KR20010081439A - Structure for mounting miniature high-sensitive optical-fiber pressure sensor to engine - Google Patents

Abstract

PURPOSE: Engine installing structure for an optical fiber pressure sensor is provided to minimize damage to a cylinder while conveniently replacing the sensor through installing the sensor in a head bolt combining a cylinder head and a cylinder block. CONSTITUTION: A pressure sensor(30) is inserted to a head bolt(20) having an insertion hole(23) for locating the sensor on a fluctuating space(44). Then, the head bolt combines a cylinder head(10) and a cylinder block(12). In a sealed state of the cylinder, a through hole(40) on the cylinder head and the fluctuating space of the head bolt are matched. To replace the pressure sensor, the head bolt is removed. After replacing the pressure sensor in the insertion hole, the head bolt is combined again. The pressure sensor receives pressure in the cylinder through the through hole on the cylinder head and the fluctuating space in the head bolt. Moreover, data about the pressure of the cylinder are transferred to an external measuring apparatus through an optical fiber(32) connected to the sensor.

Description

STRUCTURE FOR MOUNTING MINIATURE HIGH-SENSITIVE OPTICAL-FIBER PRESSURE SENSOR TO ENGINE}

An object of the present invention relates to a structure for mounting a sensor for detecting the combustion pressure in the cylinder of the engine, and more particularly, inserting the combustion pressure sensor into the head bolt connecting the cylinder head and the cylinder block does not hurt the cylinder. The present invention relates to an engine mounting structure of a sensor that is easy to manufacture and convenient to repair and replace.

In general, the engine provides power to the outside through the intake, compression, explosion, and exhaust stroke by the reciprocating motion of the piston in the cylinder, the performance of the engine greatly depends on the degree of compression and explosion by the piston. Therefore, it is essential to measure the combustion pressure in the cylinder to test the engine.

However, since it is very important that the cylinder is hermetically sealed due to the characteristics of the engine, it was very difficult to attach the sensor and to connect the sensor to measure the pressure inside the cylinder.

In order to use a pressure sensor in an engine, a spark plug is mainly used in a gasoline engine and a hole in a cylinder head or a cylinder block is often installed in a diesel engine. In the case of installing a hole in a diesel engine, it was necessary to avoid a cooling water passage to cool the engine, and to maintain the airtightness of the engine, there was no suitable place for installing a pressure sensor except for a spark plug or a cylinder head.

However, such a structure has to be designed to avoid various parts such as a coolant channel, a cam, a valve, and the like arranged around the cylinder block and the cylinder head.

The pressure sensor must be installed between the cylinder head and the highest point when the piston reciprocates up and down in the cylinder to measure compression and combustion explosion pressure. However, the current sensor is about 5 ~ 10mm in diameter, it is very difficult to secure enough space to install the sensor in the engine. In addition, if the drilled hole does not match the sensor for mounting the sensor, or if you want to use a sensor of a different standard in the hole already installed, you must use a separate adapter, and if the hole for installing the sensor is damaged or molded incorrectly in the manufacturing process, Sensors can not be installed, so expensive components can be wasted and unnecessary costs are wasted.

The present invention has been made to solve the above problems of the prior art, an object of the present invention is to damage the cylinder itself by mounting a sensor for detecting the combustion pressure in the head bolt coupling the cylinder head and cylinder block of the engine It is to provide an engine mounting structure of the sensor while reducing the installation and easy installation and replacement of the sensor.

It is another object of the present invention to provide an engine mounting structure of a sensor configured to transmit a pressure in a cylinder to a combustion pressure sensor inserted into the head bolt by installing a through hole in the cylinder head and forming a corresponding tab and flow space in the head bolt. It is.

Another object of the present invention is to install a ring on top of the combustion pressure sensor to prevent the pressure of the cylinder to flow out through the insertion hole formed in the head bolt to the engine mounting structure of the sensor that can maintain the air tightness of the engine To provide.

Still another object of the present invention is to provide an engine mounting structure of a sensor that can reduce the cost and reduce the structure by using a high sensitivity optical fiber pressure sensor as a combustion pressure sensor.

In order to achieve the above object, the present invention is a structure for mounting a combustion pressure sensor in an engine formed of a cylinder head, a cylinder block and a piston, comprising a head bolt for coupling the cylinder head to the cylinder block, It provides an engine mounting structure of the sensor, characterized in that the combustion head sensor is inserted into the head bolt for detecting the state of the engine.

Preferably, the cylinder head has a through hole connecting the inside of the cylinder and the combustion pressure sensor to a position corresponding to the combustion pressure sensor.

The head bolt has a tab formed at a position of a screw thread contacting the through hole, the tab preferably forms a flow space for the pressure in the cylinder flows from the through hole to the combustion pressure sensor.

The head bolt is preferably formed with an insertion hole for inserting the combustion pressure sensor to the upper side of the tab and blocked below the tab.

The combustion pressure sensor is located in the upper portion of the flow space formed by the tab, it is preferable to be connected to the outside by the optical fiber through the insertion hole of the head bolt.

The head bolt may have a ring at the edge of the combustion pressure sensor to prevent the pressure of the cylinder from leaking.

The combustion pressure sensor is preferably a high sensitivity optical fiber pressure sensor.

1 is a cross-sectional view showing a structure in which a sensor is mounted on an engine according to the present invention.

2 is a cross-sectional view showing a head bolt equipped with a sensor according to the present invention.

3 is a plan view from above of the head bolt of FIG. 2;

4 is a cross-sectional view of the head bolt of FIG.

<Explanation of symbols for the main parts of the drawings>

10: cylinder head 12: cylinder block

14: piston 20: head bolt

22: head bolt head 23: insertion hole

24: upper head bolt 26: lower head bolt

30: combustion pressure sensor 32: optical fiber

34: ring 40: through hole

42: tab 44: fluid space

Hereinafter, the engine mounting structure of the sensor according to the present invention will be described in detail with reference to the accompanying drawings.

1 shows a state in which a combustion pressure sensor is mounted on an engine according to the present invention. In general, the engine consists of a cylinder head 10 forming the upper portion of the cylinder, a cylinder block 12 forming the body of the cylinder, a piston 14 reciprocating up and down within the cylinder, and other components. The piston 14 is also provided with a plurality of piston rings 16 at predetermined positions to maintain the airtightness between the cylinder block 12 and the piston 14 or to scrape off the lubricating oil attached to the inner wall of the cylinder.

In general, a plurality of head bolts 20 are installed in the cylinder head 10 to couple with the cylinder block 12. The head bolt 20 penetrates up and down at the end of the cylinder head 10 and is screwed to a part of the cylinder block 12.

In the present invention, a sensor for measuring the combustion pressure inside the engine is installed in the head bolt (20). To this end, an insertion hole 23 is formed in the head bolt 20 at a predetermined depth in the vertical direction, and the combustion pressure sensor 30 is inserted into the insertion hole 23.

Combustion pressure sensor 30 for measuring the combustion pressure can be used both a piezoelectric type or a sensor using an optical fiber, in the present invention, a high sensitivity is provided with a diaphragm suitable for insertion into the insertion hole 23 formed in the head bolt 20 Fiber optic pressure sensors are particularly suitable. In the case of using a sensor using an optical fiber, it is easy to insert into the head bolt 20 because of its small size, and is resistant to external temperature and vibration and economically inexpensive.

Combustion pressure sensor 30 is inserted into the head bolt 20, one end is through the inside of the cylinder and a predetermined method to detect the pressure in the cylinder, the other end is connected to the external measuring device by the optical fiber 32 do.

The cylinder block 12 is formed with a through hole 40 in consideration of the location where the combustion pressure sensor 30 in the head bolt 20 is located. The through hole 40 passes through the lower end of the combustion pressure sensor 30, and a flow space 44 corresponding to the through hole 40 is formed in the head bolt 20 so that the pressure inside the cylinder is transferred to the combustion pressure sensor 30. It is configured to be delivered.

If the diameter 40 is too large, the gas in the cylinder may flow out, and if the diameter is too small, the flow of the gas toward the combustion pressure sensor 30 is not free, so it is not suitable for measuring an accurate pressure value. It is preferable that it is about 2-3 mm.

2 is a cross-sectional view showing the head bolt of the present invention. 1 and 2, the head bolt 20 includes a polygonal head 22, an upper head bolt 24 positioned between the head 22 and the flow space 44, and a flow space. It consists of a head bolt lower portion 26 positioned below 44. Since the combustion pressure sensor 30 is located directly above the flow space 44, an insertion hole 23 for the combustion pressure sensor 30 is formed only in the upper head bolt 24, and in the lower part 26 of the head bolt. Not formed.

The head bolt 20 is provided with a tab 42 on the thread of the point where it meets the through-hole 40, the tab 42 is a flow space 44 for the gas in the cylinder flows to the combustion pressure sensor 30 by the tab 42 Form.

At this time, the combustion gas of the cylinder moved to the combustion pressure sensor 30 through the through hole 40 and the flow space 44 is near the edge of the combustion pressure sensor 30 through the insertion hole 23 of the head bolt 20. There is a risk of leakage. In order to prevent this, a ring 34 may be provided to prevent leakage of pressure at a predetermined position of the combustion pressure sensor 30. The ring 34 preferably has an O-shape. In the present invention, the ring 34 is provided at an upper end of the combustion pressure sensor 30 as an example.

3 is a view from above of the head bolt 20 used in the present invention. Referring to the drawings, the head portion 22 of the head bolt 20 has a hexagonal shape is configured to easily apply a force when detaching, insertion hole for inserting the combustion pressure sensor 30 in the central position is formed I can see that there is.

4 is a cross-sectional view of the head bolt 20 shown in FIG. 2 taken along the line II, in which the flow space 44 is formed, and the combustion pressure sensor 30 is not installed for convenience. . Referring to the drawings, an insertion hole 23 for inserting and coupling the combustion pressure sensor 30 is formed in the center of the head bolt 20, and the tab 42 is formed along the outer circumferential surface of which the thread is formed. ) Was formed. In addition, the flow space 44 is provided toward the insertion hole 23 position in which the combustion pressure sensor 30 is installed, and the combustion pressure sensor in which the gas in the cylinder flowing through the through hole 40 is installed in the insertion hole 23. It is comprised so that it may move to 30 appropriately.

Looking at the installation process and operation of the engine mounting structure of the sensor according to the present invention configured as described above are as follows.

First, in order to install the combustion pressure sensor 30 in the engine, the combustion pressure sensor 30 is inserted into the head bolt 20 provided with the insertion hole 23 made in advance so as to be positioned directly above the flow space 44. Then, the head bolt 20 is screwed to couple the cylinder head 10 and the cylinder block 12. The head bolt 20 is a flow formed in the through-hole 40 and the head bolt 20 formed in the cylinder head 10 in a state in which the cylinder head 10 and the cylinder block 12 are sufficiently coupled, that is, the cylinder is completely sealed. Since the spaces 44 are designed to be precisely connected to each other, the process of installing the combustion pressure sensor 30 is completed by coupling the head bolts 20.

In order to replace the combustion pressure sensor 30 installed in this way, only by releasing the screwing of the head bolt 20 to replace the combustion pressure sensor 30 in the insertion hole 23, the head bolt 20 is placed on the top. Recombine them as described. Therefore, there is no need to manipulate other parts of the engine or to consider other correlations in the installation and replacement of the sensor, the present invention can be very easy, simple and quick to install and replace the sensor.

The combustion pressure sensor 30 installed in the above manner receives the pressure inside the cylinder as it is through the through hole 40 installed in the cylinder head 10 and the flow space 44 installed in the head bolt 20. The data related to the combustion pressure of the cylinder is sent along the optical fiber 32 connected to the 30 to an external measuring device.

The engine mounting structure of the sensor according to the present invention configured as described above has the advantage that not only the structure is simple but also easy to install and replace by installing the combustion pressure sensor in the head bolt, thereby minimizing damage due to breakage of components.

In addition, since the combustion pressure sensor is installed in the head bolt, there is little risk of damage due to external shocks, and the pressure inside the cylinder is directly transmitted to the combustion pressure sensor along the flow space formed in the through hole and the head bolt installed in the cylinder head. Combustion pressure can be measured.

Furthermore, by installing a ring on the combustion pressure sensor, it is possible to prevent the pressure of the cylinder from leaking to the outside, and the optical fiber pressure sensor can be used to achieve the miniaturization of the structure as well as to reduce the part price.

Although only embodiments of the present invention have been described in detail herein, it will be apparent to those skilled in the art that various modifications and changes can be made in the illustrated structures without departing from the spirit and scope of the invention. Accordingly, the invention should only be assessed by the appended claims.

Claims (7)

In the structure for mounting the combustion pressure sensor to the engine formed of the cylinder head, cylinder block and piston, A head bolt for coupling the cylinder head to the cylinder block, The engine mounting structure of the sensor, characterized in that the combustion head sensor is inserted into the head bolt for detecting the state of the engine. The engine mounting structure of claim 1, wherein the cylinder head has a through hole connecting the inside of the cylinder and the combustion pressure sensor to a position corresponding to the combustion pressure sensor. 3. The head bolt of claim 2, wherein the head bolt has a tab formed at a position of a screw thread in contact with the through hole, wherein the tab forms a flow space for the pressure in the cylinder to flow from the through hole to the combustion pressure sensor. Engine mounting structure of the sensor. 4. The engine mounting structure of claim 3, wherein the head bolt is formed with an insertion hole for inserting the combustion pressure sensor into an upper side of the tab and is blocked below the tab. 5. The engine mounting structure of claim 4, wherein the combustion pressure sensor is positioned above the flow space formed by the tab and is connected to the outside by an optical fiber through an insertion hole of the head bolt. 2. The engine mounting structure of claim 1, wherein the head bolt has a ring on the edge of the combustion pressure sensor to prevent leakage of the pressure of the cylinder. 2. The engine mounting structure of claim 1, wherein the combustion pressure sensor is a high sensitivity optical fiber pressure sensor.