CN111441997A - Natural gas engine anti-surge system - Google Patents

Abstract

The invention discloses an anti-surge system for a natural gas engine, comprising an exhaust manifold, an ERG cooler, an intercooler, a compressor and a throttle valve, and is characterized in that it includes a communication intercooler, an ERG cooler and an exhaust manifold. The first anti-surge passage is provided with a first solenoid valve; when the throttle valve opening is reduced, the first solenoid valve is opened, the first anti-surge passage is opened, and the compressor and the throttle valve are led out. between compressed air to the exhaust manifold. The method of exporting the compressed air between the compressor and the throttle valve of the invention effectively utilizes the energy of the extracted compressed air and improves the efficiency of the turbocharger while preventing surges; the present invention can play a role in the full working condition of the engine; The present invention reduces exhaust manifold temperature while avoiding surge.

Description

A natural gas engine anti-surge system

technical field

The invention belongs to the technical field of engines, in particular to an anti-surge system for a natural gas engine.

Background technique

When the vehicle decelerates, the throttle valve opening of the natural gas engine decreases, and the gas pressure before the throttle valve is higher than the gas pressure at the compressor outlet, and the gas flows back after the compressor, causing the turbocharger to surge.

Chinese Patent "Turbocharged Anti-Surge System", Announcement No. CN104832221B, Announcement Date 2016.04.27, discloses a turbocharged anti-surge system, which includes: a turbocharger device with a turbine and a compressor that communicate with each other ; The first intake pipe, one end is connected to the exhaust port of the internal combustion engine; the mixed flow device is connected to the other end of the first intake pipe and is connected to the turbine of the turbocharger; the first outlet pipe, one end is connected to the compressor of the turbocharger, the other One end is connected to the air inlet of the internal combustion engine; the second air outlet is connected to the compressor of the turbocharging device at one end; the heat exchange device is used for heat exchange with the internal combustion engine; At one end, the outlet is communicated with the heat exchange device; and the second air inlet pipe is communicated with the heat exchange device at one end and communicated with the mixed flow device at the other end. The patent is to introduce the compressed gas between the compressor and the throttle valve into the exhaust manifold to avoid surge, but it cannot play a role in the full range of engine operating conditions. It can work when the compressed gas pressure between the compressor and the throttle valve is higher than the exhaust manifold pressure, but it cannot work when the compressed gas pressure between the compressor and the throttle valve is lower than the exhaust manifold pressure. Play a role.

Chinese patent "An Engine Turbocharged Air Intake System", publication number CN204783371U, published on 2015.11.18, discloses an engine turbocharged air intake system, including an air filter outlet steel pipe joint connected to the air intake side of a supercharger , and the intercooler outlet steel pipe joint connected to the exhaust side of the supercharger, and an anti-surge pipeline is also provided, the anti-surge pipeline includes an anti-surge valve, and the anti-surge valve is three The first passage of the anti-surge valve is connected to the outlet steel pipe joint of the intercooler, the second passage of the anti-surge valve is connected to the outlet steel pipe joint of the air filter, and the anti-surge valve is connected to the outlet pipe joint of the air filter. The third passage is connected to the intake cylinder of the engine, and the airflow enters the anti-surge valve from the first passage and flows through the second passage, respectively, into the air filter outlet steel pipe joint, and flows through the third passage. When entering the intake cylinder, using the above technical solution, when the vehicle decelerates, the large pressure difference between the intake and exhaust sides of the supercharger can be discharged, so as to avoid the wear and fatigue of the supercharger and prolong its service life. In this patent, the compressed gas between the compressor and the throttle valve is introduced into the compressor to avoid surge. Its main disadvantage is the reduced efficiency of the turbocharger. Exporting the compressed gas between the compressor and the throttle valve avoids turbocharger surge, but the energy of the compressed gas is not utilized.

SUMMARY OF THE INVENTION

Aiming at the problems existing in the background technology, the purpose of the present invention is to provide a natural gas engine protection device that can not only avoid the surge of the turbocharger, but also utilize the energy of the compressed gas between the compressor and the throttle valve, and can also play a role in all working conditions. Surge system.

In order to achieve the above object, the natural gas engine anti-surge system designed by the present invention includes an exhaust manifold, an ERG cooler, an intercooler, a compressor and a throttle valve, and is characterized in that: it includes a communication intercooler, an ERG cooler and The first anti-surge passage of the exhaust manifold, the first anti-surge passage is provided with a first solenoid valve; when the throttle valve opening is reduced, the first solenoid valve is opened, the first anti-surge passage is opened, and the compressed air is exported Compresses the gas between the engine and the throttle valve to the exhaust manifold.

Preferably, the first anti-surge passage and the part in the cooler via the ERG are independent passages.

Preferably, a first pipeline is provided between the intercooler and the ERG cooler, and a second pipeline is provided between the ERG cooler and the exhaust manifold.

Further preferably, the first solenoid valve is located on the first pipeline.

In order to further suppress the surge, as a preferred solution, it also includes: a second anti-surge passage that communicates with the ERG cooler, the intercooler and the compressor; the second anti-surge passage is provided with a second solenoid valve; Solenoid valve and the second solenoid valve; the exhaust gas is led out to the front of the compressor through the ERG cooler and the intercooler through the second anti-surge passage.

Preferably, the second anti-surge passage and the part passing through the intercooler are independent passages.

Preferably, a third pipeline is provided between the intercooler and the compressor, and a fourth pipeline is further provided between the intercooler and the ERG cooler.

Further preferably, the second solenoid valve is located on the third pipeline.

The beneficial effects of the present invention are as follows: the method of exporting the compressed air between the compressor and the throttle valve of the present invention prevents surge, and at the same time effectively utilizes the energy of the extracted compressed air, thereby improving the efficiency of the turbocharger; It works within a range of operating conditions; the present invention reduces exhaust manifold temperature while avoiding surge.

Description of drawings

Fig. 1 is the structural representation of the present invention, wherein: the thick solid line with arrow is high temperature gas pipeline, the thin solid line with arrow is low temperature gas pipeline, the dotted line with arrow is anti-surge pipeline, the arrow indicates the gas pipeline Flow direction.

In the figure: 1 first solenoid valve, 2 second solenoid valve, 3 EGR cooler, 4 intercooler, 5 turbine, 6 compressor, 7 EGR valve, 8 throttle valve, 9 mixer, 10 exhaust manifold, first The pipeline 11 , the second pipeline 12 , the third pipeline 13 , and the fourth pipeline 14 .

Detailed ways

The technical solutions (including the preferred technical solutions) of the present invention will be further described in detail below by referring to FIG. 1 and by enumerating some optional embodiments of the present invention. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The exhaust gas of the natural gas engine is divided into two paths from the exhaust manifold 10 , one path flows into the turbine 5 to do work, and the other path is cooled by the EGR cooler 3 and then enters the mixer 9 through the EGR valve 7 . The air enters the compressor 6 from the atmosphere through an air filter (not shown) to be pressurized, and after being cooled by the intercooler 4 , passes through the throttle valve 8 and enters the mixer 9 . The fresh air is mixed with the recirculated exhaust gas in the mixer 9 and then enters the engine through an intake manifold (not shown). This part belongs to the prior art and will not be repeated here. When the vehicle decelerates, the opening degree of the throttle valve 8 of the natural gas engine decreases, and the phenomenon that the gas pressure at the inlet of the throttle valve 8 is higher than the gas pressure at the outlet of the compressor 6 occurs. If the engine operates in a region with limited surge margin, such as a low-speed and high-load region, the phenomenon that the gas pressure at the inlet of the throttle valve 8 is higher than the gas pressure at the outlet of the compressor 6 will induce the compressor 6 to surge.

As shown in FIG. 1 , in the natural gas engine anti-surge system designed by the present invention, a first pipeline 11 is provided between the intercooler 4 and the ERG cooler 3 , and a first pipeline 11 is provided between the ERG cooler 3 and the exhaust manifold 10 . The second pipeline 12, the first solenoid valve 1 is arranged on the first pipeline 1; the third pipeline 13 is arranged between the intercooler 4 and the compressor 6, and between the intercooler 4 and the ERG cooler 3 A fourth pipeline 14 is provided;

Both the first pipeline 11 and the second pipeline 12 communicate with the ERG cooler 3 to form a first anti-surge passage, and they are independent from the previous high-temperature gas passages flowing into the ERG cooler 3 . That is, the ERG cooler 3 has two independent passages. Both the third pipeline 13 and the fourth pipeline 14 communicate with the intercooler 3 to form a second anti-surge passage, and they are independent from the passage of the charged air entering the intercooler 4 . That is, the intercooler 4 has two independent passages. The first anti-surge passage and the second anti-surge passage are also independent of each other.

When the opening degree of the throttle valve 8 of the natural gas engine decreases, the first solenoid valve 1 and the second solenoid valve 2 will be opened simultaneously.

After the first solenoid valve 1 is opened, the gas between the compressor 6 and the throttle valve 8 first passes through the first solenoid valve 1, then enters the EGR cooler 3 for heating, and finally enters the exhaust manifold 10 (natural gas engine anti-surge system usually It works in the low-speed and large-load region where the surge margin is limited, and at this time, the gas pressure between the compressor 6 and the throttle valve 8 is generally higher than the pressure of the exhaust manifold 10). The gas between the compressor 6 and the throttle valve 8 is led to the exhaust manifold 10 , on the one hand, the compressor surge is prevented, and on the other hand, the temperature of the exhaust manifold 10 is lowered.

After the second solenoid valve 2 is opened, a part of the exhaust gas cooled by the EGR cooler 3 from the exhaust manifold 10 enters the mixer 9 through the EGR valve 7 , and the other part enters the mixer 9 through the EGR valve 7 after being cooled by the intercooler 4 , and enters through the solenoid valve 2 Compressor 6 inlet. The exhaust gas of the exhaust manifold 10 is led to the inlet of the compressor 6. First, the pressure ratio of the outlet gas to the inlet gas of the compressor 6 is reduced to prevent surge; The gas between the compressor 6 and the throttle valve 8 is led to the exhaust manifold 10; finally, the exhaust energy of the exhaust manifold 10 is reduced, on the one hand, the power of the supercharger is reduced, and with the reduction of the power of the supercharger , the pressure ratio of the outlet gas to the inlet gas of the compressor 6 is also lowered, and on the other hand, the temperature of the exhaust manifold 10 is lowered.

The purpose of exporting the compressed gas between the compressor 6 and the throttle valve 8 is to avoid surge. The main purpose of exporting the exhaust gas is to reduce the pressure of the exhaust manifold 10, so that the compressed gas between the compressor 6 and the throttle valve 8 can enter the exhaust manifold. The secondary purpose is to increase the inlet pressure of the compressor 6 and reduce the pressure ratio of the compressor 6. , suppressing the surge, and in addition, it can also play a role in reducing the temperature of the exhaust manifold 10 . The compressed gas between the compressor 6 and the throttle valve 8 is introduced into the exhaust manifold 10 to compensate for the energy loss caused by the exhaust gas being exported, and at the same time, the temperature of the exhaust manifold is reduced.

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, combination, replacement, improvement, etc. made under the spirit and principle of the present invention are included in the within the protection scope of the present invention.

Claims (8)

1. The natural gas engine anti-surge system comprises an exhaust manifold, an ERG cooler, an intercooler, a compressor and a throttle valve, and is characterized in that: the surge protection device comprises a first surge protection passage communicated with an intercooler, an ERG cooler and an exhaust manifold, wherein a first electromagnetic valve is arranged on the first surge protection passage; when the opening degree of the throttle valve is reduced, the first electromagnetic valve is opened, the first anti-surge passage is opened, and compressed gas between the compressor and the throttle valve is led out to the exhaust manifold.

2. The gas engine anti-surge system according to claim 1, wherein: the first surge-proof passage, and the portion passing through the ERG cooler are independent passages.

3. The gas engine anti-surge system according to claim 1 or 2, characterized in that: a first pipeline is arranged between the intercooler and the ERG cooler, and a second pipeline is arranged between the ERG cooler and the exhaust manifold.

4. The gas engine anti-surge system according to claim 3, characterized in that: the first electromagnetic valve is positioned on the first pipeline.

5. The gas engine anti-surge system according to claim 1 or 2, characterized in that: further comprising: a second surge-proof passage for communicating the ERG cooler, the intercooler and the compressor; a second electromagnetic valve is arranged on the second surge-proof passage; simultaneously opening the first electromagnetic valve and the second electromagnetic valve; the second surge-proof passage leads the exhaust gas out to the front of the compressor through the ERG cooler and the intercooler.

6. The gas engine anti-surge system according to claim 5, wherein: the second surge-preventing passage and a portion passing through the intercooler are independent passage lines.

7. The gas engine anti-surge system according to claim 5, wherein: and a third pipeline is arranged between the intercooler and the compressor, and a fourth pipeline is also arranged between the intercooler and the ERG cooler.

8. The gas engine anti-surge system according to claim 6 or 7, characterized in that: the second electromagnetic valve is positioned on the third pipeline.

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