CN114251202A

CN114251202A - Engine EGR system and diagnosis method thereof

Info

Publication number: CN114251202A
Application number: CN202011017128.0A
Authority: CN
Inventors: 温聪; 孙华
Original assignee: Shenzhen Zhenyu New Energy Power Technology Co Ltd
Current assignee: Shenzhen Zhenyu New Energy Power Technology Co Ltd
Priority date: 2020-09-24
Filing date: 2020-09-24
Publication date: 2022-03-29

Abstract

The invention discloses an engine EGR system and a diagnosis method thereof, wherein the engine EGR system comprises: the EGR system comprises an EGR pipeline, a first temperature sensor, an intake manifold and a second temperature sensor. Be equipped with EGR cooler and EGR valve on the EGR pipeline, first temperature sensor connects on the EGR pipeline after the export of EGR valve to detect the exhaust gas temperature of EGR valve end of giving vent to anger, intake manifold connects the EGR pipeline, and second temperature sensor connects on intake manifold, with the temperature that detects intake manifold. According to the engine EGR system provided by the embodiment of the invention, whether the EGR pipeline is blocked can be directly judged according to the exhaust gas temperature of the exhaust end of the EGR valve detected by the first temperature sensor and the temperature of the intake manifold detected by the second temperature sensor, the detection is simple and easy to realize, and the detection cost is low.

Description

Engine EGR system and diagnosis method thereof

Technical Field

The invention belongs to the technical field of engine production and manufacturing, and particularly relates to an engine EGR system and a diagnosis method thereof.

Background

With increasingly stringent emission legislation requirements, EGR (exhaust gas recirculation) technology is increasingly being used on engines.

Exhaust Gas Recirculation (EGR) is a method for reducing the generation amount of nitrogen oxides and the pollution to the environment when Exhaust Gas is discharged by reducing the temperature and pressure of combustion by absorbing part of heat generated by combustion without introducing the Exhaust Gas after combustion into the combustion chamber of an engine to be mixed with fresh air.

In the process of introducing waste gas, an EGR pipeline plays a crucial role, whether the flow of the waste gas in the EGR pipeline is smooth or not directly influences the introduction amount of the waste gas, and the nitrogen oxide emission is overproof due to the fact that the flow of the waste gas introduced into an engine combustion chamber is too low or the waste gas cannot be introduced into the engine combustion chamber, so that the environmental pollution is caused. Therefore, how to accurately detect whether the EGR pipeline is blocked in real time is an important research topic in the field of engine EGR system research.

In the prior art, in order to accurately detect whether an EGR pipeline is blocked, namely whether waste gas is introduced into an engine combustion chamber or not, a flowmeter is usually added on the EGR pipeline to detect the flow of the waste gas in real time, and whether the EGR pipeline is blocked or not is judged, but the price of the flowmeter is expensive and the technical difficulty is high, so that the practicability of an engine EGR system cannot be improved.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the engine EGR system can rapidly judge whether the EGR pipeline is blocked, is simple to detect and low in cost, and solves the technical problems that the detection cost is high and the difficulty coefficient is high in the prior art.

The invention also aims to provide a diagnosis method of the engine EGR system.

An engine EGR system according to an embodiment of the invention includes: the EGR pipeline is provided with an EGR cooler and an EGR valve; the first temperature sensor is connected to the EGR pipeline behind the outlet of the EGR valve so as to detect the temperature of the exhaust gas at the gas outlet end of the EGR valve; the intake manifold is connected with the EGR pipeline; a second temperature sensor connected to the intake manifold to detect a temperature of the intake manifold.

According to the engine EGR system provided by the embodiment of the invention, the first temperature sensor is arranged for detecting the temperature of the exhaust gas at the gas outlet end of the EGR valve, and the second temperature sensor is arranged for detecting the temperature of the gas inlet manifold, when the EGR system works normally, the temperature of the exhaust gas discharged from the EGR pipeline is higher, and the temperature value measured by the first temperature sensor is larger than that measured by the second temperature sensor, so that the blockage condition of the EGR pipeline can be accurately judged by comparing the temperature values measured by the two temperature sensors, the detection is simple, the realization is easy, and the cost is lower. The engine EGR system of the application can reduce the emission of nitrogen oxides.

According to the engine EGR system of one embodiment of the invention, the engine EGR system further comprises a controller, the controller is respectively and electrically connected with the first temperature sensor and the second temperature sensor, the first temperature sensor transmits the measured exhaust gas temperature as a first temperature value to the controller, the second temperature sensor transmits the measured temperature of the intake manifold as a second temperature value to the controller, and the controller judges whether the EGR pipeline is blocked according to the difference value of the first temperature value and the second temperature value.

Optionally, when the difference between the first temperature value and the second temperature value is greater than or equal to a preset value, the controller determines that the EGR valve is normally opened and determines that the EGR pipeline is not blocked.

Optionally, the engine EGR system further includes an alarm, the alarm is electrically connected to the controller, when the difference between the first temperature value and the second temperature value is smaller than the preset value, the controller determines that the EGR pipeline is blocked, and the controller controls the alarm to give an alarm.

Optionally, the first temperature value and the second temperature value are equal when the EGR valve is closed.

Optionally, an introduction port is formed in the intake manifold to connect to an air outlet end of the EGR line, and the second temperature sensor is disposed on the intake manifold away from the introduction port.

Optionally, an installation boss is arranged on the EGR pipeline, the installation boss is close to the intake manifold, and the first temperature sensor is connected to the installation boss.

Optionally, engine EGR system still includes electron throttle valve, cylinder cap, exhaust manifold and three way catalyst converter, the electron throttle valve is connected intake manifold, the introduction port is established behind the electron throttle valve intake manifold is last, the one end of cylinder cap is connected intake manifold, the other end of cylinder cap is connected exhaust manifold, exhaust manifold's exhaust end is connected three way catalyst converter, three way catalyst converter with the inlet end intercommunication of EGR pipeline.

A diagnosis method of an engine EGR system according to an embodiment of the invention comprises the following steps: measuring the temperature difference delta T between the air outlet end of the EGR pipeline and the air inlet manifold in real time; comparing the temperature difference Delta T with a preset value Tc; when the delta T is larger than or equal to Tc, judging that the EGR valve is normally opened and the EGR pipeline is not blocked, and continuously measuring the temperature difference delta T between the air outlet end of the EGR pipeline and the air inlet manifold; when the temperature is 0 ℃ and T is less than Tc, judging that the EGR pipeline is blocked.

According to the diagnosis method of the engine EGR system, the first temperature sensor can measure the temperature of the air outlet end of the EGR pipeline in real time, the second temperature sensor can measure the temperature of the air inlet manifold in real time, the first temperature sensor and the second temperature sensor upload the measured temperature values to the controller, the controller receives the measured temperature and calculates the temperature difference between the air outlet end of the EGR pipeline and the air inlet manifold according to the measured temperature, and then the temperature difference value is compared with the preset value, so that whether the EGR pipeline is blocked or not can be judged quickly, the response speed is high, and the diagnosis is accurate.

Alternatively, when Δ T is 0 ℃, it is judged that the EGR valve is not opened; when the EGR pipeline is judged to be blocked, the controller outputs a fault signal or controls an alarm to give an alarm.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic diagram of an engine EGR system according to one embodiment of the present invention.

FIG. 2 is a schematic perspective view of a portion of an EGR circuit according to one embodiment of the present invention.

FIG. 3 is a flow chart of a diagnostic method for an engine EGR system in accordance with one embodiment of the present invention.

Reference numerals:

100. an engine EGR system;

1. an EGR line;

11. an EGR cooler; 12. an EGR valve; 13. mounting a boss;

2. a first temperature sensor;

3. an intake manifold;

31. an introduction port;

4. a second temperature sensor;

5. an electronic throttle valve;

6. a cylinder cover;

7. an exhaust manifold;

8. a three-way catalyst.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "inside", "outside", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

An engine EGR system 100 according to an embodiment of the present invention will be described with reference to the drawings.

An engine EGR system 100 according to an embodiment of the present invention, as shown in FIG. 1, includes: EGR line 1, first temperature sensor 2, intake manifold 3 and second temperature sensor 4.

As shown in fig. 1, an EGR cooler 11 and an EGR valve 12 are provided in the EGR line 1.

As shown in fig. 1, a first temperature sensor 2 is connected to the EGR line 1 after the outlet of the EGR valve 12 to detect the exhaust gas temperature at the outlet end of the EGR valve 12.

The intake manifold 3 is connected to the EGR line 1.

A second temperature sensor 4 is connected to the intake manifold 3 to detect the temperature of the intake manifold 3.

According to the structure, the engine EGR system 100 of the embodiment of the invention has the advantages that the EGR cooler 11 is arranged on the EGR pipeline 1, so that the temperature of the exhaust gas entering the EGR pipeline 1 can be reduced by the EGR cooler 11, the EGR pipeline 1 is prevented from being burnt due to overhigh temperature of the exhaust gas, and the service life of the EGR pipeline 1 is prolonged; and the temperature of the exhaust gas flowing from the EGR pipeline 1 into the intake manifold 3 is proper, so that the efficiency of mixed combustion in the combustion chamber is improved, and the generation amount of nitrogen oxides is reduced.

An EGR valve 12 is provided on the EGR line 1 for regulating the flow of exhaust gas into the intake manifold 3 to ensure that the flow of exhaust gas into the intake manifold 3 is within a preset range.

By arranging the first temperature sensor 2 on the EGR pipeline 1 after the outlet of the EGR valve 12, the first temperature sensor 2 can detect the temperature of the EGR pipeline 1 at the outlet end of the EGR valve 12 in real time. A second temperature sensor 4 is provided on the intake manifold 3 for detecting the temperature of the intake manifold 3 in real time. The user compares the temperature value that first temperature sensor 2 surveyed and the temperature value that second temperature sensor 4 surveyed, and when EGR system normally worked, the temperature of the exhaust gas of following the EGR pipeline was higher, and the temperature value that first temperature sensor 2 surveyed will be greater than the temperature value that second temperature sensor 4 surveyed, consequently through the size of the temperature value that compares two temperature sensors and survey, can judge whether EGR pipeline 1 blocks up, and response speed is fast and easy realization.

It can be understood that the engine EGR system 100 of the application has the advantages of simple structure, convenient arrangement, accurate and quick judgment of whether the EGR pipeline 1 is blocked or not through the matching use of the first temperature sensor 2 and the second temperature sensor 4, no need of setting a flow sensor and low cost.

Alternatively, the EGR cooler 11 is arranged on the EGR line 1 before the inlet of the EGR valve 12. Because of the too high exhaust gas temperature that gets into in the engine EGR system 100, can effectively reduce exhaust gas temperature through set up EGR cooler 11 before the import of EGR valve 12, make EGR valve 12 can not appear the phenomenon of scaling loss because of exhaust gas temperature is too high, and then prolong EGR valve 12's life-span.

Alternatively, the temperature sensors (the first temperature sensor 2 and the second temperature sensor 4) used in the engine EGR system 100 of the present invention may be contact temperature sensors, which have good detection stability and high accuracy, are not easily interfered by environmental factors, and can continuously detect the target for a long time.

In the description of the present invention, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features for distinguishing between the described features, whether they are sequential or not.

In some embodiments of the present invention, the engine EGR system 100 further comprises a controller (not shown in the figure), the controller is electrically connected to the first temperature sensor 2 and the second temperature sensor 4 respectively, the first temperature sensor 2 transmits the measured exhaust gas temperature as a first temperature value to the controller, the second temperature sensor 4 transmits the measured temperature of the intake manifold 3 as a second temperature value to the controller, and the controller determines whether the EGR pipe 1 is clogged according to a difference between the first temperature value and the second temperature value. That is to say, the controller is used for receiving the first temperature value that first temperature sensor 2 surveyed and the second temperature value that second temperature sensor 4 surveyed to calculate the difference between them according to first temperature value and the second temperature value received, and the controller can judge whether EGR pipeline 1 blocks up according to the difference of first temperature value and second temperature value.

Optionally, when the difference between the first temperature value and the second temperature value is greater than or equal to a preset value, the controller determines that the EGR valve 12 is normally opened and determines that the EGR pipeline 1 is not blocked. And then guarantee this application can judge through first temperature sensor 2 and second temperature sensor 4 whether EGR pipeline 1 blocks up.

Optionally, when the difference between the first temperature value and the second temperature value is smaller than the preset value, the controller determines that the EGR valve 12 is not normally opened or determines that the EGR pipeline 1 is blocked. At this time, the user can check whether the EGR valve 12 is normally opened by himself, if the EGR valve 12 is not opened, the EGR valve 12 can be opened by himself, the first temperature value and the second temperature value are re-detected, and the controller re-judges the difference value of the first temperature value and the second temperature value to judge whether the EGR pipeline 1 is blocked; if the EGR valve 12 is checked to be in a normal opening state, the EGR pipeline 1 is judged to be blocked.

Optionally, the preset value is a preset fixed value. The technician can set the preset value at his or her discretion based on the desired EGR rate to be achieved by the engine EGR system 100.

Optionally, the preset value is a positive number greater than zero. That is, in the case where the EGR valve 12 is normally opened and the EGR line 1 is not clogged, the exhaust gas temperature in the EGR line 1 is greater than the temperature of the intake manifold 3.

It should be noted that, in the present application, under the condition that the EGR valve 12 is normally opened and the EGR pipeline 1 is not blocked, the first temperature value is greater than the second temperature value. That is, the difference between the first temperature value and the second temperature value is calculated by subtracting the second temperature value from the first temperature value.

Optionally, the engine EGR system 100 further includes an alarm (not shown in the figure), the alarm is electrically connected to the controller, when the difference between the first temperature value and the second temperature value is smaller than the preset value, the controller determines that the EGR pipeline 1 is blocked, and the controller controls the alarm to alarm. The alarm is used for reminding the user to overhaul the EGR pipeline 1 in time, and ensures that the burnt waste gas can be introduced into the combustion chamber of the engine through the EGR pipeline 1 to be mixed with fresh air so as to reduce the generation amount of nitrogen oxides.

Optionally, the alarm may be one of a warning light, an alarm or a warning voice.

Optionally, the engine EGR system 100 further comprises a signal display terminal. The signal display end is electrically connected with the controller, when the controller judges that the EGR pipeline 1 is blocked, the controller can output a fault signal, and the fault signal is displayed on a user interface through the signal display end, so that a user can conveniently and visually and clearly distinguish that the EGR pipeline 1 is blocked.

Alternatively, the first and second temperature values are equal when the EGR valve 12 is closed. That is, when no exhaust gas flows in the EGR line 1 after the outlet of the EGR valve 12, the EGR line 1 and the intake manifold 3 are both close to the ambient temperature, so that the temperature at the outlet end of the EGR valve 12 is equal to the temperature of the intake manifold 3, and the difference between the temperatures is zero.

Alternatively, as shown in fig. 1, an intake port 31 is provided on the intake manifold 3 to connect to the outlet end of the EGR line 1, and a second temperature sensor 4 is provided on the intake manifold 3 away from the intake port 31. The exhaust gas in the EGR pipeline 1 can flow into the intake manifold 3 through the intake port 31, and the second temperature sensor 4 is far away from the intake port 31 because the temperature of the exhaust gas is far greater than the temperature of the intake manifold 3, so that the temperature of the intake manifold 3 detected by the second temperature sensor 4 is not affected by the temperature of the exhaust gas, and the temperature of the intake manifold 3 accurately detected by the second temperature sensor 4 is ensured.

Alternatively, as shown in fig. 2, the EGR pipe 1 is provided with a mounting boss 13, and the first temperature sensor 2 is connected to the mounting boss 13. The installation boss 13 provides the space of arranging for first temperature sensor 2, guarantees that first temperature sensor 2 stably sets up on EGR pipeline 1, improves the accuracy that first temperature sensor 2 detected.

Alternatively, the mounting boss 13 is provided near the intake manifold 3. That is, the first temperature sensor 2 is provided at the end of the EGR line 1 near the intake port 31 of the intake manifold 3, and the first temperature sensor 2 can detect the whole EGR line 1, thereby improving the accuracy of detection.

Alternatively, the EGR line 1 is made of a stainless steel material. The stainless steel material has good corrosion resistance and high temperature resistance, ensures that the waste gas with higher temperature cannot damage the EGR pipeline 1, and prolongs the service life of the EGR pipeline 1.

Optionally, a partial corrugated section is provided on the EGR line 1. The flexibility of the corrugated section multiplicable stainless steel EGR pipeline, the difficult fracture of stainless steel EGR pipeline.

Alternatively, as shown in fig. 1, the engine EGR system 100 further includes an electronic throttle valve 5, a cylinder head 6, an exhaust manifold 7, and a three-way catalyst 8.

As shown in fig. 1, the electronic throttle valve 5 is connected to the intake manifold 3. Fresh air can be introduced into the intake manifold 3 through the electronic throttle valve 5, and the intake amount of the fresh air is adjusted, effectively controlling the EGR rate.

Alternatively, as shown in fig. 1, the intake port 31 is provided on the intake manifold 3 behind the electronic throttle valve 5. The intake manifold 3 can be communicated with the EGR line 1 through the introduction port 31, ensuring smooth introduction of exhaust gas into the intake manifold 3.

Alternatively, as shown in fig. 1, one end of the cylinder head 6 is connected to the intake manifold 3. The intake manifold 3 is used for simultaneously introducing the exhaust gas of the EGR line 1 and the fresh air introduced by the electronic throttle valve 5 into the cylinder head 6, and mixing of the exhaust gas and the fresh air in the cylinder head 6 is realized to reduce the generation amount of nitrogen oxides.

Alternatively, as shown in fig. 1, the other end of the cylinder head 6 is connected to an exhaust manifold 7, and the exhaust end of the exhaust manifold 7 is connected to a three-way catalyst 8. The exhaust manifold 7 is arranged to introduce the burned harmful gases into the three-way catalyst 8, and the three-way catalyst 8 is used for converting the discharged harmful gases containing carbon monoxide, hydrocarbons, nitrogen oxides and the like into harmless carbon dioxide, water and nitrogen through oxidation and reduction, so that the pollution of the discharged harmful gases to the air is reduced.

Alternatively, as shown in fig. 1, the three-way catalyst 8 communicates with the intake end of the EGR line 1. Through setting up three way catalyst 8 at the inlet end of EGR pipeline 1, guarantee to get into the exhaust gas in the EGR pipeline 1 clean, and then ensure that the phenomenon of carbon deposit can not appear in EGR cooler 11 thereby to lead to EGR cooler 11 cooling performance to reduce.

The diagnostic method of the engine EGR system 100 according to the embodiment of the present invention, as shown in fig. 3, includes the steps of:

and step S1, measuring the temperature difference Delta T between the air outlet end of the EGR pipeline 1 and the air inlet manifold 3 in real time.

Step S2, comparing the temperature difference Δ T with a preset value Tc.

And step S3, when the delta T is larger than or equal to Tc, judging that the EGR valve 12 is normally opened and the EGR pipeline 1 is not blocked, and continuously measuring the temperature difference delta T between the air outlet end of the EGR pipeline 1 and the air inlet manifold 3.

And step S4, when 0℃ <. DELTA.T < Tc, judging that the EGR line 1 is clogged.

As can be seen from the above method, in the method for diagnosing the EGR system 100 of the engine according to the embodiment of the present invention, the first temperature sensor 2 detects the exhaust gas temperature at the outlet end of the EGR valve 12 in real time, the detected exhaust gas temperature is transmitted to the controller as the first temperature value, the second temperature sensor 4 detects the temperature of the intake manifold 3 in real time, the detected temperature of the intake manifold 3 is transmitted to the controller as the second temperature value, the controller receives the first temperature value and the second temperature value, and calculates the temperature difference Δ T between the outlet end of the EGR pipeline 1 and the intake manifold 3 according to the first temperature value and the second temperature value, after calculating the temperature difference Δ T, the controller compares the temperature difference Δ T with the preset value Tc, and when the controller determines that the temperature difference Δ T is greater than or equal to the preset value Tc, it is determined that the EGR valve 12 is normally opened and the EGR pipeline 1 is not blocked, that is, the engine EGR system 100 of the present application can send part of the exhaust gas generated by the engine back to the cylinder head 6 for combustion again, so as to meet the requirements of emission regulations; when the controller judges that the temperature is 0 ℃ and is less than Delta T and less than Tc, namely the first temperature value is lower and is greater than the second temperature value, the controller judges that the EGR pipeline 1 is blocked.

Alternatively, the controller outputs a fault signal when it is determined that the EGR line 1 is clogged. At the moment, the fault signal is displayed on a user interface through a signal display end, so that a user can conveniently and visually and clearly distinguish that the current EGR pipeline 1 is blocked, and the EGR pipeline 1 can be overhauled in time.

Alternatively, when the EGR pipeline 1 is judged to be blocked, the controller controls an alarm to give an alarm. The alarm is used for reminding the user in time to overhaul the EGR pipeline 1, and ensures that the burnt waste gas can be reintroduced into the combustion chamber of the engine through the EGR pipeline 1 to be mixed with fresh air so as to reduce the generation amount of nitrogen oxides.

Alternatively, when Δ T is 0 ℃, it is judged that the EGR valve 12 is not opened. That is, when the first temperature value is equal to the second temperature value, it indicates that the EGR valve 12 is not opened, and no exhaust gas flows into the exhaust end of the EGR valve 12, and at this time, the user may open the EGR valve 12 to ensure that part of the exhaust gas may be reintroduced into the combustion chamber of the engine through the EGR pipeline 1 to be mixed with fresh air.

Alternatively, when Δ T is 0 ℃, and the EGR valve 12 is in the open state. The EGR pipeline 1 is completely blocked, waste gas can not circulate in the EGR pipeline 1, and the controller controls the alarm to give an alarm to remind a user of timely overhauling the EGR pipeline 1.

Optionally, the EGR valve 12 is electrically connected to the controller. The controller may control the opening and closing of the EGR valve 12.

The specific structure of the engine EGR system 100 in accordance with the embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments of the present invention may be all embodiments obtained by combining the foregoing technical solutions, and are not limited to the following specific embodiments, which fall within the scope of the present invention.

Example 1

An engine EGR system 100, as shown in FIG. 1, comprising: EGR line 1, first temperature sensor 2, intake manifold 3 and second temperature sensor 4.

The intake manifold 3 is connected to the EGR line 1.

Example 2

An engine EGR system 100 is different from embodiment 1 in that, in embodiment 1, as shown in fig. 1, an intake manifold 3 is provided with an intake port 31 for connecting an outlet end of an EGR line 1, and a second temperature sensor 4 is provided on the intake manifold 3 apart from the intake port 31.

As shown in fig. 2, the EGR pipe 1 is provided with a mounting boss 13, the mounting boss 13 is provided near the intake manifold 3, and the first temperature sensor 2 is connected to the mounting boss 13.

Example 3

An engine EGR system 100 is different from embodiment 2 in that, in addition to embodiment 2, the engine EGR system 100 further includes a controller (not shown in the figure), the controller is electrically connected with a first temperature sensor 2 and a second temperature sensor 4 respectively, the first temperature sensor 2 transmits the measured exhaust gas temperature as a first temperature value to the controller, the second temperature sensor 4 transmits the measured temperature of an intake manifold 3 as a second temperature value to the controller, and the controller judges whether an EGR pipeline 1 is blocked according to the difference value between the first temperature value and the second temperature value.

The engine EGR system 100 further comprises an alarm, the alarm is electrically connected with the controller, when the difference value between the first temperature value and the second temperature value is smaller than a preset value and larger than 0 ℃, the controller judges that the EGR pipeline 1 is blocked, and the controller controls the alarm to give an alarm.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted" and "connected" are to be interpreted broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; either mechanically or electrically. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The specific structures and operating principles of other components of the engine EGR system 100 according to the embodiment of the present invention, such as the electronic throttle valve 5, the intake manifold 3, and the three-way catalyst 8, are known to those skilled in the art and will not be described in detail herein.

In the description herein, references to the description of the terms "embodiment," "example," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An engine EGR system, comprising:

the EGR pipeline is provided with an EGR cooler and an EGR valve;

the first temperature sensor is connected to the EGR pipeline behind the outlet of the EGR valve so as to detect the temperature of the exhaust gas at the gas outlet end of the EGR valve;

the intake manifold is connected with the EGR pipeline;

a second temperature sensor connected to the intake manifold to detect a temperature of the intake manifold.

2. The engine EGR system of claim 1 further comprising a controller electrically connected to said first and second temperature sensors, respectively, said first temperature sensor communicating a measured exhaust gas temperature as a first temperature value to said controller, said second temperature sensor communicating a measured intake manifold temperature as a second temperature value to said controller, said controller determining whether said EGR line is clogged based on a difference between said first and second temperature values.

3. The engine EGR system of claim 2, wherein when the difference between the first temperature value and the second temperature value is greater than or equal to a predetermined value, the controller determines that the EGR valve is normally open and determines that the EGR line is not blocked.

4. The engine EGR system of claim 3, further comprising an alarm electrically connected to the controller, wherein when the difference between the first temperature value and the second temperature value is less than the predetermined value, the controller determines that the EGR line is blocked, and the controller controls the alarm to alarm.

5. The engine EGR system of claim 2 wherein said first temperature value and said second temperature value are equal when said EGR valve is closed.

6. The engine EGR system of any of claims 1-5 wherein an intake port is provided in the intake manifold for connection to an outlet end of the EGR line, and the second temperature sensor is provided on the intake manifold remote from the intake port.

7. The engine EGR system of claim 6, wherein a mounting boss is provided on the EGR conduit, the mounting boss being disposed proximate to the intake manifold, the first temperature sensor being connected to the mounting boss.

8. The engine EGR system of claim 6 further comprising an electronic throttle valve, a cylinder head, an exhaust manifold and a three-way catalyst, wherein the electronic throttle valve is connected to the intake manifold, the intake port is provided on the intake manifold behind the electronic throttle valve, one end of the cylinder head is connected to the intake manifold, the other end of the cylinder head is connected to the exhaust manifold, the exhaust end of the exhaust manifold is connected to the three-way catalyst, and the three-way catalyst is communicated with the intake end of the EGR pipeline.

9. A method of diagnosing an EGR system of an engine, comprising the steps of:

measuring the temperature difference delta T between the air outlet end of the EGR pipeline and the air inlet manifold in real time;

comparing the temperature difference Delta T with a preset value Tc;

when the delta T is larger than or equal to Tc, judging that the EGR valve is normally opened and the EGR pipeline is not blocked, and continuously measuring the temperature difference delta T between the air outlet end of the EGR pipeline and the air inlet manifold;

when the temperature is 0 ℃ and T is less than Tc, judging that the EGR pipeline is blocked.

10. The diagnostic method for an EGR system of an engine according to claim 9, wherein it is judged that the EGR valve is not opened when Δ T ═ 0 ℃; when the EGR pipeline is judged to be blocked, the controller outputs a fault signal or controls an alarm to give an alarm.