Urea injection system and control method

Abstract

The invention belongs to the technical field of vehicles, and discloses a urea injection system and a control method thereof. The urea injection system comprises a gas storage tank, a urea tank, a pressurizing structure, a temperature control structure and a control unit, the gas storage tank is communicated with an inlet of the pressurizing structure, an outlet of the pressurizing structure is communicated with the urea tank, the pressurizing structure can pressurize gas output by the gas storage tank, and the temperature control structure is connected with the urea tank and used for heating the urea tank. According to the urea injection system, the working states of the temperature control structure and the pressurizing structure can be adjusted based on the temperature and the pressure of the urea tank, so that the temperature and the gas pressure in the urea tank are in a relatively proper range; therefore, the urea sprayed by the urea spraying system has proper temperature and pressure, the alarm of frequent pressure buildup failure of the urea tank can be avoided, and the exhaust performance of the vehicle is improved at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and particularly to a urea injection system and a control method thereof. Background Art

[0002] The main function of the SCR system (Selective Catalytic Reduction system) is to process nitrogen oxides (NOx) in the exhaust gas and reduce them to harmless nitrogen and water. The main function of the high-pressure gas-assisted urea injection system is to improve the atomization effect of the urea solution through high-pressure gas assistance for urea solution injection, thereby optimizing the performance of the SCR system (Selective Catalytic Reduction system). The urea tank is a container for storing urea. The urea tank is connected to the gas storage tank, and the high-pressure gas in the gas storage tank is used to drive the urea tank to inject urea. The high-pressure gas in the gas storage tank is also used for vehicle braking. Frequent vehicle braking will cause a large pressure fluctuation in the gas in the gas storage tank, resulting in insufficient pressure in the gas storage tank, which in turn affects the normal injection of urea, causes the urea tank to alarm, and affects the exhaust performance of the vehicle.

[0003] Therefore, a urea injection system and a control method are needed to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a urea injection system and a control method. The urea injection system is provided with a pressurizing structure, which can ensure that the air pressure in the urea tank always meets the pressure required for urea injection, thereby effectively avoiding normal pressure building in the urea tank, and improving the exhaust performance of the vehicle.

[0005] To achieve this purpose, the present invention adopts the following technical solutions:

[0006] A urea injection system, the urea injection system includes a gas storage tank, a urea tank, a pressurizing structure, a temperature control structure and a control unit. The outlet of the gas storage tank is connected to the inlet of the pressurizing structure, the outlet of the pressurizing structure is connected to the urea tank, the pressurizing structure can pressurize the gas output by the gas storage tank, the temperature control structure is connected to the urea tank and is used to heat the urea tank, and the control unit is electrically connected to the gas storage tank, the temperature control structure, the pressurizing structure and the urea tank. The control unit can obtain the pressure value and temperature value of the urea tank, and control the working state of the pressurizing structure based on the pressure value, and control the working state of the temperature control structure based on the temperature value.

[0007] As an optional technical solution, a gas pressure detector is provided on the urea tank, and the gas pressure detector is electrically connected to the control unit.

[0008] As an optional technical solution, a temperature detector is provided on the urea tank, and the temperature detector is electrically connected to the control unit.

[0009] As an alternative technical solution, the pressurizing structure is an air compressor, which includes a gas passage and a supercharger. The gas passage is used to pass gas, and the supercharger can pressurize the gas in the gas passage.

[0010] As an alternative technical solution, the temperature control structure includes a heating unit and a cooling unit, and both the heating unit and the cooling unit are electrically connected to the control unit.

[0011] As an alternative technical solution, the urea tank is further provided with an intake valve, which is communicated with the outlet of the pressurizing structure, and the intake valve is electrically connected to the control unit.

[0012] As an alternative technical solution, the urea injection system further includes a filtering unit, which is arranged between the gas storage tank and the pressurizing structure.

[0013] The present invention also adopts the following technical solutions:

[0014] A control method, which is used to control the urea injection system as described above. The control method includes:

[0015] S10. The control unit obtains the pressure value p of the urea tank and the temperature value t of the urea tank;

[0016] S20. Compare the temperature value t with a first temperature threshold T1 and a second temperature threshold T2 to determine whether T1 < t < T2. If so, enter S30; if not, the control unit controls the temperature control structure to start until T1 < t < T2 and then enter S30;

[0017] S30. The control unit compares the pressure value p with a first pressure threshold P1. If p ≥ P, enter S40; if p < P, enter S50;

[0018] S40. The control unit opens the gas passage of the air compressor and makes the supercharger in a shutdown state;

[0019] S50. The control unit opens the gas passage of the air compressor and makes the supercharger in a startup state.

[0020] As an alternative technical solution, the control unit controls the temperature control structure to start, and specifically enters S30 after T1 < t < T2 as follows: If t ≤ T1, the control unit controls the heating unit to start, and the heating unit heats the urea tank until T1 < t < T2 and then enters S30; if t ≥ T2, the control unit controls the cooling unit to start, and the cooling unit cools the urea tank until T1 < t < T2 and then enters S30.

[0021] As an alternative technical solution, S50 is specifically as follows: Compare the pressure value p with the second pressure threshold P2. If p ≥ P1, the control unit opens the gas passage of the air compressor and makes the supercharger in the first startup state; if p < P1, the control unit opens the gas passage of the air compressor and makes the supercharger in the second startup state.

[0022] Advantages of the present invention:

[0023] The present invention discloses a urea injection system, which includes a gas storage tank, a urea tank, a boosting structure, a temperature control structure and a control unit. The gas storage tank is connected to the inlet of the boosting structure, the outlet of the boosting structure is connected to the urea tank, the boosting structure can boost the gas output by the gas storage tank, the temperature control structure is connected to the urea tank and is used to heat the urea tank, and the control unit is electrically connected to the gas storage tank, the temperature control structure, the boosting structure and the urea tank. The control unit can obtain the pressure value and temperature value of the urea tank, and control the working state of the boosting structure based on the pressure value and control the working state of the temperature control structure based on the temperature value. This urea injection system can adjust the working states of the temperature control structure and the boosting structure based on the temperature and pressure of the urea tank, so that the temperature and gas pressure in the urea tank are both in a more appropriate range, and then the urea ejected by the urea injection system has appropriate temperature and pressure, which can not only avoid frequent pressure build-up failure alarms of the urea tank, but also improve the exhaust performance of the vehicle.

[0024] The present invention also discloses a control method applicable to the above urea injection system. The control method includes the control unit obtaining the pressure value p of the urea tank and the temperature value t of the urea tank; comparing the temperature value t with a temperature threshold to determine whether t > T. If so, it enters S30; if not, the control unit controls the temperature control structure to start until t > T and then enters S30; the control unit compares the pressure value p with a first pressure threshold P1. If p ≥ P, it enters S40; if p < P, it enters S50; the control unit opens the gas passage of the air compressor and makes the supercharger in a shutdown state; the control unit opens the gas passage of the air compressor and makes the supercharger in a startup state. This control method can control the supercharging structure and the temperature control structure based on the temperature and pressure of the urea tank, thereby always ensuring that the temperature and gas pressure in the urea tank meet the usage requirements, avoiding frequent alarms of pressure build-up failure in the urea tank, and improving the exhaust performance of the vehicle at the same time. Description of the Drawings

[0025] Figure 1 is the first structural schematic diagram of the urea injection system according to an embodiment of the present invention;

[0026] Figure 2 is the second structural schematic of the urea injection system according to an embodiment of the present invention;

[0027] Figure 3 is the flowchart of the control method according to an embodiment of the present invention;

[0028] Figure 4 is the logic diagram of the control method according to an embodiment of the present invention.

[0029] In the figure:

[0030] 10, gas storage tank;

[0031] 20, urea tank; 21, pressure gauge;

[0032] 30, supercharging structure;

[0033] 40, temperature control structure;

[0034] 50, control unit;

[0035] 60, filtering unit. Detailed Embodiments

[0036] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. In addition, it should be noted that for the sake of description, only parts related to the present invention are shown in the drawings, rather than all the structures.

[0037] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral body; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over", and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath", and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0039] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0040] Such as Figure 1 And Figure 2As shown in the figure, in this embodiment, a urea injection system is provided. The urea injection system includes a gas storage tank 10, a urea tank 20, a boosting structure 30, a temperature control structure 40, and a control unit 50. The gas storage tank 10 is communicated with the inlet of the boosting structure 30, and the outlet of the boosting structure 30 is communicated with the urea tank 20. The boosting structure 30 can boost the gas output from the gas storage tank 10. The temperature control structure 40 is connected to the urea tank 20 for heating the urea tank 20. The control unit 50 is electrically connected to the gas storage tank 10, the temperature control structure 40, the boosting structure 30, and the urea tank 20. The control unit 50 can obtain the pressure value and temperature value of the urea tank 20, and control the working state of the boosting structure 30 based on the pressure value, and control the working state of the temperature control structure 40 based on the temperature value. Specifically, in this embodiment, the control unit 50 can obtain the temperature value and pressure value of the urea tank 20, and can control the working of the temperature control structure 40 based on the temperature value of the urea tank 20, so that the temperature in the urea tank 20 is within a suitable temperature range. Then, based on the pressure value in the urea tank 20 under this temperature condition, the working state of the boosting structure 30 is adjusted, so that the temperature and gas pressure in the urea tank 20 are both within a relatively suitable range, so that the urea sprayed by the urea injection system has a suitable temperature and pressure, which can not only avoid frequent alarm of pressure building failure in the urea tank 20, but also improve the exhaust performance of the vehicle. This urea injection system is reasonably arranged. On the premise of the existing urea injection system, by setting the post-boosting structure 30, the frequent pressure building failure fault of the urea tank 20 can be avoided, so as to ensure the normal injection of urea and the normal driving of the vehicle.

[0041] Specifically, in this embodiment, the control unit 50 is an engine electronic control unit, that is, an ECU, which will not be elaborated here.

[0042] Further, as Figure 1 and Figure 2 shown, a gas pressure detector is provided on the urea tank 20, and the gas pressure detector is electrically connected to the control unit 50. Specifically, in this embodiment, the gas pressure detector provided on the urea tank 20 is a pressure gauge 21, and the pressure gauge 21 is electrically connected to the control unit 50. The control unit 50 can read the real-time gas pressure value of the pressure gauge 21, thereby improving the accuracy of the pressure control of the urea tank 20, avoiding control delay, and improving the service performance.

[0043] In another embodiment, the gas pressure detector can also be a gas pressure sensor, etc., which is not limited here.

[0044] Further, a temperature detector is provided on the urea tank 20, and the temperature detector is electrically connected to the control unit 50. Specifically, in this embodiment, the temperature detector provided on the urea tank 20 is a thermometer, and the thermometer is electrically connected to the control unit 50. The control unit 50 can read the real-time temperature value of the thermometer, and then feedback the temperature value in the urea tank 20 in real time. If the temperature is abnormal, it indicates that the control unit 50 is based on this temperature value, thereby avoiding control delay and improving the usage performance.

[0045] In another embodiment, the temperature detector can also be a temperature sensor, etc., which is not limited here.

[0046] Further, the supercharging structure 30 is an air compressor. The air compressor includes a gas passage and a supercharger. The gas passage is used to pass gas, and the supercharger can pressurize the gas in the gas passage. Specifically, in this embodiment, the gas passage of the air compressor is controlled by a solenoid valve, and the solenoid valve is electrically connected to the control unit 50. The control unit 50 can control the energization and de-energization of the solenoid valve, and then control the opening and closing of the solenoid valve, thereby controlling the opening and closing of the gas passage. When the solenoid valve is de-energized, the gas passage is disconnected, which can effectively prevent gas backflow, and then improve the stability of the system. The supercharger is also electrically connected to the control unit 50. When the control unit 50 controls the supercharger to work, the supercharger can increase the gas in the gas passage, thereby increasing the gas pressure in the urea tank 20.

[0047] Specifically, in this embodiment, the control unit 50 can also control the working power of the supercharger, and then control the exhaust volume of the supercharger.

[0048] Further, as Figure 1 and Figure 2 shown, the temperature control structure 40 includes a heating unit and a cooling unit, and both the heating unit and the cooling unit are electrically connected to the control unit 50. Specifically, in this embodiment, the heating unit is used to heat the urea tank 20, thereby increasing the temperature in the urea tank 20 and avoiding urea crystallization, which may lead to an increase in pressure due to volume expansion; while the cooling unit is used to cool the urea tank 20, thereby reducing the temperature in the urea tank 20 and avoiding urea decomposition caused by high temperature, which may affect the pressure in the urea tank 20 and also avoid high temperature from damaging the performance of urea, thereby ensuring the function of urea and the efficiency of the vehicle emission system.

[0049] Specifically, in this embodiment, the heating unit can be a heating pipe, etc., and the cooling unit can be a branch of the engine's cooling circulation system, which will not be elaborated here.

[0050] Further, the urea tank 20 is also provided with an intake valve which is connected to the outlet of the pressurizing structure 30 and electrically connected to the control unit 50. Specifically, in this embodiment, the intake valve of the urea tank 20 is preferably a one-way valve which is electrically connected to the control unit 50. When the urea tank 20 intakes air, the control unit 50 controls the one-way valve to open; when the urea tank 20 does not intake air, the control unit 50 controls the one-way valve to close, thereby avoiding the loss of gas in the urea tank 20 and ensuring the gas pressure in the urea tank 20.

[0051] Further, as Figure 1 and Figure 2 shown, the urea injection system further includes a filtering unit 60 which is arranged between the gas storage tank 10 and the pressurizing structure 30. Specifically, in this embodiment, the filtering unit 60 can filter the gas output from the gas storage tank 10, thereby avoiding the influence of impurities in the gas on the performance of the air compressor and prolonging its service life.

[0052] As Figure 3 and Figure 4 , this embodiment also discloses a control method which includes the following steps.

[0053] S10. The control unit 50 obtains the pressure value p of the urea tank 20 and the temperature value t of the urea tank 20.

[0054] Specifically, in this embodiment, the control unit 50 is electrically connected to the barometer 21 and the thermometer arranged on the urea tank 20, and the control unit 50 can obtain the air pressure value p and the temperature value t in the urea tank 20 in real time.

[0055] S20. Compare the temperature value t with the first temperature threshold T1 and the second temperature threshold T2 to determine whether T1 < t < T2. If so, enter S30; if not, the control unit 50 controls the temperature control structure 40 to start until T1 < t < T2 and then enter S30.

[0056] Specifically, in this embodiment, the first temperature threshold T1 is the lower limit of the temperature value in the urea tank 20, and the second temperature threshold T2 is the upper limit of the temperature value in the urea tank 20. By default, when the temperature value in the urea tank 20 is between the two, the working performance of urea will not be affected. If the temperature value t in the urea tank 20 is within this range, the air pressure value p in the urea tank 20 can be directly judged. If the temperature value t in the urea tank 20 is not within this range, the temperature in the urea tank 20 needs to be adjusted by the temperature control unit first to meet the temperature requirement, and then the air pressure value in the urea tank 20 is judged, thereby ensuring the effectiveness of urea injection.

[0057] Further, the control unit 50 controls the temperature control structure 40 to start until T1 < t < T2 and then enter S30 specifically means:

[0058] If t ≤ T1, the control unit 50 controls the heating unit to start, and the heating unit heats the urea tank 20 until T1 < t < T2 and then enters S30; if t ≥ T2, the control unit 50 controls the cooling unit to start, and the cooling unit cools the urea tank 20 until T1 < t < T2 and then enters S30.

[0059] Specifically, in this embodiment, such a setting enables the temperature in the urea tank 20 to be within the range that conforms to the urea performance, thereby ensuring better performance stability after urea injection, and further improving the exhaust performance of the vehicle.

[0060] S30. The control unit 50 compares the pressure value p with the first pressure threshold P1. If p ≥ P, it enters S40; if p < P, it enters S50.

[0061] Specifically, in this embodiment, the first pressure threshold P1 is the lower limit of the pressure required for urea injection. When the pressure in the urea tank 20 is higher than the first pressure threshold P1, direct urea injection can ensure its service performance, so there is no need for pressure supplementation, the urea tank 20 can inject urea normally, and there will be no alarm for pressure build-up failure, thereby reducing energy consumption; when the pressure in the urea tank 20 is lower than the first pressure threshold P1, at this time the pressure in the urea tank 20 is insufficient and pressure supplementation is required to inject urea normally.

[0062] S40. The control unit 50 opens the gas passage of the air compressor and makes the supercharger in a shutdown state.

[0063] Specifically, in this embodiment, when the pressure in the urea tank 20 is higher than the first pressure threshold P1, direct urea injection can ensure its service performance, so only the gas passage needs to be opened and the supercharger does not need to work.

[0064] S50. The control unit 50 opens the gas passage of the air compressor and makes the supercharger in a startup state.

[0065] Specifically, in this embodiment, when the pressure in the urea tank 20 is lower than the first pressure threshold P1, at this time the pressure in the urea tank 20 is insufficient and pressure supplementation is required to inject urea normally, so the gas passage needs to be opened and the supercharger needs to work to pressurize the gas in the gas passage to increase the gas pressure in the urea tank 20.

[0066] Further, S50 is specifically as follows: comparing the pressure value p with the second pressure threshold P2. If p ≥ P1, the control unit 50 opens the gas path of the air compressor and makes the supercharger in the first startup state; if p < P1, the control unit 50 opens the gas path of the air compressor and makes the supercharger in the second startup state.

[0067] Specifically, in this embodiment, the second pressure threshold P2 is lower than the first pressure threshold P1. When P2 ≤ p < P1, it indicates that the gas pressure in the urea tank 20 is slightly low at this time. It is not necessary to make the supercharger work at full power to make the air pressure value in the urea tank 20 meet the usage requirements, thereby reducing energy consumption; when p < P1, it indicates that the gas pressure in the urea tank 20 is very low at this time. It is necessary to make the supercharger work at full power to make the air pressure value in the urea tank 20 meet the usage requirements, thereby ensuring the injection pressure requirement of the urea tank 20.

[0068] Specifically, in this embodiment, the first temperature threshold T1, the second temperature threshold T2, the first pressure threshold P1, and the second pressure threshold P2 can all be specifically calibrated according to actual use, and are not limited herein.

[0069] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments, and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. Urea injection system, characterized in that: The urea injection system comprises a gas storage tank (10), a urea tank (20), a pressurizing structure (30), a temperature control structure (40) and a control unit (50); the outlet of the gas storage tank (10) is in communication with the inlet of the pressurizing structure (30); the outlet of the pressurizing structure (30) is in communication with the urea tank (20); the pressurizing structure (30) is capable of pressurizing the gas outputted from the gas storage tank (10); the temperature control structure (40) is connected to the urea tank (20) and is used to heat the urea tank (20); the control unit (50) is electrically connected to the gas storage tank (10), the temperature control structure (40), the pressurizing structure (30) and the urea tank (20); the control unit (50) is capable of acquiring a pressure value and a temperature value of the urea tank (20), and controlling a working state of the pressurizing structure (30) based on the pressure value, and controlling a working state of the temperature control structure (40) based on the temperature value.

2. The urea injection system according to claim 1, characterized in that: The urea tank (20) is provided with an air pressure detector, and the air pressure detector is electrically connected to the control unit (50).

3. The urea injection system according to claim 2, characterized in that: The urea tank (20) is provided with a temperature detector, and the temperature detector is electrically connected to the control unit (50).

4. The urea injection system according to claim 3, characterized in that: The pressurizing structure (30) is an air compressor, which comprises a gas passage and a supercharger. The gas passage is used for passing gas, and the supercharger can pressurize the gas in the gas passage.

5. The urea injection system according to claim 4, characterized in that: The temperature control structure (40) comprises a heating unit and a cooling unit, and both the heating unit and the cooling unit are electrically connected to the control unit (50).

6. The urea injection system according to any one of claims 1 to 5, characterized in that: The urea tank (20) is also provided with an air intake valve, the air intake valve is communicated with the outlet of the supercharging structure (30), and the air intake valve is electrically connected to the control unit (50).

7. The urea injection system according to claim 6, characterized in that: The urea injection system further comprises a filter unit (60), wherein the filter unit (60) is arranged between the gas storage tank (10) and the boost structure (30).

8. A control method, characterized in that: The control method is used to control the urea injection system according to claim 5, and the control method includes: S10, the control unit (50) obtains a pressure value p of the urea tank (20) and a temperature value t of the urea tank (20); S20, comparing the temperature value t with the first temperature threshold value T1 and the second temperature threshold value T2 to determine whether T1<t<T2, and if so, proceeding to S30; if not, the control unit (50) controls the temperature control structure (40) to start, and proceeding to S30 after T1<t<T2; S30, the control unit (50) compares the pressure value p with the first pressure threshold value P1, if p≥P, then enter S40, if p<P, then enter S50; S40, the control unit (50) opens the gas passage of the air compressor and puts the supercharger into a shutdown state; S50, the control unit (50) opens the gas passage of the air compressor and puts the supercharger into a startup state.

9. The control method according to claim 8, characterized in that: The control unit (50) controls the temperature control structure (40) to start, and enters S30 after T1<t<T2, which is specifically: If t≤T1, the control unit (50) controls the heating unit to start, and the heating unit heats the urea tank (20) until T1<t<T2, and then enters S30; if t≥T2, the control unit (50) controls the cooling unit to start, and the cooling unit cools the urea tank (20), and then enters S30.

10. The control method according to claim 8, characterized in that: The S50 is specifically: The pressure value p is compared with a second pressure threshold value P2; if p≥P1, the control unit (50) opens the gas passage of the air compressor and puts the supercharger in a first start-up state; if p<P1, the control unit (50) opens the gas passage of the air compressor and puts the supercharger in a second start-up state.

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