JPS586096B2 - Exhaust purification device for vehicles with automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for eliminating shift shock and purifying exhaust gas in a vehicle with an automatic transmission by eliminating unnecessary gear changes when the accelerator is released after acceleration.

Shift operation of an automatic transmission. The load acting on the engine is detected as throttle pressure via engine suction negative pressure, and the vehicle speed is detected as governor pressure. Both pressures and line pressure are applied to the lift valve to automatically shift gears. A device for
The speed change characteristics in the drive range (D range) of this device are as shown in FIG.

In the figure, numbers indicate gear stages, and arrows indicate gear shift operation directions.

Now, when accelerating with a conventional automatic transmission, the engine suction negative pressure decreases (approaches atmospheric pressure), but the throttle pressure increases due to the action of the vacuum throttle valve, and this throttle pressure is transferred to the pressure regulator. While acting on the valve to increase the line pressure, governor pressure in accordance with the vehicle speed acts on the lift valve.

Then, the gear is automatically shifted to the false range and the shift from D1 to D2 is completed (point A in FIG. 1).

After that, when the accelerator pedal is released, the suction negative pressure increases and the throttle pressure decreases accordingly, resulting in an automatic shift to the D3 range (top driving range) as shown in FIG. 1B.

In such a case, in order to accelerate again, the vehicle will be accelerated in the D3 range, so the accelerator pedal must be depressed more than necessary, and the amount of harmful exhaust components, especially NOx, will increase.

Furthermore, depending on the depression of the accelerator pedal, the throttle pressure increases beyond the shift point to the D2 range (first
Figure C), or when performing a kickdown operation D2
<<D3> Shifts between the ranges are repeated, resulting in a shift shock and extremely poor drivability.

In the present invention, in view of such drawbacks, when the engine suction negative pressure increases rapidly, for example, as in the above example when the accelerator is released after acceleration,
In order to prevent the corresponding throttle pressure from decreasing suddenly,
Avoid immediately upshifting and shift to lower gears (e.g. D).
The purpose is to suppress an increase in the amount of harmful exhaust components emitted due to pressing the accelerator more than necessary by allowing the next acceleration operation to proceed with 2).

As a means for achieving this objective, the present invention provides a delay valve that delays pressure transmission when suction negative pressure increases rapidly, in the suction negative pressure passage that acts on the diaphragm device of the vacuum throttle valve to obtain throttle pressure corresponding to suction negative pressure. Interpose.

An example of the implementation of the present invention will be explained below based on FIG. 2.

In the figure, 1 is an air cleaner, 2 is a carburetor, and includes a choke valve 3, a fuel nozzle 4, a slot valve 5, and an intake passage 6, 7 is an intake manifold, and 8 is an engine.

A vacuum throttle valve 10 includes a vacuum control diaphragm device 71 (hereinafter simply referred to as a diaphragm device) and a valve section 12.

The diaphragm device 11 is defined by a diaphragm 13 into a negative pressure chamber 15 in which a spring 14 is inserted and an atmospheric chamber 16. The negative pressure chamber 15 is connected to a negative pressure passage 21 via a delay valve 20.
This introduces negative suction pressure within the intake manifold 7.

Diaphragm 13 is connected to spool 18 via rod 17.

The Subur 18 has a first land 18a and a second land 18b, an oil passage 31 for throttle pressure Pt whose opening/closing or passage area is controlled by the lands 18a and 18b, an oil passage 32 for line pressure P1, and a drain drain. A passage 33 is provided, and the throttle pressure Pt oil passage 31 is arranged such that one end thereof is guided to the valve cylinder 19.

Both the throttle pressure Pt and the governor pressure Pg depending on the vehicle speed act on the shift valve 34 to perform a gear shifting operation.

The delay valve 20 has first and second orifices 22 inside.
．． The first orifice 22 is divided into two parts by a partition wall 24 having a diameter of 23, and the negative pressure passage 21 always passes through the first orifice 22 filled with a porous material.

Further, a valve body 25 made of an elastic body is fixed to the partition wall 24,
Under normal conditions, the valve portion is positioned so as to be in close contact with the surface of the partition wall, and when the negative pressure on the intake manifold side increases before and after the partition wall 24, it closes the second orifice 23, and the negative pressure on the negative pressure chamber 15 side increases the intake air. It has a check valve function that deforms and opens the second orifice 23 if it is larger than that on the manifold 7 side.

The operation of the embodiment having the above configuration will be described below.

Suhoor 18 at vacuum throttle valve 10
The force acting to the left in the figure is the elastic force of the spring 14, and the force acting to the right in the figure is the thrust due to the throttle pressure Pt acting on the left side of the spool 18, and the engine suction negative force acting on the diaphragm 13. It is a suction force due to pressure,
The spool 18 is positioned by these balances.

When the engine is running at low speed and under low load, the suction negative pressure is on the vacuum side, and the force of this negative pressure overcomes the elastic force of the spring 14, positioning the diaphragm 13 to the right, and reducing the force of the rod 17 pushing the spool 18. weaken.

At this time, the first land 18a of the spool 18 has a line pressure P
While the oil passage 32 for 1 is substantially closed, the oil passage 31 for throttle pressure pt is slightly communicated with the drain passage d by the intermediate portion of the second and second lands 18a, 18b, and the throttle pressure pt is drained.

Therefore, the throttle pressure Pt shows the smallest value.

As the engine accelerates toward high speed and high load, the suction negative pressure decreases and the spool 18 is gradually pushed and moved to the left in the figure.

Then, the drain passage d is gradually closed by the second land 18b, and the passage area of the oil passage 32 for the line pressure F'l is gradually opened by the first land 18a, so that the drain passage d for the throttle pressure pt is gradually closed. The pressure loss to gradually decreases,
The pressure loss of the line pressure Pl flowing from the oil passage 32 to the oil passage 33 also decreases accordingly.

Therefore, the relationship between engine suction negative pressure and throttle pressure Pt is
The result will be as shown in the figure.

The throttle pressure pt controlled in this way is the governor pressure Pg
Together with this, it acts on the shift valve 34 to perform an automatic gear shifting operation.

Now, as shown in Figure 1, when accelerating by depressing the accelerator pedal, the suction negative pressure decreases, so the negative pressure remaining in the negative pressure chamber 15 side becomes larger. The valve body 25 of the delay valve 20 is separated from the surface of the partition wall 24 and passes through the second orifice 23.

Therefore, the suction negative pressure is reduced to the negative pressure chamber 15 of the diaphragm device 11.
Then, the throttle pressure is controlled as described above and the gear is shifted to the D2 range.

When the accelerator pedal is released from the accelerator pedal after the acceleration is completed (point A in FIG. 1) and the vehicle enters steady running, the opening degree of the throttle valve 5 becomes smaller and the suction negative pressure rapidly increases.

In such a case, the valve body 25 is attracted by the increased suction negative pressure on the intake manifold 7 side and closes the second orifice 23.
2 is transmitted to the negative pressure chamber 15 of the diaphragm device 11, and its propagation θ time is delayed.

Therefore, the throttle ball Pt is held for a predetermined period of time due to the response delay of the vacuum throttle valve 10, or is gradually lowered, so that an immediate upshift does not occur.

If you want to accelerate immediately next time, you can apply it in D2 range, so you can press down on the accelerator pedal less.
In particular, increase in NOx emissions can be suppressed.

In addition, since the engine speed can be kept high, exhaust gas emissions can also be kept high, which helps reduce CO and HC emissions.

As explained above, the present invention returns the amount of depression of the accelerator pedal after the end of acceleration, and when accelerating again the next time, it can be done in a low gear position without having to shift up, resulting in good acceleration performance and no need for extra fuel. Because it does not require exhaust purification, especially N
It is effective in reducing Ox emissions and can prevent deterioration of fuel efficiency.

In addition, in an engine equipped with an exhaust gas recirculation device that recirculates part of the exhaust gas into the intake air, the negative pressure for operating the exhaust gas recirculation flow rate control valve, that is, the suction negative pressure or the negative pressure near the throttle valve, is affected by the amount of accelerator depression as described above. Since only a small amount is required, a large value can be maintained, sufficient exhaust gas recirculation can be performed, and the NOx reduction effect can be promoted.

Furthermore, since there are no changes when shifting up or down, you will not experience shift shock, and even if you are forced to shift up due to acceleration over time, the throttle pressure response when the accelerator is released is gentle, so the line pressure will not change. Changes are also gradual, reducing shift shock.

Incidentally, since the upshift caused by pressing the accelerator is not abrupt, automatic gear shifting is possible without any change from conventional gear shifting.

[Brief explanation of drawings]

Fig. 1 is a graph for explaining the shift characteristics of the conventional device and the embodiment of the present invention, Fig. 2 is a schematic configuration diagram showing one embodiment of the present invention, and Fig. 3 is the suction of the vacuum throttle valve of the same. It is a graph showing the change characteristics of negative pressure and throttle pressure. 7... Intake manifold, 10... Vacuum throttle valve, 11... Vacuum control diaphragm device,
15... Negative pressure chamber, 20... Delay valve, 21... Negative pressure passage, Pt...
Throttle pressure, Pl...line pressure.

Claims (1)

[Claims] 1. In a vehicle with an automatic transmission equipped with a vacuum throttle valve that obtains a throttle pressure corresponding to the engine suction negative pressure, the suction negative pressure is connected to a negative pressure passage that leads the engine suction negative pressure to the negative pressure chamber of the diaphragm device of the valve. An exhaust gas purification device characterized by being provided with a delay valve that guides the flow at a slower speed when increasing rapidly than when decreasing.