Urea supply injection system and control method thereof

Abstract

A urea supply and injection system includes a controller, a urea medium, a urea nozzle and a urea pump. The urea medium includes a first urea medium and a second urea medium. The first urea medium and the second urea medium have a first concentration and a second concentration and a first freezing point and a second freezing point, respectively, wherein the first freezing point is lower than the second freezing point. When the controller detects that the temperature of the second urea medium is higher than the second freezing point, the urea pump builds pressure and injects the second urea medium; when the controller detects that the temperature of the second urea medium is lower than or equal to the second freezing point, and detects that the temperature of the first urea medium is higher than the first freezing point, the urea pump builds pressure and injects the first urea medium. With such a configuration, it is possible to flexibly switch between the two urea media according to the temperature conditions, thereby improving the efficiency of the system and reducing power consumption. The present invention also relates to a control method for a urea supply and injection system.

Description

Technical Field

[0001] The invention relates to a urea supply injection system and a control method thereof, belonging to the technical field of engine exhaust post-treatment. Background Art

[0002] At present, in the post-treatment emission systems of marine engines, construction machinery and road machinery, SCR catalytic reducers usually use AUS32 or AUS40. Since the freezing point of AUS32 is -11℃, it is the most widely used. However, due to its higher urea concentration, AUS40 has an 8% longer cruising range than AUS32 at the same urea barrel level; but due to its freezing point of 0℃, it is most widely used in marine machinery, but cannot be widely used in inland ships or construction machinery or road vehicles at low temperatures. Summary of the invention

[0003] The object of the present invention is to provide an optimized urea supply injection system and a control method thereof.

[0004] To achieve the above object, the present invention adopts the following technical scheme: a urea supply and injection system, the urea supply and injection system comprising a controller, a urea medium, a urea nozzle and a urea pump for pumping the urea medium into the urea nozzle, the urea medium comprising a first urea medium and a second urea medium, the urea supply and injection system further comprising a first solenoid valve connected between the first urea medium and the urea pump and a second solenoid valve connected between the second urea medium and the urea pump, the first urea medium having a first concentration and a first freezing point, the second urea medium having a second concentration and a second freezing point, wherein the first concentration is less than the second concentration, and the first freezing point is lower than the second freezing point;

[0005] When the controller detects that the temperature of the second urea medium is higher than the second freezing point, the second solenoid valve is opened and the first solenoid valve is closed, and the controller controls the urea pump to build pressure and injects the second urea medium into the engine exhaust through the urea nozzle;

[0006] When the controller detects that the temperature of the second urea medium is lower than or equal to the second freezing point, and detects that the temperature of the first urea medium is higher than the first freezing point, the first solenoid valve is opened and the second solenoid valve is closed at the same time, and the controller controls the urea pump to build pressure and injects the first urea medium into the engine exhaust through the urea nozzle.

[0007] As a further improved technical solution of the present invention, the urea supply and injection system includes a first temperature sensor for detecting the temperature of the first urea medium, and the first temperature sensor is connected to the controller; the urea supply and injection system includes a second temperature sensor for detecting the temperature of the second urea medium, and the second temperature sensor is connected to the controller.

[0008] As a further improved technical solution of the present invention, the first urea medium is stored in a first urea cylinder, and the second urea medium is stored in a second urea cylinder.

[0009] As a further improved technical solution of the present invention, the urea supply injection system further includes an electric heating wire installed in the first urea cylinder and used for heating the first urea medium.

[0010] As a further improved technical solution of the present invention, when the controller detects that the temperature of the second urea medium is lower than or equal to the second freezing point, and detects that the temperature of the first urea medium is lower than or equal to the first freezing point, the controller starts the electric heating wire to heat the first urea medium;

[0011] When the controller detects that the temperature of the first urea medium is higher than the first freezing point, the first solenoid valve is opened and the second solenoid valve is closed. The controller controls the urea pump to build pressure and injects the first urea medium into the engine exhaust through the urea nozzle.

[0012] As a further improved technical solution of the present invention, the urea supply injection system further includes a third solenoid valve connected to the engine coolant, and when the engine coolant exceeds a certain temperature, the third solenoid valve is opened to heat the second urea medium with the engine coolant;

[0013] When the controller detects that the temperature of the second urea medium is higher than the second freezing point, the second solenoid valve is opened and the first solenoid valve is closed. The controller controls the urea pump to build pressure and injects the second urea medium into the engine exhaust through the urea nozzle.

[0014] As a further improved technical solution of the present invention, the first urea medium is AUS32, and the second urea medium is AUS40.

[0015] The present invention also relates to a control method of a urea supply and injection system, the urea supply and injection system comprising a controller, a urea medium, a urea nozzle, and a urea pump for pumping the urea medium into the urea nozzle, the urea medium comprising a first urea medium and a second urea medium, the urea supply and injection system further comprising a first solenoid valve connected between the first urea medium and the urea pump and a second solenoid valve connected between the second urea medium and the urea pump, the first urea medium having a first concentration and a first freezing point, the second urea medium having a second concentration and a second freezing point, wherein the first concentration is less than the second concentration, and the first freezing point is lower than the second freezing point;

[0016] The urea supply injection system further includes an electric heating wire for heating the first urea medium;

[0017] The urea supply injection system also includes a third solenoid valve connected to the engine coolant;

[0018] The control method of the urea supply injection system comprises the following steps:

[0019] S1: when the controller detects that the temperature of the second urea medium is higher than the second freezing point, the second solenoid valve is opened and the first solenoid valve is closed, the controller controls the urea pump to build pressure, and injects the second urea medium into the engine exhaust through the urea nozzle;

[0020] S2: when the controller detects that the temperature of the second urea medium is lower than or equal to the second freezing point, and detects that the temperature of the first urea medium is higher than the first freezing point, the first solenoid valve is opened and the second solenoid valve is closed, and the controller controls the urea pump to build pressure and injects the first urea medium into the engine exhaust through the urea nozzle;

[0021] S3: When the controller detects that the temperature of the second urea medium is lower than or equal to the second freezing point, and detects that the temperature of the first urea medium is lower than or equal to the first freezing point, the controller starts the electric heating wire to heat the first urea medium; when the controller detects that the temperature of the first urea medium is higher than the first freezing point, the first solenoid valve is opened and the second solenoid valve is closed at the same time, the controller controls the urea pump to build pressure, and injects the first urea medium into the engine exhaust through the urea nozzle;

[0022] S4: When the engine coolant exceeds a certain temperature, the third solenoid valve is opened, and the second urea medium is heated by the engine coolant; when the controller detects that the temperature of the second urea medium is higher than the second freezing point, the second solenoid valve is opened and the first solenoid valve is closed at the same time, and the controller controls the urea pump to build pressure and sprays the second urea medium into the engine exhaust through the urea nozzle.

[0023] As a further improved technical solution of the present invention, the first urea medium is AUS32, and the second urea medium is AUS40; the urea supply and injection system includes a first temperature sensor for detecting the temperature of the first urea medium, and the first temperature sensor is connected to the controller; the urea supply and injection system includes a second temperature sensor for detecting the temperature of the second urea medium, and the second temperature sensor is connected to the controller; the first urea medium is stored in a first urea cylinder, and the second urea medium is stored in a second urea cylinder.

[0024] As a further improved technical solution of the present invention, when the engine is stopped, the second solenoid valve is first opened and the first solenoid valve is closed at the same time, the urea pump is reversed, and the second urea medium in the pipeline is pumped back into the second urea cylinder. After a specified time is reached, the second solenoid valve is then closed and the first solenoid valve is opened at the same time, the urea pump is reversed, and the first urea medium is pumped back into the first urea cylinder.

[0025] Compared with the prior art, the present invention provides two different urea media and flexibly switches between the two urea media according to the temperature of the urea media, thereby improving the efficiency of the system and reducing power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the urea supply injection system of the present invention.

[0027] Figure 2 It is a schematic diagram of the control method of the urea supply injection system of the present invention. DETAILED DESCRIPTION

[0028] Please refer to Figure 1As shown, the present invention discloses a urea supply and injection system 100, which includes a controller 1, a urea medium, a urea nozzle 2, and a urea pump 3 for pumping the urea medium into the urea nozzle 2. The urea medium includes a first urea medium 41 and a second urea medium 42, and the urea supply and injection system 100 also includes a first solenoid valve 51 connected between the first urea medium 41 and the urea pump 3 and a second solenoid valve 52 connected between the second urea medium 42 and the urea pump 3. The first urea medium 41 has a first concentration and a first freezing point, and the second urea medium 42 has a second concentration and a second freezing point, wherein the first concentration is less than the second concentration, and the first freezing point is lower than the second freezing point. In the illustrated embodiment of the present invention, the first urea medium 41 is AUS32, and the second urea medium 42 is AUS40. The first freezing point is -11°C, and the second freezing point is 0°C.

[0029] In the illustrated embodiment of the present invention, the first urea medium 41 is stored in a first urea cylinder 61, and the second urea medium 42 is stored in a second urea cylinder 62. The urea supply and injection system 100 includes a first temperature sensor 611 for detecting the temperature of the first urea medium 41, and the first temperature sensor 611 is connected to the controller 1; the urea supply and injection system 100 includes a second temperature sensor 621 for detecting the temperature of the second urea medium 42, and the second temperature sensor 621 is connected to the controller 1.

[0030] The urea supply injection system 100 further includes an electric heating wire 612 installed in the first urea cylinder 61 and used to heat the first urea medium 41. Of course, in other embodiments, the electric heating wire 612 can be replaced by any other heating method.

[0031] The urea supply injection system 100 further includes a third solenoid valve 53 connected to the engine coolant. When the engine coolant exceeds a certain temperature (e.g., 85° C.), the third solenoid valve 53 is opened to heat the second urea medium 42 with the engine coolant.

[0032] Please refer to Figure 1 and Figure 2 As shown, the control method of the urea supply injection system 100 includes the following steps:

[0033] S1: When the controller 1 detects that the temperature of the second urea medium 42 is higher than the second freezing point, the second solenoid valve 52 is opened and the first solenoid valve 51 is closed. The controller 1 controls the urea pump 3 to build pressure and injects the second urea medium 42 into the engine exhaust gas through the urea nozzle 2. At this time, the controller controls the urea nozzle 2 to inject according to the relevant data of AUS40.

[0034] S2: When the controller 1 detects that the temperature of the second urea medium 42 is lower than or equal to the second freezing point, and detects that the temperature of the first urea medium 41 is higher than the first freezing point, the first solenoid valve 51 is opened, and the second solenoid valve 52 is closed at the same time, the controller 1 controls the urea pump 3 to build pressure, and injects the first urea medium 41 into the engine exhaust gas through the urea nozzle 2; at this time, the controller controls the urea nozzle 2 to inject according to the relevant data of AUS32.

[0035] S3: When the controller 1 detects that the temperature of the second urea medium 42 is lower than or equal to the second freezing point, and detects that the temperature of the first urea medium 41 is lower than or equal to the first freezing point, the controller 1 starts the electric heating wire 612 to heat the first urea medium 41; when the controller 1 detects that the temperature of the first urea medium 41 is higher than the first freezing point, the first solenoid valve 51 is opened, and the second solenoid valve 52 is closed at the same time, and the controller 1 controls the urea pump 3 to build pressure, and injects the first urea medium 41 into the engine exhaust through the urea nozzle 2; preferably, when the exhaust temperature reaches a certain value, the system starts to inject.

[0036] S4: When the engine coolant exceeds a certain temperature, the third solenoid valve 53 is opened, and the second urea medium 42 is heated and thawed by the engine coolant; when the controller 1 detects that the temperature of the second urea medium 42 is higher than the second freezing point, the second solenoid valve 52 is opened, and the first solenoid valve 51 is closed at the same time, and the controller 1 controls the urea pump 3 to build pressure, and injects the second urea medium into the engine exhaust through the urea nozzle 2.

[0037] Compared with the prior art, the present invention can use AUS40 in inland shipping or engineering machinery and road machinery under normal use conditions by adding a urea barrel and some devices, and optimizing strategies, and it is more energy-efficient. In addition, the present invention can effectively reduce the engine warm-up time, because AUS32 urea is less, and compared with AUS40, it only needs to be heated to above -10°C, that is, the required power consumption is significantly reduced. The present invention effectively utilizes the advantages of high concentration and high density of AUS40, which can increase the vehicle's cruising range and reduce the consumption of the vehicle's non-operating time. The present invention also effectively utilizes the heat of the engine to defrost AUS40 through the engine coolant and recover the energy. The present invention can be used in inland shipping or road and engineering machinery, and the two ureas can be flexibly switched according to the use environment.

[0038] After the system is finished working, the urea pump 3 is back-pumped and then the valve circuit is closed, which can reduce the volume of liquid in the pipeline caused by gravity and reduce the thawing power. Specifically, when the engine is stopped, it is necessary to minimize the residual amount of the first urea medium 41 and the second urea medium 42 in the entire urea supply system. First, the second solenoid valve 52 is opened, and the first solenoid valve 51 is closed at the same time. The urea pump 3 is reversed to back-pump the second urea medium 42 in the pipeline into the second urea cylinder 62. After reaching the specified time, the second solenoid valve 52 is closed, and the first solenoid valve 51 is opened at the same time. The urea pump 3 is reversed to back-pump the first urea medium 41 into the first urea cylinder 61. In this way, the power required for pipeline heating can be shortened and the risk of urea expansion caused by low temperature can be reduced.

[0039] In addition, the above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. The understanding of this specification should be based on the technical personnel in the relevant technical field. Although this specification has described the present invention in detail with reference to the above embodiments, ordinary technical personnel in the field should understand that the technical personnel in the relevant technical field can still modify or replace the present invention with equivalents, and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A urea supply and injection system, comprising a controller, a urea medium, a urea nozzle and a urea pump for pumping the urea medium into the urea nozzle, characterized in that: The urea medium includes a first urea medium and a second urea medium, and the urea supply injection system further includes a first solenoid valve connected between the first urea medium and the urea pump and a second solenoid valve connected between the second urea medium and the urea pump, the first urea medium has a first concentration and a first freezing point, the second urea medium has a second concentration and a second freezing point, wherein the first concentration is less than the second concentration, and the first freezing point is lower than the second freezing point; When the controller detects that the temperature of the second urea medium is higher than the second freezing point, the second solenoid valve is opened and the first solenoid valve is closed, and the controller controls the urea pump to build pressure and injects the second urea medium into the engine exhaust through the urea nozzle; When the controller detects that the temperature of the second urea medium is lower than or equal to the second freezing point, and detects that the temperature of the first urea medium is higher than the first freezing point, the first solenoid valve is opened and the second solenoid valve is closed at the same time, and the controller controls the urea pump to build pressure and injects the first urea medium into the engine exhaust through the urea nozzle.

2. The urea supply injection system according to claim 1, characterized in that: The urea supply and injection system includes a first temperature sensor for detecting the temperature of the first urea medium, and the first temperature sensor is connected to the controller; the urea supply and injection system includes a second temperature sensor for detecting the temperature of the second urea medium, and the second temperature sensor is connected to the controller.

3. The urea supply injection system according to claim 2, characterized in that: The first urea medium is stored in a first urea tank, and the second urea medium is stored in a second urea tank.

4. The urea supply injection system according to claim 3, characterized in that: The urea supply injection system further includes an electric heating wire installed in the first urea cylinder and used for heating the first urea medium.

5. The urea supply injection system according to claim 4, characterized in that: When the controller detects that the temperature of the second urea medium is lower than or equal to the second freezing point, and detects that the temperature of the first urea medium is lower than or equal to the first freezing point, the controller activates the electric heating wire to heat the first urea medium; When the controller detects that the temperature of the first urea medium is higher than the first freezing point, the first solenoid valve is opened and the second solenoid valve is closed. The controller controls the urea pump to build pressure and injects the first urea medium into the engine exhaust through the urea nozzle.

6. The urea supply injection system according to claim 5, characterized in that: The urea supply injection system further comprises a third solenoid valve connected to the engine coolant, and when the engine coolant exceeds a certain temperature, the third solenoid valve is opened to heat the second urea medium by using the engine coolant; When the controller detects that the temperature of the second urea medium is higher than the second freezing point, the second solenoid valve is opened and the first solenoid valve is closed. The controller controls the urea pump to build pressure and injects the second urea medium into the engine exhaust through the urea nozzle.

7. The urea supply injection system according to claim 1, characterized in that: The first urea medium is AUS32, and the second urea medium is AUS40.

8. A control method for a urea supply and injection system, the urea supply and injection system comprising a controller, a urea medium, a urea nozzle, and a urea pump for pumping the urea medium into the urea nozzle, the urea medium comprising a first urea medium and a second urea medium, the urea supply and injection system further comprising a first solenoid valve connected between the first urea medium and the urea pump, and a second solenoid valve connected between the second urea medium and the urea pump, the first urea medium having a first concentration and a first freezing point, the second urea medium having a second concentration and a second freezing point, wherein the first concentration is less than the second concentration, and the first freezing point is lower than the second freezing point; The urea supply injection system further includes an electric heating wire for heating the first urea medium; The urea supply injection system also includes a third solenoid valve connected to the engine coolant; The control method of the urea supply injection system comprises the following steps: S1: when the controller detects that the temperature of the second urea medium is higher than the second freezing point, the second solenoid valve is opened and the first solenoid valve is closed, the controller controls the urea pump to build pressure, and injects the second urea medium into the engine exhaust through the urea nozzle; S2: when the controller detects that the temperature of the second urea medium is lower than or equal to the second freezing point, and detects that the temperature of the first urea medium is higher than the first freezing point, the first solenoid valve is opened and the second solenoid valve is closed, and the controller controls the urea pump to build pressure and injects the first urea medium into the engine exhaust through the urea nozzle; S3: When the controller detects that the temperature of the second urea medium is lower than or equal to the second freezing point, and detects that the temperature of the first urea medium is lower than or equal to the first freezing point, the controller starts the electric heating wire to heat the first urea medium; when the controller detects that the temperature of the first urea medium is higher than the first freezing point, the first solenoid valve is opened and the second solenoid valve is closed at the same time, the controller controls the urea pump to build pressure, and injects the first urea medium into the engine exhaust through the urea nozzle; S4: When the engine coolant exceeds a certain temperature, the third solenoid valve is opened, and the second urea medium is heated by the engine coolant; when the controller detects that the temperature of the second urea medium is higher than the second freezing point, the second solenoid valve is opened and the first solenoid valve is closed at the same time, and the controller controls the urea pump to build pressure and sprays the second urea medium into the engine exhaust through the urea nozzle.

9. The control method of the urea supply injection system according to claim 8, characterized in that: The first urea medium is AUS32, and the second urea medium is AUS40; the urea supply and injection system includes a first temperature sensor for detecting the temperature of the first urea medium, and the first temperature sensor is connected to the controller; the urea supply and injection system includes a second temperature sensor for detecting the temperature of the second urea medium, and the second temperature sensor is connected to the controller; the first urea medium is stored in a first urea cylinder, and the second urea medium is stored in a second urea cylinder.

10. The control method of the urea supply injection system according to claim 9, characterized in that: When the engine is stopped, the second solenoid valve is first opened, and the first solenoid valve is closed at the same time, and the urea pump is reversed to draw the second urea medium in the pipeline back into the second urea cylinder. After a specified time is reached, the second solenoid valve is then closed, and the first solenoid valve is opened at the same time, and the urea pump is reversed to draw the first urea medium back into the first urea cylinder.

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