPS5823502B2 - Ninenkikannokoudohoshiyousouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an altitude compensating device for an internal combustion engine that compensates for deterioration in drivability of the internal combustion engine due to changes in atmospheric pressure due to altitude.

Conventionally, in systems where the power piston of the power system is operated by manifold negative pressure, the manifold negative pressure decreases with altitude (see the solid line in Figure 1).
Therefore, even if the vehicle is operated at the same time, the higher the altitude, the more frequent the power operation becomes, which has the drawback of increasing harmful exhaust gas and deteriorating fuel efficiency.

In addition, the negative pressure advance angle of the distributor is similarly controlled by guiding the negative pressure of the manifold to the negative pressure advance diaphragm chamber of the distributor and controlling it by the movement of this diaphragm, so even if the same operation is performed, the altitude As the pressure increases, the manifold negative pressure decreases (see the solid line in Figure 1).
, the amount of displacement of the diaphragm decreases, and the ignition timing becomes delayed compared to the level condition.

On the other hand, when the same operation is performed, the required ignition timing is almost the same as on flat ground because the intake air filling efficiency is almost constant, so proper ignition is not performed and engine operability deteriorates, resulting in harmful This results in an increase in exhaust emissions of 1-xv and a deterioration in fuel efficiency.

The present invention has been made to improve these drawbacks, and an object of the present invention is to provide an altitude compensation device for an internal combustion engine that can provide power operation and negative pressure advance characteristics that are not affected by altitude.

The altitude compensator for an internal combustion engine according to the present invention communicates the negative pressure in the intake passage to the power piston chamber of the power mechanism via the negative chamber, and communicates the negative chamber to the atmosphere by a valve device when the atmospheric pressure is not low. In addition, when the atmospheric pressure is low, the negative royal circuit is isolated from the atmosphere, thereby eliminating the influence of atmospheric pressure on the power mechanism, and the negative pressure advance diaphragm device of the distributor is also communicated with the negative royal bank when the atmospheric pressure is not idling. to eliminate the influence of atmospheric pressure on the diaphragm device for negative pressure advance, and when idling, the switching valve 1 isolates the diaphragm device from the negative pressure chamber, and communicates the diaphragm device to the atmosphere to prevent overadvance during idling. In addition, the negative pressure chamber absorbs negative pressure fluctuations in the intake passage, thereby stabilizing the operation of the power mechanism and the negative pressure advancing diaphragm device.

In this way, when introducing atmospheric pressure appropriately into the power piston chamber of the power mechanism and the negative pressure advance diaphragm device of the distributor, the power spring and diaphragm spring are weakened compared to the conventional example, and the power on flat ground is reduced. The mechanism and the operation of the negative pressure advance diaphragm device should be the same as in the prior art.

The present invention will be explained below based on the embodiment shown in FIG.

The carburetor main body 1 includes an intake passage 3 having a bench area 2, and a main jet 4 and a main nozzle 4A in this intake passage 3.
The main nozzle 4A is provided with a float chamber 5 that stores fuel supplied through the main nozzle 4A, and a power mechanism 6 that supplies extra fuel to the main nozzle 4A during high output.

This power mechanism 6 includes a valve chamber 8 having an opening 8A in a passage 7 communicating with a main nozzle 4A, a poppet whose large diameter portion is housed in the valve chamber 8, and whose other end protrudes from the valve chamber 8. A power valve 9, a compression spring 11 interposed between a spring receiver 10 fixed to the other end of the power valve 9 and the valve chamber 8, and a power piston chamber 12 integrally formed in the upper part of the float chamber 5. , a power piston 13 housed in the power piston chamber 12, a piston rod 14 protruding from one end of the power piston 13 and abutting the spring receiver 10 from above, and the other end of the power piston 13 and the power piston. It is constituted by a power spring 15 that is interposed between the earthen wall of the chamber 12 and urges the power piston 13 downward.

A throttle valve 16 is rotatably provided within the intake passage 3.

A negative crown 18 having a passage 17 communicating with the intake passage 3G is provided in the carburetor main body 1 at a downstream position of the throttle valve 16.

This negative chamber 18 is communicated with the atmosphere through an opening 19,
A valve device 20 is provided opposite to this frontage 19 .

This valve device 20 is comprised of a bellows 21 whose interior is substantially evacuated, and a needle valve 22 which is fixed to the tip of the bellows 21 and has its tip opposed to the opening 19.

Further, this valve device 20 is actuated by changes in atmospheric pressure, and the lower the atmospheric pressure is, the smaller the opening area of the opening 19 is.

The negative royal chamber 18 is connected to the power piston chamber 12 of the power mechanism 6 via a negative pressure introduction path 23, and is connected to the negative pressure advance diaphragm device 26 of the distributor 25 via a negative pressure introduction path 24. It is connected to the diaphragm chamber 27.

A switching valve 2B is interposed in the middle of the negative pressure introduction path 24,
With this switching valve 28, the negative pressure introducing section 24 is connected to the negative pressure chamber 1B.
Alternatively, it can be switched to communicate with the atmosphere inlet 29 which communicates with the atmosphere.

The switching valve 28 is fixed to a rod 32 fixed to a diaphragm 31 of a diaphragm device 30 provided on one side of the carburetor main body 1, and is operated according to the movement of the diaphragm 31.

Inside the diaphragm chamber 33 of this diaphragm device 30, a rod 32 is inserted so as to move the diaphragm 31 upward in the figure, that is, in a direction that blocks communication of the negative pressure introduction path 24 with the negative pressure chamber 18.
A compression spring 34 is interposed to bias the switching valve 28 via the compressor.

Further, the diaphragm chamber 33 communicates with a vacuum advance port 35 opened in the intake passage 3 via a passage 36.

This vacuum advance port 35 is located upstream of the throttle valve 16 when the engine is idling, and is located upstream of the throttle valve 16 when the engine is idling.
6 is provided in the intake passage 3 at a location downstream of the intake passage 6.

Furthermore, a communication hole 38 communicating with the atmosphere is bored in a chamber 37 of the diaphragm device 30 on the opposite side from the diaphragm chamber 33.

In addition, the reference numeral 39 in the figure is a diaphragm of the negative pressure advance diaphragm device 26 of the IJ computer 25, the reference numeral 4
0 indicates a compression spring that always biases the diaphragm 39 in the direction in which the rod 41 integral with the diaphragm 39 protrudes.

Next, the operation of this embodiment will be explained.

When traveling on flat ground, as shown by the solid line in FIG. 1, the manifold negative pressure is high, and therefore the negative pressure acting on the negative pressure chamber 18 is also low.

On the other hand, the bellows 21 of the valve device 20 is contracted due to the high atmospheric pressure, and the opening area of the opening 19 of the negative pressure chamber 18 is large, and the amount of air flowing into the negative pressure chamber 18 is large. The pressure is lowered, and the negative pressure in the negative chamber 18 is finally given the pressure shown by the broken line in FIG.

This negative pressure is transmitted to the power mechanism 6 through the negative pressure introduction passages 23 and 24.
power piston chamber 12 and distributor 25
diaphragm chamber 2 of the negative pressure advance diaphragm device 26
7.

At this time, it is assumed that the switching valve 28 does not cut off communication with the negative royal chamber 18.

Next, as the altitude gradually increases, the manifold negative pressure decreases along the solid line in FIG. reduce

Therefore, the negative pressure in the negative pressure chamber 18 is balanced by the decreasing manifold negative pressure and the decrease in the amount of atmospheric air inflow.

It always shows a constant value (see broken line in Figure 1).

In this way, since the negative pressure in the negative royal chamber 18 is maintained constant,
The operation of the power piston 13 of the power mechanism 6 and the operation of the diaphragm 39 of the diaphragm device 26 of the distributor 25 are always constant and do not deteriorate driveability.

Next, the functions of the switching valve 28 and the diaphragm device 30 will be explained.

During idling, the throttle valve 16 is in the almost closed state shown in the figure, and is in a vacuum state.

- The advance port 35 is located upstream of the throttle valve 16.

Therefore, the negative pressure in the port 35 is low, and the diaphragm 31 of the diaphragm device 30 is pushed upward by the action of the compression spring 34, and the port is fixed to the diaphragm 31.

The switching valve 28 is also pushed up via the rad 32, allowing the negative pressure introduction path 24 to communicate with the atmosphere.

The atmosphere communicated with this negative pressure introduction path 24 acts on the diaphragm device 26 of the distributor 25, so that the negative pressure of the distributor 25 is not advanced.

Then, when the off-idle state is reached, the throttle valve 16 is opened and the vacuum advance port 35 is opened.
Located downstream of the throttle valve 16 , manifold negative pressure acts on the port 35 to pull down the diaphragm 31 of the diaphragm device 30 against the compression spring 34 .

As the diaphragm 31 descends, the switching valve 28 is switched and the communication to the atmospheric air inlet 29 is cut off, and the negative pressure in the negative royal chamber 18 acts on the diaphragm device 26 of the distributor 25, causing a predetermined negative pressure advance angle. is obtained.

By repeating such a series of operations (this is to compensate for the rise of the negative pressure advance angle).

In addition, in implementation, the valve device 20 is not limited to the bellows 21 but may be any device that operates in response to changes in atmospheric pressure, and the switching valve 28 is not limited to one that is fixed to the rod 32 fixed to the diaphragm 31. Any device that is linked to the movement of the diaphragm 31 may be used.

Furthermore, the negative pressure chamber 18 is not limited to being integrated with the carburetor main body 1, but may be provided separately.

As described above, the present invention operates the power mechanism and the diaphragm device for advancing the negative pressure of the disk I-IJ computer by the negative pressure in the negative royal chamber provided in the carburetor, and has an opening communicating with the atmosphere in the negative royal chamber. At the same time, the opening area of this opening is reduced as the atmospheric pressure decreases using a valve device that operates based on changes in atmospheric pressure, which prevents the power mechanism from operating quickly even at high altitudes, resulting in an increase in harmful exhaust gases.
It can prevent deterioration of fuel efficiency, and the negative pressure advance angle of the distributor is performed appropriately, which improves engine drivability and has remarkable effects such as preventing an increase in harmful exhaust gas and deterioration of fuel efficiency. In addition, a switching valve having an atmospheric air inlet is provided in the negative pressure introduction path from the negative royal block to the negative pressure advance diaphragm device of the distributor, and this switching valve is operated by the negative pressure applied to the port provided on the wall of the intake passage. This is because it is activated by the tire phragm device that operates, so that the negative royal chamber and the diaphragm chamber of the diaphragm device for negative pressure advancement of the distributor communicate with each other only when the negative pressure applied to the port is higher than a predetermined value. The ignition timing can be maintained properly during idle and off-idle, and at least the conventional switching of negative pressure advance during idle and off-idle can be maintained.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram showing the relationship between altitude and manifold negative pressure, and FIG. 2 is a sectional view showing the main parts of an altitude compensating device for an internal combustion engine according to the present invention. 1... Carburetor body, 3... Intake passage,
6... Power mechanism, 12... Power piston chamber, 17... Passage, 18... Negative pressure chamber, 19... Opening, 20... Valve device, 23, 24... Negative pressure introduction path, 25...
- De-istoripulator, 26...Diaphragm device, 27...Diaphragm chamber, 28...
...Switching valve, 29...Atmospheric inlet, 30...
...Diaphragm device, 35...Vacuum advance port, 36...Passway.

Claims (1)

[Claims] 1. A negative royal circuit that communicates with the downstream side of the throttle valve in the intake passage, a diaphragm device that communicates with the upstream side of the throttle valve in the idle state and the downstream side of the throttle valve in the off-idle state, and this diaphragm device. a switching valve connected to the device, which communicates a negative pressure advance diaphragm device of the distributor with the atmosphere when idle, and communicates a negative pressure advance dash diaphragm device of the distributor with the negative pressure source at other times; and a valve device that communicates the negative royal chamber with the atmosphere when the atmospheric pressure is not low and shuts off the negative royal house from the atmosphere when the atmospheric pressure is low, and a power piston chamber of the power mechanism is communicated with the negative royal house. Engine altitude compensator.