JPS6038037Y2 - Engine acceleration detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an acceleration detection device for engines, particularly automobile engines.

Conventionally, the first chamber and the second chamber are connected through a diaphragm in the main body.
The first chamber is communicated with the intake passage downstream of the throttle valve (carburizer throttle valve or mixer throttle valve), and the second chamber is communicated with the atmosphere or the intake passage downstream of the throttle valve through the throttle. It also communicates with the intake passage downstream of the throttle valve via a check valve that opens when the suction negative pressure downstream of the throttle valve is greater than the second chamber, and the first chamber and the An acceleration detection device is known that detects an acceleration state by changing a diaphragm due to a negative pressure difference between two chambers, thereby moving a shaft fixed to the diaphragm.

The operating characteristics of this type of acceleration detection device are as follows: the effective pressure receiving area S1 of the diaphragm of the first chamber and the second chamber. Controlled by S2.

That is, the suction negative pressure in the intake passage downstream of the throttle valve immediately before acceleration is P.

, if the suction negative pressure during acceleration is P, then the pressures in the first and second chambers during acceleration are P1 in the first chamber and P in the second chamber.

You can think of it as.

(Both pot p is the absolute value of negative pressure).

Due to the pressure difference generated between the two chambers during acceleration, a force (32PO5IP) is generated that displaces the diaphragm, in other words, the shaft fixed to the diaphragm, toward the second chamber, and this force exceeds the set value F. The acceleration detection device is activated when

Therefore, the operating range of the acceleration detection device is as follows.

52Po-31P≧F Here, the change in suction negative pressure before acceleration and during acceleration In other words, the differential pressure between the first chamber and the second chamber is ΔP and the negative pressure P before acceleration.

Rewriting the above equation, the operating range can be expressed as follows.

ΔP≧(IS2/51)PO+F7S1 (
1) (ΔP<Po) That is, basically, the effective pressure receiving area S1 of the diaphragm of the first chamber and the second chamber. S2 and set value F determine the operating characteristics of the acceleration detection device.

The set value F is a constant determined by a spring, etc. that regulates the diaphragm of the acceleration detection device, and a switch, etc., which is the object of operation of the acceleration detection device.

The present invention provides an acceleration detection device for an engine in which the shaft is disposed on the first chamber side, where P in the above equation (1).

The coefficient (1-32/31) of the shaft is smaller than 0, that is, Sl<32. Bellows are provided to maintain airtightness in the first chamber by being attached to the main body on the first chamber side, and the inner circumferential surface of the bellows and the end surface of the shaft on the other end side of the bellows are opened to the atmosphere. By setting the bellows more closely, the sliding area of each sliding part accompanying the operation of the acceleration detection device is not increased, and the inner peripheral surface of the bellows and the shaft are Since the pressure acting on the end face of the bellows on the other end side does not decrease when the throttle valve opens, substantially the first
The effective pressure-receiving area S1 of the diaphragm of the chamber does not change, and it is possible to effectively set <Sl<32 as described above, thereby achieving both airtightness and smooth operation in the first chamber, and a low load (po High load (po is small) when accelerating from
Therefore, it is possible to obtain an acceleration detection device that can perform a detection operation with a smaller acceleration (smaller negative pressure change ΔP) than the acceleration from .

FIG. 2 shows an example of the operating region (indicated by diagonal lines) of the acceleration detection device according to the present invention.

Hereinafter, a case where the acceleration detection device of the present invention is used to control the operation of an exhaust gas recirculation device will be explained with reference to the drawings.

In Fig. 1, 1 is an intake passage, 2 is a throttle valve, and 3 is an exhaust gas recirculation device, which includes an engine exhaust system and an intake system (not shown).
an exhaust gas recirculation passage 4 communicating with the exhaust gas recirculation passage 4;
It consists of a valve body 5 that opens and closes, and a diaphragm device 6 that controls the valve body 5.

The negative pressure chamber 6a of the diaphragm device 6 is communicated with a position immediately upstream of the throttle valve 2 of the intake passage 1 when the throttle valve 2 is fully closed by a negative pressure passage 7 having an on-off valve 8 in the middle, and when the throttle valve 2 is set to open. When the temperature exceeds 50°C and the on-off valve 8 is open, the valve body 5 is opened in response to the suction negative pressure to recirculate the exhaust gas.

The on-off valve 8 provided in the negative pressure passage 7 is a normally closed solenoid valve that opens the passage only when the key switch 9 and the microswitch 10 are closed. It will be closed.

The acceleration detection device 11 includes a diaphragm 12 inside the main body 11a.
The first chamber 13 and the second chamber 1 are separated and placed opposite each other.
4, the first chamber 13 communicates with the intake passage 1 downstream of the throttle valve 2 through a negative pressure passage 15, and the second chamber 14 communicates with the intake passage 1 downstream of the throttle valve 2 from the throttle 16 and the second chamber 14. It is communicated with the negative pressure passage 15 through a passage 18 in which a check valve 17 that opens when the pressure is high is arranged in parallel.

Reference numeral 19 denotes a shaft fixed to the diaphragm 12 and disposed on the first chamber 13 side. One end 2 of the bellows 21 arranged
1a is fixed to the surface of the diaphragm 12 on the first chamber 13 side.

The other end 21b of the bead 21, whose one end 21a is in close contact with the diaphragm 12, is in close contact with the main body 11a on the side of the first chamber 13 to keep the first chamber 13 airtight.

Further, a spring 23 equipped with an adjustment screw 22 is housed in the second chamber 14 .

The washer 20 effectively brings the one end 21a of the bellows 21 into close contact with the diaphragm 12 and reduces the effective pressure receiving area of the diaphragm 12 on the first chamber 13 side.
It is also possible to have a structure in which one end portion of the holder and the holder are brought into close contact with each other with an adhesive.

That is, the diaphragm 1 of the first chamber 13 and the second chamber 14
The effective pressure receiving area of No. 2 is reduced on the first chamber 13 side by the area where one end 21a of the bellows 21 is in close contact with the diaphragm 12.

A throttle 16 and a check valve 17 are arranged in parallel in the middle of the negative pressure passage 18 of the second chamber 14. When the negative pressure in the intake passage 1 increases, the check valve 17 opens and immediately transmits the negative pressure to the second chamber 14. However, since the check valve 17 closes when the negative pressure decreases, the negative pressure is gradually transmitted only by the throttle 16.

The microswitch 10 is connected to the shaft 1 of the acceleration detection device 11.
The bellows 21 is arranged so as to be closed when the bellows 9 is displaced toward the second chamber 14, and the inner peripheral surface of the bellows 21 and the shaft 19
contact surface with the microswitch 10 (bellows other end 2
1b side) is always in contact with the atmosphere.

Next, the operation of the above embodiment will be explained.

During acceleration, when the throttle valve 2 of the intake passage 1 opens and the negative suction pressure of the intake passage 1 decreases, the negative pressure of the first chamber 13 decreases immediately via the negative pressure passage 15, but the negative pressure of the second chamber 14 decreases. Since the check valve 17 in the passage 18 is closed, negative pressure changes are gradually transmitted from the throttle 16, and the negative pressure before acceleration is maintained for a certain period of time.

This pressure difference between the two chambers lifts the diaphragm 12 and the shaft 19 fixed thereto against the spring 23, thereby closing the switch 10.

When the microswitch 10 closes, the on-off valve 8 opens the negative pressure passage 7 of the exhaust gas recirculation device 3, suction negative pressure is introduced into the negative pressure chamber 6a of the diaphragm device 6, and the valve body 5 opens the exhaust gas recirculation passage 4. Exhaust gas is recirculated from the engine's exhaust system to the intake system.

In the acceleration detection device 11, the effective pressure receiving area of the diaphragm 12 on the first chamber 13 side is reduced by the bellows 21 compared to the second chamber 14 side, and the inner peripheral surface of the bellows 21 and the microswitch 10 on the shaft 19 The diaphragm 1 on the first chamber 13 side is opened to the atmosphere.
Since the effective pressure-receiving area of 2 is not substantially increased, let's compare the acceleration from a low load where the suction negative pressure in the intake passage 1 is large and the acceleration from a high load where the suction negative pressure is small. When accelerating from a high load, the detection device 11 does not perform a detection operation unless there is a negative pressure change greater than the negative pressure change in the intake passage 1 that occurs when accelerating from a low load.

With this configuration, the acceleration detection device 11
Each sliding part accompanying the operation of, for example, the main body 11 on the first chamber 13 side
the first chamber 1 of the diaphragm 12 without increasing the sliding area between the seal member attached to the shaft 19 and the shaft 19.
As described above, the effective pressure-receiving area between the third side and the second chamber 14 side can be differentiated as described above, and the first chamber 13 can be airtight and operate smoothly, and the exhaust gas purification is normally required. When accelerating from low loads, which are used overwhelmingly in city driving, the system detects even small accelerations and recirculates exhaust gas to sufficiently reduce NOx, and when accelerating from high loads, it detects even small accelerations. drivability can be ensured by not detecting the exhaust gas and preventing exhaust gas recirculation as much as possible.

In the above embodiment, the second chamber is communicated with the intake passage downstream of the throttle valve through the throttle, but it is also possible to communicate the second chamber with the atmosphere (pure atmosphere, air cleaner, etc.) through the throttle. A similar effect can be obtained by using a configuration in which:

Further, in the above embodiment, the case where the acceleration detection device according to the present invention is applied to an exhaust gas recirculation device is described, but the application of the acceleration detection device according to the present invention is not limited to this.
Of course, it can also be used for fuel control and ignition timing control.

As described above, according to the present invention, it is possible to achieve both airtightness in the first chamber and smooth operation, and while it can operate even with a small negative pressure change when accelerating from a low load, it does not require a large negative pressure change when accelerating from a high load. Since it is possible to obtain an acceleration detection device that would otherwise not operate, it is possible to provide favorable operating characteristics to this exhaust gas purification device, especially when used to operate an exhaust gas purification device such as an exhaust gas recirculation device. becomes.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a diagram showing the operating characteristics of the acceleration detection device according to the present invention. 1... Intake passage, 2... Throttle valve, 3...
... Exhaust gas recirculation device, 11 ... Acceleration detection device, lla ... Main body, 12 ... Diaphragm, 13 ... First chamber, 14・・・・・・
2nd chamber, 16... throttle, 17... check valve, 210... bellows, 21a...◆
...One end of the bellows, 21b...The other end of the bellows.

Claims (1)

[Scope of utility model registration request] A first chamber and a second chamber are arranged opposite each other in the main body via a diaphragm, the first chamber is communicated with the intake passage downstream of the throttle valve, and the second chamber is connected to the atmosphere or the air downstream of the throttle valve through the throttle. The first chamber is connected to the intake passage downstream of the throttle valve through a check valve that opens when the intake negative pressure downstream of the throttle valve is greater than the second chamber. Acceleration of an engine in which an acceleration state is detected by displacing a diaphragm due to a negative pressure difference between a chamber and a second chamber, thereby moving a shaft fixed to the first diaphragm and disposed on the first chamber side. The detection device is arranged to surround the shaft, and has one end connected to the first
The other end is attached to the diaphragm surface on the chamber side and the main body on the first chamber side, thereby maintaining airtightness in the first chamber and increasing the effective pressure receiving area of the diaphragm on the first chamber side. Acceleration of an engine characterized in that a bellows is provided to reduce the effective pressure receiving area of the diaphragm on the second chamber side, and the inner peripheral surface of the bellows and the end surface of the shaft on the other end side of the bellows are opened to the atmosphere. Detection device.