阅读说明：本技术 一种天然气发动机防喘振系统 (Natural gas engine anti-surge system ) 是由 刘夏 邹振义 张沈欢 张磊 于 2020-04-19 设计创作，主要内容包括：本发明公开一种天然气发动机防喘振系统,包括排气歧管、ERG冷却器、中冷器、压气机和节气门,其特征在于：包括连通中冷器、ERG冷却器和排气歧管的第一防喘通路,所述第一防喘通路上设有第一电磁阀；当节气门开度减小时,开启第一电磁阀,将第一防喘通路开启,导出压气机与节气门间压缩气体至排气歧管。本发明将压气机与节气门间压缩空气导出的方式防喘振的同时有效利用了被导出压缩空气的能量,提高了涡轮增压器效率；本发明可在发动机全工况范围内发挥作用；本发明在避免喘振的同时降低了排气歧管温度。(The invention discloses a natural gas engine anti-surge system, which comprises an exhaust manifold, an ERG cooler, an intercooler, a gas 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. The invention prevents surge in a mode of guiding out the compressed air between the air compressor and the air throttle, effectively utilizes the energy of the guided out compressed air, and improves the efficiency of the turbocharger; the invention can play a role in the full working condition range of the engine; the invention reduces exhaust manifold temperature while avoiding surge.)

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.

Technical Field

The invention belongs to the technical field of engines, and particularly relates to an anti-surge system of a natural gas engine.

Background

When the vehicle decelerates, the opening of a throttle valve of the natural gas engine is reduced, the phenomenon that the gas pressure in front of the throttle valve is higher than the gas pressure at the outlet of the gas compressor occurs, and the gas behind the gas compressor flows back to trigger the surge of the turbocharger.

Chinese patent "turbocharging anti-surge system", No. CN104832221B, bulletin day 2016.04.27 discloses a turbocharging anti-surge system, which includes: the turbocharger device is provided with a turbine and a compressor which are communicated with each other; one end of the first air inlet pipe is communicated with an exhaust port of the internal combustion engine; the mixed flow device is communicated with the other end of the first air inlet pipe and is communicated with a turbine of the turbocharging device; one end of the first air outlet pipe is communicated with a compressor of the turbocharging device, and the other end of the first air outlet pipe is communicated with an air inlet of the internal combustion engine; one end of the second air outlet pipe is communicated with the compressor of the turbocharging device; a heat exchange device for exchanging heat with the internal combustion engine; the flow divider is provided with an inlet and an outlet, the inlet is communicated with the other end of the second air outlet pipe, and the outlet is communicated with the heat exchange device; and one end of the second air inlet pipe is communicated with the heat exchange device, and the other end of the second air inlet pipe is communicated with the mixed flow device. The patent is to introduce compressed gas between the compressor and the throttle into the exhaust manifold to avoid surge, but it does not function over the full operating range of the engine. The air compressor can play a role under the working condition that the pressure of compressed air between the air compressor and the air throttle is higher than the pressure of the exhaust manifold, but cannot play a role under the working condition that the pressure of the compressed air between the air compressor and the air throttle is lower than the pressure of the exhaust manifold.

China patent 'an engine turbocharging air intake system', publication number CN204783371U, bulletin day 2015.11.18 discloses an engine turbocharging air intake system, including the air filter air outlet steel pipe joint of connecting the booster air inlet side and connect in the intercooler air outlet steel pipe joint of the booster air exhaust side, still be equipped with the anti-surge pipeline, the anti-surge pipeline includes the anti-surge valve, the anti-surge valve is the three-way valve, the first passageway of anti-surge valve connect in the intercooler air outlet steel pipe joint, the second passageway of anti-surge valve connect in the air filter air outlet steel pipe joint, the third passageway of anti-surge valve connects in the air inlet jar of engine, the air current gets into the anti-surge valve and flows through respectively from the first passageway the air filter air outlet steel pipe joint, flows through the third passageway gets into the air inlet jar, by adopting the technical scheme, when the vehicle decelerates, the large pressure difference at the air inlet and exhaust sides of the supercharger can be discharged, the abrasion and fatigue of the supercharger are avoided, and the service life of the supercharger is prolonged. The patent prevents surging by introducing compressed gas between the compressor and the throttle valve into the compressor. The main disadvantage is the reduced efficiency of the turbocharger. The compressed gas is led out between the compressor and the throttle valve to avoid the surge of the turbocharger, but the energy of the compressed gas is not utilized.

Disclosure of Invention

The invention aims to provide a natural gas engine anti-surge system which can avoid the surge of a turbocharger, utilize the energy of compressed gas between a gas compressor and a throttle valve and play a role in all working conditions.

In order to achieve the aim, the natural gas engine anti-surge system designed by the invention 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.

Preferably, the first surge-preventing passage, and the portion passing through the ERG cooler are independent passages.

Preferably, 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.

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

In order to further suppress the wheezing, the method preferably further comprises the following steps: 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.

Preferably, the second surge-preventing passage and the portion passing through the intercooler are independent passage lines.

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

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

The invention has the beneficial effects that: the invention prevents surge in a mode of guiding out the compressed air between the air compressor and the air throttle, effectively utilizes the energy of the guided out compressed air, and improves the efficiency of the turbocharger; the invention can play a role in the full working condition range of the engine; the invention reduces exhaust manifold temperature while avoiding surge.

Drawings

Fig. 1 is a schematic structural view of the present invention, in which: the thick solid line with arrows indicates a high-temperature gas line, the thin solid line with arrows indicates a low-temperature gas line, the dotted line with arrows indicates an anti-surge line, and the arrows indicate the flow direction of the gas.

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

Detailed Description

The invention will now be described in further detail, including the preferred embodiments, by means of figure 1 and by way of a list of some alternative embodiments of the invention. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.

The exhaust gas of the natural gas engine is divided into two paths from an exhaust manifold 10, wherein one path flows into a turbine 5 to do work, and the other path is cooled by an EGR cooler 3 and then enters a mixer 9 through an EGR valve 7. Air enters the compressor 6 from the atmosphere through an air filter (not shown) to be pressurized, is cooled by the intercooler 4, passes through the throttle valve 8, and enters the mixer 9. Fresh air is mixed with recirculated exhaust gas in mixer 9 and enters the engine through an intake manifold (not shown). This part is prior art and will not be described in detail here. When the vehicle decelerates, the opening degree of the throttle valve 8 of the natural gas engine is reduced, 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 compressor 6 will be induced by 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.

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

the first and second conduits 11, 12 are both in communication with the ERG cooler 3 to form a first surge-preventing passage, and they are independent of the previous high-temperature gas passage flowing into the ERG cooler 3. That is, the ERG cooler 3 has two independent channels. The third line 13 and the fourth line 14 each communicate with the intercooler 3 to form a second surge-preventing passage, and they are independent of the passage of the pressurized air into the intercooler 4. That is, the intercooler 4 has two independent passages. The first surge preventing passage and the second surge preventing passage are also independent of each other.

When the opening degree of the throttle valve 8 of the natural gas engine is reduced, the first electromagnetic valve 1 and the second electromagnetic valve 2 are opened at the same time.

After the first electromagnetic valve 1 is opened, gas between the compressor 6 and the throttle valve 8 firstly passes through the first electromagnetic valve 1, then enters the EGR cooler 3 for heating, and finally enters the exhaust manifold 10 (the natural gas engine anti-surge system usually works in a low-speed large-load area with limited surge margin, and at the moment, 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 8 is led to the exhaust manifold 10, on the one hand, preventing compressor surge and, on the other hand, reducing the temperature of the exhaust manifold 10.

After the second electromagnetic valve 2 is opened, one path of 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 path of exhaust gas enters the inlet of the compressor 6 through the electromagnetic valve 2 after being cooled by the intercooler 4. The exhaust gas of the exhaust manifold 10 is guided to the inlet of the compressor 6, firstly, the pressure ratio of the gas at the outlet of the compressor 6 to the gas at the inlet is reduced, and surging is prevented; secondly, the exhaust pressure of the exhaust manifold 10 is reduced, so that the gas between the compressor 6 and the throttle valve 8 is guided to the exhaust manifold 10; finally, the exhaust energy of the exhaust manifold 10 is reduced, on the one hand, the supercharger power is reduced, and with the reduction of the supercharger power, the pressure ratio of the outlet gas to the inlet gas of the compressor 6 is also reduced, on the other hand, the temperature of the exhaust manifold 10 is reduced.

The purpose of the compressed gas between the compressor 6 and the throttle 8 is to avoid surge. The main purpose of 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 conveniently enter the exhaust manifold, and the secondary purpose is to reduce the pressure ratio of the compressor 6 by improving the inlet pressure of the compressor 6, inhibit surging and 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, which compensates for the energy loss caused by the exhaust gas being led out, and at the same time, reduces the exhaust manifold temperature.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and any modification, combination, replacement, or improvement made within the spirit and principle of the present invention is included in the scope of the present invention.