JPH02267362A - Fuel filter - Google Patents

Abstract

PURPOSE:To enable detection of alcoholic concentration which is not under the influence of air bubbles in fuel by providing an alcoholic concentration detecting device on a fuel filter, and also providing a pair of electrodes on the bottom part inside a cylindrical body through which communicating holes passing through an axial hollow space part (a fuel chamber) in radial direction are formed. CONSTITUTION:A fuel element 1 is constituted by mounting a filter element 3 inside a cylindrical case main body 2 having a bottom, and a fuel supply device and a fuel tank are respectively connected to an outlet port 2a and an inlet port 4a. There is a shaft part in the nearly center part of a case cover body 4, and an alcoholic concentration detecting device 10 is arranged on the top end thereof. In this concentration detecting device 10, there is a cylindrical cylinder body 11 made of an insulation material and having a bottom, is, and a plurality of communication holes 11a are drilled so as to communicate to a center fuel chamber 12, in the radial direction. And a first electrode 13 is stuck on the wall surface along the inner periphery of the cylindrical body part 11b of the cylinder body 11 for sectioning the fuel chamber 12, and a second electrode 14 is fit on a bottom part 11c, so that alcoholic concentration is detected by the variation in the static capacity between both electrodes 13, 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fuel filter equipped with an alcohol concentration detection device for alcohol mixed fuel used as automobile fuel.

[Prior Art] Recently, alcohol mixed fuel, which is a mixture of alcohol such as ethanol and methanol with gasoline or the like, has been used as a fuel for automobiles. This alcohol mixed fuel differs from gasoline etc. in terms of distillation properties, etc., so when supplying alcohol mixed fuel to the internal combustion engine of a car that uses gasoline etc. as fuel, it is necessary to take measures according to the mixing ratio of alcohol, that is, the alcohol concentration. becomes.

For example, when using low-concentration fuel with alcohol content of 10% or less, it is possible to adapt it by partially modifying an existing internal combustion engine that uses gasoline as fuel, but to ensure stable operation of the internal combustion engine, alcohol It is necessary to adjust the fuel supply amount, ignition timing, etc. according to the concentration. Moreover, since the alcohol concentration of currently available alcohol-mixed fuels varies depending on various circumstances, uniform adjustment for internal combustion engines is insufficient. Therefore, in order to accurately perform the above adjustment, a means for detecting the alcohol concentration is first required. Further, when the alcohol concentration in the fuel is high, it is necessary to develop an engine that is compatible with the fuel properties, and in this case also, a means for detecting the alcohol concentration is required.

For example, in Japanese Unexamined Patent Application Publication No. 56-98540, a capacitance means is provided in the middle of the alcohol mixed fuel flow path, and the change in capacitance as the alcohol mixed fuel passes is measured. An alcohol sensor for detecting a proportion is disclosed. In contrast to this alcohol sensor, Japanese Patent Laid-Open No. 104240/1983 discloses an alcohol sensor that is arranged diagonally so that the line connecting the inlet and outlet is tilted upward by about 15 degrees with respect to the horizontal to prevent air bubbles from accumulating. Proposed.

Furthermore, Japanese Patent Laid-Open No. 57-101753 discloses a method and apparatus for detecting alcohol concentration by filling alcohol mixed fuel between electrode plates disposed opposite each other and measuring the impedance between the electrode plates. has been done. The device described in the publication is characterized in that a fuel chamber is provided through which alcohol-mixed fuel enters and exits, and two electrode plates are disposed within this fuel chamber. Similarly, an alcohol mixture ratio sensor equipped with a two-pole electrode plate is disclosed in Japanese Utility Model Application No. 61-92866, and measures the alcohol mixture ratio based on the electrical conductivity of a liquid mixture of alcohol and gasoline. It is stated that

Furthermore, Japanese Patent Application Laid-Open No. 59-190641 proposes an alcohol content sensor equipped with a microwave transmitting/receiving means in which a fuel pipe is passed through the cavity of a microwave cavity resonator, and the alcohol content rate in the fuel is measured. It is planned to detect this from outside the fuel pipe.

[Problems to be Solved by the Invention] Although the above-mentioned conventional publications disclose the detection principle or the concept of the detection means in the alcohol concentration detection device,
It is unclear what countermeasures will be taken in relation to the fuel properties when the device is installed in an internal combustion engine. For example, JP-A-57-1
The device described in Publication No. 01753 is provided with a fuel chamber, but if bubbles are generated in the fuel in the fuel chamber, there is a risk that the bubbles may accumulate near the electrode plate and cause measurement errors, so some countermeasures must be taken. It becomes necessary.

The above-mentioned Japanese Patent Laid-Open No. 56-104240 discloses a technique in which a flow path is sloped to prevent air bubbles from accumulating, or a leaf spring is provided to allow air bubbles to separate from an electrode, thereby giving an image to a sensor. . In this publication, it is assumed that the capacitance means is installed in a horizontally arranged flow path, and the capacitance means is installed at an angle in the middle of the flow path between the filter element and the fuel supply device. Examples are disclosed. However, this filter element is provided separately from the previous fuel filter in the fuel supply system and is not related to each other. Furthermore, when the engine is restarted after operation, the entire capacitance means may be filled with fuel containing bubbles, making measurement impossible.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fuel filter equipped with an alcohol concentration detection device that can reliably detect alcohol concentration without being affected by air bubbles in the fuel.

[Means for Solving the Problem] In order to achieve the above object, the present invention accommodates a filter element in a case, and provides an inlet port and an outlet port on both sides through the filter element, and provides fuel supply for an internal combustion engine. In the fuel filter disposed in the system, the cylindrical body is interposed in the fuel passage passing through the filter element in the case, and a communication hole passing through the axially hollow part is bored in the radial direction. Along with communicating with
a cylindrical body whose axial end surface is joined to the case and defines a fuel chamber in the axial hollow part; a first electrode attached to a position exposed to the fuel chamber on an inner wall surface of the cylindrical body; an alcohol concentration detection device including a second electrode placed substantially on the axis of the cylindrical body so as to face the first electrode; It is arranged so that it is located at the bottom.

[Function] The fuel filter configured as described above is equipped with an alcohol concentration detection device, and detects internal combustion so that the fuel chamber in the cylinder is located below the communication hole in the cylinder that communicates with the fuel passage passing through the filter element. Installed in the engine's fuel supply system.

The alcohol-mixed fuel flows in from the artificial port of the fuel filter, and the filter element removes dust, moisture, etc. from the fuel, and the fuel is supplied to the internal combustion engine from the outlet port. During this time, inside the fuel filter,
The alcohol mixture fuel flows into the cylinder through the communication hole of the alcohol concentration detection device through the filter element, and flows out from the communication hole. At this point, if the alcohol mixed fuel contains air bubbles, even if the air bubbles flow into the cylinder together with the fuel, they will flow out from the communication hole as is, and only the fuel will pass through the communication hole into the fuel chamber below the communication hole. Inflow and outflow. That is,
Gas-liquid separation is performed through communication holes formed in the cylindrical body.
Air bubbles are prevented from entering the fuel chamber. Therefore, only the alcohol mixed fuel passes between the first electrode and the second electrode in the fuel chamber. Thereby, for example, the capacitance between the two electrodes is detected, and the alcohol concentration is detected according to the change in this capacitance.

[Embodiments] Hereinafter, preferred embodiments of the fuel filter of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the fuel filter of the present invention, which is installed in a fuel supply system of an internal combustion engine, and an alcohol concentration detection device 10 is housed in the fuel filter 1. As shown in FIG. The fuel filter 1 is interposed between a fuel tank (not shown) and a fuel supply device, and is configured to remove dust and moisture from the fuel supplied to the carburetor, fuel injection device, etc. that constitute the latter. There is. That is, a well-known filter element 3 is installed in a bottomed cylindrical metal case body 2, and both sides thereof are connected to the fuel tank and the fuel supply device, respectively.

An outlet port 2a is provided at the bottom of the case body 2, and is communicatively connected to a fuel supply device (not shown). A disc-shaped case lid 4 made of synthetic resin is fitted into the open end of the case body 2. The case lid 4 has a cylindrical shaft approximately in the center, and the alcohol concentration detection device 10 is fixed to the tip of the shaft.

The alcohol concentration detection device 10, as shown in FIG.
The open end of a bottomed cylindrical body 11 made of an insulating material such as synthetic resin or ceramic is in close contact with the bottom surface of the case body 2 . A plurality of communication holes 11a are bored in the radial direction near the bottom 11c of the cylinder 11, and these communication holes 1
1a passes through the axial hollow portion of the cylinder 11. A fuel chamber 12 is formed by the hollow portion of this cylindrical body 11 .

A first electrode 13 is attached to the inner wall surface of the cylindrical body portion 11b of the cylindrical body 11 within the fuel chamber 12. The first electrode 13 is provided with a conductor on the inner periphery of the cylindrical body portion 11b by adhesion, vapor deposition, etc.
Lead wire 2 buried in the cylindrical body part 11b and the bottom part lie
1 and is electrically connected. Further, a second electrode is provided on the bottom portion 11c approximately at the axis of the cylinder body 11 so as to face the first electrode 13.
The electrode 14 is fitted through a seal ring 14a. The second electrode 14 is a cylindrical conductor, but instead of this, a conductor may be provided on a resin cylinder by adhesion, vapor deposition, etc.
It can also be formed by extending from. The second wire 8i14 is electrically connected to the lead wire 22. The case lid 4 is resin molded including these lead wires 21 and 22, and the connector 15 and the artificial port 4a are integrally formed. That is, the case lid 4 is fixedly formed integrally with the cylindrical body 11.

The connector 15 is connected to a detection circuit (not shown), and lead wires 21 and 22 are electrically connected thereto. The first electrode 13 and the second electrode 14 constitute a capacitance means.

The fuel filter 1 equipped with the alcohol concentration detection device 10 is arranged in a fuel supply system of an internal combustion engine (not shown) so that the fuel chamber 12 of the alcohol concentration detection device 10 is located below the communication hole 11a. Ru. The alcohol mixed fuel is piped so that it flows in from the upper inlet port 4a and flows out from the lower outlet port 1-2a.

Thereby, the alcohol mixed fuel that has flowed into the fuel filter 1 is filtered when passing through the filter element 3, and dirt and moisture are removed.

At this time, in the alcohol concentration detection device 10, if bubbles are included in the alcohol mixed fuel flowing into the cylinder 11 from the communication hole 11a, the bubbles flow out from the communication hole 11a together with the fuel, and only the fuel flows into and out of the fuel chamber 12. That is, gas-liquid separation of the alcohol mixed fuel is performed, and entry of air bubbles into the fuel chamber 12 is prevented.

Therefore, in the fuel chamber 12, only the alcohol mixed fuel passes between the first electrode 13 and the second electrode 14 that face each other.

A connector 15 connected to a detection circuit (not shown)
The capacitance between the first electrode 13 and the second electrode 14 is detected via the lead wires 21 and 22. Note that this method of detecting alcohol concentration based on capacitance is well known, so a description thereof will be omitted. In this case, as described above, since the alcohol mixed fuel between the first electrode 13 and the second electrode 14 does not contain air bubbles, it is possible to accurately detect the alcohol concentration without causing an error. . Furthermore, since the fuel filter 1 is installed near the cylinders of the internal combustion engine, and the alcohol-mixed fuel is in a state immediately before being supplied to the internal combustion engine, it is possible to detect the alcohol concentration suitable for controlling fuel supply, ignition timing, etc. can.

In the above embodiment, the alcohol concentration detection device 1o is arranged vertically within the fuel filter 1, but it does not necessarily have to be vertical, and may be arranged at an angle to prevent air bubbles from flowing into the fuel chamber 12. good.

[Effects of the Invention] Since the present invention is configured as described above, it produces the effects described below.

That is, in the fuel filter of the present invention, the alcohol concentration detection device is housed, and the number of parts and the number of assembly steps are reduced compared to the conventional structure in which both are provided separately. In particular, air bubbles in the alcohol mixed fuel supplied to the alcohol concentration detection device are separated and only the fuel passes between the first electrode and the second electrode. The alcohol concentration of alcohol can be detected accurately. Furthermore, since the fuel filter is installed near the cylinders of the internal combustion engine, the alcohol concentration detection device detects the alcohol concentration of the alcohol mixed fuel immediately before being supplied to the internal combustion engine. Therefore,
Accurate alcohol concentration signals can be supplied for controlling fuel supply, ignition timing, etc.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a fuel filter according to an embodiment of the present invention, and FIG. 2 is a partially sectional perspective view of an alcohol concentration detection device housed in the fuel filter according to an embodiment of the present invention. 1...Fuel filter, 2...Case body. 2a... Outlet port, 3... Filter element. 4...Case lid, 4a...Inlet port. 10...Alcohol concentration detection device. 11... Cylindrical body, 11a... Communication hole, 12...
fuel room. 13...First electrode, 14...Second electrode.

Claims (1)

[Claims] (1) A fuel filter that houses a filter element in a case and has an inlet port and an outlet port on both sides through the filter element, and is arranged in a fuel supply system of an internal combustion engine, in which the filter element is housed in the case. A cylindrical body interposed in a fuel passage passing through, a communication hole passing through an axial hollow part is bored in the radial direction to communicate with the fuel passage, and an axial end face is joined to the case, and the axial direction A cylindrical body defining a fuel chamber in a hollow part, and a first cylindrical body attached to an inner wall surface of the cylindrical body at a position exposed to the fuel chamber.
and a second electrode disposed approximately on the axis of the cylindrical body so as to face the first electrode, the alcohol concentration detection device being connected to the fuel chamber. A fuel filter, characterized in that the fuel filter is disposed below the communication hole.