Low-pressure EGR air inlet system and automobile

Abstract

The invention discloses a low-pressure EGR air inlet system and an automobile, and relates to the technical field of EGR, the low-pressure EGR air inlet system comprises a first air inlet pipe, a second air inlet pipe, an air inlet intercooler, an exhaust pipe and a circulating pipe, an air outlet of the first air inlet pipe communicates with an air inlet of the second air inlet pipe, the air inlet intercooler is arranged on the second air inlet pipe, and an air outlet of the second air inlet pipe communicates with the circulating pipe; a throttle valve is connected between an air outlet of the second air inlet pipe and an air inlet of the air cylinder, an air inlet of the exhaust pipe communicates with an air outlet of the air cylinder, and the circulating pipe is connected with the first air inlet pipe and the air outlet pipe. A condenser is arranged on the first air inlet pipe, air entering the first air inlet pipe is condensed through the condenser, and the humidity of the air entering the first air inlet pipe is reduced; the water content of mixed gas is low, liquid water condensed by the air inlet intercooler is reduced, and therefore liquid water entering a combustion chamber of the air cylinder is reduced, and the problem that an engine is on fire is solved on the whole.

Description

Technical Field

[0001] The invention relates to the technical field of EGR, and in particular to a low-pressure EGR intake system and a car. Background Art

[0002] EGR (exhaust gas recirculation) technology was first applied to diesel engines. The EGR system includes high-pressure EGR and low-pressure EGR. When the EGR system is working, a part of the exhaust gas is sent into the combustion chamber through the intake system, thereby lowering the maximum combustion temperature and reducing nitrogen oxides.

[0003] A common low-pressure EGR system includes an intake pipe, an intake manifold, an outlet pipe, a cylinder and a circulation pipe. The intake pipe is connected to the intake manifold, and the cylinder is connected between the intake manifold and the outlet pipe. The intake pipe is used to supply air to the intake manifold, and the intake manifold is used to deliver gas into the cylinder. The exhaust gas discharged from the cylinder is discharged into the outlet pipe. A circulation pipe is connected between the outlet pipe and the intake pipe. The circulation pipe is used to deliver part of the exhaust gas in the exhaust pipe into the intake pipe. An intake intercooler is arranged on the intake pipe. The air and exhaust gas are mixed and enter the intake intercooler. The intake intercooler can cool the mixed gas entering the cylinder.

[0004] The water vapor content in the exhaust gas is relatively large, and the water vapor content in the mixed gas after the exhaust gas and air are mixed is relatively large. After the mixed gas enters the intake intercooler, the temperature of the mixed gas drops, causing the mixed gas to condense more liquid water. The liquid water is easy to enter the combustion chamber of the cylinder. After the liquid water enters the combustion chamber, it is easy to cause the engine to misfire. Summary of the invention

[0005] The main purpose of the present invention is to provide a low-pressure EGR intake system and a vehicle, aiming to improve the problem of engine misfire.

[0006] To achieve the above-mentioned object, the present invention provides a low-pressure EGR intake system, comprising a first intake pipe, a second intake pipe, an intake intercooler, a cylinder, an exhaust pipe and a circulation pipe, wherein an air outlet of the first intake pipe is connected to an air inlet of the second intake pipe, the intake intercooler is arranged on the second intake pipe, an air outlet of the second intake pipe is connected to an air inlet of the cylinder, an air inlet of the exhaust pipe is connected to an air outlet of the cylinder, an air outlet of the circulation pipe is connected to the first intake pipe, and an air inlet of the circulation pipe is connected to the exhaust pipe;

[0007] The first air inlet pipe is provided with a condenser, and the condenser is provided with a drainage member for unidirectionally discharging liquid water in the condenser. The air outlets of the condenser and the circulation pipe are sequentially arranged along the gas flow direction in the first air inlet pipe.

[0008] The technical solution of the present invention adopts a condenser to condense the air entering the first intake pipe, and the water in the air is condensed into liquid water. Then, the liquid water in the first intake pipe is discharged to the outside of the first intake pipe by means of a drainage member, so that the humidity of the air in the first intake pipe is reduced; the air after dehydration is mixed with the exhaust gas after contact to form a mixed gas, and the content of gaseous water in the air is reduced, that is, the humidity of the air is reduced. When the mixing ratio of air and exhaust gas remains unchanged, the content of water in the mixed gas can be reduced, that is, the humidity of the mixed gas is reduced; after the mixed gas enters the intake intercooler through the second intake pipe, the intake intercooler cools the mixed gas, and the water content of the mixed gas is low, so that the mixed gas is not easy to condense when it is cooled in the intake intercooler, thereby reducing the appearance of liquid water in the intake intercooler, thereby reducing the liquid water entering the combustion chamber of the cylinder, and improving the problem of engine misfire as a whole.

[0009] In one embodiment, the condenser includes a contraction section and a flare section, the contraction section is connected to the flare section, and the contraction section and the flare section are arranged in sequence along the air intake direction, and the opening size of the contraction section gradually decreases along the air intake direction.

[0010] In one embodiment, the condenser includes a connecting section, the connecting section is located between the contraction section and the expansion section, and two ends of the connecting section are respectively connected to the contraction section and the expansion section.

[0011] In one embodiment, a drainage hole is provided on the bottom side wall of the expanded section, and the drainage member is a drainage pipe, which is connected to the drainage hole.

[0012] In one embodiment, the inlet end of the drain pipe is higher than the outlet end of the drain pipe.

[0013] In one embodiment, the contraction section and the expansion section are provided in plurality in a one-to-one correspondence, and the contraction section and the corresponding expansion section constitute a group of changing sections, and the multiple groups of changing sections are connected in parallel.

[0014] In one embodiment, an air filter is connected to the air inlet of the first air inlet pipe.

[0015] In one embodiment, an air flow meter is provided on the air filter.

[0016] In one embodiment, a mixing valve for adjusting the amount of air is disposed on the first air intake pipe, the mixing valve is connected to the air outlet end of the condenser, and an EGR valve for adjusting the amount of exhaust gas is disposed on the circulation pipe.

[0017] The present invention also provides an automobile, comprising the low-pressure EGR intake system as claimed in any one of claims 1 to 9.

[0018] The technical solution of the present invention is to install the low-pressure EGR intake system on the automobile. During the operation of the automobile, the air entering the first intake pipe is condensed to remove water from the air in the first intake pipe. When the mixing ratio of air and exhaust gas remains unchanged, the water content in the mixed gas can be reduced. When the mixed gas is cooled in the intake intercooler, it is not easy to condense condensed water, thereby reducing the liquid water entering the combustion chamber of the cylinder, reducing the engine misfire caused by liquid water, and ensuring the stability of the automobile operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0020] Figure 1 A schematic structural diagram of an embodiment of a low-pressure EGR intake system provided by the present invention.

[0021] Description of Figure Numbers:

[0022] 1. First intake pipe; 11. Air filter; 12. Air flow meter; 13. Mixing valve; 14. Pressure relief valve; 2. Second intake pipe; 21. Throttle valve; 3. Intake intercooler; 4. Exhaust pipe; 41. Waste gas bypass valve; 42. Oxygen sensor; 43. Three-way catalytic converter; 5. Circulation pipe; 51. EGR valve; 52. EGR cooler; 53. Temperature sensor; 54. Pressure difference sensor; 541. Sub-sensor; 6. Cylinder; 7. Condenser; 71. Contraction section; 72. Expansion section; 73. Connection section; 8. Drainage piece; 9. Turbocharger; 91. Turbine end; 92. Compressor end.

[0023] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0026] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0027] EGR (Exhaust Gas Recirculation) technology was first applied to diesel engines. When the EGR intake system is working, part of the exhaust gas will be returned to the combustion chamber through the intake system, thereby reducing the maximum combustion temperature and reducing the formation of nitrogen oxides. The EGR intake system includes a low-pressure EGR intake system and a high-pressure EGR intake system. The low-pressure EGR system takes the exhaust gas from the turbine, and the exhaust gas is mixed with air to form a mixed gas. The temperature of the mixed gas drops when it enters the intercooler, thereby condensing liquid water. When the accelerator pedal changes suddenly, causing the intake pressure to change, a large amount of liquid water will enter the combustion chamber of the engine cylinder, causing the engine to misfire.

[0028] The present invention provides a low-pressure EGR intake system, aiming to improve the problem of engine misfire.

[0029] See also Figure 1In one embodiment of the present invention, the low-pressure EGR intake system includes a first intake pipe 1, a second intake pipe 2, an intake intercooler 3, an exhaust pipe 4, a circulation pipe 5 and a cylinder 6, wherein the cylinder 6 is a cylinder of the engine, an air outlet of the first intake pipe 1 is connected to an air inlet of the second intake pipe 2, the intake intercooler 3 is arranged on the second intake pipe 2, an air outlet of the second intake pipe 2 is connected to an air inlet of the cylinder 6 of the engine, an air inlet of the exhaust pipe 4 is connected to an air outlet of the cylinder 6 of the engine, an air outlet of the circulation pipe 5 is connected to the first intake pipe 1, and an air inlet of the circulation pipe 5 is connected to the exhaust pipe 4; a condenser 7 is arranged on the first intake pipe 1, and a drainage member 8 for unidirectionally discharging liquid water in the condenser 7 is arranged on the condenser 7, and the air outlet of the condenser 7 and the circulation pipe 5 are arranged in sequence along the gas flow direction in the first intake pipe 1.

[0030] The technical solution of the present invention adopts a condenser 7 to condense the air entering the first intake pipe 1, and the water in the air is condensed into liquid water. Then, the liquid water in the first intake pipe 1 is discharged to the outside of the first intake pipe 1 by means of a drainage member 8, so that the humidity of the air in the first intake pipe 1 is reduced; the air after dehydration is mixed with the exhaust gas after contact to form a mixed gas, and the content of gaseous water in the air is reduced, that is, the humidity of the air is reduced. When the mixing ratio of air and exhaust gas remains unchanged, the content of water in the mixed gas can be reduced, that is, the humidity of the mixed gas is reduced; after the mixed gas enters the intake intercooler 3 through the second intake pipe 2, the intake intercooler 3 cools the mixed gas, and the water content of the mixed gas is low, so that the mixed gas is not easy to condense when it is cooled in the intake intercooler 3, thereby reducing the appearance of liquid water in the intake intercooler 3, thereby reducing the liquid water entering the combustion chamber of the cylinder 6, and improving the problem of engine misfire as a whole.

[0031] The direction of the arrow in the first intake pipe 1 represents the flow direction of the air and the mixed gas in the first intake pipe 1; the direction of the arrow in the second intake pipe 2 represents the flow direction of the mixed gas in the second intake pipe 2, the direction of the arrow in the exhaust pipe 4 represents the flow direction of the exhaust gas in the exhaust pipe 4, and the direction of the arrow in the circulation pipe 5 represents the flow direction of the exhaust gas in the circulation pipe 5. The air in the first intake pipe and the mixed gas contact each other and mix to form a mixed gas, which then enters the second intake pipe 2, and then the mixed gas is sent to the cylinder 6, and the exhaust gas discharged from the cylinder 6 flows into the exhaust pipe 4, and the exhaust gas in the exhaust pipe 4 flows along the exhaust pipe 4, a part of the exhaust gas is discharged from the exhaust pipe 4 outlet, and the other part of the exhaust gas flows into the circulation pipe 5.

[0032] The condenser 7 may be a condenser tube disposed in the first air intake pipe 1 . Moisture in the air may condense on the condenser tube after contacting the condenser tube, thereby removing moisture from the air in the first air intake pipe 1 and reducing the humidity of the air in the first air intake pipe 1 .

[0033] See also Figure 1 The condenser 7 is preferably a venturi tube, which includes a contraction section 71 and an expansion section 72. The contraction section 71 is connected to the expansion section 72, and the contraction section 71 and the expansion section 72 are sequentially arranged along the air intake direction of the first air intake pipe 1. The opening size of the contraction section 71 gradually decreases along the air intake direction. When the air flows, it passes through the contraction section 71 and the expansion section 72 in sequence. When the air flows to the minimum cross section of the contraction section 71, the flow speed of the air increases, and the pressure of the air at the minimum cross section of the contraction section 71 decreases, so that the temperature of the air decreases, and the moisture in the air can be condensed into liquid water. The liquid water condensed by the air flows into the expansion section 72 driven by the air, thereby achieving the dehydration of the air in the first air intake pipe 1, thereby reducing the water content in the air in the first air intake pipe 1 and reducing the humidity of the air in the first air intake pipe 1.

[0034] The venturi tube also includes a connecting section 73, which is located between the contraction section 71 and the expansion section 72, and the two ends of the connecting section 73 are connected to the contraction section 71 and the expansion section 72 respectively. The cross section of the connecting section 73 is consistent with the minimum cross section size of the contraction section 71. The expansion section 72 and the contraction section 71 are connected by the connecting section 73. When the air flows in the connecting section 73, the time when the air is at a lower pressure is extended, that is, the air can be in a state of lower temperature for a longer time, and the time for condensing the air is increased, so that the moisture in the air is fully condensed into liquid water; it is convenient to attach the liquid water condensed from the air to the inner wall of the connecting section 73. When the air flows in the connecting section 73, the air can blow the liquid water on the inner wall of the connecting section 73 into the expansion section 72.

[0035] The cross section of the contraction section 71 along the direction perpendicular to the air flow is a circular ring, the connecting pipe is a circular tube, the opening size on the inner side of the expansion section 72 gradually increases along the air flow direction, and the cross section of the expansion section 72 along the direction perpendicular to the air flow can be a circular ring; after the air and liquid water flow into the expansion section 72, the liquid water can flow along the inner wall of the expansion section 72, reducing the purge of the air on the liquid water, and can gather the liquid water in the expansion section 72, which is convenient for the discharge of the liquid water.

[0036] See also Figure 1 A drainage hole is provided on the bottom side wall of the expanded section 72, and the drainage member 8 is a drainage pipe, which is connected to the drainage hole. The height of the bottom side wall of the expanded section 72 can be gradually reduced from the direction away from the drainage hole to the direction close to the drainage hole. The liquid water in the expanded section 72 can flow into the drainage hole under the driving force of gravity, and the water in the drainage hole can flow out of the expanded section 72 through the drainage pipe, so that the liquid water is discharged to the outside of the first air inlet pipe 1.

[0037] The inlet end of the drain port is connected to the flared section 72, and the inlet end of the drain pipe is higher than the outlet end of the drain pipe; preferably, the height of one end of the drain pipe connected to the flared section 72 is higher than other parts of the drain pipe, and the height of the other end of the drain pipe is higher than the lowest height of the drain pipe. The shape of the drain pipe is close to a U shape. After the liquid water in the flared section 72 flows into the drain pipe, the water can flow out from the lower end of the drain pipe, which can prevent the water in the drain pipe from flowing back into the flared section 72. There is a water column of a certain height in the drain pipe, which can seal the drain pipe and reduce the external air from entering the flared section 72 through the drain pipe.

[0038] When the air pressure at both ends of the drain pipe is balanced, the maximum height of the water column in the drain pipe is equal to the height difference between the height of a section of the drain pipe away from the expansion section 72 and the lowest height of the drain pipe, and the heights of the water column at both ends of the drain pipe are consistent.

[0039] A one-way valve may also be installed on the drain pipe. After the water in the expanded section 72 flows into the drain pipe, the one-way valve opens, and the water in the drain pipe can flow out of the drain pipe. When there is no liquid water in the drain pipe or the height of the liquid water in the drain pipe is low, the one-way valve is in a closed state, which can reduce the amount of external air passing through the one-way valve and entering the expanded section 72, thereby ensuring the cleanliness of the air in the expanded section 72.

[0040] See also Figure 1 The contraction section 71, the expansion section 72 and the connection section 73 are each provided with a plurality of corresponding contraction sections 71, the expansion section 72 and the connection section 73, and the corresponding contraction sections 71, the expansion section 72 and the connection section 73 constitute a set of change sections, and the change section is a venturi tube; the plurality of venturi tubes are arranged in parallel. The plurality of venturi tubes are connected in parallel, which can reduce the interception effect of the venturi tube on the air; thereby reducing the flow resistance and pressure drop of the intake of the first intake pipe 1, and improving the intake efficiency of the engine.

[0041] The air inlet of the first air inlet pipe 1 is connected to an air filter 11. With the help of the air filter 11, the air entering the first air inlet pipe 1 can be filtered, thereby ensuring the cleanliness of the air in the first air inlet pipe 1.

[0042] An air flow meter 12 is provided on the air filter 11 . By providing the air flow meter 12 , the flow rate of air entering the first intake pipe 1 can be detected, so as to facilitate real-time monitoring of the intake volume of the first intake pipe 1 .

[0043] The first air intake pipe 1 is provided with a mixing valve 13 for adjusting the amount of air, the condenser 7 and the mixing valve 13 are arranged in sequence along the flow direction of the air, and the circulation pipe 5 is provided with an EGR valve 51 for adjusting the amount of exhaust gas. By controlling the mixing valve 13, the amount of air flowing through the mixing valve 13 can be controlled, and by controlling the EGR valve 51, the amount of exhaust gas entering the first air intake pipe 1 can be controlled; when mixing air and exhaust gas, the proportion of the mixed gas can be controlled by controlling the amount of air and exhaust gas respectively.

[0044] See also Figure 1 A turbocharger 9 is arranged between the first intake pipe 1 and the exhaust pipe 4. The turbocharger 9 includes a turbine end 91 and a compressor end 92. The compressor end 92 is installed between the first intake pipe 1 and the second intake pipe 2, and the compressor end 92 is connected to the first intake pipe 1 and the second intake pipe 2; when the compressor end 92 is started, the mixed gas in the first intake pipe 1 can be pressurized and sent into the second intake pipe 2, thereby increasing the pressure of the gas in the second intake pipe 2, and realizing the pressurized air supply to the cylinder 6 of the engine. After the mixed gas is pressurized, the volume of the mixed gas is reduced, and the weight of the same volume of the mixed gas is increased, so that more mixed gas can be supplied to the cylinder 6 of the engine, ensuring the air supply effect to the cylinder 6 of the engine.

[0045] When the compressor end 92 is started, the mixed gas in the first air inlet pipe 1 will be pressurized and sent into the second air inlet pipe 2, which is easy to reduce the pressure of the air in the expansion section 72, reduce the dew point of the air in the expansion section 72, and condense the moisture in the expansion section 72, thereby improving the dehydration effect of the air in the expansion section 72. In addition, the water level of the water column in the drain pipe near the expansion section 72 rises, thereby ensuring that the pressure at both ends of the water column in the drain pipe remains balanced. The height difference between the two ends of the drain pipe can reduce the backflow of water into the expansion section 72 to a certain extent, and the water column can seal the drain pipe to reduce the entry of external air into the expansion section 72 from the drain pipe.

[0046] A throttle 21 is connected between the second intake pipe 2 and the cylinder 6 of the engine, and an intake manifold is connected between the throttle 21 and the cylinder 6. During the deceleration or parking process of the vehicle, the throttle 21 is correspondingly closed or reduced, in order to avoid damage to the throttle 21 and the pipeline when the gas pressure in the second intake pipe 2 is relatively high. A pressure relief valve 14 is connected between the second intake pipe 2 and the first intake pipe 1, and the air inlet of the pressure relief valve 14 is directly connected to the second intake pipe 2, and the air outlet of the pressure relief valve 14 is directly connected to the first intake pipe 1. When the throttle 21 is closed or reduced, the air pressure in the second intake pipe 2 increases. After the gas pressure in the second intake pipe 2 reaches a certain value, the pressure relief valve 14 opens and discharges part of the mixed gas in the second intake pipe 2 into the first intake pipe 1, and the air pressure in the second intake pipe 2 decreases. By releasing the gas in the second intake pipe 2 , the gas pressure in the second intake pipe 2 is reduced to reduce the damage to the throttle valve 21 , thereby reducing the damage to the throttle valve 21 caused by the gas pressure in the second intake pipe 2 .

[0047] The air outlet of the circulation pipe 5 is directly connected to the first air intake pipe 1 , and the air outlet of the circulation pipe 5 and the air outlet of the pressure relief valve 14 are arranged in sequence along the gas flow direction in the first air intake pipe 1 . When the pressure relief valve 14 exhausts air, the mixed gas discharged by the pressure relief valve 14 can be directly discharged into the mixed gas in the first air intake pipe 1 .

[0048] The air inlet of the pressure relief valve 14 is located between the intake intercooler 3 and the compressor end 92. Through the pressure relief valve 14, the pressure of the gas entering the intake intercooler 3 can be kept relatively stable. The intake intercooler 3 delivers the mixed gas with relatively stable pressure to the throttle 21, thereby keeping the pressure of the mixed gas in contact with the throttle 21 relatively stable.

[0049] The turbine end 91 is installed on the exhaust pipe 4. The turbine end 91 and the compressor end 92 are connected with a transmission shaft. When the exhaust gas flows in the exhaust pipe 4, the exhaust gas can start the turbine end 91. When the turbine end 91 is started, it can drive the compressor end 92 to operate.

[0050] See also Figure 1 The exhaust pipe 4 is also equipped with an exhaust bypass valve 41, which is connected in parallel with the turbine end 91. When the opening of the exhaust bypass valve 41 is increased, the amount of exhaust gas entering the turbine end 91 can be reduced; when the opening of the exhaust bypass valve 41 is reduced, the amount of exhaust gas entering the turbine end 91 can be increased. By controlling the opening of the exhaust bypass valve 41, the amount of exhaust gas entering the turbine end 91 can be controlled, and the power of the turbine end 91 can be controlled, and finally the power of the compressor end 92 can be controlled, thereby changing the boosting effect of the compressor end 92 on the mixed gas.

[0051] An oxygen sensor 42 is also installed on the exhaust pipe 4. The turbine end 91 and the exhaust bypass valve 41 are both located on one side of the oxygen sensor 42 close to the air inlet of the exhaust pipe 4. The exhaust gas contacts the oxygen sensor 42 after passing through the exhaust bypass valve 41 or the turbine end 91. With the help of the oxygen sensor 42, the oxygen content in the exhaust gas in the exhaust pipe 4 can be detected, thereby judging whether the engine is fully burned.

[0052] A three-way catalytic converter 43 is also provided on the exhaust pipe 4. The oxygen sensor 42 and the three-way catalytic converter 43 are arranged in sequence along the exhaust gas flow direction in the exhaust pipe 4. With the help of the three-way catalytic converter 43, carbon monoxide, hydrocarbons and nitrogen oxides in the exhaust gas can be catalyzed to reduce pollutants in the exhaust gas.

[0053] The air inlet of the circulation pipe 5 is located in the direction of the outlet of the three-way catalytic converter 43 close to the exhaust pipe 4, so that the exhaust gas treated by the three-way catalytic converter 43 can be sent into the circulation pipe 5, thereby reducing the carbon monoxide, hydrocarbons and nitrogen oxides entering the circulation pipe 5.

[0054] An EGR cooler 52 is also installed on the circulation pipe 5. The EGR cooler 52 and the EGR valve 51 are arranged in sequence along the exhaust gas flow direction on the circulation pipe 5. The temperature of the exhaust gas entering the circulation pipe 5 from the exhaust pipe 4 is about six hundred degrees Celsius. After the exhaust gas flows in the circulation pipe 5 and passes through the EGR cooler 52, the EGR cooler 52 can cool the exhaust gas to one hundred degrees Celsius, thereby lowering the temperature of the exhaust gas and reducing the damage to some rubber pipes caused by excessively high exhaust gas temperatures.

[0055] A temperature sensor 53 is installed on the circulation pipe 5. The temperature sensor 53 is located between the EGR valve 51 and the EGR cooler 52. The temperature sensor 53 can detect the temperature of the gas cooled by the EGR cooler 52, so as to facilitate the detection of the cooling effect of the EGR cooler 52 on the exhaust gas.

[0056] A pressure difference sensor 54 is also provided on the circulation pipe 5. The pressure difference sensor 54 includes two sub-sensors 541. The sub-sensor 541 is a pressure sensor. The EGR valve 51 is located between the two sub-sensors 541. One of the sub-sensors 541 is located between the EGR valve 51 and the EGR cooler 52. The two sub-sensors 541 detect the exhaust gas pressure at their respective points. Through the changes in the indications of the two sub-sensors 541, it is possible to detect whether there is leakage or blockage on the circulation pipe 5.

[0057] The present invention also proposes a car, which includes a low-pressure EGR intake system. The specific structure of the low-pressure EGR intake system refers to the above-mentioned embodiment. Since the car adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0058] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A low-pressure EGR intake system, characterized in that: The invention comprises a first air intake pipe, a second air intake pipe, an air intake intercooler, a cylinder, an exhaust pipe and a circulation pipe, wherein the air outlet of the first air intake pipe is connected to the air intake of the second air intake pipe, the air intake intercooler is arranged on the second air intake pipe, the air outlet of the second air intake pipe is connected to the air intake of the cylinder, the air intake of the exhaust pipe is connected to the air outlet of the cylinder, the air outlet of the circulation pipe is connected to the first air intake pipe, and the air intake of the circulation pipe is connected to the exhaust pipe; The first air inlet pipe is provided with a condenser, and the condenser is provided with a drainage member for unidirectionally discharging liquid water in the condenser. The air outlets of the condenser and the circulation pipe are sequentially arranged along the gas flow direction in the first air inlet pipe.

2. The low-pressure EGR intake system according to claim 1, characterized in that: The condenser comprises a contraction section and an expansion section, the contraction section is connected with the expansion section, and the contraction section and the expansion section are arranged in sequence along the air intake direction, and the opening size of the contraction section gradually decreases along the air intake direction.

3. The low-pressure EGR intake system according to claim 2, characterized in that: The condenser comprises a connecting section, wherein the connecting section is located between the contraction section and the expansion section, and two ends of the connecting section are respectively connected to the contraction section and the expansion section.

4. The low-pressure EGR intake system according to claim 2, characterized in that: A drainage hole is provided on the bottom side wall of the expanded section, and the drainage member is a drainage pipe, which is connected to the drainage hole.

5. The low-pressure EGR intake system according to claim 4, characterized in that: The inlet end of the drain pipe is higher than the outlet end of the drain pipe.

6. The low-pressure EGR intake system according to claim 2, characterized in that: The contraction sections and the expansion sections are provided in plurality in a one-to-one correspondence, and the contraction sections and the corresponding expansion sections constitute a group of change sections, and the plurality of groups of change sections are connected in parallel.

7. The low-pressure EGR intake system according to claim 1, characterized in that: The air inlet of the first air inlet pipe is connected with an air filter.

8. The low-pressure EGR intake system according to claim 7, characterized in that: An air flow meter is arranged on the air filter.

9. The low-pressure EGR intake system according to claim 1, characterized in that: The first air inlet pipe is provided with a mixing valve for adjusting the air volume, and the mixing valve is connected to the air outlet end of the condenser. The circulation pipe is provided with an EGR valve for adjusting the exhaust gas volume.

10. An automobile, characterized in that: Comprising the low-pressure EGR intake system as claimed in any one of claims 1 to 9.

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