Device for preventing urea crystallization of diesel engine, diesel engine starting system and vehicle

Abstract

The utility model provides a device for preventing urea crystallization of a diesel engine, a diesel engine starting system and a vehicle, relates to the field of diesel engine starting systems, and adopts the technical scheme that the device comprises an exhaust temperature sensor arranged at the air inlet end of a post-processing assembly, and further comprises a bypass air inlet pipe and a bypass air outlet pipe, the air inlet end of the bypass air inlet pipe is communicated with the air inlet end of the intercooler, and the air outlet end of the bypass air inlet pipe is communicated with an air inlet pipe of the diesel engine; a bypass valve is arranged on the bypass air inlet pipe or the bypass air inlet pipe is communicated with the air inlet end of the intercooler through a three-way mixed flow valve; the exhaust temperature sensor and the bypass valve are both electrically connected with a controller. The post-treatment assembly is simple in structure and high in reliability, and urea crystallization of the post-treatment assembly is effectively avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to diesel engine system field especially relates to a device of preventing diesel engine urea crystallization, diesel engine system and vehicle. BACKGROUND

[0002] The diesel engine aftertreatment assembly includes an SCR unit, the SCR unit is widely used in diesel engine to reduce nitrogen oxide emission, the tail gas enters the exhaust gas mixing pipe after coming out of the turbine, the mixing pipe is provided with a urea metering injection device, which is responsible for spraying urea water solution, the urea will hydrolyze and pyrolyze, generate NH3, then, using the catalyst in the SCR unit, the ammonia oxide is reduced to non-toxic and non-polluting nitrogen and water by NH3;But the problems are, on the one hand, when the diesel engine works under low load, the exhaust temperature is low, the urea hydrolysis pyrolysis efficiency is low, so that the urea water solution crystallizes on the inner wall of the exhaust pipe, a large amount of deposits are generated, on the other hand, the freezing point of urea is low, in cold working environment, crystallization is easy to occur.

[0003] In the related art, a diesel engine aftertreatment heating mixing device for preventing urea crystallization is disclosed, which comprises a resistance heating cylinder and an arc blade mixer, the resistance heating cylinder and the blade mixer are made into an integrated type, and are installed between the urea nozzle domain of the tail gas pipeline and the catalytic front section pipeline of the SCR catalyst, the resistance heating cylinder comprises an external circuit and a resistance wire, and comprises a control unit, a temperature sensor, a control switch, a power supply, a sliding resistor, a resistance wire net, an insulating support and an external switch; the temperature sensor is installed between the heating cylinder and the mixer, and is used for detecting the exhaust temperature, the control unit judges whether the heating mixing device should be started, if the temperature reaches the set low temperature, the control unit sends an instruction to turn on the control switch of the heating mixing device, and the heating mixing device starts heating; if the temperature reaches the set high temperature, the control unit sends an instruction to turn off the switch, and the heating mixing device stops heating.

[0004] By adopting the above technical scheme, the resistance heating cylinder needs to be additionally arranged, the structure of the resistance heating cylinder is relatively complex, and the components are relatively more, so that the failure rate of the heating mixing device is relatively high, the working reliability is relatively poor, the heating fails, and the vehicle provided with the diesel engine cannot work normally. UTILITY MODEL CONTENTS

[0005] In order to solve the technical problem that the diesel engine aftertreatment assembly is easy to produce urea crystallization in the prior art, the utility model provides a device of preventing diesel engine urea crystallization, a diesel engine system and a vehicle, which are simple in structure, high in reliability, and can effectively avoid urea crystallization of the aftertreatment assembly.

[0006] The utility model discloses a device for preventing urea crystallization of diesel engine, which comprises an exhaust temperature sensor, the exhaust temperature sensor is arranged at the air inlet end of the aftertreatment assembly, and further comprises:

[0007] A bypass air inlet pipe is arranged, the air inlet end of the bypass air inlet pipe is communicated with the air inlet end of the intercooler, and the air outlet end of the bypass air inlet pipe is communicated with the diesel engine air inlet pipe.

[0008] A bypass valve is arranged on the bypass air inlet pipe and communicated with the air inlet end of the intercooler, or the bypass air inlet pipe is communicated with the air inlet end of the intercooler through a three-way mixing valve.

[0009] The exhaust temperature sensor and the bypass valve are electrically connected with the controller.

[0010] The bypass air inlet pipe is arranged, so that fresh air can directly enter the diesel engine without passing through the intercooler, the exhaust temperature of the diesel engine is increased, the temperature of the exhaust gas entering the aftertreatment assembly is increased, and urea crystallization is effectively inhibited.

[0011] Further, a one-way valve is arranged on the bypass air inlet pipe and located at the front end of the bypass valve in the gas flow direction, and the one-way valve is directed to the diesel engine air inlet pipe.

[0012] The one-way valve can prevent gas backflow.

[0013] Further, a throttle valve is arranged at the air outlet end of the intercooler and the diesel engine air inlet pipe, and the throttle valve is electrically connected with the controller.

[0014] The throttle valve can cooperate with the bypass valve to control the proportion of the fresh air directly entering the diesel engine and the fresh air entering the diesel engine through the intercooler, so that the dual requirements of fuel economy and prevention of urea crystallization are met.

[0015] Further, a flow sensor is arranged at the air outlet end of the intercooler and located at the front part of the throttle valve in the gas flow direction.

[0016] Further, a three-way mixing valve is arranged on the bypass air inlet pipe, a Venturi ejector device is communicated with the air outlet end of the bypass air inlet pipe and the air outlet end of the intercooler in the gas flow direction.

[0017] The three-way mixing valve and the Venturi ejector device are arranged, so that the number of valves is reduced, and the structure is further simplified.

[0018] Further, an electric switch is arranged, the electric switch is electrically connected with the fan assembly of the diesel engine, and the electric switch is electrically connected with the controller.

[0019] The utility model discloses a set up the on-off of electric switch control fan assembly, can close diesel engine fan when low temperature starting, promote the temperature of diesel engine low temperature starting.

[0020] Secondly, the utility model also provides a diesel engine starting system, including turbocharger, intercooler, diesel engine and aftertreatment assembly, also includes the device of preventing diesel engine urea crystallization of above-mentioned.

[0021] Further, the bypass intake pipe is integrated with the intercooler.

[0022] The utility model discloses a set up the integration of bypass intake pipe and intercooler, reduce the installation space of more occupancy of bypass intake pipe, facilitate assembly.

[0023] Thirdly, the utility model also provides a vehicle, including the diesel engine starting system of above-mentioned.

[0024] From the above technical scheme, the utility model has the following advantages:

[0025] The utility model discloses a device of preventing diesel engine urea crystallization, diesel engine starting system and vehicle, through setting up bypass intake pipe, can control fresh air not through intercooler directly into diesel engine, promote diesel engine exhaust temperature, increase the exhaust gas temperature of entering aftertreatment assembly, better inhibit urea crystallization, through setting up check valve, can prevent gas backflow, through setting up throttle valve, can cooperate with bypass valve, control the proportion of directly entering diesel engine and entering diesel engine through intercooler, satisfy the dual needs of fuel economy and prevent urea crystallization, through setting up the on-off of electric switch control fan assembly, can close diesel engine fan when low temperature starting, promote the temperature of diesel engine low temperature starting. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical scheme of the utility model, the following will be to the drawing needed to be used in the description of simple introduction, obviously, the drawing in the following description only some embodiments of the utility model, for those skilled in the art, under the premise of not paying creative labor, can also obtain other drawings according to these drawings.

[0027] Figure 1 It is the structure principle drawing of the embodiment one of the utility model.

[0028] Figure 2 It is the structure principle drawing of the embodiment two of the utility model.

[0029] In the figure, 1. turbocharger; 2. bypass valve; 3. bypass intake pipe; 4. non-return valve; 5. throttle valve; 6. intercooler; 7. fan assembly; 8. diesel engine intake pipe; 9. diesel engine; 10. exhaust pipe; 12. after-treatment assembly; 13. venturi ejector; 14. coolant temperature sensor; 15. exhaust temperature sensor; 16. intercooler rear intake air temperature sensor; 17. three-way mixing valve; 18. coolant radiator; 19. intercooler pipeline. DETAILED DESCRIPTION

[0030] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the specific embodiments. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of them. Based on the embodiments in this patent, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this patent. Specific implementation method 1

[0032] like Figure 1 As shown, this specific embodiment provides a device for preventing urea crystallization in a diesel engine, including an exhaust temperature sensor 15, a bypass intake pipe 3, and a bypass valve 2. The exhaust temperature sensor 15 is arranged at the intake end 10 of the after-treatment assembly 12, the bypass intake pipe 3, and the outlet end of the bypass intake pipe 3 is connected to the diesel engine intake pipe 8; the intake end of the bypass intake pipe 3 is provided with a bypass valve 2 and is connected to the intake end of the intercooler 6; the exhaust temperature sensor 15 and the bypass valve 2 are both electrically connected to the controller.

[0033] This specific embodiment sets a bypass intake pipe 3. When the exhaust temperature is lower than the set threshold, it can control part of the fresh air to directly enter the diesel engine 9 without cooling through the intercooler 6, thereby increasing the exhaust temperature of the diesel engine 9 and the exhaust gas temperature entering the after-treatment assembly, thereby effectively inhibiting urea crystallization. Compared with the existing technology, the combustion temperature of the diesel engine 9 is directly utilized without adding an additional heating device, and the structure is relatively simple, the failure rate is low, and the reliability is high. At the same time, it can also increase the intake temperature and improve the starting performance of the diesel engine. On the one hand, low-temperature and ultra-low-temperature cold starts are achieved, and on the other hand, rapid starting of the diesel engine 9 is achieved.

[0034] like Figure 1 As shown, in order to prevent gas backflow, in this specific embodiment, a one-way valve 4 is provided on the bypass intake pipe 3 and at the front end of the bypass valve 2 along the gas flow direction, and the one-way valve 4 is connected to the diesel engine intake pipe 8.

[0035] like Figure 1As shown, further comprising a throttle valve 5 and a flow sensor, the throttle valve 5 is arranged on the intercooler pipeline 19 between the outlet end of the intercooler 6 and the diesel engine intake pipe 8, the throttle valve 5 is electrically connected with the controller, and the flow sensor is arranged at the outlet end of the intercooler 6 and located in front of the throttle valve 5 in the gas flow direction; By arranging the throttle valve, the proportion of the gas directly entering the diesel engine 9 and the gas entering the diesel engine 9 through the intercooler 6 can be controlled in cooperation with the bypass valve 2, so as to meet the dual requirements of fuel economy and prevention of urea crystallization.

[0036] In the specific embodiment, an electric switch is further included, which is electrically connected with the fan assembly 7 of the diesel engine 9 and is electrically connected with the controller, and the fan assembly 7 is used for cooling the liquid radiator 18; when the diesel engine 9 is started at low temperature, the fan assembly 7 is closed, which is beneficial to quickly improve the problem of the diesel engine 9 and realize quick start, and after normal start, the fan assembly 7 is opened for heat dissipation.

[0037] The specific embodiment further includes an ambient temperature sensor for sensing the ambient temperature, so that the diesel engine 9 is started according to the set degree.

[0038] The working process of the device for preventing urea crystallization of the diesel engine is as follows:

[0039] When the diesel engine 9 is started at low temperature, the intake temperature of the diesel engine 9 is low, the bypass valve 2 is opened, and the intake temperature of the diesel engine 9 is increased by adjusting the opening degree of the bypass valve 2, and at the same time, the fan assembly 7 is closed and the fan does not rotate; After successful start, the bypass valve 2 can be closed and the electric switch of the fan assembly 7 is opened.

[0040] Under the condition that the exhaust temperature of the diesel engine 9 is low, the opening degree of the bypass valve 2 can be controlled to let part of the intake gas not pass through the intercooler 6 and directly enter the diesel engine intake pipe to increase the exhaust temperature of the diesel engine and improve the urea crystallization; When the urea is actively regenerated, the opening degrees of the bypass valve 2 and the throttle valve 5 can be controlled to increase the exhaust temperature of the diesel engine, shorten the active regeneration time, and reduce the active regeneration fuel consumption. Specific embodiment two

[0042] As Figure 2As shown, this specific embodiment provides a device for preventing urea crystallization in a diesel engine, including an exhaust temperature sensor 15, a bypass intake pipe 3, and a three-way mixing valve 17. The exhaust temperature sensor 15 is disposed at the intake end 10 of the aftertreatment assembly 12, and the three-way mixing valve 17 is disposed between the outlet end of the turbocharger 1 and the inlet end of the intercooler 6. The inlet end of the bypass intake pipe 3 is connected to the inlet end of the intercooler 6 via the three-way mixing valve 17, and the outlet end of the bypass intake pipe 3 is connected to the diesel engine intake pipe 8. The exhaust temperature sensor 15 and the three-way mixing valve 17 are both electrically connected to a controller. The three-way mixing valve 17 is driven by a motor. In an initial state, i.e., a reset state, the bypass intake pipe 3 is closed and the intercooler pipe 19 (the pipe connecting the outlet end of the intercooler and the diesel engine intake pipe) is fully open. When the diesel engine 9 is powered on, the opening of the three-way mixing valve 17 is controlled according to the ECU algorithm. The valve is reset when the diesel engine 9 is shut down or powered off.

[0043] like Figure 2 As shown, in order to prevent gas backflow, in this specific embodiment, along the gas flow direction, the rear part of the diesel engine intake pipe 8 is connected with a Venturi ejector 13. Specifically, the air outlet end of the Venturi ejector 13 is connected to the diesel engine intake pipe 8, and the ejection port of the Venturi ejector 13 is connected to the bypass intake pipe 3. The main line of the Venturi ejector 13 is connected to the intercooler line 19. When the intercooled air passes through the Venturi ejector 13, the pressure at the ejection port is reduced, and the air in the bypass intake pipe 3 is ejected into the main line, so as to avoid the backflow of air in the bypass intake pipe 3 when the bypass intake pipe and the intercooler line 19 are both opened. In this specific embodiment, by arranging the three-way mixing valve 17 and the Venturi ejector 13, the valve setting can be reduced and the structure can be further simplified.

[0044] In this specific embodiment, an electric switch is also included, which is electrically connected to the fan assembly 7 of the diesel engine 9, and the electric switch is electrically connected to the controller; when the diesel engine 9 is started at a low temperature, the fan assembly 7 is turned off to reduce heat loss, which is conducive to quickly improving the diesel engine 9 and achieving rapid startup. After normal startup, the fan assembly 7 is turned on again to dissipate heat.

[0045] In this specific embodiment, it also includes an intercooler after-intake air temperature sensor 16 and a coolant temperature sensor 14. The intercooler after-intake air temperature sensor 16 is arranged at the intake end of the diesel engine 9, and the coolant temperature sensor 14 is arranged on the return water pipeline of the cooling system of the diesel engine 9. The return water pipeline is connected to the coolant radiator 18 of the cooling system.

[0046] The embodiment can improve the starting performance. When the diesel engine 9 starts and the diesel engine 9 rotates at a speed lower than the idle speed, and the temperature of the post-intercooling intake air is low, the three-way mixing valve 17 is opened, the bypass intake pipe 3 is fully opened, and the intercooling pipe 19 is fully closed. The fan assembly 7 does not rotate. Because the pressure loss of the bypass intake pipe 3 is lower than the pressure loss of the intercooler 6, the starting time of the diesel engine 9 is shortened.

[0047] The embodiment can improve the low-temperature cold starting performance. When the ambient temperature is low, the three-way mixing valve 17 is opened, the bypass intake pipe 3 is fully opened, and the intercooling pipe 19 is fully closed. The temperature of the air participating in combustion at low temperature is increased, and the low-temperature cold starting performance is optimized. After the starting is completed, the three-way mixing valve 17 is kept in the state of the bypass intake pipe 3 being fully opened and the intercooling pipe 19 being fully closed until the temperature of the post-intercooling intake air reaches the set temperature. Then, the three-way mixing valve 17 gradually returns to the initial opening state, the bypass intake pipe 3 is closed, and the intercooling pipe 19 is fully opened.

[0048] The embodiment can quickly increase the temperature of the diesel engine. After the diesel engine 9 starts, when the temperature of the diesel engine coolant is low, the three-way mixing valve 17 is kept in the state of the bypass intake pipe 3 being fully opened and the intercooling pipe 19 being fully closed. The temperature of the intake air is increased, the combustion temperature is increased, and the temperature of the diesel engine coolant is increased to the set temperature. Then, the three-way mixing valve 17 gradually returns to the initial opening state, the bypass intake pipe 3 is closed, and the intercooling pipe 19 is fully opened.

[0049] The embodiment can also increase the exhaust temperature when the diesel engine 9 continuously operates in a low-temperature environment, improve the passive regeneration efficiency, and avoid frequent activation of the thermal management program. During the operation of the diesel engine 9, when the speed of the diesel engine 9 is higher than the idle speed and the temperature of the post-intercooling intake air is low, the three-way mixing valve 17 is opened, the bypass intake pipe 3 and the intercooling pipe 19 are both opened, the opening degree is adjusted according to the temperature difference between the temperature of the post-intercooling intake air and the set temperature 1 (the ECU determines the opening degree according to the temperature difference and the three-way mixing valve 17 opening degree MAP), and the exhaust temperature is not higher than the set temperature 4. The temperature of the intake air of the diesel engine 9 is increased, the combustion temperature is increased, the exhaust temperature is increased, the aftertreatment system is in an optimal exhaust temperature state, the activation of the HCI fuel injection system for increasing the exhaust temperature is reduced or avoided, the risk of DOC blockage is reduced, the passive regeneration efficiency of the DPF is kept high, and the risk of urea crystallization caused by urea injection is reduced. The exhaust temperature of the diesel engine is in an appropriate temperature range, the frequent activation of the thermal management program is avoided, and the fuel consumption is reduced.

[0050] When the diesel engine is powered off and stopped, the three-way mixing valve 17 is driven to return to the initial state of the bypass intake pipe 3 being fully closed and the intercooling pipe 19 being fully opened under the mechanical reset. Embodiment Three

[0052] As Figure 1As shown, the specific embodiment provides a diesel engine system, which comprises a turbocharger 1, an intercooler 6, a diesel engine 9 and an aftertreatment assembly 12, the aftertreatment assembly 12 being communicated with an exhaust pipe 10, and further comprises the device for preventing diesel engine urea crystallization of the second specific embodiment.

[0053] Preferably, the bypass intake pipe 3 is integrated with the intercooler 6, and specifically, the bypass intake pipe 3 is mounted inside the intercooler 6 housing through a bracket, the bracket adopts a U-shaped structure and is provided with support feet at both ends, the support feet are bolted with the intercooler 6 housing, so that the installation space of the bypass intake pipe 3 in the vehicle can be reduced, and the assembly is facilitated; or the bypass intake pipe 3 can be arranged in the intercooler 6 housing. The fourth specific embodiment

[0055] The specific embodiment provides a vehicle, which comprises the diesel engine system of the third specific embodiment.

[0056] 1. By arranging the bypass intake pipe 3, the fresh air can be controlled to directly enter the diesel engine 9 without passing through the intercooler 6, the exhaust temperature of the diesel engine 9 is improved, the exhaust gas temperature entering the aftertreatment assembly is increased, and the urea crystallization is better inhibited;

[0057] 2. By arranging the one-way valve 4, the gas backflow can be prevented; by arranging the throttle valve, the proportion of the fresh air directly entering the diesel engine 9 and the fresh air entering the diesel engine 9 through the intercooler 6 can be controlled in cooperation with the bypass valve 2, so that the dual requirements of fuel economy and prevention of urea crystallization are met;

[0058] 3. By arranging the electric switch to control the opening and closing of the fan assembly 7, the diesel engine 9 fan can be closed when starting at low temperature, so that the temperature of the diesel engine 9 when starting at low temperature is improved.

[0059] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for preventing urea crystallization in a diesel engine, comprising an exhaust gas temperature sensor, said exhaust gas temperature sensor being disposed at the intake end (10) of an aftertreatment assembly, characterized in that, Also comprising: a bypass intake pipe (3) whose intake end communicates with the intake end of the intercooler (6), and whose outlet end communicates with the diesel engine intake pipe (8); the bypass intake pipe (3) is communicated with the intake end of the intercooler through a three-way mixing valve (17); the exhaust temperature sensor and the bypass valve (2) are electrically connected with the controller.

2. The apparatus for preventing crystallization of diesel engine urea according to claim 1, wherein In the gas flow direction, the bypass intake pipe (3) is provided with a bypass valve (2), and the bypass intake pipe (3) is provided with a one-way valve (4) at the front end of the bypass valve (2), which is directed to the diesel engine intake pipe (8).

3. The apparatus for preventing crystallization of diesel engine urea according to claim 2, wherein Also comprising a throttle valve (5) arranged at the outlet end of the intercooler (6) and the diesel engine intake pipe (8), which is electrically connected with the controller.

4. The apparatus for preventing crystallization of diesel engine urea according to claim 3, wherein Also comprising a flow sensor arranged at the outlet end of the intercooler (6) and in front of the throttle valve (5) in the gas flow direction.

5. The apparatus for preventing crystallization of diesel engine urea according to claim 1, wherein The bypass intake pipe (3) is communicated with the intake end of the intercooler (6) through a three-way mixing valve (17), and the diesel engine intake pipe (8) is communicated with a venturi ejector device (13) at the rear end in the gas flow direction, and the intake end of the venturi ejector device (13) is communicated with the outlet end of the bypass intake pipe (3) and the outlet end of the intercooler (6).

6. The apparatus for preventing crystallization of diesel engine urea according to any one of claims 1 to 5, wherein Also comprising an electric switch electrically connected with the fan assembly (7) of the diesel engine, which is electrically connected with the controller.

7. A diesel engine system comprising a turbocharger (1), an intercooler (6), a diesel engine (9) and an aftertreatment assembly (12), characterized by Also comprising the device for preventing diesel engine urea crystallization according to claim 6.

8. The diesel engine system of claim 7, wherein The bypass intake pipe (3) is integrated with the intercooler (6).

9. The diesel engine system of claim 8, wherein The bypass intake pipe (3) is arranged inside the intercooler (6) shell through a bracket.

10. A vehicle characterized by comprising: Comprising the diesel engine system according to claim 9.

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