KR20110049153A - Air volume control device for cng engine - Google Patents

Abstract

PURPOSE: An air volume control device of a CNG(Compressed Natural Gas) engine is provided to reduce the resistance against exhaust gas because a valve plate is arranged not to obstruct the flow of the exhaust gas. CONSTITUTION: An air volume control device of a CNG engine comprises an actuator. The actuator includes an actuator valve(100), a valve housing(170) in which a valve rod(130) is inserted so that a valve plate(140) reciprocates to an exhaust line(200) to bypass the exhaust gas passing through the exhaust line to outside, an actuator housing(110) which forces the valve rod to move from side to side and is embedded with an elastic member(111) and a diaphragm(112), and a fixing bracket(121) which connects the valve housing and the actuator housing.

Description

Air volume control device of CNC engine {AIR VOLUME CONTROL DEVICE FOR CNG ENGINE}

The present invention relates to an air volume control device of a CNG engine, and more particularly, to an air amount control device that can increase the overall performance of an intake and exhaust system of a CNG engine by controlling exhaust gas supplied to a turbine of a turbocharger device with an external actuator. It is about.

In general, CNG engine is a compressed natural gas (Compressed Natural Gas) as the main raw material, the compressed natural gas has the advantages of higher combustion efficiency and less emission of pollutants than gasoline or diesel.

The CNG engine is provided with a turbocharger system that supplies air to the engine at a pressure higher than atmospheric pressure to fill a large amount of air into the engine, thereby increasing the fuel injection amount and thus improving the output of the engine.

Although the turbocharger system is not shown, a compressor and an intercooler are sequentially installed in an intake line supplied to the CNG engine, and the compressor is connected to a turbine mounted on an exhaust line of the CNG engine to rotate simultaneously with the rotary shaft of the turbine. .

In other words, the exhaust gas discharged from the exhaust line rotates the turbine, and as the turbine rotates, the compressor mounted on the intake line rotates and simultaneously compresses the air sucked by the compressor mounted on the intake line, thereby increasing the density of the air. By passing it, the intake air is oversupplied into the CNG engine.

In addition, the CNG engine maintains a constant air-fuel ratio and changes the output by the amount of air, and thus requires fine air amount control in the entire RPM region.

In order to control the amount of air, the exhaust line directly discharges the exhaust gas instead of through the turbine to prevent excessive intake pressure due to the change in intake pressure measured by the intake pressure sensor mounted on the final intake line of the CNG engine. A gate gate line is provided.

The west gate line is equipped with a waste gate valve that is controlled by an electronic control unit (ECU) according to a change in intake pressure sensed by the intake pressure sensor to open and close the waste gate line.

That is, when the intake pressure sensor detects that the intake pressure of the intake line is excessively high, the detected signal is transmitted to the electronic controller, and the waste gate valve is operated by the electronic controller to open the waste gate line to exhaust the exhaust gas. By discharging the gas so as not to operate the turbine, the intake pressure supplied to the intake line and the exhaust pressure exhausted accordingly can be adjusted.

That is, referring to FIG. 4 and FIG. 5, a disk-shaped valve plate 22 for bypassing the exhaust gas of the exhaust line 30 is formed at the end of the valve rod 20 operated by the actuator 10.

Here, when the valve rod 22 is pulled or pushed by the elastic member 14 and the diaphragm 16 disposed inside the actuator housing 12, the valve plate 22 controls whether the exhaust gas is bypassed. Done.

That is, FIG. 4 shows a state in which the valve plate 22 is closed, inducing the flow of exhaust gas through the turbine 40.

In addition, FIG. 5 shows that the valve plate 20 is open, and indicates that the exhaust gas is diverted by bypassing the turbine 40 by inducing exhaust gas to pass through the bypass pipe 32.

At this time, since the exhaust gas enters into the valve housing 60 via the bypass pipe 32, leakage of exhaust gas occurs through a gap between the valve housing 60 and the valve rod 20. do.

In addition, the exhaust external actuator according to the prior art as described above, the ECU sends a signal to open or close the solenoid valve to match the target air volume, and the valve plate 22 is repeatedly opened and closed by such a signal, such valve plate ( The wear of the valve seat 50 in contact with 22 is intensified.

In addition, when the valve plate 22 is opened, the exhaust gas is discharged while directly contacting the valve plate 22 in the process of passing through the valve housing 60, so that the valve plate 22 is It not only increases the temperature of the exhaust gas around it, but also increases the size of the actuator to withstand such deterioration, which causes cost increase.

Therefore, the present invention was created to solve the above problems, the object of the present invention is to operate the valve mounted on the turbine side by a direct external actuator to increase the durability of the valve, excellent fuel economy and CNG engine It is to provide an air volume control device of the CNG engine to stably control the amount of air sucked into the air.

The air volume control device of the CNG engine according to an embodiment of the present invention for achieving this object is provided with an actuator for controlling the amount of air flowing into the CNG engine through the exhaust line to selectively enter the valve housing through the bypass pipe In the air volume control device, the actuator is a valve housing, the valve is inserted into the valve rod which is opened and closed to bypass the exhaust gas passing through the exhaust line by reciprocating the valve plate in the exhaust line connected to the turbine of the CNG engine and the turbocharger And an actuator housing for moving the valve rod from side to side by applying a force to the rod, and a fixing bracket for connecting the valve housing and the actuator housing.

In addition, the actuator housing,

An elastic member and a diaphragm are built in the actuator housing,

One end is supported by the elastic member and the other end includes a rod connecting means coupled to the valve rod.

In addition, the valve housing includes a valve rod formed of a valve plate at one end thereof selectively opening and closing the bypass passage, and at the same time, the valve rod is inserted through the valve housing and is formed to surround the outer circumferential surface of the valve rod. It characterized in that it comprises a guide.

In addition, the cross-sectional shape of the fixing bracket connecting the valve housing and the actuator housing is characterized in that formed in the '' 'shape.

In addition, one end of the valve housing is characterized in that it has a seating surface in contact with the valve plate formed on the valve rod end when the bypass passage is opened.

In addition, the rod connecting means is provided with a thread on the outer peripheral surface, characterized in that it comprises a valve position adjusting member for adjusting the separation distance from the end of the valve rod by rotating along this thread.

In addition, an insertion groove is formed at one end of the valve rod, and the end of the rod connecting means is inserted into the insertion groove.

In addition, the valve position adjustment member is fixed to the end of the insertion groove is characterized in that it further comprises.

In addition, a screw thread is formed on an outer circumferential surface of the rod connecting means, and the valve position adjusting member is engaged with the thread, and the length of the rod connecting means is adjusted according to the rotation of the valve position adjusting member.

As described above, according to the air amount controlling apparatus according to the embodiment of the present invention, the valve plate is disposed in a position which does not disturb the flow of the exhaust gas in the exhaust line, thereby reducing the resistance to the exhaust gas.

In addition, the valve seat is omitted and the control method is changed to prevent wear of the valve seat.

In addition, since the valve guide is press-fitted, it has an effect of preventing leakage of exhaust gas.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the turbocharger system of the CNG engine includes an intake line for supplying intake air supplied to the CNG engine, an exhaust line for discharging exhaust gas combusted by the CNG engine, and the exhaust line mounted on the exhaust line. The compressor is mounted on the turbine and the intake line rotating at high speed by the exhaust gas, and is connected to the same rotation axis as the rotation axis of the turbine and rotates by the rotation of the turbine to make intake air into high temperature and high pressure air and supply it to the combustion chamber. It is composed.

In other words, the exhaust gas generated by the combustion of fuel in the CNG engine is supplied to the turbine via the exhaust line to rotate the turbine.

When the turbine rotates, the compressor connected to the same rotary shaft rotates to compress the air sucked into the CNG engine through the intake line, thereby increasing the density of the air and supplying it into the CNG engine.

Since the air passing through the compressor has a high temperature of 100 ° C., an intercooler is provided between the compressor and the CNG engine to lower the temperature of the air to further increase the density of the air.

As the air passed through the intercooler is lowered to about 50 ° C., the density thereof is further increased to increase the amount of air supplied into the CNG engine.

The biggest feature of the present invention is to install a valve member that is opened and closed in a linear reciprocating movement in the exhaust line connected to the turbine in the CNG engine, the valve member is linked to the external actuator 100 is operated in a linear reciprocating motion.

In addition, the external actuator 100 may be connected to the electronic control unit (ECU) to operate when the control static pressure is applied from the electronic control unit (ECU).

Figure 2 shows a closed state of the valve plate of the air volume control device of the CNG engine according to an embodiment of the present invention.

As shown in FIG. 2, the external actuator 100 includes an elastic member 111 and a diaphragm 112 inside the actuator housing 110.

The rod connecting means 120 is elastically supported by the elastic member 111.

The rod connecting means 120 is coupled to the fixing bracket 121 by an actuator rod 113 fitted to the outer circumferential surface.

As shown in Figure 2, the fixing bracket 121, it is preferable to form the cross-section '' 'shape. At this time, the shape of the fixing bracket 121 may be any shape as long as the rod connecting means 120 has a space that can secure the moving distance to move left and right on the drawing.

In this case, the diaphragm 112 is generally formed of a rubber material, and at the same time as the reciprocating motion of the diaphragm 112, the rod connecting means 120 is formed to enable the reciprocating motion integrally.

In addition, a thread is formed on the outer circumferential surface of the rod connecting means 120.

A valve rod 130 having a valve plate 140 is connected to an end of the rod connecting means 120.

The valve plate 140 is located inside the valve housing 170, and the valve housing 170 is in communication with a passage that bypasses the flow of fluid to the outside.

Here, a seating surface 180 is formed on a surface of the valve plate 140 that contacts the valve housing 170 when the valve plate 140 is closed.

The seat surface 180 may be applied to any material that can absorb the shock and noise generated when opening and closing the valve plate 140.

An insertion groove 141 is formed at an end of the valve rod 130 toward the rod connecting means 120, and an end of the rod connecting means 120 is inserted into the insertion groove 141.

In addition, the end of the insertion groove 141 is formed with a valve position adjusting member 122 having a screw thread on the inner peripheral surface to be engaged with the screw thread of the rod connecting means 120.

As the rod connecting means 120 is rotated according to the rotation of the valve position adjusting member 122, the inside of the insertion groove 141 is moved.

That is, the length of the rod connecting means 120 is moved by the valve position adjusting member 122 in the insertion groove 141 and the length thereof is changed, thereby the valve rod 130 and the valve plate 140. ) To adjust the length.

In addition, the valve guide 150 is press-fitted to the outer circumferential surface of the valve rod 130.

The valve guide 150 serves to prevent leakage of the exhaust gas.

In addition, a valve body 160 surrounding the outer circumferential surface of the valve guide 150 is formed.

Thus, the valve plate 140 opens and closes the bypass pipe 210 branched from the exhaust line 200.

In this case, referring to FIG. 2, when pressure is applied by the diaphragm 112, the bypass pipe 210 overcomes the elastic force of the elastic member 111 and pushes the valve plate 140 to the right in the drawing. ) Will be closed.

Therefore, the exhaust gas passes through the turbine 300, thereby inducing a rotational movement of the turbine 300.

Meanwhile, referring to FIG. 3, when the pressure is reduced by the diaphragm 112, the valve plate 140 is pushed to the left side in the drawing by the elastic restoring force of the elastic member 111. ) Is opened.

At this time, part of the exhaust gas is discharged directly via the valve plate 140 without passing through the turbine 300.

As described above, when a part of the exhaust gas is directly discharged when the valve plate 140 is opened, the engine is prevented from being misfired when more air is required as the air-fuel ratio control engine of the engine.

In other words, the output control of the CNG engine basically makes the amount of air required for the output in the ECU and controls it to match the value of the air set in the turbo. This control is operated from time to time to match the air volume value.

Therefore, as described above, the actuator 100 operates when the turbine wheel exceeds the limit speed of the turbine wheel to control the speed of the turbine through the control of the valve plate 140, thereby preventing the maximum speed of the turbo from occurring.

In addition, by placing the valve plate 140 in a position which does not disturb the flow of the exhaust gas in the exhaust line 200 to reduce the resistance to the exhaust gas.

In addition, the valve seat is omitted and the control method is changed to prevent wear of the valve seat.

In addition, since the valve guide 150 is press-fitted, leakage of exhaust gas is prevented.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and easily changed and equalized by those skilled in the art from the embodiments of the present invention. It includes all changes to the extent deemed acceptable.

Figure 1 schematically shows the overall configuration of the air amount control apparatus according to an embodiment of the present invention.

2 is a cross-sectional view showing a state in which the valve plate of the actuator applied to the air amount control apparatus according to an embodiment of the present invention is closed.

3 is a cross-sectional view showing an open state of the valve plate of the actuator applied to the air amount control apparatus according to an embodiment of the present invention.

4 is a cross-sectional view showing an open state of a valve plate of an actuator according to the prior art.

5 is a cross-sectional view showing a state in which the valve plate of the actuator according to the prior art is closed.

* Explanation of Major Parts Used in Drawings *

100: actuator 110: actuator housing

111: elastic member 112: diaphragm

113: actuator rod 120: rod connecting means

121: fixing bracket 122: valve position adjustment member

130: valve rod 140: valve plate

141: insertion groove 150: valve guide

160: valve body 170: valve housing

180: seating surface 200: exhaust line

210: bypass tube 300: turbine

Claims (9)

An air volume control device having an actuator for controlling the amount of air flowing into a CNG engine through an exhaust line to selectively enter the valve housing through a bypass pipe, The actuator is a valve housing in which a valve rod is inserted and opened to bypass the exhaust gas passing through the exhaust line by reciprocating the valve plate in an exhaust line connected to the turbine of the CNG engine and the turbocharger. An airflow control device of a CNG engine including an actuator housing for moving a rod from side to side and a fixing bracket connecting a valve housing and an actuator housing. The method of claim 1, The actuator housing, An elastic member and a diaphragm are built in the actuator housing, Rod connecting means having one end supported by the elastic member and the other end engaged with the valve rod; CNG engine air volume control device comprising a. The method of claim 1, The valve housing includes a valve rod formed of a valve plate at one end thereof selectively opening and closing the bypass passage, and at the same time, the valve rod is inserted through the valve housing. CNG engine air amount control device including a valve guide formed to surround the outer peripheral surface of the valve rod. The method of claim 1, The air flow control device of the CNG engine, characterized in that the cross-sectional shape of the fixing bracket connecting the valve housing and the actuator housing is formed in the '' 'shape. The method of claim 1, And one end portion of the valve housing has a left surface which is in contact with a valve plate formed at an end portion of the valve rod when the bypass passage is opened. The method of claim 2, The rod connecting means has a thread on the outer circumferential surface, and rotates along the thread, the air flow amount control device of the CNG engine, characterized in that it comprises a valve position adjusting member for adjusting the separation distance from the end of the valve rod. The method of claim 1, An insertion groove is formed at one end of the valve rod, and an end portion of the rod connecting means is inserted into the insertion groove. The method of claim 2, The air volume control device of the CNG engine, characterized in that it further comprises a valve position adjustment member is fixed to the end of the insertion groove rotates. The method of claim 2, A thread is formed on the outer circumferential surface of the rod connecting means, and the valve position adjusting member is engaged with the thread, and the length of the rod connecting means is adjusted according to the rotation of the valve position adjusting member. Device.

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