Diesel engine aftertreatment system

Abstract

This utility model discloses an aftertreatment system for a diesel engine, addressing the problem in related technologies where aftertreatment systems cannot guarantee emission compliance while controlling costs. A three-way pipe connects the engine exhaust manifold to a first exhaust pipe and a second exhaust pipe. An electronically controlled valve controls the flow of exhaust gas through the pipes. In the second exhaust pipe, a turbocharger unit reduces the exhaust gas temperature and increases the fresh air intake, thereby controlling the temperature of the exhaust gas in the aftertreatment unit. This ensures the aftertreatment unit operates within its optimal temperature range, guaranteeing NO emission compliance. X The conversion efficiency is at a high level, and there is no need to develop new catalyst materials, which reduces costs.

Description

Technical Field

[0001] This utility model relates to the field of automotive technology, and in particular to an after-treatment system for diesel engines. Background Technology

[0002] Currently, the N of selective catalytic reduction (SCR) Conversion efficiency is closely related to operating temperature, exhibiting a typical inverted U-shaped relationship. Under low-temperature conditions, due to incomplete urea decomposition and insufficient catalyst activity, the NO content of SCR is low. X The conversion efficiency is relatively low; as the temperature rises to the optimal operating range, the NO of SCR decreases. X The conversion efficiency reaches its peak; however, when the temperature exceeds a certain level, due to problems such as excessive oxidation of NH3 and catalyst sintering, the NO content of SCR decreases. X The conversion efficiency will then decrease significantly.

[0003] The commercial vehicle market continues to see a surge in demand for high-horsepower, high-torque engines. These engine systems often operate over a wider range of high temperatures, placing greater demands on the temperature adaptability of SCR (Selective Catalytic Reduction). To address this challenge, related technologies commonly employ methods such as optimizing catalyst formulations (e.g., increasing the content of precious metals) and developing novel catalyst materials. However, these methods have also led to a significant increase in the cost of aftertreatment systems, including SCR.

[0004] Therefore, how to control costs while ensuring emissions meet standards has become an important issue for after-treatment systems. Utility Model Content

[0005] The purpose of this invention is to provide an aftertreatment system for diesel engines, which solves the problem in related technologies that aftertreatment systems cannot guarantee emission compliance while controlling costs.

[0006] This utility model provides a control system for a diesel engine, the system including a diesel engine, a three-way pipe, a first exhaust pipe, a second exhaust pipe, an electronically controlled valve, and an aftertreatment unit; The first end of the three-way pipe is connected to the exhaust manifold of the diesel engine; One end of the first exhaust pipe is connected to the second end of the three-way pipe; One end of the second exhaust pipe is connected to the third end of the three-way pipe; The first air inlet of the after-treatment unit is connected to the other end of the first exhaust pipe away from the three-way pipe, and the second air inlet of the after-treatment unit is connected to the other end of the second exhaust pipe away from the three-way pipe. The diesel engine is equipped with an engine controller, which is connected to the electronically controlled valve located in the second exhaust pipe via a bus.

[0007] In one possible implementation, the system further includes a turbocharger unit; The turbocharger unit is located in the second exhaust pipe, and the engine controller and the turbocharger unit are connected via a bus.

[0008] In one possible implementation, the aftertreatment system further includes an exhaust gas temperature detector located at the exhaust port; The engine controller is connected to the exhaust gas temperature detector; When the exhaust gas temperature detected by the exhaust gas temperature detector is greater than or equal to a first preset temperature and less than or equal to a second preset temperature, the engine controller controls the electronically controlled valve to be in a closed state.

[0009] In one possible implementation, the aftertreatment system further includes an after-exhaust temperature detector located at the end of the exhaust manifold of the diesel engine. The engine controller is connected to the exhaust temperature detector after the turbine; When the exhaust gas temperature detected by the exhaust gas temperature detector is greater than the second preset temperature, the engine controller controls the electronically controlled valve to be in the open state.

[0010] In one possible implementation, the turbocharger unit includes a turbo end and a pressure end, the turbo end being disposed within the second exhaust pipe, and the pressure end being connected to the intake manifold of the diesel engine.

[0011] In one possible implementation, when the electronically controlled valve is in the open state, the engine controller controls the vortex end to be in the exhaust gas cooling state, and the engine controller controls the pressure end to be in the air compression state.

[0012] In one possible implementation, when the electronically controlled valve is in the closed state, the first exhaust pipe is connected to the exhaust manifold of the diesel engine. When the electronically controlled valve is in the open state, the first exhaust pipe and the second exhaust pipe are connected to the exhaust manifold of the diesel engine.

[0013] In one possible implementation, the diesel engine is equipped with a turbocharger, and the engine controller is equipped with a signal transmitter and a signal receiver.

[0014] In one possible implementation, the bus is a CAN bus.

[0015] In one possible implementation, the aftertreatment unit includes an oxidation catalyst (DOC), a diesel particulate filter (DPF), and a selective catalytic reduction (SCR) connected in sequence.

[0016] In this invention, when the engine operates under high load and high power conditions, causing an abnormal rise in exhaust temperature after the turbine, the invention can control the flow of exhaust gas through an electronically controlled valve. In the second exhaust gas pipe, a post-turbocharger unit reduces the exhaust temperature and increases the fresh air intake, thereby controlling the temperature of the exhaust gas in the aftertreatment unit. This ensures the aftertreatment unit operates within its optimal temperature range, guaranteeing NO reduction. X The conversion efficiency is at a high level, and there is no need to develop new catalyst materials, which reduces costs.

[0017] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of this invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the structure of the aftertreatment system for a diesel engine provided in an embodiment of this utility model; Figure 2 A schematic diagram of the hardware structure of a diesel engine controller provided in an embodiment of this utility model. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0021] Furthermore, in the description of the embodiments of this utility model, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this utility model, "multiple" means two or more.

[0022] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0023] Currently, the N of selective catalytic reduction (SCR) Conversion efficiency is closely related to operating temperature, exhibiting a typical inverted U-shaped relationship. Under low-temperature conditions, due to incomplete urea decomposition and insufficient catalyst activity, the NO content of SCR is low. X The conversion efficiency is relatively low; as the temperature rises to the optimal operating range, the NO of SCR decreases. X The conversion efficiency reaches its peak; however, when the temperature exceeds a certain level, due to problems such as excessive oxidation of NH3 and catalyst sintering, the NO content of SCR decreases. X The conversion efficiency will then decrease significantly.

[0024] The commercial vehicle market continues to see a surge in demand for high-horsepower, high-torque engines. These engine systems often operate over a wider range of high temperatures, placing greater demands on the temperature adaptability of SCR (Selective Catalytic Reduction). To address this challenge, related technologies commonly employ methods such as optimizing catalyst formulations (e.g., increasing the content of precious metals) and developing novel catalyst materials. However, these methods have also led to a significant increase in the cost of aftertreatment systems, including SCR.

[0025] Therefore, how to control costs while ensuring emissions meet standards has become an important issue for after-treatment systems.

[0026] In view of this, the present invention provides an aftertreatment system for a diesel engine to solve the problem that aftertreatment systems in related technologies cannot guarantee emission compliance while controlling costs.

[0027] The concept of this utility model can be summarized as follows: The engine exhaust manifold is connected to the first and second exhaust pipes via a three-way pipe. An electronically controlled valve controls the flow of exhaust gas from the engine. In the second exhaust pipe, a turbocharger unit reduces the exhaust gas temperature and increases the fresh air intake, thereby controlling the temperature of the exhaust gas in the aftertreatment unit. This ensures the aftertreatment unit operates within its optimal temperature range, guaranteeing NO emission reduction. X The conversion efficiency is at a high level, and there is no need to develop new catalyst materials, which reduces costs.

[0028] After introducing the main ideas of the embodiments of this utility model, the following is a brief introduction to the application scenarios to which the technical solutions of the embodiments of this utility model are applicable. It should be noted that the application scenarios described below are only for illustrating the embodiments of this utility model and are not intended to limit it. In specific implementation, the technical solutions provided by the embodiments of this utility model can be flexibly applied according to actual needs.

[0029] To facilitate understanding of the diesel engine aftertreatment system provided in this embodiment of the present invention, further explanation will be provided below with reference to the accompanying drawings.

[0030] Figure 1 A schematic diagram of the structure of the aftertreatment system for a diesel engine provided in an embodiment of this utility model is shown below. Figure 1 As shown, the system includes a diesel engine, a three-way pipe, a first exhaust pipe, a second exhaust pipe, electronically controlled valves, a turbocharger unit, and an aftertreatment unit. The first end of the three-way pipe is connected to the exhaust manifold of the diesel engine; One end of the first exhaust pipe is connected to the second end of the three-way pipe; One end of the second exhaust pipe is connected to the third end of the three-way pipe; The first air inlet of the aftertreatment unit is connected to the other end of the first exhaust pipe away from the three-way pipe, and the second air inlet of the aftertreatment unit is connected to the other end of the second exhaust pipe away from the three-way pipe. The diesel engine is equipped with an engine controller, which is connected to the electronically controlled valve located in the second exhaust pipe via a bus. The turbocharger unit is located in the second exhaust pipe, and the engine controller and the turbocharger unit are connected via a bus.

[0031] In one possible implementation, the aftertreatment system also includes an exhaust gas temperature detector located at the exhaust port. The engine controller is connected to the exhaust gas temperature detector; When the exhaust gas temperature detected by the exhaust gas temperature detector is greater than or equal to the first preset temperature and less than or equal to the second preset temperature, the engine controller controls the electronically controlled valve to be in the closed state.

[0032] In one possible implementation, the aftertreatment system also includes an after-exhaust temperature detector located at the end of the diesel engine's exhaust manifold. The engine controller is connected to the exhaust temperature detector after the turbine. When the exhaust gas temperature detected by the exhaust gas temperature detector is greater than the second preset temperature, the engine controller controls the electronically controlled valve to be in the open state.

[0033] In one possible implementation, the turbocharger unit includes a turbo end and a pressure end, with the turbo end disposed in the second exhaust pipe and the pressure end connected to the intake manifold of the diesel engine.

[0034] In one possible implementation, when the electronically controlled valve is in the open state, the engine controller controls the turbine end to be in the exhaust gas cooling state, and the engine controller controls the pressure end to be in the air compression state.

[0035] In one possible implementation, when the electronically controlled valve is in the closed state, the first exhaust pipe is connected to the exhaust manifold of the diesel engine. When the electronically controlled valve is in the open position, both the first and second exhaust pipes are connected to the exhaust manifold of the diesel engine.

[0036] In one possible implementation, the diesel engine is equipped with a turbocharger, and the engine controller is equipped with a signal transmitter and a signal receiver.

[0037] In one possible implementation, the bus is a CAN bus.

[0038] In one possible implementation, the aftertreatment unit includes an oxidation catalyst (DOC), a diesel particulate filter (DPF), and a selective catalytic reduction (SCR) connected in sequence.

[0039] For example, the first preset temperature is T2, and the second preset temperature is T3. T2-T3 is the optimal operating range for SCR, with high and stable conversion efficiency.

[0040] When the exhaust gas temperature T_SCR detected by the exhaust gas temperature detector is between T2 and T3, the electronically controlled valve P is closed, and the exhaust gas enters exhaust gas line 1, then enters the aftertreatment unit. At this time, the SCR is in a highly efficient and stable state, ensuring NO X Emissions meet regulatory requirements.

[0041] When the exhaust gas temperature T1 detected by the after-scroll exhaust temperature detector is higher than T3, the engine controller controls the electronically controlled valve P to open, allowing exhaust gas to enter exhaust pipe 2. After passing through the scroll end of the after-scroll turbocharger, the exhaust gas temperature drops to T2. Fresh air is then compressed by the pressure-end impeller and enters the intake manifold together with the fresh air compressed by the turbocharger of the diesel engine to participate in combustion. Due to the increase in intake air volume and air-fuel ratio, the after-scroll exhaust temperature T1 also decreases. This cycle continues until T_SCR is between T2 and T3, keeping SCR in a highly efficient and stable state, ensuring NO X Emissions meet regulatory requirements.

[0042] Figure 2 A schematic diagram of the hardware structure of the diesel engine controller provided in the embodiment of this utility model is shown below. Figure 2 As shown, the diesel engine controller includes a signal transmitter and a signal receiver. The signal transmitter can send control signals to the electronically controlled valves and the turbocharger unit, and the signal receiver can receive temperature signals sent by the exhaust gas temperature detector and the exhaust gas temperature detector.

[0043] In summary, in this invention, when the engine is under high load and high power conditions, causing an abnormal increase in the exhaust temperature after the turbine, this invention can control the flow of exhaust gas through an electronically controlled valve. In the second exhaust gas pipe, the exhaust temperature is reduced by the post-turbocharger unit, and the fresh air intake is increased. This controls the temperature of the exhaust gas in the aftertreatment unit, ensuring that the aftertreatment unit operates within its optimal temperature range and guaranteeing N... The conversion efficiency is at a high level, and there is no need to develop new catalyst materials, which reduces costs.

[0044] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. An aftertreatment system for a diesel engine, characterized in that, The system includes a diesel engine, a three-way pipe, a first exhaust pipe, a second exhaust pipe, an electronically controlled valve, and an after-treatment unit; The first end of the three-way pipe is connected to the exhaust manifold of the diesel engine; One end of the first exhaust pipe is connected to the second end of the three-way pipe; One end of the second exhaust pipe is connected to the third end of the three-way pipe; The first air inlet of the after-treatment unit is connected to the other end of the first exhaust pipe away from the three-way pipe, and the second air inlet of the after-treatment unit is connected to the other end of the second exhaust pipe away from the three-way pipe. The diesel engine is equipped with an engine controller, which is connected to the electronically controlled valve located in the second exhaust pipe via a bus.

2. The system according to claim 1, characterized in that, The system also includes a turbocharger unit; The turbocharger unit is located in the second exhaust pipe, and the engine controller and the turbocharger unit are connected via a bus.

3. The system according to claim 1, characterized in that, The aftertreatment system also includes an exhaust gas temperature detector located at the exhaust port; The engine controller is connected to the exhaust gas temperature detector; When the exhaust gas temperature detected by the exhaust gas temperature detector is greater than or equal to a first preset temperature and less than or equal to a second preset temperature, the engine controller controls the electronically controlled valve to be in a closed state.

4. The system according to claim 1, characterized in that, The aftertreatment system also includes an after-draft exhaust temperature detector located at the end of the exhaust manifold of the diesel engine. The engine controller is connected to the exhaust temperature detector after the turbine; When the exhaust gas temperature detected by the exhaust gas temperature detector is greater than the second preset temperature, the engine controller controls the electronically controlled valve to be in the open state.

5. The system according to claim 2, characterized in that, The turbocharger unit includes a turbo end and a pressure end. The turbo end is disposed in the second exhaust pipe, and the pressure end is connected to the intake manifold of the diesel engine.

6. The system according to claim 5, characterized in that, When the electronically controlled valve is in the open state, the engine controller controls the vortex end to be in the exhaust gas cooling state, and the engine controller controls the pressure end to be in the air compression state.

7. The system according to claim 1, characterized in that, When the electronically controlled valve is in the closed state, the first exhaust pipe is connected to the exhaust manifold of the diesel engine; When the electronically controlled valve is in the open state, the first exhaust pipe and the second exhaust pipe are connected to the exhaust manifold of the diesel engine.

8. The system according to claim 1, characterized in that, The diesel engine is equipped with a turbocharger, and the engine controller is equipped with a signal transmitter and a signal receiver.

9. The system according to claim 1, characterized in that, The bus in question is a CAN bus.

10. The system according to claim 1, characterized in that, The aftertreatment unit includes an oxidation catalyst (DOC), a diesel particulate filter (DPF), and a selective catalytic reduction (SCR) connected in sequence.

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