JPH01348A - Air cleaner clogging detection device for internal combustion engines - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of Industrial Application The present invention relates to a clogging detection device for detecting 11 clogging of an air cleaner for an internal combustion engine based on a low t of intake pipe pressure.
The present invention relates to a clogging detection device that is not affected by the pulsation of the pressure inside the intake pipe and is capable of reliable detection.

[Prior Art 1] In an internal combustion engine such as a vehicle engine, an air cleaner is usually provided in the middle of the engine intake pipe to remove dust from the air being taken in and prevent wear of the piston and cylinder.

Conventionally, such an air cleaner 11 clogging detection device for an internal combustion engine has generally utilized the fact that the intake pipe negative pressure increases as the L1 clogging of the air cleaner element progresses.

For example, in the device disclosed in Japanese Utility Model Application Publication No. 60-72969,
Clogging is indicated by the amount of deformation of the pressure receiving diaphragm that receives negative pressure in the intake pipe. Further, Japanese Utility Model Publication No. 59-36688 discloses a device that issues a clogging alarm when the amount of deformation of a pressure-receiving bellows exceeds a predetermined value.

Problem 1 to be Solved by the Invention By the way, since the flow in the engine intake pipe pulsates as the engine rotates, there is a problem that the "clogged" display fluctuates or a false alarm of clogging is issued. Ta.

Therefore, countermeasures can be taken, such as reducing the diameter of the pressure introduction tube that introduces the negative pressure in the intake pipe, or averaging the output signals of the pressure detector using software calculations, but in the former case, the pressure introduction tube with a sufficiently small diameter can be considered. Does it take -P time to make? In the case of a runner, the problem arises that the software becomes N-complex.

In view of the above problems, the present invention provides a clogging detection device for an air cleaner for an internal combustion engine, which has a simple structure and can accurately detect clogging of the air cleaner without being affected by intake pulsation pressure. The purpose is to

Means for Solving Problem 1 of the Invention (11" The pressure introduction pipes 2a, 2b are extended, and a pressure detector connected to the pressure introduction pipes 2a, 2b detects an increase in the negative pressure in the intake pipe 4, and a clogging signal 11 is issued.The pressure introduction pipe 2a is connected to the pressure introduction pipe 2a, 2b. , 2b, there is a valve body 6a which is biased towards the pressure detector 14 by spring members 5a, 5b (FIG. 1) and closes the pressure λ inlet pipes 2a, 2b.
6b is provided.

1 Action] When negative pressure is generated in the intake pipe 4, the valve bodies 6a, 6t') are moved against the spring force of the spring members 5a, 5b, opening the pressure introduction pipes 2a, 2b, and opening the pressure detector. 14, check the intake pipe negative pressure. When negative pressure is introduced, the valve bodies 6a, 6
b is almost in a closed state, but since the intake pipe negative pressure is pulsating, the valve bodies 6a, 6b follow this pulsation and generate slight vibrations near the closed position.

Therefore, the valve body 6a opens and closes at regular intervals due to slight vibrations.
, 6b, the pulsation is rectified and smoothed while passing through the minute opening gap between the valve bodies 6a, 6b, and these effects combine to reduce the pressure of the intake pipe entering the pressure sensor 14. Negative pressure is pulsating or well absorbed and resolved.

As the air cleaner 3 becomes clogged, the intake pipe negative pressure introduced into the pressure detector 14 increases, and a "1 clogged signal" is generated.

] - Effect of the invention 1 According to the present invention, the pulsation of the intake pipe negative pressure introduced into the pressure detector can be effectively eliminated by a simple structure in which a valve body is provided in the pressure introduction pipe, and the detection device There will be no fluctuations in the clogging display or erroneous activation of the clogging alarm.

In the present invention, it is not necessary to create a pressure introducing tube with a minute diameter, and the software does not become complicated.

[Embodiment] In FIG. 2, an air cleaner 3 is provided on the intake pipe 4 leading to the internal combustion engine 7, and from the intake pipe 4, pressure introduction pipes 2; , 2b extend to reach the pressure detection section 1. A clogging warning light 8 is connected to the pressure detection section 1, and the warning light 8 is connected to a power source 9.

Details of the pressure detection section 1 are shown in FIG. 11. The main body housing 11 of the detection unit 1 is a double cylindrical body consisting of an inner and outer cylinder,
The above-mentioned pressure introduction pipes 2 are provided on both end faces of the housing 11, respectively.
a, 2 [joint pipes connecting the pipes] 2a, 12b are formed in a protruding manner. A cylindrical holding member 13 made of rubber or resin is provided at the center of the inner cylinder that communicates with each of the joint pipes 12a and 12b, with the center of the peripheral wall sandwiched between the inner cylinder walls.
A semiconductor pressure-sensitive chip 14, which will be described in detail later, is held across the center of the cylinder.

Inside the left and right inner cylinders of the holding member 13 are coil springs 5a,
Valve bodies 6a and 6b biased by 5b are disposed,
These valve bodies 6a, 6b abut against the end surface of the holding member 13 to close the gap [1]. The valve body is made of rubber or resin.

The output of the semiconductor pressure-sensitive chip 14 is input to a circuit board 5 provided between the inner cylinder and the outer cylinder, and the details of the circuit board 15 will be described later.

The details of the semiconductor pressure-sensitive chip 14 will be explained with reference to FIGS. 3 and 4. On the silicon chip 141, which also serves as a diaphragm, there are a diffusion lead part 142, semiconductor strain gauges 143a, 1
-43 b, 143C1143d, and metal electrode 14
4 is formed of a vapor deposited film or the like, and a protective film]-45 made of an insulating film such as S i 02 is formed on its upper surface.

The semiconductor strain gauges 143a, 143b, 1-43c
, 143d connects the bridge circuit to the rod 1 as shown in FIG.
It is connected to the circuit board 15 by a lead wire 16. On the circuit board 15, there are provided a seven amplifier circuit C imitating an operational amplifier and a transistor "" which is activated by the output of the comparator and lights up the clogging warning light 8. 1) are connected to the power source 1 and the clogged warning light 8, respectively.

In the above configuration, when the internal combustion engine is operating, negative pressure on the downstream and upstream sides of the intake pipe 4 is introduced into the inner cylinder of the pressure detection housing 11 via the pressure introduction pipes 2a and 2b, and each valve body 6
a and 6b are opened, and negative pressure is applied to both sides of the semiconductor pressure-sensitive chip 14. The pressure-sensitive chip 14 deforms according to the difference in negative pressure applied, and this shape distortion causes the strain gauge 143a to deform.
, 143b, 143c, 1.43 ci. In addition, each of the above-mentioned valve bodies 6a, 6b is connected to the above-mentioned pressure sensitive chip 14.
After introducing negative pressure, it becomes almost closed.

By the way, the intake pipe negative pressure pulsates depending on the rotation speed of the internal combustion engine, and the pulsation period is, for example, 3000 rpm.
1.6 m s''C' in a four-cylinder engine (Fig. 6 (1)).Here, in the I■+ clogging detection device of the present invention, the valve bodies 6a, 6L) are connected to the intake pipe negative 1, which generates minute vibrations near the closed position following pressure pulsations, and opens and closes at the pulsation cycle; and, the valve body 6 opens and closes at regular intervals due to the minute vibrations;
The pulsation is rectified by i, 6b, and the valve body 6a,
6b while passing through the minute opening gap (6th
Figure (2)).

The negative pressure in the intake pipe on the upstream side and f''tAE side, where the pulsation has been absorbed and eliminated, simply increases as the air cleaner 3 becomes clogged 1-1, and when the differential pressure exceeds a certain value, the strain gauge output The comparator C that receives the signal is activated, clogging 5.p occurs, and the J4 light 8 lights up.

Note that when the internal combustion engine is stopped, the valve bodies 6b are closed and the lowest negative pressure is maintained on both sides of the semiconductor pressure-sensitive chip 14 before the engine stops, but normally the pressure remains constant due to leakage from the valve bodies 6a and 6b. After a period of time (for example, about 2 minutes), the pressure returns to the atmosphere and is reset.

In this case, it is of course possible to provide a reset means for forcibly opening the valve bodies 6a, 6b.

In the above embodiment, the negative pressure in the intake pipe on the upstream and downstream sides of the air cleaner was applied to the semiconductor pressure-sensitive chip, and the differential pressure was detected. Since it is a negative pressure in the upstream intake pipe, the upstream negative pressure is approximated by atmospheric pressure, and as shown in FIG. 7, the differential pressure between the upstream intake pipe negative pressure and atmospheric pressure is detected. It may also be J-sei.

In the figure, a main body housing 1 of a detecting unit 1 is a double cylindrical body consisting of an inner and outer cylinder, and a joint pipe 12a for connecting a pressure introduction pipe 2a is formed protruding from the end face of the housing 1.

The pressure introduction pipe 2a is connected to the air cleaner downstream side of the intake pipe 4 (FIG. 8).

A cylindrical holding member 13 with an open negative end is provided at the end of the inner cylinder that communicates with the above-mentioned joint pipe 2a, and the holding member 2a holds a semiconductor (δ pressure chip 14). A valve body 6a urged by a coil spring 5a contacts the opening of the holding member 13 to close it.

The atmosphere is sealed in the space 146 formed by the pressure-sensitive chip 14 and the closed end of the holding member.
Even with the six configurations, pulsations in the negative pressure of the intake pipe can be effectively eliminated and clogging can be reliably detected.

[Brief explanation of the drawing]

1 to 6 show an embodiment of the 11 clogging detection device of the present invention, FIG. 1 is an overall sectional view of the clogging detection device, and FIG. 2 is a concept of an air cleaner for an internal combustion engine to which the present invention is applied. figure,
Figures 3 to 4 are half-paragraphs: a front view and a cross-sectional view of the sensing pressure chip, Figure 5 is a circuit diagram of the pressure detection section, and Figure 6 is a diagram showing the state of pulsating pressure. Figure 7-
FIG. 8 shows another embodiment, FIG. 7 is a general sectional view of the clogging detection device, and FIG. 8 is a conceptual diagram of an air cleaner for an internal combustion engine to which the present invention is applied. ]4...Semiconductor pressure sensitive chip (pressure detector) 2a, 2b
...Pressure intake pipe 3...Air clear 4...Inner cut (engine intake pipe 11.5b...Coil spring (spring member) (')a,
0[)...1 valve fA1 Figure 3 Figure 6 Figure 7 page Figure 8

Claims (1)

[Claims] An air cleaner for an internal combustion engine in which a pressure introduction pipe extends from an intake pipe for an internal combustion engine equipped with an air cleaner, and a pressure detector connected to the pressure introduction pipe detects an increase in negative pressure in the intake pipe and issues a clogging signal. A clogging detection device for an air cleaner for an internal combustion engine, characterized in that the pressure introduction pipe is provided with a valve body that is biased toward the pressure detector by a spring member midway through the pressure introduction pipe to close the pressure introduction pipe. .